Introduction: Vitamin-K antagonists (VKA) are considered the first-line anticoagulants for thrombotic antiphospholipid syndrome (TAPS), particularly with triple positivity or arterial events. However, thrombotic recurrence remains high despite anticoagulation and other clinical issues may arise. Long-term parenteral anticoagulants may therefore be considered, however little is known about the viability of fondaparinux in this setting.
Materials and methods: We describe the efficacy and safety of long-term fondaparinux for TAPS (>3-months duration) treated at a single centre in the UK. Clinical features and the outcomes of recurrence and bleeding were reviewed using electronic patient records.
Results: 46 patients were identified with history of either venous or arterial TAPS and a total 175 patient-years using fondaparinux (median duration 2.7 years/patient (IQR 1.4-4.8)). 43 (93%) had VKA as first-line anticoagulation with a median duration of 6.5 years (IQR 4.0 - 9.8). All patients received fondaparinux as second-to fourth-line anticoagulation.Thrombosis recurrence occurred in 1 (1%) patient (0.6 events/100-patient years). Major, clinically relevant non-major (CRNM) or minor bleeding occurred in 2 (7%), 5 (10.9%) and 8 (17.4%) patients respectively. Major/CRNM bleeding rates were 1.1 and 2.9 events/100-patient-years. Age >65years was associated with bleeding (p = .047) and concurrent antiplatelets were associated with major/CRNM bleeding (p = .011). Logistic regression showed increasing age was associated with bleeding (OR = 1.097, p = .009).
Conclusions: We suggest that fondaparinux may be used for TAPS when VKA is not appropriate. Thrombotic recurrence was infrequent, and the number of major bleeding events appeared comparable to conventional therapies.
Keywords: Antiphospholipid syndrome; anticoagulants; fondaparinux; hemorrhage; thrombosis.