Dynamics of transcatheter heart valves with an in vitro experiment incorporating particle image velocimetry

The malfunctioning heart valve will compromise the cardiovascular circulation of the human body. Given that artificial valves can be used to replace a disabled one, a feasible in vitro evaluation system is important before any possible implantation. In this study, two types of transcatheter heart valves, namely, V-A (diameter: 23 mm) and V-B (diameter: 25 mm), are tested and compared by an in vitro experiment that incorporates a circulation system and a particle image velocimetry measuring module. Three dynamical indices, namely, the time-averaged wall shear stress, oscillatory shear index, and relative residence time, are applied for the evaluation. The results show that compared with V-B, V-A leads to lower probabilities of vessel wall damage and thrombosis formation, especially when the flow rate is close to that of the human body (4 l/min). Meanwhile, an independent analysis, which mainly concerns the mean pressure difference and regurgitation volume across the two ends of the valve, demonstrates that V-A has a better performance than V-B, thus verifying the above-mentioned analysis from the perspective of fluid dynamics. Therefore, the present in vitro measuring system is considered effective in evaluating the valve functionality.