Background: Treatment of aortic stenosis in patients with small annuli is challenging and can result in prosthesis-patient mismatch (PPM).

Aims: We aimed to compare the forward flow haemodynamics and clinical outcomes of contemporary transcatheter valves in patients with small annuli.

Methods: The TAVI-SMALL 2 international retrospective registry included 1,378 patients with severe aortic stenosis and small annuli (annular perimeter <72 mm or area <400 mm2) treated with transfemoral self-expanding (SEV; n=1,092) and balloon-expandable valves (BEV; n=286) in 16 high-volume centres between 2011 and 2020. Analyses comparing SEV versus BEV and supra-annular (SAV; n=920) versus intraannular valves (IAV; n=458) included inverse probability of treatment weighting (IPTW). The primary endpoints were the predischarge mean aortic gradient and incidence of severe PPM. The secondary endpoint was the incidence of more than mild paravalvular leak (PVL).