AF and blood clots

I am Cali111 and went for an ablation last Wednesday 21/9/16 but it was stopped after the scan showed a blood clot at the back of my heart. I have been taking Apixiban for a year but the consultant said this was not a recent clot, so is apixiban as good as warfarin or not.? They have swapped me to Warfarin high dose of 9mg and I have to redo the scan in six weeks.

41 Replies

  • Very interesting but how long do they think it had been there? Some questions spring to mind:

    1. Does the apixaban work less well than warfarin?

    2. Could your INR have been on the low side in between blood tests when you were on warfarin?

    I guess you may never know but thank goodness they found it!

    I feel for you though . After the emotional build up to ablation, it is not great to come to a grinding halt. Hope they get rid of the clot quickly. X

  • I have only just been transferred to warfarin as of Wednesday when they found the clot but when I went for my pre-op my level was 1.4. The consultant did not elaborate how long the clot had been there his words were "It is not recent" and he was reluctant to comment when I asked why Apixiban did not prevent it. It is of concern to everyone who takes Apixiban and not Warfarin and questions the efficacy of Apixiban as an anti-coagulant.

  • Cali111 I was started on Apixaban but had very bad side effects,kidney problems,then Riveroxaban which was just the same so then went on Warfarin and no problems at all.

    Overall it took 6months to get sorted as I was termed at risk and needed an anticoagulant. Best wishes

  • Cali

    Sorry but this doesn't add up. If you are on Apixaban the INR is totally irrelevant as Apixaban works a completely way and INR is NOT a measure.

    IF your INR was taken before you started warfarin then one of two things. I am guessing that they did the finger prick test rather than taking blood from your arm and sending it to the lab. With the finger prick there is often a 0.1 difference which can be 0.2 and in addition there is a margin of difference on venous testing which can be the same.

    Either your natural INR is higher than 1.0 which it is for many people. Mine is 1.1 and I know some have 1.2. Alternatively they weren't very quick and the blood had started thickening slightly in which case this could have added a further 0.1 or 0.2.

  • I don't follow either PeterWh and thought I had misunderstood. Why do an INR test on an Apixaban patient?

    cali111 Good that the clot was found but it must have been a letdown when you had geared yourself up. Your post is of interest to all of us taking Apixaban but there are points that I don't understand.

  • Jan last year I was switched from Apixaban to Warfarin because (well certainly at that time) the hospital where I am under would only do an ablation if on Warfarin.

    Went to the local anticoagulation clinic for the switch and on the Monday morning I had an INR test (which was 1.1). This was so they had a base INR to start the program off (they also enter in other things such as age, weight, etc). Then they told me the warfarin dose to take and to continue taking BOTH Apixaban and Warfarin and to go back on the Friday morning for a second test. Normally it takes 1 to 3 weeks for INR to get up but by the Friday I was in range (I think 2.2) so they told me to stop Apixaban).

    I suspect that Cali's was again to have the starting point for the program.

  • Thank you - it makes sense now.

  • My GP told me that no matter which anticoagulant is being taken there is always the chance of a blood clot, albeit a very reduced chance.

  • Quote from internet "New oral anticoagulant failure: In the studies that compared Xarelto to warfarin in the treatment of DVT and PE, recurrent VTE occurred in both treatment groups equally often, i.e. in 2-3 % of patients over a 1 year treatment period [ref 5,6]. If a patient who is being treated with one of the new oral anticoagulants has clearly documented recurrent VTE, then a treatment change seems appropriate. I would choose and discuss with the patient a switch to warfarin, long-term. However, it is not known how effective that is in preventing recurrences."

    Other risk factors for blood clotting may be worth looking at such as Factor V leiden. It may be worth asking for an haematology referral to consider this

  • I queried this test at the time as I was not on warfarin but they measured it anyway. All bloods were drawn from my arm.

  • I think PeterWh 's explanation above about the base INR before Warfarin is used is probably why it was done.

  • Fonvola is right. Yes that's definitely the case of setting the baseline. Even if you hadn't been on any coagulant they would have done the test. If they had assumed that it was. 1.0 and started you on warfarin and after 4 days the second test showed that you were at 1.8 the programme would assume that 0.8 was due to the warfarin and then would reduce your dose. Say it started at 5.0!which is quite common they could reduce to 2.5 or 3 mg. This would then mean that your one could actually fall over the following 4 to 7 days and could mean it took an EXTRA 1 to 2 weeks to achieve something in the low 2s. All that time you could have been sailing along not being anticogilated and so at a much higher risk of a stroke. Ok in your case being on apixaban for some of that time.

  • Maybe you should ask the consultant to clarify his comments they seem a little bit vague he may be able to answer your question is Apixaban is as good as Warfarin. hope the scan goes well.

  • I don`t think that they know yet as the drugs are new so the doc would not commit.

  • Which is best. Beef or Lamb? Potatoes or Sprouts? You can't compare apples with pears so neither can you compare NOACs with warfarin. As has been said already the INR test was a waste of time since Apixaban does not work on Vit K as does warfarin but a completely different part of the clotting process. One can only assume that the nurse at pre op is pre programmed to perform a set number of tests regardless of need.

    It should also be understood that no anticoagulant would normally dissolve a clot so this may well be a very long standing one hiding most likely in the LAA (left atrial appendage) and found by the pre-ablation TOE. I am equally confused that they have not apparently given you any clot busting drugs but they must have their reasons.

    Lots of questions for the consultant for sure.


  • As I understand it clot busting drugs are for life threatening condition and I think they want this to disperse naturally as minute amounts of a clot can stick to the RF probes leading to a stroke, - but I could be wrong!

  • Sorry Bob but I disagree. The INR test was not a waste of time it was to set Cali's base INR so that when the second test is done the program uses the amount of warfarin taken and the difference in INR to calculate the second dosage.

    When I was started on warfarin the lead Anticoagulation nurse for the whole area told me contrary to popular belief most people do not have a base INR of 1.0.

  • Maybe I read this wrong then Peter but the way I did the INR test was before the attempted ablation at pre=op when on apaixaban. It was only after the discovery of the clot that warfarin was considered. Yes just read it again and still think that.

  • When I accidentally severed an artery in my hand back in January they injected Vitamin K to reverse the anticoagulation effects of the Warfarin in order to stop me bleeding so badly (tourniquet on and off for nearly 2 hours).

    Interestingly I had discussed alternatives to Warfarin with my EP a couple of weeks earlier and he gave me a similar explanation to Peter's in that the new drugs cannot be measured in INR terms the way Warfarin is.

    For this reason he said I should think hard on the subject.

    With my accident 2 weeks later I am not sure what would have happened. It was scary enough as it was!

    For you it just shows how valuable the TOE scan is. Glad they found it and let's hope that the problem can be resolved.


  • When they gave me vit k to reduce INR and stop a potential internal bleed, it took 12 hours to reduce INR. From 2.7 to 2....not exactly quick!!

  • Yes it can take a while and then has to be reversed once the crisis is over.

    It was very scary for me as they had to transfer me to another specialist hospital for microsurgery and needed to stablise my bleeding for the ambulance journey of about 40 minutes.

  • Took 36 hours for my INR to drop from 2.3 to 1.2 and that was with two lots of vitamin k doses!!!

  • My 4h ablation was postponed because the TOE discovered a clot in the LAA. I had had to come off Dabigatran and go onto warfarin for the ablation. I was not anti coagulated for 2 weeks and I blame that time. My EP seemed to think the clot happened whilst I was on Dabigatran. I had to stay on warfarin for 6 mths whilst clot dissolved. No other change in medication. 18 mths after the ablation I have been put back onto a NOA C but the only one I was allowed was Edoxaban. I am to have s TOE after 3 mths.

  • How did you find the TOE? Mine was horrible i think they were heavy handed with the throat spray and i felt very panicked. I have had endoscapy befor which were nothing like this!

  • I had sedation which creates amnesia for the TOE procedure so much better option ask for sedation if you can when they do the next TOE.

    I had an endoscopy a few years back then I had the throat spray it was horrible.


  • Thanks. They did give sedation but it only kicked in late just as i was panicked but remeber it - I did!

  • That is a shame I guess the amnesia kicks in at different stages depending on the dose and exactly when they administer it. Perhaps you can ask for the injection to be done a bit earlier next time.

    I agree with you the spray is awful as it is when they first push the probe in.Pete

  • That is worrying I am on DABIGATRAN I thought it worked well to prevent clots. 😔

  • I still do. I think my EP was wrong in stopping it and starting warfarin. I think they should have been overlapped. But the consultants are learning all the time as are we.

  • I thought so too with Apixiban - it was a shock when they found a clot.

  • I am coming to the conclusion that Warfarin is better than the newer ones. The evidence seems to be mounting and I feel we are guinea pigs gor these newer ones

  • Personally I think it was during the two weeks between the two. This has been identified as a higher risk period. Don't know why they did that. Certainly changing from apixaban to warfarin it was taking both until INR was over two. Half life of Dabigatran will be somewhere between 12 and 42 hours I'd have thought.

  • Totally agree but EP didn't concur.

  • Absolutely - guidelines from Cumbria NHS for changing from Apixaban to Warfarin advise using both for al least 2 days and discontinuing Apixaban only when INR has reached 2.

  • I have always had a GA. Couldn't do it otherwise. Gag reflex is so strong and EP doesn't want me to move.

  • In addition to sedation method I too have had 2 TOEs which were done under GA - part of checks as they started the ablation. Good to not know.

    Mind you I lost my voice for two days once.


  • Since being back on a NOAC I have had no nose bleeds or worry about eating the right things at the right time. Guess the next TOE will support my optimism...ot not.

  • Cali111. This leaves me just a diddy bit worried. I have taken (so I thought) my last Warfarin dose today prior to starting on 20mg daily of Rivoroxaban next week. One more INR to check whether my reading is less than 1.8 ready to start with the NOAC on Weds. I thought NICE had checked all this out which was why they approved the new anticoagulants. Hmmm.... I have been lucky twice in the past having had a DVT, and my AF was only discovered after it was discovered (A+E, severe chest pain) that I had bi-lateral PE). Ah well, If I kick the bucket (third time unlucky) I hope I go with me boots on like Tommy Cooper! George

  • I seem to remember that there is at least 1 forum member that had TIA whilst on warfarin. Taking anticoagulats dramatically decrease stroke risk but dont totally eliminate it sadly. X

  • I am completely lost when it comes to Warfarin. My results from my first blood test show 3.5 INR so they have reduced my dose and another blood done next Tuesday. I hope my next TOE is a good one. My breathlessness is tremendous and so I fight for my breath as soon as I move. Does this happen to everybody with an irregular heart beat. My pulse is between 80-95bpm.

  • All it means that your body has absorbed the warfarin very quickly. For many people they can be on warfarin for three or four days and their INR has only gone up by say 0.3 or so. Warfarin is a slowish acting medicine so if you did a blood test the next day after starting it for the first time someone's INR will almost certainly not have changed. Once you get the INR roughly mid range then they calculate the maintenance dose but don't worry that INR fluctuates a bit. It hardly ever stays exactly the same!!!

    People's bodies vary significantly so if you ignore differences in vitamin k intake (eg green veg, green salads, etc) one person could be on 3mg per day and the next person on 10mg per day. I think it was Bob who said he knew someone who took 18mg per day.

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