Plasminogen activator italian multicenter study (PAIMS): Comparison of intravenous recombinant single-chain human tissue-type plasminogen activator (rt-pa) with intravenous streptokinase in acute myocardial infarction

A single chain preparation of recombinant tissue-type plasminogen activator (rt-PA) was compared with intravenous streptokinase to determine coronary thrombolytic efficacy in patients with acute myocardial infarction <3 h old. Eighty-six patients were randomly selected to receive the intravenous cumulative dose of 100 mg rt-PA and 85 patients to receive 1.5 million units streptokinase. At 240 min after initiation of the thrombolytic therapy noninvasive signs of sustained reperfusion occurred in 79% of patients in both groups (p = NS). Patency of the infarct-related vessel at follow-up angiography was observed in 81% of patients in the rt-PA group and 74% of patients in the streptokinase group (p = NS). At hospital discharge, compared with admission, echocardiographically determined left ventricular ejection fraction increased from 52 ± 11 % to 56 ± 10% (p < 0.01) in the rt-PA group; changes in the streptokinase group (50 ± 9% to 51 ± 11%) were not significant. A nadir value of <1 g/liter fibrinogen plasma level occurred in 6 patients (7%) receiving rt-PA versus 74 patients (87%) receiving streptokinase (p < 0.0001). Plasma levels of fibrin(ogen) degradation products were more than doubled in the streptokinase group (p < 0.01). One patient in the streptokinase group developed a fatal intracranial hemorrhage; five others showed a decline in hemoglobin ≥5 g/dl. Other clinical events in the streptokinase-treated group included allergic reactions (four patients) and intrahospital reinfarction (two patients). None of these events occurred in the rt-PA group. This rt-PA preparation achieves a high rate of stable coronary reperfusion, comparable with that of intravenous streptokinase and is associated with fewer complications and a significant sparing of the hemostatic system.