Antiphospholipid syndrome: Intraoperative and postoperative anticoagulation in cardiac surgery

THE ANTIPHOSPHOLIPID SYNDROME (APLS) is a disorder characterized by arterial and/or venous thrombosis or recurrent fetal loss accompanied by persistent APL antibodies.' APL antibodies are a heterogenous group of antibodies that interact with anionic phospholipid cardiolipin (diphosphatidylglycerol) and other phospholipid-binding protein cofactors, the major one being the serum protein beta(2)-glycoprotein I (also known as apolipoprotein H). Although these patients are at an increased risk of thrombotic complications, they paradoxically have an abnormal profile of coagulation testing exhibiting prolonged activated partial thromboplastin time (aPTT). Patients with APLS are at risk for recurrent vascular occlusive disease (cerebrovascular accident, migraine headaches, and deep venous thrombosis) and other systemic manifestations (myocardial infarction, endocarditis, and pulmonary embolism).(2) They can develop vasculo-occlusive complications before surgery with the reversal of preoperative anticoagulation, intraoperatively because of inadequate anticoagulation during bypass, and postoperatively before adequate anticoagulation is achieved. The risk of perioperative complications is of critical importance during cardiovascular surgical procedures. In two retrospective case series, 8 of 9 patients in one study and 16 of 19 patients in the other developed major complications including cerebrovascular accident, myocardial infarction, and vena caval thrombosis.(3,4) Perioperative diagnosis and management of these patients can be especially challenging. The conduct of anticoagulation for cardiopulmonary bypass in patients having APLS is not readily apparent, especially in those patients showing the phenomenon of a lupus anticoagulant, which prolongs the aPTT but does not protect the patient from thrombosis. Moreover, prolongation of the aPTT complicates monitoring the effects of heparin, Warfarin, and other anti coagulants.(5) There is no consensus regarding intraoperative management of anticoagulation in patients with the APLS. A search of the literature yielded 6 other cases of patients with APL antibodies that detailed the anticoagulation strategy for cardiopulmonary bypass; each case was managed using a different approach. The management of anticoagulation for a woman with APLS undergoing mitral valve repair and a review of the other management strategies is described.