Randomised double-blind trial of recombinant pro-urokinase against streptokinase in acute myocardial infarction. PRIMI Trial Study Group.

In a prospective, double-blind, randomised trial, 401 patients with a first acute myocardial infarction were treated within 4 h of onset of symptoms with 80 mg recombinant pro-urokinase or single-chain urokinase plasminogen activator (rscu-PA; proposed INN saruplase) intravenously given as a 20 mg bolus followed by 60 mg infusion for 60 min (198 patients), or 1.5 million IU streptokinase infused over 60 min (203 patients). The first two angiograms were taken at 60 min and at 90 min. Angiography was repeated at 24-36 h. Patency rates at 60 min were 71.8% for rscu-PA and 48.0% for streptokinase (p less than 0.001) and at 90 min they were 71.2% and 63.9%, respectively (p = 0.15). At 24-36 h 6/121 patients treated with rscu-PA and 5/114 patients treated with streptokinase showed reocclusion of the vessel. At the end of the thrombolytic infusion (60 min) fibrinogen concentration had decreased to 0.44 (0.23-1.27) g/l (median, 1st and 3rd quartile) in patients treated with rscu-PA and to 0.17 (0.06-0.27) g/l in patients treated with streptokinase (p less than 0.001). Concentrations of fibrin(ogen) degradation products rose to 96 (24-240) mg/l after rscu-PA and to 240 (192-360) mg/l after streptokinase (p less than 0.001). Bleeding complications were less common in the rscu-PA than in the streptokinase group (p less than 0.01). Thus intravenous rscu-PA led to higher patency rate, earlier reperfusion, less disturbance of haemostasis, and fewer bleeding complications than did intravenous administration of streptokinase.