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New Information On Afib Stroke Risk And Blood Thinners From The 2016 AF Symposium

At the recent Atrial Fibrillation Symposium, held January 14-16, 2016, in Orlando, I gleaned many interesting nuggets of information about stroke risk and blood thinners from the expert’s presentations. While we already knew some of these things, some are totally new information from research studies and from best practices by top experts and their institutions. Many of these experts are regularly part of the guidelines process, so their opinions are well worth listening to. 

When mentioned below, “new blood thinners” (often referred to as NOACs for new/novel oral anticoagulants) refers to the following drugs:  Pradaxa (dabigatran), Xarelto (rivaroxaban), Eliquis (apixaban), and Savaysa (edoxaban).

I’m sharing these nuggets as food for thought and for discussion with your doctors, but not as a replacement for your doctor’s advice. As always, please consult your doctor.

  • According to recent studies, those with paroxysmal afib have a lower stroke risk than those with persistent afib.
  • Getting high blood pressure (hypertension) under control is very important in reducing stroke risk for those with afib.
  • Warfarin has a 40-hour half-life, but may be up to 60 hours in some older patients; the new blood thinners have a half-life of 12-17 hours.
  • The FDA advised caution in switching among blood thinners, but switching is actually easier on the new oral anticoagulants because startup is so fast on them. Switching from them to warfarin should be undertaken with care.
  • One EP has had blood clots resolve in a month with the new blood thinners. In one study, rivaroxaban caused a 60% resolution in six weeks.
  • Studies measuring afib using implanted devices, such as pacemakers and implantable loop recorders, have given us more insight into the stroke risk with afib:
    • TRENDS Study — having multiple hours of afib doubled the risk of stroke and that increased risk lasted for 30 days.
    • ASSERT Study — afib of six minutes or more in the first three months can be a risk factor for strokes as much as a year or more later. It is likely that afib causes a pro-thrombotic (favoring the formation of clots) state that causes strokes long after normal sinus rhythm returns.
    • VA CareLink Study — long periods of afib raised the risk of stroke and this study supported the transient use of the new rapidly-acting blood thinners.
    • is an ongoing study of “pill-in-the-pocket” use of the new blood thinners — patients have an Implantable Loop Recorder (Reveal) and if they have an episode of afib lasting more than one hour, they are to take a blood thinner. This leads to a 94% reduction in blood thinner exposure and there have not been any strokes.
    • It is important to note that many of the experts were very concerned about using the new blood thinners as “pill-in-the-pocket” without an implantable loop recorder and under doctor’s supervision; they recommend against doing it outside of this study.
  • Should those with just one episode of afib be put on blood thinners? One expert stated that a test called NT-proBNP is a very powerful predictor of stroke risk and can be used as a tie-breaker if a doctor is on the fence as to whether or not to start the patient on blood thinners.
  • Adding aspirin to Plavix (clopidogrel) doesn’t decrease strokes, but does increase bleeds. Triple therapy — being on a blood thinner, aspirin, and Plavix (clopidogrel) for stents, all at the same time — leads to a four-fold risk of bleeds. (This is why patients who have to be on blood thinner for afib and Plavix after a stent are often advised to avoid aspirin.)
  • Reversal agents for the new blood thinners include:
    • Praxbind, for Pradaxa, which was approved by the FDA last year.
    • Andexanet alfa, for Xarelto, Eliquis, and Savaysa, is in testing and is expected to be approved this year.    
    • Ciraparantag, for all of the new blood thinners, is in testing.
  • Studies are indicating that bridging with heparin for procedures is dangerous and causes more bleeding; thus, many electrophysiologists on the panel stated that they leave patients on blood thinners for cardioversions and catheter ablation.
  • Work at the University of Utah is showing that:
    • Left atrial shape, as well as ventricle shape, is starting to provide us with some information for determining stroke risk. While this is really early — much too soon to make judgements from – this gives us insight into some of the research that may yield useful information in the future.
    • For those with small amounts of fibrosis (scar tissue in the heart), denoted as a Utah 1 (0%-5% fibrosis) or Utah 2 (5%-20% fibrosis) score, and with certain shapes of atria or ventricles, blood thinners should be continued.
    • For those with large amounts of fibrosis, denoted as having a Utah 3 (20%-35% fibrosis) or Utah 4 (more than 35% fibrosis) score, it is important to continue blood thinners regardless of the risk factors or amount of afib.
    • Their data shows that 70% of those over age 60 have 15% fibrosis or more, regardless of whether or not they have afib.
    • Learn more about fibrosis, Utah scores, and stroke risk at

This blog post reflects the opinion of the author and does not necessarily reflect the opinions of the AHA.
Posted by Mellanie at on Feb 16, 2016 12:24 PM America/Chicago


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Thanks so much for posting this Mellanie
  • Posted Wed 17 Feb 2016 02:15 AM CST
Interesting, but once again nothing mentioned about those of us with mechanical valves. There seldom is information applying to mechanica!l valves. We have a more difficult time than most. Hope you get the message.
  • Posted Wed 17 Feb 2016 06:08 AM CST

Thanks for this information! Very helpful to a new afibber.

  • Posted Wed 17 Feb 2016 06:48 AM CST
as always, many thanks for posting this and we welcome all new information in the future
  • Posted Wed 17 Feb 2016 08:56 AM CST
Thanks, all. Glad this was helpful.

pkn44, There was nothing mentioned because there is no new evidence (no new studies) regarding valvular afib. As of now, the new blood thinners are still not considered appropriate for those with mechanical valves. I'm sorry. For now, Coumadin is still the recommended treatment.
  • Posted Wed 17 Feb 2016 09:31 AM CST
So what I am surmising is that if you have afib, regardless of your CHA2DS2Vasc score, there are other things such as left atrial and ventricle shape
(not to mention left atrial appendage shape), fibrosis, length of afib episodes, and other factors, that make the case that you should take an anticoagulant, preferably a NOAC, no matter what.

Interesting that many EPs continue anticoagulants during ablation. What about colonoscopies and dental work?

So 70% of those over 60 have a Utah score of 2 or more, even if they don't have afib... hmmmmmmmm.

  • Posted Wed 17 Feb 2016 09:39 PM CST
Thanks for this info!
  • Posted Thu 18 Feb 2016 06:41 AM CST
A-fib is under control with Multaq, is it necessary to continue Eliquis? Dr. says yes. ????
  • Posted Thu 18 Feb 2016 08:04 AM CST
I am on Eliquis and thankful that a reversal agent is in the works.
  • Posted Thu 18 Feb 2016 08:20 AM CST
I am an AF 'sufferer' 2-3 times a month lasting 8-10 hours. 75 Female. No blood pressure to note 125/75.pulse rate 65-75, Parkinson and at risk of Osteoporosis.Working full time. Reasonably fit, vegetarian, healthy eater, don't smoke, occasional wine.
My cardio put me on Xarelto 20 MG a day around 2 years ago..I suffered a PE whilst on this drug. I have felt quite unwell only since starting it, terrible re-flux, nausea, severe joint pain and profound fatigue. Does any body in the medical community read what other are saying about this drug...we the ones who take it.
I have been told I shouldn't stop taking it by Dr and by the maker Bayer and Johnson...but not one of them will use the dreaded word REBOUND stroke.
Can someone answer this can I stop taking the drug. I am not in permanent AF. Out of 365 days in a year I have an episode 25 times on average.
Also why does someone my size 5'2" 56 kg need to take the same dose as a much larger person?
  • Posted Fri 19 Feb 2016 05:17 AM CST
does the same apply to people like me who are now in permanent A/Fib I take warfarin and always have done but am interested in the new drugs what do you think would be best for me .

I was interested in your comment about Heparin as I nearly died when this was given during surgery and had to have two blood transfusions and an emergency operation I will never have it again
  • Posted Fri 19 Feb 2016 09:14 PM CST
Thank you so much. Very helpful.
  • Posted Thu 10 Mar 2016 04:41 PM CST
Very good information!  Thank you for sharing.
  • Posted Tue 02 May 2017 09:01 AM CDT
We don't yet have the answer to that. It could be that fibrosis is decreased (though that is less likely), or that the enlargement of the atria decreases. Or, there could be dozens of other reasons - we don't know yet.

  • Posted Sun 11 Jun 2017 01:39 PM CDT