Risk/Benefit Analysis of Intracoronary Thrombolytic Therapy in Evolving Myocardial Infarction.

Intracoronary streptokinase administration during acute myocardial infarction is a time-consuming and potentially dangerous technique. However, it does appear to be beneficial in terms of reduced mortality and improved left ventricular function. We have prospectively studied 258 patients with acute myocardial infarction of whom 180 were subjected to acute cardiac catheterisation and intracoronary streptokinase administration. The remaining 78 either refused the protocol or met exclusion criteria and were studied prospectively as a control group. Patients with anterior myocardial infarction demonstrated a most profound improvement in both mortality and myocardial function with intracoronary thrombolytic therapy. Patients with inferior myocardial infarction demonstrated an improvement in left ventricular function with successful coronary reperfusion, but did not achieve a statistically significant improvement in mortality compared to controls. Time from onset of pain to reperfusion up to 18 h after onset of pain did not affect improvement in left ventricular function or survival. Patients more than 65 years of age did not show a difference in survival when treated with thrombolytic therapy compared with controls of similar age group. However, patients less than 65 years of age treated with intracoronary streptokinase therapy demonstrated a mortality of 4% compared to 18% in similar controls. Two patients may have died as a direct result of intracoronary thrombolytic therapy, but no patients died as a result of bleeding complications. Thus, the most striking results with intracoronary thrombolytic therapy during evolving myocardial infarction are seen in patients with anterior myocardial who are less than 65 years of age. Time from onset of pain to reperfusion and presence of Q waves on initial electrocardiogram do not affect the observed outcome of this intervention. [ABSTRACT FROM PUBLISHER]