After two decades of emphasis on valve replacement, cardiac surgeons have been gradually turning to mitral valve repair. MV repair, rather than replacement, maintains better ventricular mechanics and fewer complications, such as endocarditis, thromboembolism, and anticoagulant-related hemorrhage. Unfortunately, recent long term studies using more rigorous definitions of failure have identified less optimistic result for repair durability; bringing into question such aggressive surgical practice and suggesting that repair techniques though mature can be improved upon. In most cases, failures were a result of disruption at the leaflet, chordal, or annular suture lines. These failure modes suggest excessive tissue stress and the resulting strain induced tissue damage as an etiologic factor. Thus, there has been growing interest in developing more robust repair strategies for patients with IMR. Promising concepts include leaflet augmentation to restore leaflet mobility, and saddle shaped annuloplasty to restore normal annular shape. If designed correctly, leaflet augmentation techniques can alleviate chordal-leaflet tethering and reduce leaflet stress by promoting leaflet curvature and coaptation. Leaflet augmentation will also allow the placement of larger annuloplasty rings that should reduce annular-annuloplasty ring separation forces. We thus hypothesize that IMR repair techniques that reinstate normal annular geometry (size and shape) and restore mobile leaflet tissue will result in reduced annular and chordal force distribution compared with undersized flat annuloplasty alone. This in turn will lead to restoration of homeostatic normal tissue stress levels and MVIC biosynthetic responses, ultimately leading to improved repair durability.

Public Health Relevance

After two decades of emphasis on valve replacement, cardiac surgeons have been gradually turning to mitral valve repair. Thus, we plan on developing a comprehensive model to optimize the restoration of homeostatic normal tissue stress levels leading to improved valve repair durability.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
4R01HL119297-04
Application #
9061815
Study Section
Special Emphasis Panel (ZRG1)
Program Officer
Evans, Frank
Project Start
2013-09-01
Project End
2018-05-31
Budget Start
2016-06-01
Budget End
2017-05-31
Support Year
4
Fiscal Year
2016
Total Cost
Indirect Cost
Name
University of Texas Austin
Department
Engineering (All Types)
Type
Biomed Engr/Col Engr/Engr Sta
DUNS #
170230239
City
Austin
State
TX
Country
United States
Zip Code
78712
Easley, Thomas F; Bloodworth 4th, Charles H; Bhal, Vinay et al. (2018) Effects of annular contraction on anterior leaflet strain using an in vitro simulator with a dynamically contracting mitral annulus. J Biomech 66:51-56
Drach, Andrew; Khalighi, Amir H; Sacks, Michael S (2018) A comprehensive pipeline for multi-resolution modeling of the mitral valve: Validation, computational efficiency, and predictive capability. Int J Numer Method Biomed Eng 34:
Khalighi, Amir H; Drach, Andrew; Gorman, Robert C et al. (2018) Multi-resolution geometric modeling of the mitral heart valve leaflets. Biomech Model Mechanobiol 17:351-366
Bloodworth 4th, Charles H; Pierce, Eric L; Easley, Thomas F et al. (2017) Ex Vivo Methods for Informing Computational Models of the Mitral Valve. Ann Biomed Eng 45:496-507
Sakamoto, Yusuke; Buchanan, Rachel M; Sanchez-Adams, Johannah et al. (2017) On the Functional Role of Valve Interstitial Cell Stress Fibers: A Continuum Modeling Approach. J Biomech Eng 139:
Rego, Bruno V; Sacks, Michael S (2017) A functionally graded material model for the transmural stress distribution of the aortic valve leaflet. J Biomech 54:88-95
Lee, Chung-Hao; Zhang, Will; Feaver, Kristen et al. (2017) On the in vivo function of the mitral heart valve leaflet: insights into tissue-interstitial cell biomechanical coupling. Biomech Model Mechanobiol 16:1613-1632
Khalighi, Amir H; Drach, Andrew; Bloodworth 4th, Charles H et al. (2017) Mitral Valve Chordae Tendineae: Topological and Geometrical Characterization. Ann Biomed Eng 45:378-393
Soares, João S; Zhang, Will; Sacks, Michael S (2017) A mathematical model for the determination of forming tissue moduli in needled-nonwoven scaffolds. Acta Biomater 51:220-236
Goth, Will; Lesicko, John; Sacks, Michael S et al. (2016) Optical-Based Analysis of Soft Tissue Structures. Annu Rev Biomed Eng 18:357-85

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