Alterations in the fibrinolytic system components during acute myocardial infarction

The purpose of this study was to evaluate the changes in tissue-plasminogen activator (t-PA), plasminogen activator inhibitor - type I (PAI-I) and D-d imer (DD) antigen plasma levels in acute myocardial infarction (AMI) patien ts after thrombolytic therapy with two different thrombolytic agents, rt-PA or acetyl-streptokinase and to find out any correlation between the plasma t-PA, PAI-I and DD levels with the infarct size as it is estimated from th e peak of serum CPK levels. The plasma antigen levels of t-PA, PAI-I and DD were measured by the enzyme immunoassay method (Stago), in 57 consecutive patients (M = 46, F = 11, mean age 55.6 +/- 8.8 years) and in 25 normal sub jects (M = 18, F = 7, mean age 54.0 +/- 5.5 years). In 47 out of the 57 pat ients who were treated successfully with 100 mg of rt-PA (26 patients) or w ith 1.5 MU 21 of acetyl-streptokinase, as well as in 10 patients who were n ot treated, samples were obtained again 4 and 24 hours after the end of thr ombolytic therapy or admission, respectively. During the acute phase of myo cardial infarction the t-PA, PAI-I and DD antigen plasma levels were signif icantly higher than in healthy people. There were no significant changes in the t-PA, PAI-I and DD plasma levels of the patients who were not treated with a thrombolytic agent. We found a significant elevation of t-PA (p < 0. 001), PAI-I (p < 0.05) and DD (p < 0.001) after 4 hours in comparison with the baseline (at presentation, before therapy). After 24 hours the t-PA and DD plasma levels remained significantly higher (P < 0.001) while the PAI-I plasma levels returned to the pre-therapy levels. There were no significan tly different changes in the t-PA, PAI-I and DD plasma levels of either gro up of patients, treated with rt-PA or acetyl-streptokinase while the t-PA a nd PAI-I levels were positively correlated with infarct size as estimated f rom peak serum CPK levels.