Venous thromboembolism assessment

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 or they are at usual activity level but it depends on local hospital guidelines
• 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.’

Test your knowledge

How does heparin work?

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How does low molecular weight heparin differ from unfractionated heparin?

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What is the reversal agent for heparin?

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List two types of low molecular weight heparin

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