In-vitro analysis of neo-sinus flow dynamics after transcatheter aortic valve replacement using particle image velocimetry technique

Particle imaging velocimetry (PIV) is an effective methodology for investigating flow in the neo-sinus after transcatheter aortic valve replacement. However, understanding fluid dynamics in the lower part of the neo-sinus has been challenging due to limited optical access. In this study, we developed a novel PIV technique to extensively visualize the neo-sinus and to assess the potential risk of transcatheter heart valve (THV) leaflet thrombosis with the intra-annular valve. This technique involved shooting in the sinus and neo-sinus via the ventral wall of the aortic silicone model to visualize a larger region of the neo-sinus, including the lower portions (overlooking-view shooting). In the neo-sinus, stagnated flow was observed throughout the entire region in middle and late diastole. By contrast, in the native sinus, low-velocity vortical flow that inflows into the coronary artery was developed exclusively in the upper region. The present results suggest that the lower portion of the native sinus, as well as the neo-sinus, may be at high risk for leaflet thrombosis. The novel PIV technique holds promise for revealing influences of fluid dynamics on THV leaflet thrombosis with various stent flame designs.