Thrombosis of veins or arteries should be treated with full-dose oral anticoagulation with warfarin. A Canadian study indicated that using warfarin to keep the target INR at 2–3 provides beneficial results that are equal to that observed with high-dose anticoagulation with an International Normalize Ratio (INR) of 3.1–4.0. A retrospective study in women in whom antiphospholipid antibody syndrome was diagnosed because of pregnancy loss (none of whom had a previous thrombotic event) suggests that treatment with low-dose aspirin provides protection from thrombosis. An ongoing clinical trial in the United States is comparing aspirin with placebo and a study in the UK is comparing aspirin with low-dose warfarin plus aspirin.
Fortunately, this syndrome is rare. Individuals who have lupus and other autoimmune diseases may test posi¬tive for the antiphospholipid antibody syndrome, but the majority usually do not manifest the symptoms, signs, and complications outlined above.