Fibrinolysis and hemorrhage after streptokinase in acute myocardial infarct

The purpose of this study is to analyze the relationship between occurrence of hemorrhagic complications, kinetic of fibrinogen degradation-regeneration and the changes of prothrombin time (PT), partial thromboplastin time (PTT), after intravenous administration of Streptokinase (SK), 1.500.000 U., in acute myocardial infarction. 45 selected patients with acute myocardial infarction had pretreatment analysis and serial post-SK measurement of fibrinogen levels, PT, PTT (for 48 hours). Basal fibrinogen levels were 3.2 g/l and displayed significant depression for 18 hours (0.30-0.46 g/l) and normalization after 30 hours from SK infusion. Similar behaviour showed PT and PTT. Minor bleeding was identified in 25 patients. In bleeders mean fibrinogen levels, PT, PTT before and maximum changes after SK were not significantly different compared with non bleeders. We conclude that SK infusion produces important and prolonged changes of fibrinogen levels, PT, PTT; hemorrhagic risk is not related, however, to the extent of lytic state, but probably to pre-existent vascular derangement, predisposing to bleeding complications during fibrinolytic therapy. Therefore we believe to be prudent to delay the infusion of heparin for 12-18 hours after SK administration, when fibrinogen levels are beginning to increase.