Redo-TAVI with the SAPIEN 3 valve in degenerated calcified CoreValve/Evolut explants

BACKGROUND: Redo-transcatheter aortic valve implantation (TAVI) is the treatment of choice for failed transcatheter aortic valves. Currently, implantation of a SAPIEN 3 (S3) is indicated for redo-TAVI in degenerated CoreValve/ Evolut (CV/EV) transcatheter aortic valves (TAVs) but is not well understood. AIMS: We aimed to evaluate S3 function following implantation in explanted calcified CV/EV TAVs and to assess the impact of CV/EV pathology on redo-TAVI outcomes. METHODS: Ex vivo hydrodynamic testing was performed per the International Organization for Standardization (ISO) 5840-3 standard on 4 S3 TAVs implanted at node 5 in calcified CV/EV explants. The mean gradient (MG), effective orifice area (EOA), peak velocity, regurgitant fraction (RF), geometric orifice area (GOA), leaflet overhang, leaflet pinwheeling, neoskirt height, and frame deformation were evaluated. RESULTS: CV/EV explants were calcified and stenotic. Following S3 implantation, the MG and peak velocity decreased. As per the ISO standard, all S3 implants showed adequate EOA, and 3 out of 4 had an RF within the accepted value (<20%). CV/EV leaflet overhang ranged from 25-37%. Calcified leaflets remained stationary throughout the cardiac cycle (difference <9%) and were not pinned in a manner that constrained S3 systolic flow or appeared to prevent selective frame cannulation. The downstream CV/EV GOA was larger than the upstream S3 GOA during systole. S3 frame underexpansion was seen, resulting in leaflet pinwheeling (range 13-30%). Above the neoskirt, calcium protrusion was observed in contact with the S3 leaflets. CONCLUSIONS: S3 implantation at node 5 in calcified CV/EV valves resulted in satisfactory hydrodynamic performance in most configurations tested with stable leaflet overhang throughout the cardiac cycle. The long-term implications of S3 underexpansion, leaflet pinwheeling, and calcium protrusion require future studies.