Comparison of patients with < 60% to > or = 60% diameter narrowing of the myocardial infarct-related artery after thrombolysis. The TIMI Investigators.

The purpose of this study was to analyze angiographic findings, clinical course, and follow-up data on 1,752 patients who underwent protocol cardiac catheterization 18 to 48 hours after enrollment in the Thrombolysis in Myocardial Infarction (TIMI) II pilot and randomized trial: 244 patients (14.0%) had < 60% diameter stenosis in the infarct-related artery and TIMI grade 2 or 3 flow, 1,249 (71.2%) had a narrowing > or = 60% in diameter with TIMI grade 2 or 3 flow, and 259 patients (15%) had TIMI grade 0 or 1 flow (total occlusion). Patients with < 60% narrowing in the infarct-related artery were younger (p < 0.001) and more likely to be current smokers than those with more severe narrowings (p < 0.003). Patients with < 60% diameter stenosis in the infarct-related artery were more likely to have a predischarge radionuclide ejection fraction > 55% (p < 0.001) than were other patient groups. The 1-year mortality rate of patients with < 60% diameter stenosis in the infarct-related artery was 1.6% compared with 4.4% for patients with stenosis > or = 60% and TIMI grade 2 or 3 flow (p = 0.05) and 7.0% for patients with total occlusion (p = 0.004). Patients with stenosis < 60% in the infarct-related artery 18 to 48 hours after thrombolytic therapy have a good prognosis. Infarct artery status predicts predischarge ejection fraction and 1-year mortality.