Re-coagulation by stopping Warfarin: how long?

[Thomas45]

The last time I was re-coagulated was with Vitamin K intravenously while in hospital prior to an operation to remove my appendix. I recently had a diagnostic colonoscopy which found 4 polyps in my colon, so I'm having another colonoscopy in 13 days time for them to be removed, for which I need to have an INR of 1.0, or at most 1.1. I take Warfarin to stay in the range of 2.0 to 3.0 INR. Some of you will have come off Warfarin prior to operations / ablations. How long did it take you to get to full coagulation? Yes I'm asking my arrhythmia nurse also, but my pre-op is less than 5 days before my colonoscopy.

[Hidden]

Hi Thomas,

Twice I have had to stop warfarin prior to a medical procedure. The most dramatic was knee replacement surgery - in both cases I had to stop warfarin 1 week before. So with knee replacement I stopped warfarin a week before being carved up, so that at the moment of surgery I was at 1.1. On returning to consciousness, post op, I was given two injections of Fragmin ( a bridging anticoagulant), then that evening I returned to my normal dose of warfarin.

I then continued with my normal dose of warfarin just as if nothing had happened.

I have the benefit of self testing and so have records to show how my INR levels returned to normal.

From the moment I stopped warfarin, when my INR was within range, to the day it dropped to 1.1, to the day I returned to being in range (INR 2.2) was 29 days.

Hope that makes sense.

Any questions, just ask.

John

[ILowe in reply to Hidden]

Questions: how often did you self test? Was the progress a steady increase, or was there a lurch upwards at one or more points?

[Hidden in reply to ILowe]

Its 3 and half years ago now and I have all the data stored on an external hard drive. Will need to check and reply but from memory I think I self tested every 2 days. Again from memory the data movements were steady and progressive.

John

[ILowe in reply to Hidden]

Thanks. That is helpful. I am now going to read up on how to start someone on warfarin. There are different methods. I want to know how I would do it if I was in this situation.

What puzzles me is this. I usually think of warfarin as like a charged paintbrush. First you have to charge up the brush, then you have to regularly replace the paint you use. Or I think of a reservoir, with constant input and constant output. If my framework is to work here, then there is a need to fill up the reservoir first, which would suggest some kind of priming, such as a high dose for a few days, then a normal dose.

[Hidden in reply to ILowe]

Hi there,

I managed to find my data relating to my partial knee replacement surgery. I hope it makes sense.

28 Oct 2015 I took my final dose of warfarin, then stopped all doses. My INR reading at this point was 2.2

1 Nov was 2.3

2 Nov was 1.9

3 Nov was 1.4

4 Nov was 1.3

6 Nov was 1.1

8 Nov was 1.3

10 Nov was 1.3

12 Nov was 1.5

17 Nov was 1.9

27 Nov was 2.0

1 Dec was 2.4

Surgery for partial knee replacement was around 11 am 6 Nov. Around 3 pm back in ward I was administered 2 doses of a bridging anticoagulant, Fragmin.

That night at 8 pm, my normal evening meds time, I returned to my normal doses for a Friday. I have continued uninterrupted ever since. Apart from the occasional day I have forgotten to take my evening med

I have to say I had a CT scan in Sept 2012 and also had to stop Warfarin for that and I do recall the data behaved in a similar way.

I have the data somewhere I'll try and locate and post them for you too.

Any discussion points please let me know.

John

[ILowe in reply to Hidden]

John. This is fascinating. For several reasons:

1/ One of the problems we self-dosers live with is absence of evidence. I would love to see such examples from over 100 people, tagged for different features so that I can evaluate for myself the trends and patterns.

2/ The overlap here with the starting warfarin from scratch debate, which basically circles round the question -- do we prime the pump by 1 or 2 high initial doses, or do we start with 5mg and wait and see.

3/ My biggest fascination and puzzle concerns the way warfarin dosing works once initiated. In my article on this I use the analogy of the reservoir. Stability means having the reservoir level high enough, then keeping the input=output right, which would imply in initiation the need to fill up the reservoir then back off. But here it seems that your previous stable point can be achieved through steady input over a longer period of time. The reservoir model does not seem to work for re-starting warfarin. I am really puzzled. What am I missing?

[Lowe I. 2017. Warfarin self-dosing, a case study on long term self-management of anticoagulation. Journal of Observation Pain Medicine Vol 6 pp 31-40. joopm.com

]

[Hidden in reply to ILowe]

Well, I managed to find the 2012 data.

In this case I had a CT Scan on 6 Sept 2012.

On 31 Aug 2012 I took my last dose of Warfarin and then ceased. My INR reading then was 2.8.

2 Sept was 1.7

3 Sept was 1.4

5 Sept was 1.1

6 Sept = CT Scan, I recall this took place late afternoon but cannot recall exact time.

The evening ( 8 pm ish, my usual evening meds time) of 6 Sept I returned to my normal Warfarin dose for a Thursday.

7 Sept was 1.1

10 Sept was 1.2

13 Sept was 1.5

20 Sept was 2.0

27 Sept was 2.3

Now I need to emphasize, following knee surgery I was administered Fragmin. Following the CT Scan I was not administered any bridging anticoagulant. None!

I should also stress that my normal theraputic range is ( and always has been) 2.0 to 3.0 with my target INR being 2.5.

So in the case of the CT Scan exercise it took 20 days to return to the lower value of my theraputic range (2.0) and 27 days to get back close to my target INR (2.3).

In the case of knee surgery it took 30 days to return to the 2.0 value and 34 days to get back close to my target INR 2.4.

I'll leave you to consider this very primative data collection stuff but it at least gives an idea.

What jumps out at me is why the knee surgery data take a longer time to return to normal than the CT Scan data .... is this to do with the Fragmin or simply as a result of the surgical procedure itself, the nature of the procedure.

I might add that at no time under either procedure did I have an AF experience.

What I am finding really interesting is how Gmc54 reports recently his data values .... and I quote ....

and it took 14 days to get my inr between 2 and 3.

end quote.

Compared to me, that is roughly half the time to return to his theraputic range of 2.0 to 3.0.

I wonder why.

Anyway, the point is we have in this discussion identified 3 different procedures which have produced 3 different results. Hmmmmm !

Could my approach to green veggies be involved here. I hate greens ! my wife almost has to force feed me greens.

I might add that over the years (9 and half years now since going on Warfarin), my dose has not changed, it is 5.2 to 5.3 mg/day and this is true of my two procedures I have referred to.

Hope this helps.

John

[Thomas45 in reply to Hidden]

Thanks for this information. I have consulted GPs who tried to convince me that bleeding in the colon from removal of the polyps could cause greater problems than being re-coagulated. I just feel so unprotected.

[ILowe in reply to Thomas45]

Overnight I realised I had missed an important variable: your gut. As you know, gut bacteria manufacture a significant amount of Vitamin K. Estimates are hard to find.

[ILowe in reply to Hidden]

Let me have a longer think and do some research tomorrow.

Concerning Fragmin (LMWH). This is a modern method. Once upon a time they kept you in hospital on a continuous drip. I may be wrong but use of heparin post-op until normal INR is achieved is falling out of favour because it increases the bleeding risk, which exceeds the embolism risk. It is reserved for those considered to be a 'high' risk, such as an artificial mitral valve. AF alone is down in the low risk box. I have experienced this. Twenty years ago, old system, the Heparin Drip, stopped for the tooth out. So far so good. A clot started forming in the socket. Then the drip was re-started and that clot worked loose. Despite constant pressure etc alternating myself and my wife, we could not stop the bleeding. The surgeon came in early and concluded the cause was the heparin and a tiny vein which leaked under the influence of the heparin. The cure was back to the operating room and cauterisation! Now that was for a visible wound.

Thinking about a related question -- why did they let you return to normal slowly instead of using initial booster doses? I now see that as wise. A slow return to normal INR makes healing easier. Fragmin could be given after say the 7th or 14th day then stopped/reduced if need be.

You wonder why one time took longer to return than the other. What were the other factors?

1/ the anaesthetic itself. We mere mortals rarely get to know what is used on us, and what about their effect on the INR? It could be long-lasting

2/ other medication

3/ age

4/ Margin of error in testing. If you used your own kit, this will be small (results are reliable). If you relied on the hospital lab, that could easily be 0.2 to 0.4 therefore not comparable.

5/ fasting, which increases the INR but is little studied.

6/ something else

7/ the fact that we humans are not standard and not consistent, and the possibility of inconsistency must always be considered. I found for instance that after the heparin drip week, my dose needed for stable INR was increased. A warning I heeded years later when I stopped Amiodarone. Vigilance is required even after the return to normal.

[ILowe in reply to Hidden]

Interesting in a brief look at the literature, they do not seem to debate the question of restarting warfarin in terms of boosting it. Their concern is the big ones -- clotting and bleeding. it seems that using Heparin after the op increases the bleeding without necessarily reducing the clot risk, therefore for most people (except high risk patients-- NOT just AF) then use of Heparin after the op is not a good idea.

[Gmc54]

I stopped my warfarin in order to have a colonoscopy. I was told to stop a week before the procedure, by the time I had the test my inr was 1.1. I then started my usual dose as instructed by my warfarin nurse, and it took 14 days to get my inr between 2 and 3. It was a worrying time, as I has an episode of afib lasting over 24 hours during that time. I was given no other anti coagulation, and I couldn’t get in touch with my surgery as it was over the Christmas period, and they were closed.

They found no problem with my colonoscopy thank goodness, but I’m not sure if I would be prepared to put myself at risk like that again when it’s time in a couple of years for my “poo sample”. Its a bit of a catch 22 situation.

[Thomas45 in reply to Gmc54]

Thanks, I know how you felt. I am in permanent AF, 24 hours a day, 7ydays a week, but if the polyps are allowed to grow they are likely to become cancerous.

[mandysmith34]

I wouldn't be happy stopping warfarin at all unless it's being bridged by heparin or similar and you're under direct medical care. You're opening yourself up to a huge risk of stroke. It's not worth it

[Gmc54 in reply to mandysmith34]

Yes, I know what you mean, in fact when you have a colonoscopy after they find blood in your sample they tell you that you don’t have to stop the warfarin, for the procedure - but - if they find something during the procedure the cannot remove it, and then you have to go through it all again, after stopping the anticoagulant, I didn’t want to go through it all twice, so opted to stop the warfarin. I had no idea it would take two weeks to get my inr back to where it should be. I think if you are on the new anticoagulants I’m almost sure you only have to stop a couple of days before, and you can start back on them the day after the procedure.

[Thomas45 in reply to Gmc54]

I have tried one of the new anticoagulants and I found I was the one person in 10,000 who take that anticoagulant to have very painful side effect which took years to get over. So rather than try another new one I went back to Warfarin and bought my own Coaguchek monitor.

[ILowe]

A relative taking warfarin for an artificial heart valve recently had it stopped. When they restarted warfarin, he was taught to give himself Heparin jabs until he came into range. I heard a nurse say "they are bringing him up slowly".

Years ago I had the "heparin bridge" which meant a continuous drip of heparin into a vein for a few days until I was over 2.0. I was not amused to be confined to a drip since I was otherwise fit. In my case I had to stop warfarin for 3 days and restarting took 2-3 days. Another time my relative in similar circumstances was not allowed out until he had two results >2.5 on two successive days, and if that hits the weekend, then you stay the weekend.

My guess is that they are fussier for high risk patients like those with artificial heart valves. I have also seen the trend over the years, to send you home with Heparin.

Important point. After you have stopped warfarin, you cannot assume that you will be stable on the previous dose. Stopping it somehow shakes up the system. You might need slightly MORE warfarin, or you may need less.

[rosyG]

I'm not medical and not advising this but I have brought my INR down quickly by eating a lot of spinach.......

[Thomas45 in reply to rosyG]

Unfortunately the bland diet you have to eat 3 days prior to your colonoscopy doesn't allow for any fruit or vegetables. However see my next post below.

[Thomas45]

In the event my INR on the Friday just over a week before my colonoscopy was 3.9, so I decided to stop then. By the Tuesday it was down to 1.5, but worryingly for me it had only fallen to 1.3 by the Thursday before the Sunday morning colonoscopy. On the following day it was still 1.3. I didn't take another reading. The nurse had said it must be at 1.1 for the colonoscopy to take place.

So I went through all the preparations. A Sunday morning colonoscopy meant taking the second litre of "Moviprep" immediately after the first litre, and 10 hours from taking the first mouthful to what I thought was the last visit to the loo. I had 3 hours sleep and then further loo visits at 6am, 7am, and 8.30am. At 10am I set off on two buses to the hospital. At the final check of ailments, medical allergic reactions, the fact I didn't want sedation, etc, out came a hospital INR meter. I waited for the result. It was 1.3 again. I mentioned my earlier readings on my own Coaguchek monitor and the consultant decided to go ahead. 3 small polyps were cut off with a cold blade, and they bled a little. The 4th, larger polyp was cauterised, so no bleeding.

I now believe 1.3 is as low as I go. I was allowed to re-start my Warfarin on Sunday night. Later today I will check my INR.

[rosyG in reply to Thomas45]

That’s great. Well done! Keep a record in case you have future procedure.