MONDAY, May 17, 2021 (HealthDay News) -- A simple surgery may help lower the risk for strokes by more than a third in patients with atrial fibrillation, a common irregular heartbeat, a new trial finds.
The reduction in stroke risk is achieved by blocking the left atrial appendage, an unused, finger-like tissue that traps blood in the upper chamber of the heart and increases the risk of clots that can cause strokes, the researchers explained.
"This study was performed in patients who were already undergoing heart surgery for other indications, so it was basically the addition of a secondary procedure," said lead researcher Dr. Richard Whitlock, a professor of surgery at McMaster University in Hamilton, Ontario, Canada.
As with most patients with atrial fibrillation, patients in this study were already taking blood thinners to prevent stroke.
This study supports this procedure of removal and closure (occlusion) of the left atrial appendage while doing heart surgery. But patients will still need to take blood thinners after the operation, Whitlock noted.
The combination of the surgery plus continuing to take blood thinners is how the additional protection from stroke is achieved, he added.
Removing the left atrial appendage does not affect how the heart functions, and the procedure is safe with no side effects, Whitlock said.
"This appendage is left over from how the heart forms when you're developing in the womb," he said. "It is not a vital factor, but happens to be quite harmful when you develop atrial fibrillation."
For the study, researchers tracked nearly 4,800 people in 27 countries who had atrial fibrillation and were taking blood thinners. They were an average age of 71.
When these patients were undergoing cardiac bypass surgery, they were randomly selected to have their left atrial appendage removed or not. Patients were followed for a median of four years.
Dr. Gregg Fonarow, interim chief of the division of cardiology at the University of California, Los Angeles, and director of the Ahmanson-UCLA Cardiomyopathy Center, believes this procedure is a breakthrough in the treatment of atrial fibrillation.
"Atrial fibrillation is associated with a three- to fivefold increased risk of stroke," he said.
For patients having cardiac surgery, removing the left atrial appendage was hypothesized to help lower the risk of stroke, even among patients being treated with blood thinners, Fonarow said.
Previously, however, no large-scale clinical trials have tested this hypothesis, and other studies have had mixed results. Also, guidelines have not provided definitive recommendations, he said.
This large trial provides compelling findings that among patients with atrial fibrillation undergoing cardiac surgery, removing the left atrial appendage significantly lowers the risk of stroke when the majority continued to be treated with blood thinners, Fonarow said.
"These results should be practice-changing," he said. "It is important to recognize that these findings apply to surgical left atrial appendage occlusion when added to oral anticoagulation [blood thinners]. Whether less invasive approaches to left atrial appendage removal are safe and effective when added to oral anticoagulation requires formal study."
Whitlock agreed that it's not known whether this procedure will benefit patients with atrial fibrillation not already having cardiac surgery.
"This opens up a new paradigm that needs to be further investigated in non-cardiac surgery patients, but it's a new paradigm of stroke prevention in atrial fibrillation," he said.
Whitlock hopes that trials will be done testing whether the procedure reduces the risk of stroke in all patients with atrial fibrillation.
One expert, however, doesn't consider these findings the end of the discussion about the benefit of the procedure.
"Although I would not characterize this as a breakthrough, it does provide high-quality data supporting left atrial appendage occlusion at the time of cardiac surgery in patients who have atrial fibrillation," said Dr. Larry Goldstein, chairman of the department of neurology at the University of Kentucky.
"It is important to note that the study does not support performing heart surgery for this purpose, and because it did not compare left atrial appendage removal with anticoagulation alone, it did not determine whether left atrial appendage surgery can replace oral blood thinners," Goldstein said.
The study results were published May 15 in the New England Journal of Medicine, to coincide with a presentation at the American College of Cardiology virtual annual meeting.
For more on atrial fibrillation, see the American Heart Association.
SOURCES: Richard Whitlock, MD, PhD, professor, surgery, McMaster University, Hamilton, Ontario, Canada; Gregg Fonarow, MD, interim chief, division of cardiology, University of California, Los Angeles, and director, Ahmanson-UCLA Cardiomyopathy Center; Larry Goldstein, MD, professor and chairman, department of neurology, University of Kentucky, Lexington; New England Journal of Medicine, May 15, 2021; American College of Cardiology virtual annual meeting, presentation, May 15, 2021