起旋式人工主动脉瓣构型设计及血流动力学评价

Objective To design a bileaflet mechanical valve with the function of generating helical flow, so as to prevent postoperative complications by improving its hemodynamic characteristics. Methods Based on the structure of guiding-vane type spiral flow generator, the leaflets were used as the guiding vane and the leaflet wrap angle was defined to explore the valve configuration with better hemodynamic performance. The finite element analysis software was used to simulate the aortic flow field under the state of peak systolic flow. Then the flow velocity, effective orifice area (EOA), flow asymmetry and helicity, wall shear stress (WSS) distribution and other hemodynamic characteristics in each group were compared. Results Compared with the control valve, the helical-flow-generated valve had a larger EOA and a smaller pressure difference across the valve. The helical-flow-generated-valve with leaflets within a certain wrap angle could promote the generation of right-handed helical flow and make the blood flow approach the center of the channel. The WSS distribution was more uniform and the peak WSS was relatively smaller in the helical-flow-generated valve, with fewer low-stress and high-stress areas. For the aortic model in this study, the leaflet wrap angle for optimal hemodynamic performance was 15°-20°. Conclusions This novel artificial aortic valve can adjust blood flow characteristics in the aorta, reduce the risk of aortic dilatation and aortic aneurysm caused by aortic valve replacement, and it has guiding significance for configuration design of mechanical valve in the future.