#356 Does Aspirin Prevent Atrial Fibrillation Strokes?

Does Aspirin Prevent Atrial Fibrillation Strokes?

Unless you or someone close to you has experienced an atrial fibrillation stroke, the idea of taking a blood thinner might not be appealing. Many people are understandably worried about the risk of bleeding, and the financial aspect adds another layer of concern. For individuals without good drug coverage, popular blood thinners, like Eliquis or Xarelto, can cost a staggering $600 per month in the US, often surpassing the expense of a typical monthly car payment.

Considering these factors, it’s not surprising that I often get asked this question in my clinic: Can aspirin stop strokes caused by atrial fibrillation? Even though I wish the answer was yes, unfortunately, it’s probably not. In this article, we’ll explore the risk of strokes related to atrial fibrillation and look into the data about whether aspirin can actually prevent these strokes.

How Do Blood Thinners Prevent AFib Stokes?

Since atrial fibrillation raises the chance of having a stroke, doctors frequently recommend anticoagulants. These drugs, also known as blood thinners, aid in averting the formation of clots within your heart. The lower the risk of developing a blood clot in the left atrial appendage, a situation that may occur when the upper heart chambers stop beating during AFib, the less chance there is for a clot to dislodge and block the blood supply, leading to a lack of oxygen to the brain or other parts of your body.

Our Aspirin AFib Study

For a long time, aspirin was thought to be protective against stroke. It turns out, though, that this cheap and common remedy is actually not all that helpful. While it would be nice to think that lowering the risk of stroke was as easy as “an aspirin a day,” a study we did a few years ago demonstrated that aspirin, even in people at lower risk of stroke, simply doesn’t work very well for this purpose and, instead, puts AFib patients at risk in other ways by increasing their risk of bleeding both in the brain and elsewhere. So, In these 4,124 patients we studied, we found that not only did aspirin not help prevent strokes caused by AFib, but it also increased the chance of serious bleeding that could be life-threatening.

What Do the 2023 AFib Treatment Guidelines Say About Aspirin?

In the latest AFib treatment guidelines, the authors didn’t even give aspirin the time of the day. In fact, the wording was quite strong: “In patients patients with AF who are candidates for anticoagulation (blood thinners), aspirin as an alternative to anticoagulation (blood thinners) is not recommended to reduce stroke risk.”

Put simply, if you have enough risk factors for stroke due to AFib (CHADS-VASc score of 2 or higher), don’t even consider using aspirin as a replacement for your prescribed blood thinner. If you’re unsure on whether you should take a blood thinner or not for your AFib you can quickly CHADS-VASc Score.

Congestive heart failure: 1 point

High blood pressure: 1 point

Age 65 or higher: 1 point

Diabetes: 1 point

Stroke or TIA history: 2 point

Vascular disease (blockage in any artery): 1 point

Age 75 or higher: 2 points

Sex (female gender): 1 point

The goal with the CHADS-VASc scoring system is to keep your score as low as possible. If your score is zero blood thinners are not recommended. If your total score is 1 then blood thinners are optional. And if your CHADS-VASc score is 2 or higher the guidelines recommend blood thinners.

Aspirin is Still Important for Other Medical Conditions

While aspirin may not be especially helpful for preventing Afib strokes, it is still used for other conditions. For example, if you have had a stent placed in one of your arteries, then chances are that your physician wants you to take aspirin for the rest of your life. Likewise, if you have had a heart attack or a left atrial appendage occluding device to help prevent AFib strokes, like Watchman, your cardiologist will also probably want you to take aspirin for the rest of your life.

Putting it All Together

The take home message is that aspirin may not prevent AFib strokes but this medication is still used for other reasons. If your CHADS-VASc score is 2 or higher and you can’t take prescription blood thinners for whatever reason, talk to your cardiologist about other options.


The information provided is for general informational purposes only. It is not intended as medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.

About the Photo

The image included in this blog post captures a moment from a recent run I undertook. This stunning run unfolded on a snow-covered trail situated high above Soldier Summit in Utah during the enchanting sunset hours.

Disclaimer Policy: This website is intended to give general information and does not provide medical advice. This website does not create a doctor-patient relationship between you and Dr. John Day. If you have a medical problem, immediately contact your healthcare provider. Information on this website is not intended to diagnose or treat any condition. Dr. John Day is not responsible for any losses, damages or claims that may result from your medical decisions.

  1. Hello Dr. Day,
    I read your comments about blood thinners and cost. I have been using a Canadian pharmacy for some time and the cost savings are unbelievable! For a 90-day supply of generic Xarelto I pay $34.72. Shipping and handling are $9.00. Total for 3 months $43.72. You can get generic Eliquis for roughly the same cost. You are also more than welcome to order Xarelto or Eliquis and still save a bunch of money. I don’t list blood thinner use on my Medicare Prescription plan and save $1400.00 on my yearly payment. I’m curious as to why you wouldn’t recommend Canadian pharmacies to your patients. You can use the website PharmacyChecker.com to get legitimate pharmacies in Canada. ” The People’s Pharmacy” pharmacologist Joe Graedon and medical anthropologist Terry Graedon speak very highly of the Pharmacy Checker website and legitimate pharmacies in Canada. Please get this word out to US citizens.

  2. Having had a pace maker placed isthe risk of a clot if on eloquis the same, less, or increased. Also., if I were to go off Eliquis, with the risk of throwing a clot. Change? Mark.

  3. I am perscribed and take 1 mg of Eliquis 2x per day. This med is costly. Is there a viable alterhative? I am imptressed with Nattokenese. Will it do the job?

  4. Hello Dr. Day,
    I am a follower, bought your book too and watched on your live on line presentation for the Pulse Field Ablation. As far as the blood thinners I had a Watchman done 18 months ago and now only take the low dose aspirin. Do you feel the aspirin is not a good choice post Watchman too?
    7 year afib patient. Thank you.

  5. Is the primary cause of blood clots with those that have afib created by the left atrium appendix? And, if so, does the Watchman resolve that issue, so that no blood thinners are needed, or maybe just an 81mg of aspirin?

    • I had a Watchman installed about a year and a half after a small stroke. I hated Eliquis, didn’t feel right and bruised insanely easy. I was told to take an 81 mg apirin a day after Watchman installed. It messed with my stomach, I knew about nattokinase and blood thinning properties and did research and found it was better than aspirin, plus it has many other health benefits. I am happy with the results. Only drawback is it is not approved by FDA (because it’s a very cheap alternative). Talk to your doc and do research to see what is best for you.
      Best of luck to all.