Left Ventricular Unloading Before Percutaneous Coronary Intervention is Associated With Improved Survival in Patients With Acute Myocardial Infarction Complicated by Cardiogenic Shock: A Systematic Review and Meta-Analysis.

BACKGROUND: Left ventricular unloading with Impella may improve survival outcomes in patients with acute myocardial infarction complicated by cardiogenic shock (AMI-CS). However, the optimal timing to initiate left ventricular unloading has yet to be established. Therefore, we conducted a systematic review and meta-analysis to compare survival in patients with AMI-CS who were supported with Impella prior to PCI (pre-PCI) to those in whom support was initiated following PCI (post-PCI). METHODS: All studies that evaluated the impact of pre-PCI versus post-PCI Impella placement in patients with AMI-CS were included. Primary endpoints included in-hospital, 30-day, and 6-month survival rates. RESULTS: We identified five observational studies comparing outcomes in 432 patients with AMI-CS, of which 173 patients were treated with Impella pre-PCI and 259 patients post-PCI. Patients in the pre-PCI group had lower in-hospital mortality compared to patients in the post-PCI group (RR 0.62, 95% CI: 0.50-0.76, I2 = 0%). The lower mortality rate in the pre-PCI group remained evident at 30 days (HR 0.60, 95% CI: 0.47-0.78, I2 = 0%) and at 6 months (HR 0.66, 95% CI: 0.44-0.97, I2 = 0%). There was no difference in the risk of adverse events including reinfarction, stroke, major bleeding, acute ischemic limb, access site bleeding, and hemolysis. CONCLUSIONS: In this meta-analysis of studies evaluating survival among AMI-CS patients with left ventricular unloading initiated pre- versus post-PCI, Impella placement prior to PCI was associated with improved survival.