Calcification Effect on the Wall Shear Stress Distribution of the Aortic Valve Leaflets

Wall shear stress on the aortic valve leaflets has been the main factor for the initiation and progression of calcific aortic valve disease (CAVD). This study aims to investigate the effects of leaflets stiffening and sinus diameter on sinus vortex structures, wall shear stress distribution on aortic valve leaflets as well as its correlation with CAVD. A two-dimensional fluid-structure interaction (FSI) model of healthy aortic valve leaflets was developed based on echocardiography images available in the literature. The turbulent flow downstream of the leaflets was considered in the model using ????? turbulent model. Results show that leaflets stiffening not only affects hemodynamic parameters within the aortic root such as transvalvular pressure gradient (TPG), jet velocity along with the valve, and valve orifice diameter but also has a significant effect on sinus vortex structures and wall shear stress distribution on the leaflets. The results demonstrate that severely calcified aortic valve witnesses lower ranges of shear stress on the leaflets during the systole and diastole (ranging from -0.5 to + 0.5 Pa for the systole and -0.1 to + 0.2 Pa for the diastole) with higher probability compared to those of with healthy valve which ranges from -1.5 to +2 Pa and -0.55 to + 0.55 Pa during the systole and diastole, respectively. It is also showed that wall shear stress on the leaflets is highly dependent on the diameter of the sinuses.