Secondary thromboprophylaxis after a first thromboembolic episode in thrombotic antiphospholipid syndrome

Note: People with thrombotic antiphospholipid syndrome, diagnosed on persistent aPL antibodies and a first thromboembolic episode, require lifelong oral anticoagulation with warfarin (unless contraindicated).

If someone with persistent aPL antibodies (with or without SLE) presents with their first thromboembolic episode (eg deep vein thrombosis [DVT], pulmonary embolism [PE], stroke), the diagnosis of thrombotic antiphospholipid syndrome is confirmed. These people require full anticoagulation for the initial thromboembolic episode, and secondary thromboprophylaxis to prevent recurrence. Secondary thromboprophylaxis involves lifelong oral anticoagulation with warfarin, unless contraindicated.

Management for a first thromboembolic episode (including secondary thromboprophylaxis) is most commonly achieved by:

initial full anticoagulation with heparin—either subcutaneous low molecular weight (LMW) heparin or intravenous unfractionated heparin (UFH), followed by
the addition of oral warfarin, followed by
stopping heparin once warfarin is therapeutic. Patients with thrombotic antiphospholipid syndrome often require a higher target international normalised ratio (INR) (eg 2.5 to 3.5) than people with thromboembolic events unrelated to antiphospholipid syndrome.

Note: Direct-acting oral anticoagulants (DOACs) should not be used in moderate- to high-risk positive aPL-antibody patients.

Direct-acting oral anticoagulants (DOACs) (including apixaban, dabigatran, rivaroxaban) are not appropriate for thromboprophylaxis in people with antiphospholipid syndromeWilliams, 2022. This is especially important for those who have a moderate- to high-risk aPL-antibody profile (determined by a specialist). These people have a higher risk of recurrent thromboembolic events if they are on DOACs rather than warfarin.

DOACs should only be considered in this group if someone is unable to achieve the target INR (eg 2.5 to 3.5) despite good adherence to warfarin, or they have a contraindication to warfarin (eg allergy, significant intolerance).