A full advisory document can be found on the Healthcare A-Z, Haematology, Policies page:

http://intranet.lothian.scot.nhs.uk/Directory/Haematology/policy/Documents/Venous%20Thromboembolis%20m%20-%20Duration%20of%20anticoagulation.pdf

The following table is taken from the advisory document and offers a summary. Please note that all recommendations should be based on clinical judgement, and a longer course of anticoagulation may be preferred if:

  • the DVT or PE was very large or very symptomatic; or
  • the symptoms of the initial DVT or PE persist; or
  • the patient is not ready (confident) to stop anticoagulant therapy; and
  • the patient does not have a high risk or bleeding

 

Categories of VTE Duration of treatment
First provoked VTE Minimum 3 months (please see caveats in full guidance as patients may require up to 6 months or longer)

First unprovoked VTE*

Low/moderate bleeding risk

High bleeding risk

Minimum of 3 months and then reassess to consider long-term anticoagulation

Indefinite therapy with periodic review

3 months
Isolated distal DVT (calf) 3 months (please see caveats in full guidance as patients may require longer duration of anticoagulation if remaining symptomatic)
Central Venous Catheter (CVC)-related venous thrombosis 3 months
Second provoked VTE 3 months and then assess on case-by-case basis
Second unprovoked VTE Same as for first unprovoked VTE
Cancer-associated VTE Minimum 3 months, then reassess and continue if active cancer or continuing to receive chemotherapy

*Absence of a transient risk factor or active cancer

 

Definition of “transient risk factor”:

Transient risk factors include: surgery, hospitalisation or plaster cast immobilisation, all within the past 3 months; oestrogen therapy (combined contraceptive pill, hormone replacement therapy), pregnancy and puerperium, flight greater than 8 hours, recent leg injuries/trauma (e.g. fracture) or immobilsation (within 6 weeks).

The stronger the provoking risk factor is (e.g. recent major surgery), the lower the expected risk of recurrence after stopping anticoagulant therapy.

Note that temporary immobility (e.g. confined to bed up to 3 days or a flight of less than 6 hours are weak risk factors).