Factor XII Deficiency and Cardiopulmonary Bypass.

Factor XII deficiency is a laboratory finding in patients who normally do not present with bleeding tendencies. This deficiency is important in the patient undergoing cardiopulmonary bypass because activated clotting times are not helpful in determining proper levels of heparin anticoagulation and its reversal. We present a case of a patient with factor XII deficiency that had coronary artery bypass grafting and cardiopulmonary bypass using heparin for anticoagulation. Cardiopulmonary bypass was successfully carried out by monitoring heparin concentration ensuring adequate heparinization during the procedure. Results from activated clotting time, heparin dose–response, and heparin protamine titration are given. Heparin anticoagulation in patients with factor XII deficiency can be safely carried out with heparin concentration monitoring.