Prevention and Treatment of Thrombotic Antiphospholipid Syndrome

Antiphospholipid syndrome (APS) is a clinical syndrome characterized by macro- and/or microvascular thrombosis and pregnancy morbidity, with laboratory criteria including persistently positive lupus anticoagulant and/or anticardiolipin antibody and/or anti-β2 glycoprotein-1 antibody. Patients with antiphospholipid antibodies (aPL) appear to be at increased risk of thrombosis. Primary prophylaxis with aspirin is probably indicated to reduce the risk of a first event in selected patients with positive aPL, though data are limited; aspirin may also be the treatment of choice in selected low-risk patients with prior APS-associated stroke. Generally, secondary prevention of thrombosis involves the administration of anticoagulation as well as, similar to primary prophylaxis, identification and management of modifiable risk factors. Patients with aPL and a history of prior venous thromboembolism without arterial thrombosis are adequately treated with warfarin administered to a target INR of 2.0–3.0. There is a lack of good-quality evidence to support any particular therapeutic strategy for patients with a history of arterial thrombosis. Standard-intensity warfarin (INR 2.0–3.0) is used in many centers, though some centers may choose to use higher-intensity warfarin (INR ≥3.0). All patients with aPL (with/without APS) should engage in regular cardiovascular disease (CVD) screening programs according to national guidelines. Any such patient with an inflammatory rheumatic disease should be managed to minimize inflammatory disease activity, so-called treat-to-target approaches. Hydroxychloroquine is an additional therapy that may facilitate achieving treat-to-targets but may have additional CVD protective properties. Aspirin is frequently added, particularly to patients with “traditional” atherosclerotic risk factors and/or demonstrated atherosclerotic lesions. While a lower threshold for instituting additional CVD risk interventions seems reasonable, currently there is no consensus to support a particular threshold or risk adjustment.