Early Versus Bail-Out Left Ventricular Unloading During Venoarterial Extracorporeal Membrane Oxygenation: A Systematic Review And Meta-Analysis

Left ventricular (LV) unloading has demonstrated favorable outcomes in patients undergoing venoarterial extracorporeal membrane oxygenation (VA-ECMO). However, the optimal timing for LV unloading during VA-ECMO remains controversial. PubMed, Embase, and Cochrane were searched for studies comparing early versus bail-out LV unloading in patients undergoing VA-ECMO. We computed mean differences (MD) for continuous outcomes and risk ratios (RR) for binary outcomes, with 95% confidence intervals (95%CIs). Heterogeneity was assessed using I² statistics. Statistical analyses were performed using R version 4.2.3. Six studies comprising 1,556 participants were included in the meta-analysis, of whom 936 (60%) were referred to early LV unloading. There were no significant differences between groups in weaning from VA-ECMO (MD 1.07; 95% CI 0.86 - 1.33; p = 0.55; I² = 26%), in-hospital mortality (RR 0.95; 95% CI 0.86 - 1.05; p = 0.28; I² = 0%), 30-day mortality (RR 0.75; 95% CI 0.52 - 1.10; p = 0.14; I² = 64%), or duration of VA-ECMO (MD 0.37; 95% CI –1.57 - 2.32; p = 0.71; I² = 20%). Sepsis (RR 0.84; 95% CI 0.63 - 1.11; p = 0.22; I² = 0%), stroke (RR 0.90; 95% CI 0.52 - 1.56; p = 0.70; I² = 48%), and bridge to heart transplantation or left ventricular assist device (RR 1.20; 95% CI 0.90 - 1.62; p = 0.22; I² = 0%) also did not differ significantly between the groups. In patients undergoing VA-ECMO, early LV unloading was not associated with improved efficacy and safety outcomes when compared to the bail-out strategy for LV unloading.