Angiographic monitoring of reperfusion therapy for acute myocardial infarction. TIMI grade 3 perfusion is the goal.

A ngiography has been used to monitor the effects of thrombolytic therapy on coronary artery anatomy and flow during the early hours of acute of myocardial infarction since the early 1980s.1-3 Several early investigators noted a spectrum of responses of initially occluded coronary arteries to thrombolytic therapy using angiographic assessment.4,5 The Thrombolysis in Myocardial Infarction (TIMI) investigators formalized a set of definitions describing the angiographically monitored response of the infarct artery to thrombolytic therapy6; these definitions have become known as TIMI perfusion grades, and the grading scheme has achieved widespread acceptance as a useful technique for characterizing coronary artery response to thrombolytic therapy. The TIMI perfusion grades classify the responses of infarct-related arteries to thrombolytic therapy into four categories with grade 0 perfusion indicating occlusion of the infarct artery, grade 3 perfusion indicating normal rates of antegrade contrast flow and clearing in the infarct artery (and therefore presumably normal perfusion of myocardium in the infarct bed), and grades 1 and 2 indicating intermediate levels of flow between grades 0 and 3. In the first description of this perfusion-grading scheme, the investigators grouped grades 0 and 1 perfusion together as indicators of failure of reperfusion therapy and grouped grades 2 and 3 together as markers of successful reperfusion therapy. Since the TIMI perfusion-grading scheme (and its dichotomization into successful and failed reperfusion groups) first appeared in 1985, there has been little study of the clinical outcomes associated with the individual TIMI perfusion grades. The dichotomization of the TIMI grading scheme into successful and failed reperfusion groups also has been widely used to characterize the outcomes of many trials involving thrombolytic therapy7-12; furthermore, this dichotomization of infarct artery response to thrombolytic therapy has been used to stratify patients after thrombolytic therapy for evaluation of subsequent percutaneous transluminal coronary angioplasty (PTCA)