[A study of a systemic fibrinolytic treatment of acute myocardial infarction. The effect of a moderate dose infusion of urokinase].

The clinical efficacy of intravenous fibrinolytic treatment using a moderate dose of urokinase (UK) on acute myocardial infarction (AMI) has not been well evaluated in randomized trials. In order to assess the efficacy of UK, a prospective randomized study was undertaken, aimed mainly at evaluating coronary myocardial blood flow in the infarcted myocardium using Tl-201 myocardial scintigraphy. 166 patients (131 male and 35 female, mean age 61.1 years) with AMI classified in Killip I or II who were admitted to the CCU within 24 hours of the onset of symptoms were divided into two groups; 76 patients treated with UK (UK group) and 90 patients treated with conventional therapy without UK (control group). Intravenous UK 72,000 IU was injected over 10 minutes and UK 528,000 IU was subsequently given by drip infusion over the following 12 (n = 36) or 24 hours (n = 40). There was no significant difference between the two groups with regard to the patients' background. Tl-201 uptake of infarcted myocardium in the UK group (n = 17) significantly increased in the first week compared with that on the day of admission (p less than 0.005) and a further significant increase was observed in the fourth week (p less than 0.05). In the control group (n = 10) Tl-201 uptake did not change in the first week and then increased significantly in the fourth week (p less than 0.05). Coronary angiography and left ventriculography (43 cases in the UK group and 32 cases in the control group) performed in the convalescent stage of AMI showed: 1) similar prevalence of patency of the infarct related artery (UK group: 72.1%, control group: 75.0%), 2) more prominent collateral circulation in the UK group (62.9% vs 41.4%), 3) significantly better perfusion of infarcted myocardium by coronary antegrade flow and/or collateral flow in the UK group (70.0% vs 46.9%, p less than 0.05), 4) a trend towards reduction of severe asynergy in the infarcted regional wall of the left ventricle in the UK group (16.3% vs 34.4%). The mortality rate of patients with first AMI in the UK group (n = 66) was significantly lower than that in the control group (n = 68) (4.5% vs 14.7%, p less than 0.05), and a similar trend was also found in patients with prior infarction (UK: n = 10, 0% vs control: n = 22, 13.6%).(ABSTRACT TRUNCATED AT 400 WORDS)