Venous thromboembolism assessment

VTE risk factors

  • Age >60
  • BMI >30
  • Dehydration
  • Immobility ≥3 days
  • Active cancer
  • Significant comorbidities
  • HRT/oestrogen contraceptives
  • Phlebitis/varicose veins
  • Surgery taking >90 minutes (or >60 minutes on lower limb/pelvis)
  • Pregnancy/<6 weeks post-partum
  • Inflammatory condition
  • Thrombophilia or PMHx / FHx of VTE
  • Obesity
  • Critical care admission

Pharmacological prophylaxis

LMWH/fondaparinux or unfractionated heparin are the most commonly used medications for pharmacological VTE prophylaxis.

  • Pharmacological prophylaxis is used for most patients (unless contraindicated)
  • Assess for contraindications/cautions:
    • Not required
      • Patient taking therapeutic anticoagulant (INR>2 if on warfarin)
    • Procedures
      • Invasive procedure scheduled within next 12 hours
      • Invasive procedure performed within previous 4 hours
    • Significant bleeding risk
      • Active bleeding/stroke
      • Thrombocytopenia (platelets <75×109/L)
      • Bleeding disorders
      • Acute stroke
      • SBP >230mmHg
  • Weigh up the risks and benefits of anticoagulation (discuss with senior if unclear)
  • If the benefits outweigh the risks, determine renal function and weight. Each hospital will have a recommended protocol. Example for patients 50-100kg:
    • eGFR >30 – prophylactic-dose LMWH/fondaparinux (e.g. enoxaparin 40mg S/C OD)
    • eGFR <30 – prophylactic-dose unfractionated heparin (e.g. heparin 5000 units S/C BD)

Mechanical prophylaxis

Thromboembolic deterrent stockings (TEDs) or foot impulse devices/intermittent pneumatic compression devices (IPCs) may be used for mechanical VTE prophylaxis. 

  • Mechanical prophylaxis is used for patients unable to take pharmacological prophylaxis, and in addition to pharmacological prophylaxis in surgical patients
  • Choice depends on individual patient factors and condition/intervention
  • Assess for contraindications:
    • Peripheral arterial disease
    • Fragile skin, e.g. ‘tissue paper skin’, dermatitis, or recent skin graft
    • Severe peripheral oedema
    • Cardiac failure
    • Leg deformity
    • Peripheral neuropathy

To complete

  • ‘I have ensured there are no contraindications, weighed up the risks and benefits, and determined renal function and weight. After obtaining patient consent, I would like to prescribe:
    • LMWH/fondaparinux as per hospital protocol (e.g. enoxaparin 40mg subcutaneously) once every evening
    • And/or thromboembolic deterrent stockings or foot impulse devices/intermittent pneumatic compression devices.’
  • ‘I would reassess the patient’s anticoagulation needs 24 hours after admission.’

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How does heparin work?

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List two types of low molecular weight heparin

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