Antiphospholipid Antibody Syndrome

Antiphospholipid antibody syndrome (APS) is a recently defined autoimmune disorder characterized by recurrent vascular thromboses or recurrent pregnancy morbidity; these features are linked to the presence in blood of autoantibodies against negatively charged phospholipids or phospholipid-binding proteins. Thrombosis can occur in any tissue, in veins, arteries, or the microvasculature. Pregnancy morbidity in APS includes miscarriages or premature birth. Criteria that define the major clinical and laboratory features of APS were published in 1999. In patients with antiphospholipid antibodies and prior thrombosis or pregnancy morbidity, there is a high risk of recurrence that persists as long as antiphospholipid antibodies occur in blood. This risk for recurrence of thrombosis or pregnancy morbidity is greatly reduced by preventive anticoagulant therapy. Patients presenting with thrombosis in APS are initially managed in much the same way as are patients with vascular thrombosis owing to other causes. However, in patients with APS, high-intensity anticoagulation is usually needed to prevent recurrences of thrombosis. Thrombosis in APS is often multifactorial, as with non-APS thrombosis. Therefore, in all patients with APS, other reversible risk factors for thrombosis should be sought. The pregnancy outcome of women with APS who have had prior miscarriages is greatly improved by treatment during pregnancy with a combination of heparin and low-dose aspirin.