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Liu H, Simonian NT, Pouch AM, Iaizzo PA, Gorman JH, Gorman RC, Sacks MS. A Computational Pipeline for Patient-Specific Prediction of the Postoperative Mitral Valve Functional State. J Biomech Eng 2023; 145:111002. [PMID: 37382900 PMCID: PMC10405284 DOI: 10.1115/1.4062849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 06/08/2023] [Accepted: 06/13/2023] [Indexed: 06/30/2023]
Abstract
While mitral valve (MV) repair remains the preferred clinical option for mitral regurgitation (MR) treatment, long-term outcomes remain suboptimal and difficult to predict. Furthermore, pre-operative optimization is complicated by the heterogeneity of MR presentations and the multiplicity of potential repair configurations. In the present work, we established a patient-specific MV computational pipeline based strictly on standard-of-care pre-operative imaging data to quantitatively predict the post-repair MV functional state. First, we established human mitral valve chordae tendinae (MVCT) geometric characteristics obtained from five CT-imaged excised human hearts. From these data, we developed a finite-element model of the full patient-specific MV apparatus that included MVCT papillary muscle origins obtained from both the in vitro study and the pre-operative three-dimensional echocardiography images. To functionally tune the patient-specific MV mechanical behavior, we simulated pre-operative MV closure and iteratively updated the leaflet and MVCT prestrains to minimize the mismatch between the simulated and target end-systolic geometries. Using the resultant fully calibrated MV model, we simulated undersized ring annuloplasty (URA) by defining the annular geometry directly from the ring geometry. In three human cases, the postoperative geometries were predicted to 1 mm of the target, and the MV leaflet strain fields demonstrated close agreement with noninvasive strain estimation technique targets. Interestingly, our model predicted increased posterior leaflet tethering after URA in two recurrent patients, which is the likely driver of long-term MV repair failure. In summary, the present pipeline was able to predict postoperative outcomes from pre-operative clinical data alone. This approach can thus lay the foundation for optimal tailored surgical planning for more durable repair, as well as development of mitral valve digital twins.
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Affiliation(s)
- Hao Liu
- James T. Willerson Center for Cardiovascular Modeling and Simulation, The Oden Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712-1229
| | - Natalie T. Simonian
- James T. Willerson Center for Cardiovascular Modeling and Simulation, The Oden Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712-1229
| | - Alison M. Pouch
- Departments of Radiology and Bioengineering, University of Pennsylvania, Philadelphia, PA 19104
| | - Paul A. Iaizzo
- Visible Heart Laboratories, Department of Surgery, University of Minnesota, Minneapolis, MN 55455
| | - Joseph H. Gorman
- Gorman Cardiovascular Research Group, Department of Surgery, Smilow Center for Translational Research, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Robert C. Gorman
- Gorman Cardiovascular Research Group, Department of Surgery, Smilow Center for Translational Research, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Michael S. Sacks
- James T. Willerson Center for Cardiovascular Modeling and Simulation, The Oden Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712-1229
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Simonian NT, Liu H, Vakamudi S, Pirwitz MJ, Pouch AM, Gorman JH, Gorman RC, Sacks MS. Patient-Specific Quantitative In-Vivo Assessment of Human Mitral Valve Leaflet Strain Before and After MitraClip Repair. Cardiovasc Eng Technol 2023; 14:677-693. [PMID: 37670097 DOI: 10.1007/s13239-023-00680-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Accepted: 08/23/2023] [Indexed: 09/07/2023]
Abstract
PURPOSE Mitral regurgitation (MR) is a highly prevalent and deadly cardiac disease characterized by improper mitral valve (MV) leaflet coaptation. Among the plethora of available treatment strategies, the MitraClip is an especially safe option, but optimizing its long-term efficacy remains an urgent challenge. METHODS We applied our noninvasive image-based strain computation pipeline [1] to intraoperative transesophageal echocardiography datasets taken from ten patients undergoing MitraClip repair, spanning a range of MR etiologies and MitraClip configurations. We then analyzed MV leaflet strains before and after MitraClip implementation to develop a better understanding of (1) the pre-operative state of human regurgitant MV, and (2) the MitraClip's impact on the MV leaflet deformations. RESULTS The MV pre-operative strain fields were highly variable, underscoring both the heterogeneity of the MR in the patient population and the need for patient-specific treatment approaches. Similarly, there were no consistent overall post-operative strain patterns, although the average A2 segment radial strain difference between pre- and post-operative states was consistently positive. In contrast, the post-operative strain fields were better correlated to their respective pre-operative strain fields than to the inter-patient post-operative strain fields. This quantitative result implies that the patient specific pre-operative state of the MV guides its post-operative deformation, which suggests that the post-operative state can be predicted using pre-operative data-derived modelling alone. CONCLUSIONS The pre-operative MV leaflet strain patterns varied considerably across the range of MR disease states and after MitraClip repair. Despite large inter-patient heterogeneity, the post-operative deformation appears principally dictated by the pre-operative deformation state. This novel finding suggests that though the variation in MR functional state and MitraClip-induced deformation were substantial, the post-operative state can be predicted from the pre-operative data alone. This study suggests that, with use of larger patient cohort and corresponding long-term outcomes, quantitative predictive factors of MitraClip durability can be identified.
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Affiliation(s)
- Natalie T Simonian
- James T. Willerson Center for Cardiovascular Modeling and Simulation, The Oden Institute for Computational Engineering and Sciences and the Department of Biomedical Engineering, The University of Texas at Austin , 201 East 24th St., Stop C0200, Austin, TX, 78712-1229, USA
| | - Hao Liu
- James T. Willerson Center for Cardiovascular Modeling and Simulation, The Oden Institute for Computational Engineering and Sciences and the Department of Biomedical Engineering, The University of Texas at Austin , 201 East 24th St., Stop C0200, Austin, TX, 78712-1229, USA
| | - Sneha Vakamudi
- Ascension Texas Cardiovascular & Division of Cardiology, Department of Internal Medicine, Dell Medical School, University of Texas, Austin, TX, USA
| | - Mark J Pirwitz
- Ascension Texas Cardiovascular & Division of Cardiology, Department of Internal Medicine, Dell Medical School, University of Texas, Austin, TX, USA
| | - Alison M Pouch
- Gorman Cardiovascular Research Group, Smilow Center for Translational Research, Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Joseph H Gorman
- Gorman Cardiovascular Research Group, Smilow Center for Translational Research, Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Robert C Gorman
- Gorman Cardiovascular Research Group, Smilow Center for Translational Research, Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Michael S Sacks
- James T. Willerson Center for Cardiovascular Modeling and Simulation, The Oden Institute for Computational Engineering and Sciences and the Department of Biomedical Engineering, The University of Texas at Austin , 201 East 24th St., Stop C0200, Austin, TX, 78712-1229, USA.
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Xue Y, Kossar AP, Abramov A, Frasca A, Sun M, Zyablitskaya M, Paik D, Kalfa D, Della Barbera M, Thiene G, Kozaki S, Kawashima T, Gorman JH, Gorman RC, Gillespie MJ, Carreon CK, Sanders SP, Levy RJ, Ferrari G. Age-related enhanced degeneration of bioprosthetic valves due to leaflet calcification, tissue crosslinking, and structural changes. Cardiovasc Res 2023; 119:302-315. [PMID: 35020813 PMCID: PMC10022861 DOI: 10.1093/cvr/cvac002] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 11/03/2021] [Accepted: 01/06/2022] [Indexed: 11/14/2022] Open
Abstract
AIMS Bioprosthetic heart valves (BHVs), made from glutaraldehyde-fixed heterograft materials, are subject to more rapid structural valve degeneration (SVD) in paediatric and young adult patients. Differences in blood biochemistries and propensity for disease accelerate SVD in these patients, which results in multiple re-operations with compounding risks. The goal of this study is to investigate the mechanisms of BHV biomaterial degeneration and present models for studying SVD in young patients and juvenile animal models. METHODS AND RESULTS We studied SVD in clinical BHV explants from paediatric and young adult patients, juvenile sheep implantation model, rat subcutaneous implants, and an ex vivo serum incubation model. BHV biomaterials were analysed for calcification, collagen microstructure (alignment and crimp), and crosslinking density. Serum markers of calcification and tissue crosslinking were compared between young and adult subjects. We demonstrated that immature subjects were more susceptible to calcification, microstructural changes, and advanced glycation end products formation. In vivo and ex vivo studies comparing immature and mature subjects mirrored SVD in clinical observations. The interaction between host serum and BHV biomaterials leads to significant structural and biochemical changes which impact their functions. CONCLUSIONS There is an increased risk for accelerated SVD in younger subjects, both experimental animals and patients. Increased calcification, altered collagen microstructure with loss of alignment and increased crimp periods, and increased crosslinking are three main characteristics in BHV explants from young subjects leading to SVD. Together, our studies establish a basis for assessing the increased susceptibility of BHV biomaterials to accelerated SVD in young patients.
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Affiliation(s)
- Yingfei Xue
- Department of Surgery, Columbia University, New York, NY, USA
| | | | - Alexey Abramov
- Department of Surgery, Columbia University, New York, NY, USA
| | - Antonio Frasca
- Department of Surgery, Columbia University, New York, NY, USA
| | - Mingze Sun
- Department of Surgery, Columbia University, New York, NY, USA
| | | | - David Paik
- Department of Ophthalmology, Columbia University, New York, NY, USA
| | - David Kalfa
- Division of Cardiac, Thoracic and Vascular Surgery, Section of Pediatric and Congenital Cardiac Surgery, Department of Surgery, New-York Presbyterian—Morgan Stanley Children’s Hospital, Columbia University Medical Center, New York, NY, USA
| | - Mila Della Barbera
- Department of Cardiac, Thoracic, Vascular Science and Public Health, University of Padua, Medical School, Padua, Italy
| | - Gaetano Thiene
- Department of Cardiac, Thoracic, Vascular Science and Public Health, University of Padua, Medical School, Padua, Italy
| | - Satoshi Kozaki
- Gorman Cardiovascular Research Group, Department of Surgery, Smilow Center for Translational Research, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Takayuki Kawashima
- Gorman Cardiovascular Research Group, Department of Surgery, Smilow Center for Translational Research, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Joseph H Gorman
- Gorman Cardiovascular Research Group, Department of Surgery, Smilow Center for Translational Research, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Robert C Gorman
- Gorman Cardiovascular Research Group, Department of Surgery, Smilow Center for Translational Research, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Matthew J Gillespie
- Gorman Cardiovascular Research Group, Department of Surgery, Smilow Center for Translational Research, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Chrystalle Katte Carreon
- The Cardiac Registry, Department of Cardiology, Boston Children’s Hospital, Boston, MA, USA
- The Cardiac Registry, Department of Pathology, Boston Children’s Hospital, Boston, MA, USA
- The Cardiac Registry, Department of Cardiac Surgery, Boston Children’s Hospital, Boston, MA, USA
- Department of Pathology, Boston Children’s Hospital and Harvard Medical School, Boston, MA, USA
| | - Stephen P Sanders
- The Cardiac Registry, Department of Cardiology, Boston Children’s Hospital, Boston, MA, USA
- The Cardiac Registry, Department of Pathology, Boston Children’s Hospital, Boston, MA, USA
- The Cardiac Registry, Department of Cardiac Surgery, Boston Children’s Hospital, Boston, MA, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA, USA
| | - Robert J Levy
- The Pediatric Heart Valve Center & Division of Cardiology, Department of Pediatrics, The Children’s Hospital of Philadelphia, Philadelphia, PA, USA
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Rego BV, Khalighi AH, Gorman JH, Gorman RC, Sacks MS. Simulation of Mitral Valve Plasticity in Response to Myocardial Infarction. Ann Biomed Eng 2023; 51:71-87. [PMID: 36030332 DOI: 10.1007/s10439-022-03043-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 08/01/2022] [Indexed: 01/13/2023]
Abstract
Left ventricular myocardial infarction (MI) has broad and debilitating effects on cardiac function. In many cases, MI leads to ischemic mitral regurgitation (IMR), a condition characterized by incompetency of the mitral valve (MV). IMR has many deleterious effects as well as a high mortality rate. While various clinical treatments for IMR exist, success of these procedures remains limited, in large part because IMR dramatically alters the geometry and function of the MV in ways that are currently not well understood. Previous investigations of post-MI MV remodeling have elucidated that MV tissues have a significant ability to undergo a form of permanent inelastic deformations in the first phase of the post-MI period. These changes appear to be attributable to the altered loading and boundary conditions on the MV itself, as opposed to an independent pathophysiological process. Mechanistically, these results suggest that the MV mostly responds passively to MI during the first 8 weeks post-MI by undergoing a permanent deformation. In the present study, we developed the first computational model of this post-MI MV remodeling process, which we term "mitral valve plasticity." Integrating methodologies and insights from previous studies of in vivo ovine MV function, image-based patient-specific model development, and post-MI MV adaptation, we constructed a representative geometric model of a pre-MI MV. We then performed finite element simulations of the entire MV apparatus under time-dependent boundary conditions and accounting for changes to material properties equivalent to those observed 0-8 weeks post-MI. Our results suggest that during this initial period of adaptation, the MV response to MI can be accurately modeled using a soft tissue plasticity approach, similar to permanent set frameworks that have been applied previously in the context of exogenously crosslinked tissues.
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Affiliation(s)
- Bruno V Rego
- James T. Willerson Center for Cardiovascular Modeling and Simulation, Oden Institute for Computational Engineering and Sciences and the Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, USA
| | - Amir H Khalighi
- James T. Willerson Center for Cardiovascular Modeling and Simulation, Oden Institute for Computational Engineering and Sciences and the Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, USA
| | - Joseph H Gorman
- Gorman Cardiovascular Research Group, Smilow Center for Translational Research, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Robert C Gorman
- Gorman Cardiovascular Research Group, Smilow Center for Translational Research, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Michael S Sacks
- James T. Willerson Center for Cardiovascular Modeling and Simulation, Oden Institute for Computational Engineering and Sciences and the Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, USA.
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Rego BV, Khalighi AH, Lai EK, Gorman RC, Gorman JH, Sacks MS. In vivo assessment of mitral valve leaflet remodelling following myocardial infarction. Sci Rep 2022; 12:18012. [PMID: 36289435 PMCID: PMC9606267 DOI: 10.1038/s41598-022-22790-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 10/19/2022] [Indexed: 01/24/2023] Open
Abstract
Each year, more than 40,000 people undergo mitral valve (MV) repair surgery domestically to treat regurgitation caused by myocardial infarction (MI). Although continual MV tissue remodelling following repair is believed to be a major contributor to regurgitation recurrence, the effects of the post-MI state on MV remodelling remain poorly understood. This lack of understanding limits our ability to predict the remodelling of the MV both post-MI and post-surgery to facilitate surgical planning. As a necessary first step, the present study was undertaken to noninvasively quantify the effects of MI on MV remodelling in terms of leaflet geometry and deformation. MI was induced in eight adult Dorset sheep, and real-time three-dimensional echocardiographic (rt-3DE) scans were collected pre-MI as well as at 0, 4, and 8 weeks post-MI. A previously validated image-based morphing pipeline was used to register corresponding open- and closed-state scans and extract local in-plane strains throughout the leaflet surface at systole. We determined that MI induced permanent changes in leaflet dimensions in the diastolic configuration, which increased with time to 4 weeks, then stabilised. MI substantially affected the systolic shape of the MV, and the range of stretch experienced by the MV leaflet at peak systole was substantially reduced when referred to the current time-point. Interestingly, when we referred the leaflet strains to the pre-MI configuration, the systolic strains remained very similar throughout the post-MI period. Overall, we observed that post-MI ventricular remodeling induced permanent changes in the MV leaflet shape. This predominantly affected the MV's diastolic configuration, leading in turn to a significant decrease in the range of stretch experienced by the leaflet when referenced to the current diastolic configuration. These findings are consistent with our previous work that demonstrated increased plastic (i.e. non-recoverable) leaflet deformations post-MI, that was completely accounted for by the associated changes in collagen fiber structure. Moreover, we demonstrated through noninvasive methods that the state of the MV leaflet can elucidate the progression and extent of MV adaptation following MI and is thus highly relevant to the design of current and novel patient specific minimally invasive surgical repair strategies.
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Affiliation(s)
- Bruno V. Rego
- grid.89336.370000 0004 1936 9924James T. Willerson Center for Cardiovascular Modeling and Simulation, Oden Institute for Computational Engineering and Sciences, and the Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX USA
| | - Amir H. Khalighi
- grid.89336.370000 0004 1936 9924James T. Willerson Center for Cardiovascular Modeling and Simulation, Oden Institute for Computational Engineering and Sciences, and the Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX USA
| | - Eric K. Lai
- grid.25879.310000 0004 1936 8972Gorman Cardiovascular Research Group, Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA USA
| | - Robert C. Gorman
- grid.25879.310000 0004 1936 8972Gorman Cardiovascular Research Group, Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA USA
| | - Joseph H. Gorman
- grid.25879.310000 0004 1936 8972Gorman Cardiovascular Research Group, Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA USA
| | - Michael S. Sacks
- grid.89336.370000 0004 1936 9924James T. Willerson Center for Cardiovascular Modeling and Simulation, Oden Institute for Computational Engineering and Sciences, and the Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX USA
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Simonian NT, Liu H, Pouch AM, Gorman JH, Gorman RC, Sacks MS. Quantitative in vivo assessment of human mitral valve coaptation area after undersized ring annuloplasty repair for ischemic mitral regurgitation. JTCVS Tech 2022; 16:49-59. [PMID: 36510522 PMCID: PMC9735426 DOI: 10.1016/j.xjtc.2022.09.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 08/29/2022] [Accepted: 09/13/2022] [Indexed: 11/08/2022] Open
Abstract
Objectives Long-term outcomes of mitral valve repair procedures to correct ischemic mitral regurgitation remain unpredictable, due to an incomplete understanding of the disease process and the inability to reliably quantify the coaptation zone using echocardiography. Our objective was to quantify patient-specific mitral valve coaptation behavior from clinical echocardiographic images obtained before and after repair to assess coaptation restoration and its relationship with long-term repair durability. Methods To circumvent the limitations of clinical imaging, we applied a simulation-based shape-matching technique that allowed high-fidelity reconstructions of the complete mitral valve in the systolic configuration. We then applied this method to an extant database of human regurgitant mitral valves before and after undersized ring annuloplasty to quantify the effect of the repair on mitral valve coaptation geometry. Results Our method was able to successfully resolve the coaptation zone into distinct contacting and redundant regions. Results indicated that in patients whose regurgitation recurred 6 months postrepair, both the contacting and redundant regions were larger immediately postrepair compared with patients with no recurrence (P < .05), even when normalized to account for generally larger recurrent valves. Conclusions Although increasing leaflet coaptation area is an intuitively obvious way to improve long-term repair durability, this study has implied that this may not be a reliable target for mitral valve repair. This study underscores the importance of a rigorous understanding of the consequences of repair techniques on mitral valve behavior, as well as a patient-specific approach to ischemic mitral regurgitation treatment within the context of mitral valve and left ventricle function.
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Key Words
- CMF, chordal mimicking force
- ED, end-diastolic
- ES, end-systolic
- FE, finite element
- IMR, ischemic mitral regurgitation
- LV, left ventricle
- MR, mitral regurgitation
- MV, mitral valve
- MVTa, mitral valve tenting area
- URA, undersized ring annuloplasty
- mitral valve imaging
- mitral valve mechanics
- mitral valve regurgitation
- mitral valve repair
- myocardial infarction
- rt-3DE, real-time 3-dimensional echocardiography
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Affiliation(s)
- Natalie T. Simonian
- James T. Willerson Center for Cardiovascular Modeling and Simulation, The Oden Institute for Computational Engineering and Sciences and the Department of Biomedical Engineering, The University of Texas at Austin, Austin, Tex
| | - Hao Liu
- James T. Willerson Center for Cardiovascular Modeling and Simulation, The Oden Institute for Computational Engineering and Sciences and the Department of Biomedical Engineering, The University of Texas at Austin, Austin, Tex
| | - Alison M. Pouch
- Departments of Radiology and Bioengineering, University of Pennsylvania, Philadelphia, Pa
| | - Joseph H. Gorman
- Department of Surgery, Smilow Center for Translational Research, Gorman Cardiovascular Research Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pa
| | - Robert C. Gorman
- Department of Surgery, Smilow Center for Translational Research, Gorman Cardiovascular Research Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pa
| | - Michael S. Sacks
- James T. Willerson Center for Cardiovascular Modeling and Simulation, The Oden Institute for Computational Engineering and Sciences and the Department of Biomedical Engineering, The University of Texas at Austin, Austin, Tex,Address for reprints: Michael S. Sacks, PhD, Department of Biomedical Engineering, The Oden Institute for Computational Engineering and Sciences, The University of Texas at Austin, 201 East 24th St, Stop C0200, Austin, TX 78712-1229.
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Jang C, Hui S, Zeng X, Cowan AJ, Wang L, Chen L, Morscher RJ, Reyes J, Frezza C, Hwang HY, Imai A, Saito Y, Okamoto K, Vaspoli C, Kasprenski L, Zsido GA, Gorman JH, Gorman RC, Rabinowitz JD. Metabolite Exchange between Mammalian Organs Quantified in Pigs. Cell Metab 2022; 34:1410. [PMID: 36070684 PMCID: PMC9514224 DOI: 10.1016/j.cmet.2022.08.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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Aly AH, Khandelwal P, Aly AH, Kawashima T, Mori K, Saito Y, Hung J, Gorman JH, Pouch AM, Gorman RC, Yushkevich PA. Fully Automated 3D Segmentation and Diffeomorphic Medial Modeling of the Left Ventricle Mitral Valve Complex in Ischemic Mitral Regurgitation. Med Image Anal 2022; 80:102513. [PMID: 35772323 DOI: 10.1016/j.media.2022.102513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 05/30/2022] [Accepted: 06/10/2022] [Indexed: 10/18/2022]
Abstract
There is an urgent unmet need to develop a fully-automated image-based left ventricle mitral valve analysis tool to support surgical decision making for ischemic mitral regurgitation patients. This requires an automated tool for segmentation and modeling of the left ventricle and mitral valve from immediate pre-operative 3D transesophageal echocardiography. Previous works have presented methods for semi-automatically segmenting and modeling the mitral valve, but do not include the left ventricle and do not avoid self-intersection of the mitral valve leaflets during shape modeling. In this study, we develop and validate a fully automated algorithm for segmentation and shape modeling of the left ventricular mitral valve complex from pre-operative 3D transesophageal echocardiography. We performed a 3-fold nested cross validation study on two datasets from separate institutions to evaluate automated segmentations generated by nnU-net with the expert manual segmentation which yielded average overall Dice scores of 0.82±0.03 (set A), 0.87±0.08 (set B) respectively. A deformable medial template was subsequently fitted to the segmentation to generate shape models. Comparison of shape models to the manual and automatically generated segmentations resulted in an average Dice score of 0.93-0.94 and 0.75-0.81 for the left ventricle and mitral valve, respectively. This is a substantial step towards automatically analyzing the left ventricle mitral valve complex in the operating room.
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Affiliation(s)
- Ahmed H Aly
- Division of Cardiothoracic Surgery, The Ohio State University, Columbus, OH, USA; Department of Bioengineering, School of Engineering and Applied Sciences, University of Pennsylvania, Philadelphia, PA, USA; Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, PA, USA.
| | - Pulkit Khandelwal
- Department of Bioengineering, School of Engineering and Applied Sciences, University of Pennsylvania, Philadelphia, PA, USA
| | - Abdullah H Aly
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA; The Ohio State College of Medicine, Columbus, OH, USA
| | - Takayuki Kawashima
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, PA, USA
| | - Kazuki Mori
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, PA, USA
| | - Yoshiaki Saito
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, PA, USA
| | - Judy Hung
- Department of Cardiology at Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Joseph H Gorman
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, PA, USA; Department of Surgery, University of Pennsylvania, Philadelphia, PA, USA
| | - Alison M Pouch
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Robert C Gorman
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, PA, USA; Department of Surgery, University of Pennsylvania, Philadelphia, PA, USA
| | - Paul A Yushkevich
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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Rego BV, Pouch AM, Gorman JH, Gorman RC, Sacks MS. Patient-Specific Quantification of Normal and Bicuspid Aortic Valve Leaflet Deformations from Clinically Derived Images. Ann Biomed Eng 2022; 50:1-15. [PMID: 34993699 PMCID: PMC9084616 DOI: 10.1007/s10439-021-02882-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 10/24/2021] [Indexed: 11/24/2022]
Abstract
The clinical benefit of patient-specific modeling of heart valve disease remains an unrealized goal, often a result of our limited understanding of the in vivo milieu. This is particularly true in assessing bicuspid aortic valve (BAV) disease, the most common cardiac congenital defect in humans, which leads to premature and severe aortic stenosis or insufficiency (AS/AI). However, assessment of BAV risk for AS/AI on a patient-specific basis is hampered by the substantial degree of anatomic and functional variations that remain largely unknown. The present study was undertaken to utilize a noninvasive computational pipeline ( https://doi.org/10.1002/cnm.3142 ) that directly yields local heart valve leaflet deformation information using patient-specific real-time three-dimensional echocardiographic imaging (rt-3DE) data. Imaging data was collected for patients with normal tricuspid aortic valve (TAV, [Formula: see text]) and those with BAV ([Formula: see text] with fused left and right coronary leaflets and [Formula: see text] with fused right and non-coronary leaflets), from which the medial surface of each leaflet was extracted. The resulting deformation analysis resulted in, for the first time, quantified differences between the in vivo functional deformations of the TAV and BAV leaflets. Our approach was able to capture the complex, heterogeneous surface deformation fields in both TAV and BAV leaflets. We were able to identify and quantify differences in stretch patterns between leaflet types, and found in particular that stretches experienced by BAV leaflets during closure differ from those of TAV leaflets in terms of both heterogeneity as well as overall magnitude. Deformation is a key parameter in the clinical assessment of valvular function, and serves as a direct means to determine regional variations in structure and function. This study is an essential step toward patient-specific assessment of BAV based on correlating leaflet deformation and AS/AI progression, as it provides a means for assessing patient-specific stretch patterns.
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Affiliation(s)
- Bruno V Rego
- James T. Willerson Center for Cardiovascular Modeling and Simulation, Oden Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Alison M Pouch
- Gorman Cardiovascular Research Group, Smilow Center for Translational Research, Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Joseph H Gorman
- Gorman Cardiovascular Research Group, Smilow Center for Translational Research, Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Robert C Gorman
- Gorman Cardiovascular Research Group, Smilow Center for Translational Research, Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Michael S Sacks
- James T. Willerson Center for Cardiovascular Modeling and Simulation, Oden Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, 78712, USA.
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10
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Moon BF, Iyer SK, Josselyn NJ, Hwuang E, Swago S, Keeney SJ, Castillero E, Ferrari G, Pilla JJ, Gorman JH, Gorman RC, Tschabrunn C, Shou H, Matthai W, Wehrli FW, Ferrari VA, Han Y, Litt H, Witschey WR. Magnetic susceptibility and R2* of myocardial reperfusion injury at 3T and 7T. Magn Reson Med 2022; 87:323-336. [PMID: 34355815 PMCID: PMC9067599 DOI: 10.1002/mrm.28955] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 07/15/2021] [Accepted: 07/17/2021] [Indexed: 01/03/2023]
Abstract
PURPOSE Magnetic susceptibility (Δχ) alterations have shown association with myocardial infarction (MI) iron deposition, yet there remains limited understanding of the relationship between relaxation rates and susceptibility or the effect of magnetic field strength. Hence, Δχ and R 2 ∗ in MI were compared at 3T and 7T. METHODS Subacute MI was induced by coronary artery ligation in male Yorkshire swine. 3D multiecho gradient echo imaging was performed at 1-week postinfarction at 3T and 7T. Quantitative susceptibility mapping images were reconstructed using a morphology-enabled dipole inversion. R 2 ∗ maps and quantitative susceptibility mapping were generated to assess the relationship between R 2 ∗ , Δχ, and field strength. Infarct histopathology was investigated. RESULTS Magnetic susceptibility was not significantly different across field strengths (7T: 126.8 ± 41.7 ppb; 3T: 110.2 ± 21.0 ppb, P = NS), unlike R 2 ∗ (7T: 247.0 ± 14.8 Hz; 3T: 106.1 ± 6.5 Hz, P < .001). Additionally, infarct Δχ and R 2 ∗ were significantly higher than remote myocardium. Magnetic susceptibility at 7T versus 3T had a significant association (β = 1.02, R2 = 0.82, P < .001), as did R 2 ∗ (β = 2.35, R2 = 0.98, P < .001). Infarct pathophysiology and iron deposition were detected through histology and compared with imaging findings. CONCLUSION R 2 ∗ showed dependence and Δχ showed independence of field strength. Histology validated the presence of iron and supported imaging findings.
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Affiliation(s)
- Brianna F. Moon
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Srikant Kamesh Iyer
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Nicholas J. Josselyn
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Eileen Hwuang
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Sophia Swago
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Samuel J. Keeney
- Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Department of Pediatrics, Children’s Hospital of Philadelphia, Philadelphia, PA, USA
| | - Estibaliz Castillero
- Department of Surgery, Columbia University Irving Medical Center, New York City, NY, USA
| | - Giovanni Ferrari
- Department of Surgery, Columbia University Irving Medical Center, New York City, NY, USA
| | - James J. Pilla
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Joseph H. Gorman
- Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Robert C. Gorman
- Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Cory Tschabrunn
- Department of Medicine, Division of Cardiovascular Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Haochang Shou
- Department of Biostatistics, Epidemiology and Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - William Matthai
- Department of Medicine, Penn Presbyterian Medical Center, University of Pennsylvania, Philadelphia, PA, USA
| | - Felix W. Wehrli
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Victor A. Ferrari
- Department of Medicine, Division of Cardiovascular Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Yuchi Han
- Department of Medicine, Division of Cardiovascular Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Harold Litt
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Department of Medicine, Division of Cardiovascular Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Walter R. Witschey
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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11
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Imai A, Khamooshian A, Okamoto K, Saito Y, Wijdh-den Hamer IJ, Mariani MA, Gillespie MJ, Gorman RC, Gorman JH, Bouma W. Left atrial geometry in an ovine ischemic mitral regurgitation model: implications for transcatheter mitral valve replacement devices with a left atrial anchoring mechanism. J Cardiothorac Surg 2021; 16:295. [PMID: 34629098 PMCID: PMC8504054 DOI: 10.1186/s13019-021-01654-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 09/20/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Transcatheter mitral valve replacement (TMVR) is a challenging, but promising minimally invasive treatment option for patients with mitral valve disease. Depending on the anchoring mechanism, complications such as mitral leaflet or chordal disruption, aortic valve disruption or left ventricular outflow tract obstruction may occur. Supra-annular devices only anchor at the left atrial (LA) level with a low risk of these complications. For development of transcatheter valves based on LA anchoring, animal feasibility studies are required. In this study we sought to describe LA systolic and diastolic geometry in an ovine ischemic mitral regurgitation (IMR) model using magnetic resonance imaging (MRI) and echocardiography in order to facilitate future research focusing on TMVR device development for (I)MR with LA anchoring mechanisms. METHODS A group of 10 adult male Dorsett sheep underwent a left lateral thoracotomy. Posterolateral myocardial infarction was created by ligation of the left circumflex coronary artery, the obtuse marginal and diagonal branches. MRI and echocardiography were performed at baseline and 8 weeks after myocardial infarction (MI). RESULTS Six animals survived to 8 weeks follow-up. All animals had grade 2 + or higher IMR 8 weeks post-MI. All LA geometric parameters did not change significantly 8 weeks post-MI compared to baseline. Diastolic and systolic interpapillary muscle distance increased significantly 8 weeks post-MI. CONCLUSIONS Systolic and diastolic LA geometry do not change significantly in the presence of grade 2 + or higher IMR 8 weeks post-MI. These findings help facilitate future tailored TMVR device development with LA anchoring mechanisms.
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Affiliation(s)
- Akito Imai
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, PA, USA.,Department of Cardiovascular Surgery, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Arash Khamooshian
- Department of Cardiothoracic Surgery, University Medical Center Groningen, University of Groningen, Hanzeplein 1, P.O. Box 30001, 9700 RB, Groningen, The Netherlands
| | - Keitaro Okamoto
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, PA, USA.,Department of Cardiovascular Surgery, Oita University, Oita, Japan
| | - Yoshiaki Saito
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, PA, USA.,Department of Thoracic and Cardiovascular Surgery, Hirosaki University School of Medicine, Hirosaki, Japan
| | | | - Massimo A Mariani
- Department of Cardiovascular Surgery, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Matthew J Gillespie
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, PA, USA.,Department of Pediatrics, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA, USA
| | - Robert C Gorman
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, PA, USA.,Department of Surgery, University of Pennsylvania, Philadelphia, PA, USA
| | - Joseph H Gorman
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, PA, USA.,Onocor LLC, Philadelphia, PA, USA
| | - Wobbe Bouma
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, PA, USA. .,Department of Cardiothoracic Surgery, University Medical Center Groningen, University of Groningen, Hanzeplein 1, P.O. Box 30001, 9700 RB, Groningen, The Netherlands.
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12
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Pouch AM, Patel PA, Desai ND, Yushkevich N, Goodwin M, Lai EK, Cheung AT, Moeller P, Weiss SJ, Gorman JH, Bavaria JE, Gorman RC. Dynamic Volumetric Assessment of the Aortic Root: The Influence of Bicuspid Aortic Valve Competence. Ann Thorac Surg 2021; 112:1317-1324. [PMID: 32987018 PMCID: PMC7990744 DOI: 10.1016/j.athoracsur.2020.07.036] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 07/13/2020] [Accepted: 07/20/2020] [Indexed: 11/20/2022]
Abstract
BACKGROUND Aortic root evaluation is conventionally based on 2-dimensional measurements at a single phase of the cardiac cycle. This work presents an image analysis method for assessing dynamic 3-dimensional changes in the aortic root of minimally calcified bicuspid aortic valves (BAVs) with and without moderate to severe aortic regurgitation. METHODS The aortic root was segmented over the full cardiac cycle in 3-dimensional transesophageal echocardiographic images acquired from 19 patients with minimally calcified BAVs and from 16 patients with physiologically normal tricuspid aortic valves (TAVs). The size and dynamics of the aortic root were assessed using the following image-derived measurements: absolute mean root volume and mean area at the level of the ventriculoaortic junction, sinuses of Valsalva, and sinotubular junction, as well as normalized root volume change and normalized area change of the ventriculoaortic junction, sinuses of Valsalva, and sinotubular junction over the cardiac cycle. RESULTS Normalized volume change over the cardiac cycle was significantly greater in BAV roots with moderate to severe regurgitation than in normal TAV roots and in BAV roots with no or mild regurgitation. Aortic root dynamics were most significantly different at the mid-level of the sinuses of Valsalva in BAVs with moderate to severe regurgitation than in competent TAVs and BAVs. CONCLUSIONS Echocardiographic reconstruction of the aortic root demonstrates significant differences in dynamics of BAV roots with moderate to severe regurgitation relative to physiologically normal TAVs and competent BAVs. This finding may have implications for risk of future dilatation, dissection, or rupture, which warrant further investigation.
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Affiliation(s)
- Alison M Pouch
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania; Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania.
| | - Prakash A Patel
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Nimesh D Desai
- Division of Cardiovascular Surgery, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Natalie Yushkevich
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Michael Goodwin
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Eric K Lai
- Division of Cardiovascular Surgery, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Albert T Cheung
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University, Stanford, California
| | - Patrick Moeller
- Division of Cardiovascular Surgery, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Stuart J Weiss
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Joseph H Gorman
- Division of Cardiovascular Surgery, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Joseph E Bavaria
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Robert C Gorman
- Division of Cardiovascular Surgery, University of Pennsylvania, Philadelphia, Pennsylvania
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13
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Pasrija C, Quinn R, Ghoreishi M, Eperjesi T, Lai E, Gorman RC, Gorman JH, Gorman RC, Pouch A, Cortez FV, D'Ambra MN, Gammie JS. A Novel Quantitative Ex Vivo Model of Functional Mitral Regurgitation. Innovations (Phila) 2021; 15:329-337. [PMID: 32830572 DOI: 10.1177/1556984520930336] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
OBJECTIVE Durability of mitral valve (MV) repair for functional mitral regurgitation (FMR) remains suboptimal. We sought to create a highly reproducible, quantitative ex vivo model of FMR that functions as a platform to test novel repair techniques. METHODS Fresh swine hearts (n = 10) were pressurized with air to a left ventricular pressure of 120 mmHg. The left atrium was excised and the altered geometry of FMR was created by radially dilating the annulus and displacing the papillary muscle tips apically and radially in a calibrated fashion. This was continued in a graduated fashion until coaptation was exhausted. Imaging of the MV was performed with a 3-dimensional (3D) structured-light scanner, which records 3D structure, texture, and color. The model was validated using transesophageal echocardiography in patients with normal MVs and severe FMR. RESULTS Compared to controls, the anteroposterior diameter in the FMR state increased 32% and the annular area increased 35% (P < 0.001). While the anterior annular circumference remained fixed, the posterior circumference increased by 20% (P = 0.026). The annulus became more planar and the tenting height increased 56% (9 to 14 mm, P < 0.001). The median coaptation depth significantly decreased (anterior leaflet: 5 vs 2 mm; posterior leaflet: 7 vs 3 mm, P < 0.001). The ex vivo normal and FMR models had similar characteristics as clinical controls and patients with severe FMR. CONCLUSIONS This novel quantitative ex vivo model provides a simple, reproducible, and inexpensive benchtop representation of FMR that mimics the systolic valvular changes of patients with FMR.
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Affiliation(s)
- Chetan Pasrija
- 12264 Division of Cardiac Surgery, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Rachael Quinn
- 12264 Division of Cardiac Surgery, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Mehrdad Ghoreishi
- 12264 Division of Cardiac Surgery, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Thomas Eperjesi
- 6572 Department of Surgery, University of Pennsylvania, PA, USA
| | - Eric Lai
- 6572 Department of Surgery, University of Pennsylvania, PA, USA
| | - Robert C Gorman
- 6572 Department of Surgery, University of Pennsylvania, PA, USA
| | - Joseph H Gorman
- 6572 Department of Surgery, University of Pennsylvania, PA, USA
| | - Robert C Gorman
- 6572 Department of Surgery, University of Pennsylvania, PA, USA
| | - Alison Pouch
- 6572 Department of Surgery, University of Pennsylvania, PA, USA
| | - Felino V Cortez
- 12264 Division of Cardiac Surgery, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Michael N D'Ambra
- 12264 Division of Cardiac Surgery, University of Maryland School of Medicine, Baltimore, MD, USA
| | - James S Gammie
- 12264 Division of Cardiac Surgery, University of Maryland School of Medicine, Baltimore, MD, USA
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14
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Liu H, Soares JS, Walmsley J, Li DS, Raut S, Avazmohammadi R, Iaizzo P, Palmer M, Gorman JH, Gorman RC, Sacks MS. The impact of myocardial compressibility on organ-level simulations of the normal and infarcted heart. Sci Rep 2021; 11:13466. [PMID: 34188138 PMCID: PMC8242073 DOI: 10.1038/s41598-021-92810-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 05/25/2021] [Indexed: 11/09/2022] Open
Abstract
Myocardial infarction (MI) rapidly impairs cardiac contractile function and instigates maladaptive remodeling leading to heart failure. Patient-specific models are a maturing technology for developing and determining therapeutic modalities for MI that require accurate descriptions of myocardial mechanics. While substantial tissue volume reductions of 15-20% during systole have been reported, myocardium is commonly modeled as incompressible. We developed a myocardial model to simulate experimentally-observed systolic volume reductions in an ovine model of MI. Sheep-specific simulations of the cardiac cycle were performed using both incompressible and compressible tissue material models, and with synchronous or measurement-guided contraction. The compressible tissue model with measurement-guided contraction gave best agreement with experimentally measured reductions in tissue volume at peak systole, ventricular kinematics, and wall thickness changes. The incompressible model predicted myofiber peak contractile stresses approximately double the compressible model (182.8 kPa, 107.4 kPa respectively). Compensatory changes in remaining normal myocardium with MI present required less increase of contractile stress in the compressible model than the incompressible model (32.1%, 53.5%, respectively). The compressible model therefore provided more accurate representation of ventricular kinematics and potentially more realistic computed active contraction levels in the simulated infarcted heart. Our findings suggest that myocardial compressibility should be incorporated into future cardiac models for improved accuracy.
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Affiliation(s)
- Hao Liu
- James T. Willerson Center for Cardiovascular Modeling and Simulation, The University of Texas at Austin, Austin, TX, USA
| | - João S Soares
- Engineered Tissue Multiscale Mechanics and Modeling Laboratory, Virginia Commonwealth University, Richmond, VA, USA
| | - John Walmsley
- James T. Willerson Center for Cardiovascular Modeling and Simulation, The University of Texas at Austin, Austin, TX, USA
| | - David S Li
- James T. Willerson Center for Cardiovascular Modeling and Simulation, The University of Texas at Austin, Austin, TX, USA
| | - Samarth Raut
- James T. Willerson Center for Cardiovascular Modeling and Simulation, The University of Texas at Austin, Austin, TX, USA
| | - Reza Avazmohammadi
- Computational Cardiovascular Bioengineering Lab, Texas A&M University, College Station, TX, USA
| | - Paul Iaizzo
- Visible Heart Lab, University of Minnesota Twin Cities, Minneapolis, MN, USA
| | - Mark Palmer
- Corporate Core Technologies, Medtronic, Inc., Minneapolis, USA
| | - Joseph H Gorman
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, PA, USA
| | - Robert C Gorman
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, PA, USA
| | - Michael S Sacks
- James T. Willerson Center for Cardiovascular Modeling and Simulation, The University of Texas at Austin, Austin, TX, USA.
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15
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Castillero E, Howsmon DP, Rego BV, Keeney SJ, Driesbaugh KH, Kawashima T, Xue (薛应騛) Y, Camillo C, George I, Gorman RC, Gorman JH, Sacks MS, Levy RJ, Ferrari G. Altered Responsiveness to TGFβ and BMP and Increased CD45+ Cell Presence in Mitral Valves Are Unique Features of Ischemic Mitral Regurgitation. Arterioscler Thromb Vasc Biol 2021; 41:2049-2062. [PMID: 33827255 DOI: 10.1161/atvbaha.121.316111] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Estibaliz Castillero
- Department of Surgery, Columbia University Irving Medical Center, New York, NY (E.C., Y.X., C.C., I.G., G.F.)
| | - Daniel P Howsmon
- Department of Biomedical Engineering, James T. Willerson Center for Cardiovascular Modeling and Simulation, Oden Institute for Computational Engineering and Sciences, The University of Texas at Austin (D.P.H., B.V.R., M.S.S.)
| | - Bruno V Rego
- Department of Biomedical Engineering, James T. Willerson Center for Cardiovascular Modeling and Simulation, Oden Institute for Computational Engineering and Sciences, The University of Texas at Austin (D.P.H., B.V.R., M.S.S.)
| | - Samuel J Keeney
- Department of Pediatrics, Children's Hospital of Philadelphia, PA (S.J.K., K.H.D., R.J.L.)
| | - Kathryn H Driesbaugh
- Department of Pediatrics, Children's Hospital of Philadelphia, PA (S.J.K., K.H.D., R.J.L.)
| | - Takayuki Kawashima
- Gorman Cardiovascular Research Group, Department of Surgery, Smilow Center for Translational Research, Perelman School of Medicine, University of Pennsylvania, Philadelphia (T.K., R.C.G., J.H.G.)
| | - Yingfei Xue (薛应騛)
- Department of Surgery, Columbia University Irving Medical Center, New York, NY (E.C., Y.X., C.C., I.G., G.F.)
| | - Chiara Camillo
- Department of Surgery, Columbia University Irving Medical Center, New York, NY (E.C., Y.X., C.C., I.G., G.F.)
| | - Isaac George
- Department of Surgery, Columbia University Irving Medical Center, New York, NY (E.C., Y.X., C.C., I.G., G.F.)
| | - Robert C Gorman
- Gorman Cardiovascular Research Group, Department of Surgery, Smilow Center for Translational Research, Perelman School of Medicine, University of Pennsylvania, Philadelphia (T.K., R.C.G., J.H.G.)
| | - Joseph H Gorman
- Gorman Cardiovascular Research Group, Department of Surgery, Smilow Center for Translational Research, Perelman School of Medicine, University of Pennsylvania, Philadelphia (T.K., R.C.G., J.H.G.)
| | - Michael S Sacks
- Department of Biomedical Engineering, James T. Willerson Center for Cardiovascular Modeling and Simulation, Oden Institute for Computational Engineering and Sciences, The University of Texas at Austin (D.P.H., B.V.R., M.S.S.)
| | - Robert J Levy
- Department of Pediatrics, Children's Hospital of Philadelphia, PA (S.J.K., K.H.D., R.J.L.)
| | - Giovanni Ferrari
- Department of Surgery, Columbia University Irving Medical Center, New York, NY (E.C., Y.X., C.C., I.G., G.F.)
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16
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Aly AH, Saito Y, Bouma W, Pilla JJ, Pouch AM, Yushkevich PA, Gillespie MJ, Gorman JH, Gorman RC. Multimodal image analysis and subvalvular dynamics in ischemic mitral regurgitation. JTCVS Open 2021; 5:48-60. [PMID: 36003177 PMCID: PMC9390375 DOI: 10.1016/j.xjon.2020.10.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 10/09/2020] [Indexed: 11/15/2022]
Affiliation(s)
- Ahmed H. Aly
- Gorman Cardiovascular Research Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pa
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pa
| | - Yoshiaki Saito
- Gorman Cardiovascular Research Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pa
- Department of Thoracic and Cardiovascular Surgery, Hirosaki University, Aomori, Japan
| | - Wobbe Bouma
- Department of Cardiothoracic Surgery, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - James J. Pilla
- Gorman Cardiovascular Research Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pa
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pa
| | - Alison M. Pouch
- Gorman Cardiovascular Research Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pa
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pa
| | - Paul A. Yushkevich
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pa
| | - Matthew J. Gillespie
- Gorman Cardiovascular Research Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pa
- Department of Cardiology, The Children's Hospital of Philadelphia, Philadelphia, Pa
| | - Joseph H. Gorman
- Gorman Cardiovascular Research Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pa
- Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pa
| | - Robert C. Gorman
- Gorman Cardiovascular Research Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pa
- Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pa
- Address for reprints: Robert C. Gorman, MD, Gorman Cardiovascular Research Group, Smilow Center for Translational Research, 3400 Civic Center Blvd, Bldg 421, 11th Floor, Room 114, Philadelphia, PA, 19104-5156.
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17
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Aly AH, Aly AH, Lai EK, Yushkevich N, Stoffers RH, Gorman JH, Cheung AT, Gorman JH, Gorman RC, Yushkevich PA, Pouch AM. In Vivo Image-Based 4D Modeling of Competent and Regurgitant Mitral Valve Dynamics. Exp Mech 2021; 61:159-169. [PMID: 33776070 PMCID: PMC7988343 DOI: 10.1007/s11340-020-00656-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 08/05/2020] [Indexed: 06/12/2023]
Abstract
BACKGROUND In vivo characterization of mitral valve dynamics relies on image analysis algorithms that accurately reconstruct valve morphology and motion from clinical images. The goal of such algorithms is to provide patient-specific descriptions of both competent and regurgitant mitral valves, which can be used as input to biomechanical analyses and provide insights into the pathophysiology of diseases like ischemic mitral regurgitation (IMR). OBJECTIVE The goal is to generate accurate image-based representations of valve dynamics that visually and quantitatively capture normal and pathological valve function. METHODS We present a novel framework for 4D segmentation and geometric modeling of the mitral valve in real-time 3D echocardiography (rt-3DE), an imaging modality used for pre-operative surgical planning of mitral interventions. The framework integrates groupwise multi-atlas label fusion and template-based medial modeling with Kalman filtering to generate quantitatively descriptive and temporally consistent models of valve dynamics. RESULTS The algorithm is evaluated on rt-3DE data series from 28 patients: 14 with normal mitral valve morphology and 14 with severe IMR. In these 28 data series that total 613 individual 3DE images, each 3D mitral valve segmentation is validated against manual tracing, and temporal consistency between segmentations is demonstrated. CONCLUSIONS Automated 4D image analysis allows for reliable non-invasive modeling of the mitral valve over the cardiac cycle for comparison of annular and leaflet dynamics in pathological and normal mitral valves. Future studies can apply this algorithm to cardiovascular mechanics applications, including patient-specific strain estimation, fluid dynamics simulation, inverse finite element analysis, and risk stratification for surgical treatment.
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Affiliation(s)
- A H Aly
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - A H Aly
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - E K Lai
- Gorman Cardiovascular Research Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - N Yushkevich
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | | | - J H Gorman
- Gorman Cardiovascular Research Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - A T Cheung
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University Medical Center, Stanford, CA, USA
| | - J H Gorman
- Gorman Cardiovascular Research Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - R C Gorman
- Gorman Cardiovascular Research Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - P A Yushkevich
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - A M Pouch
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
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Contijoch F, Han Y, Kamesh Iyer S, Kellman P, Gualtieri G, Elliott MA, Berisha S, Gorman JH, Gorman RC, Pilla JJ, Witschey WRT. Closed-loop control of k-space sampling via physiologic feedback for cine MRI. PLoS One 2020; 15:e0244286. [PMID: 33373391 PMCID: PMC7771662 DOI: 10.1371/journal.pone.0244286] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 12/08/2020] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Segmented cine cardiac MRI combines data from multiple heartbeats to achieve high spatiotemporal resolution cardiac images, yet predefined k-space segmentation trajectories can lead to suboptimal k-space sampling. In this work, we developed and evaluated an autonomous and closed-loop control system for radial k-space sampling (ARKS) to increase sampling uniformity. METHODS The closed-loop system autonomously selects radial k-space sampling trajectory during live segmented cine MRI and attempts to optimize angular sampling uniformity by selecting views in regions of k-space that were not previously well-sampled. Sampling uniformity and the ability to detect cardiac phase in vivo was assessed using ECG data acquired from 10 normal subjects in an MRI scanner. The approach was then implemented with a fast gradient echo sequence on a whole-body clinical MRI scanner and imaging was performed in 4 healthy volunteers. The closed-loop k-space trajectory was compared to random, uniformly distributed and golden angle view trajectories via measurement of k-space uniformity and the point spread function. Lastly, an arrhythmic dataset was used to evaluate a potential application of the approach. RESULTS The autonomous trajectory increased k-space sampling uniformity by 15±7%, main lobe point spread function (PSF) signal intensity by 6±4%, and reduced ringing relative to golden angle sampling. When implemented, the autonomous pulse sequence prescribed radial view angles faster than the scan TR (0.98 ± 0.01 ms, maximum = 1.38 ms) and increased k-space sampling mean uniformity by 10±11%, decreased uniformity variability by 44±12%, and increased PSF signal ratio by 6±6% relative to golden angle sampling. CONCLUSION The closed-loop approach enables near-uniform radial sampling in a segmented acquisition approach which was higher than predetermined golden-angle radial sampling. This can be utilized to increase the sampling or decrease the temporal footprint of an acquisition and the closed-loop framework has the potential to be applied to patients with complex heart rhythms.
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Affiliation(s)
- Francisco Contijoch
- Department of Bioengineering, Jacobs School of Engineering, University of California, San Diego, CA, United States of America
- Department of Radiology, School of Medicine, University of California, San Diego, CA, United States of America
| | - Yuchi Han
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States of America
| | - Srikant Kamesh Iyer
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States of America
| | - Peter Kellman
- National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD, United States of America
| | | | - Mark A. Elliott
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States of America
| | - Sebastian Berisha
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States of America
| | - Joseph H. Gorman
- Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States of America
| | - Robert C. Gorman
- Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States of America
| | - James J. Pilla
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States of America
| | - Walter R. T. Witschey
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States of America
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Li DS, Avazmohammadi R, Rodell CB, Hsu EW, Burdick JA, Gorman JH, Gorman RC, Sacks MS. How hydrogel inclusions modulate the local mechanical response in early and fully formed post-infarcted myocardium. Acta Biomater 2020; 114:296-306. [PMID: 32739434 PMCID: PMC7484038 DOI: 10.1016/j.actbio.2020.07.046] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 07/21/2020] [Accepted: 07/23/2020] [Indexed: 11/23/2022]
Abstract
Expansion of myocardium after myocardial infarction (MI) has long been identified as the primary mechanism that drives adverse left ventricular (LV) remodeling towards heart failure and death. Direct injection of hydrogels into the myocardium to mechanically constrain the infarct has demonstrated promise in limiting its remodeling and expansion. Despite early successes, there remain open questions in the determination of optimal hydrogel therapies, key application characteristics for which include injected polymer volume, stiffness, and spatial placement. Addressing these questions is complicated by the substantial variations in infarct type and extent, as well as limited understanding of the underlying mechanisms. Herein, we present an investigation on how hydrogel inclusions affect the effective tissue-level stiffness and strain fields in myocardium using full three-dimensional (3D) finite element simulations at early and late post-MI time points. We calibrated our simulations to triaxial mechanical and structural measurements of cuboidal LV myocardial specimens of post-infarcted myocardium, 0 and 4 weeks post-MI, injected with a dual-crosslinking hyaluronic acid-based hydrogel. Simulations included multiple deformation modes that spanned the anticipated physiological range in order to assess the effects of variations in inclusion size, location, and modulus on tissue-level myocardial mechanics. We observed significant local stiffening in the hydrogel-injected specimens that was highly dependent on the volume and mechanical properties of the injected hydrogel. Simulations revealed that the primary effect of the injections under physiological loading was a reduction in myocardial strain. This result suggests that hydrogel injections reduce infarct expansion by limiting the peak strains over the cardiac cycle. Overall, our study indicated that modulation of local effective tissue stiffness and corresponding strain reduction are governed by the volume and stiffness of the hydrogel, but relatively insensitive to its transmural placement. These findings provide important insights into mechanisms for ameliorating post-MI remodeling, as well as guidance for the future design of post-MI therapies.
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Affiliation(s)
- David S Li
- James T. Willerson Center for Cardiovascular Modeling and Simulation, Oden Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712, USA
| | - Reza Avazmohammadi
- James T. Willerson Center for Cardiovascular Modeling and Simulation, Oden Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712, USA; Department of Biomedical Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Christopher B Rodell
- School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA 19104, USA; Polymeric Biomaterials Laboratory, Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Edward W Hsu
- Preclinical Imaging Core Facility, Department of Biomedical Engineering, University of Utah, Salt Lake City, UT 84112, USA
| | - Jason A Burdick
- Polymeric Biomaterials Laboratory, Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Joseph H Gorman
- Gorman Cardiovascular Research Group, Perelman School of Medicine, Department of Surgery, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Robert C Gorman
- Gorman Cardiovascular Research Group, Perelman School of Medicine, Department of Surgery, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Michael S Sacks
- James T. Willerson Center for Cardiovascular Modeling and Simulation, Oden Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712, USA.
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20
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Meijerink F, Wijdh-den Hamer IJ, Bouma W, Pouch AM, Aly AH, Lai EK, Eperjesi TJ, Acker MA, Yushkevich PA, Hung J, Mariani MA, Khabbaz KR, Gleason TG, Mahmood F, Gorman JH, Gorman RC. Intraoperative post-annuloplasty three-dimensional valve analysis does not predict recurrent ischemic mitral regurgitation. J Cardiothorac Surg 2020; 15:161. [PMID: 32616001 PMCID: PMC7333337 DOI: 10.1186/s13019-020-01138-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 05/04/2020] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND High ischemic mitral regurgitation (IMR) recurrence rates continue to plague IMR repair with undersized ring annuloplasty. We have previously shown that pre-repair three-dimensional echocardiography (3DE) analysis is highly predictive of IMR recurrence. The objective of this study was to determine the quantitative change in 3DE annular and leaflet tethering parameters immediately after repair and to determine if intraoperative post-repair 3DE parameters would be able to predict IMR recurrence 6 months after repair. METHODS Intraoperative pre- and post-repair transesophageal real-time 3DE was performed in 35 patients undergoing undersized ring annuloplasty for IMR. An advanced modeling algorhythm was used to assess 3D annular geometry and regional leaflet tethering. IMR recurrence (≥ grade 2) was assessed with transthoracic echocardiography 6 months after repair. RESULTS Annuloplasty significantly reduced septolateral diameter, commissural width, annular area, and tethering volume and significantly increased all segmental tethering angles (except A2). Intraoperative post-repair annular geometry and leaflet tethering did not differ significantly between patients with recurrent IMR (n = 9) and patients with non-recurrent IMR (n = 26). No intraoperative post-repair predictors of IMR recurrence could be identified. CONCLUSIONS Undersized ring annuloplasty changes mitral geometry acutely, exacerbates leaflet tethering, and generally fixes IMR acutely, but it does not always fix the delicate underlying chronic problem of continued left ventricular dilatation and remodeling. This may explain why pre-repair 3D valve geometry (which reflects chronic left ventricular remodeling) is highly predictive of recurrent IMR, whereas immediate post-repair 3D valve geometry (which does not completely reflect chronic left ventricular remodeling anymore) is not.
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Affiliation(s)
- Frank Meijerink
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, PA, USA.
- Department of Cardiothoracic Surgery, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands.
| | - Inez J Wijdh-den Hamer
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, PA, USA
- Department of Cardiothoracic Surgery, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Wobbe Bouma
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, PA, USA
- Department of Cardiothoracic Surgery, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Alison M Pouch
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, PA, USA
| | - Ahmed H Aly
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, PA, USA
| | - Eric K Lai
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, PA, USA
| | - Thomas J Eperjesi
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, PA, USA
| | - Michael A Acker
- Department of Surgery, University of Pennsylvania, Philadelphia, PA, USA
| | - Paul A Yushkevich
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Judy Hung
- Department of Cardiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Massimo A Mariani
- Department of Cardiothoracic Surgery, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Kamal R Khabbaz
- Department of Cardiothoracic Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Thomas G Gleason
- Department of Cardiothoracic Surgery, University of Pittsburgh, Pittsburgh, PA, USA
| | - Feroze Mahmood
- Department of Anesthesia, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Joseph H Gorman
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, PA, USA
- Department of Surgery, University of Pennsylvania, Philadelphia, PA, USA
| | - Robert C Gorman
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, PA, USA
- Department of Surgery, University of Pennsylvania, Philadelphia, PA, USA
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21
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Moon BF, Iyer SK, Hwuang E, Solomon MP, Hall AT, Kumar R, Josselyn NJ, Higbee-Dempsey EM, Tsourkas A, Imai A, Okamoto K, Saito Y, Pilla JJ, Gorman JH, Gorman RC, Tschabrunn C, Keeney SJ, Castillero E, Ferrari G, Jockusch S, Wehrli FW, Shou H, Ferrari VA, Han Y, Gulhane A, Litt H, Matthai W, Witschey WR. Iron imaging in myocardial infarction reperfusion injury. Nat Commun 2020; 11:3273. [PMID: 32601301 PMCID: PMC7324567 DOI: 10.1038/s41467-020-16923-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Accepted: 05/22/2020] [Indexed: 11/09/2022] Open
Abstract
Restoration of coronary blood flow after a heart attack can cause reperfusion injury potentially leading to impaired cardiac function, adverse tissue remodeling and heart failure. Iron is an essential biometal that may have a pathologic role in this process. There is a clinical need for a precise noninvasive method to detect iron for risk stratification of patients and therapy evaluation. Here, we report that magnetic susceptibility imaging in a large animal model shows an infarct paramagnetic shift associated with duration of coronary artery occlusion and the presence of iron. Iron validation techniques used include histology, immunohistochemistry, spectrometry and spectroscopy. Further mRNA analysis shows upregulation of ferritin and heme oxygenase. While conventional imaging corroborates the findings of iron deposition, magnetic susceptibility imaging has improved sensitivity to iron and mitigates confounding factors such as edema and fibrosis. Myocardial infarction patients receiving reperfusion therapy show magnetic susceptibility changes associated with hypokinetic myocardial wall motion and microvascular obstruction, demonstrating potential for clinical translation.
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Affiliation(s)
- Brianna F Moon
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Srikant Kamesh Iyer
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Eileen Hwuang
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Michael P Solomon
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Anya T Hall
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Rishabh Kumar
- Department of Biophysics, University of Pennsylvania, Philadelphia, PA, USA
| | - Nicholas J Josselyn
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Elizabeth M Higbee-Dempsey
- Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Andrew Tsourkas
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Akito Imai
- Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Keitaro Okamoto
- Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Yoshiaki Saito
- Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - James J Pilla
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Joseph H Gorman
- Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Robert C Gorman
- Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Cory Tschabrunn
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Samuel J Keeney
- Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Estibaliz Castillero
- Department of Surgery, Columbia University Irving Medical Center, New York, NY, USA
| | - Giovanni Ferrari
- Department of Surgery, Columbia University Irving Medical Center, New York, NY, USA
| | | | - Felix W Wehrli
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Haochang Shou
- Department of Biostatistics, Epidemiology and Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Victor A Ferrari
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Yuchi Han
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Avanti Gulhane
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Harold Litt
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - William Matthai
- Department of Medicine, Penn Presbyterian Medical Center, University of Pennsylvania, Philadelphia, PA, USA
| | - Walter R Witschey
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA.
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
- Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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22
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Howsmon DP, Rego BV, Castillero E, Ayoub S, Khalighi AH, Gorman RC, Gorman JH, Ferrari G, Sacks MS. Mitral valve leaflet response to ischaemic mitral regurgitation: from gene expression to tissue remodelling. J R Soc Interface 2020; 17:20200098. [PMID: 32370692 PMCID: PMC7276554 DOI: 10.1098/rsif.2020.0098] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 04/07/2020] [Indexed: 02/06/2023] Open
Abstract
Ischaemic mitral regurgitation (IMR), a frequent complication following myocardial infarction (MI), leads to higher mortality and poor clinical prognosis if untreated. Accumulating evidence suggests that mitral valve (MV) leaflets actively remodel post MI, and this remodelling increases both the severity of IMR and the occurrence of MV repair failures. However, the mechanisms of extracellular matrix maintenance and modulation by MV interstitial cells (MVICs) and their impact on MV leaflet tissue integrity and repair failure remain largely unknown. Herein, we sought to elucidate the multiscale behaviour of IMR-induced MV remodelling using an established ovine model. Leaflet tissue at eight weeks post MI exhibited significant permanent plastic radial deformation, eliminating mechanical anisotropy, accompanied by altered leaflet composition. Interestingly, no changes in effective collagen fibre modulus were observed, with MVICs slightly rounder, at eight weeks post MI. RNA sequencing indicated that YAP-induced genes were elevated at four weeks post MI, indicating elevated mechanotransduction. Genes related to extracellular matrix organization were downregulated at four weeks post MI when IMR occurred. Transcriptomic changes returned to baseline by eight weeks post MI. This multiscale study suggests that IMR induces plastic deformation of the MV with no functional damage to the collagen fibres, providing crucial information for computational simulations of the MV in IMR.
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Affiliation(s)
- Daniel P. Howsmon
- James T. Willerson Center for Cardiovascular Modeling and Simulation, Oden Institute for Computational Engineering and Sciences and the Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, USA
| | - Bruno V. Rego
- James T. Willerson Center for Cardiovascular Modeling and Simulation, Oden Institute for Computational Engineering and Sciences and the Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, USA
| | - Estibaliz Castillero
- Department of Surgery, Columbia University Irving Medical Center, New York, NY, USA
| | - Salma Ayoub
- James T. Willerson Center for Cardiovascular Modeling and Simulation, Oden Institute for Computational Engineering and Sciences and the Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, USA
| | - Amir H. Khalighi
- James T. Willerson Center for Cardiovascular Modeling and Simulation, Oden Institute for Computational Engineering and Sciences and the Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, USA
| | - Robert C. Gorman
- Gorman Cardiovascular Research Group, Smilow Center for Translational Research, Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Joseph H. Gorman
- Gorman Cardiovascular Research Group, Smilow Center for Translational Research, Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Giovanni Ferrari
- Department of Surgery, Columbia University Irving Medical Center, New York, NY, USA
| | - Michael S. Sacks
- James T. Willerson Center for Cardiovascular Modeling and Simulation, Oden Institute for Computational Engineering and Sciences and the Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, USA
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Ncho BE, Pierce EL, Bloodworth CH, Imai A, Okamoto K, Saito Y, Gorman RC, Gorman JH, Yoganathan AP. Optimized mitral annuloplasty ring design reduces loading in the posterior annulus. J Thorac Cardiovasc Surg 2020; 159:1766-1774.e2. [PMID: 31272749 PMCID: PMC6885108 DOI: 10.1016/j.jtcvs.2019.05.048] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 04/26/2019] [Accepted: 05/07/2019] [Indexed: 11/22/2022]
Abstract
OBJECTIVE The study objective was to develop a novel annuloplasty ring with regional flexibility and assess its suture force dynamics in healthy ovine subjects compared with fully rigid or fully flexible rings. METHODS Materially heterogeneous rings were created with rigid anterior and posterior, and flexible commissural segments. These rings were created to match the geometry of the Profile 3D ring (Medtronic, Minneapolis, Minn). Each ring was instrumented with 10 force transducers to measure cyclic suture forces (FC) and undersized annuloplasty was performed in 6 healthy ovine subjects. Each FC was recorded and examined for cardiac cycles reaching a maximum left ventricular pressure of 100, 125, and 150 mm Hg. FC was compared with previously reported values from fully rigid Profile 3D and fully flexible prototype rings. RESULTS Relative to the fully rigid ring, the heterogeneous ring exhibited 48% reduction in FC at its commissural (rigid vs heterogeneous: 1.80 ± 0.94 N vs 0.95 ± 0.52 N; P < .001) and 32% reduction in posterior (1.90 ± 0.92 N vs 1.29 ± 0.91 N; P < .001) regions, but not in its anterior region (2.45 ± 1.21 N vs 2.23 ± 1.22 N; P = .279). Relative to the fully flexible ring, the heterogeneous ring exhibited no significant differences in FC in any region. CONCLUSIONS The reduced FC of the heterogeneous ring relative to the fully rigid ring suggests a promising approach to reduce suture loading while preserving the annular remodeling capability of fully rigid rings. Future studies in diseased subjects are necessary to explore repair effectiveness of this ring.
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Affiliation(s)
- Beatrice E Ncho
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Ga
| | - Eric L Pierce
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Ga
| | - Charles H Bloodworth
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Ga
| | - Akito Imai
- Gorman Cardiovascular Research Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pa
| | - Keitaro Okamoto
- Gorman Cardiovascular Research Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pa
| | - Yoshiaki Saito
- Gorman Cardiovascular Research Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pa
| | - Robert C Gorman
- Gorman Cardiovascular Research Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pa
| | - Joseph H Gorman
- Gorman Cardiovascular Research Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pa
| | - Ajit P Yoganathan
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Ga.
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24
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Li DS, Avazmohammadi R, Merchant SS, Kawamura T, Hsu EW, Gorman JH, Gorman RC, Sacks MS. Insights into the passive mechanical behavior of left ventricular myocardium using a robust constitutive model based on full 3D kinematics. J Mech Behav Biomed Mater 2020; 103:103508. [PMID: 32090941 PMCID: PMC7045908 DOI: 10.1016/j.jmbbm.2019.103508] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2019] [Revised: 09/30/2019] [Accepted: 10/23/2019] [Indexed: 02/06/2023]
Abstract
Myocardium possesses a hierarchical structure that results in complex three-dimensional (3D) mechanical behavior, forming a critical component of ventricular function in health and disease. A wide range of constitutive model forms have been proposed for myocardium since the first planar biaxial studies were performed by Demer and Yin (J. Physiol. 339 (1), 1983). While there have been extensive studies since, none have been based on full 3D kinematic data, nor have they utilized optimal experimental design to estimate constitutive parameters, which may limit their predictive capability. Herein we have applied our novel 3D numerical-experimental methodology (Avazmohammadi et al., Biomechanics Model. Mechanobiol. 2018) to explore the applicability of an orthotropic constitutive model for passive ventricular myocardium (Holzapfel and Ogden, Philos. Trans. R. Soc. Lond.: Math. Phys. Eng. Sci. 367, 2009) by integrating 3D optimal loading paths, spatially varying material structure, and inverse modeling techniques. Our findings indicated that the initial model form was not successful in reproducing all optimal loading paths, due to previously unreported coupling behaviors via shearing of myofibers and extracellular collagen fibers in the myocardium. This observation necessitated extension of the constitutive model by adding two additional terms based on the I8(C) pseudo-invariant in the fiber-normal and sheet-normal directions. The modified model accurately reproduced all optimal loading paths and exhibited improved predictive capabilities. These unique results suggest that more complete constitutive models are required to fully capture the full 3D biomechanical response of left ventricular myocardium. The present approach is thus crucial for improved understanding and performance in cardiac modeling in healthy, diseased, and treatment scenarios.
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Affiliation(s)
- David S Li
- James T. Willerson Center for Cardiovascular Modeling and Simulation, Oden Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Reza Avazmohammadi
- James T. Willerson Center for Cardiovascular Modeling and Simulation, Oden Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Samer S Merchant
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, 84112, USA
| | - Tomonori Kawamura
- Gorman Cardiovascular Research Group, Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Edward W Hsu
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, 84112, USA
| | - Joseph H Gorman
- Gorman Cardiovascular Research Group, Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Robert C Gorman
- Gorman Cardiovascular Research Group, Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Michael S Sacks
- James T. Willerson Center for Cardiovascular Modeling and Simulation, Oden Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, 78712, USA.
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25
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Levack MM, Mecozzi G, Jainandunsing JS, Bouma W, Jassar AS, Pouch AM, Yushkevich PA, Mariani MA, Jackson BM, Gorman JH, Gorman RC. Quantitative three-dimensional echocardiographic analysis of the bicuspid aortic valve and aortic root: A single modality approach. J Card Surg 2019; 35:375-382. [PMID: 31794089 DOI: 10.1111/jocs.14387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Patients with bicuspid aortic valves (BAV) are heterogeneous with regard to patterns of root remodeling and valvular dysfunction. Two-dimensional echocardiography is the standard surveillance modality for patients with aortic valve dysfunction. However, ancillary computed tomography or magnetic resonance imaging is often necessary to characterize associated patterns of aortic root pathology. Conversely, the pairing of three-dimensional (3D) echocardiography with novel quantitative modeling techniques allows for a single modality description of the entire root complex. We sought to determine 3D aortic valve and root geometry with this quantitative approach. METHODS Transesophageal real-time 3D echocardiography was performed in five patients with tricuspid aortic valves (TAV) and in five patients with BAV. No patient had evidence of valvular dysfunction or aortic root pathology. A customized image analysis protocol was used to assess 3D aortic annular, valvular, and root geometry. RESULTS Annular, sinus and sinotubular junction diameters and areas were similar in both groups. Coaptation length and area were higher in the TAV group (7.25 ± 0.98 mm and 298 ± 118 mm2 , respectively) compared to the BAV group (5.67 ± 1.33 mm and 177 ± 43 mm2 ; P = .07 and P = .01). Cusp surface area to annular area, coaptation height, and the sub- and supravalvular tenting indices did not differ significantly between groups. CONCLUSIONS Single modality 3D echocardiography-based modeling allows for a quantitative description of the aortic valve and root geometry. This technique together with novel indices will improve our understanding of normal and pathologic geometry in the BAV population and may help to identify geometric predictors of adverse remodeling and guide tailored surgical therapy.
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Affiliation(s)
- Melissa M Levack
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Gianclaudio Mecozzi
- Department of Cardiothoracic Surgery, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Jayant S Jainandunsing
- Department of Anesthesiology and Pain Medicine, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Wobbe Bouma
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, Pennsylvania.,Department of Cardiothoracic Surgery, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Arminder S Jassar
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, Pennsylvania.,Department of Surgery, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Alison M Pouch
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Paul A Yushkevich
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Massimo A Mariani
- Department of Cardiothoracic Surgery, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Benjamin M Jackson
- Department of Surgery, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Joseph H Gorman
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, Pennsylvania.,Department of Surgery, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Robert C Gorman
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, Pennsylvania.,Department of Surgery, University of Pennsylvania, Philadelphia, Pennsylvania
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26
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Rodell CB, Zhang ZL, Dusaj NN, Oquendo Y, Lee ME, Bouma W, Gorman JH, Burdick JA, Gorman RC. Injectable Shear-Thinning Hydrogels Prevent Ischemic Mitral Regurgitation and Normalize Ventricular Flow Dynamics. Semin Thorac Cardiovasc Surg 2019; 32:445-453. [PMID: 31682905 PMCID: PMC7195238 DOI: 10.1053/j.semtcvs.2019.10.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2019] [Accepted: 10/23/2019] [Indexed: 11/11/2022]
Abstract
Injectable hydrogels are known to attenuate left-ventricular (LV) remodeling following myocardial infarction (MI), dependent on material mechanical properties. The effect of hydrogel injection on ischemic mitral regurgitation (IMR) resultant from LV remodeling remains relatively unexplored. This study uses multiple imaging methods to evaluate the efficacy of injectable hydrogels with tunable modulus to prevent post-MI development of IMR. Posterolateral MI was induced in 20 sheep with subsequent epicardial injection of saline (control (MI); n = 7), soft hydrogel (guest-host crosslinking, modulus <1 kPa, n = 7), or stiff hydrogel (dual-crosslinking, modulus = 41.4 ± 4.3 kPa, n = 6) within the infarct region and 8-week follow-up. IMR and valve geometry were assessed by echocardiography. LV geometry (long-axis dimension, posterior chordae length) and ventricular flow dynamics were assessed by magnetic resonance imaging. IMR developed in MI controls at 8 weeks and was attenuated with hydrogel treatment (IMR grade for MI: 1.86 ± 0.69; guest-host crosslinking: 1.29 ± 1.11; dual-crosslinking: 0.50 ± 0.55, P = 0.02 vs MI). Tethering of the posterior leaflet increased in MI controls, but not with stiff hydrogel treatment. Across cohorts, IMR was correlated with changes in the long-axis dimension (Spearman R = 0.77) and posterior chordae length (Spearman R = 0.64). Intraventricular flow dynamics were highly disturbed in MI controls, but stiff hydrogel treatment normalized flow patterns and reduced the prevalence of large (≥2+ MR, >5 mL) regurgitant volumes. Injectable hydrogels attenuated subvalvular remodeling and leaflet tethering, preventing IMR development and normalizing LV flow dynamics. Hydrogels with a supraphysiological modulus yielded best outcomes.
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Affiliation(s)
- Christopher B. Rodell
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104
- Current affiliation: School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, Pennsylvania 19104
| | - Zhang L. Zhang
- Gorman Cardiovascular Research Group, Department of Surgery, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Neville N. Dusaj
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Yousi Oquendo
- Gorman Cardiovascular Research Group, Department of Surgery, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Madonna E. Lee
- Gorman Cardiovascular Research Group, Department of Surgery, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Wobbe Bouma
- Gorman Cardiovascular Research Group, Department of Surgery, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Joseph H. Gorman
- Gorman Cardiovascular Research Group, Department of Surgery, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Jason A. Burdick
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Robert C. Gorman
- Gorman Cardiovascular Research Group, Department of Surgery, University of Pennsylvania, Philadelphia, Pennsylvania 19104
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27
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Merrill TL, Mitchell JE, Merrill DR, Gorman JH, Gorman RC, Gillespie MJ. Myocardial tissue salvage is correlated with ischemic border region temperature at reperfusion. Catheter Cardiovasc Interv 2019; 96:E593-E601. [PMID: 31478608 DOI: 10.1002/ccd.28480] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 08/20/2019] [Indexed: 11/06/2022]
Abstract
OBJECTIVES Our pilot study investigated the association between region-specific myocardial tissue temperature and tissue salvage using a novel tri-lumen cooling catheter to provide rapid localized cooling directly to the heart in an open-chest porcine model of ischemia-reperfusion. BACKGROUND Therapeutic hypothermia remains a promising strategy to limit reperfusion injury following myocardial ischemia. METHODS Large swine underwent 60 min of coronary occlusion followed by 3 hr of reperfusion. Prior to inducing ischemia, six temperature probes were placed directly on the heart, monitoring myocardial temperatures in different locations. Hemodynamic parameters and core temperature were also collected. Approximately 15 min prior to reperfusion, the cooling catheter was inserted via femoral artery and the distal tip advanced proximal to the occluded coronary vessel under fluoroscopic guidance. Autologous blood was pulled from the animal via femoral sheath and delivered through the central lumen of the cooling catheter, delivering at 50 ml/min, 27°C at the distal tip. Cooling was continued for an additional 25 min after reperfusion followed by a 5-min controlled rewarming. Hearts were excised and assessed for infarct size per area at risk. RESULTS Although cooling catheter performance was consistent throughout the study (38 W), the resulting tissue cooling was not. Our results show a correlation between myocardial tissue salvage and ischemic border region (IBR) temperature at the time of reperfusion (R2 = 0.59, p = 0.027). IBR tissue is the tissue located at the boundary between healthy and ischemic tissues. CONCLUSIONS Our findings suggest that localized, rapid, short-term myocardial tissue cooling has the potential to limit reperfusion injury in humans.
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Affiliation(s)
- Thomas L Merrill
- Department of Mechanical Engineering and Biomedical Engineering, Rowan University, Glassboro, New Jersey.,Catheter Development, Focal Cool, LLC, Mullica Hill, New Jersey
| | | | | | - Joseph H Gorman
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Robert C Gorman
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Matthew J Gillespie
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
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28
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Jang C, Hui S, Zeng X, Cowan AJ, Wang L, Chen L, Morscher RJ, Reyes J, Frezza C, Hwang HY, Imai A, Saito Y, Okamoto K, Vaspoli C, Kasprenski L, Zsido GA, Gorman JH, Gorman RC, Rabinowitz JD. Metabolite Exchange between Mammalian Organs Quantified in Pigs. Cell Metab 2019; 30:594-606.e3. [PMID: 31257152 PMCID: PMC6726553 DOI: 10.1016/j.cmet.2019.06.002] [Citation(s) in RCA: 140] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 04/16/2019] [Accepted: 05/31/2019] [Indexed: 12/30/2022]
Abstract
Mammalian organs continually exchange metabolites via circulation, but systems-level analysis of this shuttling process is lacking. Here, we compared, in fasted pigs, metabolite concentrations in arterial blood versus draining venous blood from 11 organs. Greater than 90% of metabolites showed arterial-venous differences across at least one organ. Surprisingly, the liver and kidneys released not only glucose but also amino acids, both of which were consumed primarily by the intestine and pancreas. The liver and kidneys exhibited additional unexpected activities: liver preferentially burned unsaturated over more atherogenic saturated fatty acids, whereas the kidneys were unique in burning circulating citrate and net oxidizing lactate to pyruvate, thereby contributing to circulating redox homeostasis. Furthermore, we observed more than 700 other cases of tissue-specific metabolite production or consumption, such as release of nucleotides by the spleen and TCA intermediates by pancreas. These data constitute a high-value resource, providing a quantitative atlas of inter-organ metabolite exchange.
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Affiliation(s)
- Cholsoon Jang
- Department of Chemistry and Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Sheng Hui
- Department of Chemistry and Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Xianfeng Zeng
- Department of Chemistry and Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Alexis J Cowan
- Department of Chemistry and Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Lin Wang
- Department of Chemistry and Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Li Chen
- Department of Chemistry and Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Raphael J Morscher
- Department of Chemistry and Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Jorge Reyes
- Department of Chemistry and Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Christian Frezza
- Medical Research Council Cancer Unit, Hutchison/MRC Research Centre, University of Cambridge, Cambridge, UK
| | - Ho Young Hwang
- Perelman School of Medicine, University of Pennsylvania, 3400 Civic Blvd, Philadelphia, PA 19104, USA
| | - Akito Imai
- Perelman School of Medicine, University of Pennsylvania, 3400 Civic Blvd, Philadelphia, PA 19104, USA
| | - Yoshiaki Saito
- Perelman School of Medicine, University of Pennsylvania, 3400 Civic Blvd, Philadelphia, PA 19104, USA
| | - Keitaro Okamoto
- Perelman School of Medicine, University of Pennsylvania, 3400 Civic Blvd, Philadelphia, PA 19104, USA
| | - Christine Vaspoli
- Perelman School of Medicine, University of Pennsylvania, 3400 Civic Blvd, Philadelphia, PA 19104, USA
| | - Loewe Kasprenski
- Perelman School of Medicine, University of Pennsylvania, 3400 Civic Blvd, Philadelphia, PA 19104, USA
| | - Gerald A Zsido
- Perelman School of Medicine, University of Pennsylvania, 3400 Civic Blvd, Philadelphia, PA 19104, USA
| | - Joseph H Gorman
- Perelman School of Medicine, University of Pennsylvania, 3400 Civic Blvd, Philadelphia, PA 19104, USA
| | - Robert C Gorman
- Perelman School of Medicine, University of Pennsylvania, 3400 Civic Blvd, Philadelphia, PA 19104, USA
| | - Joshua D Rabinowitz
- Department of Chemistry and Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA.
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29
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Rodriguez I, Philips BH, Miedel EL, Bright LA, LaTourette PC, Carty AJ, Witschey WR, Gorman RC, Gorman JH, Marx JO. Hydromorphone-induced Neurostimulation in a Yorkshire Swine ( Sus scrofa) after Myocardial Infarction Surgery. J Am Assoc Lab Anim Sci 2019; 58:601-605. [PMID: 31451134 PMCID: PMC6774467 DOI: 10.30802/aalas-jaalas-18-000095] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 10/04/2018] [Accepted: 10/24/2018] [Indexed: 11/05/2022]
Abstract
Opiates play an important role in the control of pain associated with thoracotomy in both people and animals. However, key side effects, including sedation and respiratory depression, could limit the use of opiates in animals that are lethargic due to cardiac disease. In addition, a rare side effect-neuroexcitation resulting in pathologic behavioral changes (seizures, mania, muscle fasciculation)-after the administration of morphine or hydromorphone is well-documented in many species. In pigs, however, these drugs have been shown to stimulate an increase in normal activity. In the case presented, we describe a Yorkshire-cross pig which, after myocardial infarction surgery, went from nonresponsive to alert, responsive, and eating within 30 min of an injection of hydromorphone. This pig was not demonstrating any signs associated with pain at this time, suggesting that the positive response was due to neural stimulation. This case report is the first to describe the use of hydromorphone-a potent, pure μ opiate agonist-for its neurostimulatory effect in pigs with experimentally-induced cardiac disease.
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Affiliation(s)
| | | | - Emily L Miedel
- Department of Comparative Medicine, University of South Florida, Tampa, Florida; and
| | - Lauren A Bright
- Comparative Medicine Resources, Rutgers–The State University of New Jersey, Piscataway, New Jersey
| | - Philip C LaTourette
- University Laboratory Animal Resources
- Department of Pathobiology, School of Veterinary Medicine, and
| | | | | | - Robert C Gorman
- Surgery, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Joseph H Gorman
- Surgery, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - James O Marx
- University Laboratory Animal Resources
- Department of Pathobiology, School of Veterinary Medicine, and
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30
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Hodges MM, Zgheib C, Xu J, Hu J, Dewberry LC, Hilton SA, Allukian MW, Gorman JH, Gorman RC, Liechty KW. Differential Expression of Transforming Growth Factor-β1 Is Associated With Fetal Regeneration After Myocardial Infarction. Ann Thorac Surg 2019; 108:59-66. [PMID: 30690019 DOI: 10.1016/j.athoracsur.2018.12.042] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 11/12/2018] [Accepted: 12/17/2018] [Indexed: 11/16/2022]
Abstract
BACKGROUND Global extracellular matrix (ECM)-related gene expression is decreased after myocardial infarction (MI) in fetal sheep when compared with adult sheep. Transforming growth factor (TGF)-β1 is a key regulator of ECM; therefore we hypothesize that TGF-β1 is differentially expressed in adult and fetal infarcts after MI. METHODS Adult and fetal sheep underwent MI via ligation of the left anterior descending coronary artery. Expression of TGF-β1 and ECM-related genes was evaluated by ovine-specific microarray and quantitative polymerase chain reaction. Fibroblasts from the left ventricle of adult and fetal hearts were treated with TGF-β1 or a TGF-β1 receptor inhibitor (LY36497) to evaluate the effect of TGF-β1 on ECM-related genes. RESULTS Col1a1, col3a1, and MMP9 expression were increased in adult infarcts 3 and 30 days after MI but were upregulated in fetal infarcts only 3 days after MI. Three days after MI elastin expression was increased in adult infarcts. Despite upregulation in adult infarcts both 3 and 30 days after MI, TGF-β1 was not upregulated in fetal infarcts at any time point. Inhibition of the TGF-β1 receptor in adult cardiac fibroblasts decreased expression of col1a1, col3a1, MMP9, elastin, and TIMP1, whereas treatment of fetal cardiac fibroblasts with TGF-β1 increased expression of these genes. CONCLUSIONS TGF-β1 is increased in adult infarcts compared with regenerative, fetal infarcts after MI. Although treatment of fetal cardiac fibroblasts with TGF-β1 conveys an adult phenotype, inhibition of TGF-β1 conveys a fetal phenotype to adult cardiac fibroblasts. Decreasing TGF-β1 after MI may facilitate myocardial regeneration by "fetalizing" the otherwise fibrotic, adult response to MI.
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Affiliation(s)
- Maggie M Hodges
- Laboratory for Fetal and Regenerative Biology, Department of Surgery, University of Colorado Anschutz Medical Campus and Children's Hospital Colorado, Aurora, Colorado.
| | - Carlos Zgheib
- Laboratory for Fetal and Regenerative Biology, Department of Surgery, University of Colorado Anschutz Medical Campus and Children's Hospital Colorado, Aurora, Colorado
| | - Junwang Xu
- Laboratory for Fetal and Regenerative Biology, Department of Surgery, University of Colorado Anschutz Medical Campus and Children's Hospital Colorado, Aurora, Colorado
| | - Junyi Hu
- Laboratory for Fetal and Regenerative Biology, Department of Surgery, University of Colorado Anschutz Medical Campus and Children's Hospital Colorado, Aurora, Colorado
| | - Lindel C Dewberry
- Laboratory for Fetal and Regenerative Biology, Department of Surgery, University of Colorado Anschutz Medical Campus and Children's Hospital Colorado, Aurora, Colorado
| | - Sarah A Hilton
- Laboratory for Fetal and Regenerative Biology, Department of Surgery, University of Colorado Anschutz Medical Campus and Children's Hospital Colorado, Aurora, Colorado
| | - Myron W Allukian
- Department of Pediatric Surgery, The University of Texas Health Science Center at Houston, Houston, Texas
| | - Joseph H Gorman
- Department of Surgery and Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Robert C Gorman
- Department of Surgery and Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Kenneth W Liechty
- Laboratory for Fetal and Regenerative Biology, Department of Surgery, University of Colorado Anschutz Medical Campus and Children's Hospital Colorado, Aurora, Colorado
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31
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Khalighi AH, Rego BV, Drach A, Gorman RC, Gorman JH, Sacks MS. Development of a Functionally Equivalent Model of the Mitral Valve Chordae Tendineae Through Topology Optimization. Ann Biomed Eng 2019; 47:60-74. [PMID: 30187238 PMCID: PMC6516770 DOI: 10.1007/s10439-018-02122-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 08/23/2018] [Indexed: 12/11/2022]
Abstract
Ischemic mitral regurgitation (IMR) is a currently prevalent disease in the US that is projected to become increasingly common as the aging population grows. In recent years, image-based simulations of mitral valve (MV) function have improved significantly, providing new tools to refine IMR treatment. However, clinical implementation of MV simulations has long been hindered as the in vivo MV chordae tendineae (MVCT) geometry cannot be captured with sufficient fidelity for computational modeling. In the current study, we addressed this challenge by developing a method to produce functionally equivalent MVCT models that can be built from the image-based MV leaflet geometry alone. We began our analysis using extant micron-resolution 3D imaging datasets to first build anatomically accurate MV models. We then systematically simplified the native MVCT structure to generate a series of synthetic models by consecutively removing key anatomic features, such as the thickness variations, branching patterns, and chordal origin distributions. In addition, through topology optimization, we identified the minimal structural complexity required to capture the native MVCT behavior. To assess the performance and predictive power of each synthetic model, we analyzed their performance by comparing the mismatch in simulated MV closed shape, as well as the strain and stress tensors, to ground-truth MV models. Interestingly, our results revealed a substantial redundancy in the anatomic structure of native chordal anatomy. We showed that the closing behavior of complete MV apparatus under normal, diseased, and surgically repaired scenarios can be faithfully replicated by a functionally equivalent MVCT model comprised of two representative papillary muscle heads, single strand chords, and a uniform insertion distribution with a density of 15 insertions/cm2. Hence, even though the complete sub-valvular structure is mostly missing in in vivo MV images, we believe our approach will allow for the development of patient-specific complete MV models for surgical repair planning.
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Affiliation(s)
- Amir H Khalighi
- James T. Willerson Center for Cardiovascular Modeling and Simulation, Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, USA
| | - Bruno V Rego
- James T. Willerson Center for Cardiovascular Modeling and Simulation, Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, USA
| | - Andrew Drach
- James T. Willerson Center for Cardiovascular Modeling and Simulation, Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, USA
| | - Robert C Gorman
- Gorman Cardiovascular Research Group, Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Joseph H Gorman
- Gorman Cardiovascular Research Group, Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Michael S Sacks
- James T. Willerson Center for Cardiovascular Modeling and Simulation, Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, USA.
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32
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Rego BV, Khalighi AH, Drach A, Lai EK, Pouch AM, Gorman RC, Gorman JH, Sacks MS. A noninvasive method for the determination of in vivo mitral valve leaflet strains. Int J Numer Method Biomed Eng 2018; 34:e3142. [PMID: 30133180 DOI: 10.1002/cnm.3142] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 06/21/2018] [Accepted: 08/07/2018] [Indexed: 06/08/2023]
Abstract
Assessment of mitral valve (MV) function is important in many diagnostic, prognostic, and surgical planning applications for treatment of MV disease. Yet, to date, there are no accepted noninvasive methods for determination of MV leaflet deformation, which is a critical metric of MV function. In this study, we present a novel, completely noninvasive computational method to estimate MV leaflet in-plane strains from clinical-quality real-time three-dimensional echocardiography (rt-3DE) images. The images were first segmented to produce meshed medial-surface leaflet geometries of the open and closed states. To establish material point correspondence between the two states, an image-based morphing pipeline was implemented within a finite element (FE) modeling framework in which MV closure was simulated by pressurizing the open-state geometry, and local corrective loads were applied to enforce the actual MV closed shape. This resulted in a complete map of local systolic leaflet membrane strains, obtained from the final FE mesh configuration. To validate the method, we utilized an extant in vitro database of fiducially labeled MVs, imaged in conditions mimicking both the healthy and diseased states. Our method estimated local anisotropic in vivo strains with less than 10% error and proved to be robust to changes in boundary conditions similar to those observed in ischemic MV disease. Next, we applied our methodology to ovine MVs imaged in vivo with rt-3DE and compared our results to previously published findings of in vivo MV strains in the same type of animal as measured using surgically sutured fiducial marker arrays. In regions encompassed by fiducial markers, we found no significant differences in circumferential(P = 0.240) or radial (P = 0.808) strain estimates between the marker-based measurements and our novel noninvasive method. This method can thus be used for model validation as well as for studies of MV disease and repair.
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Affiliation(s)
- Bruno V Rego
- Willerson Center for Cardiovascular Modeling and Simulation, Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas
| | - Amir H Khalighi
- Willerson Center for Cardiovascular Modeling and Simulation, Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas
| | - Andrew Drach
- Willerson Center for Cardiovascular Modeling and Simulation, Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas
| | - Eric K Lai
- Gorman Cardiovascular Research Group, Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Alison M Pouch
- Gorman Cardiovascular Research Group, Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Robert C Gorman
- Gorman Cardiovascular Research Group, Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Joseph H Gorman
- Gorman Cardiovascular Research Group, Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Michael S Sacks
- Willerson Center for Cardiovascular Modeling and Simulation, Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas
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Jolley MA, Lasso A, Nam HH, Dinh PV, Scanlan AB, Nguyen AV, Ilina A, Morray B, Glatz AC, McGowan FX, Whitehead K, Dori Y, Gorman JH, Gorman RC, Fichtinger G, Gillespie MJ. Toward predictive modeling of catheter-based pulmonary valve replacement into native right ventricular outflow tracts. Catheter Cardiovasc Interv 2018; 93:E143-E152. [PMID: 30444053 DOI: 10.1002/ccd.27962] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 09/24/2018] [Accepted: 10/15/2018] [Indexed: 02/03/2023]
Abstract
BACKGROUND Pulmonary insufficiency is a consequence of transannular patch repair in Tetralogy of Fallot (ToF) leading to late morbidity and mortality. Transcatheter native outflow tract pulmonary valve replacement has become a reality. However, predicting a secure, atraumatic implantation of a catheter-based device remains a significant challenge due to the complex and dynamic nature of the right ventricular outflow tract (RVOT). We sought to quantify the differences in compression and volume for actual implants, and those predicted by pre-implant modeling. METHODS We used custom software to interactively place virtual transcatheter pulmonary valves (TPVs) into RVOT models created from pre-implant and post Harmony valve implant CT scans of 5 ovine surgical models of TOF to quantify and visualize device volume and compression. RESULTS Virtual device placement visually mimicked actual device placement and allowed for quantification of device volume and radius. On average, simulated proximal and distal device volumes and compression did not vary statistically throughout the cardiac cycle (P = 0.11) but assessment was limited by small sample size. In comparison to actual implants, there was no significant pairwise difference in the proximal third of the device (P > 0.80), but the simulated distal device volume was significantly underestimated relative to actual device implant volume (P = 0.06). CONCLUSIONS This study demonstrates that pre-implant modeling which assumes a rigid vessel wall may not accurately predict the degree of distal RVOT expansion following actual device placement. We suggest the potential for virtual modeling of TPVR to be a useful adjunct to procedural planning, but further development is needed.
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Affiliation(s)
- Matthew A Jolley
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.,Division of Cardiology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Andras Lasso
- Laboratory for Percutaneous Surgery, Queen's University, Kingston, Ontario
| | - Hannah H Nam
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Patrick V Dinh
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Adam B Scanlan
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Alex V Nguyen
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Anna Ilina
- Laboratory for Percutaneous Surgery, Queen's University, Kingston, Ontario
| | - Brian Morray
- Division of Pediatric Cardiology, Seattle Children's Hospital, Seattle, Washington
| | - Andrew C Glatz
- Division of Cardiology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Francis X McGowan
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Kevin Whitehead
- Division of Cardiology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Yoav Dori
- Division of Cardiology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Joseph H Gorman
- Gorman Cardiovascular Research Group, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Robert C Gorman
- Gorman Cardiovascular Research Group, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Gabor Fichtinger
- Laboratory for Percutaneous Surgery, Queen's University, Kingston, Ontario
| | - Matthew J Gillespie
- Division of Cardiology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.,Gorman Cardiovascular Research Group, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
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Wang H, Rodell CB, Zhang X, Dusaj NN, Gorman JH, Pilla JJ, Jackson BM, Burdick JA, Gorman RC, Wenk JF. Effects of hydrogel injection on borderzone contractility post-myocardial infarction. Biomech Model Mechanobiol 2018; 17:1533-1542. [PMID: 29855734 PMCID: PMC10538855 DOI: 10.1007/s10237-018-1039-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Accepted: 05/22/2018] [Indexed: 01/19/2023]
Abstract
Injectable hydrogels are a potential therapy for mitigating adverse left ventricular (LV) remodeling after myocardial infarction (MI). Previous studies using magnetic resonance imaging (MRI) have shown that hydrogel treatment improves systolic strain in the borderzone (BZ) region surrounding the infarct. However, the corresponding contractile properties of the BZ myocardium are still unknown. The goal of the current study was to quantify the in vivo contractile properties of the BZ myocardium post-MI in an ovine model treated with an injectable hydrogel. Contractile properties were determined 8 weeks following posterolateral MI by minimizing the difference between in vivo strains and volume calculated from MRI and finite element model predicted strains and volume. This was accomplished by using a combination of MRI, catheterization, finite element modeling, and numerical optimization. Results show contractility in the BZ of animals treated with hydrogel injection was significantly higher than untreated controls. End-systolic (ES) fiber stress was also greatly reduced in the BZ of treated animals. The passive stiffness of the treated infarct region was found to be greater than the untreated control. Additionally, the wall thickness in the infarct and BZ regions was found to be significantly higher in the treated animals. Treatment with hydrogel injection significantly improved BZ function and reduced LV remodeling, via altered MI properties. These changes are linked to a reduction in the ES fiber stress in the BZ myocardium surrounding the infarct. The current results imply that injectable hydrogels could be a viable therapy for maintaining LV function post-MI.
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Affiliation(s)
- Hua Wang
- Department of Mechanical Engineering, University of Kentucky, 269 Ralph G. Anderson Building, Lexington, KY, 40506-0503, USA
- Department of Mechanical Engineering, Ludong University, Yantai, Shandong, China
| | - Christopher B Rodell
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Xiaoyan Zhang
- Department of Mechanical Engineering, University of Kentucky, 269 Ralph G. Anderson Building, Lexington, KY, 40506-0503, USA
| | - Neville N Dusaj
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Joseph H Gorman
- Gorman Cardiovascular Research Group, Department of Surgery, University of Pennsylvania, Philadelphia, PA, 19104, USA
- Department of Surgery, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - James J Pilla
- Gorman Cardiovascular Research Group, Department of Surgery, University of Pennsylvania, Philadelphia, PA, 19104, USA
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Benjamin M Jackson
- Department of Surgery, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Jason A Burdick
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Robert C Gorman
- Gorman Cardiovascular Research Group, Department of Surgery, University of Pennsylvania, Philadelphia, PA, 19104, USA
- Department of Surgery, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Jonathan F Wenk
- Department of Mechanical Engineering, University of Kentucky, 269 Ralph G. Anderson Building, Lexington, KY, 40506-0503, USA.
- Department of Surgery, University of Kentucky, Lexington, KY, 40506, USA.
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35
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Bouma W, Wijdh-den Hamer IJ, Gorman JH, Gorman RC. Reply. Ann Thorac Surg 2018; 106:313. [PMID: 29432717 DOI: 10.1016/j.athoracsur.2018.01.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/26/2017] [Accepted: 01/06/2018] [Indexed: 10/18/2022]
Affiliation(s)
- Wobbe Bouma
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, Pennsylvania; Department of Cardiothoracic Surgery, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Inez J Wijdh-den Hamer
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, Pennsylvania; Department of Cardiothoracic Surgery, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Joseph H Gorman
- Gorman Cardiovascular Research Group, University of Pennsylvania, 3400 Civic Center Blvd, Philadelphia, PA 19104
| | - Robert C Gorman
- Gorman Cardiovascular Research Group, University of Pennsylvania, 3400 Civic Center Blvd, Philadelphia, PA 19104.
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36
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Avazmohammadi R, Li DS, Leahy T, Shih E, Soares JS, Gorman JH, Gorman RC, Sacks MS. An integrated inverse model-experimental approach to determine soft tissue three-dimensional constitutive parameters: application to post-infarcted myocardium. Biomech Model Mechanobiol 2018; 17:31-53. [PMID: 28861630 PMCID: PMC5809201 DOI: 10.1007/s10237-017-0943-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 07/17/2017] [Indexed: 10/19/2022]
Abstract
Knowledge of the complete three-dimensional (3D) mechanical behavior of soft tissues is essential in understanding their pathophysiology and in developing novel therapies. Despite significant progress made in experimentation and modeling, a complete approach for the full characterization of soft tissue 3D behavior remains elusive. A major challenge is the complex architecture of soft tissues, such as myocardium, which endows them with strongly anisotropic and heterogeneous mechanical properties. Available experimental approaches for quantifying the 3D mechanical behavior of myocardium are limited to preselected planar biaxial and 3D cuboidal shear tests. These approaches fall short in pursuing a model-driven approach that operates over the full kinematic space. To address these limitations, we took the following approach. First, based on a kinematical analysis and using a given strain energy density function (SEDF), we obtained an optimal set of displacement paths based on the full 3D deformation gradient tensor. We then applied this optimal set to obtain novel experimental data from a 1-cm cube of post-infarcted left ventricular myocardium. Next, we developed an inverse finite element (FE) simulation of the experimental configuration embedded in a parameter optimization scheme for estimation of the SEDF parameters. Notable features of this approach include: (i) enhanced determinability and predictive capability of the estimated parameters following an optimal design of experiments, (ii) accurate simulation of the experimental setup and transmural variation of local fiber directions in the FE environment, and (iii) application of all displacement paths to a single specimen to minimize testing time so that tissue viability could be maintained. Our results indicated that, in contrast to the common approach of conducting preselected tests and choosing an SEDF a posteriori, the optimal design of experiments, integrated with a chosen SEDF and full 3D kinematics, leads to a more robust characterization of the mechanical behavior of myocardium and higher predictive capabilities of the SEDF. The methodology proposed and demonstrated herein will ultimately provide a means to reliably predict tissue-level behaviors, thus facilitating organ-level simulations for efficient diagnosis and evaluation of potential treatments. While applied to myocardium, such developments are also applicable to characterization of other types of soft tissues.
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Affiliation(s)
- Reza Avazmohammadi
- Center for Cardiovascular Simulation, Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, 201 East 24th St, Stop C0200, Austin, Texas, 78712-1229, USA
| | - David S Li
- Center for Cardiovascular Simulation, Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, 201 East 24th St, Stop C0200, Austin, Texas, 78712-1229, USA
| | - Thomas Leahy
- Center for Cardiovascular Simulation, Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, 201 East 24th St, Stop C0200, Austin, Texas, 78712-1229, USA
| | - Elizabeth Shih
- Center for Cardiovascular Simulation, Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, 201 East 24th St, Stop C0200, Austin, Texas, 78712-1229, USA
| | - João S Soares
- Center for Cardiovascular Simulation, Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, 201 East 24th St, Stop C0200, Austin, Texas, 78712-1229, USA
| | - Joseph H Gorman
- Gorman Cardiovascular Research Group, Smilow Center for Translational Research, 3400 Civic Center Blvd - Building 421 11th Floor, Room 112, Philadelphia, PA, 19104-5156, USA
| | - Robert C Gorman
- Gorman Cardiovascular Research Group, Smilow Center for Translational Research, 3400 Civic Center Blvd - Building 421 11th Floor, Room 112, Philadelphia, PA, 19104-5156, USA
| | - Michael S Sacks
- Center for Cardiovascular Simulation, Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, 201 East 24th St, Stop C0200, Austin, Texas, 78712-1229, USA.
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Sun L, Hiramatsu Y, Gorman JH, Edmunds LH, Rao AK. Glycoprotein IIb/IIIa Receptor Antagonist Tirofiban Inhibits Thrombin Generation during Cardiopulmonary Bypass in Baboons. Thromb Haemost 2017. [DOI: 10.1055/s-0037-1614643] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
SummaryPlatelets play a major role in coagulation mechanisms and anti-GPIIb-IIIa antibodies inhibit tissue-factor induced thrombin generation in in vitro studies. Tirofiban, a nonpeptide selective glycoprotein (GP) IIb/IIIa antagonist, preserves platelet number and function during cardiopulmonary bypass (CPB) in baboons. We tested the hypothesis that platelet inhibition by tirofiban inhibits thrombin generation in vivo. Four groups of baboons (n = 7-12) were perfused for 60 min; all groups received heparin (300 units/kg). The controls received only heparin. The low dose (0.1 μg/kg/min) and high dose (0.3 μg/kg/min) infusion groups received tirofiban for 60 min before and 60 min during CPB. The bolus plus low dose infusion group received a 15 μg/kg bolus before starting CPB and a low dose infusion (0.1 mg/kg/min) only during CPB. At end of CPB, compared to control group (2.99 ± 0.36 nM), prothrombin fragment F1.2 levels were lower (p <0.05) in low dose infusion group (1.65 ± 0.14 nM, mean ± SE) and high dose infusion group (1.71 ± 0.19 nM), but not bolus plus infusion group (2.69 ± 0.49 nM); they remained significantly lower after protamine administration. At end of CPB, thrombin-antithrombin complex levels were lower in high dose infusion group (40.0 ± 11.2 ng/ml, p <0.05) compared to control group (76.2 ± 7.3 ng/ml). These studies indicate that tirofiban inhibits not only platelet aggregation but also thrombin generation in vivo during CPB, and that this effect is demonstrable even in the presence of intense heparin anticoagulation. They underscore the important inhibitory effect of GPIIb-IIIa antagonists on thrombin generation.
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Wang H, Zhang X, Dorsey SM, McGarvey JR, Campbell KS, Burdick JA, Gorman JH, Pilla JJ, Gorman RC, Wenk JF. Computational Investigation of Transmural Differences in Left Ventricular Contractility. J Biomech Eng 2017; 138:2551744. [PMID: 27591094 DOI: 10.1115/1.4034558] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Indexed: 11/08/2022]
Abstract
Myocardial contractility of the left ventricle (LV) plays an essential role in maintaining normal pump function. A recent ex vivo experimental study showed that cardiomyocyte force generation varies across the three myocardial layers of the LV wall. However, the in vivo distribution of myocardial contractile force is still unclear. The current study was designed to investigate the in vivo transmural distribution of myocardial contractility using a noninvasive computational approach. For this purpose, four cases with different transmural distributions of maximum isometric tension (Tmax) and/or reference sarcomere length (lR) were tested with animal-specific finite element (FE) models, in combination with magnetic resonance imaging (MRI), pressure catheterization, and numerical optimization. Results of the current study showed that the best fit with in vivo MRI-derived deformation was obtained when Tmax assumed different values in the subendocardium, midmyocardium, and subepicardium with transmurally varying lR. These results are consistent with recent ex vivo experimental studies, which showed that the midmyocardium produces more contractile force than the other transmural layers. The systolic strain calculated from the best-fit FE model was in good agreement with MRI data. Therefore, the proposed noninvasive approach has the capability to predict the transmural distribution of myocardial contractility. Moreover, FE models with a nonuniform distribution of myocardial contractility could provide a better representation of LV function and be used to investigate the effects of transmural changes due to heart disease.
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Affiliation(s)
- Hua Wang
- Department of Mechanical Engineering, University of Kentucky, Lexington, KY 40506-0503
| | - Xiaoyan Zhang
- Department of Mechanical Engineering, University of Kentucky, Lexington, KY 40506-0503
| | - Shauna M Dorsey
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104-6321
| | - Jeremy R McGarvey
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, PA 19104-5156;Department of Surgery, University of Pennsylvania, Philadelphia, PA 19104
| | - Kenneth S Campbell
- Department of Physiology, University of Kentucky, Lexington, KY 40536-0298
| | - Jason A Burdick
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104-6321
| | - Joseph H Gorman
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, PA 19104-5156;Department of Surgery, University of Pennsylvania, Philadelphia, PA 19104
| | - James J Pilla
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, PA 19104-5156;Department of Surgery, University of Pennsylvania, Philadelphia, PA 19104;Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104
| | - Robert C Gorman
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, PA 19104-5156;Department of Surgery, University of Pennsylvania, Philadelphia, PA 19104
| | - Jonathan F Wenk
- Department of Mechanical Engineering, University of Kentucky, Lexington, KY 40506-0503;Department of Surgery, University of Kentucky, Lexington, KY 40536-0298 e-mail:
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39
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Rodell CB, Lee ME, Wang H, Takebayashi S, Takayama T, Kawamura T, Arkles JS, Dusaj NN, Dorsey SM, Witschey WRT, Pilla JJ, Gorman JH, Wenk JF, Burdick JA, Gorman RC. Injectable Shear-Thinning Hydrogels for Minimally Invasive Delivery to Infarcted Myocardium to Limit Left Ventricular Remodeling. Circ Cardiovasc Interv 2017; 9:CIRCINTERVENTIONS.116.004058. [PMID: 27729419 DOI: 10.1161/circinterventions.116.004058] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Accepted: 09/07/2016] [Indexed: 12/22/2022]
Abstract
BACKGROUND Injectable, acellular biomaterials hold promise to limit left ventricular remodeling and heart failure precipitated by infarction through bulking or stiffening the infarct region. A material with tunable properties (eg, mechanics, degradation) that can be delivered percutaneously has not yet been demonstrated. Catheter-deliverable soft hydrogels with in vivo stiffening to enhance therapeutic efficacy achieve these requirements. METHODS AND RESULTS We developed a hyaluronic acid hydrogel that uses a tandem crosslinking approach, where the first crosslinking (guest-host) enabled injection and localized retention of a soft (<1 kPa) hydrogel. A second crosslinking reaction (dual-crosslinking) stiffened the hydrogel (41.4±4.3 kPa) after injection. Posterolateral infarcts were investigated in an ovine model (n≥6 per group), with injection of saline (myocardial infarction control), guest-host hydrogels, or dual-crosslinking hydrogels. Computational (day 1), histological (1 day, 8 weeks), morphological, and functional (0, 2, and 8 weeks) outcomes were evaluated. Finite-element modeling projected myofiber stress reduction (>50%; P<0.001) with dual-crosslinking but not guest-host injection. Remodeling, assessed by infarct thickness and left ventricular volume, was mitigated by hydrogel treatment. Ejection fraction was improved, relative to myocardial infarction at 8 weeks, with dual-crosslinking (37% improvement; P=0.014) and guest-host (15% improvement; P=0.058) treatments. Percutaneous delivery via endocardial injection was investigated with fluoroscopic and echocardiographic guidance, with delivery visualized by magnetic resonance imaging. CONCLUSIONS A percutaneous delivered hydrogel system was developed, and hydrogels with increased stiffness were found to be most effective in ameliorating left ventricular remodeling and preserving function. Ultimately, engineered systems such as these have the potential to provide effective clinical options to limit remodeling in patients after infarction.
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Affiliation(s)
- Christopher B Rodell
- From the Department of Bioengineering (C.B.R., N.N.D., S.M.D., J.A.B.), Gorman Cardiovascular Research Group, Department of Surgery (M.E.L., S.T., T.T., T.K., J.S.A., J.H.G., R.C.G.), and Department of Radiology (W.R.T.W., J.J.P.), University of Pennsylvania, Philadelphia; and Department of Mechanical Engineering (H.W., J.F.W.) and Department of Surgery (J.F.W.), University of Kentucky, Lexington
| | - Madonna E Lee
- From the Department of Bioengineering (C.B.R., N.N.D., S.M.D., J.A.B.), Gorman Cardiovascular Research Group, Department of Surgery (M.E.L., S.T., T.T., T.K., J.S.A., J.H.G., R.C.G.), and Department of Radiology (W.R.T.W., J.J.P.), University of Pennsylvania, Philadelphia; and Department of Mechanical Engineering (H.W., J.F.W.) and Department of Surgery (J.F.W.), University of Kentucky, Lexington
| | - Hua Wang
- From the Department of Bioengineering (C.B.R., N.N.D., S.M.D., J.A.B.), Gorman Cardiovascular Research Group, Department of Surgery (M.E.L., S.T., T.T., T.K., J.S.A., J.H.G., R.C.G.), and Department of Radiology (W.R.T.W., J.J.P.), University of Pennsylvania, Philadelphia; and Department of Mechanical Engineering (H.W., J.F.W.) and Department of Surgery (J.F.W.), University of Kentucky, Lexington
| | - Satoshi Takebayashi
- From the Department of Bioengineering (C.B.R., N.N.D., S.M.D., J.A.B.), Gorman Cardiovascular Research Group, Department of Surgery (M.E.L., S.T., T.T., T.K., J.S.A., J.H.G., R.C.G.), and Department of Radiology (W.R.T.W., J.J.P.), University of Pennsylvania, Philadelphia; and Department of Mechanical Engineering (H.W., J.F.W.) and Department of Surgery (J.F.W.), University of Kentucky, Lexington
| | - Tetsushi Takayama
- From the Department of Bioengineering (C.B.R., N.N.D., S.M.D., J.A.B.), Gorman Cardiovascular Research Group, Department of Surgery (M.E.L., S.T., T.T., T.K., J.S.A., J.H.G., R.C.G.), and Department of Radiology (W.R.T.W., J.J.P.), University of Pennsylvania, Philadelphia; and Department of Mechanical Engineering (H.W., J.F.W.) and Department of Surgery (J.F.W.), University of Kentucky, Lexington
| | - Tomonori Kawamura
- From the Department of Bioengineering (C.B.R., N.N.D., S.M.D., J.A.B.), Gorman Cardiovascular Research Group, Department of Surgery (M.E.L., S.T., T.T., T.K., J.S.A., J.H.G., R.C.G.), and Department of Radiology (W.R.T.W., J.J.P.), University of Pennsylvania, Philadelphia; and Department of Mechanical Engineering (H.W., J.F.W.) and Department of Surgery (J.F.W.), University of Kentucky, Lexington
| | - Jeffrey S Arkles
- From the Department of Bioengineering (C.B.R., N.N.D., S.M.D., J.A.B.), Gorman Cardiovascular Research Group, Department of Surgery (M.E.L., S.T., T.T., T.K., J.S.A., J.H.G., R.C.G.), and Department of Radiology (W.R.T.W., J.J.P.), University of Pennsylvania, Philadelphia; and Department of Mechanical Engineering (H.W., J.F.W.) and Department of Surgery (J.F.W.), University of Kentucky, Lexington
| | - Neville N Dusaj
- From the Department of Bioengineering (C.B.R., N.N.D., S.M.D., J.A.B.), Gorman Cardiovascular Research Group, Department of Surgery (M.E.L., S.T., T.T., T.K., J.S.A., J.H.G., R.C.G.), and Department of Radiology (W.R.T.W., J.J.P.), University of Pennsylvania, Philadelphia; and Department of Mechanical Engineering (H.W., J.F.W.) and Department of Surgery (J.F.W.), University of Kentucky, Lexington
| | - Shauna M Dorsey
- From the Department of Bioengineering (C.B.R., N.N.D., S.M.D., J.A.B.), Gorman Cardiovascular Research Group, Department of Surgery (M.E.L., S.T., T.T., T.K., J.S.A., J.H.G., R.C.G.), and Department of Radiology (W.R.T.W., J.J.P.), University of Pennsylvania, Philadelphia; and Department of Mechanical Engineering (H.W., J.F.W.) and Department of Surgery (J.F.W.), University of Kentucky, Lexington
| | - Walter R T Witschey
- From the Department of Bioengineering (C.B.R., N.N.D., S.M.D., J.A.B.), Gorman Cardiovascular Research Group, Department of Surgery (M.E.L., S.T., T.T., T.K., J.S.A., J.H.G., R.C.G.), and Department of Radiology (W.R.T.W., J.J.P.), University of Pennsylvania, Philadelphia; and Department of Mechanical Engineering (H.W., J.F.W.) and Department of Surgery (J.F.W.), University of Kentucky, Lexington
| | - James J Pilla
- From the Department of Bioengineering (C.B.R., N.N.D., S.M.D., J.A.B.), Gorman Cardiovascular Research Group, Department of Surgery (M.E.L., S.T., T.T., T.K., J.S.A., J.H.G., R.C.G.), and Department of Radiology (W.R.T.W., J.J.P.), University of Pennsylvania, Philadelphia; and Department of Mechanical Engineering (H.W., J.F.W.) and Department of Surgery (J.F.W.), University of Kentucky, Lexington
| | - Joseph H Gorman
- From the Department of Bioengineering (C.B.R., N.N.D., S.M.D., J.A.B.), Gorman Cardiovascular Research Group, Department of Surgery (M.E.L., S.T., T.T., T.K., J.S.A., J.H.G., R.C.G.), and Department of Radiology (W.R.T.W., J.J.P.), University of Pennsylvania, Philadelphia; and Department of Mechanical Engineering (H.W., J.F.W.) and Department of Surgery (J.F.W.), University of Kentucky, Lexington
| | - Jonathan F Wenk
- From the Department of Bioengineering (C.B.R., N.N.D., S.M.D., J.A.B.), Gorman Cardiovascular Research Group, Department of Surgery (M.E.L., S.T., T.T., T.K., J.S.A., J.H.G., R.C.G.), and Department of Radiology (W.R.T.W., J.J.P.), University of Pennsylvania, Philadelphia; and Department of Mechanical Engineering (H.W., J.F.W.) and Department of Surgery (J.F.W.), University of Kentucky, Lexington
| | - Jason A Burdick
- From the Department of Bioengineering (C.B.R., N.N.D., S.M.D., J.A.B.), Gorman Cardiovascular Research Group, Department of Surgery (M.E.L., S.T., T.T., T.K., J.S.A., J.H.G., R.C.G.), and Department of Radiology (W.R.T.W., J.J.P.), University of Pennsylvania, Philadelphia; and Department of Mechanical Engineering (H.W., J.F.W.) and Department of Surgery (J.F.W.), University of Kentucky, Lexington.
| | - Robert C Gorman
- From the Department of Bioengineering (C.B.R., N.N.D., S.M.D., J.A.B.), Gorman Cardiovascular Research Group, Department of Surgery (M.E.L., S.T., T.T., T.K., J.S.A., J.H.G., R.C.G.), and Department of Radiology (W.R.T.W., J.J.P.), University of Pennsylvania, Philadelphia; and Department of Mechanical Engineering (H.W., J.F.W.) and Department of Surgery (J.F.W.), University of Kentucky, Lexington.
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Khalighi AH, Drach A, Gorman RC, Gorman JH, Sacks MS. Multi-resolution geometric modeling of the mitral heart valve leaflets. Biomech Model Mechanobiol 2017; 17:351-366. [PMID: 28983742 DOI: 10.1007/s10237-017-0965-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 09/18/2017] [Indexed: 10/18/2022]
Abstract
An essential element of cardiac function, the mitral valve (MV) ensures proper directional blood flow between the left heart chambers. Over the past two decades, computational simulations have made marked advancements toward providing powerful predictive tools to better understand valvular function and improve treatments for MV disease. However, challenges remain in the development of robust means for the quantification and representation of MV leaflet geometry. In this study, we present a novel modeling pipeline to quantitatively characterize and represent MV leaflet surface geometry. Our methodology utilized a two-part additive decomposition of the MV geometric features to decouple the macro-level general leaflet shape descriptors from the leaflet fine-scale features. First, the general shapes of five ovine MV leaflets were modeled using superquadric surfaces. Second, the finer-scale geometric details were captured, quantified, and reconstructed via a 2D Fourier analysis with an additional sparsity constraint. This spectral approach allowed us to easily control the level of geometric details in the reconstructed geometry. The results revealed that our methodology provided a robust and accurate approach to develop MV-specific models with an adjustable level of spatial resolution and geometric detail. Such fully customizable models provide the necessary means to perform computational simulations of the MV at a range of geometric accuracies in order to identify the level of complexity required to achieve predictive MV simulations.
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Affiliation(s)
- Amir H Khalighi
- Center for Cardiovascular Simulation, Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, USA
| | - Andrew Drach
- Center for Cardiovascular Simulation, Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, USA
| | - Robert C Gorman
- Gorman Cardiovascular Research Group, Department of Surgery, University of Pennsylvania, Philadelphia, PA, USA
| | - Joseph H Gorman
- Gorman Cardiovascular Research Group, Department of Surgery, University of Pennsylvania, Philadelphia, PA, USA
| | - Michael S Sacks
- Center for Cardiovascular Simulation, Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, USA.
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Ayoub S, Lee CH, Driesbaugh KH, Anselmo W, Hughes CT, Ferrari G, Gorman RC, Gorman JH, Sacks MS. Regulation of valve interstitial cell homeostasis by mechanical deformation: implications for heart valve disease and surgical repair. J R Soc Interface 2017; 14:20170580. [PMID: 29046338 PMCID: PMC5665836 DOI: 10.1098/rsif.2017.0580] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 09/21/2017] [Indexed: 11/12/2022] Open
Abstract
Mechanical stress is one of the major aetiological factors underlying soft-tissue remodelling, especially for the mitral valve (MV). It has been hypothesized that altered MV tissue stress states lead to deviations from cellular homeostasis, resulting in subsequent cellular activation and extracellular matrix (ECM) remodelling. However, a quantitative link between alterations in the organ-level in vivo state and in vitro-based mechanobiology studies has yet to be made. We thus developed an integrated experimental-computational approach to elucidate MV tissue and interstitial cell responses to varying tissue strain levels. Comprehensive results at different length scales revealed that normal responses are observed only within a defined range of tissue deformations, whereas deformations outside of this range lead to hypo- and hyper-synthetic responses, evidenced by changes in α-smooth muscle actin, type I collagen, and other ECM and cell adhesion molecule regulation. We identified MV interstitial cell deformation as a key player in leaflet tissue homeostatic regulation and, as such, used it as the metric that makes the critical link between in vitro responses to simulated equivalent in vivo behaviour. Results indicated that cell responses have a delimited range of in vivo deformations that maintain a homeostatic response, suggesting that deviations from this range may lead to deleterious tissue remodelling and failure.
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Affiliation(s)
- Salma Ayoub
- Center for Cardiovascular Simulation, Institute for Computational Engineering and Sciences (ICES), Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712, USA
| | - Chung-Hao Lee
- School of Aerospace and Mechanical Engineering, The University of Oklahoma, Norman, OK 73019, USA
| | - Kathryn H Driesbaugh
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Wanda Anselmo
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Connor T Hughes
- Center for Cardiovascular Simulation, Institute for Computational Engineering and Sciences (ICES), Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712, USA
| | - Giovanni Ferrari
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Robert C Gorman
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Joseph H Gorman
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Michael S Sacks
- Center for Cardiovascular Simulation, Institute for Computational Engineering and Sciences (ICES), Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712, USA
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Wang H, Rodell CB, Lee ME, Dusaj NN, Gorman JH, Burdick JA, Gorman RC, Wenk JF. Computational sensitivity investigation of hydrogel injection characteristics for myocardial support. J Biomech 2017; 64:231-235. [PMID: 28888476 DOI: 10.1016/j.jbiomech.2017.08.024] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 07/11/2017] [Accepted: 08/22/2017] [Indexed: 10/18/2022]
Abstract
Biomaterial injection is a potential new therapy for augmenting ventricular mechanics after myocardial infarction (MI). Recent in vivo studies have demonstrated that hydrogel injections can mitigate the adverse remodeling due to MI. More importantly, the material properties of these injections influence the efficacy of the therapy. The goal of the current study is to explore the interrelated effects of injection stiffness and injection volume on diastolic ventricular wall stress and thickness. To achieve this, finite element models were constructed with different hydrogel injection volumes (150µL and 300 µL), where the modulus was assessed over a range of 0.1kPa to 100kPa (based on experimental measurements). The results indicate that a larger injection volume and higher stiffness reduce diastolic myofiber stress the most, by maintaining the wall thickness during loading. Interestingly, the efficacy begins to taper after the hydrogel injection stiffness reaches a value of 50kPa. This computational approach could be used in the future to evaluate the optimal properties of the hydrogel.
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Affiliation(s)
- Hua Wang
- Department of Mechanical Engineering, University of Kentucky, Lexington, KY, United States
| | - Christopher B Rodell
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, United States
| | - Madonna E Lee
- Gorman Cardiovascular Research Group and Department of Surgery, University of Pennsylvania, Philadelphia, PA, United States
| | - Neville N Dusaj
- Departments of Chemistry and Physics, University of Pennsylvania, Philadelphia, PA, United States
| | - Joseph H Gorman
- Gorman Cardiovascular Research Group and Department of Surgery, University of Pennsylvania, Philadelphia, PA, United States
| | - Jason A Burdick
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, United States
| | - Robert C Gorman
- Gorman Cardiovascular Research Group and Department of Surgery, University of Pennsylvania, Philadelphia, PA, United States
| | - Jonathan F Wenk
- Department of Mechanical Engineering, University of Kentucky, Lexington, KY, United States; Department of Surgery, University of Kentucky, Lexington, KY, United States.
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Pierce EL, Bloodworth CH, Siefert AW, Easley TF, Takayama T, Kawamura T, Gorman RC, Gorman JH, Yoganathan AP. Mitral annuloplasty ring suture forces: Impact of surgeon, ring, and use conditions. J Thorac Cardiovasc Surg 2017; 155:131-139.e3. [PMID: 28728784 DOI: 10.1016/j.jtcvs.2017.06.036] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 05/30/2017] [Accepted: 06/15/2017] [Indexed: 10/19/2022]
Abstract
OBJECTIVE The study objective was to quantify the effect of ring type, ring-annulus sizing, suture position, and surgeon on the forces required to tie down and constrain a mitral annuloplasty ring to a beating heart. METHODS Physio (Edwards Lifesciences, Irvine, Calif) or Profile 3D (Medtronic, Dublin, Ireland) annuloplasty rings were instrumented with suture force transducers and implanted in ovine subjects (N = 23). Tie-down forces and cyclic contractile forces were recorded and analyzed at 10 suture positions and at 3 levels of increasing peak left ventricular pressure. RESULTS Across all conditions, tie-down force was 2.7 ± 1.4 N and cyclic contractile force was 2.0 ± 1.2 N. Tie-down force was not meaningfully affected by any factor except surgeon. Significant differences in overall and individual tie-down forces were observed between the 2 primary implanting surgeons. No other factors were observed to significantly affect tie-down force. Contractile suture forces were significantly reduced by ring-annulus true sizing. This was driven almost exclusively by Physio cases and by reduction along the anterior aspect, where dehiscence is less common clinically. Contractile suture forces did not differ significantly between ring types. However, when undersizing, Profile 3D forces were significantly more uniform around the annular circumference. A suture's tie-down force did not correlate to its eventual contractile force. CONCLUSIONS Mitral annuloplasty suture loading is influenced by ring type, ring-annulus sizing, suture position, and surgeon, suggesting that reports of dehiscence may not be merely a series of isolated errors. When compared with forces known to cause suture dehiscence, these in vivo suture loading data aid in establishing potential targets for reducing the occurrence of ring dehiscence.
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Affiliation(s)
- Eric L Pierce
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Ga
| | - Charles H Bloodworth
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Ga
| | - Andrew W Siefert
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Ga; Momentum PMV, Inc, Alpharetta, Ga
| | - Thomas F Easley
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Ga
| | - Tetsushi Takayama
- Gorman Cardiovascular Research Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pa
| | - Tomonori Kawamura
- Gorman Cardiovascular Research Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pa
| | - Robert C Gorman
- Gorman Cardiovascular Research Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pa
| | - Joseph H Gorman
- Gorman Cardiovascular Research Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pa
| | - Ajit P Yoganathan
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Ga.
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Soares JS, Li DS, Lai E, Gorman JH, Gorman RC, Sacks MS. Modeling of Myocardium Compressibility and its Impact in Computational Simulations of the Healthy and Infarcted Heart. Funct Imaging Model Heart 2017; 10263:493-501. [PMID: 31080965 PMCID: PMC6510496 DOI: 10.1007/978-3-319-59448-4_47] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Simulation of heart function requires many components, including accurate descriptions of regional mechanical behavior of the normal and infarcted myocardium. Myocardial compressibility has been known for at least two decades, however its experimental measurement and incorporation into compu-tational simulations has not yet been widely utilized in contemporary cardiac models. In the present work, based on novel in-vivo ovine experimental data, we developed a specialized compressible model that reproduces the peculiar unim-odal compressible behavior of myocardium. Such simulations will be extremely valuable to understand etiology and pathophysiology of myocardium remodeling and its impact on tissue-level properties and organ-level cardiac function.
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Affiliation(s)
- Joao S Soares
- Center for Computational Simulation, Institute for Computational Engineering and Sciences, University of Texas at Austin, Austin, TX, USA
| | - David S Li
- Center for Computational Simulation, Institute for Computational Engineering and Sciences, University of Texas at Austin, Austin, TX, USA
| | - Eric Lai
- Gorman Cardiovascular Research Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Joseph H Gorman
- Gorman Cardiovascular Research Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Robert C Gorman
- Gorman Cardiovascular Research Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Michael S Sacks
- Center for Computational Simulation, Institute for Computational Engineering and Sciences, University of Texas at Austin, Austin, TX, USA
- Gorman Cardiovascular Research Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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Pouch AM, Aly AH, Lasso A, Nguyen AV, Scanlan AB, McGowan FX, Fichtinger G, Gorman RC, Gorman JH, Yushkevich PA, Jolley MA. Image Segmentation and Modeling of the Pediatric Tricuspid Valve in Hypoplastic Left Heart Syndrome. Funct Imaging Model Heart 2017; 10263:95-105. [PMID: 29756127 DOI: 10.1007/978-3-319-59448-4_10] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Hypoplastic left heart syndrome (HLHS) is a single-ventricle congenital heart disease that is fatal if left unpalliated. In HLHS patients, the tricuspid valve is the only functioning atrioventricular valve, and its competence is therefore critical. This work demonstrates the first automated strategy for segmentation, modeling, and morphometry of the tricuspid valve in transthoracic 3D echocardiographic (3DE) images of pediatric patients with HLHS. After initial landmark placement, the automated segmentation step uses multi-atlas label fusion and the modeling approach uses deformable modeling with medial axis representation to produce patient-specific models of the tricuspid valve that can be comprehensively and quantitatively assessed. In a group of 16 pediatric patients, valve segmentation and modeling attains an accuracy (mean boundary displacement) of 0.8 ± 0.2 mm relative to manual tracing and shows consistency in annular and leaflet measurements. In the future, such image-based tools have the potential to improve understanding and evaluation of tricuspid valve morphology in HLHS and guide strategies for patient care.
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Affiliation(s)
- Alison M Pouch
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Ahmed H Aly
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Andras Lasso
- Laboratory for Percutaneous Surgery, Queen's University, Kingston, Canada
| | - Alexander V Nguyen
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Adam B Scanlan
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Francis X McGowan
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Gabor Fichtinger
- Laboratory for Percutaneous Surgery, Queen's University, Kingston, Canada
| | - Robert C Gorman
- Gorman Cardiovascular Research Group, Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Joseph H Gorman
- Gorman Cardiovascular Research Group, Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Paul A Yushkevich
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Matthew A Jolley
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
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Lee CH, Zhang W, Feaver K, Gorman RC, Gorman JH, Sacks MS. On the in vivo function of the mitral heart valve leaflet: insights into tissue-interstitial cell biomechanical coupling. Biomech Model Mechanobiol 2017; 16:1613-1632. [PMID: 28429161 DOI: 10.1007/s10237-017-0908-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 04/07/2017] [Indexed: 10/19/2022]
Abstract
There continues to be a critical need for developing data-informed computational modeling techniques that enable systematic evaluations of mitral valve (MV) function. This is important for a better understanding of MV organ-level biomechanical performance, in vivo functional tissue stresses, and the biosynthetic responses of MV interstitial cells (MVICs) in the normal, pathophysiological, and surgically repaired states. In the present study, we utilized extant ovine MV population-averaged 3D fiducial marker data to quantify the MV anterior leaflet (MVAL) deformations in various kinematic states. This approach allowed us to make the critical connection between the in vivo functional and the in vitro experimental configurations. Moreover, we incorporated the in vivo MVAL deformations and pre-strains into an enhanced inverse finite element modeling framework (Path 1) to estimate the resulting in vivo tissue prestresses [Formula: see text] and the in vivo peak functional tissue stresses [Formula: see text]. These in vivo stress estimates were then cross-verified with the results obtained from an alternative forward modeling method (Path 2), by taking account of the changes in the in vitro and in vivo reference configurations. Moreover, by integrating the tissue-level kinematic results into a downscale MVIC microenvironment FE model, we were able to estimate, for the first time, the in vivo layer-specific MVIC deformations and deformation rates of the normal and surgically repaired MVALs. From these simulations, we determined that the placement of annuloplasty ring greatly reduces the peak MVIC deformation levels in a layer-specific manner. This suggests that the associated reductions in MVIC deformation may down-regulate MV extracellular matrix maintenance, ultimately leading to reduction in tissue mechanical integrity. These simulations provide valuable insight into MV cellular mechanobiology in response to organ- and tissue-level alternations induced by MV disease or surgical repair. They will also assist in the future development of computer simulation tools for guiding MV surgery procedure with enhanced durability and improved long-term surgical outcomes.
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Affiliation(s)
- Chung-Hao Lee
- School of Aerospace and Mechanical Engineering, The University of Oklahoma, 865 Asp Ave., Felgar Hall, Rm. 219C, Norman, OK, 73019, USA.,Department of Biomedical Engineering, Center for Cardiovascular Simulation, Institute for Computational Engineering and Sciences, The University of Texas at Austin, 201 East 24th St, POB 5.236, 1 University Station, C0200, Austin, TX, 78712, USA
| | - Will Zhang
- Department of Biomedical Engineering, Center for Cardiovascular Simulation, Institute for Computational Engineering and Sciences, The University of Texas at Austin, 201 East 24th St, POB 5.236, 1 University Station, C0200, Austin, TX, 78712, USA
| | - Kristen Feaver
- Department of Biomedical Engineering, Center for Cardiovascular Simulation, Institute for Computational Engineering and Sciences, The University of Texas at Austin, 201 East 24th St, POB 5.236, 1 University Station, C0200, Austin, TX, 78712, USA
| | - Robert C Gorman
- Gorman Cardiovascular Research Group, University of Pennsylvania, 3400 Civic Center Blvd, Philadelphia, PA, 19104, USA
| | - Joseph H Gorman
- Gorman Cardiovascular Research Group, University of Pennsylvania, 3400 Civic Center Blvd, Philadelphia, PA, 19104, USA
| | - Michael S Sacks
- Department of Biomedical Engineering, Center for Cardiovascular Simulation, Institute for Computational Engineering and Sciences, The University of Texas at Austin, 201 East 24th St, POB 5.236, 1 University Station, C0200, Austin, TX, 78712, USA. .,W. A. Moncrief, Jr. Simulation-Based Engineering Science Chair I, Department of Biomedical Engineering, Institute for Computational Engineering and Sciences, The University of Texas at Austin, 201 East 24th Street, ACES 5.438, 1 University Station, C0200, Austin, TX, 78712-0027, USA.
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Stoffers RH, Madden M, Shahid M, Contijoch F, Solomon J, Pilla JJ, Gorman JH, Gorman RC, Witschey WRT. Erratum to: Assessment of myocardial injury after reperfused infarction by T1ρ cardiovascular magnetic resonance. J Cardiovasc Magn Reson 2017; 19:42. [PMID: 28347308 PMCID: PMC5368938 DOI: 10.1186/s12968-017-0354-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- Rutger H Stoffers
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, 1 Silverstein 3400 Spruce Street, Philadelphia, PA, 19104, USA
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, PA, USA
| | - Marie Madden
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, 1 Silverstein 3400 Spruce Street, Philadelphia, PA, 19104, USA
| | - Mohammed Shahid
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, 1 Silverstein 3400 Spruce Street, Philadelphia, PA, 19104, USA
| | - Francisco Contijoch
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, PA, USA
| | - Joseph Solomon
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, 1 Silverstein 3400 Spruce Street, Philadelphia, PA, 19104, USA
| | - James J Pilla
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, 1 Silverstein 3400 Spruce Street, Philadelphia, PA, 19104, USA
| | - Joseph H Gorman
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, PA, USA
| | - Robert C Gorman
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, PA, USA
| | - Walter R T Witschey
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, 1 Silverstein 3400 Spruce Street, Philadelphia, PA, 19104, USA.
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Mahmood F, Knio ZO, Yeh L, Amir R, Matyal R, Mashari A, Gorman RC, Gorman JH, Khabbaz KR. Regional Heterogeneity in the Mitral Valve Apparatus in Patients With Ischemic Mitral Regurgitation. Ann Thorac Surg 2017; 103:1171-1177. [PMID: 28274519 DOI: 10.1016/j.athoracsur.2016.11.083] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Revised: 10/17/2016] [Accepted: 11/28/2016] [Indexed: 01/31/2023]
Abstract
BACKGROUND Apical displacement of the coaptation point of the mitral valve (MV) in response to ischemic mitral regurgitation (IMR) represents remodeling of the MV apparatus. Whereas it implies chronicity, it lacks specificity in discriminating normal from a significantly remodeled MV apparatus. Regional aspects of MV remodeling have shown superior value over global remodeling in predicting recurrence after MV repair for IMR. Quite possibly, presence of specific regional changes in MV geometry that are unique to chronic IMR patients could also be used to diagnose the presence and track progression of remodeling. Knowledge of these changes in MV apparatus in patients with IMR can possibly be used to identify patients for surgical intervention before irreversible remodeling occurs. METHODS Three-dimensional transesophageal echocardiographic data were collected from patients who underwent MV surgery for IMR (IMR group, n = 66), and from patients with normal valvular and biventricular function (control group, n = 10). The acquired data of the MV were geometrically analyzed to make regional comparisons between the IMR and the control group to identify measurements that reliably differentiate normal from remodeled MVs. RESULTS Lengthening of the middle potion of the anterior annulus (A2 regional perimeter: 11.149 mm versus 9.798 mm, p = 0.0041), larger nonplanarity angle (147.985 versus 140.720 degrees, p = 0.0459), and increased tenting angle of the posteromedial scallop of the posterior leaflet (P3 tenting angle: 44.354 versus 40.461 degrees, p = 0.0435) were sufficient in differentiating between IMR and the control group. CONCLUSIONS Specific three-dimensional changes in MV geometry can be used to reliably identify a significantly remodeled valve apparatus.
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Affiliation(s)
- Feroze Mahmood
- Department of Anesthesia, Critical Care and Pain Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
| | - Ziyad O Knio
- Department of Surgery, Division of Cardiac Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
| | - Lu Yeh
- Department of Anesthesia, Critical Care and Pain Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts; Department of Anesthesia and Pain Medicine, University of Groningen, University Medical Center, Groningen, Netherlands
| | - Rabia Amir
- Department of Anesthesia, Critical Care and Pain Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
| | - Robina Matyal
- Department of Anesthesia, Critical Care and Pain Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
| | - Azad Mashari
- Department of Anesthesia, Critical Care and Pain Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts; Department of Anesthesia and Pain Management, Toronto General Hospital, University Health Network, University of Toronto, Toronto, Ontario, Canada
| | - Robert C Gorman
- Department of Surgery, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Joseph H Gorman
- Department of Surgery, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Kamal R Khabbaz
- Department of Surgery, Division of Cardiac Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts.
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Stoffers RH, Madden M, Shahid M, Contijoch F, Solomon J, Pilla JJ, Gorman JH, Gorman RC, Witschey WR. Assessment of myocardial injury after reperfused infarction by T1ρ cardiovascular magnetic resonance. J Cardiovasc Magn Reson 2017; 19:17. [PMID: 28196494 PMCID: PMC5310026 DOI: 10.1186/s12968-017-0332-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2016] [Accepted: 01/24/2017] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND The evolution of T1ρ and of other endogenous contrast methods (T2, T1) in the first month after reperfused myocardial infarction (MI) is uncertain. We conducted a study of reperfused MI in pigs to serially monitor T1ρ, T2 and T1 relaxation, scar size and transmurality at 1 and 4 weeks post-MI. METHODS Ten Yorkshire swine underwent 90 min of occlusion of the circumflex artery and reperfusion. T1ρ, T2 and native T1 maps and late gadolinium enhanced (LGE) cardiovascular magnetic resonance (CMR) data were collected at 1 week (n = 10) and 4 weeks (n = 5). Semi-automatic FWHM (full width half maximum) thresholding was used to assess scar size and transmurality and compared to histology. Relaxation times and contrast-to-noise ratio were compared in healthy and remote myocardium at 1 and 4 weeks. Linear regression and Bland-Altman was performed to compare infarct size and transmurality. RESULTS Relaxation time differences between infarcted and remote myocardial tissue were ∆T1 (infarct-remote) = 421.3 ± 108.8 (1 week) and 480.0 ± 33.2 ms (4 week), ∆T1ρ = 68.1 ± 11.6 and 74.3 ± 14.2, and ∆T2 = 51.0 ± 10.1 and 59.2 ± 11.4 ms. Contrast-to-noise ratio was CNRT1 = 7.0 ± 3.5 (1 week) and 6.9 ± 2.4 (4 week), CNRT1ρ = 12.0 ± 6.2 and 12.3 ± 3.2, and CNRT2 = 8.0 ± 3.6 and 10.3 ± 5.8. Infarct size was not significantly different for T1ρ, T1 and T2 compared to LGE (p = 0.14) and significantly decreased from 1 to 4 weeks (p < 0.01). Individual infarct size changes were ∆T1ρ = -3.8%, ∆T1 = -3.5% and ∆LGE = -2.8% from 1 - 4 weeks, but there was no observed change in infarct size for T2 or histologically. CONCLUSIONS T1ρ was highly correlated with alterations left ventricle (LV) pathology at 1 and 4 weeks post-MI and therefore it may be a useful method endogenous contrast imaging of infarction.
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Affiliation(s)
- Rutger H. Stoffers
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, 1 Silverstein 3400 Spruce Street, Philadelphia, PA USA 19104
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, PA USA
| | - Marie Madden
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, 1 Silverstein 3400 Spruce Street, Philadelphia, PA USA 19104
| | - Mohammed Shahid
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, 1 Silverstein 3400 Spruce Street, Philadelphia, PA USA 19104
| | - Francisco Contijoch
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, PA USA
| | - Joseph Solomon
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, 1 Silverstein 3400 Spruce Street, Philadelphia, PA USA 19104
| | - James J. Pilla
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, 1 Silverstein 3400 Spruce Street, Philadelphia, PA USA 19104
| | - Joseph H. Gorman
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, PA USA
| | - Robert C. Gorman
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, PA USA
| | - Walter R.T. Witschey
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, 1 Silverstein 3400 Spruce Street, Philadelphia, PA USA 19104
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Khalighi AH, Drach A, Bloodworth CH, Pierce EL, Yoganathan AP, Gorman RC, Gorman JH, Sacks MS. Mitral Valve Chordae Tendineae: Topological and Geometrical Characterization. Ann Biomed Eng 2017; 45:378-393. [PMID: 27995395 PMCID: PMC7077931 DOI: 10.1007/s10439-016-1775-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2016] [Accepted: 12/07/2016] [Indexed: 01/27/2023]
Abstract
Mitral valve (MV) closure depends upon the proper function of each component of the valve apparatus, which includes the annulus, leaflets, and chordae tendineae (CT). Geometry plays a major role in MV mechanics and thus highly impacts the accuracy of computational models simulating MV function and repair. While the physiological geometry of the leaflets and annulus have been previously investigated, little effort has been made to quantitatively and objectively describe CT geometry. The CT constitute a fibrous tendon-like structure projecting from the papillary muscles (PMs) to the leaflets, thereby evenly distributing the loads placed on the MV during closure. Because CT play a major role in determining the shape and stress state of the MV as a whole, their geometry must be well characterized. In the present work, a novel and comprehensive investigation of MV CT geometry was performed to more fully quantify CT anatomy. In vitro micro-tomography 3D images of ovine MVs were acquired, segmented, then analyzed using a curve-skeleton transform. The resulting data was used to construct B-spline geometric representations of the CT structures, enriched with a continuous field of cross-sectional area (CSA) data. Next, Reeb graph models were developed to analyze overall topological patterns, along with dimensional attributes such as segment lengths, 3D orientations, and CSA. Reeb graph results revealed that the topology of ovine MV CT followed a full binary tree structure. Moreover, individual chords are mostly planar geometries that together form a 3D load-bearing support for the MV leaflets. We further demonstrated that, unlike flow-based branching patterns, while individual CT branches became thinner as they propagated further away from the PM heads towards the leaflets, the total CSA almost doubled. Overall, our findings indicate a certain level of regularity in structure, and suggest that population-based MV CT geometric models can be generated to improve current MV repair procedures.
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Affiliation(s)
- Amir H Khalighi
- Department of Biomedical Engineering, Center for Cardiovascular Simulation, Institute for Computational Engineering and Sciences, The University of Texas at Austin, Austin, TX, USA
| | - Andrew Drach
- Department of Biomedical Engineering, Center for Cardiovascular Simulation, Institute for Computational Engineering and Sciences, The University of Texas at Austin, Austin, TX, USA
| | - Charles H Bloodworth
- Cardiovascular Fluid Mechanics Laboratory, Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | - Eric L Pierce
- Cardiovascular Fluid Mechanics Laboratory, Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | - Ajit P Yoganathan
- Cardiovascular Fluid Mechanics Laboratory, Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | - Robert C Gorman
- Gorman Cardiovascular Research Group, Department of Surgery, University of Pennsylvania, Philadelphia, PA, USA
| | - Joseph H Gorman
- Gorman Cardiovascular Research Group, Department of Surgery, University of Pennsylvania, Philadelphia, PA, USA
| | - Michael S Sacks
- Department of Biomedical Engineering, Center for Cardiovascular Simulation, Institute for Computational Engineering and Sciences, The University of Texas at Austin, Austin, TX, USA.
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