Multicenter trial of intravenous Anisoylated Plasminogen Streptokinase Activator Complex (APSAC) in acute myocardial infarction: Effects on infarct size and left, ventricular function

Abstract

Two hundred thirty-one patients with a first acute myocardial infarction were randomly allocated within 5 h after the onset of symptoms either to treatment with anisoylated plasminogen streptokinase activator complex (APSAC), 30 U over 5 min, or to conventional heparin therapy, 5,000 IU in a bolus injection. Heparin was reintroduced in both groups 4 h after initial therapy at a dosage of 500 IU/kg per day. One hundred twelve patients received APSAC and 119 received heparin within a mean period of 188 ± 62 min after the onset of symptoms. Both groups were similar in age, location of the acute myocardial infarction, Killip functional class and time of randomization. Elective coronary arteriography was performed on an average of 4 ± 1.2 days after initial therapy.Follow-up radionuclide angiography and thallium-201 single photon emission computed tomography were performed before hospital discharge. Infarct size was estimated from single photon emission computed tomography and expressed as a percent of total myocardial volume. The patency rate of the infarct-related artery was 77 % in the APSAC group and 36% in the heparin group (p < 0.001). Left ventricular ejection fraction determined from contrast angiography was significantly higher in the APSAC group than in the heparin group. This was true for the entire study group (0.53 ± 0.13 versus 0.47 ± 0.12; p = 0.002) as well as for the subgroups of patients with anterior and inferior wall infarction (0.47 ± 0.13 versus 0.40 ± 0.11; p = 0.04 and 0.56 ± 0.10 versus 0.51 ± 0.11; p = 0.02, respectively). At 3 weeks, the difference remained significant for the anterior myocardial infarction subgroup. A significant 31% reduction in infarct size was found in the APSAC group (33% for the anterior infarction subgroup [p < 0.05] and 16% for the inferior infarction subgroup [p = NS]). A close inverse relation was found between the values of left ventricular ejection fraction and infarct size (r = −0.73, p < 0.01). By the end of a 3 week follow-up period, seven APSAC-treated patients and six heparintreated patients had died.In conclusion, the early infusion of APSAC in acute myocardial infarction produced a high early patency rate, significant limitation of infarct size and significant preservation of left ventricular systolic function, mainly in anterior wall infarction.