Objective: To study the changes of the endothelial tissue plasminogen activator (tPA) reserve capacity in patients with acute coronary syndromes (ACS).
Methods: Veinous blood was sampled for determination of markers of the fibrinolytic system and hypercoagulability at admission and on the 10th day in patients with acute coronary syndrome (ACS), including acute myocardial infarction (AMI) in 15 and unstable angina pectoris (UAP) in 20. An occlusion test to determine the maximal endothelial tPA release was performed in order to evaluate the endothelial tPA reserve capacity. 20 patients with stable angina pectoris (SAP) and 12 normal subjects served as control.
Results: Patients with ACS had higher levels of tPA mass concentration, PAI-1 activity, D-dimers mass concentration and TAT mass concentration at admission and on the 10th day as compared with those in SAP and normal subjects. Maximal endothelial tPA release was initially reduced to (2.2 +/- 0.8) microg/L (P < 0.01, vs patients with SAP), but the levels recovered on the 10th day of follow-up to (4.5 +/- 1.2) microg/L (P > 0.05, vs patients with SAP).
Conclusion: Endothelial tPA reserve capacity is reduced only during the acute phase and becomes normalized during follow-up. The alterations of plasma markers of systemic fibrinolysis persist longer in patients with ACS. The results demonstrated that the intravascular thrombus formation may relate more to the disturbance of endothelial fibrinolysis than to markers of the systemic fibrinolytic system. It is very important to correct the disturbances of endothelial fibrinolysis during the acute phase of ACS.