Objectives: This dose-response study was designed to test two low dose regimens of urokinase administered over a prolonged time period in patients with chronic refractory angina pectoris with respect to effects on clinical symptoms and objective variables of myocardial ischemia.
Background: Patients with severe and chronic refractory angina pectoris in end-stage coronary artery disease represent an increasing clinical problem. Favorable therapeutic effects on myocardial ischemia have been reported for long-term application of low dose urokinase.
Methods: Ninety-eight patients with chronic refractory and end-stage coronary artery disease were randomly assigned to two treatment groups: group A (49 patients) received 50,000 IU and group B (49 patients) 500,000 IU of urokinase as an intravenous bolus infection three times a week over a period of 12 weeks. Variables evaluated were number of weekly anginal events, data from ergometric exercise testing with simultaneous electrocardiographic registration, semiquantitative evaluation of Tc-99m 2-methoxy isobutyl isonitrile (MIBI) scans and rheologic variables.
Results: After 12 weeks of treatment, anginal symptoms (events/week) were reduced significantly in group B by 70% compared with 24% in group A (p < 0.001). Fibrinogen decreased by 3% in group A and by 33% in group B (p < 0.001). Plasma viscosity and red blood cell aggregation were reduced by 6.4% (p < 0.001) and 19.9% (p < 0.001), respectively, in group B. Objective variables of myocardial ischemia were improved significantly in group B only. No cumulation of coronary ischemic events was observed in group B.
Conclusions: Long-term intermittent urokinase therapy in an applied dose of 3 X 500,000 IU/week represents an effective anti-ischemic and antianginal approach for patients with refractory angina pectoris and end-stage coronary artery disease. Apart from rheologic improvement, antithrombotic properties and plaque regression are likely anti-ischemic mechanisms.