It is well known that intracoronary thrombolysis during the early period of acute myocardial infarction leads to the limitation of myocardial necrosis, preserves left ventricular function, and improves survivals. The recanalization rate of intracoronary rrokinase infusion into infarct-related coronary artery was known as 62-94 percents in previos studies. The various factors influence the outcome of intracoronary thrombolysis, including total dose of urokinase, time from onsrt of chest pain to thrombolysis. The purpose of this study was to evaluate whether the occlusion site morphology influences recanalization rates of intracoronary thrombolysis.

We evaluated infarct-related coronary artery morphology of 56 acute mycardial infarction patients who performed intracoronary thrombolytic therapy within 6-12 hours after the onset of acute myocardial infarction. Intracoronary urokinase infusion was performed at a rate of 25000 IU/minute. The presence of calcification, collaterals, side branches and the stump site morphologies(thrombus type, pencil type, cutting type) were identified on magnified 35mm cine frames.

Reperfusion was successed in 34 patients and failed in 22 patients. There were no statistically significant difference in the pressure of calcification, collaterals, and side branches between success and failure groups. Intracoronary thrombus was identified in 21 percent of success group, but not in failure group. The reperfusion rates according to stump site morphology were 76% in thrombus type, 58% in cutting type, and 42% in pencil type(p<0.05).

Our study indicates the presence of intracoronary thrombus and the morphology of thrombus type is more effective in intracoronary thrombolysis in acute myocardial infarction. The identification of types of the coronary obstruction will be helpful for the selection of intracoronary thrombolysis in acute myocardial infarction patients. And the results suggest that the difference of stump composition show different stump morphologies.