Fluid structure interaction analysis of a calcified aortic valve

Abstract

The aim of this paper is to investigate the effect of calcification of the aortic-valve leaflets on the flow pattern and hemodynamic parameters such as transvalvular pressure gradient and valve orifice area based on fluid structure interaction modelling methodology using ANSYS. The geometry has been developed in ANSYS Workbench based on echocardiography images available in the literature. A pulsatile inlet velocity extracted from Doppler velocity measurement data in the literature has been used as an inlet boundary condition. For modelling the turbulent flow downstream of the leaflets, the k- SST turbulence model was used. For comparison, both healthy and calcified aortic valves were modelled and analysed. Results show that the transvalvular pressure gradient increases from 769 Pa for the healthy aortic valve to 2356 Pa for the calcified one. Furthermore, there is a significant decrease in the valve orifice diameter, from 13.5 mm for the healthy aortic valve leaflets to 9.21 mm for the calcified one. It was also shown that the wall shear stress on fibrosa and ventricular layers of the leaflets are significantly changed as a result of change in the thickness and material properties of the leaflets. Averaged wall shear stress on the ventricular surface increases from 16.3 Pa for the healthy case to 23.8 Pa for the calcified aortic valve. For the fibrosa surface, it decreases from 3.42 Pa for the healthy leaflets to 1.53 Pa for the calcified one.