Effects of Implantation Height on the Performance of a Redo Transcatheter Aortic Valve Replacement Using a Balloon-Expandable Valve

Objective The use of the transcatheter aortic valve in low-risk patients might lead to a second intervention due to the deterioration of the first one. Understanding the implantation height is key to an effective redo TAVR treatment. Methods The effects of implantation height on the performance of a balloon-expandable valve within a self-expandable valve were assessed using hemodynamics testing and particle image velocimetry. The hemodynamic performances, leaflet kinematics, and turbulent shear stresses were measured and compared. Results When a second balloon-expandable valve was positioned at varying heights relative to the first self-expandable valve, the leaflet motion of the first valve transitioned from free opening and closing to overhanging, and eventually to being entirely pinned to the stent, forming a neo-skirt. When the leaflets of the self-expandable valve could move freely, a decrease in regurgitation fraction was observed, but with an increased pressure gradient across the valve. Flow visualization indicated that the overhanging leaflets disrupted the flow, generating a higher level of turbulence. Conclusions This study suggested that the overhanging leaflets should be avoided, while the other two scenarios should be carefully evaluated based on the individual patient’s anatomy and the cause of failure of the first valve.