Rapid restoration of blood flow in the infarct-related artery (IRA), one of the cornerstones of contemporary treatment of acute myocardial infarction (MI) prevents myocardial necrosis and its consequences. However, due to late presentation or failed fibrinolytic therapy up to one third of patients have persistently occluded IRA after MI.
Recently, the Occluded Artery Trial (OAT) has demonstrated that percutaneous coronary intervention (PCI) with optimal medical therapy does not reduce the frequency of major adverse events compared to optimal medical therapy alone when performed on days 3-28 post MI in stable patients. Assessment of infarct zone viability was not used as an inclusion/exclusion criterion in the main OAT trial.
Several studies confirm that patients with left ventricular systolic dysfunction and preserved myocardial viability (necrosis transmurality\<50% in most segments of the infarct zone) assessed with magnetic resonance imaging benefit from revascularization.
Late opening of the occluded infarct-related artery only in patients with preserved myocardial tissue viability may lead to improvement of left ventricular volumes and function.
