Can be considered according to Virchow’s triad:
Venous Stasis
- Prolonged bed rest
- Prolonged air travel (>8 hours)
- Fracture of lower limbs
- Hip or knee replacement
- Spinal cord replacement
- Varicose veins
Hypercoagulability
- Malignancy (particularly metastatic disease)
- Infection (specifically pneumonia, urinary tract infection, and HIV)
- Specific thrombotic conditions:
- Previous venous thrombosis
- Factor V Leiden mutation
- Protein C or S deficiency
- Hyperhomocysteinemia
- Antithrombin III deficiency
- Antiphospholipid antibodies
- Thrombotic thrombocytopenic purpura (TTP)
- High levels of factor VIII
- Nephrotic syndrome
- Inflammatory bowel disease
- Pregnancy
- Drugs:
- Hormone replacement therapy
- Oral contraceptives
- Tamoxifen
- Chemotherapy
- Heart failure or respiratory failure
- Increasing age
- Obesity
Endothelial Injury
- Major surgical procedures
- Trauma
- Prior venous thrombosis
- Venous catheters
- Smoking
- Hypertension