Antiphospholipid syndrome and challenges with direct oral anticoagulants.

Direct oral anticoagulants have become the mainstay of the management of venous thromboembolism and atrial fibrillation, and long-term anticoagulation is indicated for those at high risk of further thrombotic events. This includes patients diagnosed with antiphospholipid syndrome, for whom the 'triple positive' laboratory combination of lupus anticoagulant, β2-glycoprotein-1 and anti-cardiolipin antibodies signify those at greatest risk. Data from meta-analysis and randomised control trials have raised the concern that direct oral anticoagulants may be less effective than vitamin K antagonists for the prevention of thrombosis in patients with thrombotic antiphospholipid syndrome, particularly those with the triple positive profile. This article reviews the diagnosis of thrombotic antiphospholipid syndrome, strategies for testing without interruption of anticoagulation, evidence concerning the safety of direct oral anticoagulants in this setting, and the implications for current investigation and management of unprovoked venous thromboembolism.