Analysis of reported randomized trials of streptokinase therapy for acute myocardial infarction in the 1980s

Trials of intracoronary (IC) and intravenous (IV) streptokinase (SK) therapy for myocardial infarction have shown variable effects on mortality and left ventricular (LV) function. A pooled analysis of 10 randomized trials involving a total of 14,355 patients was performed to look for overall trends in the change in mortality within 6 weeks (group A) and after 6 weeks (group B) of follow-up, and the change in LV function. All 10 trials, 7 with IC and 3 with IV SK, were randomized after 1980. There was a significant reduction in mortality risk in patients in group A treated with IV SK (pooled odds ratio = 0.81, 95% confidence interval = 0.73 to 0.90, p less than 0.001). In contrast, no significant differences in mortality were detected in patients in group B treated with IV SK or in patients in either group treated with IC SK. Two IV SK trials that prospectively stratified patient population according to duration of symptoms showed a greater reduction in mortality with administration of SK therapy within 3 hours of onset of symptoms. Analysis of LV function was performed before, within 96 hours after and 1 to 4 weeks after SK therapy. Only 2 of 7 IC SK trials showed significantly greater improvement in global LV ejection fraction in SK group compared with a control group, both showing improvement in LV function between early and late after treatment. Thus, IV SK therapy significantly reduces short-term risk of death after acute myocardial infarction; 2 trials show a greater reduction in mortality risk with earlier institution of IV SK therapy.