Self-expanding vs. balloon-expandable valves in small annulus patients undergoing transcatheter aortic valve implantation

Background Transcatheter aortic valve implantation (TAVI) in patients with a small aortic annulus represents a technical challenge due to the higher risk of patient-prosthesis mismatch, suboptimal haemodynamics, and procedural complications. Whether self-expanding valves (SEV) or balloon-expandable valves (BEV) offer superior outcomes in this anatomically challenging subgroup remains unknown. Purpose Purpose of our analysis is to compare SEV vs. BEV in patients with small annulus undergoing TAVI Methods We performed a retrospective analysis of a prospective, multicentre, observational investigator-initiated registry including consecutive patients undergoing TAVI at two high-volume tertiary centres between 2012 and 2024. The primary endpoint was long-term all-cause mortality over a median follow-up of 60 months. Secondary endpoints included VARC-3–defined technical success, device success, in-hospital mortality, periprocedural complications, and post-procedural echocardiographic valve performance. Survival was analysed using Kaplan-Meier estimates with log-rank testing. Multivariable Cox proportional hazards regression was performed adjusting for clinically relevant confounders. Results A total of 737 patients were included (BEV n=318, SEV n=419). The two groups were comparable for age, sex, BMI, and the majority of comorbidities. Pre-procedural echocardiography was comparable between groups. However, SEV patients had a higher prevalence of paced rhythm and more severe pre-TAVI mitral regurgitation. Technical success was high and comparable between groups (BEV 97.2% vs. SEV 97.3%, p=0.976), as was device success (BEV 90.3% vs. SEV 90.6%, p=0.919). In-hospital mortality was low and did not differ significantly. No significant differences were observed in permanent pacemaker implantation, stroke, vascular complications, or bleeding events. SEV were associated with significantly superior haemodynamic performance: lower mean gradient (9.0 [6.0–12.0] vs. 12.4 [10.0–16.0] mmHg, p<0.001), lower peak gradient (17.0 [12.0–22.5] vs. 23.0 [18.6–29.0] mmHg, p<0.001), and larger effective orifice area (AVA 1.77 [1.40–2.08] vs. 1.60 [1.29–1.98] cm², p=0.028). Kaplan-Meier analysis revealed no significant difference in overall survival between BEV and SEV over 5-year follow-up (log-rank p=0.394). On multivariable Cox regression adjusting for paced rhythm and pre-TAVI mitral regurgitation, valve type was not independently associated with mortality. Conclusions In patients with small aortic annuli treated with contemporary TAVI devices valve choice did not significantly affect long-term survival, technical success, device success, or major in-hospital outcomes. SEV provided superior post-procedural haemodynamics, which might offer clinical benefit in reducing patient-prosthesis mismatch in this challenging population. Prospective randomised trials specifically targeting the small annulus population are warranted.