Atrial Fibrillation: Are You Getting the Right Treatment to Prevent a Stroke?

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If you knew you were at high risk for a stroke and that a drug might be able to prevent it, would you take that medicine? Anticoagulant drugs that help prevent the formation of blood clots can significantly lower stroke risk in people with atrial fibrillation (AFib), a common irregular heart rhythm. Yet most people with AFib either receive no anticoagulant therapy or are prescribed an inadequate dosage to prevent a stroke, a large study finds.

The stroke risk in patients with AFib is up to seven times that of the general public-and the incidence of stroke attributable to AFib increases with age, most dramatically after age 80. Upwards of 24 percent of all ischemic strokes-which make up about 85 percent of all forms of strokes-are due to AFib. Moreover, strokes related to AFib are often major strokes that have worse outcomes than non-AFib strokes, with a greater likelihood of significant disability or death.

The power of anticoagulants

Studies show that people with AFib can cut the risk of having a stroke by more than two-thirds, as well as reduce a stroke’s severity, by taking anticoagulants. Anticoagulants include the vitamin K antagonist warfarin (Coumadin, Jantovin) and the newer non-vitamin K antagonist oral anticoagulants (NOACs) apixaban (Eliquis), dabigatran (Pradaxa), edoxaban (Savaysa), and rivaroxaban (Xarelto).

Treatment guidelines recommend that high-risk patients with AFib use one of these drugs to reduce their stroke risk. Yet a study led by researchers at Duke University Medical Center found that anticoagulants are seriously underused by older adults. The researchers reviewed the medical data of almost 95,000 patients (average age, 80) with a history of AFib who were hospitalized for stroke.

Nearly 84 percent of the patients were either not using anticoagulants or not taking the guideline-recommended therapeutic dose before their stroke, according to the study results published in 2017 in the Journal of the American Medical Association. Use of anticoagulation therapy was associated with lower odds of moderate to severe strokes and deaths from strokes among patients admitted to the hospital. It wasn’t entirely clear to the researchers why the patients hadn’t followed the recommended anticoagulant regimen prestroke. Two-thirds of the patient records had no documented reason for skipping anticoagulation. Some data showed that common reasons for not starting anticoagulation after a stroke included a high bleeding or fall risk (which could lead to dangerous bleeding), serious side effects, a warfarin allergy, and refusal by patients or their families to take the drug.

Previous studies have similarly found that anticoagulants are inadequately used in people with AFib. A 2016 study in the Journal of the American College of Cardiology (JACC) looked at 295,000 patients with AFib who were candidates for anticoagulants based on their stroke risk scores. Only about 60 percent were on those medicines. The other 40 percent were on aspirin therapy alone, even though warfarin and NOACs are known to be more effective than aspirin in preventing strokes in people with AFib.

Consult your doctor

If you have AFib and you aren’t taking an anticoagulant, ask your doctor why-and whether you might be a good candidate for the drug based on your stroke risk. If you begin anticoagulation therapy, schedule regular follow-up visits with your doctor to make sure the drug is working for you. Never stop taking the drug or adjust the dose without first checking with your doctor. Be watchful for side effects like bleeding, and report them to your doctor if you have them. Signs of unusual bleeding include prolonged bleeding from cuts, nosebleeds, bleeding gums when you brush your teeth, easy bleeding or blood blisters, red or dark brown urine, red or black stools, coughing up blood, severe headache, dizziness, and weakness.