Objectives: The recommended treatment in patients with primary antiphospholipid syndrome (APS) after a thrombotic event is long-term anticoagulation. However, it is still not exactly known how to manage patients who remain stable for years and whose antiphospholipid antibodies (APA) decrease until becoming negative. This study aims to assess the course of the primary APS in a group of patients after anticoagulation therapy is discontinued.
Patients and method: Ten patients with primary APS who had developed deep venous thrombosis in the limbs (9) or in the aorta (1) were included. After a minimum period of 12 months of anticoagulation therapy, this was discontinued if the patients were negative APA during the follow-up in two consecutive measurements.
Results: Six patients (60%) developed persistent negative APA. Four had transient risk factors (2 pregnant, 1 immobilization, 2 oral contraceptives). No new thrombosis episode was observed after a follow-up period of 21 +/- 4.9 months.
Conclusions: Our data suggest that anticoagulation can be discontinued in those patients with primary APS and persistent negative APA, especially if the thrombotic event was venous and occurred in association with a transient risk factor, such as immobilization or pregnancy. Extensive studies are required to confirm these results.