Physician, patient and daughter in hospital room

Beyond Blood Thinners

A one-time procedure that may reduce stroke risk for a lifetime.
"The blood thinner he was on was contributing to his excessive internal bleeding"

Pat, wife of Billy Stacy, WATCHMAN recipient

What are the treatment options to reduce stroke risk if you have AF?

There are different treatments available to reduce your stroke risk if you have AF. The most common treatment to reduce AF-related stroke risk is using blood thinner medications.


Blood Thinner Medications and AF Stroke Risk

Blood thinner medications, also called anticoagulant drugs (OACs), are an effective way to lower the risk of blood clots and stroke in people with atrial fibrillation, or AF, not caused by a heart valve problem.1


Oral anticoagulants

The most common treatment for managing AF-related stroke risk is the use of anticoagulants, such as vitamin K antagonist (VKA) and novel oral anticoagulants (NOACs).

Warfarin and NOACs effectively reduce the risk of cardioembolic stroke, however they are not well tolerated by some patients and carry a risk for bleeding complications.

The limitations of oral anticoagulants include:

  • Risk of bleeding 
  • High rate of discontinuation (at 2 years, 50% of patients on warfarin and 30% on NOAC treatment)
  • Interactions with certain foods and medications (warfarin) 
  • Frequent blood tests and dose adjustement (warfarin)


Blood Thinner Medications and Bleeding Risks

Blood thinners, or anticoagulants, are very effective at reducing the risk of stroke in people with atrial fibrillation, and most people can take them for years without serious side effects. But because blood thinners help prevent clots by thinning the blood, they also increase the risk of bleeding.1

Minor bleeding: Most bleeding events are minor and easily treated, like a cut taking longer than normal to stop bleeding. Some people bruise more easily on blood thinners. You should discuss any of these symptoms with your doctor.

Major bleeding: In other cases, bleeding can be serious and require medical help or blood transfusions. Sometimes, the bleeding can be life-threatening, for example, when bleeding in the brain causes a stroke.

When considering your treatment options, your cardiologist will weigh your risk of a stroke against your risk of a serious bleeding problem. These risks depend on several factors—for some people the risk of bleeding is higher than for others.1


Anticoagulant Drugs vs Antiplatelet Drugs

Both antiplatelet and anticoagulant medicines work to reduce the risk of stroke by preventing blood clots from forming. Here’s how they differ3:

  • Anticoagulants (also called blood thinners) prevent clots from forming by acting upon certain proteins in the blood that are necessary to the clotting process
  • Antiplatelets, like aspirin and clopidogrel, keep platelets in the blood from sticking together; platelets play a role in helping the blood to clot

Anticoagulant drugs are more powerful than antiplatelet drugs. They are also associated with more serious side effects than antiplatelets. Anticoagulants are typically used for people at higher risk for stroke due to age, sex, history of blood clots, and other health conditions.3

blood clot in left atrial appendage illustration

If You Can’t Take a Blood Thinner Long Term because You Are at Risk of Recurrent Bleeding or contraindicated to Oral Anticoagulation (OAC)

Some people with Atrial Fibrillation at high risk of stroke who should take Oral Anticoagulants are either unable or unwilling to take them because of associated risks, side effects or medical reasons, that could also result in a high risk for bleedings.4

Left atrial appendage closure: A procedure called left atrial appendage closure provides an alternative to warfarin for people who need one. The left atrial appendage is a small pouch at the top of the heart. When a blood clot escapes from the left atrial appendage and travels to another part of the body, it can cut off the blood supply to the brain, causing a stroke.5

The WATCHMAN FLX Implant: In people with AF not caused by a heart valve problem, more than 90% of stroke-causing clots that come from the heart are formed in the left atrial appendage (LAA).6 Closing off the LAA is an effective way to reduce stroke risk in these people. This is how the WATCHMAN FLX Implant works.7

It’s important to understand that a stroke can be caused by factors other than a clot escaping from the left atrial appendage. These causes can include high blood pressure and the narrowing of blood vessels to the brain.3 Left atrial appendage closure will not prevent these other causes of stroke.

Learn more about the WATCHMAN FLX procedure

How Is WATCHMAN FLX an Alternative to Oral Anticoagulants?

WATCHMAN FLX is a permanent heart implant that may replace the need for long-term blood thinners. WATCHMAN was compared to warfarin in clinical trials and was found to effectively reduce the risk of stroke.8

WATCHMAN FLX may be right for you if:

  • You have non-valvular AF, a high risk of stroke and:
    • If you are contraindicated or intolerant to oral anticoagulants (OAC)9 
    • If you have a high risk of bleeding or history of bleeding10
    • If you have had a stroke or Transient Ischemic Attack in the past

It’s important to understand that, like blood thinners, WATCHMAN FLX does not cure AF.

Learn more about WATCHMAN as an alternative to warfarin

WATCHMAN device illustration

WATCHMAN FLX closes off the left atrial appendage to reduce the risk of stroke

The WATCHMAN FLX Difference

In a one-time procedure, WATCHMAN FLX reduces the risk of stroke without the risk of bleeding that comes with long-term oral anticoagulants use.8,11


Questions to Ask Your Doctor

If you have Atrial Fibrillation not caused by a heart valve problem and need an alternative to Oral Anticoagulants, here are some questions to ask your cardiologist:

  • What Oral Anticoagulants substitutes are available to me?
  • What are the risks and benefits of the different blood thinners?
  • Am I within the recommended blood clotting range on warfarin?
  • Does my lifestyle or health history put me at risk for serious bleeding?
  • Am I a candidate for left atrial appendage closure?
  • What should I know about the WATCHMAN FLX Implant?

If you think WATCHMAN FLX could be right for you, answer a few questions and get a personalized guide for talking to your cardiologist.

Answer a few questions and get a customized guide


WATCHMAN FLX reduces the risk of stroke and the long term risk of bleeding associated with OAC use in patients with non-valvular AF.8


WATCHMAN FLX is for people with atrial fibrillation not caused by a heart valve problem who need an alternative to oral anticoagulants. This website is intended to provide patients and caregivers with some information about the WATCHMAN FLX Implant. It may help prepare you for talking to your doctor about your options for reducing stroke risk.

CAUTION: The law restricts these devices to sale by or on the order of a physician. Indications, contraindications, warnings and instructions for use can be found in the product labeling supplied with each device. Information for the use only in countries with applicable health authority product registrations.

Content of this website is for Information Purposes only and not meant for product promotion or medical diagnostic. This information does not constitute medical or legal advice, and BSC makes no representation or warranty regarding this information or its completeness, accuracy or timeliness.

Accordingly, BSC strongly recommends that you consult with your physician on all matters pertaining to your health or to address any questions.


  1. National Stroke Association. Making the Afib-Stroke Connection. Published 2012. Accessed September 1, 2016. 
  2. Martinez et al. Thromb Haemost 2015;114: In press. 
  3. American Stroke Association website. American Heart Association. Published 2017. Accessed May 31, 2017. 
  4. Tzikas A, et al. EuroIntervention. 2016 May 17;12(1):103-11. 
  5. Cleveland Clinic. Atrial fibrillation (Afib). Published May 2015. Accessed August 25, 2016. 
  6. Blackshear JL, Odell JA. Appendage obliteration to reduce stroke in cardiac surgical patients with atrial fibrillation. Ann Thorac Surg. 1996;61:755-759. 
  7. Holmes DR Jr, Kar S, Price MJ, et al. Prospective randomized evaluation of the Watchman Left Atrial Appendage Closure device in patients with atrial fibrillation versus long-term warfarin therapy: the PREVAIL trial. J Am Coll Cardiol. 2014;64(1):1-12. 
  8. Holmes DR Jr, Doshi SK, Kar S, et al. Left atrial appendage closure as an alternative to warfarin for stroke prevention in atrial fibrillation: a patient-level meta-analysis. J Am Coll Cardiol. 2015;65(24):2614-2623. 
  9. For contraindications, refer to Instructions for use of anticoagulant drugs. NOACs (dabigatran, rivaroxaban, and apixaban) are not recommended in patients with severe renal impairment (CrCl <30 mL/min) - ESC guideline 2016. 
  10. 2012 focused update of the ESC Guidelines for the management of atrial fibrillation. Camm AJ et al. European Heart Journal 2012;33:2719-2747. 
  11. Price MJ, Reddy VY, Valderrábano M, et al. Bleeding outcomes after left atrial appendage closure compared with long-term warfarin. JACC Cardiovasc Interv. 2015;8(15):1925-1932.