In the general population risk factors for Venous Thromboembolism (VTE) include:

  • Hypercoagulability (increased coagulability of blood).
  • Haemodynamic changes (alteration in blood flow).
  • Endothelial injury:
    • Trauma or surgery.
    • Vascular instrumentation including venepuncture, intravenous medication or transfusion.

These three risk factor categories are collectively known as “Virchow’s Triad”, which is named after the German physician Rudolf Virchow (1821-1902).

In the general population risk factors for VTE include:

  • Haemodynamic changes:
    • Venous insufficiency (varicose veins) or obstruction.
    • Immobility.
    • Cardiac arrhythmia or atrial/ventricular dysfunction.
  • Endothelial Injury:
    • Trauma or surgery including venepuncture, intravenous medication, transfusion or vascular instrumentation.
    • Atherosclerosis.
  • Hypercoagulability:
    • Following trauma/surgery.
    • Inflammation including sepsis, malignancy or auto-immune disorders.
    • Hormone-related (pregnancy or oestrogen therapies/contraception).
    • Haematological disorders (thrombophilia or myeloproliferative disorders).

In the early stages of recovery following brain injury, risk factors for VTE are particularly influenced by*:

  • Haemodynamic changes:
    • Immobility.
    • Endothelial Injury.
  • Trauma or surgery:
    • Vascular instrumentation including venepuncture, intravenous drugs or transfusion.
  • Hypercoagulability:
    • Following trauma/surgery
    • Inflammation including sepsis.

*In the medically stable patient following brain injury, VTE risk factors are limited to:

  • Haemodynamic changes:
    • Immobility.

In the medically stable brain injured patient who develops sepsis, added risk factors include:

  • Endothelial Injury:
    • Vascular instrumentation including venepuncture, intravenous drugs or transfusion.
  • Hypercoagulability:
    • Inflammation including sepsis.

(* this assumes no co-existing unrelated medical disorders that contribute to VTE risk)