What is Antiphospholipid Antibody Syndrome (APS)?

From the Guidelines

Antiphospholipid antibody syndrome (APS) is an autoimmune disorder characterized by the presence of antibodies against phospholipids, leading to abnormal blood clotting in arteries and veins, and its diagnosis is dependent on the accurate detection and interpretation of antiphospholipid antibodies (aPL) including lupus anticoagulant (LA), anti-cardiolipin antibodies (aCL), and anti-beta2 glycoprotein I antibodies (aβ2GPI) 1.

Key Characteristics of APS

• APS is a complex condition that requires careful diagnosis and management to prevent thrombotic events and improve patient outcomes.
• The diagnosis of APS is based on the presence of aPL, which can be detected using various laboratory tests, including enzyme-linked immunosorbent assays (ELISAs) 1.
• The management of APS typically involves anticoagulation therapy, with the goal of preventing recurrent thrombotic events and improving quality of life.

Diagnosis and Management of APS

• The diagnosis of APS should be based on a combination of clinical and laboratory criteria, including the presence of aPL and a history of thrombotic events or pregnancy losses 1.
• The management of APS typically involves anticoagulation therapy, with the goal of preventing recurrent thrombotic events and improving quality of life.
• For patients with a history of venous thrombosis, warfarin with a target INR of 2.0-3.0 is recommended indefinitely, although some studies suggest a higher intensity warfarin (INR 3.0-4.0) or addition of antiplatelet therapy like aspirin 81-100mg daily may be needed for arterial thrombosis or recurrent events despite warfarin 1.
• Pregnant women with APS and prior pregnancy losses should receive prophylactic low molecular weight heparin (such as enoxaparin 40mg daily) plus low-dose aspirin throughout pregnancy and for 6 weeks postpartum.
• Regular monitoring of blood counts, liver function, and anticoagulation levels is essential to ensure effective management and minimize the risk of adverse events.

Importance of Accurate Diagnosis and Management

• Accurate diagnosis and management of APS are critical to preventing thrombotic events and improving patient outcomes.
• The use of classification criteria for APS diagnosis should be distinguished from assessment of aPL in clinical care, as classification criteria are strict and meant for participant inclusion in studies and trials, whereas laboratory detection for APS diagnosis in daily practice is broader and meant to diagnose each APS patient to optimize their management 1.

From the Research

Definition and Characteristics of Antiphospholipid Antibody Syndrome (APS)

• Antiphospholipid syndrome (APS) is an acquired autoimmune disorder characterized by thrombosis, pregnancy morbidity, and the presence of antiphospholipid antibodies (aPL) 2, 3, 4, 5, 6.
• APS can cause venous, arterial, and small-vessel thrombosis, as well as pregnancy loss and premature birth 3, 6.
• The syndrome is heterogeneous, and its management should be tailored to individual patients based on their risk assessment, which includes their aPL profile, concomitant autoimmune diseases, and traditional cardiovascular risk factors 2.

Clinical Manifestations of APS

• Thrombotic events in APS can occur in virtually any vascular bed, with cerebral circulation being the most commonly affected arterial territory 2.
• Cardiac valvular disease, renal thrombotic microangiopathy, thrombocytopenia, hemolytic anemia, and cognitive impairment are some of the other clinical symptoms of APS 3.
• Patients with systemic lupus erythematosus (SLE) and those with solely obstetric antiphospholipid syndrome are at higher risk of thrombotic events 3, 6.

Diagnosis and Treatment of APS

• Diagnosis of APS includes the combination of thrombotic events and the presence of aPL, with risk stratification remaining challenging 4, 6.
• Treatment with vitamin K antagonists (VKAs) is the first-line treatment for APS-related venous thrombotic events, while patients with arterial thrombosis should be treated with clopidogrel or VKAs 2, 4, 6.
• Direct oral anticoagulants (DOACs) are not recommended for the treatment of APS, except in selected patients with low-risk venous thromboembolism (VTE) 2, 4, 5, 6.
• Aspirin and heparin therapy are used in the management of obstetric APS, with hydroxychloroquine as a possible supplementary therapy 3, 6.