What factors may increase the risk of thrombosis in a patient with Antiphospholipid Antibodies?
At the time of thrombosis, over 50% of APS patients will have one or more of the following thrombosis risk factors:
- • Antibody characteristics.
- – Triple positives (LA, aCL, anti-β2GPI abs).
- – IgG with anti-β2GPI reactivity especially against the first domain.
- – High titers of aPL antibodies (>40 units).
- – LA.
- • Increased tissue factor release.
- – Infection.
- – Surgery.
- • Abnormal endothelium.
- – Active vasculitis/inflammatory disease (SLE).
- – Atherosclerosis and risk factors (diabetes, hyperlipidemia, high blood pressure).
- – Catheterization for arteriography/intravenous (IV) access.
- • Prothrombotic risk factors.
- – Smoking.
- – Oral contraceptives.
- – Pregnancy.
- – Homocystinemia (MTHFR gene mutation A1298C).
- – Hereditary hypercoagulable disorders (rule out in all patients with a family history of venous thrombosis).
- – Factor V Leiden (activated protein C resistance).
- – Protein C or S deficiency.
- – Prothrombin gene mutation (G20210A).
- – Antithrombotin III deficiency.
- – History of previous thrombosis or fetal loss.
- – Use of cyclooxygenase-2 specific inhibitors (controversial).
