Background: Aortic annulus size impacts valve hemodynamics and clinical outcomes after transcatheter aortic valve replacement (TAVR). However, it is not known whether the selection of balloon-expandable valve (BEV) versus self-expanding valve (SEV) affects hemodynamics differently in patients with small, medium or large aortic annulus.
Methods: Consecutive patients undergoing TAVR with a balloon-expandable or self-expanding valve at Washington Hospital Center between 2013 and 2015 were included. Data were prospectively collected, including baseline and procedural characteristics, 30-day and 1-year mortality. Patients were grouped into tertiles based on CT angiography-derived aortic annulus perimeter measured in systole. The pre-discharge echocardiogram was analyzed for prosthetic valve hemodynamics.
Results: 193 patients were included in the study. Patients with small aortic annulus were more likely female, with lower body surface area, and smaller iliac arteries. Tertile perimeter cutoffs were 73mm and 80mm. STS score decreased as annulus size increased (7.8% vs. 7.6% vs. 6.0%, p=<0.05 for small, medium and large annulus respectively). In patients with small annulus, SEV was associated with significantly higher dimensionless index (0.64 vs. 0.53, p=0.02) and lower peak velocity (1.8 vs. 2.4m/sec, p<0.001), and a trend towards lower mean gradient (7.5 vs. 10.0mmHg, p=0.07) compared with BEV. These differences were attenuated and absent in patients with medium and large annulus respectively. Very few patients had moderate/severe paravalvular leak, with no significant association with valve type or annulus size. There was no difference in mortality between tertiles or valve type at 30 days or 1 year. There was no association between aortic annulus perimeter and 1-year mortality by univariate analysis (HR 1.00, 95% CI 0.95–1.05, p=0.86) or multivariate analysis (HR 1.02, 95% CI 0.95–1.09, p=0.60).
Conclusions: In patients with small aortic annulus, SEV hemodynamics are superior to BEV. This difference is diminished in patients with larger aortic annulus. This study highlights the importance of TAVR valve selection in patients with small aortic annulus.