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Machaidze Z, D’Amore A, Freitas RC, Joyce AJ, Bayoumi A, Rich K, Brown DW, Aikawa E, Wagner WR, Sacks MS, Mayer JE. Tissue formation and host remodeling of an elastomeric biodegradable scaffold in an ovine pulmonary leaflet replacement model. J Biomed Mater Res A 2024; 112:276-287. [PMID: 37772456 PMCID: PMC11034854 DOI: 10.1002/jbm.a.37622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 09/01/2023] [Accepted: 09/12/2023] [Indexed: 09/30/2023]
Abstract
In pursuit of a suitable scaffold material for cardiac valve tissue engineering applications, an acellular, electrospun, biodegradable polyester carbonate urethane urea (PECUU) scaffold was evaluated as a pulmonary valve leaflet replacement in vivo. In sheep (n = 8), a single pulmonary valve leaflet was replaced with a PECUU leaflet and followed for 1, 6, and 12 weeks. Implanted leaflet function was assessed in vivo by echocardiography. Explanted samples were studied for gross pathology, microscopic changes in the extracellular matrix, host cellular re-population, and immune responses, and for biomechanical properties. PECUU leaflets showed normal leaflet motion at implant, but decreased leaflet motion and dimensions at 6 weeks. The leaflets accumulated α-SMA and CD45 positive cells, with surfaces covered with endothelial cells (CD31+). New collagen formation occurred (Picrosirius Red). Accumulated tissue thickness correlated with the decrease in leaflet motion. The PECUU scaffolds had histologic evidence of scaffold degradation and an accumulation of pro-inflammatory/M1 and anti-inflammatory/M2 macrophages over time in vivo. The extent of inflammatory cell accumulation correlated with tissue formation and polymer degradation but was also associated with leaflet thickening and decreased leaflet motion. Future studies should explore pre-implant seeding of polymer scaffolds, more advanced polymer fabrication methods able to more closely approximate native tissue structure and function, and other techniques to control and balance the degradation of biomaterials and new tissue formation by modulation of the host immune response.
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Affiliation(s)
- Zurab Machaidze
- Department of Cardiac Surgery, Boston Children’s Hospital, Harvard Medical School. 300 Longwood Ave. Boston, MA. 02115. USA
| | - Antonio D’Amore
- McGowan Institute for Regenerative Medicine. Departments of Surgery and Bioengineering. University of Pittsburgh, 450 Technology Drive. Suite 300. Pittsburgh, PA 15219
- Fondazione RiMED, Via Bandiera 11, 90133 Palermo, Italy
| | - Renata C.C. Freitas
- Department of Cardiac Surgery, Boston Children’s Hospital, Harvard Medical School. 300 Longwood Ave. Boston, MA. 02115. USA
| | - Angelina J. Joyce
- Department of Cardiac Surgery, Boston Children’s Hospital, Harvard Medical School. 300 Longwood Ave. Boston, MA. 02115. USA
| | - Ahmed Bayoumi
- Department of Cardiac Surgery, Boston Children’s Hospital, Harvard Medical School. 300 Longwood Ave. Boston, MA. 02115. USA
| | - Kimberly Rich
- Department of Cardiac Surgery, Boston Children’s Hospital, Harvard Medical School. 300 Longwood Ave. Boston, MA. 02115. USA
| | - David W. Brown
- Department of Cardiology, Boston Children’s Hospital, Harvard Medical School. 300 Longwood Ave. Boston, MA. 02115. USA
| | - Elena Aikawa
- Center for Excellence in Vascular Biology, Brigham and Women’s Hospital, Harvard Medical School. 77 Ave Louis Pasteur, NRB-7, Boston, MA 02115
| | - William R. Wagner
- McGowan Institute for Regenerative Medicine. Departments of Surgery and Bioengineering. University of Pittsburgh, 450 Technology Drive. Suite 300. Pittsburgh, PA 15219
| | - 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 201 East 24th Street, Stop C0200. Austin, TX 78712-1229
| | - John E. Mayer
- Department of Cardiac Surgery, Boston Children’s Hospital, Harvard Medical School. 300 Longwood Ave. Boston, MA. 02115. USA
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Huang J, Zhang W, Jia B, Chen G, Mi Y, Shi Q, Shan Y, Zhang H. A midterm follow-up study of the application of a confluent aortic valve neocuspidization technique with pericardium in children. Transl Pediatr 2023; 12:1981-1991. [PMID: 38130583 PMCID: PMC10730963 DOI: 10.21037/tp-23-289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2023] [Accepted: 10/22/2023] [Indexed: 12/23/2023] Open
Abstract
Background The treatment of aortic valve diseases in children remains a great challenge. We aim to report outcomes and midterm follow-up data of our confluent neocuspidization technique with pericardium for aortic valve replacement (AVR) in children. Methods A retrospective analysis was performed on all 20 children who underwent the confluent neocuspidization technique with pericardium at Children's Hospital of Fudan University from March 2017 to May 2022. Outcome measures included echocardiographic measurements, surgical intervention, and mortality. Results A total of 20 patients (17 males vs. 3 females), with a median age of 7.5 years [min-max, 0.3-12 years; interquartile range (IQR), 4.4-9.7 years], a median body weight of 24.0 kg (min-max, 6.0-52.3 kg; IQR, 15.6-31.0 kg), and median aortic valve annulus size before surgery of 19.0 mm (min-max, 11.0-25.0 mm; IQR, 17.1-21.5 mm), underwent the neocuspidization technique with pericardium (17 autologous pericardia and 3 bovine patch). With 50% of bicuspid aortic valve and 50% of tricuspid, they were respectively diagnosed as aortic stenosis (AS) (7/20, 35%), aortic regurgitation (AR) (8/20, 40%) and mixed AS and AR (AS & AR) (5/20, 25%). The median postoperative follow-up time was 19 months (min-max, 5-61 months; IQR, 16.3-35 months). The peak pressure gradient across the aortic valve decreased from 81.0±37.0 mmHg in AS group and AS & AR group before surgery to 25.9±15.8 mmHg within 24 hours after surgery (P<0.001) and was mostly around 25 mmHg during follow-up. All patients presented mild or less than mild regurgitation within 24 hours after surgery. There were no hospital mortalities. Three patients needed reintervention during follow-up. There was one late death related to mitral valve stenosis. Conclusions Though the confluent neocuspidization technique with pericardium provided immediate relief of significant AS or regurgitation, the midterm outcome was suboptimal. More research is needed to find the optimal material for AVR.
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Affiliation(s)
- Jiaxi Huang
- Department of Pediatric Cardiothoracic Surgery, Children's Hospital of Fudan University, Shanghai, China
| | - Wenbo Zhang
- Department of Pediatric Cardiothoracic Surgery, Children's Hospital of Fudan University, Shanghai, China
| | - Bing Jia
- Department of Pediatric Cardiothoracic Surgery, Children's Hospital of Fudan University, Shanghai, China
| | - Gang Chen
- Department of Pediatric Cardiothoracic Surgery, Children's Hospital of Fudan University, Shanghai, China
| | - Yaping Mi
- Department of Pediatric Cardiothoracic Surgery, Children's Hospital of Fudan University, Shanghai, China
| | - Qiqi Shi
- Department of Pediatric Cardiothoracic Surgery, Children's Hospital of Fudan University, Shanghai, China
| | - Yaping Shan
- Department of Pediatric Cardiothoracic Surgery, Children's Hospital of Fudan University, Shanghai, China
| | - Huifeng Zhang
- Department of Pediatric Cardiothoracic Surgery, Children's Hospital of Fudan University, Shanghai, China
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3
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Zaitsev VY, Sovetsky AA, Matveyev AL, Matveev LA, Shabanov D, Salamatova VY, Karavaikin PA, Vassilevski YV. Application of compression optical coherence elastography for characterization of human pericardium: A pilot study. JOURNAL OF BIOPHOTONICS 2023; 16:e202200253. [PMID: 36397665 DOI: 10.1002/jbio.202200253] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 10/23/2022] [Accepted: 11/16/2022] [Indexed: 06/16/2023]
Abstract
The recent impressive progress in Compression Optical Coherence Elastography (C-OCE) demonstrated diverse biomedical applications, comprising ophthalmology, oncology, etc. High resolution of C-OCE enables spatially resolved characterization of elasticity of rather thin (thickness < 1 mm) samples, which previously was impossible. Besides Young's modulus, C-OCE enables obtaining of nonlinear stress-strain dependences for various tissues. Here, we report the first application of C-OCE to nondestructively characterize biomechanics of human pericardium, for which data of conventional tensile tests are very limited and controversial. C-OCE revealed pronounced differences among differently prepared pericardium samples. Ample understanding of the influence of chemo-mechanical treatment on pericardium biomechanics is very important because of rapidly growing usage of own patients' pericardium for replacement of aortic valve leaflets in cardio-surgery. The figure demonstrates differences in the tangent Young's modulus after glutaraldehyde-induced cross-linking for two pericardium samples. One sample was over-stretched during the preparation, which caused some damage to the tissue.
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Affiliation(s)
- Vladimir Y Zaitsev
- Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod, Russia
| | - Alexander A Sovetsky
- Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod, Russia
| | - Alexander L Matveyev
- Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod, Russia
| | - Lev A Matveev
- Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod, Russia
| | - Dmitry Shabanov
- Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod, Russia
| | - Victoria Y Salamatova
- Sechenov University, Moscow, Russia
- Sirius University of Science and Technology, Sochi, Russia
| | | | - Yuri V Vassilevski
- Sechenov University, Moscow, Russia
- Sirius University of Science and Technology, Sochi, Russia
- Marchuk Institute of Numerical Mathematics, Russian Academy of Sciences, Moscow, Russia
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4
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Park MH, Zhu Y, Imbrie-Moore AM, Wang H, Marin-Cuartas M, Paulsen MJ, Woo YJ. Heart Valve Biomechanics: The Frontiers of Modeling Modalities and the Expansive Capabilities of Ex Vivo Heart Simulation. Front Cardiovasc Med 2021; 8:673689. [PMID: 34307492 PMCID: PMC8295480 DOI: 10.3389/fcvm.2021.673689] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Accepted: 05/17/2021] [Indexed: 01/05/2023] Open
Abstract
The field of heart valve biomechanics is a rapidly expanding, highly clinically relevant area of research. While most valvular pathologies are rooted in biomechanical changes, the technologies for studying these pathologies and identifying treatments have largely been limited. Nonetheless, significant advancements are underway to better understand the biomechanics of heart valves, pathologies, and interventional therapeutics, and these advancements have largely been driven by crucial in silico, ex vivo, and in vivo modeling technologies. These modalities represent cutting-edge abilities for generating novel insights regarding native, disease, and repair physiologies, and each has unique advantages and limitations for advancing study in this field. In particular, novel ex vivo modeling technologies represent an especially promising class of translatable research that leverages the advantages from both in silico and in vivo modeling to provide deep quantitative and qualitative insights on valvular biomechanics. The frontiers of this work are being discovered by innovative research groups that have used creative, interdisciplinary approaches toward recapitulating in vivo physiology, changing the landscape of clinical understanding and practice for cardiovascular surgery and medicine.
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Affiliation(s)
- Matthew H Park
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, United States.,Department of Mechanical Engineering, Stanford University, Stanford, CA, United States
| | - Yuanjia Zhu
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, United States.,Department of Bioengineering, Stanford University, Stanford, CA, United States
| | - Annabel M Imbrie-Moore
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, United States.,Department of Mechanical Engineering, Stanford University, Stanford, CA, United States
| | - Hanjay Wang
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, United States
| | - Mateo Marin-Cuartas
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, United States.,University Department of Cardiac Surgery, Leipzig Heart Center, Leipzig, Germany
| | - Michael J Paulsen
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, United States
| | - Y Joseph Woo
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, United States.,Department of Bioengineering, Stanford University, Stanford, CA, United States
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5
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Pesce M, Santoro R. Feeling the right force: How to contextualize the cell mechanical behavior in physiologic turnover and pathologic evolution of the cardiovascular system. Pharmacol Ther 2017; 171:75-82. [DOI: 10.1016/j.pharmthera.2016.08.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2016] [Accepted: 07/08/2016] [Indexed: 12/14/2022]
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6
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Zhang F, Kanik J, Mansi T, Voigt I, Sharma P, Ionasec RI, Subrahmanyan L, Lin BA, Sugeng L, Yuh D, Comaniciu D, Duncan J. Towards patient-specific modeling of mitral valve repair: 3D transesophageal echocardiography-derived parameter estimation. Med Image Anal 2017; 35:599-609. [DOI: 10.1016/j.media.2016.09.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Revised: 09/12/2016] [Accepted: 09/19/2016] [Indexed: 11/29/2022]
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7
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Gu Z, Pan Y, Qiao A, Hu X, Dong N, Li X, Liu Y, Shang D. Numerical simulation of closure performance for neo-aortic valve for arterial switch operation. Biomed Eng Online 2016; 15:150. [PMID: 28155693 PMCID: PMC5260105 DOI: 10.1186/s12938-016-0264-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Background Modeling neo-aortic valve for arterial switch surgical planning to simulate the neo-aortic valve closure performance. Methods We created five geometrical models of neo-aortic valve, namely model A, model B, model C, model D and model E with different size of sinotubular junction or sinus. The nodes at the ends of aorta and left ventricle duct fixed all the degrees of freedom. Transvalvular pressure of normal diastolic blood pressure of 54 mmHg was applied on the neo-aortic valve cusps. The neo-aortic valve closure performance was investigated by the parameters, such as stress of neo-aortic root, variation of neo-aortic valve ring as well as aortic valve cusps contact force in the cardiac diastole. Results The maximum stress of the five neo-aortic valves were 96.29, 98.34, 96.28, 98.26, and 90.60 kPa, respectively. Compared among five neo-aortic valve, aortic valve cusps contact forces were changed by 43.33, −10.00% enlarging or narrowing the sinotubular junction by 20% respectively based on the reference model A. The cusps contact forces were changed by 6.67, −23.33% with sinus diameter varying 1.2 times and 0.8 times respectively. Conclusions Comparing with stress of healthy adult subjects, the neo-aortic valve of infant creates lower stress. It is evident that enlarging or narrowing the sinotubular junction within a range of 20% can increase or decrease the maximum stress and aortic valve cusps contact force of neo-aortic valve.
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Affiliation(s)
- Zhaoyong Gu
- College of Life Science and Bio-Engineering, Beijing University of Technology, Pinleyuan, Chaoyang District, Beijing, China
| | - Youlian Pan
- College of Life Science and Bio-Engineering, Beijing University of Technology, Pinleyuan, Chaoyang District, Beijing, China.,College of Mechanical Engineering and Applied Electronics Technology, Beijing University of Technology, Pinleyuan, Chaoyang District, Beijing, China
| | - Aike Qiao
- College of Life Science and Bio-Engineering, Beijing University of Technology, Pinleyuan, Chaoyang District, Beijing, China.
| | - Xingjian Hu
- Department of Cardiovascular Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Jiefang Avenue, Qiaokou District, Wuhan, China
| | - Nianguo Dong
- Department of Cardiovascular Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Jiefang Avenue, Qiaokou District, Wuhan, China.
| | - Xiaofeng Li
- Center of Infant Heart, Beijing Anzhen Hospital, Capital Medical University, AnZhen Road, Chaoyang District, Beijing, China
| | - Yinglong Liu
- Center of Infant Heart, Beijing Anzhen Hospital, Capital Medical University, AnZhen Road, Chaoyang District, Beijing, China
| | - Deguang Shang
- College of Mechanical Engineering and Applied Electronics Technology, Beijing University of Technology, Pinleyuan, Chaoyang District, Beijing, China
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8
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Hammer PE, Roberts EG, Emani SM, Del Nido PJ. Surgical reconstruction of semilunar valves in the growing child: Should we mimic the venous valve? A simulation study. J Thorac Cardiovasc Surg 2016; 153:389-396. [PMID: 27665220 DOI: 10.1016/j.jtcvs.2016.08.019] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Revised: 07/26/2016] [Accepted: 08/02/2016] [Indexed: 10/21/2022]
Abstract
OBJECTIVES Neither heart valve repair methods nor current prostheses can accommodate patient growth. Normal aortic and pulmonary valves have 3 leaflets, and the goal of valve repair and replacement is typically to restore normal 3-leaflet morphology. However, mammalian venous valves have bileaflet morphology and open and close effectively over a wide range of vessel sizes. We propose that they might serve as a model for pediatric heart valve reconstruction and replacement valve design. We explore this concept using computer simulation. METHODS We use a finite element method to simulate the ability of a reconstructed cardiac semilunar valve to close competently in a growing vessel, comparing a 3-leaflet design with a 2-leaflet design that mimics a venous valve. Three venous valve designs were simulated to begin to explore the parameter space. RESULTS Simulations show that for an initial vessel diameter of 12 mm, the venous valve design remains competent as the vessel grows to 20 mm (67%), whereas the normal semilunar design remains competent only to 13 mm (8%). Simulations also suggested that systolic function, estimated as effective orifice area, was not detrimentally affected by the venous valve design, with all 3 venous valve designs exhibiting greater effective orifice area than the semilunar valve design at a given level of vessel growth. CONCLUSIONS Morphologic features of the venous valve design make it well suited for competent closure over a wide range of vessel sizes, suggesting its use as a model for semilunar valve reconstruction in the growing child.
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Affiliation(s)
- Peter E Hammer
- Department of Cardiac Surgery, Boston Children's Hospital, Boston, Mass.
| | - Erin G Roberts
- Department of Cardiac Surgery, Boston Children's Hospital, Boston, Mass; Division of Materials Science and Engineering, Boston University, Boston, Mass
| | - Sitaram M Emani
- Department of Cardiac Surgery, Boston Children's Hospital, Boston, Mass
| | - Pedro J Del Nido
- Department of Cardiac Surgery, Boston Children's Hospital, Boston, Mass
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Hammer PE, Berra I, del Nido PJ. Surgical repair of congenital aortic regurgitation by aortic root reduction: A finite element study. J Biomech 2015; 48:3883-9. [PMID: 26456424 DOI: 10.1016/j.jbiomech.2015.09.030] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 09/15/2015] [Accepted: 09/24/2015] [Indexed: 11/30/2022]
Abstract
During surgical reconstruction of the aortic valve in the child, the use of foreign graft material can limit durability of the repair due to inability of the graft to grow with the child and to accelerated structural degeneration. In this study we use computer simulation and ex vivo experiments to explore a surgical repair method that has the potential to treat a particular form of congenital aortic regurgitation without the introduction of graft material. Specifically, in an aortic valve that is regurgitant due to a congenitally undersized leaflet, we propose resecting a portion of the aortic root belonging to one of the normal leaflets in order to improve valve closure and eliminate regurgitation. We use a structural finite element model of the aortic valve to simulate the closed, pressurized valve following different strategies for surgical reduction of the aortic root (e.g., triangular versus rectangular resection). Results show that aortic root reduction can improve valve closure and eliminate regurgitation, but the effect is highly dependent on the shape and size of the resected region. Only resection strategies that reduce the size of the aortic root at the level of the annulus produce improved valve closure, and only the strategy of resecting a large rectangular portion-extending the full height of the root and reducing root diameter by approximately 12% - is able to eliminate regurgitation and produce an adequate repair. Ex vivo validation experiments in an isolated porcine aorta corroborate simulation results.
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Affiliation(s)
- Peter E Hammer
- Department of Cardiac Surgery, Boston Children's Hospital, Boston, MA, USA.
| | - Ignacio Berra
- Department of Cardiac Surgery, Boston Children's Hospital, Boston, MA, USA; Department of Cardiac Surgery, Hospital Nacional de Pediatría J.P. Garrahan, Buenos Aires, Argentina
| | - Pedro J del Nido
- Department of Cardiac Surgery, Boston Children's Hospital, Boston, MA, USA
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10
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Stern KWD, White MT, Verghese GR, Del Nido PJ, Geva T. Intraoperative Echocardiography for Congenital Aortic Valve Repair: Predictors of Early Reoperation. Ann Thorac Surg 2015; 100:678-85. [PMID: 26138765 DOI: 10.1016/j.athoracsur.2015.05.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Revised: 04/26/2015] [Accepted: 05/01/2015] [Indexed: 10/23/2022]
Abstract
BACKGROUND We sought to identify transesophageal echocardiography (TEE) predictors of early reoperation for recurrent aortic regurgitation (AR) after cardiopulmonary bypass (CPB) in patients undergoing repair for congenital aortic valve disease. METHODS We analyzed post-CPB TEEs in patients with congenital aortic valve disease undergoing repair for predominant AR. Case patients underwent reoperation for recurrent AR within 2 years, whereas control patients were free from reoperation for more than 3 years. RESULTS Case patients (n = 22; median time to reoperation 0.3 years) and control patients (n = 22; median freedom from reoperation ≥4.4 years) were similar for demographic characteristics, aortic dimensions, and preoperative AR grade. Among post-CPB TEE variables, univariate logistic regression analysis identified shorter coaptation height (odds ratio [OR] for 1-mm increase 0.72, 95% confidence interval [CI]: 0.54 to 0.95; p = 0.02), decreased ratio of coaptation height to annulus diameter (OR for a 5% decrease 1.37, 95% CI: 1.06 to 1.77; p = 0.02), and increased percentage difference (%diff) between longest and shortest coaptation lengths in a short-axis view (OR for 10% increase 1.84, 95% CI: 1.15 to 2.92; p = 0.01) as risk factors for early reoperation for recurrent AR. Multivariable analysis identified %diff in short-axis coaptation lengths as the strongest post-CPB TEE predictor (area under receiver operator curve = 0.743). The sensitivity and specificity of a %diff of 50% were 0.45 and 0.91, whereas a %diff of 30% had a sensitivity of 0.75 and specificity of 0.67. CONCLUSIONS Coaptation asymmetry, measured as increased %diff in short-axis coaptation lengths on post-CPB TEE, is associated with early reoperation for recurrent AR after congenital valve repair.
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Affiliation(s)
- Kenan W D Stern
- Department of Cardiology, Boston Children's Hospital, Boston, Massachusetts; Department of Pediatrics, Harvard Medical School, Boston, Massachusetts.
| | - Matthew T White
- Clinical Research Center, Boston Children's Hospital, Boston, Massachusetts; Department of Psychiatry, Harvard Medical School, Boston, Massachusetts
| | - George R Verghese
- Department of Cardiology, Boston Children's Hospital, Boston, Massachusetts; Department of Pediatrics, Harvard Medical School, Boston, Massachusetts
| | - Pedro J Del Nido
- Department of Cardiac Surgery, Boston Children's Hospital, Boston, Massachusetts; Department of Surgery, Harvard Medical School, Boston, Massachusetts
| | - Tal Geva
- Department of Cardiology, Boston Children's Hospital, Boston, Massachusetts; Department of Pediatrics, Harvard Medical School, Boston, Massachusetts
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11
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Pavan PG, Pachera P, Tiengo C, Natali AN. Biomechanical behavior of pericardial human tissue: a constitutive formulation. Proc Inst Mech Eng H 2014; 228:926-34. [PMID: 25224743 DOI: 10.1177/0954411914551853] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
This work aims to present a constitutive model suitable to interpret the biomechanical response of human pericardial tissues. The model is consistent with the need of describing large strains, anisotropy, almost incompressibility, and time-dependent effects. Attention is given to human pericardial tissue because of the increased interest in its application as a substitute in reconstructive surgery. Specific, even limited, experimental investigation has been performed on human samples taken from surgical grafts in order to verify the capability of the constitutive model in supplying a correct description of tissue mechanical response. Experimental data include uni-axial tensile tests and stress relaxation tests up to 300 s, developed along different directions of the tissue. The grafts tested show different mechanical characteristics for what concern the level of anisotropy of the tissue. The constitutive model proposed shows to adapt to the different configurations of the human pericardium grafts, as emerged by experimental data considered, and it is capable to describe the variability of the mechanical characteristics.
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Affiliation(s)
- Piero G Pavan
- Department of Industrial Engineering, University of Padova, Padova, Italy Centre of Mechanics of Biological Materials, University of Padova, Padova, Italy
| | - Paola Pachera
- Department of Industrial Engineering, University of Padova, Padova, Italy Centre of Mechanics of Biological Materials, University of Padova, Padova, Italy
| | - Cesare Tiengo
- Department of Industrial Engineering, University of Padova, Padova, Italy Department of Molecular Medicine, University of Padova, Padova, Italy
| | - Arturo N Natali
- Department of Industrial Engineering, University of Padova, Padova, Italy Centre of Mechanics of Biological Materials, University of Padova, Padova, Italy
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12
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Ovcharenko EA, Klyshnikov KU, Vlad AR, Sizova IN, Kokov AN, Nushtaev DV, Yuzhalin AE, Zhuravleva IU. Computer-aided design of the human aortic root. Comput Biol Med 2014; 54:109-15. [PMID: 25238567 DOI: 10.1016/j.compbiomed.2014.08.023] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Revised: 08/20/2014] [Accepted: 08/22/2014] [Indexed: 11/28/2022]
Abstract
The development of computer-based 3D models of the aortic root is one of the most important problems in constructing the prostheses for transcatheter aortic valve implantation. In the current study, we analyzed data from 117 patients with and without aortic valve disease and computed tomography data from 20 patients without aortic valvular diseases in order to estimate the average values of the diameter of the aortic annulus and other aortic root parameters. Based on these data, we developed a 3D model of human aortic root with unique geometry. Furthermore, in this study we show that by applying different material properties to the aortic annulus zone in our model, we can significantly improve the quality of the results of finite element analysis. To summarize, here we present four 3D models of human aortic root with unique geometry based on computational analysis of ECHO and CT data. We suggest that our models can be utilized for the development of better prostheses for transcatheter aortic valve implantation.
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Affiliation(s)
- E A Ovcharenko
- Research Institute for Complex Issues of Cardiovascular Diseases under the Siberian Branch of the Russian Academy of Medical Sciences, Kemerovo, Russian Federation
| | - K U Klyshnikov
- Research Institute for Complex Issues of Cardiovascular Diseases under the Siberian Branch of the Russian Academy of Medical Sciences, Kemerovo, Russian Federation.
| | - A R Vlad
- Research Institute for Complex Issues of Cardiovascular Diseases under the Siberian Branch of the Russian Academy of Medical Sciences, Kemerovo, Russian Federation
| | - I N Sizova
- Research Institute for Complex Issues of Cardiovascular Diseases under the Siberian Branch of the Russian Academy of Medical Sciences, Kemerovo, Russian Federation
| | - A N Kokov
- Research Institute for Complex Issues of Cardiovascular Diseases under the Siberian Branch of the Russian Academy of Medical Sciences, Kemerovo, Russian Federation
| | - D V Nushtaev
- "TESIS" Limited Liability Company, Moscow, Russian Federation
| | - A E Yuzhalin
- Department of Oncology, Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, University of Oxford, Oxford, United Kingdom
| | - I U Zhuravleva
- Research Institute for Complex Issues of Cardiovascular Diseases under the Siberian Branch of the Russian Academy of Medical Sciences, Kemerovo, Russian Federation
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Straightening of curved pattern of collagen fibers under load controls aortic valve shape. J Biomech 2013; 47:341-6. [PMID: 24315286 DOI: 10.1016/j.jbiomech.2013.11.032] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Revised: 11/01/2013] [Accepted: 11/21/2013] [Indexed: 02/07/2023]
Abstract
The network of collagen fibers in the aortic valve leaflet is believed to play an important role in the strength and durability of the valve. However, in addition to its stress-bearing role, such a fiber network has the potential to produce functionally important shape changes in the closed valve under pressure load. We measured the average pattern of the collagen network in porcine aortic valve leaflets after staining for collagen. We then used finite element simulation to explore how this collagen pattern influences the shape of the closed valve. We observed a curved or bent pattern, with collagen fibers angled downward from the commissures toward the center of the leaflet to form a pattern that is concave toward the leaflet free edge. Simulations showed that these curved fiber trajectories straighten under pressure load, leading to functionally important changes in closed valve shape. Relative to a pattern of straight collagen fibers running parallel to the leaflet free edge, the concave pattern of curved fibers produces a closed valve with a 40% increase in central leaflet coaptation height and with decreased leaflet billow, resulting in a more physiological closed valve shape. Furthermore, simulations show that these changes in loaded leaflet shape reflect changes in leaflet curvature due to modulation of in-plane membrane stress resulting from straightening of the curved fibers. This effect appears to play an important role in normal valve function and may have important implications for the design of prosthetic and tissue engineered replacement valves.
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Hammer PE, del Nido PJ. Guidelines for sizing pericardium for aortic valve leaflet grafts. Ann Thorac Surg 2013; 96:e25-7. [PMID: 23816114 DOI: 10.1016/j.athoracsur.2013.04.085] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2012] [Revised: 04/02/2013] [Accepted: 04/08/2013] [Indexed: 11/26/2022]
Abstract
Surgical repair of the aortic valve with the use of leaflet grafts made from pericardium has been shown to be a viable option, particularly in children, in whom valve replacement has strong disadvantages. We present guidelines for sizing treated autologous pericardium to fabricate a leaflet graft for single-leaflet replacement. Both our clinical experience and experimental evidence indicate that effective repairs are best achieved by use of a semicircular graft with a diameter 10% to 15% greater than the sinotubular junction diameter in diastole. We also provide a simple formula to allow adjustment of these guidelines to account for variations in valve geometry and tissue properties.
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Affiliation(s)
- Peter E Hammer
- Department of Cardiac Surgery, Boston Children's Hospital, Boston, Massachusetts 02115, USA.
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Votta E, Le TB, Stevanella M, Fusini L, Caiani EG, Redaelli A, Sotiropoulos F. Toward patient-specific simulations of cardiac valves: state-of-the-art and future directions. J Biomech 2012; 46:217-28. [PMID: 23174421 DOI: 10.1016/j.jbiomech.2012.10.026] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2012] [Accepted: 10/23/2012] [Indexed: 10/27/2022]
Abstract
Recent computational methods enabling patient-specific simulations of native and prosthetic heart valves are reviewed. Emphasis is placed on two critical components of such methods: (1) anatomically realistic finite element models for simulating the structural dynamics of heart valves; and (2) fluid structure interaction methods for simulating the performance of heart valves in a patient-specific beating left ventricle. It is shown that the significant progress achieved in both fronts paves the way toward clinically relevant computational models that can simulate the performance of a range of heart valves, native and prosthetic, in a patient-specific left heart environment. The significant algorithmic and model validation challenges that need to be tackled in the future to realize this goal are also discussed.
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Affiliation(s)
- Emiliano Votta
- Bioengineering Department, Politecnico di Milano, Milano, Italy
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