EVOLUTION OF EARLY TIMI-2 FLOW AFTER THROMBOLYSIS FOR ACUTE MYOCARDIAL-INFARCTION

Background Patients with early Thrombolysis in Myocardial Infarction ( TIMI) grade 2 flow after thrombolysis appear to have outcomes similar to thrombolytic failures. To evaluate the origin and evolution of earl y TIMI 2 flow, we examined early and late angiographic and ventriculog raphic data from the Global Utilization of Streptokinase and TPA for O ccluded Arteries (GUSTO-1) angiographic study. Methods and Results Of the 914 patients with both 90-minute and 5- to 7-day catheterizations, 278 patients had TIMI grade 2 flow at 90 minutes. At follow-up, 188 ( 67%) had improved to TIMI grade 3 flow. At 90 minutes, patients with T IMI grade 2 flow had greater infarct vessel narrowing and a significan tly greater incidence of thrombus than patients with TIMI grade 3 flow . At the 5- to 7-day follow-up, patients whose flow had improved from TIMI grade 2 at 90 minutes to grade 3 flow at follow-up had larger-cal iber vessels (minimum luminal diameter, 0.99+/-0.47 versus 0.84+/-0.48 mm; P=.03) and a lower incidence of visible thrombus (26% versus 38%, P=.04) than those with persistent TIMI grade 2 flow. These patients a lso had a higher mean ejection fraction (57.5+/-14.1% versus 52.8+/-12 .9%, P=.02) and better infarct zone wall motion (-2.1+/-1.5 versus -2. 6+/-1.3 SD per chord, P=.01) at the 5- to 7-day follow-up. Patients in whom flow improved from TIMI grade 2 at 90 minutes to TIMI grade 3 by 5 to 7 days had significantly better left ventricular function than p atients with persistent TIMI grade 0, 1, or 2 flow and constituted a g roup whose left ventricular function was intermediate between those wh o had no reperfusion (TIMI grades 0 and 1) and those whose reperfusion was complete (TIMI grade 3). Conclusions These data suggest that inco mplete clot lysis plays a significant role in the pathogenesis of TIMI grade 2 flow. Furthermore, early TIMI grade 2 flow may be sufficient to provide prolonged myocyte viability, which will further recover if flow normalizes.