Transcatheter Self-Expandable Valve Implantation for Aortic Stenosis in Small Aortic Annuli: The TAVI-SMALL Registry

Abstract

Objectives: The aim of this study was to evaluate and compare the outcomes of transcatheter self-expandable prostheses in patients with small annuli.

Background: Transcatheter aortic heart valves appear to have better performance than surgical valves in terms of prosthesis-patient mismatch, especially in patients with aortic stenosis with small aortic annuli.

Methods: TAVI-SMALL (International Multicenter Registry to Evaluate the Performance of Self-Expandable Valves in Small Aortic Annuli) is a retrospective registry of patients with severe aortic stenosis and small annuli (annular perimeter <72 mm or area <400 mm² on computed tomography) treated with transcatheter self-expandable valves (n = 859; Evolut R, n = 397; Evolut PRO, n = 84; ACURATE, n = 201; Portico, n = 177). Primary endpoints were post-procedural mean aortic gradient, indexed effective orifice area, and rate of severe prosthesis-patient mismatch.

Results: Pre-discharge gradients were consistently low in every group, with a slight benefit with the Evolut R (8.1 mm Hg; 95% confidence interval [CI]: 7.7 to 8.5 mm Hg) and Evolut PRO (6.9 mm Hg; 95% CI: 6.3 to 7.6 mm Hg) compared with the ACURATE (9.6 mm Hg; 95% CI: 8.9 to 10.2 mm Hg) and Portico (8.9 mm Hg; 95% CI: 8.2 to 9.6 mm Hg) groups (p < 0.001). Mean indexed effective orifice area was 1.04 cm²/m² (95% CI: 1.01 to 1.08 cm²/m²) with a trend toward lower values with the Portico. No significant differences were reported in terms of severe prosthesis-patient mismatch (overall rate 9.4%; p = 0.134), permanent pacemaker implantation (15.6%), and periprocedural and 1-year adverse events. Pre-discharge more than mild paravalvular leaks were significantly more common with the Portico (19.2%) and less common with the Evolut PRO (3.6%) compared with the Evolut R (11.8%) and ACURATE (9%) groups.

Conclusions: Transcatheter self-expandable valves showed optimal clinical and echocardiographic results in patients with small aortic annuli, although supra-annular functioning transcatheter heart valves seemed to slightly outperform intra-annular functioning ones. The role of transcatheter aortic valve replacement with self-expandable valves for the treatment of aortic stenosis in patients with small annuli needs to be confirmed in larger trials.

Keywords: TAVR; self-expandable valves; small annuli.