Abstract 23232: NHLBI-sponsored Trial of Postconditioning During PCI for ST-elevation Myocardial Infarction

IntroductionPostconditioning (PC) is a powerful mechanism to reduce infarct size in animals following ischemia / reperfusion (I/R) injury. However, clinical trials outside the United States have failed to demonstrate a consistent benefit of this technique when performed at the time of primary PCI for STEMI. This may be due in part to patient selection since patients with pre-infarction angina or prolonged ischemic times or TIMI score of 1 were not routinely excluded. To be effective, PC must be performed immediately at the time of reperfusion following a limited ischemic time. We performed the first randomized PC trial in the United States sponsored by the NHLBI with the goal of studying an optimized patient population without confounders of pre-infarction angina or collateral blood flow and with ischemic times between 1 and 6 hours and TIMI flow of 0 who could undergo cardiac MRI measurement of infarct size and myocardial salvage 1-2 days later.Methods and ResultsWe enrolled 101 patients at a single center who presented with their first STEMI due to 100% occlusion of major epicardial artery and met the stringent enrollment criteria. Patients were randomized to PCI + PC (4, 30-sec. cycles of balloon inflation/deflation) versus routine PCI. PC was performed immediately on passage of wire through obstruction when initial reperfusion occurred. No complications were related to the PC procedure and there was no increase in MACE events in the PC group at 30-days of follow-up. PC + PCI did not result in improved LV function or reduction in infarct size or enhance myocardial salvage at similar ischemic times compared to routine PCI.ConclusionIn this highly selective single-center STEMI population with TIMI score of 0 and no evidence of pre-infarction angina or collateral blood flow; the addition of PC prior to PCI did not improve myocardial salvage or reduce infarct size. (NCT 01324453)