Correlations between fibrinolytic function and acute myocardial infarction.

The diurnal variation of tissue plasminogen activator and plasminogen activator inhibitor--2 important factors in regulation of fibrinolysis--is well established, but its clinical implications are not yet fully understood. Fibrinolytic function was measured in a group of 133 patients less than 45 years of age, 3 months after they presented with myocardial infarction, and they were compared with an equal group of carefully matched control subjects. A sub-sample of 71 patients and 50 control subjects was examined 3 years later. Tissue plasminogen activator inhibitor plasma levels were higher in patients versus control subjects at 3 months and at 3 years after myocardial infarction, with a high degree of correlation between the 2 determinations (r = 0.87). Of all hemostatic parameters studied, only low tissue plasminogen activator activity and increased tissue plasminogen activator inhibitor levels were significantly different between patients with and without recurrent infarction during the 3-year period. In those patients with a second infarction greater than 3 years later, however, tissue plasminogen activator inhibitor concentration was not significantly related to reinfarction.