A new class of blood thinners and two new devices lower the high risk of stroke in people with atrial fibrillation (AFib). Duke doctors were involved in several of the studies that led to FDA approval for two of the new drugs, and are among the first in the region to offer the new devices to people with atrial fibrillation.
Only 50% of AFib Patients on Medication to Prevent Stroke
Nearly three million people in the U.S. have atrial fibrillation, and their risk for stroke is five times higher than people without the heart rhythm disorder. That’s because the rapid, irregular heartbeats that define atrial fibrillation can cause blood clots to form, which lead to stroke.
Warfarin (Coumadin), is often prescribed to lower stroke risk in these people because it reduces the blood's tendency to form clots. This is commonly referred to as “thinning” the blood, explained James Daubert, MD, a heart rhythm specialist at Duke. However, frequent blood tests are needed to determine if the drug is making the blood too thin – which can lead to serious bleeding risks including bleeding in the brain – or too thick, which can cause stroke. Diet is a concern too, as vitamin K, found in green leafy vegetables, inhibits the drug’s effectiveness. These issues make some doctors hesitant to prescribe warfarin, and some people unwilling to take it.
“Only about half of patients with atrial fibrillation who should be on an anticoagulant are on such medications to prevent stroke,” said Dr. Daubert.
Safer, More Effective Anticoagulants
Recently, the FDA approved several new stroke-prevention drugs in a new class of drugs called novel oral anticoagulants (NOACs). They’ve proven to be a safer alternative, while doing as good or better job at reducing stroke risk in people with atrial fibrillation. They consistently thin the blood, and there are no dietary restrictions. However, there is currently no way to reverse the effects of the medication, and that makes some doctors cautious about recommending them to their patients.
That’s not the case at Duke, where doctors were the principal investigators of the clinical studies for two of the four new anticoagulants – rivaroxaban (Xarelto) and apixaban (Eliquis). As a result, Dr. Daubert explained, “We’re more aggressive about recommending these anticoagulants and more knowledgeable about the real risks and benefits. We have a lot of experience understanding the issues and managing the patients.”
New Devices Prevent Blood Clots from Forming
Two new devices – called left atrial appendage occlusion devices -- can protect against stroke in patients unable to safely take anticoagulants long term. The atrium is one of the two areas of the heart where blood collects. “The left atrial appendage is like a little cul de sac off the left atrium,” Dr. Daubert explained. “When you are in atrial fibrillation, and the atrium isn’t vigorously contracting, blood can stagnate and form a clot which can cause a stroke." These devices block the left atrial appendage and prevent clots from escaping.
One device, called the Lariat, uses a lasso-type tip to close-off the neck or opening of the left atrial appendage. It is implanted by an interventional electrophysiologist who inserts catheters through small incisions in the groin and under the breastbone to position the device around the left atrial appendage. Heart rhythm specialist Kevin Jackson, MD, recently performed the first Lariat procedure at Duke.
The second device, called the Watchman, relies on a parachute-type device to block the opening of the left atrial appendage. It was recently approved by the FDA and is only available at a handful of heart centers. Duke was the first North Carolina hospital to implant the device and is now offering it as a treatment option.
“These procedures could help address the risk of stroke in the substantial portion of patients with atrial fibrillation who are either not taking, or are not good candidates, or are at high risk for continual anticoagulation therapy,” Dr. Daubert said.