hi . when we are on warfarin and we are out of the required range .as in 2 to 3 . does this mean we could still have a stroke ?

had my second ablation just over a week ago . so ive been on warfarin for a month or so .and in all that time i dont think ive been in the required range . the day before my opp it was 3.5 . so i missed a dose and it came down to 3.2 . i was lucky

16 Replies

  • better to be on the high side to prevent a stroke. As has been said many times on here, between 2 and 3 is the goal, but many things can put your figure outside that range. Of course you prob only have it checked once a month, so who knows what its doing on the other 30 days?

    Mine has been recorded at over 5 on the odd occasion, but usually if i have had a cold or on one occasion diarrhea, it takes some time to get used to the fact that it might not always seem to be stable.

  • ta mate . was on warfarin for 6 months around the time of my first ablation and found it easy to stay in range . but this time round im struggling . and i dont know why ?

  • 2 to 3 is a a bit old hat really. At HRC last October we were told that due to the inaccuracies of testing INR we would be better aiming for 2.5 to 3.5 and also that there was not extra risk of bleeding up to about 5. Regarding actual stroke risk, the point is that untreated we have a five times greater stroke risk than somebody without AF. It doesn't mean you will have one if out of range.


  • if you are below 2 the chances of a clot forming increase and if you are over the top of your range the chances of bleeding- inter-cranial and elsewhere increase. There is an excellent graph somewhere on this forum showing the figures but I couldn't locate it just now!! I had a strange month last month but back in range now after adjusting doseage. Are you self- testing?- easier to keep in range if you are!

  • Hi Rosy,

    Was this the graph you referred to?


    it shows the risk of a stroke depending on INR. Basically the risk of a thromboembolism shoots up below INR of 1.8 and the risk of a brain bleed shoots up above an INR of 3.5. I found this graph to be the most interesting and informative thing I've ever found on anti-coagulation.

    I actually disagree with the advice to keep your INR in the range of 2.5-3.5. There's actually more risk of exceeding 3.5 when trying for that range than going below 2 when on a 2-3 regime.

    Ideally you would aim for 2.5-3 but that's not always easy.


  • I clicked on the link but did not get the page. ncbi.nlm.nih.gov is an interesting site though. Your answers are always very useful.

  • Sorry about that, hopefully it'll work with this:


  • Bingo! Very many thanks, mark

  • Those are very interesting and graphic - as any graph should be! I like the expression '95% confidence interval'

  • Mark- great that you have posted the graph now- I had printed it out when you find showed it to us and think it's very helpful. I have copied the comments in the study here ( thinking the graph had disappeared online) think it's very helpful and great you found it some time ago

    Methods and Results

    We conducted a case-control study nested within the ATRIA cohort’s 9,217 AF patients taking warfarin to define the relationship between INR level and the odds of thromboembolism (TE, mainly stroke) and of intracranial hemorrhage (ICH) relative to INR 2.0-2.5. We identified 396 TE cases and 164 ICH cases during follow-up. Each case was compared with four randomly selected controls matched on calendar date and stroke risk factors using matched univariable analyses and conditional logistic regression. We explored modification of the INR-outcome relationships by the following stroke risk factors: prior stroke, age and CHADS2 risk score.

    Overall, the odds of TE were low and stable above INR 1.8. Compared to INR 2.0-2.5, the relative odds of TE increased strikingly at INR <1.8 (e.g., OR=3.72; 95% CI: 2.67-5.19, at INR 1.4-1.7). The odds of ICH increased markedly at INR values >3.5 (e.g., OR=3.56; 95% CI: 1.70-7.46, at INR 3.6-4.5). The relative odds of ICH were consistently low at INR <3.6. There was no evidence of lower ICH risk at INR levels<2.0. These patterns of risk did not differ substantially by history of stroke, age, or CHADS2 risk score.


    Our results confirm that the current standard of INR 2.0-3.0 for AF falls in the optimal INR range. Our findings do not support adjustment of INR targets according to previously defined stroke risk factors.

  • Moggdog, For my last ablation, the EP gave me a target range of 3.0 - 4.0 (just for the op). Didn't get there but they still went ahead anyhow.


  • hi koll . they tested my inr on morning of my ablation . and my ep said if i wasnt under 3.5 he wouldnt go ahead with op . but i was lucky i was in range .

  • Well there you go. I may be remembering my range incorrectly but I was sure it was 3-4 he wanted. My EP went ahead with an INR of 2.5'ish as it happens.

  • I have been assured that when my INR is 2 or below (as it always has been) I am getting some protection and a low INR is better than not taking warfarin at all.

    As I understand it, it is a bit of a tightrope and you need to strike a balance (as RosyG has said) between having an INR too low (so that your blood is more likely to clot and cause a stroke) and having too high an INR so that you might bleed or bruise excessively. It has been pointed out to me that the advantage of warfarin is that a dose of vitamin K will decrease the INR if you have an accident or are having surgery.

  • The answer to your question surely must be Yes, but you can also have a stroke even if your INR is within the optimal range. Anticoagulants reduce the risk but they do not completely eliminate the possibility of stroke.

  • I agree I have been on Warfarin since 1992 and have been up and down more times than the BT Towers Lift. The way I look at it is if it is above 2 and below 4 not to worry I have been up to 5.6 which was not good. Keep away from brassicaceae vegetables and Cranberries. I was told to keep away from vitimins?

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