Thrombolysis for Myocardial Infarction

Background. Coronary patency has been used as a measure of thrombolysis success after acute myocardial infarction. The Thrombolysis in Myocardial Infarction (TIMI) Study Group perfusion grades have gained wide acceptance, with grades 0 (no distal flow) and 1 perfusion (minimal flow) being designated as thrombolysis failures and grades 2 (partial perfusion) and 3 (complete perfusion) as thrombolysis successes. However, the significance of the individual TIMI grades on clinical outcome has not been adequately assessed. Methods and Results. To evaluate the functional significance of TIMI perfusion grades, we compared 1-day coronary patency status with ventriculographic, enzymatic, and ECG indexes of acute myocardial infarction in 298 patients treated with anistreplase or alteplase within 4 hours of myocardial infarction symptom onset. Radionuclide ejection fraction was determined at 1 week and at 1 month. Perfusion grades for the entire study population were distributed as 12% (n=37) grades 0/1, 13% (n=40) grade 2, and 74% (n=221) grade 3. Patency profile did not differ between the two thrombolytic regimens. Further coronary interventions were performed after the 1-day patency determination in 43% of patients (43%, 48%, 42%, respectively, in grades 0/1, 2, and 3 patients). The outcome of grade 2 patients did not differ from grades 0/1 patients in ejection fraction, enzyme peaks, ECG markers, or morbidity index. In contrast, grade 3 patients, compared with grades 0-2 patients, showed 1) a greater global ejection fraction at 1 week (54%