Antithrombin replacement and outcome in cardiac surgery

Background and objective: Antithrombin levels during cardiac surgery critically decrease, due to both hemodilution and consumption. This factor prompted the question of whether improved attenuation of hemostatic activation can be achieved by high dose treatment with antithrombin. The aim of this review is to present the currently available pre-clinical and clinical data on the use of antithrombin in cardiac surgery. Methods: Review of the available literature searched using the terms ‘AT’ or ‘Antithrombin’ and ‘Cardiac surgery’ or ‘CPB’ or ‘Cardiopulmonary bypass’. Results: Antithrombin has been proposed in cardiac operations both as purified concentrates and as recombinant human preparations. The main clinical field where antithrombin supplementation is proposed is in case of heparine resistance (failure to achieve adequate anticoagulation following a standard heparin dose). However, other clinical scenarios have been investigated (modulation of inflammatory reaction; pulmonary vasodilation; prevention of thromboembolic complications). Conclusions: Many studies suggest that antithrombin supplementation during and after cardiac surgery may be beneficial to correct abnormally low values. One article found an association between low values of antithrombin activity at the end of the operation and adverse postoperative outcomes. However, a large prospective, randomized trial is still needed to finally set the role of antithrombin supplementation in cardiac surgery.