Should I take blood thinners to control my atrial fibrillation?


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Sharon Reimold, M.D., explains the risks of anticoagulants.

Atrial fibrillation is one of the most common heart problems in the world. Patients with this condition have irregular heartbeats, which, in turn, can lead to the formation of dangerous blood clots that increase the risk of stroke.

In the United States, an estimated 2.6 million people suffer from atrial fibrillation. Research conducted in the United States and Europe has found that one of every four people over 40 years old will develop the condition.

If you have atrial fibrillation – commonly referred to as AFib – it’s important to understand that your greatest risk is having a stroke. Your physician can help you determine your personal risk. It’s also important to ask your physician about the risks and benefits of taking medication for AFib.

Blood thinners have risks and benefits

Many people with AFib are prescribed blood-thinning medication (anticoagulants) to help prevent the formation of blood clots. Before 2010, warfarin (sold under the brand names Coumadin and Jantoven) was the only drug available for AFib patients.

Newer anticoagulant drugs such as dabigatran (Pradaxa), rivaroxaban (Xarelto), apixaban (Eliquis), and edoxaban (Savaysa) have come on the market since then. However, there has been some concern about the bleeding risk of these medications. 

All blood thinners can cause bleeding because they reduce the clotting effects of the blood. Multiple studies have examined the bleeding risks associated with Pradaxa, Xarelto, and other new blood thinners, and research is continuing.

Pradaxa carries a higher risk of gastrointestinal bleeding than warfarin for people over age 65, but it also is more effective at reducing the risk of stroke and death, according to a 2014 study from the U.S. Food and Drug Administration (FDA). The FDA determined that Pradaxa has a “favorable benefit to risk profile” and made no changes to usage recommendations. There is, likewise, a concern that Xarelto may be associated with an increased risk of gastrointestinal bleeding.

In addition to the effects of medication, we also know that age plays a role in your risk for bleeding. A 2015 study found that the risk of gastrointestinal bleeding was similar when comparing warfarin to newer blood thinners in patients 65 and younger. However, the study also found that the bleeding risk increases after age 65 – and especially after age 75.

Despite the risks, newer blood thinners offer some benefits over warfarin:

  • Patients who take warfarin are required to test their blood thickness monthly.
  • People taking warfarin must also avoid consuming foods with vitamin K – too much can reduce the effectiveness of the medication.
  • Warfarin has no standard dosage level. Recommended dosage varies depending on a person’s age, diet, and other medications.

None of these are a concern for people who take the newer agents, which are dosed according to age and underlying kidney function.

How doctors determine if you should take blood thinners

Patient preference is now a bigger factor than ever before in how we treat AFib. Every patient has different concerns, and we take those into consideration.

For example, if one of your relatives has had a stroke, you may be afraid of having one, too. A 1 percent chance of stroke may be enough for you to want to take blood thinners. On the other hand, you may have a 4 percent risk of stroke but have had a bleeding incident in the past, so you may not be in favor of taking blood thinners.

It’s my responsibility as a cardiologist to explain your risks and benefits with each medication and help you make the best treatment decision for you. To help guide my recommendations, I’ll calculate two scores for you:

  • The CHA2DS2-VASc score measures your risk of stroke. Your blood pressure, age, and history of stroke and heart failure are all taken into account.
  • The HAS-BLED score measures your bleeding risk. We look at your history of liver disease, kidney disease, low blood platelet counts, and other factors.

If you have AFib, ask your doctor what your CHA2DS2-VASc and HAS-BLED scores are and what that means for you personally. We can walk you through these types of decisions. To learn more, request an appointment online or call 214-645-8300.