WATCHMAN® LAA Closure Device Image courtesy of Atritech, Inc. Plymouth, MN.
It looks like a tiny parachute or net, but this small medical device could lead to big improvements in the care of patients with atrial fibrillation (AF). The Massachusetts General Hospital Heart Center is part of the study evaluating the effectiveness of this device, called the Watchman, which shows promise in preventing the occurrence of stroke among patients with AF.
"Atrial fibrillation is an epidemic along with obesity and diabetes. As the population ages, the prevalence of AF will also continue to rise," said Moussa Mansour, MD, a cardiologist with the Heart Center’s Cardiac Arrhythmia Service and director of the Electrophysiology Laboratory. "The Watchman provides a safe, effective alternative to better manage the stroke risk for these patients."
Atrial fibrillation is the most common form of irregular heartbeat, affecting more than 2.2 million people in the United States. AF causes the upper chambers of the heart to beat too fast, inhibiting the movement of blood in and out of the heart. This irregularity can cause blood to pool and form clots in an area of the heart called the left atrial appendage. These clots have the potential to break loose and travel to the brain, resulting in a stroke.
Because of the stroke risk, AF patients are prescribed blood thinning medications, such as warfarin (also known by the brand name Coumadin), to prevent the formation of clots. These drugs can have unpleasant and even dangerous side effects, such as bruising and internal bleeding. Patients taking them also require frequent visits to their doctors for blood tests, as often as once per week.
Watch a video of the Watchman at work
"Taking blood thinners requires constant monitoring by doctors to ensure the correct level of drugs in the patient’s system. These drugs also impose limitations on a patient’s diet, physical activity and travel," said Mansour.
Ann Webster, 74, is familiar with these risks and restrictions. Webster had been taking Coumadin for five years and had several complications with the medication during that time.
"I had a spinal bleed that was causing terrible pain in my shoulder," said Webster, who has some persistent problems for this bleed.
Webster’s husband, John, also had AF and was taking blood thinners as well.
"We had to get blood tests all the time. At least every six weeks, sometimes it was every other week or even weekly when there were problems regulating the levels in my system," she said.
After experiencing an irregular heartbeat due to his AF, John’s cardiologist referred him to Dr. Mansour at Mass General to be evaluated for a new procedure being studied. Ann had read about the Watchman procedure and was excited to learn about its potential for her husband, and after the appointment Dr. Mansour determined he was a good candidate for this treatment.
During the procedure, the Watchman device is implanted in the heart through a catheter that follows the patient’s circulatory system up from the groin. The device is positioned at the opening to the heart’s left atrial appendage. In patients with AF, blood sometimes pools in this area and forms clots. This device captures those clots and prevents them from entering the bloodstream.
John Webster came into Mass General on October 30, 2009, for the procedure, which lasted less than three hours. Ann was so impressed with the ease of the procedure she immediately made arrangements to have the Watchman implanted in her heart as well. After determining she was a candidate, Dr. Mansour implanted her on November 9.
"The procedure was really no problem," she explained. "Neither of us had any difficulty with it. The biggest inconvenience was not being able to drive for a few days."
Since their procedures, both Ann and John have been able to discontinue their Coumadin prescriptions.
"Patients have to continue on their blood thinning medications for about 45 days to be sure the Watchman has created a complete seal of the left atrial appendage. After that, patient will have no restrictions on their physical activities or food choices related to their AF. No more worries," said Mansour.
The study that evaluated the Watchman device, PROTECT AF, was published last year in the medical journal Lancet and found the procedure was as effective as blood thinners in preventing stroke in AF patients. Based on these finding, in April 2009, an FDA Advisory Panel recommended the device be approved for use in patients with AF. A full FDA approval of the device, which is already widely used in Europe, is expected this year.
"This device has the potential to revolutionize the way we deal with atrial fibrillation," said Jeremy Ruskin, MD, director of the Heart Center’s Cardiac Arrhythmia Service. "Our early involvement in this study has allowed Mass General to be at the forefront of this important research."