Comparative Efficacy and Safety of Veno-Arterial Extracorporeal Membrane Oxygenation (VA-ECMO) Versus Impella for Cardiogenic Shock: A Systematic Review and Meta-Analysis

This systematic review and meta-analysis aimed to systematically evaluate the comparative efficacy and safety of Impella and veno-arterial extracorporeal membrane oxygenation (VA-ECMO) in the management of cardiogenic shock (CS). A systematic search of the Cochrane Controlled Register of Trials (CENTRAL), Medical Literature Analysis and Retrieval System Online (MEDLINE), and Scopus was conducted from inception to October 2025 to identify non-randomized and randomized studies comparing Impella and VA-ECMO in adults with CS. The review protocol was registered with the International Prospective Register of Systematic Reviews (PROSPERO) database (CRD420251158340). The primary outcome was short-term mortality. The secondary outcomes included stroke, major bleeding, and limb ischemia. The risk of bias was assessed using the Risk of Bias in Non-randomized Studies of Interventions (ROBINS-I) tool. Pooled risk ratios (RRs) with 95% confidence intervals (CIs) were calculated using a random-effects model with Knapp-Hartung adjustment. Ten non-randomized observational studies involving 5364 patients were included. The overall risk of bias was serious across all studies, primarily due to profound confounding by indication. The meta-analysis revealed no statistically significant difference in the risk of short-term mortality between patients treated with Impella and VA-ECMO (RR, 0.92; 95% CI, 0.76-1.10; p=0.30), although substantial heterogeneity was present (I² = 64.5%). In contrast, Impella use was associated with a significantly lower risk of stroke (RR, 0.52; 95% CI, 0.36-0.75), major bleeding (RR, 0.53; 95% CI, 0.49-0.57), and limb ischemia (RR, 0.55; 95% CI, 0.45-0.68). Based on observational data with a very low certainty of evidence, the use of Impella was not associated with a survival benefit compared to VA-ECMO but was associated with a more favourable safety profile. These findings are limited by confounding factors, and the choice between these devices should be individualized based on the required level of cardiorespiratory support and patient-specific risk factors. Adequately powered randomized controlled trials (RCTs) are required.