Preoperative antithrombin supplementation in cardiac surgery: a randomized controlled trial.
OBJECTIVES
Purified antithrombin supplementation in cardiac surgery has been suggested for the treatment of heparin resistance and the prevention of thromboembolic complications. This study is a randomized controlled trial of preoperative purified antithrombin supplementation, with the primary end point of avoiding low (<58%) postoperative antithrombin activity levels and secondary end points including avoidance of heparin resistance, clinical outcome, and safety end points.


METHODS
Two hundred patients were randomly allocated to the antithrombin group and the control group. Patients in the antithrombin group received a dose of purified antithrombin to reach an antithrombin activity value of 120%, whereas patients in the control group did not receive antithrombin.


RESULTS
The antithrombin activity values were significantly higher in the antithrombin group at all postoperative determinations until discharge. Antithrombin activity levels <58% at admission to the intensive care unit were found in 26.6% of patients in the control group versus none in the antithrombin group (P = .001). Heparin resistance rate was significantly (P = .001) higher in the control group (38.2%) versus the antithrombin group (17%). Patients in the antithrombin group had a significant but clinically irrelevant (8 mL/hour) higher postoperative bleeding, with no differences in transfusion rates. No differences were found for clinical outcomes, and no safety issues were identified.


CONCLUSIONS
Preoperative antithrombin supplementation prevents heparin resistance and avoids excessive postoperative decrease of antithrombin activity.