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Medical Review - Articles by Medical Review Staff

Prepared May 3, 2005

By Howell Johnson, M.D., Associate Medical Director

Management of Anticoagulation Before and After Elective Surgery

The most common indications for warfarin therapy are atrial fibrillation, mechanical heart valves, and venous thrombosis.

Surgery in patients taking warfarin increases risk of bleeding. On the other hand, stopping warfarin raises concerns about thrombotic complications.

The perioperative use of intravenous heparin is not indicated in most patients on long-term anticoagulant therapy. The absolute risk of thromboembolism associated with a few days of perioperative sub therapeutic anticoagulation is generally very low, and the risk of bleeding associated with postop intravenous heparin is relatively high.

If the international normalized ration (INR) is between 2.0 and 3.0, four scheduled doses of warfarin should be withheld to allow the INR to fall spontaneously to 1.5 or less before surgery. Warfarin should be withheld longer if the INR is above 3.0 or if the level to be achieved is less than 1.3. If necessary, vitamin K, 1 mg p.o. or 0.5 mg IV, may be given the day before surgery if there is inadequate reversal of the INR.

No Prior Days Approved Before Surgery for Low Risk for Thromboembolism Conditions:

  1. Dental extraction may safely be performed while maintaining anticoagulation. The mouth should be rinsed with an antifibrinolytic agent such as 500 mg of tranexamic acid for two minutes every six hours for seven days.
  2. Dermatologic surgery and injections or aspirations from soft tissues may be safely performed without reduction below therapeutic anticoagulation.
  3. Remote history (> 3 months) of venous thrombosis.
  4. Atrial fibrillation without history of stroke or other risk factors.
  5. Bileaflet mechanical aortic valve.

One Day Prior to Surgery Allowed For:

  1. If an arterial embolism occurred within one month of surgery, pre and post-operative heparin is indicated.
  2. Recent history (< 3 months) of venous thromboembolism.
  3. Mechanical mitral valve.
  4. Ball/cage mechanical aortic valve.


  1. Kearon C., Hirsh, J. Management of anticoagulation before and after elective surgery. N Engl J Med 1997;336:1506-1511.
  2. Kearon, C., Hirsh, J. (2003). Perioperative Management of Patients Receiving Oral Anticoagulants. Arch Intern Med 163:2532-2533.
  3. Dunn, A.S., Turpie, A.G.G. (2003). Perioperative Management of Patients Receiving Oral Anticoagulants: A Systematic Review. Arch Intern Med 163:901-908.
  4. Ansell, J.E. (2003). The Perioperative Management of Warfarin Therapy. Arch Intern Med 163:881-883.
  5. Spandorfer, J., Merli, G., Lowson, S.M., Hanson, E.W., Shalaby, A., Mohiuddin, S.M., Kearon, C., Hirsh, J. (1997). Anticoagulation and Elective Surgery. N Engl J Med 337:938-940.
  6. Ansell, S. et al. The Pharmacology and Management of the Vitamin K Antagonists. Chest 2004; 126:2045-2335.

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