Can be considered according to Virchow’s triad:
Venous Stasis
  • Prolonged bed rest 1
  • Prolonged air travel (>8 hours) 1
  • Fracture of lower limbs 1
  • Hip or knee replacement 1
  • Spinal cord replacement 1
  • Varicose veins 1
Hypercoagulability
  • Malignancy (particularly metastatic disease 1)
  • Infection 1(specifically pneumonia, urinary tract infection, and HIV)
  • Specific thrombotic conditions 1:
    • Previous venous thrombosis 1
    • 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 1
  • Inflammatory bowel disease 1
  • Pregnancy 1
  • Drugs:
    • Hormone replacement therapy 1
    • Oral contraceptives 1
    • Tamoxifen 1
    • Chemotherapy 1
  • Heart failure or respiratory failure 1
  • Increasing age 1
  • Obesity 1
Endothelial Injury
  • Major surgical procedures 1
  • Trauma 1
  • Prior venous thrombosis
  • Venous catheters 1
  • Smoking 1
  • Hypertension 1