Balloon-expandable valve vs. self-expandable valve for small aortic annuli: a GRADE-assessed systematic review and updated meta-analysis.

INTRODUCTION

Aortic stenosis is a prevalent and serious heart valve disorder, particularly affecting older adults. A significant subset of these patients presents with small aortic annuli (SAA), complicating the selection of optimal transcatheter aortic valve replacement (TAVR) devices. The comparative efficacy and safety of balloon-expandable valves (BEV) vs. self-expandable valves (SEV) for this subgroup remain uncertain.

PURPOSE: This systematic review and meta-analysis aimed to evaluate and compare the clinical and hemodynamic outcomes of BEV and SEV in patients with SAA undergoing TAVR, using the GRADE approach to assess the certainty of evidence.

METHODS

A comprehensive electronic search was conducted in PubMed, Embase, Scopus, and other databases up to July 2025. Studies were included if they compared BEV and SEV in patients with SAA. Data extraction and quality assessment followed the Cochrane and PRISMA guidelines. The primary outcomes were new permanent pacemaker implantation and paravalvular leak greater than mild. Secondary outcomes included indexed effective orifice area, mean transvalvular gradient, and prosthesis-patient mismatch (PPM). Random-effects meta-analyses were performed to pool odds ratios (ORs) or mean differences (MDs) with 95% confidence intervals (CIs).

RESULTS

Fourteen studies comprising 8451 patients (4797 BEV, 3654 SEV) met the inclusion criteria. There was no significant difference in the risk of severe PPM (OR = 0.61, 95% CI: 0.27-1.37, P = 0.23) or moderate/severe PPM (OR = 0.78, 95% CI: 0.45-1.38, P = 0.40) between BEV and SEV. The mean indexed orifice area did not differ significantly (MD = -0.01, 95% CI: -0.12-0.11, P = 0.93). The risk of new permanent pacemaker implantation was similar between groups (OR = 1.03, 95% CI: 0.67-1.59, P = 0.89). BEV were associated with a near-significant increase in moderate or greater paravalvular leak (OR = 1.39, 95% CI: 1.00-1.93, P = 0.05). Mean transvalvular gradients showed no significant difference (MD = -0.91 mmHg, 95% CI: -3.38-1.57, P = 0.47), though SEV showed a trend toward lower gradients. The certainty of evidence was rated as moderate across most outcomes.

CONCLUSION

In patients with SAA undergoing TAVR, BEV and SEV yield comparable rates of PPM and permanent pacemaker implantation. However, BEV may be associated with a higher risk of moderate or greater paravalvular leak. Valve selection should be individualized, considering patient anatomy and device-specific characteristics to optimize outcomes.