Why is this study important? 

The condition of small aortic annuli is a problem that largely affects women and there is currently clinically equipoise regarding best transcatheter valve selection to treat these patients. Data from the 12 months results of the randomized SMART trial suggests treatment of small aortic annuli with a self-expanding valve (SEV) is superior to balloon expandable valves (BEV). 

What question was this study supposed to answer?   

This study is intended to provide a two-year update to the original SMART trial. The SMART Trial randomized 716 patients at 83 sites across 13 countries with small aortic annuli (<430 mm2) in a 1:1 fashion to transcatheter aortic valve replacement (TAVR) with a BEV or a SEV. Initial trial data showed that SEV were non-inferior to BEV regarding the composite co-primary outcome of mortality, disabling stroke, or heart failure hospitalizations at 12 months. However, SEV were superior to BEV regarding the composite co-primary outcome of bioprosthetic valve dysfunction (BVD) at 12 months. The SMART trial is planned for a five-year follow-up.  

What did the study show?   

The 2-year update continues to show that SEV (9.4%) are non-inferior to BEV (10.6%) regarding the composite co-primary endpoint of mortality, disabling stroke, and heart failure hospitalizations. SEVs remain superior to BEV regarding the composite co-primary endpoint of bioprosthetic valve dysfunction. Specifically, 48.4% of patients treated with a BEV experienced BVD at two years versus 12.5% of patients treated with a SEV (p <0.001) across the entire studied annular range.  

Patients treated with a SEV enjoyed higher EOA (1.9 cm2) and lower mean gradients (8.5 mmHg) at 2 years compared to patients treated with a BEV, 1.51 cm2 and 16.1 mmHg, respectively.  

At 2 years, 22.7% of patients treated with a BEV had a mean gradients > 20mmHg versus 1.2% in the SEV group (p <0.001). Core lab adjudicated valve thrombosis occurred in 15 patients in the BEV groups vs 3 in the SEV group (p 0.005) with the majority of these being subclinical.