A Randomized Trial of Intravenous Streptokinase Versus Tissue Plasminogen Activator for the Treatment of Acute Myocardial Infarction: Results Using an Aggressive Approach

Abstract

Seventy‐six patients presenting within 6 hours of the onset of an acute myocardial infarction were randomized to either treatment with 1.5 million units of Streptokinase or 100 mg of recombinant tissue plasminogen activator intravenously. Patients not demonstrating clinical reperfusion within 1 hour were taken emergently for “salvage” angioplasty or coronary bypass surgery. Those patients demonstrating clinical reperfusion underwent early (12 to 72 hours) elective angiography and either elective angioplasty or bypass surgery. The mean time from pain onset to treatment was 149 minutes in the Streptokinase group and 134 minutes in the recombinant tissue plasminogen activator group (P = NS). There were no statistical differences between groups with regard to prior myocardial infarction, infarct location, prior coronary bypass surgery and Killip classification. Clinical reperfusion was demonstrated in 56% of the Streptokinase group and 53% of the recombinant tissue plasminogen activator group (P ‐ NS). Angiographic patency was demonstrated in 70% of the Streptokinase group and 66% of the recombinant tissue plasminogen activator group (P = NS). Left ventricular ejection fraction at discharge was no different: 47% in the Streptokinase group and 43% in the recombinant tissue plasminogen activator group (P = NS). Recurrent ischemic events were found more often in the recombinant tissue plasminogen activator group, 18%, versus the Streptokinase group 3% (P = 0.05). Treatment outcomes did not differ between groups. There was one (3%) death in the Streptokinase group versus two (6%) deaths in the recombinant tissue plasminogen activator group (P = NS). There was a trend toward a greater need for emergent coronary bypass surgery after attempted angioplasty in the recombinant tissue plasminogen activator group, four of 18 patients (22%) versus one of 23 patients (4%) in the Streptokinase group (P = 0.14). In summary, in the setting of acute myocardial infarction treated by thrombolysis, those patients treated with recombinant tissue plasminogen activator experienced significantly more recurrent ischemic events and required emergent coronary bypass surgery more frequently for failed angioplasty compared to those treated with Streptokinase. The results suggest there may be agent specific increases in complications dependent upon the thrombolytic agent of choice when salvage or early coronary angioplasty is used.