Changes in the hemostatic mechanism after myocardial infarction.

Plasma coagulation factors, adenosine diphosphate-induced platelet aggregation, and fibrinolytic activity were studied in male survivors of myocardial infarction and in healthy normal men. Infarction survivors had significant elevations of factors VIII and X and of adenosine diphosphate-induced platelet aggregation. The fibrinolytic system was altered toward reduced plasminogen activation, increased antiurokinase activity, and elevated antiplasmin activity. These findings suggest that some men with prior myocardial infarction have a heightened tendency to thrombogenesis. This tendency may represent a response to previous cardiac insult or may contribute to its pathogenesis.