Both groups were successfully anticoagulated, and there were no signi cant differences in morbidity or mortality between groups at 7 days, 30 days, or 12 weeks. Postoperative blood loss was statistically higher at 2 hours (238 mL versus 160 mL, p 0.0009), but not at 24 hours (793 mL versus 668 mL, p 0.15). Postoperative reexploration occurred in 6.1% versus 1.9%, but was not statistically signi cant [70]. Anti- coagulation with the direct thrombin inhibitor bivalirudin appears to provide a safe and effective alternative to heparin and protamine reversal, even though it may in- crease the risk of excessive bleeding. In extreme cases, a combination of modi ed ultra ltration, hemodialysis, and administration of recombinant factor VIIa in addition to balanced hemostatic resuscitation with fresh frozen plasma, cryoprecipitate and platelets may be required until the anticoagulant effects of bivalirudin are reversed [68, 71, 72]. Other Alternatives to Heparin Other strategies for anticoagulation treatment of patients with HIT consist of reintroduction of heparin after either the removal of PF4-heparin antibodies (plasmapheresis), administration of intravenous antiplatelet therapy, or use of argatroban. The use of plasmapheresis is generally limited to patients with weakly positive ELISA results requiring urgent cardiac procedures [73 75]. Although each approach appears to be safe and effective, there is insuf cient evidence for a recommendation in the setting of CPB. In a small case series by Welsby and colleagues [74], 11 patients with recent (less than 2 months) diagnosis of HIT received therapeutic plasma volume exchange after in- duction of anesthesia. All patients had a reduction in antibody titers (range of reduction, 50% to 84%). Of these 11 patients, 2 patients had positive HIT antibodies at the 656 Ann Thorac Surg ANTICOAGULATION DURING CARDIOPULMONARY BYPASS 2018;105:650 62 REPORT time of operation. 