For patients with acute myocardial infarction, the presence of a patent infarct-related coronary artery may be the most sensitive single predictor of clinical outcome and patient survival. Coronary angiography is the most direct means of assessing reperfusion status; however, availability, cost, and risk are potential concerns. Noninvasive markers are emerging which can reliably and rapidly determine vessel patency, circumventing the need for routine angiography.