THE MANAGEMENT OF THROMBOSIS IN THE ANTIPHOSPHOLIPID-ANTIBODY SYNDROME

Background. The anti phospholipid-anti body syndrome is a thrombophili c disorder in which venous or arterial thrombosis, or both, may occur in patients with antiphospholipid antibodies. The optimal treatment of these patients is unclear. We assessed the efficacy of warfarin, low- dose aspirin, or both in the secondary prevention of thrombosis in pat ients with the syndrome. Methods. One hundred forty-seven patients (12 4 [84 percent] of whom were female) with the antiphospholipid-antibody syndrome and a history of thrombosis were studied retrospectively. Th e syndrome was primary in 62 patients and was associated with systemic lupus erythematosus in 66 patients and lupus-like disease in 19. Each patient's history was reviewed. Results. One hundred one patients (69 percent) had a total of 186 recurrences of thrombosis. The median tim e between the initial thrombosis and the first recurrence was 12 month s (range, 0.5 to 144 months). Treatment with high-intensity warfarin ( producing an international normalized ratio of greater than or equal t o 3) with or without law-dose aspirin (75 mg per day) was significantl y more effective (P<0.001 by the log-rank test) than treatment with lo w-intensity warfarin (producing an international normalized ratio of < 3) with or without low-dose aspirin or treatment with aspirin alone in preventing further thrombotic events (recurrence rates per patient-ye ar, 0.013, 0.23, and 0.18, respectively). The rate of recurrence of th rombosis was highest (1.30 per patient-year) during the first six mont hs after the cessation of warfarin therapy. Complications involving bl eeding occurred in 29 patients during warfarin therapy and were severe in 7 (0.071 and 0.017 occurrence per patient-year, respectively). Con clusions. The risk of recurrent thrombosis in patients with the antiph ospholipid-antibody syndrome is high. Long-term anticoagulation therap y in which the international normalized ratio is maintained at or abov e 3 is advisable in these patients.