Duration of anticoagulation therapy

Borders Ref Help Toolkit
NHS Borders

Please note changes in coagulation testing – in particular that there can be occasional spuriously high INR readings in patients with antiphospholipid syndrome. 

Many patients will not need referral following a DVT or PE: please see ‘Who not to refer’ for details of anticoagulation duration in uncomplicated cases.

Management of patients with pulmonary embolism should be discussed with Respiratory Medicine to determine the need for assessment re thromboembolic pulmonary hypertension.

In cases of single massive PE or extensive proximal DVT extending into the pelvis (especially if unprovoked), discuss with the hospital physician managing the patient, or consider referral to Haematology before discontinuing anticoagulation.

Cancer-related thrombosis: anticoagulation must be continued in liaison with the patient’s oncologist whilst active cancer is present.

Who to refer, who not to refer, how to refer

Who to refer:

  • Patients with a significant contraindication to anticoagulation.
  • Patients on warfarin with persistent sub- or supra-therapeutic INR, except when due to poor compliance or alcohol abuse. Please also refer to Difficulty in Warfarinisation guideline .
  • Patients with major haemorrhage on anticoagulation.
  • Patients with DVT/PE where there is clinical doubt about duration of anticoagulation after consulting guidelines documented below, and/or the hospital physician with primary responsibility for the patient

Who not to refer:

  • Single provoked DVT/PE – anticoagulate for at least 3 months
  • Two spontaneous or unprovoked DVT/PE: anticoagulate long-term and consider if any indication for thrombophilia testing (family history, recurrent miscarriages, recurrent unprovoked VTE)

All patients should be evaluated for continuing clinical risk factors before stopping anticoagulation.

How to refer:

SCI Gateway to Department of Haematology BGH

Editorial Information

Last reviewed: 17/01/2025

Next review date: 17/01/2027

Author(s): Charlotte Robertson.