Effect of mitral annuloplasty device shape and size on leaflet and myofiber stress following repair of posterior leaflet prolapse: a patient-specific finite element simulation.

Background and Aim of the Study: Mitral annuloplasty (MA) devices are available in different shapes and sizes, but the preferred shape and size are unclear.
Methods: A previously described and validated finite element (FE) model of the left ventricle (LV) with mitral valve (MV) based on magnetic resonance imaging and three-dimensional echocardiography images from a patient with posterior leaflet (PL; P2) prolapse was used in this study. FE models of MA devices with different shapes (flat partial, shallow saddle, pronounced saddle) and sizes (36-30) were created. Virtual leaflet resection + MA with each shape and size were simulated. Leaflet geometry, stresses in the leaflets and base of the LV, and forces in the chordae and MA sutures were calculated.
Results: All MA shapes increased the mitral coaptation length, reduced the elevated PL stress at end-diastole (ED) and end-systole (ES) that occurred after leaflet resection, and reduced anterior leaflet (AL) stress at ES. MA devices of all shapes and sizes modestly reduced myofiber stress at the LV base in ED and ES. In general, saddle-shaped devices had the greatest effect.
Conclusion: All MA shapes increased coaptation length and reduced mitral leaflet stress and myofiber stress in the base of the LV. an additional reduction in MA size further increased coaptation length and reduced leaflet and myofiber stress. In general, saddle-shaped devices had the greatest effect.