Effects of intracoronary streptokinase in acute myocardial infarction.

Intracoronary streptokinase (SK) was administered to 11 patients with evolving acute transmural myocardial infarction 5.5 +/- 0.4 hours from the onset of symptoms. Ten patients (91%) had total coronary occlusion, and one had subocclusion of the vessel corresponding to the ECG site of infarction. Intracoronary nitroglycerin failed to restore patency of total occlusion in all patients. In 9 of 11 patients (82%), patency was restored or improved with intracoronary SK. Thrombolysis was successful in 8 of 11 patients (73%), and one patient with transient patency developed acute reocclusion. Average time from SK infusion to reperfusion was 24 +/- 7 minutes. Patients with successful thrombolysis had patency initially restored at a dosage of 61,000 +/- 15,000 IU of SK and received a total dosage of 136,000 +/- 17,000 IU. Patency persisted at late study in six of eight patients, and two patients developed late reocclusion. Successful thrombolysis was associated with significant improvement in left ventricular ejection fraction (LVEF) from early to late study, in contrast to deterioration of LVEF in patients with unsuccessful recanalization (p less than 0.001). Systemic fibrinolytic activity occurred in 8 of 11 patients at a mean dosage of 125,000 +/- 15,000 IU of SK and was unassociated with significant bleeding. Significant decrease in hemoglobin concentration in the early hospital phase occurred in patients receiving SK but did not differ from decreases occurring in a matched control population receiving conventional therapy for infarction. Thus intracoronary thrombolysis with SK was successful in the majority of patients during the early phase of evolving transmural infarction, and successful thrombolysis was associated with significant improvement in LVEF. Systemic fibrinolysis occurs in most patients despite small total doses of SK, and the significant decrease in hemoglobin in these patients may be unrelated to SK, since similar changes occurred in a control population receiving conventional therapy.