Anticoagulation in Antiphospholipid Syndrome Should Not Be Stopped
Patients with antiphospholipid syndrome (APS) who have experienced arterial or venous thrombosis require indefinite anticoagulation with a vitamin K antagonist (VKA) and should not discontinue therapy. 1
Standard Treatment Approach
VKA therapy targeting an INR of 2.0-3.0 is the only recommended anticoagulation for APS patients with prior thrombosis and must be continued indefinitely without a predetermined stop date. 1
Direct oral anticoagulants (DOACs/NOACs) are explicitly contraindicated in patients with antiphospholipid antibody syndrome due to inferior efficacy and increased thrombotic risk compared to VKAs. 1
The 2019 European Society of Cardiology guidelines specifically state that moderate-intensity VKA therapy (INR 2.0-3.0) should be continued indefinitely in these patients, as the risk of recurrent thrombosis remains high throughout their lifetime. 1
Why Anticoagulation Cannot Be Stopped
The recurrence rate of thrombosis is highest (1.30 per patient-year) during the first six months after cessation of warfarin therapy, making discontinuation extremely dangerous. 2
APS is classified as a persistent, high-risk thrombophilic condition with an estimated long-term recurrence risk exceeding 8% per year when anticoagulation is stopped. 1
The American College of Chest Physicians guidelines recommend VKA therapy for an indefinite period in patients with antiphospholipid antibody syndrome who have had previous arterial or venous thromboembolism. 1
Rare Exception: Persistently Negative Antibodies
The only potential scenario for considering discontinuation is if antiphospholipid antibodies become persistently negative over time, which occurs in a very small minority of patients. 3, 4
Even in this exceptional circumstance, discontinuation should only be considered if:
- Antibodies remain negative on at least two consecutive measurements 12 weeks apart over a minimum 12-month period 3
- The initial thrombotic event was venous (not arterial) 4
- The event occurred with a transient risk factor (pregnancy, immobilization, oral contraceptives) 4
- The patient had low-risk APS features (single antibody positivity, not triple positive) 3
This approach is based only on small case series and requires close monitoring, as it contradicts standard guideline recommendations. 3, 4
Monitoring Requirements
Patients on indefinite VKA therapy require regular reassessment of drug tolerance, adherence, hepatic and renal function, and bleeding risk at regular intervals (typically every 6-12 months). 1
The target INR should be maintained between 2.0-3.0, as higher intensity anticoagulation (INR 3.0-4.5) does not provide additional benefit and increases bleeding risk. 1
Critical Pitfall to Avoid
Never switch APS patients to DOACs or discontinue anticoagulation based on perceived clinical stability or absence of recent thrombotic events, as the underlying thrombophilic state persists regardless of symptom-free intervals. 1, 5, 6