A Geometry Optimization Framework for Transcatheter Heart Valve Leaflet Design

Transcatheter aortic valve replacement (TAVR) is an established treatment for patients with severe symptomatic aortic stenosis. It is known and recognized that leaflet geometry has a key role in structural and hemodynamic performance of bioprosthetic heart valves. Excessive mechanical stress on the leaflets will lead to accelerated tissue degeneration and diminished long-term valve durability. The goal of this study was to develop an automatic optimization framework by means of commercially available software packages to reduce maximum stress value of transcatheter aortic valve (TAV) leaflets. Leaflet design was parameterized by 2 s-order non-uniform rational B-splines (NURBS) curves and particle swarm optimization method was used to examine the optimization design space. Optimized leaflet geometry for 23-mm and 26-mm TAVs were obtained under dynamic physiological loading condition. Leaflet stress distributions of the optimized TAV geometries were compared with two commercially available bioprostheses (i) Carpentier-Edwards PERIMOUNT Magna surgical bioprosthesis and (ii) Edwards SAPIEN 3 transcatheter heart valve. A considerable reduction in the maximum in-plane principal stress was observed in the optimized TAV geometries compared to the commercially available bioprostheses. The optimization results underline the opportunity to improve leaflet design in the next generation of TAVs to potentially increase long-term durability of transcatheter heart valves