Patient-specific analysis of bicuspid aortic valve hemodynamics using a fully coupled fluid-structure interaction (FSI) model

Bicuspid aortic valve (BAV), the most common congenital heart disease, is prone to develop significant valvular dysfunction and aortic wall abnormalities. Growing evidence has suggested that abnormal BAV hemodynamics could contribute to the disease progression. In order to investigate the BAV hemodynamic, we performed 3D patient-specific fluid-structure interaction (FSI) simulations of BAV with fully coupled flow dynamics and valve motions throughout the cardiac cycle. The results showed that the flow during systole can be characterized by a systolic jet and two counter-rotating recirculation vortices. At peak systole, the jet was usually eccentric, with asymmetric recirculation vortices, and helical flow motion in the ascending aorta. The flow structure at peak systole was quantified using the vorticity, flow reversal ratio and helicity index at four locations from the aortic root to the ascending aorta. The systolic jet was evaluated using the metrics including the peak velocity, normalized flow displacement, and jet angle. It was found that both the peak velocity and normalized flow displacement (rather than jet angle) of the systolic jet showed a strong correlation with the vorticity and helicity index of the flow in the ascending aorta, which suggests that these two metrics can be used for noninvasive evaluation of abnormal flow patterns in BAV patients.