Three hundred sixty-eight patients were randomly assigned to receive intravenous
streptokinase (IVSK) (n = 191) or standard
therapy (n = 177) to determine the efficacy of IVSK in the treatment of acute
myocardial infarction. The mean
time to treatment was 3.5 hr. At 14 days there were 12 deaths in the treatment group (6.3%) and 17 deaths in the control group (9.6%) (
p = .23). Early mortality was related to
infarct location. Fourteen day mortality for anterior
infarctions was 10.4% for treatment with IVSK and 22.4% for control patients (p = .06) and was similar for IVSK-treated patients with inferior
infarctions, 4.0% vs 1.8% (p = .32). For those randomized under 3 hr, 14 day mortality tends to be lower in treated patients, 5.2% vs 11.5% (
p = .11). There was significant improvement in long-term survival for patients with anterior
infarction; 2 year survival was 81% for IVSK-treated patients and 65% for control patients (p = .05). There was no improvement in survival for patients with
inferior myocardial infarction (p = .27). We conclude that patients with anterior
myocardial infarction have improved survival when treated within the first 6 hr of symptoms. Patients with inferior
infarction do not appear to have improved survival with
thrombolytic therapy. Some of this improvement in survival in patients with anterior
infarction may be due to a higher frequency of revascularization procedures in the treatment group.