Field Implementation Of Remote Ischemic Conditioning In St-Elevation Myocardial Infarction: The First Study

Background: Remote ischemic conditioning (RIC) is a noninvasive therapeutic strategy that uses brief cycles of blood pressure cuff inflation and deflation to protect the myocardium against ischemia-reperfusion injury. We sought to compare major adverse cardiovascular events (MACE) for patients who received RIC before PCI for ST-segmenteelevation myocardial infarction (STEMI) compared with standard care.Methods: We conducted a pre- and postimplementation study. In the preimplementation phase, STEMI patients were taken directly to the PCI lab. After implementation, STEMI patients received 4 cycles of RIC by paramedics or emergency department staff before PCI. The primary outcome was MACE at 90 days. Secondary outcomes included MACE at 30, 60, and 180 days. Inverse probability of treatment weighting using propensity scores estimated causal effects independent from baseline covariables.Results: A total of 1667 (866 preimplementation, 801 post-implementation) patients were included. In the preimplementation phase, 13.4% had MACE at 90 days compared with 11.8% in the postimplementation phase (odds ratio [OR] 0.86, 95% CI 0.62-1.21). There were no significant differences in MACE at 30, 60, and 180 days. Patients presenting with cardiogenic shock or cardiac arrest before PCI were less likely to have MACE at 90 days (42.7% pre vs 27.8% post) if they received RIC before PCI (OR 0.52, 95% CI 0.27-0.98).Conclusions: A strategy of RIC before PCI for STEMI did not reduce 90-day MACE. Future research should explore the impact of RIC before PCI for longer-term clinical outcomes and for patients presenting with cardiogenic shock or cardiac arrest.