Safety and efficacy of urokinase during elective coronary angioplasty. Eighty-nine of 462 patients were treated with adjunctive urokinase during elective percutaneous transluminal coronary angioplasty (PTCA), 26% for unstable angina, 34% for intracoronary thrombus, 27% for intimal dissection, 10% for abrupt closure, and 3% for saphenous vein graft embolism. The 80 patients treated before abrupt closure (group A) were compared with 167 patients with similar profiles who did not receive urokinase (group B). Procedural success rates were similar. Adverse cardiac events (abrupt closure, myocardial infarction, emergency coronary artery bypass, or death) in group A versus group B occurred in: 1 of 30 (3%) versus 5 of 27 (18.5%) (p = 0.07) with intracoronary thrombus, 5 of 45 (9%) versus 18 of 110 (16.3%) with unstable angina, 1 of 12 (8%) versus 4 of 13 (31%) with unstable angina with intracoronary thrombus, 4 of 33 (12%) versus 14 of 97 (14.4%) with unstable angina without intracoronary thrombus, and 5 of 24 (20.8%) versus 6 of 66 (9%) with intimal dissection. Hemorrhagic complications occurred in 11% of patients who were treated with urokinase versus 9% of patients who were not (p = NS). No difference in blood transfusions existed. Thus urokinase was found to be safe during elective PTCA. In patients with intracoronary thrombus, urokinase appears to decrease the incidence of new adverse cardiac events, whereas in patients with intimal dissection it might have an adverse effect. 