Balloon-Expandable Versus Self-Expanding Transcatheter Aortic Valve Implantation in Patients With Small Aortic Annulus: A Meta-Analysis.

Although transcatheter aortic valve implantation (TAVI) is considered a superior option to surgery in patients with small aortic annulus (SAA), it is not clear which type of transcatheter heart valve (THV) has better results in terms of echocardiographic hemodynamics and clinical outcomes. A random-effects meta-analysis was performed comparing balloon-expandable valves (BEVs) and self-expanding valves (SEVs) in patients with SAA who underwent TAVI regarding their impact on hemodynamic and clinical outcomes at short- and midterm follow-up. Relative risk (RR) and mean difference (MD) with 95% confidence interval (95% CI) were measured for the outcomes, as appropriate. Subgroup analyses were performed based on the generation type of devices and study designs. A total of 16 articles comprising 1 randomized trial, 3 propensity-matched studies, and 12 observational studies including 4,341 patients (1,967 in BEV and 2,374 in the SEV group) with SAA were included. The implantation of BEVs correlated with a lower indexed effective orifice area (MD -0.19 [-0.25 to -0.13]) and higher transvalvular mean pressure gradient (MD 3.91, 95% CI 2.96 to 4.87). Compared with SEVs, BEVs had increased risk of prosthesis-patient mismatch (PPM; RR 2.09, 95% CI 1.79 to 2.45) and severe PPM (RR 2.16, 95% CI 1.48 to 3.15). However, BEV had lower moderate and severe paravalvular leak (RR 0.45, 95% CI 0.29 to 0.69), risk of stroke (RR 0.57, 95% CI 0.42 to 0.76), and permanent pacemaker implantation (RR 0.63, 95% CI 0.44 to 0.91). The 1-year all-cause mortality (RR 1.13, 95% CI 0.86 to 1.49) and cardiac-related mortality (RR 1.53, 95% CI 0.24 to 9.81) were not different between the 2 groups. In conclusion, SEVs were associated with larger indexed effective orifice area and lower PPM but higher paravalvular leak. In contrast, patients with SEVs were more likely to develop stroke and required permanent pacemaker implantation. Both THVs did not show difference in terms of early and midterm all-cause and cardiac mortality. Because both types of THVs show similar results regarding mortality data, hemodynamics should be among the factors considered in decision making for patients with SAA who underwent TAVI.