Maximal endothelial tissue plasminogen activator release is not impaired in patients with acute coronary syndromes before heparin treatment

Procoagulant and fibrinolytic disturbances are described in patients with a cute coronary syndromes (ACS), but whether defective maximal tissue plasmin ogen activator (t-PA) release from the endothelium is also present is still controversial. Previous studies did not take into consideration the contri bution of heparin, which strongly affects fibrinolysis. Accordingly, in thi s study, we measured maximal t-PA release in patients with ACS before, duri ng, and after heparin treatment. Maximal t-PA release was measured by the v enous occlusion test in 38 hospitalized patients with confirmed ACS (18 acu te myocardial infarctions and 20 unstable anginas) before starting heparin, during heparin treatment, and 4 and 12 h after discontinuation. Plasma pla sminogen activator inhibitor type 1 (PAI-1), D-dimer and prothrombin fragme nt F1 + 2 were also measured. Eighteen age-matched subjects with no evidenc e of coronary disease were used as controls. At admission, patients showed significantly higher plasma levels of t-PA, PAI-1, and F1 + 2 than controls . Before heparin, maximal t-PA release was similar in patients and controls . Heparin treatment was associated with a significant increase of plasma t- PA, while it did not affect maximal t-PA release. Coagulative and fibrinoly tic disturbances are present in patients with ACS, but these do not include maximal t-PA release. Among our patients, maximal t-PA release appears sta ble over time and is not affected by heparin treatment. (C) 2001 Lippincott Williams & Wilkins.