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Pedersen DD, Kim S, D'Amore A, Wagner WR. Influence of Polymer Stiffness and Geometric Design on Fluid Mechanics in Tissue-Engineered Pulmonary Valve Scaffolds. Ann Biomed Eng 2024; 52:575-587. [PMID: 37935910 DOI: 10.1007/s10439-023-03401-z] [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: 08/11/2023] [Accepted: 10/29/2023] [Indexed: 11/09/2023]
Abstract
There is still much unknown about the fluid mechanical response to cardiac valve scaffolds, even as their implementation in the clinic is on the horizon. Specifically, while degradable polymer valve scaffolds are currently being tested in the pulmonary valve position, their material and mechanical properties have not been fully elucidated. Optimizing these properties are important determinants not only of acute function, but long-term remodeling prospects. This study aimed to characterize fluid profiles downstream of electrospun valve scaffolds under dynamic pulmonary conditions. Valve scaffold design was changed by either blending poly(carbonate urethane) urea (PCUU) with poly(ε-caprolactone) (PCL) to modulate material stiffness or by changing the geometric design of the valve scaffolds. Specifically, two designs were utilized: one modeled after a clinically used bioprosthetic valve design (termed Mk1 design), and another using a geometrically "optimized" design (termed Mk2) based on anatomical data. Particle image velocimetry results showed that material stiffness only had a mild impact on fluid mechanics, measured by velocity magnitude, vorticity, viscous shear stress, Reynolds shear stress, and turbulent kinetic energy. However, comparing the two geometric designs yielded a much greater impact, with the Mk2 valve groups containing the highest PCUU/PCL ratio demonstrating the overall best performance. This report highlights the easily manipulable design features of polymeric valve scaffolds and demonstrates their relative significance for valve function.
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Affiliation(s)
- Drake D Pedersen
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Seungil Kim
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
- Department of Surgery, University of Pittsburgh, Pittsburgh, PA, USA
| | - Antonio D'Amore
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
- Department of Surgery, University of Pittsburgh, Pittsburgh, PA, USA
- Fondazione Ri.MED, Palermo, Italy
- Clinical and Translational Science Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - William R Wagner
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA.
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA.
- Department of Surgery, University of Pittsburgh, Pittsburgh, PA, USA.
- Department of Chemical Engineering, University of Pittsburgh, Pittsburgh, PA, USA.
- Clinical and Translational Science Institute, University of Pittsburgh, Pittsburgh, PA, USA.
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2
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Ponnaluri SV, Sacks MS, Manning KB. The Accelerated Transcatheter Heart Valve Testing Environment: Loading, Motion, and Fluid Dynamics. J Biomech Eng 2023; 145:031005. [PMID: 36416296 PMCID: PMC9791666 DOI: 10.1115/1.4056291] [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: 07/24/2022] [Revised: 11/15/2022] [Accepted: 11/16/2022] [Indexed: 11/24/2022]
Abstract
Transcatheter aortic valve replacements (TAVRs) are an increasingly common treatment for aortic valve disease due to their minimally invasive delivery. As TAVR designs require thinner leaflets to facilitate catheter-based delivery, they experience greater leaflet operational stresses and potentially greater durability issues than conventional surgical valves. Yet, our understanding of TAVR durability remains largely unexplored. Currently, preclinical TAVR durability is evaluated within an ISO:5840 compliant accelerated wear tester (AWT) up to a required 200 × 106 cycles, corresponding to approximately five years in vivo. While AWTs use high cycle frequencies (10-20 Hz) to achieve realistic timeframes, the resulting valve loading behaviors and fluid dynamics are not representative of the in vivo environment and thus may not accurately predict failure mechanisms. Despite the importance of fatigue and failure predictions for replacement heart valves, surprisingly, little quantitative information exists on the dynamic AWT environment. To better understand this environment, we examined frequency and diastolic period effects for the first time using high-speed enface imaging and particle image velocimetry to quantify valve motion and flow, respectively, using a Durapulse™ AWT at frequencies of 10, 15, and 20 Hz. Regardless of operating condition, no waveform achieved a physiologically relevant transvalvular loading pressure, despite having an ISO compliant geometric orifice area (GOA) and waveform. General fluid mechanics were consistent with in vivo but the AWT geometry developed secondary flow structures, which could impact mechanical loading. Therefore, the nonphysiologic loading and variability induced by changes in operating condition must be carefully regulated to ensure physiologically relevant fatigue.
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Affiliation(s)
- Sailahari V. Ponnaluri
- Department of Biomedical Engineering, The Pennsylvania State University, 122 Chemical and Biomedical Engineering Building, University Park, PA 16802
| | - Michael S. Sacks
- James T. Willerson Center for Cardiovascular Modeling and Simulation, Oden Institute for Computational Engineering Sciences, University of Texas, Austin, TX 78712; Department of Biomedical Engineering, University of Texas, Austin, TX 78712
| | - Keefe B. Manning
- Department of Biomedical Engineering, The Pennsylvania State University, 122 Chemical and Biomedical Engineering Building, University Park, PA 16802; Department of Surgery, Penn State Hershey Medical Center, Hershey, PA 17033
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3
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Qiu D, Azadani AN. Structural analysis of regional transcatheter aortic valve underexpansion and its implications for subclinical leaflet thrombosis. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2022; 38:e3641. [PMID: 36054800 DOI: 10.1002/cnm.3641] [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: 02/09/2022] [Revised: 05/31/2022] [Accepted: 08/13/2022] [Indexed: 06/15/2023]
Abstract
Subclinical leaflet thrombosis has been increasingly recognized following transcatheter aortic valve replacement (TAVR). Determining the risk factors is vital in preventing clinical leaflet thrombosis and ensuring long-term value durability. Clinical data have indicated that regional stent under-expansion of transcatheter aortic valves (TAVs), particularly self-expanding devices, may be associated with an increased risk of subclinical leaflet thrombosis. This study aimed to determine the effects of regional TAV frame under-expansion on leaflet kinematics, leaflet structural characteristics, and explore its impact on the likelihood of leaflet thrombosis. In this study, mild and moderate regional frame under-expansion of a 26-mm CoreValve were examined using experimental testing and computational simulations. The results indicated that regional TAV frame under-expansion impairs leaflet kinematics and reduces the range of motion in leaflets with an angle less than 120°. The reduced range of motion can increase blood stasis on the surface of the TAV leaflets. The results also demonstrated that regional frame under-expansion induced localized high-stress regions in the leaflets close to the fixed boundary edge. The increased mechanical stress can lead to accelerated tissue degeneration. The study improves our understanding of the effects of regional stent under-expansion in TAVR. Post-procedural balloon dilatation of self-expanding TAVs can potentially be advantageous in reducing leaflet distortion and normalizing leaflet stress distribution. Large-scale, prospective, and well-controlled studies are needed to further investigate regional TAV frame under-expansion effects on subclinical leaflet thrombosis and long-term valve durability.
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Affiliation(s)
- Dong Qiu
- The DU Cardiovascular Biomechanics Laboratory, Department of Mechanical and Materials Engineering, University of Denver, Denver, Colorado, USA
| | - Ali N Azadani
- The DU Cardiovascular Biomechanics Laboratory, Department of Mechanical and Materials Engineering, University of Denver, Denver, Colorado, USA
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4
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Vogl BJ, El Shaer A, Crestanello JA, Alkhouli M, Hatoum H. Flow dynamics in the sinus and downstream of third and fourth generation balloon expandable transcatheter aortic valves. J Mech Behav Biomed Mater 2022; 127:105092. [DOI: 10.1016/j.jmbbm.2022.105092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 12/27/2021] [Accepted: 01/12/2022] [Indexed: 10/19/2022]
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Qiu D, Barakat M, Hopkins B, Ravaghi S, Azadani AN. Transcatheter aortic valve replacement in bicuspid valves: The synergistic effects of eccentric and incomplete stent deployment. J Mech Behav Biomed Mater 2021; 121:104621. [PMID: 34130079 DOI: 10.1016/j.jmbbm.2021.104621] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 04/19/2021] [Accepted: 05/28/2021] [Indexed: 10/21/2022]
Abstract
Bicuspid aortic valve is a congenital cardiac anomaly and common etiology of aortic stenosis. Given the positive outcomes of transcatheter aortic valve replacement (TAVR) in low-risk patients, TAVR will become more prevalent in the future in the treatment of severe bicuspid valve stenosis. However, asymmetrical bicuspid valve anatomy and calcification can prevent the circular and complete expansion of transcatheter aortic valves (TAVs). In previous studies, examining the impact of elliptical TAV deployment on leaflet stress distribution, asymmetric expansion of balloon-expandable intra-annular devices was studied up to an ellipticity index (long/short TAV diameter) of 1.4. However, such a high degree of eccentricity has not been observed in clinical studies with balloon-expandable devices. High degrees of stent eccentricity have been observed in self-expanding TAVs, such as CoreValve. However, CoreValve is a supra-annular device, and it was not clear if eccentric and incomplete stent deployment at the annulus would alter leaflet stress and strain distributions. This study aimed to assess the effects of eccentric and incomplete stent deployment of CoreValves in bicuspid aortic valves and compare the results to that of SAPIEN 3. Leaflet stress distribution and leaflet kinematics of 26-mm CoreValve and 26-mm SAPIEN 3 devices in bicuspid valves were obtained in a range that was observed in previous clinical studies. The results indicated that elliptical and incomplete stent deployment of TAVs increase leaflet stress and impair leaflet kinematics. The changes were more pronounced in CoreValve than SAPIEN 3. Increased leaflet stress can reduce long-term valve durability, and impaired leaflet kinematics can potentially increase blood stasis on the TAV leaflets. The study provides complementary insights into the mechanics of TAVs in bicuspid aortic valves.
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Affiliation(s)
- Dong Qiu
- Department of Mechanical and Materials Engineering, University of Denver, Denver, CO, USA
| | - Mohammed Barakat
- Department of Mechanical and Materials Engineering, University of Denver, Denver, CO, USA
| | - Brenna Hopkins
- Department of Mechanical and Materials Engineering, University of Denver, Denver, CO, USA
| | - Saba Ravaghi
- Department of Mechanical and Materials Engineering, University of Denver, Denver, CO, USA
| | - Ali N Azadani
- Department of Mechanical and Materials Engineering, University of Denver, Denver, CO, USA.
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6
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Transcatheter Heart Valve Downstream Fluid Dynamics in an Accelerated Evaluation Environment. Ann Biomed Eng 2021; 49:2170-2182. [PMID: 33638029 DOI: 10.1007/s10439-021-02751-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 02/12/2021] [Indexed: 10/22/2022]
Abstract
Transcatheter aortic valve replacements (TAVRs) provide minimally invasive delivery of bioprosthetic heart valves (BHVs) for the treatment of aortic valve disease. While surgical BHVs show efficacy for 8-10 years, long-term TAVR durability remains unknown. Pre-clinical testing evaluates BHV durability in an ISO:5840 compliant accelerated wear tester (AWT), yet, the design and development of AWTs and their accuracy in predicting in vivo performance, is unclear. As a result of limited knowledge on AWT environment and BHV loading, durability assessment of candidate valves remains fundamentally empirical. For the first time, high-speed particle image velocimetry quantified an ISO:5840 compliant downstream AWT velocity field, Reynolds stresses, and turbulence intensity. TAVR enface imaging quantified the orifice area and estimated the flow rate. When valve area and flow rate were at their maximum during peak systole (1.49 cm2 and 16.05 L/min, respectively), central jet velocity, Reynolds normal and shear stress, and turbulence intensity grew to 0.50 m/s, 265.1 Pa, 124.6 Pa, and 37.3%, respectively. During diastole, unique AWT recirculation produced retrograde flow and the directional changes created eddies. These novel AWT findings demonstrated a substantially reduced valve fully loaded period and pressure not matching in vivo or in vitro studies, despite the comparable fluid environment and TAVR motion.
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Pott D, Sedaghat A, Schmitz C, Werner N, Schmitz-Rode T, Steinseifer U, Jansen SV. Hemodynamics inside the neo- and native sinus after TAVR: Effects of implant depth and cardiac output on flow field and coronary flow. Artif Organs 2020; 45:68-78. [PMID: 32750157 DOI: 10.1111/aor.13789] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 06/19/2020] [Accepted: 07/20/2020] [Indexed: 12/22/2022]
Abstract
Transcatheter aortic valve replacement (TAVR) has emerged as a widely used therapy for aortic valve diseases. With TAVR, flow hemodynamics may change leading to areas of flow stagnation prone to thrombosis risk. The neo-sinus, created by introducing a prosthesis inside the diseased native valve, may prompt leaflet thrombosis due to areas of flow stasis. This study attempted to understand the effect of different prosthesis implant depths on the flow field within the neo- and native sinus and on the coronary perfusion. Experiments were performed inside an in vitro pulse duplicator producing physiological conditions according to ISO 5840-1:2015 standard. Flow fields were obtained for two cardiac outputs (CO) using particle image velocimetry (PIV). Washout was calculated as a measure of flow stasis. The two main results are: a lower implant position and a lower CO/frequency led to better native sinus washout, but worsened neo-sinus washout. In contrast, a higher implant position led to higher coronary flow (for higher CO/frequency). No significant effect of implant depth on coronary flow was observed for lower CO/frequency. In summary, a higher implant position using this self-expanding prosthesis is associated with reduced neo-sinus flow stasis. Hereby, washout of the native sinus, as well as coronary flow, are dependent on cardiac output.
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Affiliation(s)
- Desiree Pott
- Department of Cardiovascular Engineering, Institute of Applied Medical Engineering, Helmholtz Institute, Medical Faculty, RWTH Aachen University, Aachen, Germany
| | | | - Christoph Schmitz
- Department of Cardiovascular Engineering, Institute of Applied Medical Engineering, Helmholtz Institute, Medical Faculty, RWTH Aachen University, Aachen, Germany
| | - Nikos Werner
- Innere Medizin III/Kardiologie, Krankenhaus der Barmherzigen Brüder Trier, Trier, Germany
| | - Thomas Schmitz-Rode
- Institute of Applied Medical Engineering, Helmholtz Institute, Medical Faculty, RWTH Aachen University, Aachen, Germany
| | - Ulrich Steinseifer
- Department of Cardiovascular Engineering, Institute of Applied Medical Engineering, Helmholtz Institute, Medical Faculty, RWTH Aachen University, Aachen, Germany
| | - Sebastian Victor Jansen
- Department of Cardiovascular Engineering, Institute of Applied Medical Engineering, Helmholtz Institute, Medical Faculty, RWTH Aachen University, Aachen, Germany
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Nappi F, Nenna A, Sing SSA, Timofeeva I, Mihos C, Gentile F, Chello M. Are the dynamic changes of the aortic root determinant for thrombosis or leaflet degeneration after transcatheter aortic valve replacement? J Thorac Dis 2020; 12:2919-2925. [PMID: 32642204 PMCID: PMC7330384 DOI: 10.21037/jtd.2020.02.01] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The role of the aortic root is to convert the accumulated elastic energy during systole into kinetic flow energy during diastole, in order to improve blood distribution in the coronary tree. Therefore, the sinuses of Valsalva of the aortic root are not predisposed to accept any bulky material, especially in case of uncrushed solid calcific agglomerates. This concept underlines the differences between surgical aortic valve replacement, in which decalcification is a main part of the procedure, and transcatheter aortic valve replacement (TAVR). Cyclic changes in shape and size of the aortic root influence blood flow in the Valsalva sinuses. Recent papers have been investigating the dynamic changes of the aortic root and whether those differences might be correlated with clinical effects, and this paper aims to summarize part of this flourishing literature. Post-TAVR aortic root remodeling, dynamic flow and TAVR complications might have a fluidodynamic background, and clinically observed side effects such as thrombosis or leaflet degeneration should be further investigated in basic researches. Also, aortic root changes could impact valve type and size selection, affecting the decision of over-sizing or under-sizing in order to prevent valve embolization or coronary ostia obstruction.
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Affiliation(s)
- Francesco Nappi
- Department of Cardiac Surgery, Centre Cardiologique du Nord de Saint-Denis, Paris, France
| | - Antonio Nenna
- Department of Cardiovascular Surgery, Università Campus Bio-Medico di Roma, Rome, Italy
| | - Sanjeet Singh Avvtar Sing
- Department of Cardiac Surgery, Golden Jubilee National Hospital, Glasgow, UK.,Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, UK
| | - Irina Timofeeva
- Department of Imaging, Centre Cardiologique du Nord de Saint-Denis, Paris, France
| | - Christos Mihos
- Echocardiography Lab, Columbia University Division of Cardiology, Mount Sinai Heart Institute, Miami, USA
| | | | - Massimo Chello
- Department of Cardiovascular Surgery, Università Campus Bio-Medico di Roma, Rome, Italy
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Khodaee F, Barakat M, Abbasi M, Dvir D, Azadani AN. Incomplete expansion of transcatheter aortic valves is associated with propensity for valve thrombosis. Interact Cardiovasc Thorac Surg 2019; 30:39-46. [DOI: 10.1093/icvts/ivz213] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 06/24/2019] [Accepted: 08/04/2019] [Indexed: 11/14/2022] Open
Abstract
Abstract
OBJECTIVES
Clinical and subclinical leaflet thromboses are increasingly recognized complications following transcatheter aortic valve replacement. Identification of the risk factors is important to mitigate the occurrence of leaflet thrombosis in transcatheter aortic valves (TAVs) and ensure their long-term function. The goal of this study was to determine the effect of incomplete expansion of TAVs on the likelihood of leaflet thrombosis following transcatheter aortic valve replacement.
METHODS
Using experimental and computational methods, 3-dimensional unsteady flow fields of 26-mm SAPIEN 3 valves expanded to 3 different diameters (i.e. 26.0 mm, 23.4 mm and 20.8 mm) were determined in patient-specific geometries. The diameters corresponded to 100%, 90% and 80% stent expansion, respectively. To address the potential difference in the likelihood of leaflet thrombosis, blood residence time (i.e. stasis) and viscous shear stress on the surface of TAV leaflets were quantified and compared.
RESULTS
The results indicated that TAV underexpansion increased blood stasis on the TAV leaflets. Blood residence time on the surface of the leaflets after 80% and 90% TAV expansion on average was 9.4% and 4.1% more than that of the fully expanded TAV, respectively. In addition, areas of blood stasis time of more than 0.5 s, which are highly prone to platelet activation, increased linearly as the degree of TAV underexpansion increased.
CONCLUSIONS
Incomplete expansion of TAVs increases blood stasis on the surface of TAV leaflets. Regions of blood stasis promote platelet activation and thrombotic events. TAV underexpansion can therefore increase the risk of leaflet thrombosis in patients with transcatheter aortic valve replacement.
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Affiliation(s)
- Farhan Khodaee
- The DU Cardiovascular Biomechanics Laboratory, Department of Mechanical and Materials Engineering, University of Denver, Denver, CO, USA
| | - Mohammed Barakat
- The DU Cardiovascular Biomechanics Laboratory, Department of Mechanical and Materials Engineering, University of Denver, Denver, CO, USA
| | - Mostafa Abbasi
- The DU Cardiovascular Biomechanics Laboratory, Department of Mechanical and Materials Engineering, University of Denver, Denver, CO, USA
| | - Danny Dvir
- Division of Cardiology, Department of Medicine, University of Washington, Seattle, WA, USA
| | - Ali N Azadani
- The DU Cardiovascular Biomechanics Laboratory, Department of Mechanical and Materials Engineering, University of Denver, Denver, CO, USA
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Malchesky PS. Artificial Organs 2018: A Year in Review. Artif Organs 2019; 43:288-317. [PMID: 30680758 DOI: 10.1111/aor.13428] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Accepted: 01/22/2019] [Indexed: 12/24/2022]
Abstract
In this Editor's Review, articles published in 2018 are organized by category and summarized. We provide a brief reflection of the research and progress in artificial organs intended to advance and better human life while providing insight for continued application of these technologies and methods. Artificial Organs continues in the original mission of its founders "to foster communications in the field of artificial organs on an international level." Artificial Organs continues to publish developments and clinical applications of artificial organ technologies in this broad and expanding field of organ Replacement, Recovery, and Regeneration from all over the world. Peer-reviewed special issues this year included contributions from the 13th International Conference on Pediatric Mechanical Circulatory Support Systems and Pediatric Cardiopulmonary Perfusion edited by Dr. Akif Undar, and the 25th Congress of the International Society for Mechanical Circulatory Support edited by Dr. Marvin Slepian. Additionally, many editorials highlighted the worldwide survival differences in hemodialysis and perspectives on mechanical circulatory support and stem cell therapies for cardiac support. We take this time also to express our gratitude to our authors for offering their work to this journal. We offer our very special thanks to our reviewers who give so generously of time and expertise to review, critique, and especially provide meaningful suggestions to the author's work whether eventually accepted or rejected. Without these excellent and dedicated reviewers the quality expected from such a journal could not be possible. We also express our special thanks to our Publisher, John Wiley & Sons for their expert attention and support in the production and marketing of Artificial Organs. We look forward to reporting further advances in the coming years.
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A Non-Invasive Material Characterization Framework for Bioprosthetic Heart Valves. Ann Biomed Eng 2018; 47:97-112. [PMID: 30229500 DOI: 10.1007/s10439-018-02129-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 09/11/2018] [Indexed: 10/28/2022]
Abstract
Computational modeling and simulation has become more common in design and development of bioprosthetic heart valves. To have a reliable computational model, considering accurate mechanical properties of biological soft tissue is one of the most important steps. The goal of this study was to present a non-invasive material characterization framework to determine mechanical propertied of soft tissue employed in bioprosthetic heart valves. Using integrated experimental methods (i.e., digital image correlation measurements and hemodynamic testing in a pulse duplicator system) and numerical methods (i.e., finite element modeling and optimization), three-dimensional anisotropic mechanical properties of leaflets used in two commercially available transcatheter aortic valves (i.e., Edwards SAPIEN 3 and Medtronic CoreValve) were characterized and compared to that of a commonly used and well-examined surgical bioprosthesis (i.e., Carpentier-Edwards PERIMOUNT Magna aortic heart valve). The results of the simulations showed that the highest stress value during one cardiac cycle was at the peak of systole in the three bioprostheses. In addition, in the diastole, the peak of maximum in-plane principal stress was 0.98, 0.96, and 2.95 MPa for the PERIMOUNT Magna, CoreValve, and SAPIEN 3, respectively. Considering leaflet stress distributions, there might be a difference in the long-term durability of different TAV models.
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