AIMS: This study aimed to assess the potential relationship between subclinical leaflet thickening and stent frame geometry in patients who underwent aortic valve replacement with a self-expanding transcatheter heart valve (THV).

METHODS AND RESULTS: Seventy-five patients with a self-expanding THV were studied with 4D-computed tomography and analysed for leaflet thickening. There was no difference in THV size, overall THV expansion, eccentricity or implantation depth between patients with and those without leaflet thickening. Moderate-to-severe regional THV underexpansion (≤90°) more frequently occurred at the non-coronary and right coronary cusps with a significantly higher incidence of leaflet thickening than in cases of full regional THV expansion (24% vs. 3%, p<0.01). Regional THV underexpansion at the inflow level more often translated into the same issue at the valvular level in THV with intra-annular as compared to supra-annular valve position (54% vs. 17%; p=0.04). In case of post-dilatation, regional THV underexpansion occurred less frequently as compared to THV that were not post-dilated (18% vs. 43%, p=0.028). A similar but non-significant trend was found for leaflet thickening.

CONCLUSIONS: Regional THV stent frame underexpansion is associated with an increased risk of leaflet thickening. Post-dilatation of self-expanding THV as well as a supra-annular valve position seem to reduce the occurrence of this phenomenon.