Augmented Mitral Valve Leaflet Area Decreases Leaflet Stress: a Finite Element Simulation

Background—Using human MV models derived from three-dimensional (3D) echocardiography, finite element analysis (FEA) was used to predict mechanical leaflet and chordal stress. Subsequently, valve geometries were altered to examine the effects on stresses of: (1) varying coaptation area, (2) varying non-coapted leaflet tissue area, and (3) varying interleaflet coefficient of friction (μ). Methods—Three human MV models were loaded with a transvalvular pressure of 80 mmHg using FEA. Initially leaflet coaptation was set to 10%, 50%, or 100 % of actual coaptation length to test the influence of coaptation length on stress distribution. Next, leaflet surface areas were augmented by 1 % overall and by 2 % in the noncoapted “belly ” region to test the influence of increased leaflet billowing without changing the gross geometry of the MV. Finally, the coefficient of friction between the coapted leaflets was set to μ = 0, 0.05, or 0.3, to assess the influence of friction on MV function. Results—Leaflet coaptation length did not affect stress distribution in either the coapted or noncoapted leaflet regions: peak leaflet stress was 0.36±0.17 MPa at 100%, 0.35±0.14 MPa a