Invasive reperfusion study II. Multicentre European randomized trial of anistreplase vs streptokinase in acute myocardial infarction

IRS II (Invasive reperfusion study II) was a multicentre randomizedtrial comparing the efficacy of a 2–5-min 30 U anistreplaseintravenous injection with a 1 500 000 U 60-min streptokinase(SK) intravenous infusion in acute myocardial infarction. 116patients were randomized within 6 h of onset of symptoms. Earlycoronary patency was assessable in 107 patients by coronaryangiogram performed 102 min after thrombolytic treatment (range:30–297 min) in the anistreplase group and 93 min (range:22–330 min) in the SK group. The early coronary patencyrate was significantly higher in the anistreplase group thanin the SK group: respectively, 70% (38/54) and 51% (27/53),P<0.05. Fifty patients had assessable coronary angiogramsat 90 min and 24 h. The 24-h patency rate was 92.3% (24/26)in the anistreplase group vs 87.5% (21/24) in the SK group.No early reocclusion occurred in the anistreplase group vs 15.4%(2/13) in the SK group (NS). Fibrinogen fell to 13.2 ±19.8%on anistreplase vs 9.4 ±10.3% on SK (NS). Bleeding complicationsoccurred in 12% (7/58) of treated patients in the anistreplasegroup vs 20.7% (13/58) in the SK group (NS). Two cerebrovascularaccidents occurred after thrombolytic treatment with anistreplase(3.4%) vs one after SK (1.7%) (NS). Thus, anistreplase is moreeffective than intravenous SK and easier to administer.