Thromboprophylaxis in medical patients

Medical patients represent approximately 25% of VTE events in the general population (1). Regard medical patients as being at increased risk of VTE if they:

• have had or are expected to have significantly reduced mobility for 3 days or more or
• are expected to have ongoing reduced mobility relative to their normal state and have one or more of the risk factors for VTE (1).

The following methods can be used to prevent asymptomatic and symptomatic VTE:

• when the assessment of risk favours use of thromboprophylaxis, UFH (for patients with renal failure), LMWH or fondaparinux should be administered
  • according to a metanalysis published in 2000
    • both LMWH and UFH reduce the rate of DVT and clinical PE by 56-58%
    • there is no difference between the two types of heparin in reducing the risk of DVT, clinical PE or death
    • but LMWH had a lower risk of major bleed (1)
• aspirin is not recommended as the sole pharmacological agent for VTE prophylaxis in medical patients
• mechanical methods are recommended in people in whom bleeding risks outweigh the antithrombotic efficacy of pharmacological prophylaxis (3).
  • anti-embolism stockings (thigh or knee length), foot impulse devices, intermittent pneumatic compression devices (thigh or knee length) (2)
  • mechanical methods are contraindicated in patients at risk of ischaemic skin necrosis, eg those with critical limb ischaemia or severe peripheral neuropathy (2)

In patients with cancer:

• generally are at high risk of VTE and should be considered for prophylaxis with LMWH, UFH or fondaparinux whilst hospitalised
• neither heparin nor vitamin K antagonists are indicated for prolongation of survival in cancer.
• neither warfarin nor heparin should be used to prevent catheter-related deep vein thrombosis in cancer patients (3)

Reference:

• (1) Cayley WE Jr. Preventing deep vein thrombosis in hospital inpatients. BMJ. 2007;335(7611):147-51.
• (2) 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.
• (3) Scottish Intercollegiate Guidelines Network (SIGN) 2010. Prevention and Management of Venous Thromboembolism.