Priorities for Early Revascularization or Introduction of Mechanical Circulatory Support in Patients With Acute Coronary Syndrome Complicated by Cardiogenic Shock - A Systematic Review and Meta-Analysis.

Background: The optimal timing for mechanical circulatory support (MCS) initiation in patients with acute myocardial infarction complicated by cardiogenic shock (CS) is unknown, so in this study we analyzed whether MCS implementation before percutaneous coronary intervention (PCI) is associated with better outcomes compared to after PCI.

Methods and results: We conducted a systematic review and meta-analysis using a random-effects model to account for potential heterogeneity. Risk ratios and 95% confidence intervals were used for dichotomous outcomes. PubMed, Web of Science, and CENTRAL were searched up to April 30, 2023. Certainty of evidence was evaluated according to the Risk of Bias in Non-Randomized Studies of Interventions-I tool. A total of 14 observational studies met the inclusion criteria. We found that venoarterial-extracorporeal membrane oxygenation (VA-ECMO) may have little to no positive effect on short-term survival, but the evidence was very uncertain. Impella use probably increases short-term survival (moderate certainty of evidence), whereas the timing of intra-aortic balloon pump (IABP) insertion improves outcomes (very low certainty of evidence). Pre- and post-PCI MCS implementation may result in little to no difference in bleeding complications or stroke incidence across all device types (low to very low certainty of evidence).

Conclusions: Early Impella implementation before PCI may increase short-term survival, whereas the timing of ECMO or IABP implementation may have little to no effect on outcomes; however, the evidence is very uncertain.