Intracoronary urokinase in acute myocardial infarction: prevalence of total coronary occlusion during the early hours, effects on myocardial infarct size and left ventricular function, and outcome of residual coronary stenosis.

The effects of intracoronary thrombolysis (ICT) were studied in 88 acute myocardial infarction patients. Total coronary occlusion was observed in 67 of the 88 patients (76.1%) who were evaluated within 6 hours of the onset of symptoms. Among these 67 patients 42 (62.7%) were successfully recanalized by intracoronary urokinase. The recanalization rate was higher in the lesion at the left anterior descending artery, in younger patients (49 years or less) and in patients with a shorter history of pre-infarction angina. Eight of 11 patients (72.7%) with subtotal coronary occlusion and 17 of 35 patients (48.6%) with recanalization after ICT showed spontaneous regression of the residual coronary stenosis at the chronic stage angiography. There was no re-occlusion in the subtotal occlusion group and only 6 cases of re-occlusion (17.1%) in the recanalization group. The majority of re-occlusions progressed from the lesion with 99% residual stenosis and delayed filling. Accordingly the true value of additional percutaneous transluminal coronary angioplasty would be limited to the latter cases. Reduction in infarct size and improvement in left ventricular function were limited to those patients with incomplete or subtotal coronary occlusion and were not seen in cases with total obstruction which was recanalized by ICT.