Warfarin and heparin monitoring in antiphospholipid syndrome

Anticoagulation is cen tral to the man age ment of antiphospholipid syn drome (APS), an acquired thrombo-inflam ma tory disorder characterized by thrombosis (venous, arterial, or microvascular) or pregnancy morbidity, in association with per sis tent antiphospholipid antibodies (aPL; ie, 1 or more of lupus anti co ag u lant [LA], anticardiolipin, anti-beta-2gly co pro tein I, IgG, or IgM antibodies). The main stay of anticoagulation in patients with throm botic APS is war fa rin or an alternative vitamin K antagonist (VKA) and, in certain situations, low-molecular-weight heparin (LMWH) or unfractionated hep a rin (UFH). Accurate assess ment of anticoagulation inten sity under pins opti mal anti co ag u lant dos ing for thrombus treatment or primary/secondary prevention. In patients with APS on warfarin, the international normalized ratio (INR) may not be rep re sen ta tive of anticoagulation inten sity due to an inter ac tion between LA and the throm bo plas tin reagent used in the INR deter mi na tion. In this review, we sum ma rize the use of war fa rin/VKA in patients with APS, along with venous and point-of-care INR mon i tor ing. We also dis cuss the role and mon i tor ing of LMWH/UFH, includ ing in the anti coagulant refractory setting and during pregnancy.