Aortic stenosis is the most common valvular heart disease in the Western world and its prevalence is growing with an aging population. The current preferred method of treatment is complete valve replacement with a surgically implanted prosthetic valve. However, for high-risk patients with advanced age and co- morbidities, operative mortality escalates. Recently, minimally invasive transcatheter aortic valve (TAV) implantation has been investigated as an endovascular alternative to surgical valve replacement. Although significant experience has been gained, TAV implantation clinical trials have been associated with complications such as device migration, paravalvular leakage, coronary obstruction, and access site injury. Furthermore, the long-term durability and safety of TAV prostheses are largely unknown and must be evaluated and studied carefully. To gain a quantitative understanding of the biomechanics involved in TAV intervention, our objectives in this project are to develop probabilistic computational models to investigate aortic tissue-TAV structural interaction and hemodynamics under a variety of patient conditions, and to offer scientific rationale for TAV patient screening and TAV design improvement. To accomplish these goals, the following specific aims are proposed: 1) Investigation of elastic properties and microstructure of the human stenotic aortic root through a series of biomechanical tests performed on 50 human cadaver hearts;2) Image analysis of clinical CT scans, which will yield 60 reconstructed patient-specific aortic valve geometries. Statistical shape models will be developed to facilitate the reconstruction process as well as the description of anatomic geometric variation among the patient population;and 3) Probabilistic computational analysis of aortic tissue-TAV structural interaction and hemodynamics. Deterministic finite element (FE) models and computational fluid dynamics (CFD) models will be developed using 12 actual TAV patient data measured prior to the TAV intervention, and validated by the post-TAV clinical CT scans, flow and pressure measurements. A statistical description of patient material properties and geometric variations will be mapped into the computational models and a probabilistic analysis will be conducted to evaluate aortic tissue-TAV structural interaction and hemodynamics. The fundamental study of the biomechanics involved in TAV intervention and the computational modeling of tissue-implant interaction proposed here could lead to the development of a new knowledgebase that has been previously unavailable to academia, clinicians, and the heart valve industry. The methodologies and computational framework developed in this study will serve as a basis for future studies, which will include more design and environmental variables such as different patient demographics, and could also be utilized to facilitate the development of other novel device designs or pre-operative patient screening techniques for different valve diseases, such as mitral valve regurgitation.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL104080-02
Application #
8321981
Study Section
Special Emphasis Panel (ZRG1-BST-E (90))
Program Officer
Baldwin, Tim
Project Start
2011-08-20
Project End
2016-06-30
Budget Start
2012-07-01
Budget End
2013-06-30
Support Year
2
Fiscal Year
2012
Total Cost
$381,447
Indirect Cost
$50,037
Name
University of Connecticut
Department
Engineering (All Types)
Type
Schools of Engineering
DUNS #
614209054
City
Storrs-Mansfield
State
CT
Country
United States
Zip Code
06269
Li, Kewei; Sun, Wei (2016) Simulated transcatheter aortic valve deformation: A parametric study on the impact of leaflet geometry on valve peak stress. Int J Numer Method Biomed Eng :
Zuo, Keping; Pham, Thuy; Li, Kewei et al. (2016) Characterization of biomechanical properties of aged human and ovine mitral valve chordae tendineae. J Mech Behav Biomed Mater 62:607-18
Calderan, Joseph; Mao, Wenbin; Sirois, Eric et al. (2016) Development of an In Vitro Model to Characterize the Effects of Transcatheter Aortic Valve on Coronary Artery Flow. Artif Organs 40:612-9
Liu, Haofei; Sun, Wei (2016) Computational efficiency of numerical approximations of tangent moduli for finite element implementation of a fiber-reinforced hyperelastic material model. Comput Methods Biomech Biomed Engin 19:1171-80
Martin, Caitlin; Sun, Wei (2016) Transcatheter Valve Underexpansion Limits Leaflet Durability: Implications for Valve-in-Valve Procedures. Ann Biomed Eng :
Liang, Liang; Kong, Fanwei; Martin, Caitlin et al. (2016) Machine learning-based 3-D geometry reconstruction and modeling of aortic valve deformation using 3-D computed tomography images. Int J Numer Method Biomed Eng :
Martin, Caitlin; Sun, Wei (2015) Comparison of transcatheter aortic valve and surgical bioprosthetic valve durability: A fatigue simulation study. J Biomech 48:3026-34
Wang, Qian; Kodali, Susheel; Primiano, Charles et al. (2015) Simulations of transcatheter aortic valve implantation: implications for aortic root rupture. Biomech Model Mechanobiol 14:29-38
Martin, Caitlin; Sun, Wei; Elefteriades, John (2015) Patient-specific finite element analysis of ascending aorta aneurysms. Am J Physiol Heart Circ Physiol 308:H1306-16
Martin, Caitlin; Sun, Wei (2015) Fatigue damage of collagenous tissues: experiment, modeling and simulation studies. J Long Term Eff Med Implants 25:55-73

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