Finite element evaluation of stresses on closed leaflets of bioprosthetic heart valves with flexible stents

Abstract The purpose of this study is to evaluate the influence of stent flexibility on the magnitude and distribution of stresses on the closed leaflets of a porcine bioprosthetic valve. The finite element technique which incorporated large deformation theory has been used in the analysis. Nonlinearities due to geometry, material and pressure dependent boundary conditions are included in the model. An incremental method has been employed in determining the stresses. The pressure was incremented from 0 to 21.3 kPa. Three separate stent flexibilities were considered and this was achieved by modifying the Young's modulus of the stent material. The calculated radial deflections of the tip of the stent post were in agreement with the results of other investigators. The distribution of stresses in the leaflet of a valve mounted on a flexible stent were compared to the stresses in the leaflet of a valve mounted on a rigid stent. Stent flexibility markedly reduced the stresses in the main body of the leaflet in comparison to a rigid stent, but did not affect the magnitude of stresses near commissures.