Thromboembolism: The formation and/or migration of blood clots in different locations of the venous or arterial vasculature that can occlude or impair the pulmonary or systemic circulation.

<aside> 💡 Every patient needs VTE risk assessment within 24hrs, with weekly review

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• VTE is an umbrella term that includes DVT and PE
• VTE can be defined as blood clots that form within the venous vascular system, dislodge and travel to a distant location.

Demographics

• Incidence increases with age.
• M > F (during reproductive years, F > M).
• Higher risk in African American populations compared with Caucasian populations. Lower risk in Hispanic and Asian populations compared with Caucasian populations.
• Hospitalised patients, patients in nursing homes, long distance travellers.

Aetiology

• Aetiology/pathophysiology: Virchow’s Triad – 3 Factors that predispose an individual to developing venous thrombosis.
  • Venous Endothelial Injury (blood vessel): Attributed to injury and inflammation. Inflammatory or traumatic vessel injuries lead to exposure of subendothelial tissue factor and collagen, which offer a substrate for platelet binding, activation and aggregation; leading to clot formation. e. Surgery, trauma/fracture, central venous catheter, vasculitis, smoking.
  • Venous Stasis (blood flow): Attributed to mostly patient factors. Caused by blood hyper viscosity or increased contact time of coagulation factors with the endothelium. i.e. obesity, bed rest, long distance travel, polycythaemia, valve sites, venodilation, varicose veins.
  • Hypercoagulable State (blood): Attributed to mostly genetic predisposition and hormonal influences Changes in blood coagulation pathway, shifting balance toward coagulation. i.e. Factor V Leiden mutation, pregnancy, oral contraceptives, HRT, active cancer, advancing age, personal or FHx of VTE.

Risk Factors

THROMBOSIS

• Travel
• Hypercoagulable/HRT/Hospitalisation