The role of coronary reperfusion in patients with an acute myocardial infarction (MI) varies with the type of infarction: ST elevation (Q wave) MI (STEMI); or non-ST elevation (non-Q wave) MI (NSTEMI). This topic will review the benefits and potential risks associated with coronary reperfusion after acute MI in older adults. Almost all of the available data come from subset analyses of major trials (in which approximately 10 to 15 percent of patients are over age 75) and nonrandomized retrospective analyses .
ST elevation MI — Early reperfusion with percutaneous coronary intervention (PCI) or fibrinolytic agents improves outcomes in patients with symptoms suggestive of an acute myocardial infarction (MI) who have ST segment elevation, new or presumably new left bundle branch block that obscures ST segment analysis, or a true posterior MI. Primary PCI, usually consisting of angioplasty with stenting, has become a particularly attractive strategy in elderly patients without shock . (See "Primary percutaneous coronary intervention versus fibrinolysis in acute ST elevation myocardial infarction: Clinical trials" and "Fibrinolytic therapy in acute ST elevation myocardial infarction: Initiation of therapy".)
Non-ST elevation MI — Patients with an acute non-ST elevation (non-Q) wave MI (NSTEMI) pose different issues. Fibrinolysis in these patients increases the risk of intracranial hemorrhage and does not appear to improve cardiac outcomes at least in part because the infarct-related artery is not occluded in 60 to 85 percent of cases [3-6].
The role of "primary PCI" performed within two hours in NSTEMI is also uncertain as the major trials that compared this modality to fibrinolysis involved patients who were eligible for fibrinolysis (ie, with an STEMI). (See "Primary percutaneous coronary intervention versus fibrinolysis in acute ST elevation myocardial infarction: Clinical trials".)
Despite this limitation, most patients with an NSTEMI undergo early catheterization and, if appropriate, revascularization within 4 to 48 hours. The 2007 American College of Cardiology/American Heart Association (ACC/AHA) guidelines for the management of a non-ST elevation acute coronary syndrome (ACS) and the 2005 American College of Cardiology/American Heart Association/Society for Cardiovascular Angiography and Interventions (ACC/AHA/SCAI) guidelines on percutaneous coronary intervention (as well as the 2007 focused update) recommended an early invasive strategy to ST segment depression, elevated cardiac enzymes, and a number of other factors in patients with a non-ST elevation ACS [7-9]. (See "Coronary angiography and revascularization for unstable angina or non-ST elevation acute myocardial infarction" and 'Early invasive strategy in NSTEMI' below.)