Provoked versus unprovoked pulmonary embolism (PE) or deep vein thrombosis (DVT)

• Provoked DVT or PE occurs in a patient with an antecedent (within 3 months) and transient major clinical risk factor for venous thromboembolism (VTE)
  • for example surgery, trauma, significant immobility (bedbound, unable to walk unaided or likely to spend a substantial proportion of the day in bed or in a chair), pregnancy or puerperium or in a patient who is having hormonal therapy (oral contraceptive or hormone replacement therapy)
• Unprovoked DVT or PE occurs in a patient with:
  • no antecedent major clinical risk factor for VTE who is not having hormonal therapy (oral contraceptive or hormone replacement therapy) or
  • active cancer, thrombophilia or a family history of VTE, because these are underlying risks that remain constant in the patient

Principles of management of DVT/PE

Start the low molecular weight heparin (LMWH), fondaparinux or unfractionated heparin (UFH) as soon as possible and continue it for at least 5 days or until the international normalised ratio (INR) (adjusted by a vitamin K antagonist [VKA]) is 2 or above for at least 24 hours, whichever is longer

• if patient has active cancer and confirmed proximal DVT or PE then offer LMWH, and continue the LMWH for 6 months
  • at 6 months, assess the risks and benefits of continuing anticoagulation
    
    
• offer a VKA to patients with confirmed proximal DVT or PE within 24 hours of diagnosis and continue the VKA for 3 months. At 3 months, assess the risks and benefits of continuing VKA treatment
  
  
• if an unprovoked PE then offer a VKA beyond 3 months, taking into account the patient's risk of venous thromboembolism (VTE) recurrence and whether they are at increased risk of bleeding
  
  
• consider extending the VKA beyond 3 months for patients with unprovoked proximal DVT if their risk of VTE recurrence is high and there is no additional risk of major bleeding

Investigations for cancer if unprovoked DVT or PE

• all patients diagnosed with unprovoked DVT or PE who are not already known to have cancer the following investigations for cancer, should be offered:
  • a physical examination (guided by the patient's full history) and
  • a chest X-ray and
  • blood tests (full blood count, serum calcium and liver function tests) and
  • urinalysis
    
    
• consider further investigations for cancer with an abdomino-pelvic CT scan (and a mammogram for women) in all patients aged over 40 years with a first unprovoked DVT or PE who do not have signs or symptoms of cancer based on initial investigation
  
  
  
  

Reference:

• NICE (June 2012). Venous thromboembolic diseases: the management of venous thromboembolic diseases and the role of thrombophilia testing