Coronary angiopiasty is an effective method to achieve myocardial reperfusion In acute myocardial infarction (AM). We reviewed our experience in 132 patients (pts) who underwent percutaneous transluminal coronary angloplasty (PTCA) of a totally occluded infarct-related artery (IRA) within 24 h after the onset of symptoms (mean delay 10*7 h), in order to identify the predictors of primary success and of major complications. PTCA was successfully performed in 113 patients (86%). Failure without complications OCcurred in 12 patients (8.4O-6); untoward events (death and emergency CABG) occurred in seven patients (5.3%). Pts in the failure group were more likely to have cardiogenic shock (53 vs. 8.8%, P<.0005), longer tlme to reperfusion (1526 vs. 9*6 h, P<.OoOS), lower ejection fraction (EF) (42*16 vs. 54k12%, P<.OWS), multivessel disease (74 vs. 43%, P<.03), and a smaller IRA diameter (2.8k0.6 vs. 3.1 e0.6 mm, k . 0 3 ) . Sex, age, previous bypass surgery, previous thrombolytic treatment, IRA, and infarct location were simllar in both groups. Absence of cardiogenic shock (P<.OOOl), decreasing time to reperfusion (P<.005) and Increasing EF (R.02) were independent predictors of successful PTCA. Presence of cardiogenlc shock (P<.OoOl) and decreasing EF (c.05) were independent predictors of untoward events. Repeat angiography was performed 24 h after the procedure in the success group. Angiographic deterioration (stenosis 2 50K andlor TIMI flow grade 5 1) was present in 18 pts (l6Y0), among whose 5 pts (4.49'0) had reocclusion of the IRA. Pts with early angiographic deterioration were more likely to have a lower IRA diameter (2.8k0.5 vs. 3.1k0.6 mm, R.02). Conclusion: Emergency PTCA is an effective method for establishing reperfuslon in AMI. Pts with high-risk baseline characteristlcs show the highest rate of untoward events, but are the most likely to benefit from aggressive reperfusion therapy.