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

Abstract

To evaluate the effectiveness of intraoperative administration of antithrombin III (AT III) to improve anticoagulation and preserve the hemostatic mechanisms during cardiopulmonary bypass (CPB) in patients with unstable angina under heparin treatment. We divided 22 patients, scheduled for coronary artery bypass grafting, into two groups. Group A (11 patients) received 3000 International Units (IU) of AT III concentrates plus heparin before aortic cannulation. Group B (11 patients) received only heparin. Blood drainage, allogeneic blood transfusions, and intraoperative activated coagulation time were recorded. Also, AT III, thrombin-antithrombin complex (TAT), fragment 1.2 (F 1.2), and D-dimers were measured during the operation and the first postoperative day. Group A patients had fewer transfusions and had less chest-tube drainage. In group A, AT III levels increased after AT III concentrates administration 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. Differences in D-dimers between the groups were not significant. Intraoperative administration of AT III concentrates allowed adequate anticoagulation during CPB and attenuated the coagulative cascade activation and the consequent consumptive coagulopathy.