Thrombolysis in acute myocardial infarction: Analysis of studies comparing accelerated t-PA and streptokinase

Abstract

Objectives - To compare outcomes from accelerated alteplase (recombinant tissue plasminogen activator, t-PA) and streptokinase use in acute myocardial infarction. Methods - Review of available studies identified by Medline and other literature searches that met the criteria of being a prospective, randomised clinical trial enrolling over 1000 patients with acute myocardial infarction. The studies had to contain an intervention arm comprising accelerated infusion t-PA, or an intervention arm comprising streptokinase provided accelerated t-PA that was compared in the same trial. Interventions compared were streptokinase 1.5 million units given over one hour compared with accelerated t-PA infusion, with concomitant use of aspirin and heparin, and main outcome measure of 30 day mortality. Results - Four studies met prespecified criteria, these being the GUSTO I, GUSTO IIb Angioplasty Substudy, GUSTO III, and COBALT trials. There was a total study population of 64,387 patients of whom 20,251 received streptokinase, 19,474 received t-PA, with others receiving different treatment. Pooled data show that accelerated t-PA produces a marginal 30 day mortality compared with streptokinase (6.6% v 7.3%, p = 0.02, Bonferroni adjusted p = 0.12, that is borderline significance, relative risk 0.918, 95% confidence interval 0.854 to 0.986). Any benefit is attributable entirely to patients recruited in the United States in the GUSTO I study. There is an increased incidence of stroke with t-PA. Conclusions - The data do not consistently show a 30 day mortality benefit from using t-PA compared with streptokinase in acute myocardial infarction, but do show increased risk of stroke. Streptokinase can be considered the thrombolytic agent of choice.