Replacement of mitral valve posterior chordae tendineae with expanded polytetrafluoroethylene suture: a finite element study.
OBJECTIVE
Expanded polytetrafluoroethylene (ePTFE) suture has been used clinically for replacement of ruptured mitral valve chordae tendineae. The purpose of this study was to assess mitral valve function after posterior chordal replacement with ePTFE suture.


METHODS
A three-dimensional finite element computer model of the mitral valve was used, which incorporated geometry, regional tissue thickness, collagen fiber orientation, and anisotropic material properties for the leaflets, interface, and chordae tendineae. To simulate chordal rupture, four marginal and four basal chordae were removed from the posterior leaflet. Chordal replacement was simulated using two elements with the physical and material properties of 2-0 ePTFE suture. Systolic loading pressures were applied.


RESULTS
The chordal rupture model demonstrated posterior leaflet prolapse, abnormal stress concentrations, potential regurgitation, and elevated chordal stress. Conversely, the chordal replacement model corrected the prolapse and returned chordal stress to normal levels. However, stress concentrations were shown at suture attachment points.


CONCLUSIONS
This integrated mitral valve finite element model provides a tool to investigate the performance of the valve system. In this study, we have shown that 2-0 ePTFE suture replacement of ruptured posterior chordae tendineae returns the valve to a near normal state, in terms of leaflet stress and coaptation, and chordal stresses.
Kunzelman
K
K
Division of Cardiothoracic Surgery, University of Washington, Seattle 98195-6310, USA. karynk@u.washington.edu
Reimink
M S
MS
Verrier
E D
ED
Cochran
R P
RP
D016880:Anisotropy; D001672:Biocompatible Materials / Q000737:chemistry; D001794:Blood Pressure; D002302:Cardiac Output; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D002815:Chordae Tendineae / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D003094:Collagen / Q000737:chemistry; D003198:Computer Simulation; D006349:Heart Valve Diseases / Q000601:surgery; D006801:Humans; D008943:Mitral Valve / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D008944:Mitral Valve Insufficiency / Q000473:pathology / Q000503:physiopathology / Q000601:surgery; D008945:Mitral Valve Prolapse / Q000473:pathology / Q000503:physiopathology / Q000601:surgery; D008955:Models, Cardiovascular; D011138:Polytetrafluoroethylene / Q000737:chemistry; D012422:Rupture, Spontaneous; D013314:Stress, Mechanical; D013537:Sutures
D001672:Biocompatible Materials; D011138:Polytetrafluoroethylene; D003094:Collagen