Tuesday 25 July, 2006

How to stop warfarin for surgery

Posted in General Practice, Medicine, Michael Tam, Surgery, Wards at 20:14 by Michael Tam

Index: Anticoagulation :: Printer friendly

Original article by: Michael Tam

One would think that there would be guidelines on how, when or if warfarin should be ceased before surgery but the reality is that this is often not the case. I remember working as a surgical resident in the pre-operative clinic and having to make this decision on the fly. I can only hope that the anaesthetic registrar who conducted the (parallel) anaesthetic clinic knew what he or she was doing.

In a nutshell:

Low thromboembolic risk:

  • stop warfarin 5 days pre-op;
  • restart warfarin post-op as soon as oral fluids are tolerated.

High thromboembolic risk:

  • stop warfarin 4 days pre-op and start low molecular weight heparin (LMWH) at therapeutic dose;
  • stop the LMWH 12-18 pre-op;
  • restart LMWH 6 hours post-op (assuming haemostasis achieved);
  • restart warfarin when oral fluids are tolerated;
  • stop LMWH when INR = 2.0.

See below for details

Most patients are on warfarin for a good reason and its cessation may lead to a thromboembolic event. I do not believe that the risk has actually been quantified, though a useful indicator is to look at the risk of ischaemic stroke in patients on long term aspirin after its cessation. There is over a 3-fold increase in risk (1), i.e., substantially higher than the baseline risk for someone who had never taken aspirin in the first place.

Nevertheless, this has to be balanced against the increased risk of a substantial peri-operative bleed from anticoagulation. I find the following algorithm (2) instructive (adapted from Sridhar R., Grigg A.):

Risk of thromboembolism if anticoagulation is withdrawn
  Low High
Atrial fibrillation and/or cardiomyopathy Without stroke or systemic embolisation in the last 12 months With stroke or systemic embolisation within the last 12 months
Biological heart valves Except during first three months During first three months
Prosthesis Vascular grafts Cardiac mechanical valves
Venous thrombosis Not within the last three months and without a confirmed hypercoagulable state Within the last three months, or recurrent venous thrombosis
Systemic arterial emboli Non-recurrent Recurrent
Note: two low-risk factors = high risk

Recommendations for perioperative anticoagulation of patients undergoing major elective surgery
Day Low-risk patients High-risk patients
-5 Cease warfarin  
-4 No anticoagulation Cease warfarin:

  • Measure INR
  • Start full dose unfractionated heparin (UFH) infusion as inpatient OR LMWH as outpatient.
  • Continue daily until day -1.
-1   Stop LMWH a minimum of 12 hours and UFH six hours before surgery.
+1 Start warfarin as soon as oral fluids tolerated using the preoperative maintenance dose. Once haemostasis secured, and generally after at least six hours post surgery:

  • recommence LMWH (preferred) or UFH
  • start warfarin as soon as oral fluids tolerated using the preoperative maintenance dose


  • Where in doubt, especially in someone with a complex medical history or an unusual clotting disorder, ask for help from the haematologists.
  • At the end of the day, there is very little that you can do for thromboembolism while bleeding is often salvageable. I would err towards bleeding (or where it is particularly problematic, postponing surgery).
  • It is the surgeon who cuts the patient so the above algorithm is only a guide. Many surgeons are much more anxious about operating on an anticoagulated patient.
  • Don’t forget that elective operations are elective (i.e., optional and possibly unnecessary). Someone who comes in for a total knee replacement and then suffers a massive disabling stroke is an absolute disaster. Be especially careful with the elective patients.

Reference articles

(1) Maulaz AB., Bezerra DC., Michel P. Bogousslavsky J. Effect of discontinuing aspirin therapy on the risk of brain ischemic stroke. Archives of Neurology 62(8):1217-20, 2005 Aug. [Link]

(2) Sridhar R., Grigg A. The perioperative management of anticoagulation. Aust Prescr 2000;23:13-6. [download PDF :: 161 Kb]

Please read the disclaimer


  1. Suzy Patterson said,

    I have a really strong family genetic disorder, I am protein S deficient I am 61 my 4 siblings are protein S and or S & C neices and nephews have had extremely serious episodes, my son had a stroke at 20 , our clots are venous I have had less problems than the others, but had a superficial clot in the saffronous vein in July was put on coumadin, I came off last Sunday and Im now taking whole aspirin. My legs hurt so badly while I was taking the coumadin. I came off for minor surgery. Discussed with my hemotologist and since I gave birth twice with no problems and this was the first spontaneou clot we decided to try the aspirin. How great is my risk??

    • Lynda said,

      anyone here on Coumadine because of Lupus? Lynda

    • Lynda said,

      no one here has mentioned taking the Lovenox shots while off Coumadin??????? Lynda

  2. Michael Tam said,

    Dear Suzy,

    I am not a haematologist so that question is best directed at your regular practitioner. It certainly sounds like you are at high risk from a family history point of view. Nevertheless, the fact that you’ve only had a single superficial thrombus by the age of 61 must be taken into account as well.

    Best regards,
    Michael Tam

  3. Chris Adams said,

    I need to have a bakers cyst asperated, when should I stop the coumadin? Do I tapper off, or stop abruply? And then when should I start it again?

  4. Michael Tam said,

    Dear Chris,

    I would highly recommend discussing these practical concerns with your regular General Practitioner. I am not your regular physician and do not have all the clinically relevant information. Depending on the actual procedure and the reason that you are on warfarin, you may not even need to stop the warfarin.

    IF the warfarin needs to be discontinued, it does not need to be tapered and is generally ceased 4-5 days prior to the procedure. Depending on your risk, you may need an alternative form of anticoagulation. The article that this comment is attached details some recommendations.

    Again, please discuss these issues with your regular doctor well in advance of the procedure.

  5. Simon Hill said,

    I had an aortic valve replacement (replaced with a mechanical one) in 2000 and consequently take warfarin for life. My INR is meant to be between 2.5 and 3.5 and had been stable at about 3 for some considerable time (I take 3mg daily). I am 24 years old.

    I am seeking elective surgery (male chest reduction – medium liposuction) and have been warned of the risk involved by having to cease warfarin for a short time in order to obtain an INR level of 1 pre-surgery. I am concerned about the risk of clotting and consequential stroke that could follow.

    Do you know much about warfarin patients with a relatively low INR level under going surgery with little reduction in INR level? I would have thought that a level of 2 might be a possibility rather than 1 – as it would reduce the risk at least. I suppose it would be up to the surgeon to accept that at the end of the day but I have read some posts on the internet re studies of patients with INR levels of 1.1 to 3.0 not having to cease their warfarin intake for minor surgery.

    Any advice or tips (other than consulting GP)?


  6. Michael Tam said,

    Dear Simon,

    As far as I know, there is no particular advantage with aiming for an INR at the lower end of the therapeutic range with regards to the increased risk of bleeding in surgery. You are quite correct that there will be an increased risk of thrombosis when you anticoagulation is discontinued, but this of course must be balanced by the risk of operative bleeding.

    With your valve replacement, your risk of thrombosis would be high so I would imagine some form of therapy as mentioned in the appropriate section of this article would be needed.

    Insofar as minor surgery while anticoagulated, you have correctly identified that it very much depends on your surgeon.

  7. Mitzi said,

    I had a stroke in my cerebellum in 2005 and have been in warfin since. Doctors have run all the test they can and there is no medical reason for the stroke. I was only 35.
    I am considering having liposuction on my stomach. I would be under only local anesthetic. My family doctor feels it would be ok, however I do need the ok from my neurologist.
    Have you ever heard of someone actually bleeding out from this type of procedure? Any suggestions?

    A little vain

  8. I have PHN for many years. The Pain Clinic offers me a procedure to ease the pain, provided I stop warfarin five days prior to said operation. My MD leaves the decision to me….I do not know what to do. What is your opinion on the subject?

  9. Please give me the pros and cons of wirhdrawing from warfarin five days before said procedure..
    Thank you in advance.

  10. I am on 7.5 mg daily of warfarin…I was told of my MD’s response yesterday and am waiting for the next blood test, due on January 9. Is my case, according to the amount of warfarin I am prescribed is benign/medium/ or quite serioius? By the way is there any chance that my blood will return to normal at any time? I am 84 years old and have a pacemaker implanted on April 2008…
    As i mentioned before my MD left the decision to me….what are my chances?

  11. First of all, we are Tuesday the 30th of December 2008….
    I would appreciate some sort of answer from you… all I do so far is state my case…what is your opinion of my case?

  12. Michael Tam said,

    Dear genevieve,

    I would strongly suggest that you make an appointment with your regular practitioner to discuss these issues. I do not have all the necessary information or even basic information (e.g., why you were started on warfarin). As such, there no way I can advise you on your risk on stopping warfarin. Some of the questions that you have asked suggest to me that you have an incomplete understanding of the purpose of your warfarin therapy.

    My opinion is that you should discuss any pending procedure requiring the cessation of warfarin with the doctor who normally looks after your warfarin as you will most likely need to restart warfarin.

    • Lynda Fowlie said,

      Hi, new to this site, but I noticed all these people are not mentioning the Heprin bridge or the use of Lovenox, I didn’t know about this till after my back surgery and the following strokes? I wonder why the doctor’s are informing their patients… ??

  13. Dear Michael Tam:
    I am taking warfarin since a pacemaker was implanted on April 1, 2008. Prior to this my blood was normal. I have questioned my MD regarding the risks of the projected operation performed by a Pain Clinic and his answer was that I should take the decision to operate or not…I then asked to you whether it is safe to go without warfarin for five days before the operation…
    Very trul yours

  14. Dear Mr. Tam:
    I just re-read your a nswer to me. I understand that warfarin is prescribed to prevent blood clots, etc. I take 7.5 mg. regularly and my blood is analyzed periodically to regulate the amouint of warfarin I need. After having a weekly check, then a two week check, I am now at three week check which I consider progress.
    Is there any chance that my blood will return to normal and that i will not need to take blood thinner?
    Very trulyours,

  15. Candy Thomas said,

    Why Heparin sodium administered subcutaneously can be administered the day before surgery, butt my surgeon delay elective surgery for several days to a week cuz I am receiving coumadin(warfarin)?

  16. Noodle said,

    Thankyou for this excellent post on stopping warfarin

  17. kcrcp66 said,

    I have DVT and am on coumadin….im only 45…nonsmoker ,, non drinker….neg. family history…..they think the DVT happened because i have lupus.

  18. lsebri said,

    My mother was on Coumadin for several years. The doctor stopped it to do a biopsy on her kidney. He did not resume it while waiting on the results. Five days later she suffered a stroke? Is it the lack of medication that brought on the stroke?

    • Lynda Fowlie said,

      she shsould have been on the Heprin bridge, which is Lovenox shots to prevent the clotting???????

  19. ken said,

    I have a-fib was operated on bilateral hip replacement dec 3. Surgeon and cardiologist put me on coumidan. Still on at present and want to get off it. My PCP believes I am at risk for an embolism being on coumidan wants to put me on xarelto. What do you see with this situation or suggest. Thx

    • Lynda Fowlie said,

      I have a-fib + lupus, I therw 5 pulmonary embolisms 30 years ago and have been on coumadin since, I had back curgery 2 years ago, during the 3 procedures I needed I was taken off coumadin, you have to go on a heprin bridge to prevent the clots, and at the time I didn’t know that, so I ended up having 3 mini strokes, my advice is not to let them take you off unless you do the lovenox shots, you can do them at home if necessary although the RX is expensive!!!!!, If you are near the Dr or hospital you can go in 2X a day and your insurance should take care of them.

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