Anti-factor Xa monitoring of anticoagulation during cardiopulmonary bypass in a patient with antiphospholipid syndrome

The activated clotting time (ACT) may be an unreliable monitor of coagulation for patients with the antiphospholipid syndrome. We describe a patient with antiphospholipid syndrome in whom adequate anticoagulation during cardiopulmonary bypass was confirmed by monitoring both the ACT and anti-factor Xa levels. The cardiopulmonary bypass was uneventful, and there were no thrombotic or bleeding complications. The use of anti factor Xa levels provided confirmation of adequate anticoagulation (and reversal of anticoagulation) that was not possible using the ACT alone.