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Failure Mechanics of Mitral Valve Chordae Tendineae Chordal rupture, the main cause of mitral valve insufficiency, often requires corrective surgery. To investigate the mechanisms of chordal rupture, failure mechanics were examined in porcine mitral chordae (37 anterior marginal, 40 anterior basal, 35 posterior marginal, and 38 posterior basal). Chordae were weighed, measured, and stretched to failure, then examined microscopically. Marginal chordae had 68% thinner cross-sectional areas and failed at 68% less load and 28% less strain than basal chordae. Posterior leaflet chordae were 35% thinner and failed at 43% less load and 22% less strain than anterior chordae. Chordae frequently tore just below the leaflet insertion, in what was often their narrowest section. Overall, marginal and posterior leaflet chordae were smaller and required less strain and load to fail. These results support previous reports of decreased extensibility in marginal chordae and the high incidence of posterior chordal ruptures. |
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