Supra- vs. Intraannular Self-Expanding Transcatheter Heart Valves for Treatment of Aortic Valve Stenosis in Patients with Small Aortic Annuli

Background: Current evidence suggests hemodynamic superiority of supraannular self-expanding (SE) transcatheter heart valves (THV) compared with intraannular balloon-expandable (BE) THV in transcatheter aortic valve implantation (TAVI) for treatment of patients with small aortic annuli (≤23 mm). Whether this drawback of intraannular THV is due to valve position or stent design remains unclear. This non-inferiority study compares supra- and intraannular SE THV in small annuli.

Methods: This retrospective, single-center study included 63 patients (92.1% female, 83.2 ± 5.4 years) treated with intraannular SE THV, and 162 patients (84.0% female, 81.9 ± 6.2 years) treated with supraannular SE THV between 2021 and 2024. Early clinical and hemodynamic outcomes were evaluated in accordance with VARC-3 criteria.

Results: Intraannular THVs included 30.2% 23-mm and 69.8% 25-mm valves, whereas supraannular THVs consisted of 10.5% 23-mm and 89.5% 26-mm valves. Multivariate analysis of variance (MANOVA) validated similar baseline characteristics of both groups (p = 0.799). MANOVA of key VARC-3 endpoints revealed no significant overall differences (p = 0.815). Welch’s t-tests demonstrated no significant differences between THV platforms for the 30-day outcomes mortality (1.6% intraannular versus 1.9% supraannular, p = 0.236), pacemaker implantation (11.5% versus 14.1%, p = 0.724), stroke (1.6% versus 3.1%, p = 0.475), myocardial infarction (0.0% versus 1.2%, p = 0.158), renal failure (6.4% versus 8.0%, p = 0.776), and device success (96.2% versus 91.4%, p = 0.305). Postoperative transvalvular mean pressure gradients (6.7 ± 2.9 mm Hg versus 6.4 ± 3.5 mm Hg, p = 0.549), invasive post-implantation mean pressure gradients (11.9 ± 4.6 mm Hg versus 12.2 ± 6.0, p = 0.877), and paravalvular leak >mild (6.4% versus 0.6%, p = 0.073) presented no significant differences between valves. Minor access site complications (3.2% versus 11.7%, p = 0.012), and procedure time (55 minutes versus 72 minutes, p < 0.001) showed favorable results for the intraannular THV platform.

Conclusion: Intraannular SE THV presented non-inferiority in TAVI for small aortic annuli compared with supraannular SE THV regarding early clinical and hemodynamic outcomes. Both groups showed excellent outcomes, with similar postoperative transvalvular gradients suggesting crucial hemodynamic benefits of the Nitinol stent design in small aortic annuli. However, the durability of these hemodynamic results requires further investigation.

Publication History

Article published online:
11 February 2025