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Laudenschlager S, Schofield S, Drysdale N, Stone M, Romanowicz J, Frank B, DiMaria M, Kheyfets VO, Hedjazi-Moghari M. Estimation of pulmonary vascular resistance for Glenn physiology. PLoS One 2024; 19:e0307890. [PMID: 39058711 PMCID: PMC11280147 DOI: 10.1371/journal.pone.0307890] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2024] [Accepted: 07/12/2024] [Indexed: 07/28/2024] Open
Abstract
Children with single ventricle heart disease typically require a series of three operations, (1) Norwood, (2) Glenn, and (3) Fontan, which ultimately results in complete separation of the pulmonary and systemic circuits to improve pulmonary/systemic circulation. In the last stage, the Fontan operation, the inferior vena cava (IVC) is connected to the pulmonary arteries (PAs), allowing the remainder of deoxygenated blood to passively flow to the pulmonary circuit. It is hypothesized that optimizing the Fontan anatomy would lead to decreased power loss and more balanced hepatic flow distribution. One approach to optimizing the geometry is to create a patient-specific digital twin to simulate various configurations of the Fontan conduit, which requires a computational model of the proximal PA anatomy and resistance, as well as the distal Pulmonary Vascular Resistance (PVR), at the Glenn stage. To that end, an optimization pipeline was developed using 3D computational fluid dynamics (CFD) and 0D lumped parameter (LP) simulations to iteratively refine the PVR of each lung by minimizing the simulated flow and pressure error relative to patients' cardiac magnetic resonance (CMR) and catheterization (CATH) data. While the PVR can also be estimated directly by computing the ratio of pressure gradients and flow from CATH and CMR data, the computational approach can separately identify the different components of PVR along the Glenn pathway, allowing for a more detailed depiction of the Glenn vasculature. Results indicate good correlation between the optimized PVR of the CFD and LP models (n = 16), with an intraclass correlation coefficient (ICC) of 0.998 (p = 0.976) and 0.991 (p = 0.943) for the left and right lung, respectively. Furthermore, compared to CMR flow and CATH pressure data, the optimized PVR estimates result in mean outlet flow and pressure errors of less than 5%. The optimized PVR estimates also agree well with the computed PVR estimates from CATH pressure and CMR flow for both lungs, yielding a mean difference of less than 4%.
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Affiliation(s)
- Sebastian Laudenschlager
- Department of Radiology, School of Medicine, University of Colorado, Aurora, CO, United States of America
| | - Samuel Schofield
- Department of Cardiology, University of Colorado and Children’s Hospital Colorado, Aurora, CO, United States of America
| | - Nicolas Drysdale
- Department of Surgery, School of Medicine, University of Colorado, Aurora, CO, United States of America
| | - Matthew Stone
- Department of Surgery, University of Colorado and Children’s Hospital Colorado, Aurora, CO, United States of America
| | - Jennifer Romanowicz
- Department of Cardiology, University of Colorado and Children’s Hospital Colorado, Aurora, CO, United States of America
| | - Benjamin Frank
- Department of Cardiology, University of Colorado and Children’s Hospital Colorado, Aurora, CO, United States of America
| | - Michael DiMaria
- Department of Cardiology, University of Colorado and Children’s Hospital Colorado, Aurora, CO, United States of America
| | - Vitaly O. Kheyfets
- Department of Critical Care, University of Colorado and Children’s Hospital Colorado, Aurora, CO, United States of America
| | - Mehdi Hedjazi-Moghari
- Department of Radiology, University of Colorado and Children’s Hospital Colorado, Aurora, CO, United States of America
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2
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Nair PJ, Pfaller MR, Dual SA, McElhinney DB, Ennis DB, Marsden AL. Non-invasive Estimation of Pressure Drop Across Aortic Coarctations: Validation of 0D and 3D Computational Models with In Vivo Measurements. Ann Biomed Eng 2024; 52:1335-1346. [PMID: 38341399 DOI: 10.1007/s10439-024-03457-5] [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: 09/04/2023] [Accepted: 01/20/2024] [Indexed: 02/12/2024]
Abstract
Blood pressure gradient ( Δ P ) across an aortic coarctation (CoA) is an important measurement to diagnose CoA severity and gauge treatment efficacy. Invasive cardiac catheterization is currently the gold-standard method for measuring blood pressure. The objective of this study was to evaluate the accuracy of Δ P estimates derived non-invasively using patient-specific 0D and 3D deformable wall simulations. Medical imaging and routine clinical measurements were used to create patient-specific models of patients with CoA (N = 17). 0D simulations were performed first and used to tune boundary conditions and initialize 3D simulations. Δ P across the CoA estimated using both 0D and 3D simulations were compared to invasive catheter-based pressure measurements for validation. The 0D simulations were extremely efficient ( ∼ 15 s computation time) compared to 3D simulations ( ∼ 30 h computation time on a cluster). However, the 0D Δ P estimates, unsurprisingly, had larger mean errors when compared to catheterization than 3D estimates (12.1 ± 9.9 mmHg vs 5.3 ± 5.4 mmHg). In particular, the 0D model performance degraded in cases where the CoA was adjacent to a bifurcation. The 0D model classified patients with severe CoA requiring intervention (defined as Δ P ≥ 20 mmHg) with 76% accuracy and 3D simulations improved this to 88%. Overall, a combined approach, using 0D models to efficiently tune and launch 3D models, offers the best combination of speed and accuracy for non-invasive classification of CoA severity.
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Affiliation(s)
- Priya J Nair
- Department of Bioengineering, Stanford University, Stanford, CA, USA
- Stanford Cardiovascular Institute, Stanford University, Stanford, CA, USA
| | - Martin R Pfaller
- Stanford Cardiovascular Institute, Stanford University, Stanford, CA, USA
- Department of Pediatrics - Cardiology, Stanford University, Stanford, CA, USA
- Maternal and Child Health Research Institute, Stanford University, Stanford, CA, USA
- Institute for Computational and Mathematical Engineering, Stanford University, Stanford, CA, USA
| | - Seraina A Dual
- Department of Biomedical Signaling and Health Systems, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Doff B McElhinney
- Stanford Cardiovascular Institute, Stanford University, Stanford, CA, USA
- Department of Pediatrics - Cardiology, Stanford University, Stanford, CA, USA
- Maternal and Child Health Research Institute, Stanford University, Stanford, CA, USA
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, USA
| | - Daniel B Ennis
- Stanford Cardiovascular Institute, Stanford University, Stanford, CA, USA
- Maternal and Child Health Research Institute, Stanford University, Stanford, CA, USA
- Department of Radiology, Stanford University, Stanford, CA, USA
- Division of Radiology, VA Palo Alto Healthcare System, Palo Alto, CA, USA
| | - Alison L Marsden
- Department of Bioengineering, Stanford University, Stanford, CA, USA.
- Stanford Cardiovascular Institute, Stanford University, Stanford, CA, USA.
- Department of Pediatrics - Cardiology, Stanford University, Stanford, CA, USA.
- Maternal and Child Health Research Institute, Stanford University, Stanford, CA, USA.
- Institute for Computational and Mathematical Engineering, Stanford University, Stanford, CA, USA.
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3
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Szafron JM, Heng EE, Boyd J, Humphrey JD, Marsden AL. Hemodynamics and Wall Mechanics of Vascular Graft Failure. Arterioscler Thromb Vasc Biol 2024; 44:1065-1085. [PMID: 38572650 PMCID: PMC11043008 DOI: 10.1161/atvbaha.123.318239] [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: 09/04/2023] [Accepted: 03/12/2024] [Indexed: 04/05/2024]
Abstract
Blood vessels are subjected to complex biomechanical loads, primarily from pressure-driven blood flow. Abnormal loading associated with vascular grafts, arising from altered hemodynamics or wall mechanics, can cause acute and progressive vascular failure and end-organ dysfunction. Perturbations to mechanobiological stimuli experienced by vascular cells contribute to remodeling of the vascular wall via activation of mechanosensitive signaling pathways and subsequent changes in gene expression and associated turnover of cells and extracellular matrix. In this review, we outline experimental and computational tools used to quantify metrics of biomechanical loading in vascular grafts and highlight those that show potential in predicting graft failure for diverse disease contexts. We include metrics derived from both fluid and solid mechanics that drive feedback loops between mechanobiological processes and changes in the biomechanical state that govern the natural history of vascular grafts. As illustrative examples, we consider application-specific coronary artery bypass grafts, peripheral vascular grafts, and tissue-engineered vascular grafts for congenital heart surgery as each of these involves unique circulatory environments, loading magnitudes, and graft materials.
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Affiliation(s)
- Jason M Szafron
- Departments of Pediatrics (J.M.S., A.L.M.), Stanford University, CA
| | - Elbert E Heng
- Cardiothoracic Surgery (E.E.H., J.B.), Stanford University, CA
| | - Jack Boyd
- Cardiothoracic Surgery (E.E.H., J.B.), Stanford University, CA
| | - Jay D Humphrey
- Department of Biomedical Engineering, Yale University, New Haven, CT (J.D.H.)
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4
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Rasooli R, Holmstrom H, Giljarhus KET, Jolma IW, Vinningland JL, de Lange C, Brun H, Hiorth A. In vitro hemodynamic performance of a blood pump for self-powered venous assist in univentricular hearts. Sci Rep 2024; 14:6941. [PMID: 38521832 PMCID: PMC10960831 DOI: 10.1038/s41598-024-57269-7] [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: 09/05/2023] [Accepted: 03/15/2024] [Indexed: 03/25/2024] Open
Abstract
Univentricular heart anomalies represent a group of severe congenital heart defects necessitating early surgical intervention in infancy. The Fontan procedure, the final stage of single-ventricle palliation, establishes a serial connection between systemic and pulmonary circulation by channeling venous return to the lungs. The absence of the subpulmonary ventricle in this peculiar circulation progressively eventuates in failure, primarily due to chronic elevation in inferior vena cava (IVC) pressure. This study experimentally validates the effectiveness of an intracorporeally-powered venous ejector pump (VEP) in reducing IVC pressure in Fontan patients. The VEP exploits a fraction of aortic flow to create a jet-venturi effect for the IVC, negating the external power requirement and driveline infections. An invitro Fontan mock-up circulation loop is developed and the impact of VEP design parameters and physiological conditions is assessed using both idealized and patient-specific total cavopulmonary connection (TCPC) phantoms. The VEP performance in reducing IVC pressure exhibited an inverse relationship with the cardiac output and extra-cardiac conduit (ECC) size and a proportional relationship with the transpulmonary pressure gradient (TPG) and mean arterial pressure (MAP). The ideal VEP with fail-safe features provided an IVC pressure drop of 1.82 ± 0.49, 2.45 ± 0.54, and 3.12 ± 0.43 mm Hg for TPG values of 6, 8, and 10 mm Hg, respectively, averaged over all ECC sizes and cardiac outputs. Furthermore, the arterial oxygen saturation was consistently maintained above 85% during full-assist mode. These results emphasize the potential utility of the VEP to mitigate elevated venous pressure in Fontan patients.
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Affiliation(s)
- Reza Rasooli
- Department of Energy Resources, Faculty of Science and Technology, University of Stavanger, 4036, Stavanger, Norway.
| | - Henrik Holmstrom
- Department of Pediatric Cardiology, Division of Pediatric and Adolescent Medicine, Oslo University Hospital, Oslo, Norway
- Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Knut Erik Teigen Giljarhus
- Department of Mechanical and Structural Engineering and Materials Science, University of Stavanger, 4036, Stavanger, Norway
| | - Ingunn Westvik Jolma
- Department of Chemistry, Bioscience and Environmental Engineering, University of Stavanger, 4036, Stavanger, Norway
| | | | - Charlotte de Lange
- Department of Pediatric Radiology, Sahlgrenska University Hospital, Gothenburg, Sweden
- Institute of Clinical Science, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Henrik Brun
- Department of Pediatric Cardiology, Division of Pediatric and Adolescent Medicine, Oslo University Hospital, Oslo, Norway
- Section for Medical Cybernetics and Image Processing, The Intervention Centre, Oslo University Hospital Rikshospitalet, Oslo, Norway
| | - Aksel Hiorth
- Department of Energy Resources, Faculty of Science and Technology, University of Stavanger, 4036, Stavanger, Norway
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5
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Brown AL, Salvador M, Shi L, Pfaller MR, Hu Z, Harold KE, Hsiai T, Vedula V, Marsden AL. A Modular Framework for Implicit 3D-0D Coupling in Cardiac Mechanics. COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING 2024; 421:116764. [PMID: 38523716 PMCID: PMC10956732 DOI: 10.1016/j.cma.2024.116764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/26/2024]
Abstract
In numerical simulations of cardiac mechanics, coupling the heart to a model of the circulatory system is essential for capturing physiological cardiac behavior. A popular and efficient technique is to use an electrical circuit analogy, known as a lumped parameter network or zero-dimensional (0D) fluid model, to represent blood flow throughout the cardiovascular system. Due to the strong physical interaction between the heart and the blood circulation, developing accurate and efficient numerical coupling methods remains an active area of research. In this work, we present a modular framework for implicitly coupling three-dimensional (3D) finite element simulations of cardiac mechanics to 0D models of blood circulation. The framework is modular in that the circulation model can be modified independently of the 3D finite element solver, and vice versa. The numerical scheme builds upon a previous work that combines 3D blood flow models with 0D circulation models (3D fluid - 0D fluid). Here, we extend it to couple 3D cardiac tissue mechanics models with 0D circulation models (3D structure - 0D fluid), showing that both mathematical problems can be solved within a unified coupling scheme. The effectiveness, temporal convergence, and computational cost of the algorithm are assessed through multiple examples relevant to the cardiovascular modeling community. Importantly, in an idealized left ventricle example, we show that the coupled model yields physiological pressure-volume loops and naturally recapitulates the isovolumic contraction and relaxation phases of the cardiac cycle without any additional numerical techniques. Furthermore, we provide a new derivation of the scheme inspired by the Approximate Newton Method of Chan (1985), explaining how the proposed numerical scheme combines the stability of monolithic approaches with the modularity and flexibility of partitioned approaches.
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Affiliation(s)
- Aaron L. Brown
- Department of Mechanical Engineering, Stanford University, Stanford, CA, USA
- Stanford Cardiovascular Institute, Stanford, CA, USA
| | - Matteo Salvador
- Institute for Computational and Mathematical Engineering, Stanford University, Stanford, CA, USA
- Stanford Cardiovascular Institute, Stanford, CA, USA
- Department of Pediatrics (Cardiology), Stanford University, Stanford, CA, USA
| | - Lei Shi
- Department of Mechanical Engineering, Columbia University, New York, NY, USA
- Department of Mechanical Engineering, Kennesaw State University, Marietta, GA, USA
| | - Martin R. Pfaller
- Institute for Computational and Mathematical Engineering, Stanford University, Stanford, CA, USA
- Stanford Cardiovascular Institute, Stanford, CA, USA
- Department of Pediatrics (Cardiology), Stanford University, Stanford, CA, USA
| | - Zinan Hu
- Department of Mechanical Engineering, Stanford University, Stanford, CA, USA
| | - Kaitlin E. Harold
- Department of Computer Science, Stanford University, Stanford, CA, USA
| | - Tzung Hsiai
- Department of Bioengineering, University of California Los Angeles, Los Angeles, CA, USA
| | - Vijay Vedula
- Department of Mechanical Engineering, Columbia University, New York, NY, USA
| | - Alison L. Marsden
- Department of Mechanical Engineering, Stanford University, Stanford, CA, USA
- Institute for Computational and Mathematical Engineering, Stanford University, Stanford, CA, USA
- Stanford Cardiovascular Institute, Stanford, CA, USA
- Department of Pediatrics (Cardiology), Stanford University, Stanford, CA, USA
- Department of Bioengineering, Stanford University, Stanford, CA, USA
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6
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Pegolotti L, Pfaller MR, Rubio NL, Ding K, Brugarolas Brufau R, Darve E, Marsden AL. Learning reduced-order models for cardiovascular simulations with graph neural networks. Comput Biol Med 2024; 168:107676. [PMID: 38039892 PMCID: PMC10886437 DOI: 10.1016/j.compbiomed.2023.107676] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 10/23/2023] [Accepted: 11/06/2023] [Indexed: 12/03/2023]
Abstract
Reduced-order models based on physics are a popular choice in cardiovascular modeling due to their efficiency, but they may experience loss in accuracy when working with anatomies that contain numerous junctions or pathological conditions. We develop one-dimensional reduced-order models that simulate blood flow dynamics using a graph neural network trained on three-dimensional hemodynamic simulation data. Given the initial condition of the system, the network iteratively predicts the pressure and flow rate at the vessel centerline nodes. Our numerical results demonstrate the accuracy and generalizability of our method in physiological geometries comprising a variety of anatomies and boundary conditions. Our findings demonstrate that our approach can achieve errors below 3% for pressure and flow rate, provided there is adequate training data. As a result, our method exhibits superior performance compared to physics-based one-dimensional models while maintaining high efficiency at inference time.
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Affiliation(s)
- Luca Pegolotti
- Department of Pediatrics, Stanford University, United States of America; Institute for Computational and Mathematical Engineering, Stanford University, United States of America.
| | - Martin R Pfaller
- Department of Pediatrics, Stanford University, United States of America; Institute for Computational and Mathematical Engineering, Stanford University, United States of America
| | - Natalia L Rubio
- Department of Mechanical Engineering, Stanford University, United States of America
| | - Ke Ding
- Intel Corporation, United States of America
| | | | - Eric Darve
- Institute for Computational and Mathematical Engineering, Stanford University, United States of America; Department of Mechanical Engineering, Stanford University, United States of America
| | - Alison L Marsden
- Department of Pediatrics, Stanford University, United States of America; Institute for Computational and Mathematical Engineering, Stanford University, United States of America; Department of Mechanical Engineering, Stanford University, United States of America; Department of Bioengineering, Stanford University, United States of America
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7
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Grande Gutiérrez N, Mukherjee D, Bark D. Decoding thrombosis through code: a review of computational models. J Thromb Haemost 2024; 22:35-47. [PMID: 37657562 PMCID: PMC11064820 DOI: 10.1016/j.jtha.2023.08.021] [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: 10/07/2022] [Revised: 08/15/2023] [Accepted: 08/22/2023] [Indexed: 09/03/2023]
Abstract
From the molecular level up to a blood vessel, thrombosis and hemostasis involves many interconnected biochemical and biophysical processes over a wide range of length and time scales. Computational modeling has gained eminence in offering insights into these processes beyond what can be obtained from in vitro or in vivo experiments, or clinical measurements. The multiscale and multiphysics nature of thrombosis has inspired a wide range of modeling approaches that aim to address how a thrombus forms and dismantles. Here, we review recent advances in computational modeling with a focus on platelet-based thrombosis. We attempt to summarize the diverse range of modeling efforts straddling the wide-spectrum of physical phenomena, length scales, and time scales; highlighting key advancements and insights from existing studies. Potential information gleaned from models is discussed, ranging from identification of thrombus-prone regions in patient-specific vasculature to modeling thrombus deformation and embolization in response to fluid forces. Furthermore, we highlight several limitations of current models, future directions in the field, and opportunities for clinical translation, to illustrate the state-of-the-art. There are a plethora of opportunity areas for which models can be expanded, ranging from topics of thromboinflammation to platelet production and clearance. Through successes demonstrated in existing studies described here, as well as continued advancements in computational methodologies and computer processing speeds and memory, in silico investigations in thrombosis are poised to bring about significant knowledge growth in the years to come.
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Affiliation(s)
- Noelia Grande Gutiérrez
- Carnegie Mellon University, Department of Mechanical Engineering Pittsburgh, PA, USA. https://twitter.com/ngrandeg
| | - Debanjan Mukherjee
- University of Colorado Boulder, Paul M. Rady Department of Mechanical Engineering Boulder, CO, USA. https://twitter.com/debanjanmukh
| | - David Bark
- Washington University in St Louis, Department of Pediatrics, Division of Hematology and Oncology St Louis, MO, USA; Washington University in St Louis, Department of Biomedical Engineering St Louis, MO, USA.
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8
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Nair PJ, Pfaller MR, Dual SA, McElhinney DB, Ennis DB, Marsden AL. Non-invasive estimation of pressure drop across aortic coarctations: validation of 0D and 3D computational models with in vivo measurements. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.09.05.23295066. [PMID: 37732242 PMCID: PMC10508787 DOI: 10.1101/2023.09.05.23295066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/22/2023]
Abstract
Purpose Blood pressure gradient (Δ P ) across an aortic coarctation (CoA) is an important measurement to diagnose CoA severity and gauge treatment efficacy. Invasive cardiac catheterization is currently the gold-standard method for measuring blood pressure. The objective of this study was to evaluate the accuracy of Δ P estimates derived non-invasively using patient-specific 0 D and 3 D deformable wall simulations. Methods Medical imaging and routine clinical measurements were used to create patient-specific models of patients with CoA (N = 17 ). 0 D simulations were performed first and used to tune boundary conditions and initialize 3 D simulations. Δ P across the CoA estimated using both 0 D and 3 D simulations were compared to invasive catheter-based pressure measurements for validation. Results The 0 D simulations were extremely efficient (~15 secs computation time) compared to 3 D simulations (~30 hrs computation time on a cluster). However, the 0 D Δ P estimates, unsurprisingly, had larger mean errors when compared to catheterization than 3 D estimates (12.1 ± 9.9 mmHg vs 5.3 ± 5.4 mmHg). In particular, the 0 D model performance degraded in cases where the CoA was adjacent to a bifurcation. The 0 D model classified patients with severe CoA requiring intervention (defined as Δ P ≥ 20 mmHg) with 76% accuracy and 3 D simulations improved this to 88%. Conclusion Overall, a combined approach, using 0 D models to efficiently tune and launch 3 D models, offers the best combination of speed and accuracy for non-invasive classification of CoA severity.
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Affiliation(s)
- Priya J. Nair
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Martin R. Pfaller
- Stanford Cardiovascular Institute, Stanford University, Stanford, CA, USA
- Department of Pediatrics - Cardiology, Stanford University, Stanford, CA, USA
- Maternal and Child Health Research Institute, Stanford University, Stanford, CA, USA
- Institute for Computational and Mathematical Engineering, Stanford University, Stanford, CA, USA
| | - Seraina A. Dual
- Department of Biomedical Signaling and Health Systems, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Doff B. McElhinney
- Stanford Cardiovascular Institute, Stanford University, Stanford, CA, USA
- Department of Pediatrics - Cardiology, Stanford University, Stanford, CA, USA
- Maternal and Child Health Research Institute, Stanford University, Stanford, CA, USA
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, USA
| | - Daniel B. Ennis
- Stanford Cardiovascular Institute, Stanford University, Stanford, CA, USA
- Maternal and Child Health Research Institute, Stanford University, Stanford, CA, USA
- Department of Radiology, Stanford University, Stanford, CA, USA
- Division of Radiology, VA Palo Alto Healthcare System, Palo Alto, CA, USA
| | - Alison L. Marsden
- Department of Bioengineering, Stanford University, Stanford, CA, USA
- Stanford Cardiovascular Institute, Stanford University, Stanford, CA, USA
- Department of Pediatrics - Cardiology, Stanford University, Stanford, CA, USA
- Maternal and Child Health Research Institute, Stanford University, Stanford, CA, USA
- Institute for Computational and Mathematical Engineering, Stanford University, Stanford, CA, USA
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9
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Tobin N, Li M, Hiller G, Azimi A, Manning KB. Clot embolization studies and computational framework for embolization in a canonical tube model. Sci Rep 2023; 13:14682. [PMID: 37673915 PMCID: PMC10482921 DOI: 10.1038/s41598-023-41825-8] [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: 05/16/2023] [Accepted: 08/31/2023] [Indexed: 09/08/2023] Open
Abstract
Despite recent advances in the development of computational methods of modeling thrombosis, relatively little effort has been made in developing methods of modeling blood clot embolization. Such a model would provide substantially greater understanding of the mechanics of embolization, as in-vitro and in-vivo characterization of embolization is difficult. Here, a method of computationally simulating embolization is developed. Experiments are performed of blood clots formed in a polycarbonate tube, where phosphate-buffered saline is run through the tube at increasing flow rates until the clot embolizes. The experiments revealed embolization can be initiated by leading edge and trailing edge detachment or by non-uniform detachment. Stress-relaxation experiments are also performed to establish values of constitutive parameters for subsequent simulations. The embolization in the tube is reproduced in silico using a multiphase volume-of-fluid approach, where the clot is modeled as viscoelastic. By varying the constitutive parameters at the wall, embolization can be reproduced in-silico at varying flow rates, and a range of constitutive parameters fitting the experiments is reported. Here, the leading edge embolization is simulated at flow rates consistent with the experiments demonstrating excellent agreement in this specific behavior.
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Affiliation(s)
- Nicolas Tobin
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Menghan Li
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Gretchen Hiller
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Arash Azimi
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Keefe B Manning
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA.
- Department of Surgery, Penn State College of Medicine, Hershey, PA, 17033, USA.
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10
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Yang W, Conover TA, Figliola RS, Giridharan GA, Marsden AL, Rodefeld MD. Passive performance evaluation and validation of a viscous impeller pump for subpulmonary fontan circulatory support. Sci Rep 2023; 13:12668. [PMID: 37542111 PMCID: PMC10403595 DOI: 10.1038/s41598-023-38559-y] [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: 02/14/2023] [Accepted: 07/11/2023] [Indexed: 08/06/2023] Open
Abstract
Patients with single ventricle defects undergoing the Fontan procedure eventually face Fontan failure. Long-term cavopulmonary assist devices using rotary pump technologies are currently being developed as a subpulmonary power source to prevent and treat Fontan failure. Low hydraulic resistance is a critical safety requirement in the event of pump failure (0 RPM) as a modest 2 mmHg cavopulmonary pressure drop can compromise patient hemodynamics. The goal of this study is therefore to assess the passive performance of a viscous impeller pump (VIP) we are developing for Fontan patients, and validate flow simulations against in-vitro data. Two different blade heights (1.09 mm vs 1.62 mm) and a blank housing model were tested using a mock circulatory loop (MCL) with cardiac output ranging from 3 to 11 L/min. Three-dimensional flow simulations were performed and compared against MCL data. In-silico and MCL results demonstrated a pressure drop of < 2 mmHg at a cardiac output of 7 L/min for both blade heights. There was good agreement between simulation and MCL results for pressure loss (mean difference - 0.23 mmHg 95% CI [0.24-0.71]). Compared to the blank housing model, low wall shear stress area and oscillatory shear index on the pump surface were low, and mean washout times were within 2 s. This study demonstrated the low resistance characteristic of current VIP designs in the failed condition that results in clinically acceptable minimal pressure loss without increased washout time as compared to a blank housing model under normal cardiac output in Fontan patients.
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Affiliation(s)
- Weiguang Yang
- Department of Pediatrics (Cardiology), Stanford University, Stanford, CA, USA.
| | - Timothy A Conover
- Departments of Mechanical Engineering, Clemson University, Clemson, SC, USA
| | - Richard S Figliola
- Departments of Mechanical Engineering, Clemson University, Clemson, SC, USA
| | | | - Alison L Marsden
- Department of Pediatrics (Cardiology), Stanford University, Stanford, CA, USA
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Mark D Rodefeld
- Section of Cardiothoracic Surgery, Department of Surgery, Indiana University School of Medicine, Indianapolis, IN, USA
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11
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Rasooli R, Giljarhus KET, Hiorth A, Jolma IW, Vinningland JL, de Lange C, Brun H, Holmstrom H. In Silico Evaluation of a Self-powered Venous Ejector Pump for Fontan Patients. Cardiovasc Eng Technol 2023; 14:428-446. [PMID: 36877450 PMCID: PMC10412470 DOI: 10.1007/s13239-023-00663-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Accepted: 02/06/2023] [Indexed: 03/07/2023]
Abstract
PURPOSE The Fontan circulation carries a dismal prognosis in the long term due to its peculiar physiology and lack of a subpulmonic ventricle. Although it is multifactorial, elevated IVC pressure is accepted to be the primary cause of Fontan's high mortality and morbidity. This study presents a self-powered venous ejector pump (VEP) that can be used to lower the high IVC venous pressure in single-ventricle patients. METHODS A self-powered venous assist device that exploits the high-energy aortic flow to lower IVC pressure is designed. The proposed design is clinically feasible, simple in structure, and is powered intracorporeally. The device's performance in reducing IVC pressure is assessed by conducting comprehensive computational fluid dynamics simulations in idealized total cavopulmonary connections with different offsets. The device was finally applied to complex 3D reconstructed patient-specific TCPC models to validate its performance. RESULTS The assist device provided a significant IVC pressure drop of more than 3.2 mm Hg in both idealized and patient-specific geometries, while maintaining a high systemic oxygen saturation of more than 90%. The simulations revealed no significant caval pressure rise (< 0.1 mm Hg) and sufficient systemic oxygen saturation (> 84%) in the event of device failure, demonstrating its fail-safe feature. CONCLUSIONS A self-powered venous assist with promising in silico performance in improving Fontan hemodynamics is proposed. Due to its passive nature, the device has the potential to provide palliation for the growing population of patients with failing Fontan.
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Affiliation(s)
- Reza Rasooli
- Department of Energy Resources, Faculty of Science and Technology, University of Stavanger, 4036, Stavanger, Norway.
| | - Knut Erik Teigen Giljarhus
- Department of Mechanical and Structural Engineering and Materials Science, University of Stavanger, 4036, Stavanger, Norway
| | - Aksel Hiorth
- Department of Energy Resources, Faculty of Science and Technology, University of Stavanger, 4036, Stavanger, Norway
| | - Ingunn Westvik Jolma
- Department of Chemistry, Bioscience and Environmental Engineering, University of Stavanger, 4036, Stavanger, Norway
| | | | - Charlotte de Lange
- Department of Paediatric Radiology, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Henrik Brun
- Section for Medical Cybernetics and Image Processing, The Intervention Centre, Oslo University Hospital Rikshospitalet, Oslo, Norway
- Department of Paediatric Cardiology, Division of Paediatric and Adolescent Medicine, Oslo University Hospital, Oslo, Norway
| | - Henrik Holmstrom
- Department of Paediatric Cardiology, Division of Paediatric and Adolescent Medicine, Oslo University Hospital, Oslo, Norway
- Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
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12
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A computational study of aortic reconstruction in single ventricle patients. Biomech Model Mechanobiol 2023; 22:357-377. [PMID: 36335184 PMCID: PMC10174275 DOI: 10.1007/s10237-022-01650-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Accepted: 10/12/2022] [Indexed: 11/06/2022]
Abstract
Patients with hypoplastic left heart syndrome (HLHS) are born with an underdeveloped left heart. They typically receive a sequence of surgeries that result in a single ventricle physiology called the Fontan circulation. While these patients usually survive into early adulthood, they are at risk for medical complications, partially due to their lower than normal cardiac output, which leads to insufficient cerebral and gut perfusion. While clinical imaging data can provide detailed insight into cardiovascular function within the imaged region, it is difficult to use these data for assessing deficiencies in the rest of the body and for deriving blood pressure dynamics. Data from patients used in this paper include three-dimensional, magnetic resonance angiograms (MRA), time-resolved phase contrast cardiac magnetic resonance images (4D-MRI) and sphygmomanometer blood pressure measurements. The 4D-MRI images provide detailed insight into velocity and flow in vessels within the imaged region, but they cannot predict flow in the rest of the body, nor do they provide values of blood pressure. To remedy these limitations, this study combines the MRA, 4D-MRI, and pressure data with 1D fluid dynamics models to predict hemodynamics in the major systemic arteries, including the cerebral and gut vasculature. A specific focus is placed on studying the impact of aortic reconstruction occurring during the first surgery that results in abnormal vessel morphology. To study these effects, we compare simulations for an HLHS patient with simulations for a matched control patient that has double outlet right ventricle (DORV) physiology with a native aorta. Our results show that the HLHS patient has hypertensive pressures in the brain as well as reduced flow to the gut. Wave intensity analysis suggests that the HLHS patient has irregular circulatory function during light upright exercise conditions and that predicted wall shear stresses are lower than normal, suggesting the HLHS patient may have hypertension.
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13
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Zhang Y, Fang M, Wang Z, Liu Y, Zhang C, Wang Z, Wang H. The prediction and verification of outcome of extracardiac conduits fontan based on computational fluid dynamics simulation. Front Physiol 2022; 13:1078140. [PMID: 36505086 PMCID: PMC9729743 DOI: 10.3389/fphys.2022.1078140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Accepted: 11/14/2022] [Indexed: 11/25/2022] Open
Abstract
Objective: This study applied preoperative computed tomography angiography (CTA) and computational fluid dynamics (CFD) simulation to predicte and verify the outcome of Y-shaped extracardiac conduits Fontan for functional single ventricle. Methods: Based on the preoperative CTA data of functional single ventricle (FSV), 4 types of spatial structures of extracardiac conduits were designed for 4 experimental groups: Group A, a traditional TCPC group (20 mm); Group B, a diameter-preserving Y-shaped TCPC (YCPC) group (branch 10 mm); Group C, YCPC group (branch 12 mm); and Group D, an area-preserving YCPC group (branch14 mm). Four indicators including flow velocity, pressure gradient (PG), energy efficiency and inferior vena cava (IVC) blood flow distribution were compared. The optimal procedure was applied. The radionuclide lung perfusion, CTA, echocardiography, cardiovascular angiography and catheterization were performed postoperatively. Results: There were the lowest PG, the lowest flow velocity of branches, the highest energy efficiency, and a relatively balanced and stable distribution of IVC flow for group D. Subsequently, the group D, a handcrafted Y-shaped conduit (14 mm) was used for the YCPC procedure. There was no postoperative PG between the conduit and pulmonary artery with normal pressure and resistance. IVC flow was distributed uniformly. Conclusion: CTA-based CFD provided more guidance for the clinical application of TCPC. A comprehensive surgical design could bring good postoperative outcome. Area-preserving YCPC has more advantages than TCPC and the diameter-preserving YCPC. The study effectively improved the feasibility of clinical applications of YCPC.
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14
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Ahmad Z, Jin LH, Penny DJ, Rusin CG, Peskin CS, Puelz C. Optimal Fenestration of the Fontan Circulation. Front Physiol 2022; 13:867995. [PMID: 35846014 PMCID: PMC9280082 DOI: 10.3389/fphys.2022.867995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 05/13/2022] [Indexed: 11/20/2022] Open
Abstract
In this paper, we develop a pulsatile compartmental model of the Fontan circulation and use it to explore the effects of a fenestration added to this physiology. A fenestration is a shunt between the systemic and pulmonary veins that is added either at the time of Fontan conversion or at a later time for the treatment of complications. This shunt increases cardiac output and decreases systemic venous pressure. However, these hemodynamic benefits are achieved at the expense of a decrease in the arterial oxygen saturation. The model developed in this paper incorporates fenestration size as a parameter and describes both blood flow and oxygen transport. It is calibrated to clinical data from Fontan patients, and we use it to study the impact of a fenestration on several hemodynamic variables, including systemic oxygen availability, effective oxygen availability, and systemic venous pressure. In certain scenarios corresponding to high-risk Fontan physiology, we demonstrate the existence of a range of fenestration sizes in which the systemic oxygen availability remains relatively constant while the systemic venous pressure decreases.
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Affiliation(s)
- Zan Ahmad
- Courant Institute of Mathematical Sciences, New York University, New York, NY, United States
| | - Lynn H. Jin
- Courant Institute of Mathematical Sciences, New York University, New York, NY, United States
- School of Physics, Georgia Institute of Technology, Atlanta, GA, United States
| | - Daniel J. Penny
- Department of Pediatrics, Section of Cardiology, Baylor College of Medicine and Texas Children’s Hospital, Houston, TX, United States
| | - Craig G. Rusin
- Department of Pediatrics, Section of Cardiology, Baylor College of Medicine and Texas Children’s Hospital, Houston, TX, United States
| | - Charles S. Peskin
- Courant Institute of Mathematical Sciences, New York University, New York, NY, United States
| | - Charles Puelz
- Courant Institute of Mathematical Sciences, New York University, New York, NY, United States
- Department of Pediatrics, Section of Cardiology, Baylor College of Medicine and Texas Children’s Hospital, Houston, TX, United States
- *Correspondence: Charles Puelz,
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15
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Khinsoe G, Bappoo N, Kelsey LJ, Blom D, Doyle BJ, Jansen S. Computational biomechanics: a potential new tool for the vascular surgeon in personalized management. ANZ J Surg 2022; 92:1308-1311. [PMID: 35688636 DOI: 10.1111/ans.17476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2021] [Revised: 11/16/2021] [Accepted: 12/21/2021] [Indexed: 11/29/2022]
Affiliation(s)
- Georgia Khinsoe
- Vascular Engineering Laboratory, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands and the UWA Centre for Medical Research, The University of Western Australia, Perth, Western Australia, Australia.,School of Engineering, The University of Western Australia, Perth, Western Australia, Australia
| | - Nikhilesh Bappoo
- Vascular Engineering Laboratory, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands and the UWA Centre for Medical Research, The University of Western Australia, Perth, Western Australia, Australia.,School of Engineering, The University of Western Australia, Perth, Western Australia, Australia
| | - Lachlan J Kelsey
- Vascular Engineering Laboratory, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands and the UWA Centre for Medical Research, The University of Western Australia, Perth, Western Australia, Australia.,School of Engineering, The University of Western Australia, Perth, Western Australia, Australia
| | - Dirk Blom
- Vascular Engineering Laboratory, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands and the UWA Centre for Medical Research, The University of Western Australia, Perth, Western Australia, Australia.,Curtin Medical School, Curtin University, Perth, Western Australia, Australia
| | - Barry J Doyle
- Vascular Engineering Laboratory, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands and the UWA Centre for Medical Research, The University of Western Australia, Perth, Western Australia, Australia.,School of Engineering, The University of Western Australia, Perth, Western Australia, Australia.,Centre for Cardiovascular Science, Queens Medical Research Institute, University of Edinburgh, Edinburgh, UK.,Australian Research Council Centre for Personalised Therapeutics Technologies, Australia
| | - Shirley Jansen
- Curtin Medical School, Curtin University, Perth, Western Australia, Australia.,Heart and Vascular Research Institute, Harry Perkins Institute of Medical Research, QEII Medical Centre, Perth, Western Australia, Australia.,Department of Vascular and Endovascular Surgery, Sir Charles Gardiner Hospital, Perth, Western Australia, Australia.,Medical School, The University of Western Australia, Perth, Western Australia, Australia
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16
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Tobin N, Good BC, Plasencia JD, Fogel MA, Weiss WJ, Manning KB. Computational Investigation of Anastomosis Options of a Right-Heart Pump to Patient Specific Pulmonary Arteries. Ann Biomed Eng 2022; 50:929-940. [PMID: 35451680 DOI: 10.1007/s10439-022-02969-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 04/12/2022] [Indexed: 11/30/2022]
Abstract
Patients with Fontan circulation have increased risk of heart failure, but are not always candidates for heart transplant, leading to the development of the subpulmonic Penn State Fontan Circulation Assist Device. The aim of this study was to use patient-specific computational fluid dynamics simulations to evaluate anastomosis options for implanting this device. Simulations were performed of the pre-surgical anatomy as well as four surgical options: a T-junction and three Y-grafts. Cases were evaluated based on several fluid-dynamic quantities. The impact of imbalanced left-right pulmonary flow distribution was also investigated. Results showed that a 12-mm Y-graft was the most energy efficient. However, an 8-mm graft showed more favorable wall shear stress distribution, indicating lower risk of thrombosis and endothelial damage. The 8-mm Y-grafts also showed a more balanced pulmonary flow split, and lower residence time, also indicating lower thrombosis risk. The relative performance of the surgical options was largely unchanged whether or not the pulmonary vascular resistance remained imbalanced post-implantation.
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Affiliation(s)
- Nicolas Tobin
- Department of Biomedical Engineering, The Pennsylvania State University, 122 Chemical and Biomedical Engineering Building, University Park, PA, 16802-4400, USA
| | - Bryan C Good
- Department of Biomedical Engineering, The Pennsylvania State University, 122 Chemical and Biomedical Engineering Building, University Park, PA, 16802-4400, USA
| | | | - Mark A Fogel
- Division of Cardiology, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - William J Weiss
- Department of Surgery, Penn State Hershey Medical Center, Hershey, PA, 17033, USA
| | - Keefe B Manning
- Department of Biomedical Engineering, The Pennsylvania State University, 122 Chemical and Biomedical Engineering Building, University Park, PA, 16802-4400, USA. .,Department of Surgery, Penn State Hershey Medical Center, Hershey, PA, 17033, USA.
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17
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In Vitro Measurement of Hepatic Flow Distribution in Fontan Vascular Conduits: Towards Rapid Validation Techniques. J Biomech 2022; 137:111092. [DOI: 10.1016/j.jbiomech.2022.111092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 04/08/2022] [Accepted: 04/08/2022] [Indexed: 11/24/2022]
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18
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Prather R, Das A, Farias M, Divo E, Kassab A, DeCampli W. Parametric investigation of an injection-jet self-powered Fontan circulation. Sci Rep 2022; 12:2161. [PMID: 35140260 PMCID: PMC8828777 DOI: 10.1038/s41598-022-05985-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 01/17/2022] [Indexed: 12/04/2022] Open
Abstract
Approximately \documentclass[12pt]{minimal}
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\begin{document}$$1/2500$$\end{document}1/2500 babies are born with only one functioning ventricle and the Fontan is the third and, ideally final staged palliative operation for these patients. This altered circulation is prone to failure with survival rates below \documentclass[12pt]{minimal}
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\begin{document}$$50\%$$\end{document}50% into adulthood. Chronically elevated inferior vena cava (IVC) pressure is implicated as one cause of the mortality and morbidity in this population. An injection jet shunt (IJS) drawing blood-flow directly from the aortic arch to significantly lower IVC pressure is proposed. A computer-generated 3D model of a 2–4 year old patient with a fenestrated Fontan and a cardiac output of 2.3 L/min was generated. The detailed 3D pulsatile hemodynamics are resolved in a zero-dimensional lumped parameter network tightly-coupled to a 3D computational fluid dynamics model accounting for non-Newtonian blood rheology and resolving turbulence using large eddy simulation. IVC pressure and systemic oxygen saturation were tracked for various IJS-assisted Fontan configurations, altering design parameters such as shunt and fenestration diameters and locations. A baseline “failing” Fontan with a 4 mm fenestration was tuned to have an elevated IVC pressure (+ 17.8 mmHg). Enlargement of the fenestration to 8 mm resulted in a 3 mmHg IVC pressure drop but an unacceptable reduction in systemic oxygen saturation below 80%. Addition of an IJS with a 2 mm nozzle and minor volume load to the ventricle improved the IVC pressure drop to 3.2 mmHg while increasing systemic oxygen saturation above 80%. The salutary effects of the IJS to effectively lower IVC pressure while retaining acceptable levels of oxygen saturation are successfully demonstrated.
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Affiliation(s)
- Ray Prather
- Department of Mechanical and Aerospace Engineering, University of Central Florida, 4000 Central Florida Blvd., Orlando, FL, 32816, USA. .,Department of Mechanical Engineering, Embry-Riddle Aeronautical University, 1 Aerospace Blvd., Daytona Beach, FL, 32114, USA. .,The Heart Center, Arnold Palmer Hospital for Children, 92 West Miller Street, Orlando, FL, 32806, USA.
| | - Arka Das
- Department of Mechanical Engineering, Embry-Riddle Aeronautical University, 1 Aerospace Blvd., Daytona Beach, FL, 32114, USA
| | - Michael Farias
- The Heart Center, Arnold Palmer Hospital for Children, 92 West Miller Street, Orlando, FL, 32806, USA
| | - Eduardo Divo
- Department of Mechanical Engineering, Embry-Riddle Aeronautical University, 1 Aerospace Blvd., Daytona Beach, FL, 32114, USA
| | - Alain Kassab
- Department of Mechanical and Aerospace Engineering, University of Central Florida, 4000 Central Florida Blvd., Orlando, FL, 32816, USA
| | - William DeCampli
- The Heart Center, Arnold Palmer Hospital for Children, 92 West Miller Street, Orlando, FL, 32806, USA.,College of Medicine, University of Central Florida, 6850 Lake Nona Blvd, Orlando, FL, 32827, USA
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19
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Liu X, Kim B, Loke YH, Mass P, Olivieri L, Hibino N, Fuge M, Krieger A. Semi-Automatic Planning and Three-Dimensional Electrospinning of Patient-Specific Grafts for Fontan Surgery. IEEE Trans Biomed Eng 2022; 69:186-198. [PMID: 34156934 PMCID: PMC8753752 DOI: 10.1109/tbme.2021.3091113] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
This paper proposes a semi-automatic Fontan surgery planning method for designing and manufacturing hemodynamically optimized patient-specific grafts. Fontan surgery is a palliative procedure for patients with a single ventricle heart defect by creating a new path using a vascular graft for the deoxygenated blood to be directed to the lungs, bypassing the heart. However, designing patient-specific grafts with optimized hemodynamic performance is a complex task due to the variety of patient-specific anatomies, confined surgical planning space, and the requirement of simultaneously considering multiple design criteria for vascular graft optimization. To address these challenges, we used parameterized Fontan pathways to explore patient-specific vascular graft design spaces and search for optimal solutions by formulating a nonlinear constrained optimization problem, which minimizes indexed power loss (iPL) of the Fontan model by constraining hepatic flow distribution (HFD), percentage of abnormal wall shear stress (%WSS) and geometric interference between Fontan pathways and the heart models (InDep) within clinically acceptable thresholds. Gaussian process regression was employed to build surrogate models of the hemodynamic parameters as well as InDep and [Formula: see text] (conduit model smoothness indicator) for optimization by pattern search. We tested the proposed method on two patient-specific models (n=2). The results showed the automatically optimized (AutoOpt) Fontan models hemodynamically outperformed or at least are comparable to manually optimized Fontan models with significantly reduced surgical planning time (15 hours versus over 2 weeks). We also demonstrated feasibility of manufacturing the AutoOpt Fontan conduits by using electrospun nanofibers.
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Affiliation(s)
- Xiaolong Liu
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD, USA,Department of Mechanical Engineering, University of Maryland, College Park, MD, USA
| | - Byeol Kim
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD, USA,Department of Mechanical Engineering, University of Maryland, College Park, MD, USA
| | - Yue-Hin Loke
- Division of Cardiology, Children’s National Hospital, Washington DC, USA
| | - Paige Mass
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Children’s National Hospital, Washington DC, USA
| | - Laura Olivieri
- Division of Cardiology, Children’s National Hospital, Washington DC, USA,Sheikh Zayed Institute for Pediatric Surgical Innovation, Children’s National Hospital, Washington DC, USA
| | - Narutoshi Hibino
- Section of Cardiac Surgery, Department of Surgery, The University of Chicago Medicine, Chicago, IL, USA,Division of Cardiac Surgery, Johns Hopkins Hospital, Baltimore, MD, USA
| | - Mark Fuge
- Department of Mechanical Engineering, University of Maryland, College Park, MD, USA
| | - Axel Krieger
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD, USA,Department of Mechanical Engineering, University of Maryland, College Park, MD, USA
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20
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Camarda JA, Dholakia RJ, Wang H, Samyn MM, Cava JR, LaDisa JF. A Pilot Study Characterizing Flow Patterns in the Thoracic Aorta of Patients With Connective Tissue Disease: Comparison to Age- and Gender-Matched Controls via Fluid Structure Interaction. Front Pediatr 2022; 10:772142. [PMID: 35601426 PMCID: PMC9114664 DOI: 10.3389/fped.2022.772142] [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: 09/07/2021] [Accepted: 03/25/2022] [Indexed: 12/02/2022] Open
Abstract
Prior computational and imaging studies described changes in flow patterns for patients with Marfan syndrome, but studies are lacking for related populations. This pilot study addresses this void by characterizing wall shear stress (WSS) indices for patients with Loeys-Dietz and undifferentiated connective tissue diseases. Using aortic valve-based velocity profiles from magnetic resonance imaging as input to patient-specific fluid structure interaction (FSI) models, we determined local flow patterns throughout the aorta for four patients with various connective tissue diseases (Loeys-Dietz with the native aorta, connective tissue disease of unclear etiology with native aorta in female and male patients, and an untreated patient with Marfan syndrome, as well as twin patients with Marfan syndrome who underwent valve-sparing root replacement). FSI simulations used physiological boundary conditions and material properties to replicate available measurements. Time-averaged WSS (TAWSS) and oscillatory shear index (OSI) results are presented with localized comparison to age- and gender-matched control participants. Ascending aortic dimensions were greater in almost all patients with connective tissue diseases relative to their respective control. Differences in TAWSS and OSI were driven by local morphological differences and cardiac output. For example, the model for one twin had a more pronounced proximal descending aorta in the vicinity of the ductus ligamentum that impacted WSS indices relative to the other. We are optimistic that the results of this study can serve as a foundation for larger future studies on the connective tissue disorders presented in this article.
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Affiliation(s)
- Joseph A Camarda
- Department of Pediatrics, Division of Cardiology, Herma Heart Institute, Children's Wisconsin and the Medical College of Wisconsin, Milwaukee, WI, United States
| | - Ronak J Dholakia
- Department of Biomedical Engineering, Marquette University the Medical College of Wisconsin, Milwaukee, WI, United States
| | - Hongfeng Wang
- Department of Biomedical Engineering, Marquette University the Medical College of Wisconsin, Milwaukee, WI, United States
| | - Margaret M Samyn
- Department of Pediatrics, Division of Cardiology, Herma Heart Institute, Children's Wisconsin and the Medical College of Wisconsin, Milwaukee, WI, United States.,Department of Biomedical Engineering, Marquette University the Medical College of Wisconsin, Milwaukee, WI, United States
| | - Joseph R Cava
- Department of Pediatrics, Division of Cardiology, Herma Heart Institute, Children's Wisconsin and the Medical College of Wisconsin, Milwaukee, WI, United States
| | - John F LaDisa
- Department of Pediatrics, Division of Cardiology, Herma Heart Institute, Children's Wisconsin and the Medical College of Wisconsin, Milwaukee, WI, United States.,Department of Biomedical Engineering, Marquette University the Medical College of Wisconsin, Milwaukee, WI, United States.,Departments of Medicine, Division of Cardiovascular Medicine and Physiology, Medical College of Wisconsin, Milwaukee, WI, United States
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21
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Lashkarinia SS, Cicek M, Kose B, Rezaeimoghaddam M, Yılmaz EH, Aydemir NA, Rasooli R, Ozkok S, Yurtseven N, Erdem H, Pekkan K, Sasmazel A. OUP accepted manuscript. Interact Cardiovasc Thorac Surg 2022; 34:1095-1105. [PMID: 35134949 PMCID: PMC9159461 DOI: 10.1093/icvts/ivac001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 10/21/2021] [Accepted: 01/14/2022] [Indexed: 11/23/2022] Open
Affiliation(s)
| | - Murat Cicek
- Department of Cardiovascular Surgery, Dr. Siyami Ersek Thoracic and Cardiovascular Surgery Training and Research Hospital, Istanbul, Turkey
| | - Banu Kose
- Department of Biomedical Engineering, Istanbul Medipol University, Istanbul, Turkey
| | | | - Emine Hekim Yılmaz
- Department of Cardiovascular Surgery, Dr. Siyami Ersek Thoracic and Cardiovascular Surgery Training and Research Hospital, Istanbul, Turkey
| | - Numan Ali Aydemir
- Department of Cardiovascular Surgery, Dr. Siyami Ersek Thoracic and Cardiovascular Surgery Training and Research Hospital, Istanbul, Turkey
| | - Reza Rasooli
- Department of Mechanical Engineering, Koc University, Istanbul, Turkey
| | - Sercin Ozkok
- Research Hospital Radiology Department, Medeniyet University Goztepe Training, Istanbul, Turkey
| | - Nurgul Yurtseven
- Anesthesiology, Pediatric Cardiac Intensive Care Unit, Dr. Siyami Ersek Thoracic and Cardiovascular Surgery Training and Research Hospital, Istanbul, Turkey
| | - Hasan Erdem
- Department of Cardiovascular Surgery, Kosuyolu Yuksek Ihtisas Training and Research Hospital, Istanbul, Turkey
| | - Kerem Pekkan
- Department of Mechanical Engineering, Koc University, Istanbul, Turkey
- Mechanical Engineering Department Koç University Rumeli Feneri Campus, Sarıyer, 34450 Istanbul, Turkey. Tel: +90-(533)-356-35-95; e-mail: (K.Pekkan)
| | - Ahmet Sasmazel
- Department of Cardiovascular Surgery, Dr. Siyami Ersek Thoracic and Cardiovascular Surgery Training and Research Hospital, Istanbul, Turkey
- Corresponding author. Pediatric Cardiovascular Surgery, Dr. Siyami Ersek Thoracic and Cardiovascular Surgery Research Hospital, Tibbiye Cad. No: 13, Uskudar, 34668 Istanbul,Turkey. Tel: +90-(216)-542-44-44; e-mail: (A. Sasmazel)
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22
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Kim B, Nguyen P, Loke YH, Cleveland V, Liu X, Mass P, Hibino N, Olivieri L, Krieger A. CorFix: Virtual Reality Cardiac Surgical Planning Software for Designing Patient-Specific Vascular Grafts: Development and Pilot Usability Study (Preprint). JMIR Cardio 2021; 6:e35488. [PMID: 35713940 PMCID: PMC9250062 DOI: 10.2196/35488] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 05/05/2022] [Accepted: 05/17/2022] [Indexed: 11/17/2022] Open
Abstract
Background Patients with single ventricle heart defects receive 3 stages of operations culminating in the Fontan procedure. During the Fontan procedure, a vascular graft is sutured between the inferior vena cava and pulmonary artery to divert deoxygenated blood flow to the lungs via passive flow. Customizing the graft configuration can maximize the long-term benefits. However, planning patient-specific procedures has several challenges, including the ability for physicians to customize grafts and evaluate their hemodynamic performance. Objective The aim of this study was to develop a virtual reality (VR) Fontan graft modeling and evaluation software for physicians. A user study was performed to achieve 2 additional goals: (1) to evaluate the software when used by medical doctors and engineers, and (2) to explore the impact of viewing hemodynamic simulation results in numerical and graphical formats. Methods A total of 5 medical professionals including 4 physicians (1 fourth-year resident, 1 third-year cardiac fellow, 1 pediatric intensivist, and 1 pediatric cardiac surgeon) and 1 biomedical engineer voluntarily participated in the study. The study was pre-scripted to minimize the variability of the interactions between the experimenter and the participants. All participants were trained to use the VR gear and our software, CorFix. Each participant designed 1 bifurcated and 1 tube-shaped Fontan graft for a single patient. A hemodynamic performance evaluation was then completed, allowing the participants to further modify their tube-shaped design. The design time and hemodynamic performance for each graft design were recorded. At the end of the study, all participants were provided surveys to evaluate the usability and learnability of the software and rate the intensity of VR sickness. Results The average times for creating 1 bifurcated and 1 tube-shaped graft after a single 10-minute training session were 13.40 and 5.49 minutes, respectively, with 3 out 5 bifurcated and 1 out of 5 tube-shaped graft designs being in the benchmark range of hepatic flow distribution. Reviewing hemodynamic performance results and modifying the tube-shaped design took an average time of 2.92 minutes. Participants who modified their tube-shaped graft designs were able to improve the nonphysiologic wall shear stress (WSS) percentage by 7.02%. All tube-shaped graft designs improved the WSS percentage compared to the native surgical case of the patient. None of the designs met the benchmark indexed power loss. Conclusions VR graft design software can quickly be taught to physicians with no engineering background or VR experience. Improving the CorFix system could improve performance of the users in customizing and optimizing grafts for patients. With graphical visualization, physicians were able to improve WSS percentage of a tube-shaped graft, lowering the chance of thrombosis. Bifurcated graft designs showed potential strength in better flow split to the lungs, reducing the risk for pulmonary arteriovenous malformations.
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Affiliation(s)
- Byeol Kim
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD, United States
| | - Phong Nguyen
- Department of Computer Science, University of Maryland, College Park, MD, United States
| | - Yue-Hin Loke
- Division of Cardiology, Children's National Hospital, Washington, DC, United States
| | - Vincent Cleveland
- Division of Cardiology, Children's National Hospital, Washington, DC, United States
| | - Xiaolong Liu
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD, United States
| | - Paige Mass
- Division of Cardiology, Children's National Hospital, Washington, DC, United States
| | - Narutoshi Hibino
- Department of Surgery, University of Chicago, Chicago, IL, United States
| | - Laura Olivieri
- Division of Cardiology, Children's National Hospital, Washington, DC, United States
| | - Axel Krieger
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD, United States
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23
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In-Vitro Validation of Self-Powered Fontan Circulation for Treatment of Single Ventricle Anomaly. FLUIDS 2021. [DOI: 10.3390/fluids6110401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Around 8% of all newborns with a Congenital Heart Defect (CHD) have only a single functioning ventricle. The Fontan operation has served as palliation for this anomaly for decades, but the surgery entails multiple complications, and the survival rate is less than 50% by adulthood. A rapidly testable novel alternative is proposed by creating a bifurcating graft, or Injection Jet Shunt (IJS), used to “entrain” the pulmonary flow and thus provide assistance while reducing the caval pressure. A dynamically scaled Mock Flow Loop (MFL) has been configured to validate this hypothesis. Three IJS nozzles of varying diameters 2, 3, and 4 mm with three aortic anastomosis angles and pulmonary vascular resistance (PVR) reduction have been tested to validate the hypothesis and optimize the caval pressure reduction. The MFL is based on a Lumped-Parameter Model (LPM) of a non-fenestrated Fontan circulation. The best outcome was achieved with the experimental testing of a 3 mm IJS by producing an average caval pressure reduction of more than 5 mmHg while maintaining the clinically acceptable pulmonary flow rate (Qp) to systemic flow rate (Qs) ratio of ~1.5. Furthermore, alteration of the PVR helped in achieving higher caval pressure reduction with the 3 mm IJS at the expense of an increase in Qp/Qs ratio.
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24
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Gupta A, Gillett C, Gerard P, Cheung MMH, Mynard JP, Kung E. Predictive Models for Pulmonary Artery Size in Fontan Patients. J Cardiovasc Transl Res 2021; 14:782-789. [PMID: 32248348 DOI: 10.1007/s12265-020-09993-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 03/18/2020] [Indexed: 11/28/2022]
Abstract
We developed models of pulmonary artery (PA) size in Fontan patients as a function of age and body surface area (BSA) using linear regression and breakpoint analyses based on data from 43 Fontan patients divided into two groups: the extracardiac conduit (ECC) group (n = 24) and the non-ECC group (n = 19). Model predictions were compared against those of a non-Fontan control group (n = 18) and published literature. We observed strong positive correlations of the mean PA diameter with BSA (r = 0.9, p < 0.05) and age (r = 0.88, p < 0.05) in the ECC group. The absolute percentage differences between our BSA and age model predictions against published literature were less than 16% and 20%, respectively. Predicted PA size for Fontan patients was consistently smaller than the control group. These models may serve as useful references for clinicians and be utilized to construct 3D anatomic models that correspond to patient body size or age.
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Affiliation(s)
- Akash Gupta
- Department of Mechanical Engineering, Clemson University, Clemson, SC, 29634-0921, USA
| | - Chris Gillett
- Department of Cardiology, Royal Children's Hospital, Parkville, Victoria, Australia
| | - Patrick Gerard
- School of Mathematical and Statistical Sciences, Clemson University, Clemson, SC, USA
| | - Michael M H Cheung
- Department of Cardiology, Royal Children's Hospital, Parkville, Victoria, Australia
- Heart Research, Murdoch Children's Research Institute, Parkville, Victoria, Australia
- Department of Paediatrics, University of Melbourne, Parkville, Victoria, Australia
| | - Jonathan P Mynard
- Department of Cardiology, Royal Children's Hospital, Parkville, Victoria, Australia
- Heart Research, Murdoch Children's Research Institute, Parkville, Victoria, Australia
- Department of Paediatrics, University of Melbourne, Parkville, Victoria, Australia
- Department of Biomedical Engineering, University of Melbourne, Parkville, Victoria, Australia
| | - Ethan Kung
- Department of Mechanical Engineering, Clemson University, Clemson, SC, 29634-0921, USA.
- Department of Bioengineering, Clemson University, Clemson, SC, USA.
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25
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Schwarz EL, Kelly JM, Blum KM, Hor KN, Yates AR, Zbinden JC, Verma A, Lindsey SE, Ramachandra AB, Szafron JM, Humphrey JD, Shin'oka T, Marsden AL, Breuer CK. Hemodynamic performance of tissue-engineered vascular grafts in Fontan patients. NPJ Regen Med 2021; 6:38. [PMID: 34294733 PMCID: PMC8298568 DOI: 10.1038/s41536-021-00148-w] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Accepted: 06/11/2021] [Indexed: 02/06/2023] Open
Abstract
In the field of congenital heart surgery, tissue-engineered vascular grafts (TEVGs) are a promising alternative to traditionally used synthetic grafts. Our group has pioneered the use of TEVGs as a conduit between the inferior vena cava and the pulmonary arteries in the Fontan operation. The natural history of graft remodeling and its effect on hemodynamic performance has not been well characterized. In this study, we provide a detailed analysis of the first U.S. clinical trial evaluating TEVGs in the treatment of congenital heart disease. We show two distinct phases of graft remodeling: an early phase distinguished by rapid changes in graft geometry and a second phase of sustained growth and decreased graft stiffness. Using clinically informed and patient-specific computational fluid dynamics (CFD) simulations, we demonstrate how changes to TEVG geometry, thickness, and stiffness affect patient hemodynamics. We show that metrics of patient hemodynamics remain within normal ranges despite clinically observed levels of graft narrowing. These insights strengthen the continued clinical evaluation of this technology while supporting recent indications that reversible graft narrowing can be well tolerated, thus suggesting caution before intervening clinically.
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Affiliation(s)
- Erica L Schwarz
- Department of Bioengineering, Stanford University, Stanford, CA, USA.
| | - John M Kelly
- Center for Regenerative Medicine, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
- The Heart Center, Nationwide Children's Hospital, Columbus, OH, USA
| | - Kevin M Blum
- Center for Regenerative Medicine, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, USA
| | - Kan N Hor
- The Heart Center, Nationwide Children's Hospital, Columbus, OH, USA
- Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Andrew R Yates
- The Heart Center, Nationwide Children's Hospital, Columbus, OH, USA
- Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Jacob C Zbinden
- Center for Regenerative Medicine, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, USA
| | - Aekaansh Verma
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Stephanie E Lindsey
- Department of Bioengineering, Stanford University, Stanford, CA, USA
- Department of Pediatrics, Stanford University, Stanford, CA, USA
| | | | - Jason M Szafron
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - Jay D Humphrey
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - Toshiharu Shin'oka
- Center for Regenerative Medicine, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
- The Heart Center, Nationwide Children's Hospital, Columbus, OH, USA
- Department of Cardiothoracic Surgery, Nationwide Children's Hospital, Columbus, OH, USA
| | - Alison L Marsden
- Department of Bioengineering, Stanford University, Stanford, CA, USA
- Department of Pediatrics, Stanford University, Stanford, CA, USA
| | - Christopher K Breuer
- Center for Regenerative Medicine, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
- Department of Surgery, The Ohio State University Wexner Medical Center, Columbus, OH, USA
- Department of Surgery, Nationwide Children's Hospital, Columbus, OH, USA
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26
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Jia D, Peroni M, Khalapyan T, Esmaily M. An Efficient Assisted Bidirectional Glenn Design With Lowered Superior Vena Cava Pressure for Stage-One Single Ventricle Patients. J Biomech Eng 2021; 143:071008. [PMID: 33590839 DOI: 10.1115/1.4050170] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Indexed: 11/08/2022]
Abstract
Recently, the assisted bidirectional Glenn (ABG) procedure has been proposed as an alternative to the modified Blalock-Taussig shunt (mBTS) operation for neonates with single-ventricle physiology. Despite success in reducing heart workload and maintaining sufficient pulmonary flow, the ABG also raised the superior vena cava (SVC) pressure to a level that may not be tolerated by infants. To lower the SVC pressure, we propose a modified version of the ABG (mABG), in which a shunt with a slit-shaped nozzle exit is inserted at the junction of the right and left brachiocephalic veins. The proposed operation is compared against the ABG, the mBTS, and the bidirectional Glenn (BDG) operations using closed-loop multiscale simulations. Both normal (2.3 Wood units-m2) and high (7 Wood units-m2) pulmonary vascular resistance (PVR) values are simulated. The mABG provides the highest oxygen saturation, oxygen delivery, and pulmonary flow rate in comparison to the BDG and the ABG. At normal PVR, the SVC pressure is significantly reduced below that of the ABG and the BDG (mABG: 4; ABG: 8; BDG: 6; mBTS: 3 mmHg). However, the SVC pressure remains high at high PVR (mABG: 15; ABG: 16; BDG: 12; mBTS: 3 mmHg), motivating an optimization study to improve the ABG hemodynamics efficiency for a broader range of conditions in the future. Overall, the mABG preserves all advantages of the original ABG procedure while reducing the SVC pressure at normal PVR.
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Affiliation(s)
- Dongjie Jia
- Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY 14850
| | - Matthew Peroni
- Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY 14850
| | | | - Mahdi Esmaily
- Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY 14850
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27
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A Tribute to Ajit Yoganathan's Cardiovascular Fluid Mechanics Lab: A Survey of Its Contributions to Our Understanding of the Physiology and Management of Single-Ventricle Patients. Cardiovasc Eng Technol 2021; 12:631-639. [PMID: 34018153 DOI: 10.1007/s13239-021-00540-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 04/30/2021] [Indexed: 12/29/2022]
Abstract
INTRODUCTION Among patients with congenital heart disease, those born with only a single working ventricle represent a particularly complex sub-population, typically requiring multiple surgeries and suffering from high levels of mortality and morbidity. Their cardiac care is complex and has evolved considerably since surgical palliation was first introduced more than 50 years ago. Improvements in treatment have been driven both by growing clinical experience and by knowledge gained through experimental and computational studies of blood flow in these patients. The Cardiovascular Fluid Mechanics Lab at the Georgia Institute of Technology, founded 30 years ago by Dr. Ajit Yoganathan, has pioneered work in this field. METHODS In this review, key contributions of Dr. Yoganathan's Cardiovascular Fluid Dynamics Lab are surveyed, including experimental flow loop studies as well as computational fluid dynamics analyses that address many of the critical challenges that cardiologists and surgeons face in treating these patients, including how to reconstruct cardiovascular anatomy to minimize power loss, balance blood flow distribution at key bifurcation points, and avoid other unfavorable hemodynamic conditions. CONCLUSIONS Among many contributions in this field, work from the Cardiovascular Fluid Mechanics Lab has led to novel medical devices and patient-specific computational modeling workflows and software tools. These key contributions from this group have enhanced our understanding of the physiology and management of single-ventricle patients.
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28
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CRIMSON: An open-source software framework for cardiovascular integrated modelling and simulation. PLoS Comput Biol 2021; 17:e1008881. [PMID: 33970900 PMCID: PMC8148362 DOI: 10.1371/journal.pcbi.1008881] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 05/25/2021] [Accepted: 03/17/2021] [Indexed: 12/16/2022] Open
Abstract
In this work, we describe the CRIMSON (CardiovasculaR Integrated Modelling and SimulatiON) software environment. CRIMSON provides a powerful, customizable and user-friendly system for performing three-dimensional and reduced-order computational haemodynamics studies via a pipeline which involves: 1) segmenting vascular structures from medical images; 2) constructing analytic arterial and venous geometric models; 3) performing finite element mesh generation; 4) designing, and 5) applying boundary conditions; 6) running incompressible Navier-Stokes simulations of blood flow with fluid-structure interaction capabilities; and 7) post-processing and visualizing the results, including velocity, pressure and wall shear stress fields. A key aim of CRIMSON is to create a software environment that makes powerful computational haemodynamics tools accessible to a wide audience, including clinicians and students, both within our research laboratories and throughout the community. The overall philosophy is to leverage best-in-class open source standards for medical image processing, parallel flow computation, geometric solid modelling, data assimilation, and mesh generation. It is actively used by researchers in Europe, North and South America, Asia, and Australia. It has been applied to numerous clinical problems; we illustrate applications of CRIMSON to real-world problems using examples ranging from pre-operative surgical planning to medical device design optimization.
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29
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Wei ZA, Ratnayaka K, Si B, Singh-Gryzbon S, Cetatoiu MA, Fogel MA, Slesnick T, Yoganathan AP, Nigro JJ. An Anterior Anastomosis for the Modified Fontan Connection: A Hemodynamic Analysis. Semin Thorac Cardiovasc Surg 2021; 33:816-823. [PMID: 33662555 DOI: 10.1053/j.semtcvs.2021.01.056] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Accepted: 01/05/2021] [Indexed: 12/25/2022]
Abstract
This hemodynamic feasibility study examined total cavopulmonary connection (TCPC) designs connecting the extracardiac conduit to the anterior surface of pulmonary arteries (PAs) or superior vena cava (SVC) rather than to the inferior PA surface (traditional TCPC). The study involved twenty-five consecutive Fontan patients meeting inclusion criteria from a single institution. A virtual surgical platform mimicked the completed traditional TCPC and generated three anterior anastomosis designs: Anterior-PA, Middle-SVC, and SVC-Inn (Inn: innominate vein). Hemodynamic performance of anterior anastomosis designs was compared with the traditional TCPC regarding indexed power loss (iPL) and hepatic flow distribution (HFD). Compared to the traditional TCPC, the Anterior-PA design produces a similar iPL. The Middle-SVC design is also similar, though the iPL difference is positively correlated with the anastomosing height. The SVC-Inn design had significantly more iPL. The three anterior anastomosis designs did not have a significant difference in HFD (from traditional TCPC). Pulmonary flow distribution (PFD) has a stronger correlation with HFD from the anterior anastomosis designs than the traditional TCPC. This hemodynamic feasibility study examined anterior anastomosis, extracardiac TCPC designs that may offer surgeons clinical dexterity. The Anterior-PA design may be equivalent to the traditional TCPC. Fontan extracardiac conduit anastomosis just superior to the PAs (Middle-SVC) also preserves hemodynamic performance and avoids direct PA anastomosis. These designs could simplify surgical Fontan completion, and may particularly benefit patients requiring surgical dissection, having atypical PA orientation, or after PA stent angioplasty.
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Affiliation(s)
- Zhenglun Alan Wei
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia; Department of Biomedical Engineering, University of Massachusetts Lowell, Lowell, Massachusetts
| | - Kanishka Ratnayaka
- Division of Pediatric Cardiology, Rady Children's Hospital and UC San Diego School of Medicine, San Diego, California
| | - Biao Si
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia
| | - Shelly Singh-Gryzbon
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia
| | | | - Mark A Fogel
- Division of Cardiology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Timothy Slesnick
- Emory University School of Medicine, Children's Healthcare of Atlanta, Atlanta, Georgia
| | - Ajit P Yoganathan
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia.
| | - John J Nigro
- Division of Cardiovascular Surgery, Rady Children's Hospital and UC San Diego School of Medicine, San Diego, California
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30
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Xu F, Johnson EL, Wang C, Jafari A, Yang CH, Sacks MS, Krishnamurthy A, Hsu MC. Computational investigation of left ventricular hemodynamics following bioprosthetic aortic and mitral valve replacement. MECHANICS RESEARCH COMMUNICATIONS 2021; 112:103604. [PMID: 34305195 PMCID: PMC8301225 DOI: 10.1016/j.mechrescom.2020.103604] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
The left ventricle of the heart is a fundamental structure in the human cardiac system that pumps oxygenated blood into the systemic circulation. Several valvular conditions can cause the aortic and mitral valves associated with the left ventricle to become severely diseased and require replacement. However, the clinical outcomes of such operations, specifically the postoperative ventricular hemodynamics of replacing both valves, are not well understood. This work uses computational fluid-structure interaction (FSI) to develop an improved understanding of this effect by modeling a left ventricle with the aortic and mitral valves replaced with bioprostheses. We use a hybrid Arbitrary Lagrangian-Eulerian/immersogeometric framework to accommodate the analysis of cardiac hemodynamics and heart valve structural mechanics in a moving fluid domain. The motion of the endocardium is obtained from a cardiac biomechanics simulation and provided as an input to the proposed numerical framework. The results from the simulations in this work indicate that the replacement of the native mitral valve with a tri-radially symmetric bioprosthesis dramatically changes the ventricular hemodynamics. Most significantly, the vortical motion in the left ventricle is found to reverse direction after mitral valve replacement. This study demonstrates that the proposed computational FSI framework is capable of simulating complex multiphysics problems and can provide an in-depth understanding of the cardiac mechanics.
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Affiliation(s)
- Fei Xu
- Ansys Inc., Austin, TX 78746, USA
| | - Emily L. Johnson
- Department of Mechanical Engineering, Iowa State University, Ames, IA 50011, USA
| | | | - Arian Jafari
- Department of Mechanical Engineering, Iowa State University, Ames, IA 50011, USA
| | - Cheng-Hau Yang
- Department of Mechanical Engineering, Iowa State University, Ames, IA 50011, USA
| | - Michael S. Sacks
- Oden Institute for Computational Engineering and Sciences, The University of Texas at Austin, Austin, TX 78712, USA
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712, USA
| | - Adarsh Krishnamurthy
- Department of Mechanical Engineering, Iowa State University, Ames, IA 50011, USA
| | - Ming-Chen Hsu
- Department of Mechanical Engineering, Iowa State University, Ames, IA 50011, USA
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31
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Fontan Hemodynamics Investigation via Modeling and Experimental Characterization of Idealized Pediatric Total Cavopulmonary Connection. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10196910] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Simulation of the human body normal operating conditions is the important issue in the engineering process of designing biomedical devices intended for implantation. As an example of such process the Fontan procedure aims to support the human body function. It is a standard palliative treatment method for patients with a functionally univentricular heart. Nevertheless, this procedure has significant drawbacks. For instance, overload of the only functional ventricle leads to the inevitability of the heart transplantation. Herein, we perform simulation and experimental characteristics of the pediatric total cavopulmonary connection (TCPC) influence on the blood flow. We investigate and design three different types of pediatric TCPC configurations; we detect fluorescent particles via a high-speed camera in order to analyze distribution of the blood flow velocity modulus in different types of TCPCs. Finally, we evaluate hydraulic power losses for various cases. This work is particularly relevant for the improvement of existing TCPCs quality that can extend the life of Fontan patients. Moreover, it also applies to the reduction of morbidity and mortality of the patients waiting for a heart transplantation.
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32
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Gupta A, Kung E. A protocol for automated a posteriori adaptive meshing with SimVascular: a test case. BMC Res Notes 2020; 13:229. [PMID: 32321572 PMCID: PMC7178633 DOI: 10.1186/s13104-020-05057-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Accepted: 04/04/2020] [Indexed: 11/10/2022] Open
Abstract
OBJECTIVE Operational details regarding the use of the adaptive meshing (AM) algorithm available in the SimVascular package are scarce despite its application in several studies. Lacking these details, novice users of the AM algorithm may experience undesirable outcomes post-adaptation such as increases in mesh error metrics, unpredictable increases in mesh size, and losses in geometric fidelity. Here we present a test case using our proposed iterative protocol that will help prevent these undesirable outcomes and enhance the utility of the AM algorithm. We present three trials (conservative, moderate, and aggressive settings) applied to a scenario modelling a Fontan junction with a patient-specific geometry and physiologically realistic boundary conditions. RESULTS In all three trials, an overall reduction in mesh error metrics is observed (range 47%-86%). The increase in the number of elements through each adaptation never exceeded the mesh size of the pre-adaptation mesh by one order of magnitude. In all three trials, the protocol resulted in consistent, repeatable improvements in mesh error metrics, no losses of geometric fidelity and steady increments in the number of elements in the mesh. Our proposed protocol prevented the aforementioned undesirable outcomes and can potentially save new users considerable effort and computing resources.
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Affiliation(s)
- Akash Gupta
- Department of Mechanical Engineering, Clemson University, Fluor Daniel Building, Clemson, SC, 29634, USA
| | - Ethan Kung
- Department of Mechanical Engineering and Bioengineering, Clemson University, Fluor Daniel Building, Clemson, SC, 29634, USA.
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33
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Contijoch F, Li B, Yang W, Silva-Sepulveda JA, Vodkin I, Printz B, Vavinskaya V, Hegde S, Marsden A, El-Sabrout H, Alshawabkeh L, Moore JW, El-Said H. Exercise MRI highlights heterogeneity in cardiovascular mechanics among patients with Fontan circulation: proposed protocol for routine evaluation. J Thorac Dis 2020; 12:1204-1212. [PMID: 32274201 PMCID: PMC7139092 DOI: 10.21037/jtd.2019.09.59] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 09/17/2019] [Indexed: 11/30/2022]
Abstract
Single ventricle physiology and palliation via the Fontan operation lead to a series of cardiovascular changes. In addition, organs such as the kidneys and liver have been shown to experience insults and subsequent injury. This has led to routine surveillance of patients. We present findings from a small cohort of patients that was deeply phenotyped to illustrate the need for comprehensive evaluation. A cohort of four Fontan patients with fairly high cardiovascular function was recruited 5-10 years post-Fontan. Patients underwent a rigorous clinical work-up after which a research MRI scan was performed during which (I) data were obtained during exercise to evaluate changes in stroke volume during supine exercise and (II) magnetic resonance angiograms with phase-contrast images were obtained for computational modeling of flows through the Fontan circulation at rest. Clinical measures were consistent with a fairly homogeneous high function cohort (peak oxygen consumption >20 mL/kg/min, robust response to exercise, peak ventilatory efficiency below levels associated with heart failure, MR-derived ejection fraction >50%). Liver evaluation did not reveal clear signs of cirrhosis or extensive fibrosis. However, we observed considerable variability (27-162%) in the increase in stroke index with exercise [100%±64% increase, 53.9±17.4 mL/beat m2 (rest), 101.1±20.7 mL/beat m2, (exercise)]. Computational flow modeling at rest in two patients also showed marked differences in flow distribution and shear stress. We report marked differences in both changes in stroke index during an exercise MRI protocol as well as computational flow patterns at rest suggesting different compensation strategies may be associated with high functioning Fontan patients. The observed heterogeneity illustrates the need for deep phenotyping to capture patient-specific adaptive mechanisms.
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Affiliation(s)
- Francisco Contijoch
- Department of Bioengineering, UC San Diego, La Jolla CA, USA
- Department of Radiology, UC San Diego, La Jolla CA, USA
| | - Bochao Li
- Department of Bioengineering, UC San Diego, La Jolla CA, USA
| | - Weiguang Yang
- Department of Pediatrics, Stanford University, Palo Alto, CA, USA
| | | | - Irine Vodkin
- Department of Medicine, UC San Diego, La Jolla, CA, USA
| | - Beth Printz
- Department of Pediatric Cardiology, Rady Children’s Hospital, San Diego, CA, USA
| | | | - Sanjeet Hegde
- Department of Pediatric Cardiology, Rady Children’s Hospital, San Diego, CA, USA
| | - Alison Marsden
- Department of Pediatrics, Stanford University, Palo Alto, CA, USA
- Department of Bioengineering, Stanford University, Palo Alto, CA, USA
| | - Hannah El-Sabrout
- Department of Society and Genetics, UC Los Angeles, Los Angeles, CA, USA
| | | | - John W. Moore
- Department of Pediatric Cardiology, Rady Children’s Hospital, San Diego, CA, USA
| | - Howaida El-Said
- Department of Pediatric Cardiology, Rady Children’s Hospital, San Diego, CA, USA
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Ono M, Burri M, Mayr B, Anderl L, Cleuziou J, Strbad M, Hager A, Hörer J, Lange R. Flow Dynamics of Bilateral Superior Cavopulomonary Shunts Influence Outcomes After Fontan Completion. Pediatr Cardiol 2020; 41:816-826. [PMID: 32157396 PMCID: PMC7256021 DOI: 10.1007/s00246-020-02318-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2019] [Accepted: 02/13/2020] [Indexed: 11/25/2022]
Abstract
Bilateral superior vena cava (SVC), which occurs following bilateral bidirectional cavopulmonary shunt (BCPS), is an anomaly marked by unique hemodynamics. This study aimed to determine its effects on outcomes after Fontan completion. Among 405 patients who underwent BCPS and total cavopulmonary connection (TCPC) between 1997 and 2017, 40 required a bilateral-BCPS. The dominant SVC prior to TCPC was identified according to the direction of blood flow in the central pulmonary artery, and its relationship to the inferior vena cava (IVC) was classified as a concordant or discordant relationship. Preoperative factors were analyzed to identify the risk factors for specific adverse outcomes. The length of intensive care unit (ICU) stay after TCPC was longer in the 40 patients who underwent bilateral-BCPS than in those who underwent unilateral BCPS (p = 0.024), and the survival rate was lower in the former group than in the latter group (p = 0.004). In the patients who underwent bilateral-BCPS, the dominant SVC was concordant with the IVC in 30 patients and discordant in 10 patients. With regard to whether certain morphological, hemodynamic, and flow dynamics-related variables were risk factors for adverse outcomes following TCPC, a discordant relationship between dominant SVC and IVC was identified as an independent risk factor for both a longer ICU stay (p = 0.037, HR 2.370) and worse survival (p = 0.019, HR 13.880). Therefore, in patients with a bilateral SVC who have previously undergone bilateral-BCPS, a discordant relationship between dominant SVC and IVC might contribute to worse outcomes following TCPC.
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Affiliation(s)
- Masamichi Ono
- Department of Pediatric and Congenital Heart Surgery, German Heart Center Munich, Technische Universität München, Lazarettstraße 36, 80636, Munich, Germany.
| | - Melchior Burri
- Department of Cardiovascular Surgery, German Heart Center Munich, Technische Universität München, Lazarettstraße 36, 80636, Munich, Germany
| | - Benedikt Mayr
- Department of Pediatric and Congenital Heart Surgery, German Heart Center Munich, Technische Universität München, Lazarettstraße 36, 80636, Munich, Germany
- Department of Cardiovascular Surgery, German Heart Center Munich, Technische Universität München, Lazarettstraße 36, 80636, Munich, Germany
| | - Lisa Anderl
- Department of Pediatric and Congenital Heart Surgery, German Heart Center Munich, Technische Universität München, Lazarettstraße 36, 80636, Munich, Germany
| | - Julie Cleuziou
- Department of Pediatric and Congenital Heart Surgery, German Heart Center Munich, Technische Universität München, Lazarettstraße 36, 80636, Munich, Germany
| | - Martina Strbad
- Department of Pediatric and Congenital Heart Surgery, German Heart Center Munich, Technische Universität München, Lazarettstraße 36, 80636, Munich, Germany
| | - Alfred Hager
- Department of Pediatric Cardiology and Congenital Heart Disease, German Heart Center Munich, Technische Universität München, Lazarettstraße 36, 80636, Munich, Germany
| | - Jürgen Hörer
- Department of Pediatric and Congenital Heart Surgery, German Heart Center Munich, Technische Universität München, Lazarettstraße 36, 80636, Munich, Germany
| | - Rüdiger Lange
- Department of Cardiovascular Surgery, German Heart Center Munich, Technische Universität München, Lazarettstraße 36, 80636, Munich, Germany
- German Center for Cardiovascular Research, Munich, Germany
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Telyshev D, Denisov M, Markov A, Fresiello L, Verbelen T, Selishchev S. Energetics of blood flow in Fontan circulation under VAD support. Artif Organs 2019; 44:50-57. [DOI: 10.1111/aor.13564] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 08/21/2019] [Accepted: 08/26/2019] [Indexed: 12/27/2022]
Affiliation(s)
- Dmitry Telyshev
- Institute of Biomedical Systems National Research University of Electronic Technology Zelenograd Russian Federation
- Institute for Bionic Technologies and Engineering I. M. Sechenov First Moscow State Medical University Moscow Russian Federation
| | - Maxim Denisov
- Institute of Biomedical Systems National Research University of Electronic Technology Zelenograd Russian Federation
| | - Aleksandr Markov
- Institute for Bionic Technologies and Engineering I. M. Sechenov First Moscow State Medical University Moscow Russian Federation
| | - Libera Fresiello
- Department of Cardiac Surgery Katholieke Universiteit Leuven Leuven Belgium
| | - Tom Verbelen
- Department of Cardiac Surgery Katholieke Universiteit Leuven Leuven Belgium
| | - Sergey Selishchev
- Institute of Biomedical Systems National Research University of Electronic Technology Zelenograd Russian Federation
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Schwartz SM. Commentary: Why the Y-graft? J Thorac Cardiovasc Surg 2019; 159:665-666. [PMID: 31590958 DOI: 10.1016/j.jtcvs.2019.08.053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 08/06/2019] [Indexed: 11/16/2022]
Affiliation(s)
- Steven M Schwartz
- Divisions of Cardiac Critical Care Medicine and Cardiology, Departments of Paediatrics and Critical Care Medicine, The Hospital for Sick Children and The University of Toronto, Toronto, Ontario, Canada.
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Lee W, Hong Y, Dai G. 3D bioprinting of vascular conduits for pediatric congenital heart repairs. Transl Res 2019; 211:35-45. [PMID: 31034816 PMCID: PMC6702035 DOI: 10.1016/j.trsl.2019.03.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 03/21/2019] [Accepted: 03/24/2019] [Indexed: 12/27/2022]
Abstract
In children with congenital heart defects, surgical correction often involves the use of valves, patches or vascular conduits to establish anatomic continuity. Due to the differences between the pediatric and adult populations, tissue reconstruction in pediatric patients requires a substantially different approach from those in adults. Cardiovascular anatomy of children with congenital heart defect vary, which requires tailored surgical operations for each patient. Since grafts used in these palliative surgeries are sensitive to the local hemodynamic environments, their geometries need to be precisely designed to ensure long-term performance. Tissue engineered vascular grafts (TEVGs) have made tremendous progress over the past decade, but it remains difficult to fabricate patient- and operation-specific vascular grafts. This review summarizes historical milestones of TEVG development for repairing pediatric congenital defects and current clinical outcomes. We also highlight ongoing works on 3D bioprinting of TEVGs with complex geometries and address the current limitations of each technique. Although 3D bioprinted vascular grafts with appropriate functions are yet to be developed, some of the current researches are promising to create better patient specific tissue engineered vascular grafts in the future.
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Affiliation(s)
- Wenhan Lee
- Department of Bioengineering, Northeastern University, Boston, Massachusetts
| | - Yi Hong
- Department of Bioengineering, University of Texas at Arlington, Arlington, Texas
| | - Guohao Dai
- Department of Bioengineering, Northeastern University, Boston, Massachusetts.
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Rodefeld MD, Marsden A, Figliola R, Jonas T, Neary M, Giridharan GA. Cavopulmonary assist: Long-term reversal of the Fontan paradox. J Thorac Cardiovasc Surg 2019; 158:1627-1636. [PMID: 31564543 DOI: 10.1016/j.jtcvs.2019.06.112] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 06/13/2019] [Accepted: 06/14/2019] [Indexed: 01/16/2023]
Abstract
OBJECTIVE Fontan circulatory inefficiency can be addressed by replacing the missing subpulmonary power source to reverse the Fontan paradox. An implantable cavopulmonary assist device is described that will simultaneously reduce systemic venous pressure and increase pulmonary arterial pressure, improving preload and cardiac output, in a univentricular Fontan circulation on a long-term basis. METHODS A rotary blood pump that was based on the von Karman viscous pump was designed for implantation into the total cavopulmonary connection (TCPC). It will impart modest pressure energy to augment Fontan flow without risk of obstruction. In the event of rotational failure, it is designed to default to a passive flow diverter. Pressure-flow performance was characterized in vitro in a Fontan mock circulatory loop with blood analog. RESULTS The pump performed through the fully specified operating range, augmenting flow in all 4 directions of the TCPC. Pressure rise of 6 to 8 mm Hg was readily achieved, ranging to 14 mm Hg at highest speed (5600 rpm). Performance was consistent across a wide range of cardiac outputs. In stalled condition (0 rpm), there was no discernible pressure loss across the TCPC. CONCLUSIONS A blood pump technology is described that can reverse the Fontan paradox and may permit a surgical strategy of long-term biventricular maintenance of a univentricular Fontan circulation. The technology is intended for Fontan failure in which right-sided circulatory inefficiencies predominate and ventricular systolic function is preserved. It may also apply before clinical Fontan failure as health maintenance to preempt the progression of Fontan disease.
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Affiliation(s)
- Mark D Rodefeld
- Section of Cardiothoracic Surgery, Department of Surgery, Indiana University School of Medicine and James Whitcomb Riley Hospital for Children, Indianapolis, Ind.
| | - Alison Marsden
- Department of Bioengineering and Pediatrics, Stanford University, Stanford, Calif
| | - Richard Figliola
- Department of Mechanical Engineering, Clemson University, Clemson, SC
| | | | - Michael Neary
- Rotor Bearing Technology and Software Inc, Phoenixville, Pa
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Trusty PM, Wei Z, Sales M, Kanter KR, Fogel MA, Yoganathan AP, Slesnick TC. Y-graft modification to the Fontan procedure: Increasingly balanced flow over time. J Thorac Cardiovasc Surg 2019; 159:652-661. [PMID: 31399233 DOI: 10.1016/j.jtcvs.2019.06.063] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Revised: 06/03/2019] [Accepted: 06/13/2019] [Indexed: 12/28/2022]
Abstract
OBJECTIVE The use of Y-grafts for Fontan completion is hypothesized to offer more balanced hepatic flow distribution (HFD) and decreased energy losses. The purpose of this study was to evaluate the hemodynamic performance of Y-grafts over time using serial cardiac magnetic resonance data and to compare their performance with extracardiac Fontan connections. METHODS Ten Fontan patients with commercially available Y-graft connections and serial postoperative cardiac magnetic resonance data were included in this study. Patient-specific computational fluid dynamics simulations were used to estimate HFD and energy losses. Y-graft performance was compared with 3 extracardiac conduit Fontan groups (n = 10 for each) whose follow-up times straddle the Y-graft time points. RESULTS Y-graft HFD became significantly more balanced over time (deviation from 50% decreased from 18% ± 14% to 8% ± 8%; P = .015). Total cavopulmonary connection resistance did not significantly change. Y-grafts at 3-year follow-up showed more balanced HFD than the extracardiac conduit groups at both the earlier and later follow-up times. Total cavopulmonary connection resistance was not significantly different between any Y-graft or extracardiac conduit group. CONCLUSIONS Y-grafts showed significantly more balanced HFD over a 3-year follow-up without an increase in total cavopulmonary connection resistance, and therefore may be a valuable option for Fontan completion. Additional follow-up data at longer follow-up times are still needed to thoroughly characterize the potential advantages of Y-graft use.
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Affiliation(s)
- Phillip M Trusty
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Ga
| | - Zhenglun Wei
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Ga
| | - Megan Sales
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Ga
| | - Kirk R Kanter
- Division of Cardiothoracic Surgery, Children's Healthcare of Atlanta, Emory University School of Medicine, Atlanta, Ga
| | - Mark A Fogel
- Division of Cardiology, Children's Hospital of Philadelphia, Philadelphia, Pa
| | - Ajit P Yoganathan
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Ga.
| | - Timothy C Slesnick
- Division of Cardiology, Children's Healthcare of Atlanta, Emory University School of Medicine, Atlanta, Ga
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Affiliation(s)
- Joseph C. Wu
- From the Stanford Cardiovascular Institute (J.C.W., Y.J.W., M.M., R.A.H., T.Q.), Stanford University School of Medicine, CA
- Division of Cardiology (J.C.W., R.A.H., T.Q.), Stanford University School of Medicine, CA
| | - Y. Joseph Woo
- From the Stanford Cardiovascular Institute (J.C.W., Y.J.W., M.M., R.A.H., T.Q.), Stanford University School of Medicine, CA
- Department of Cardiothoracic Surgery (Y.J.W.), Stanford University School of Medicine, CA
| | - Megan Mayerle
- From the Stanford Cardiovascular Institute (J.C.W., Y.J.W., M.M., R.A.H., T.Q.), Stanford University School of Medicine, CA
| | - Robert A. Harrington
- From the Stanford Cardiovascular Institute (J.C.W., Y.J.W., M.M., R.A.H., T.Q.), Stanford University School of Medicine, CA
- Department of Medicine (R.A.H.), Stanford University School of Medicine, CA
- Division of Cardiology (J.C.W., R.A.H., T.Q.), Stanford University School of Medicine, CA
| | - Thomas Quertermous
- From the Stanford Cardiovascular Institute (J.C.W., Y.J.W., M.M., R.A.H., T.Q.), Stanford University School of Medicine, CA
- Division of Cardiology (J.C.W., R.A.H., T.Q.), Stanford University School of Medicine, CA
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41
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Current Challenges and Emergent Technologies for Manufacturing Artificial Right Ventricle to Pulmonary Artery (RV-PA) Cardiac Conduits. Cardiovasc Eng Technol 2019; 10:205-215. [DOI: 10.1007/s13239-019-00406-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 02/05/2019] [Indexed: 01/12/2023]
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Chang SS, Roper M. Microvscular networks with uniform flow. J Theor Biol 2019; 462:48-64. [PMID: 30420333 PMCID: PMC6599712 DOI: 10.1016/j.jtbi.2018.10.049] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2018] [Revised: 10/11/2018] [Accepted: 10/25/2018] [Indexed: 02/03/2023]
Abstract
Within animals, oxygen exchange occurs within vascular transport networks containing potentially billions of microvessels that are distributed throughout the body. By comparison, large blood vessels are theorized to minimize transport costs, leading to tree-like networks that satisfy Murray's law. We know very little about the principles underlying the organization of healthy micro-vascular networks. Indeed capillary networks must also perfuse tissues with oxygen, and efficient perfusion may be incompatible with minimization of transport costs. While networks that minimize transport costs have been well-studied, other optimization principles have received much less scrutiny. In this work we derive the morphology of networks that uniformize blood flow distribution, inspired by the zebrafish trunk micro-vascular network. To find uniform flow networks, we devise a gradient descent algorithm able to optimize arbitrary differentiable objective functions on transport networks, while exactly respecting arbitrary differentiable constraint functions. We prove that in a class of networks that we call stackable, which includes a model capillary bed, the uniform flow network will have the same flow as a uniform conductance network, i.e., in which all edges have the same conductance. This result agrees with uniform flow capillary bed network found by the algorithm. We also show that the uniform flow completely explains the observed radii within the zebrafish trunk vasculature. In addition to deriving new results on optimization of uniform flow in micro-vascular networks, our algorithm provides a general method for testing hypotheses about possible optimization principles underlying real microvascular networks, including exposing tradeoffs between flow uniformity and transport cost.
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Affiliation(s)
- Shyr-Shea Chang
- Department of Mathematics, University of California Los Angeles, Los Angeles, CA 90095, USA.
| | - Marcus Roper
- Department of Mathematics, University of California Los Angeles, Los Angeles, CA 90095, USA; Department of Biomathematics, University of California Los Angeles, Los Angeles, CA 90095, USA
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43
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Gallagher MB, Aycock KI, Craven BA, Manning KB. Steady Flow in a Patient-Averaged Inferior Vena Cava-Part I: Particle Image Velocimetry Measurements at Rest and Exercise Conditions. Cardiovasc Eng Technol 2018; 9:641-653. [PMID: 30411228 PMCID: PMC10508872 DOI: 10.1007/s13239-018-00390-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2018] [Accepted: 10/19/2018] [Indexed: 12/23/2022]
Abstract
PURPOSE Although many previous computational fluid dynamics (CFD) studies have investigated the hemodynamics in the inferior vena cava (IVC), few studies have compared computational predictions to experimental data, and only qualitative comparisons have been made. Herein, we provide particle image velocimetry (PIV) measurements of flow in a patient-averaged IVC geometry under idealized conditions typical of those used in the preclinical evaluation of IVC filters. METHODS Measurements are acquired under rest and exercise flow rate conditions in an optically transparent model fabricated using 3D printing. To ensure that boundary conditions are well-defined and to make follow-on CFD validation studies more convenient, fully-developed flow is provided at the inlets (i.e., the iliac veins) by extending them with straight rigid tubing longer than the estimated entrance lengths. Velocity measurements are then obtained at the downstream end of the tubing to confirm Poiseuille inflow boundary conditions. RESULTS Measurements in the infrarenal IVC reveal that flow profiles are blunter in the sagittal plane (minor axis) than in the coronal plane (major axis). Peak in-plane velocity magnitudes are 4.9 cm/s and 27 cm/s under the rest and exercise conditions, respectively. Flow profiles are less parabolic and exhibit more inflection points at the higher flow rate. Bimodal velocity peaks are also observed in the sagittal plane at the elevated flow condition. CONCLUSIONS The IVC geometry, boundary conditions, and infrarenal velocity measurements are provided for download on a free and publicly accessible repository at https://doi.org/10.6084/m9.figshare.7198703 . These data will facilitate future CFD validation studies of idealized, in vitro IVC hemodynamics and of similar laminar flows in vascular geometries.
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Affiliation(s)
- Maureen B Gallagher
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA, USA
| | - Kenneth I Aycock
- Division of Applied Mechanics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, United States Food and Drug Administration, Silver Spring, MD, USA
| | - Brent A Craven
- Division of Applied Mechanics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, United States Food and Drug Administration, Silver Spring, MD, USA
| | - Keefe B Manning
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA, USA.
- Department of Surgery, Penn State Hershey Medical Center, Hershey, PA, USA.
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Ephrem G, Hebson C, John A, Moore E, Jokhadar M, Ford R, Veldtman G, Dori Y, Gurvitz M, Kogon B, Kovacs A, Roswick M, McConnell M, Book WM, Rodriguez F. Frontiers in Fontan failure: Innovation and improving outcomes: A conference summary. CONGENIT HEART DIS 2018; 14:128-137. [PMID: 30343507 DOI: 10.1111/chd.12685] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 09/14/2018] [Indexed: 12/24/2022]
Abstract
The initial "Frontiers in Fontan Failure" conference in 2015 in Atlanta, GA, provided an opportunity for experts in the field of pediatric cardiology and adult congenital heart disease to focus on the etiology, physiology, and potential interventions for patients with "Failing Fontan" physiology. Four types of "Fontan Failure" were described and then published by Dr Book et al. The acknowledgment that even Dr Fontan himself realized that the Fontan procedure "imposed a gradually declining functional capacity and premature late death after an initial period of often excellent palliation." The purpose of the second "Frontiers in Fontan Failure" was to further the discussion regarding new data and technologies as well as novel interventions. The 2017 "Frontiers in Fontan Failure: Innovation and Improving Outcomes" was sponsored by Children's Healthcare of Atlanta, Sibley Heart Center Cardiology, and Emory University School of Medicine. Future directions in the management of Fontan failure include further investigations into the risk of sudden cardiac death and how to properly prevent it, achievable interventions in modifying the Fontan physiology to treat or prevent late complications, and improved and refined algorithms in Fontan surveillance. Finally, further research into the interventional treatment of lymphatic-related complications hold the promise of marked improvement in the quality of life of advanced Fontan failure patients and as such should be encouraged and contributed to.
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Affiliation(s)
- Georges Ephrem
- Peter Munk Cardiac Centre, University Health Network, Toronto, Canada
| | - Camden Hebson
- Division of Cardiology, Department of Pediatrics, Children's of Alabama, Birmingham, Alabama
| | - Anitha John
- Division of Pediatric Cardiology, Children's National Health System, Washington, District of Columbia
| | - Estella Moore
- Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia
| | - Maan Jokhadar
- Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia
| | - Ryan Ford
- Division of Gastroenterology, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia
| | - Gruschen Veldtman
- Department of Cardiology, The Heart Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Yoav Dori
- Division of Cardiology, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Michelle Gurvitz
- Boston Children's Hospital, Boston, Massachusetts.,Brigham and Women's Hospital, Boston, Massachusetts
| | - Brian Kogon
- Division of Pediatric Cardiothoracic Surgery, University of Mississippi Medical Center, Jackson, Mississippi
| | - Adrienne Kovacs
- Knight Cardiovascular Institute, Oregon Health & Science University, Portland, Oregon
| | | | - Michael McConnell
- Sibley Heart Center Cardiology, Emory University School of Medicine, Atlanta, Georgia
| | - Wendy M Book
- Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia
| | - Fred Rodriguez
- Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia.,Sibley Heart Center Cardiology, Emory University School of Medicine, Atlanta, Georgia
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Owen B, Bojdo N, Jivkov A, Keavney B, Revell A. Structural modelling of the cardiovascular system. Biomech Model Mechanobiol 2018; 17:1217-1242. [PMID: 29911296 PMCID: PMC6154127 DOI: 10.1007/s10237-018-1024-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 04/25/2018] [Indexed: 02/02/2023]
Abstract
Computational modelling of the cardiovascular system offers much promise, but represents a truly interdisciplinary challenge, requiring knowledge of physiology, mechanics of materials, fluid dynamics and biochemistry. This paper aims to provide a summary of the recent advances in cardiovascular structural modelling, including the numerical methods, main constitutive models and modelling procedures developed to represent cardiovascular structures and pathologies across a broad range of length and timescales; serving as an accessible point of reference to newcomers to the field. The class of so-called hyperelastic materials provides the theoretical foundation for the modelling of how these materials deform under load, and so an overview of these models is provided; comparing classical to application-specific phenomenological models. The physiology is split into components and pathologies of the cardiovascular system and linked back to constitutive modelling developments, identifying current state of the art in modelling procedures from both clinical and engineering sources. Models which have originally been derived for one application and scale are shown to be used for an increasing range and for similar applications. The trend for such approaches is discussed in the context of increasing availability of high performance computing resources, where in some cases computer hardware can impact the choice of modelling approach used.
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Affiliation(s)
- Benjamin Owen
- School of Mechanical, Aerospace and Civil Engineering, University of Manchester, George Begg Building, Manchester, M1 3BB, UK.
| | - Nicholas Bojdo
- School of Mechanical, Aerospace and Civil Engineering, University of Manchester, George Begg Building, Manchester, M1 3BB, UK
| | - Andrey Jivkov
- School of Mechanical, Aerospace and Civil Engineering, University of Manchester, George Begg Building, Manchester, M1 3BB, UK
| | - Bernard Keavney
- Division of Cardiovascular Sciences, University of Manchester, AV Hill Building, Manchester, M13 9PT, UK
| | - Alistair Revell
- School of Mechanical, Aerospace and Civil Engineering, University of Manchester, George Begg Building, Manchester, M1 3BB, UK
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Rijnberg FM, Hazekamp MG, Wentzel JJ, de Koning PJ, Westenberg JJ, Jongbloed MR, Blom NA, Roest AA. Energetics of Blood Flow in Cardiovascular Disease. Circulation 2018; 137:2393-2407. [DOI: 10.1161/circulationaha.117.033359] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
| | | | - Jolanda J. Wentzel
- Leiden University Medical Center, The Netherlands. Department of Biomechanical Engineering, Erasmus Medical Center, Rotterdam, The Netherlands (J.J.W.)
| | | | | | | | - Nico A. Blom
- Department of Pediatric Cardiology (N.A.B., A.A.W.R.)
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Dhayananth K, Narasimhan A. Evaluation of hemodynamic performance of total cavopulmonary connection (TCPC) with porous inserts. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2018; 34:e2937. [PMID: 29116689 DOI: 10.1002/cnm.2937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Revised: 09/29/2017] [Accepted: 10/24/2017] [Indexed: 06/07/2023]
Abstract
Infants born with univentricular heart disease undergo Fontan surgery to establish separate systemic and pulmonary circulations. This surgery results in better blood circulation across a single ventricle that supplies oxygenated blood to the body and passively returns venous blood to the lungs through the total cavopulmonary connection (TCPC). Reducing the pressure drop across the TCPC during Fontan circulation helps in reducing the work load of univentricular heart, and various designs have been proposed for this purpose. The goal of this work is to analyze the effect of placing a porous insert at an appropriate position in the pulmonary artery, on the pressure drop across the TCPC. A 3D computational model of a total TCPC connection provided with a porous insert is developed and solved by finite volume method, under assumptions of steady, laminar, and Newtonian flows. The effects of the porous medium properties-porosity and permeability-across the connection, are analyzed. Compared to the no-porous medium case, TCPC with the porous medium insert exhibits a maximum reduction of 27% in energy loss for the flow range studied. The porous medium used in TCPC connection lowers the energy dissipation by curtailing the flow recirculation zones across the connection. The influences of the diameter of the blood vessel, total cardiac output, and the thickness, permeability, and position of porous media on energy loss are analyzed. The criteria to select the porous medium properties and position for a given Fontan geometry are also determined.
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Affiliation(s)
- K Dhayananth
- Heat Transfer and Thermal Power Laboratory, Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai, 600036, Tamil Nadu, India
| | - Arunn Narasimhan
- Heat Transfer and Thermal Power Laboratory, Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai, 600036, Tamil Nadu, India
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Xu F, Morganti S, Zakerzadeh R, Kamensky D, Auricchio F, Reali A, Hughes TJ, Sacks MS, Hsu MC. A framework for designing patient-specific bioprosthetic heart valves using immersogeometric fluid-structure interaction analysis. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2018; 34:e2938. [PMID: 29119728 PMCID: PMC5893448 DOI: 10.1002/cnm.2938] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 09/08/2017] [Accepted: 10/22/2017] [Indexed: 05/07/2023]
Abstract
Numerous studies have suggested that medical image derived computational mechanics models could be developed to reduce mortality and morbidity due to cardiovascular diseases by allowing for patient-specific surgical planning and customized medical device design. In this work, we present a novel framework for designing prosthetic heart valves using a parametric design platform and immersogeometric fluid-structure interaction (FSI) analysis. We parameterize the leaflet geometry using several key design parameters. This allows for generating various perturbations of the leaflet design for the patient-specific aortic root reconstructed from the medical image data. Each design is analyzed using our hybrid arbitrary Lagrangian-Eulerian/immersogeometric FSI methodology, which allows us to efficiently simulate the coupling of the deforming aortic root, the parametrically designed prosthetic valves, and the surrounding blood flow under physiological conditions. A parametric study is performed to investigate the influence of the geometry on heart valve performance, indicated by the effective orifice area and the coaptation area. Finally, the FSI simulation result of a design that balances effective orifice area and coaptation area reasonably well is compared with patient-specific phase contrast magnetic resonance imaging data to demonstrate the qualitative similarity of the flow patterns in the ascending aorta.
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Affiliation(s)
- Fei Xu
- Department of Mechanical Engineering, Iowa State University, 2025 Black Engineering, Ames, IA 50011, USA
| | - Simone Morganti
- Department of Electrical, Computer, and Biomedical Engineering, University of Pavia, via Ferrata 3, 27100, Pavia Italy
| | - Rana Zakerzadeh
- Center for Cardiovascular Simulation, Institute for Computational Engineering and Sciences, The University of Texas at Austin, 201 East 24th St, Stop C0200, Austin, TX 78712, USA
| | - David Kamensky
- Department of Structural Engineering, University of California, San Diego, 9500 Gilman Drive, Mail Code 0085 La Jolla, CA 92093, USA
| | - Ferdinando Auricchio
- Department of Civil Engineering and Architecture, University of Pavia, via Ferrata 3, 27100, Pavia, Italy
| | - Alessandro Reali
- Department of Civil Engineering and Architecture, University of Pavia, via Ferrata 3, 27100, Pavia, Italy
| | - Thomas J.R. Hughes
- Center for Cardiovascular Simulation, Institute for Computational Engineering and Sciences, The University of Texas at Austin, 201 East 24th St, Stop C0200, Austin, TX 78712, USA
| | - Michael S. Sacks
- Center for Cardiovascular Simulation, Institute for Computational Engineering and Sciences, The University of Texas at Austin, 201 East 24th St, Stop C0200, Austin, TX 78712, USA
| | - Ming-Chen Hsu
- Department of Mechanical Engineering, Iowa State University, 2025 Black Engineering, Ames, IA 50011, USA
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Trusty PM, Slesnick TC, Wei ZA, Rossignac J, Kanter KR, Fogel MA, Yoganathan AP. Fontan Surgical Planning: Previous Accomplishments, Current Challenges, and Future Directions. J Cardiovasc Transl Res 2018; 11:133-144. [PMID: 29340873 PMCID: PMC5910220 DOI: 10.1007/s12265-018-9786-0] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Accepted: 01/05/2018] [Indexed: 11/29/2022]
Abstract
The ultimate goal of Fontan surgical planning is to provide additional insights into the clinical decision-making process. In its current state, surgical planning offers an accurate hemodynamic assessment of the pre-operative condition, provides anatomical constraints for potential surgical options, and produces decent post-operative predictions if boundary conditions are similar enough between the pre-operative and post-operative states. Moving forward, validation with post-operative data is a necessary step in order to assess the accuracy of surgical planning and determine which methodological improvements are needed. Future efforts to automate the surgical planning process will reduce the individual expertise needed and encourage use in the clinic by clinicians. As post-operative physiologic predictions improve, Fontan surgical planning will become an more effective tool to accurately model patient-specific hemodynamics.
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Affiliation(s)
- Phillip M Trusty
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
| | - Timothy C Slesnick
- Department of Pediatrics, Division of Cardiology, Children's Healthcare of Atlanta, Emory University School of Medicine, Atlanta, GA, USA
| | - Zhenglun Alan Wei
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
- School of Life Science, Fudan University, Shanghai, China
| | - Jarek Rossignac
- School of Interactive Computing, Georgia Institute of Technology, Atlanta, GA, USA
| | - Kirk R Kanter
- Division of Cardiothoracic Surgery, Children's Healthcare of Atlanta, Emory University School of Medicine, Atlanta, GA, USA
| | - Mark A Fogel
- Division of Cardiology, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Ajit P Yoganathan
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA.
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Talwar S, Sankhyan L, Patel C, Sreenivas V, Choudhary SK, Airan B. Evaluation of differential pulmonary perfusion using 99mTc macroaggregated albumin after the Fontan procedure. Interact Cardiovasc Thorac Surg 2018; 26:651-659. [PMID: 29240900 DOI: 10.1093/icvts/ivx377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Accepted: 10/30/2017] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVES The Fontan procedure [total cavopulmonary connection (TCPC)] is the final palliation for patients with univentricular physiology. We studied differential perfusion ratio and percentage uptake of a radiotracer in different zones of each lung following TCPC. METHODS Between July 2015 and June 2017, 45 patients underwent 99mTc macroaggregated albumin lung perfusion scan at a mean follow-up period of 49.3 ± SD 26.1 days following TCPC. Differential perfusion ratio and percentage uptake of the radiotracer in the upper, middle and lower zones of each lung were calculated. RESULTS Post-foot injection [inferior vena cava (IVC) injection], preferential flow to the lungs was as follows: left lung (n = 13, 30.2%), right lung (n = 13, 30.2%) and uniformly to both lungs (n= 17, 39.6%). Post-arm injection [superior vena cava (SVC) injection], preferential flow to the lungs was as follows: left lung (n = 13, 30.2%), right lung (n = 22, 51.2%) and uniformly to both lungs (n= 8, 18.6%). The middle zone was perfused the most in both lungs. Total lower zone mean perfusion was higher than the upper zone following both SVC injection and IVC injection (34.1 ± SD 5.3% vs 17. ± SD 4.1% and 33 ± SD 5.0% vs 17.5 ± SD 4.1%, respectively). In patients with bilateral SVC, post-IVC injection, 6 (75%) patients had preferential flow to the right lung, whereas post-SVC injection, preferential flow to the left lung was visualized in 7 (87.5%) patients. CONCLUSIONS Following TCPC, IVC blood was distributed uniformly in both lungs. SVC blood preferentially perfused the right lung. The middle zone was perfused the most in both lungs.
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Affiliation(s)
- Sachin Talwar
- Department of Cardiothoracic and Vascular Surgery, Cardiothoracic Center, All India Institute of Medical Sciences, New Delhi, India
| | - Lakshmi Sankhyan
- Department of Cardiothoracic and Vascular Surgery, Cardiothoracic Center, All India Institute of Medical Sciences, New Delhi, India
| | - Chetan Patel
- Nuclear Medicine, All India Institute of Medical Sciences, New Delhi, India
| | | | - Shiv Kumar Choudhary
- Department of Cardiothoracic and Vascular Surgery, Cardiothoracic Center, All India Institute of Medical Sciences, New Delhi, India
| | - Balram Airan
- Department of Cardiothoracic and Vascular Surgery, Cardiothoracic Center, All India Institute of Medical Sciences, New Delhi, India
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