Use of aprotinin during cardiopulmonary bypass in a patient with protein C deficiency

This case study reviews cardiopulmonary bypass (CPB) management in a Protein C deficient patient undergoing reoperation for an atrioventricular (AV) valve replacement with the use of aprotinin. Protein C inhibits factors Va and VIIIa in the coagulation cascade and inactivates tissue plasminogen activator inhibitor, thus maintaining hemostasis. Protein C deficiency can cause hypercoagulability and may result in thrombotic episodes, especially in areas of low blood flow or during activation of the coagulation cascade. A 17-year-old male presented with a functional single ventricle and AV valve regurgitation. The patient had a history of three previous AV valve replacements. Protein C deficiency was first diagnosed after thrombosis of the first valve prosthesis. Other case studies in protein C deficient patients suggested the use of fresh frozen plasma (FFP) before bypass to restore protein C levels, ATIII replacement before heparin administration, and avoidance of aprotinin because of its known competitive inhibition of activated protein C. Two units of FFP were given by anesthesia before the administration of aprotinin, and two units of FFP were added to the pump prime. The full Hammersmith loading dose of aprotinin was administered just before initiation of CPB. The same dose of aprotinin was added to the pump prime just before initiation of CPB. Additional heparin (100 U/kg) was administered every hour during bypass. Activated clotting time tests (ACTs) were performed every 15 min, and thromboelastographs (TEGs) were performed every hour. The patient recovered from surgery without major complications, and there were no perioperative thrombotic events. The patient was discharged on day 41 and is doing well. Postoperative atrial arrhythmias were a contributing factor to his delayed discharge. The use of aprotinin in a protein C deficient patient undergoing open-heart surgery may be safe if protein C levels are restored before administration of aprotinin, and anticoagulation is carefully monitored.