Influence of Vortices in the Sinus of Valsalva on Local Wall Shear Stress Distribution

Abstract

Transposition of the great arteries (TGA) is one of the most severe congenital heart diseases. The arterial switch operation (ASO) is the procedure of preference for treatment of TGA. After ASO, some patients suffer from circulatory system problems such as neo-aortic root dilatation and neo-aortic valve regurgitation, and supravalvar pulmonary stenosis. The neo-aortic root dilatation is often explained by the structural vascular difference between normal great arteries and the neo-aorta after ASO. Since the aortic and pulmonary roots generally remain in situ after ASO, i.e., the original pulmonary artery is connected to the left ventricle (LV), whereas the original aorta is connected to the right ventricle, the neo-aorta has no sinus of Valsalva after ASO. The influence of these morphological changes on the blood flow field at the aortic root should be investigated in detail as well as the structural vascular difference to consider the circular system problems. In this study, we apply the virtual flux method (VFM), which is a tool to describe stationary or moving body shapes in a Cartesian grid, to the 2D aortic valves and reproduce the blood flow fields around the aortic valves and the sinus of Valsalva by regularized lattice Boltzmann method (RLBM), and consider the influence of longitudinal length of sinus of Valsalva on blood flow fields around the aortic valves. As a result, we found that the longitudinal length of the sinus affects development of vortices around the aortic valves strongly. We also assessed the wall shear stress (WSS) distribution on the aortic valves and sinus wall and showed the effect of vortices in the sinus of Valsalva on local WSS distribution.