Antiphospholipid syndrome is probably the most common acquired hypercoagulable state, but information on perioperative management is sparse. Minor alterations in anticoagulant therapy, infection, or a surgical insult may trigger widespread thrombosis. The perioperative course of a 31-yr-old woman with primary anticardiolipin antiphospholipid antibody syndrome requiring a mitral valve replacement is described. Postoperatively, she developed acute global biventricular failure requiring extracorporeal membrane oxygenation support and plasmapheresis. The management of anticoagulation and cardiac surgery in this condition is reviewed.