Intracoronary thrombolytic therapy in acute myocardial infarction: A prospective, randomized, controlled trial

Abstract

A prospective, randomized trial was designed to assess the efficacy of intracoronary thrombolytic therapy with streptokinase (STK) in acute myocardial infarction. Sixty-four patients with acute myocardial infarction were randomized within 6 hours of onset of symptoms to 1 of 3 groups. Sixteen patients were treated by conventional means (control group). Nineteen patients underwent coronary arteriography and received corticosteroids and intracoronary and intravenous nitroglycerin (NTG group). Twenty-nine patients received management identical to that of the NTG group, with the addition of intracoronary STK therapy (STK group). Recanalization was demonstrated in 21 of 29 patients (72%) in the STK group. Global and regional ejection fraction (EF) was determined by radionuclide ventriculography before any intervention and 7 to 10 days later. No significant improvement in global EF was achieved in the control and NTG groups. In STK patients as a group, global EF did not increase significantly; however, in patients recanalized with STK, EF improved from 42 ± 17% to 49 ± 16% (p − 0.023). All groups showed wide variability of response. Improvement in global EF of more than 5% was noted in 44% of patients recanalized with STK. When subgrouped on the basis of initial global EF of 45% or less or more than 45%, only patients recanalized with STK with an initial EF of 45% or less had an improved global EF (from 30 ± 10% to 42 ± 10%, p = 0.015). Regional EF of all involved infarct regions was improved only in the STK group (from 34 ± 19% to 42 ± 23%, p = 0.027) and STK-recanalized subgroup (from 33 ±18% to 45 ± 24%, p = 0.003). When only the most involved infarct regions were analyzed, control, NTG and STK groups improved, with patients recanalized with STK showing the greatest degree of improvement. Thus, this trial demonstrates a beneficial effect of thrombolytic therapy in global and, more strikingly, in regional function in patients in whom recanalization with STK is successful, with predominant benefit in those with initially depressed left ventricular function.