Table 1

Study inclusion and exclusion criteria
Inclusion criteria People aged 18 years or over with a diagnosis of first unprovoked* proximal** DVT or PE on treatment with anticoagulants
Have completed 3 – 6 months of anticoagulant therapy (target 2–3)
*The episode will be defined as unprovoked as long as there is no history within the previous 3 months of:
major surgery; lower limb trauma e.g. fracture, cast, limping for 3 days; use of the combined oral contraceptive pill or hormone replacement therapy ; pregnancy; significant immobility e.g. confined to bed for 3 days; active cancer.
**Proximal refers to a DVT alone in the trifurcation area, popliteal, superficial femoral, deep femoral, common femoral and iliac veins.
Exclusion criteria Patients under the age of 18 years
Patients with another indication for long term warfarin therapy e.g. Atrial Fibrillation
Patients with a diagnosis of first unprovoked proximal DVT or PE who are no longer on anticoagulation therapy
Patients with a high risk of bleeding as evidenced by any of the following:
• Patients with a previous episode of major bleeding where the cause was not effectively treated
• Known thrombocytopaenia with a platelet count of less than 120 ×109 /L
• Known chronic renal failure with a creatinine of more than 150 μmols/L (1.7 mg/dl) or eGFR less than 30
• Known chronic liver disease with a total bilirubin of more than 25μmols/L (1.5 mg/dl)
• Active peptic ulcer
• Patients requiring antiplatelet therapy (eg Aspirin and/or Clopidogrel)
Patients with a vena cava filter in place
Patients who have had a D–dimer test performed within 2 months of potential enrolment other than for evaluation for suspected recurrent VTE that was not confirmed
Patients whose GP expects their life expectancy to be less than 5 years
Patients unable to attend follow up visits due to geographic inaccessibility
Patients participating in a competing investigation
Patients with known antiphospholipid syndrome
If patients are subsequently found to have antiphospholipid syndrome then they will have to be excluded.
Patients with known inherited protein C and/or protein S or antithrombin deficiency
If patients are subsequently found to have protein C and/or protein S or anithrombin deficiency then they will have to be excluded.
Patients with a diagnosis of active cancer
Patients unwilling to give consent

Tullett et al.

Tullett et al. BMC Cardiovascular Disorders 2013 13:16   doi:10.1186/1471-2261-13-16

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