Transcatheter Aortic Valve Implantation in Small and Very Small Aortic Valve Annuli: A Propensity-Matched Analysis Between Self-Expanding Versus Balloon-Expandable Valves

Background: The management of Transcatheter Aortic Valve Implantation (TAVI) patients with a small aortic annulus (SAA) postures a substantial challenge, increasing the risk of patient- prosthesis mismatch (PPM) and overall mortality. Aims: This study aimed to compare the hemodynamic and clinical outcomes of transcatheter balloon-expandable valve (BEV) versus transcatheter self-expandable valve (SEV) in SAA. Methods: We conducted propensity score matching (PSM) of severe AS patients with SAA who underwent trans-femoral TAVR and enrolled to the Israeli TAVR registry between the years 2008 and 2023. SAA was defined as an aortic-valve annulus area <= 430 mm2. Since the BEV used have a smaller size cut-off, an additional analysis on very small aortic annulus (vSAA) as defined as aortic-valve annulus area <= 345 mm2 was performed. Results: The study included 1364 consecutive patients with SAA of (BEV n = 485; SEV n = 879) at a mean age of 82 +/- 7 years, of whom the vast majority were female (83%). Propensity-matched groups comprised of 329 and 122 paired for the SAA and vSAA patients, respectively. As compared to BEV in the SAA and vSAA analyses, SEV showed lower rates of postprocedural of LBBB (32% vs. 22% and 41% vs. 22%; both p < 0.01, respectively), however, higher rates of major vascular complications (2% vs. 7% and 2% vs. 12%; both p < 0.01, respectively) and major or life-threatening bleeding but only in vSAA group (17% vs. 9.1%, p = 0.009). One-month mortality was higher in the SEV versus BEV in both SAA and vSAA comparisons (2% vs. 0.6%, p = 0.048 and 3% vs. 0%, p = 0.018; respectively). A nonsignificant trend of higher 5-year mortality was observed in univariate models, noted mainly in vSAA patients (22% vs. 19%, p = 0.385; 24% vs. 15%, p = 0.073). Conclusions: The present analysis observed higher rates of major vascular complications and 1-month mortality in SAA and vSAA treated with SEV. A similar nonsignificant trend toward long-term mortality for the vSAA group was observed and should be evaluated in larger cohorts.