Prophylaxis versus DVT

There is no current worldwide consensus on which patients should receive thromboprophylaxis. A UK survey suggested that 71% of patients assessed to be at medium or high risk of developing DVT did not receive any form of pharmacological or mechanical Thromboprophylaxis (1).
The following measures could be used to prevent occurrence of DVT:

• general measures
  • mobilisation and leg exercise - immobility increases the risk of DVT about tenfold, hence in patients recently immobilised, early mobilisation and leg exercises should be encouraged
  • adequate hydration - specially in immobilised patients (2)
  • prophylactic measures prior to elective surgery include:
    • stop oral contraceptives 4 weeks before the operation
    • weight reduction if grossly overweight
    • patients rendered immobile during a period of in-patient investigation benefit from a spell of 2-3 week activity before readmission
    • aspirin prior to admission for surgery reduces the risk of developing DVT
• mechanical methods - aimed at increasing mean blood flow velocity in leg veins and reducing venous stasis
  • anti-embolic stockings (AES)
  • intermittent pneumatic compression devices (IPCD)
    • these devices periodically compress the calf and/or thigh muscles of the leg stimulating fibrinolysis as well as blood flow
    • usually used immediately before surgery and are often used along with AES during and after surgery (2)
  • foot impulse devices, also known as foot pumps (FID)
• pharmacological methods
  • the choice of pharmacological agents should be based on local policies and individual patient factors, including clinical condition (such as renal failure) and patient preferences
  • some of the pharmacological agents used are:
    • unfractionated heparin (UFH) and low molecular weight heparins (LMWHs) (usually enoxaparin or dalteparin) (3)
      • given in lower doses than that of treatment of established thromboembolism
      • usually given for at least five days or until discharged from hospital
      • in continued illness and immobility, prolonged prophylaxis may be indicated (2)
    • fondaparinux - a selective factor Xa inhibitor
    • vitamin K antagonists - mainly warfarin, but also acenocoumarol, phenindione, and dicoumarol
    • aspirin
    • newer agents - Dabigatran, Rivaroxaban (1,2,3)

Note:

• assess all patients for risk of bleeding before offering pharmacological VTE prophylaxis. Do not offer pharmacological VTE prophylaxis to patients with any of the risk factors for bleeding, unless the risk of VTE outweighs the risk of bleeding

Reference:

• (1) National Institute for Health and Clinical Excellence (NICE) 2007. Venous thromboembolism:reducing the risk of venous thromboembolism (deep vein thrombosis and pulmonary embolism) in patients admitted to hospital.
• (2) Scottish Intercollegiate Guidelines Network (SIGN) 2010. Prevention and Management of Venous Thromboembolism.
• (3) Cayley WE Jr. Preventing deep vein thrombosis in hospital inpatients. BMJ. 2007;335(7611):147-51.
• (4) Kolbach DN et al. Non-pharmaceutical measures for prevention of post-thrombotic syndrome. Cochrane Database Syst Rev 2004; (1): CD004174