NHLBI-Sponsored Randomized Trial of Postconditioning During Primary Percutaneous Coronary Intervention for ST-Elevation Myocardial Infarction.

Rationale: Postconditioning at the time of primary percutaneous coronary intervention (PCI) for ST-segment-elevation myocardial infarction may reduce infarct size and improve myocardial salvage. However, clinical trials have shown inconsistent benefit. Objective: We performed the first National Heart, Lung, and Blood Institute-sponsored trial of postconditioning in the United States using strict enrollment criteria to optimize the early benefits of postconditioning and assess its long-term effects on left ventricular (LV) function. Methods and Results: We randomized 122 ST-segment-elevation myocardial infarction patients to postconditioning (4, 30 seconds PTCA [percutaneous transluminal coronary angioplasty] inflations/deflations)+PCI (n=65) versus routine PCI (n=57). All subjects had an occluded major epicardial artery (thrombolysis in myocardial infarction=0) with ischemic times between 1 and 6 hours with no evidence of preinfarction angina or collateral blood flow. Cardiac magnetic resonance imaging measured at 2 days post-PCI showed no difference between the postconditioning group and control in regards to infarct size (22.5 +/- 14.5 versus 24.0 +/- 18.5 g), myocardial salvage index (30.3 +/- 15.6% versus 31.5 +/- 23.6%), or mean LV ejection fraction. Magnetic resonance imaging at 12 months showed a significant recovery of LV ejection fraction in both groups (61.0 +/- 11.4% and 61.4 +/- 9.1%; P<0.01). Subjects randomized to postconditioning experienced more favorable remodeling over 1 year (LV end-diastolic volume =157 +/- 34 to 150 +/- 38 mL) compared with the control group (157 +/- 40 to 165 +/- 45 mL; P<0.03) and reduced microvascular obstruction (P=0.05) on baseline magnetic resonance imaging and significantly less adverse LV remodeling compared with control subjects with microvascular obstruction (P<0.05). No significant adverse events were associated with the postconditioning protocol and all patients but one (hemorrhagic stroke) survived through 1 year of follow-up. Conclusions: We found no early benefit of postconditioning on infarct size, myocardial salvage index, and LV function compared with routine PCI. However, postconditioning was associated with improved LV remodeling at 1 year of follow-up, especially in subjects with microvascular obstructio