Timing of mechanical circulatory support during primary angioplasty in acute myocardial infarction and cardiogenic shock: Systematic review and meta-analysis

Objectives: We aim to define whether the timing of microaxial left ventricular assist device (IMLVAD) implantation might impact on mortality in acute myocardial infarction (AMI) cardiogenic shock (CS) patients who underwent primary percutaneous coronary intervention (PPCI). Background: Despite the widespread use of PPCI, mortality in patients with AMI and CS remains high. Mechanical circulatory support is a promising bridge to recovery strategy, but evidence on its benefit is still inconclusive and the optimal timing of its utilization remains poorly explored. Methods: We compared clinical outcomes of upstream IMLVAD use before PPCI versus bailout use after PPCI in patients with AMI CS. A systematic review and meta-analysis of studies comparing the two strategies were performed. Effect size was reported as odds ratio (OR) using bailout as reference group and a random effect model was used. Study-level risk estimates were pooled through the generic inverse variance method (random effect model). Results: A total of 11 observational studies were identified, including a pooled population of 6759 AMI-CS patients. Compared with a bailout approach, upstream IMLVAD was associated with significant reduction of 30-day (OR = 0.65; 95% confidence interval [CI] = 0.51-0.82; I-2 = 43%, adjusted OR = 0.54; 95% CI = 0.37-0.59; I-2 = 3%, test for subgroup difference p = 0.30), 6-month (OR = 0.51; 95% CI = 0.27-0.96; I-2 = 66%), and 1-year (OR = 0.56; 95% CI = 0.39-0.79; I-2 = 0%) all-cause mortality. Incidence of access-related bleeding, acute limb ischemia and transfusion outcomes were similar between the two strategies. Conclusion: In patients with AMI-CS undergoing PPCI, upstream IMLVAD was associated with reduced early and midterm all-cause mortality when compared with a bailout strategy.