This site is intended for healthcare professionals

Go to /sign-in page

You can view 5 more pages before signing in

Target INRs in different disease managements

Last reviewed dd mmm yyyy. Last edited dd mmm yyyy

Authoring team

  • INR 2-2.5

  • prophylactic treatment for DVT (short-term)

  • INR 2-3

  • prophylactic treatment for hip surgery and surgery for femur fractures (short to medium term)
  • treatment of venous thromboembolism - deep vein thrombosis (DVT) or pulmonary embolism (PE) (1)
    • anticoagulation for 1 month is inadequate treatment after an episode of VTE
    • at least 6 weeks anticoagulation is recommended after calf vein thrombosis and at least 3 months after proximal DVT or PE
    • for patients with temporary risk factors and a low risk of recurrence 3 months of treatment may be sufficient
    • for patients with idiopathic VTE or permanent risk factors at least 6 months anticoagulation is recommended
    • target INR of 2·5 is recommended for long-term oral anticoagulant (VKA) therapy for secondary prevention of VTE
    • target INR of 2·5 is recommended for patients with DVT or PE associated with antiphospholipid syndrome
      • target of 3·5 is also recommended for patients who suffer recurrence of VTE whilst on warfarin with an INR between 2·0 and 3·0
  • cardioversion (1)
    • target INR of 2·5 is recommended for 3 weeks before and 4 weeks after cardioversion
      • to minimise cardioversion cancellations due to low INRs on the day of the procedure a higher target INR, e.g. 3·0, can be used prior to the procedure
  • peripheral arterial thrombosis and grafts
    • antiplatelet drugs remain first line intervention for secondary antithrombotic prophylaxis. If long-term anticoagulation is given to patients at high risk of femoral vein graft failure a target INR of 2·5 is recommended (1)
  • coronary artery thrombosis
    • if oral anticoagulant therapy is prescribed a target INR of 2·5 is recommended (1)
  • systemic embolism after MI
  • mitral stenosis with embolism (long term)
  • atrial fibrillation (long-term) - it may be safer to aim for an INR of 2 in those aged over 75 years (3)
    • risk of stroke is 3 times greater in patients with atrial fibrillation with mitral stenosis than in those without valve disease - based on its apparent effectiveness in non-randomized studies and its effect in non-rheumatic atrial fibrillation, warfarin is usually given to maintain an INR of 2.5 (5)

  • INR 3.0 or more

  • treatment of recurrent DVT, PE (long term)
    • target of 3·5 is also recommended for patients who suffer recurrence of VTE whilst on warfarin with an INR between 2·0 and 3·0
  • prosthetic heart valves (long-term)
    • for patients in whom valve type and location are known specific target INRs are recommended (1)
      • bileaflet valve (aortic) 2·5
      • tilting disk valve (aortic) 3·0
      • bileaflet valve (mitral) 3·0
      • tilting disk (mitral) 3·0
      • caged ball or caged disk (aortic or mitral) 3·5
    • otherwise a target INR of 3·0 is recommended for valves in the aortic position and 3·5 in the mitral position (1)

Notes (1):

  • bioprosthetic valves:
    • long-term warfarin not required in absence of atrial fibrillation
    • oral anticoagulants are not required for valves in the aortic position in patients in sinus rhythm, although many centres anticoagulate patients for 3?6 months after any tissue valve implant
      • patients with bioprostheses in the mitral position should receive oral anticoagulants to achieve an INR of 2.5 for the first 3 months. After 3 months, patients with atrial fibrillation should receive lifelong therapy to achieve an INR of 2.5
      • patients with bioprosthetic valves with a history of systemic embolism and those with intracardiac thrombus should also be anticoagulated to achieve an INR of 2.5
      • patients who do not require oral anticoagulants after the first 3 months may be considered for antiplatelet therapy, e.g. aspirin

  • INR values and risk of haemorrhage versus risk of thromboembolism in treatment of DVT/PE
    • risks of haemorrhage and thromboemboli are minimized at international normalized ratios of 2-3. Ratios that are moderately higher than this therapeutic range appear safe and more effective than subtherapeutic ratios (6)

Reference:


Create an account to add page annotations

Add information to this page that would be handy to have on hand during a consultation, such as a web address or phone number. This information will always be displayed when you visit this page

The content herein is provided for informational purposes and does not replace the need to apply professional clinical judgement when diagnosing or treating any medical condition. A licensed medical practitioner should be consulted for diagnosis and treatment of any and all medical conditions.

Connect

Copyright 2024 Oxbridge Solutions Limited, a subsidiary of OmniaMed Communications Limited. All rights reserved. Any distribution or duplication of the information contained herein is strictly prohibited. Oxbridge Solutions receives funding from advertising but maintains editorial independence.