Balloon-Expandable Valves Versus Self-Expanding Valves in Patients With Small Aortic Annulus Undergoing Transcatheter Aortic Valve Replacement: A Systematic Review and Meta-Analysis

Patients with a small aortic annulus (SAA) undergoing transcatheter aortic valve replacement (TAVR) face a high risk of prosthesis-patient mismatch and adverse outcomes. The 2 most studied valve types, balloon-expandable valves (BEVs) and self-expanding valves (SEVs), differ in structure and deployment, potentially impacting outcomes in this subgroup. To compare the hemodynamic and clinical outcomes of BEVs versus SEVs in SAA patients undergoing TAVR. A systematic search of major databases through March 2025 identified randomized controlled trials and propensity score matching studies comparing BEVs and SEVs. Pooled analyses were conducted using a random-effects model to derive mean differences (MDs) and odds ratios (ORs) with 95% confidence intervals (CIs) in R (version 4.4.1). Thirteen studies (n = 4582; BEV: 2290; SEV: 2292) were included. BEVs were associated with smaller indexed effective orifice area (iEOA) (MD: -0.15 cm²/m²), higher mean (MD: 4.92 mm Hg) and peak (MD: 4.78 mm Hg) transvalvular gradients, and higher overall (OR: 2.64) and severe (OR: 2.72) prosthesis-patient mismatch rates. However, BEVs had a significantly lower risk of permanent pacemaker implantation (OR: 0.62). No significant differences were found in mortality, stroke, bleeding, acute kidney injury, paravalvular leak, myocardial infarction, vascular complications, or heart failure hospitalization. BEVs and SEVs demonstrate comparable mortality in SAA patients undergoing TAVR. SEVs offer superior hemodynamic outcomes, while BEVs reduce pacemaker need. Prosthetic valve selection should be individualized based on anatomy, clinical profile, and procedural factors. Future randomized trials with long-term follow-up are warranted to inform optimal device selection in this population.