Enalapril related changes in the fibrinolytic system in survivors of myocardial infarction.

Disturbances of the fibrinolytic system have been associated with cardiovascular disease and its risk factors. In the present study the effects of an ACE-inhibitor (enalapril) and a placebo on the fibrinolytic system have been compared. Eighty one survivors of acute myocardial infarction were randomised to treatment with enalapril or placebo. The mass concentrations and activity of tissue plasminogen activator (tPA) and plasminogen activator inhibitor (PAI-1) in plasma were measured three months after the infarction. The enalapril group had a significantly lower level of tPA antigen compared to the placebo-treated group (9.2 and 10.6 respectively). There was no difference between the two groups in any of the other fibrinolytic variables. We conclude that survivors of myocardial infarction treated with enalapril have a significantly lower concentration of tPA antigen than those treated with placebo. This may have a prognostic implication, as lower plasma concentrations of tPA antigen have been associated with better prognosis in patients with established coronary heart disease.