Background: A small aortic annulus (SAA) is a risk factor for prosthesis-patient mismatch (PPM) in patients undergoing surgical or transcatheter aortic valve implantation (TAVI). Data regarding TAVI in patients with extra-SAA are scarce.

Aims: The aim of this study was to analyse the safety and efficacy of TAVI in patients with extra-SAA.

Methods: A multicentre registry study including patients with extra-SAA (defined as an aortic annulus area <280 mm2 and/or perimeter <60 mm) undergoing TAVI was established. Primary efficacy and safety endpoints were defined as device success and early safety at 30 days, respectively, using the Valve Academic Research Consortium-3 criteria, and were analysed according to valve type: self-expanding (SEV) versus balloon-expandable (BEV).

Results: A total of 150 patients were included, of which 139 (92.7%) were women, and 110 (73.3%) received an SEV. Intraprocedural technical success was 91.3%, with a higher rate in patients receiving an SEV (96.4% vs 77.5% with BEV; p=0.001). Overall, 30-day device success was 81.3%, (85.5% with SEV vs 70.0% with BEV; p=0.032). The primary safety endpoint occurred in 72.0% of patients (with no difference between groups; p=0.118). Severe PPM occurred in 12% (9.0% with SEV and 24.0% with BEV; p=0.039), with no impact on all-cause mortality, cardiovascular mortality, or heart failure readmission at 2-year follow-up.

Conclusions: TAVI is a safe and feasible treatment in patients with extra-SAA with a high rate of technical success. The use of SEV was associated with a lower rate of intraprocedural complications, higher device success at 30 days and better haemodynamic outcomes compared to BEV.