Mx of excessive INR or bleeding on warfarin Rx

see also:

• anticoagulants
• warfarin
• INR
• Western Health guidelines on Mx of bleeding on warfarin (pdf) - only available within WH intranet
• Warfarin Reversal: consensus guidelines, on behalf of the Australasian Society of Thrombosis and Haemostasis (pdf)
• WH Warfarin Reversal Guidelines Quick Guide (pdf) -only available within WH intranet
• WH - Warfarin Reversal Consensus Guidelines full version (pdf) - only available within WH intranet

• each unit rise in INR raises risk of bleeding 3.5-fold
• INR levels > 4.5 in particular are associated with bleeding complications (6x risk cw < 4.5) and should be treated
• ALL patients on warfarin who have a head injury should have a CT brain to exclude haemorrhage.
• Mx should be individualised, with Rx depending on:
  • location & severity of bleeding
  • lab. test results,
  • risk of ceasing anticoagulant Rx
• consider repeat INR 2-4hrly to identify rapid rises
• NB. oral vitamin K is made from IV preparation and just given orally
• if APTT prolonged and potentially life-threatening bleeding then give protamine
• consider insertion of caval filter in pts with recent venous thromboembolism

• (Cruickshank et al Emerg. Med. (2001) 13, 91-7)

• resuscitation
• control bleeding
• cease warfarin
• seek senior advice (eg. haematologist)
• vitamin K 5-10mg i.v.
• FFP 150-300ml (if prothrombinex is unavailable, give 10-15ml/kg FFP)
• Prothrombinex HT (clotting factor concentrate)
  • factor concentrates such as Prothrombinex HT are more effective than FFP at rapidly reversing coagulopathy
  • doses:
    • INR 2.0-3.9: 25 units/kg
    • INR 4.0-5.9: 35 units/kg
    • INR > 5.9: 50 units/kg

• control bleeding
• cease warfarin for 1-2 days
• consider adjusting warfarin dose & look for contributing factors to toxicity
  • INR > 9:
    • vitamin K 2.5-5mg o or 1mg iv
    • consider prothrombinex-VF 25-50 units/kg iv +/- 150-300ml FFP if high risk of bleeding such as
      • age > 65yrs, high ethanol intake, risk of GIT bleed, uncontrolled hypertension, recent trauma, stroke
      • ref: therapeutic guidelines
    • re-check INR 6-12h
  • INR 5-9:
    • if bleeding risk is high, give vitamin K 1-2mg orally or 0.5-1mg slow iv
    • no FFP
    • re-check INR 12-24h
  • INR < 5:
    • no vit K if no bleeding (may consider iv or o vitamin K 0.5-1mg if minor bleeding)
    • re-check INR 12-24h

• mechanical mitral valve
• mechanical aortic valve with arrhythmia or PH thromboembolism

• AF with valvular heart disease, previous stroke or embolism
• cardiomyopathy with heart failure, previous stroke or embolism
• biological heart valves (1st 3months)
• PH multiple PE/DVT
• uncomplicated DVT (<2mths)
• DVT/PE with lab-confirmed hypercoagulable blood
• PH systemic arterial emboli
• mechanical aortic valve without either arrhythmia or PH thromboembolism

• AF without either valvular heart disease, previous stroke or embolism
• cardiomyopathy without either heart failure, previous stroke or embolism
• biological heart valves (EXCEPT 1st 3months)
• uncomplicated DVT (>2mths)
• cerebrovascular disease
• post AMI (mural thrombus prophylaxis)
• vascular surgical prosthetic grafts
• post vascular-stent insertion