Role of DOACs in APS treatment
What are direct oral anticoagulants (DOACs) and what is their role in APS treatment?
DOACs are non-vitamin K antagonist oral anticoagulants that bind directly to specific clotting factors. Dabigatran is a factor IIa inhibitor, whereas rivaroxaban, apixaban, and edoxaban are factor Xa inhibitors. They have a rapid onset of action and relatively short half-life. They should not be used in patients with a CrCl <30 mL/minute. There is limited data on their use in APS patients. One study (Lancet Haematol 2016; 3: e426-e436) reported that rivaroxaban was noninferior to warfarin for secondary prevention of venous thromboembolism in a 6-month trial. A concern is that due to the short half-life of DOACs, an APS patient will be at risk for a clot if they miss one dose. With the limited data available, DOACs are not recommended as the first-line therapy for APS patients. If used, they should not be used in patients with arterial clots.
Pearl : patients on DOACs will have a false-positive LA test. Need to repeat test off DOAC (i.e., hold DOAC for 24–48 hours).