The role of antithrombin III in the perioperative management of the patient with unstable angina

Background. To evaluate the effectiveness of intraoperative administration of antithrombin III (AT III) to improve anticoagulation and preserve the he mostatic mechanisms during cardiopulmonary bypass (CPB) in patients with un stable angina under heparin treatment. Methods. We divided 22 patients, scheduled for coronary artery bypass graft ing, into two groups. Group A (11 patients) received 3000 International Uni ts (IU) of AT III concentrates plus heparin before aortic cannulation. Grou p B (11 patients) received only heparin. Blood drainage, allogeneic blood t ransfusions, and intraoperative activated coagulation time were recorded. A lso, AT III, thrombin-antithrombin complex (TAT), fragment 1.2 (F 1.2), and D-dimers were measured during the operation and the first postoperative da y. Results. Group A patients had fewer transfusions and had less chest-tube dr ainage. In group A, AT III levels increased after AT III concentrates admin istration and were always higher than in group B. In group B, F 1.2 and TAT increased significantly more after CPB and at the end of operation. Differ ences in D-dimers between the groups were not significant. Conclusions. Intraoperative administration of AT III concentrates allowed a dequate anticoagulation during CPB and attenuated the coagulative cascade a ctivation and the consequent consumptive coagulopathy. (C) 1999 by The Soci ety of Thoracic Surgeons.