Efficacy of a New Accelerated Streptokinase Regime in Acute Myocardial Infarction: A Double Blind Randomized Clinical Trial

BACKGROUND: Studies of thrombolysis in acute ST-elevation myocardial infarction (STEMI) have focused on differences in outcome between groups receiving various regimes. Expedited treatment may influence the efficacy of nonfibrin specific thrombolytic agents in restoring early patency of the infarct-related artery (IRA), which is a major determinant of survival after ST-elevation myocardial infarction (STEMI). METHODS: We performed a randomized double blind clinical trial comparing an accelerated infusion (1.5 MU/20 min; group A, n = 200) with the conventional infusion (1.5 MU/60 min; group B, n = 100) of streptokinase (SK) in 300 patients with their first episode of acute STEMI. Demographics, clinical reperfusion rates, angiographic study findings, left ventricular ejection fraction (LVEF), in-hospital morbidity and mortality and one year mortality were compared between two groups. RESULTS: Mean age was 59 ± 12 years (79% male). There were no differences in baseline data between groups. Clinical, electrocardiographic and physiologic reperfusion indices revealed significant faster and higher reperfusion rates and better preserved LVEF at discharge in group A. Sixty-three percent of patients in either group underwent invasive coronary angiography at a mean of 5 days with comparable findings. Atrial fibrillation, malignant ventricular arrhythmias in the second day, in-hospital and late mortalities rates occurred more frequently in group B patients. In multivariate analysis, accelerated SK infusion was the only independent predictor of higher electrocardiographic reperfusion (OR = 3.2, CI: 1.93-5.3, P < 0.001). CONCLUSIONS: The accelerated SK infusion regimen of 1.5 MU in 20 min is safe and well tolerated with significantly faster and higher clinical reperfusion rates, more preserved LV systolic function, less atrial and ventricular sustained arrhythmias, and less in-hospital and 1 year mortality rates in acute STEMI.