Coronary thrombolysis in man with pro-urokinase: improved efficacy with low dose urokinase.

Single-chain urokinase-type plasminogen activator (scu-PA), was given to 20 patients with acute myocardial infarction first alone (group I; n = 9) and then in combination with an initial bolus injection of 200,000 units of urokinase (group II; n = 11). In group I, scu-PA was administered in a dose of 15 mg up to 60 mg as an infusion over one hour. Complete reperfusion was achieved in 3/9 patients after 50 to 60 min and partial reperfusion in an additional 2 patients. In group II, a bolus injection of urokinase and 48 mg of scu-PA over one hour were given. Reperfusion was achieved in 9/11 patients after a mean of 30 +/- 22 min. Fibrinogen, alpha 2-anti-plasmin and plasminogen levels did not change from baseline in group I. In group II, fibrinogen levels decreased slightly from 272 +/- 84 mg% to 178 +/- 82 mg% (p less than 0.05) after two hours. No bleeding complications were encountered. Reocclusion at 24 hours was evaluated in 18 patients and was not seen. It was concluded that an initial bolus of urokinase improves the efficacy and the rate of thrombolysis by scu-PA.