Background: Recombinant tissue-type plasminogen activator (rt-PA or alteplase) and anisoylated plasminogen streptokinase activator complex (APSAC or anistreplase) have been demonstrated to limit infarct size significantly and to preserve left ventricular function when injected soon after acute myocardial infarction. However, as yet, the efficacy and safety of these two thrombolytic agents have not been directly compared in one trial; this was the aim of this study.
Methods and results: One hundred eighty-three patients suffering from a first acute myocardial infarction were randomly allocated to either APSAC (30 units over 5 minutes) or single-chain rt-PA (100 mg over a 3-hour period) within 4 hours of the onset of symptoms. Global and regional left ventricular function were assessed from contrast angiography an average of 5.3 +/- 2.3 days after initial therapy. Radionuclide angiography and thallium-201 single-photon emission computerized tomography were performed before hospital discharge. Infarct size was assessed by single-photon emission computerized tomography and expressed in percentage of the total myocardial volume. Ninety patients received APSAC and 93 received rt-PA within a mean period of 172 +/- 52 minutes after the onset of symptoms. The two groups were similar in age, location of the acute myocardial infarction, Killip class, and time of randomization. The patency rate of the infarct-related artery was 72% in the APSAC group and 76% in the rt-PA group (NS). Initial and predischarge left ventricular ejection fraction as well as infarct size were similar in both therapeutic groups (0.50 +/- 0.14 versus 0.52 +/- 0.12 for initial and 0.48 +/- 0.10 versus 0.47 +/- 0.10 for predischarge ejection fraction, 11 +/- 7% versus 9 +/- 7% for infarct size, respectively, for APSAC- and rt-PA-treated patients). Bleeding complications requiring blood transfusion occurred in one APSAC patient and in two rt-PA patients. One patient in the rt-PA group died of a massive intracranial hemorrhage. At the end of the 3-week follow-up period, five APSAC patients (5.5%) and seven rt-PA patients (7.5%) had died.
Conclusions: The early infusion of APSAC or rt-PA in acute myocardial infarction produced a similar patency rate, limitation of infarct size, and preservation of left ventricular systolic function with an equivalent rate of bleeding complications.