Anatomical associations with HALT in TAVR

Abstract Background/Purpose This sub-analysis of the prospective Low Risk TAVR (LRT) trial determined anatomical characteristics associated with hypoattenuated leaflet thickening (HALT), which may contribute to early transcatheter heart valve (THV) degeneration. Methods/Materials The LRT trial enrolled 200 low-risk patients between February 2016 and February 2018. All subjects underwent baseline and 30-day CT studies, analyzed by an independent core laboratory. Additional measurements, namely THV expansion, eccentricity, depth, and commissural alignment, were made by consensus of three independent readers. HALT was observed only in the Sapien 3 THV, so Evolut valves were excluded from this analysis. Results In the LRT trial, 177 subjects received Sapien 3 THVs, of whom 167 (94.3%) had interpretable 30-day CTs and were eligible for this analysis. Twenty-six subjects had HALT (15.6%). Baseline characteristics were similar between groups. There was no difference in THV size implanted and baseline aortic-root geometry between groups. In patients who developed HALT, THV implantation depth was shallower than in patients who did not develop HALT (2.6±1.1 mm HALT versus 3.3±1.8 mm no-HALT, p=0.03). There were more patients in the HALT group with commissural malalignment (40% vs. 28%; p=0.25), but this did not reach statistical significance. In a univariable regression model, no predetermined variable were shown to independently predict the development of HALT. Conclusions This study did not find anatomical or THV implantation characteristics that predicted the development of HALT at 30 days. This study cannot exclude subtle effects or interaction between factors because of the small number of events. Summary This sub-analysis of the prospective Low Risk TAVR trial found that hypoattenuated leaflet thickening (HALT) was associated with shallower transcatheter heart valve implantation. No predictors of HALT were found in a univariable regression analysis.