title: Venous thrombosis in the antiphospholipid syndrome.
abstract: The antiphospholipid syndrome is a relatively common acquired cause of venous thrombosis. Up to 20% of cases of deep vein thrombosis, with and without pulmonary embolism, may be associated with antiphospholipid antibodies. These antibodies are typically detected in lupus anticoagulant assays and tests for anticardiolipin antibodies. Most antiphospholipid antibodies are directed against several phospholipid-binding plasma proteins. The most common antigens are beta2-glycoprotein I and prothrombin. Immunoassays using these purified antigens are now available. In addition to being markers for thrombotic risk, antiphospholipid antibodies have been shown to directly contribute to hypercoagulability in animal models and in various in vitro studies. Prevention of recurrent venous thrombosis in patients with the antiphospholipid syndrome requires long-term anticoagulation. The optimal intensity of warfarin therapy is an ongoing issue, but most clinicians currently favor a target INR in the 2.0 to 3.0 range. In certain patients, antiphospholipid antibodies may interfere with determination of the INR, requiring other approaches to monitor and adjust the warfarin dose. Low-dose aspirin is typically recommended for primary prevention of thrombosis in asymptomatic patients with moderate to high levels of antiphospholipid antibodies, although strong supporting data are lacking.
authors.affiliation: Division of Rheumatology, Allergy and Immunology, Department of Medicine, and Thurston Arthritis Research Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7280, USA.
authors.forename: Mary Katherine
authors.initials: MK
authors.lastname: Farmer-Boatwright
authors.forename: Robert A S
authors.initials: RA
authors.lastname: Roubey
mesh_terms: D000818:Animals; D017152:Antibodies, Antiphospholipid / Q000097:blood*; D000925:Anticoagulants / Q000008:administration & dosage / Q000627:therapeutic use*; D016736:Antiphospholipid Syndrome / Q000097:blood / Q000150:complications / Q000188:drug therapy / Q000276:immunology*; D001777:Blood Coagulation / Q000187:drug effects*; D004334:Drug Administration Schedule; D016903:Drug Monitoring; D006801:Humans; D019934:International Normalized Ratio; D011516:Prothrombin / Q000276:immunology; D018570:Risk Assessment; D012307:Risk Factors; D055502:Secondary Prevention; D016896:Treatment Outcome; D020246:Venous Thrombosis / Q000097:blood / Q000188:drug therapy / Q000276:immunology*; D053482:beta 2-Glycoprotein I / Q000276:immunology
chemical_list: D017152:Antibodies, Antiphospholipid; D000925:Anticoagulants; D053482:beta 2-Glycoprotein I; D011516:Prothrombin