Table 5: Management of patients on warfarin undergoing procedures with a high risk of bleeding in the post-operative period. 

For prescribing information on prophylactic and therapeutic doses of Low Molecular Weight Heparin (LMWH) referred to in this table, see here

Day of procedure
Low risk of thrombosis High risk of thrombosis Extremely high risk of thrombosis
If adequate haemostasis, consider prophylactic dose low molecular weight heparin (LMWH) at 6pm (or 4 hours post-op, whichever is later). 
Post-operative anticoagulation day +1 and subsequent days
Low risk of thrombosis High risk of thrombosis Extremely high risk of thrombosis

If bleeding risk remains high, consider prophylactic dose LMWH at 6pm.  When bleeding risk is low (generally day 2 onwards), proceed as below. 

(If bleeding risk remains high in patients at extremely high risk of thrombosis on day 2, the case should be discussed with a cardiologist to allow the approach to bridging to be individualised). 

  • Give prophylactic dose LMWH at 6pm.
  • Only after any epidural has been removed, restart warfarin as soon as safe and practicable (i.e. adequate gut function) with the patient's usual daily dose and monitor INR daily. 
  • Continue prophylactic dose LMWH until INR is ≥2, or patient ready for discharge if sooner. 
  • Give therapeutic dose LMWH at 6pm ensuring 6 hours have elapsed from removal of an epidural if applicable before starting. 
  • Only after any epidural has been removed, restart warfarin as soon as safe and practical (i.e. adequate gut function) with the patient's usual daily dose and monitor INR daily. 
  • Continue LMWH until INR is ≥2.
  • Give therapeutic dose enoxaparin 1mg/kg TWICE DAILY ensuring 6 hours have elapsed from removal of an epidural if applicable.  Do not exceed single dose of 150mg. 
  • Only after any epidural has been removed, restart warfarin as soon as safe and practical (i.e. adequate gut function) with the patient's usual daily dose and monitor INR daily. 
  • Continue enoxaparin until INR is ≥2.
Post Discharge 
Low risk of thrombosis High risk of thrombosis Extremely high risk of thrombosis

Stop prophylactic dose LMWH on discharge, even if INR not within therapeutic range. Arrange INR monitoring as appropriate. 

Continue therapeutic dose LMWH on discharge until INR is ≥2. Arrange INR monitoring as appropriate. 

Continue therapeutic dose enoxaparin 1mg/kg TWICE DAILY on discharge until INR is ≥2. Arrange INR monitoring as appropriate. 

 

Guideline reviewed: August 2025

Page updated: July 2026