SURVIVAL OUTCOMES FOLLOWING VENO-ARTERIAL EXTRACORPOREAL MEMBRANE OXYGENATION FOR ACUTE HEART FAILURE WITH REFRACTORY CARDIOGENIC SHOCK: A CONTEMPORARY SYSTEMATIC REVIEW AND META ANALYSIS

Abstract

Background: Refractory cardiogenic shock (RCS) complicating acute heart failure (AHF) represents a life-threatening condition with historical mortality exceeding 80%. Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) has emerged as a salvage intervention providing temporary mechanical circulatory support, yet its survival benefit remains controversial.

Objectives: To synthesize contemporary evidence quantifying survival outcomes following VA-ECMO deployment in AHF-RCS and identify prognostic determinants influencing clinical outcomes.

Methods: We conducted a systematic review following PRISMA guidelines, searching PubMed, Embase, and Cochrane databases from January 2018 through April 2024. Eligible studies reported short-term (ECMO weaning) and intermediate-term (hospital discharge or 30-day) survival in adults with AHF-RCS managed with VA-ECMO. Random-effects meta-analysis generated pooled proportions with 95% confidence intervals (CI). Heterogeneity was quantified using I² statistics. Subgroup analyses stratified outcomes by shock etiology.

Results: Forty-three studies (one randomized controlled trial, 42 observational studies; n=9,842 patients) met inclusion criteria. Pooled successful weaning from VA-ECMO occurred in 65.2% (95% CI: 60.1-70.0%; I²=78%). However, survival to hospital discharge or 30 days was achieved in only 38.5% (95% CI: 34.2-43.0%; I²=82%). Etiology-specific survival varied substantially: myocarditis 58.1% (95% CI: 49.5-66.3%), acute myocardial infarction 35.8% (95% CI: 30.1-41.9%), post-cardiotomy shock 33.5% (95% CI: 27.0-40.6%), and out-of-hospital cardiac arrest 27.3% (95% CI: 21.0-34.5%). The EOLE randomized trial demonstrated non-significant survival improvement with VA-ECMO versus medical therapy (31% vs. 22%; p=0.21). Major complications included bleeding requiring intervention (41.2%), limb ischemia (12.4%), and stroke (9.1%).

Conclusions: VA-ECMO effectively stabilizes the majority of patients with AHF-RCS, enabling successful weaning in approximately two-thirds. However, survival to discharge remains modest at 38.5%, with a substantial 27-percentage-point gap between weaning and survival. Outcomes are highly etiology-dependent, with myocarditis demonstrating the most favorable prognosis. The considerable complication burden and marginal survival benefit in unselected populations underscore the critical importance of rigorous patient selection, etiology-based risk stratification, and integration within comprehensive mechanical support algorithms. Future research must prioritize randomized trials in specific patient subgroups and strategies to mitigate life-threatening complications.