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 #
5R01HL119297-02
Application #
8726481
Study Section
Special Emphasis Panel (ZRG1-SBIB-N (55))
Program Officer
Evans, Frank
Project Start
2013-09-01
Project End
2018-05-31
Budget Start
2014-06-01
Budget End
2015-05-31
Support Year
2
Fiscal Year
2014
Total Cost
$1,308,096
Indirect Cost
$145,344
Name
University of Texas Austin
Department
Engineering (All Types)
Type
Schools of Engineering
DUNS #
170230239
City
Austin
State
TX
Country
United States
Zip Code
78712
Songia, Paola; Branchetti, Emanuela; Parolari, Alessandro et al. (2016) Mitral valve endothelial cells secrete osteoprotegerin during endothelial mesenchymal transition. J Mol Cell Cardiol 98:48-57
Zhang, Will; Ayoub, Salma; Liao, Jun et al. (2016) A meso-scale layer-specific structural constitutive model of the mitral heart valve leaflets. Acta Biomater 32:238-55
Pierce, Eric L; Bloodworth 4th, Charles H; Naran, Ajay et al. (2016) Novel Method to Track Soft Tissue Deformation by Micro-Computed Tomography: Application to the Mitral Valve. Ann Biomed Eng 44:2273-81
Sakamoto, Yusuke; Buchanan, Rachel M; Sacks, Michael S (2016) On intrinsic stress fiber contractile forces in semilunar heart valve interstitial cells using a continuum mixture model. J Mech Behav Biomed Mater 54:244-58
Bloodworth 4th, Charles H; Pierce, Eric L; Easley, Thomas F et al. (2016) Ex Vivo Methods for Informing Computational Models of the Mitral Valve. Ann Biomed Eng :
Lee, Chung-Hao; Carruthers, Christopher A; Ayoub, Salma et al. (2015) Quantification and simulation of layer-specific mitral valve interstitial cells deformation under physiological loading. J Theor Biol 373:26-39
Kamensky, David; Hsu, Ming-Chen; Schillinger, Dominik et al. (2015) An immersogeometric variational framework for fluid-structure interaction: application to bioprosthetic heart valves. Comput Methods Appl Mech Eng 284:1005-1053
Lee, Chung-Hao; Rabbah, Jean-Pierre; Yoganathan, Ajit P et al. (2015) On the effects of leaflet microstructure and constitutive model on the closing behavior of the mitral valve. Biomech Model Mechanobiol 14:1281-302
Lee, Chung-Hao; Zhang, Will; Liao, Jun et al. (2015) On the presence of affine fibril and fiber kinematics in the mitral valve anterior leaflet. Biophys J 108:2074-87
Fan, Rong; Sacks, Michael S (2014) Simulation of planar soft tissues using a structural constitutive model: Finite element implementation and validation. J Biomech 47:2043-54

Showing the most recent 10 out of 14 publications