A bench study of balloon-expandable valves for the treatment of self-expanding valve failure

Background: Coronary obstruction and access are concerns in patients undergoing redo transcatheter aortic valve implantation (TAVI).

Aims: We sought to assess the neoskirt height, leaflet overhang, leaflet deflection,and transcatheter heart valve (THV) expansion and performance, at 2 different implant depths, of the SAPIEN 3 Ultra (S3U) within the ACURATE neo2 (ACn2) THV.

Methods: An in vitro study was performed with a 23 mm S3U deployed within a small (S) ACn2 and a 26 mm S3U deployed within a medium (M) and a large (L) ACn2. The S3U outflow was positioned at the top of the ACn2 crown (low implant) and at the base of the commissural post of the ACn2 (high implant). Testing was performed under physiological conditions as per ISO-5840-3 standard.

Results: The neoskirt height was shorter when the S3U outflow was positioned at a low implantation depth (S: 9.6 mm, M: 12.2 mm, L: 13.8 mm vs S: 15.2 mm, M: 15.1 mm, L: 17.8 mm ACn2 for high implants). Hydrodynamic performance was acceptable for all configurations. Leaflet overhang was <50% for all configurations except the low implant of the 26 mm S3U in the L ACn2 (77.6%). There was a gap from the side of the neoskirt to the outer border of the THV frame which was >2 mm for all configurations. The S3U was underexpanded for all configurations, and the achieved area was 77.9%-92.9% of the expected nominal area.

Conclusions: Redo TAVI with an S3U within an ACn2 has favourable hydrodynamics and moderate leaflet overhang. Importantly, the design of the ACn2 results in a neoskirt that is not deflected all the way to the outer dimensions of the THV, hence creating a space that facilitates coronary flow and access.