By Jon Kamp
Of DOW JONES NEWSWIRES
ORLANDO, Fla. (Dow Jones)--A device that blocks off a heart area where clots often form can better protect patients at risk of stroke due to a common heart-rhythm disorder than a widely used anti-clotting drug, according to a study released Saturday.
The results, which were presented at the American College of Cardiology's annual conference, may influence how patients at risk of strokes from the rhythm disorder atrial fibrillation are commonly treated. The device triggered some complications when implanted, such as fluid around the heart, but patients with it had lower complication rates over time.
The device in question, called "Watchman," is made by privately held Atritech Inc. of Plymouth, Minn., which sponsored the $50 million "Protect AF" study and has already filed an application seeking Food and Drug Administration approval. The study was designed to see whether the device could do better than Warfarin, an anticoagulant sold under the brand-name Coumadin by Bristol-Myers Squibb Co. (BMY).
Atrial fibrillation patients are frequently prescribed Warfarin to help guard against strokes, because quivering in the heart's upper chambers - the hallmark of the rhythm disorder - can allow blood to pool and clot. Warfarin helps, but also poses a risk of serious bleeding for some patients.
David Holmes, a cardiologist from the Mayo Clinic who served as the study's principal investigator, noted during a press conference that one in four people over the age of 40 have the rhythm disorder, including more than three million people in the U.S.
The Watchman device is threaded into place with a catheter inserted in a leg vein and it blocks clots that often form in an area called the left atrial appendage.
The Protect AF study included 707 patients with a type of the rhythm disorder known as non-valvular atrial fibrillation, which means they don't also have heart-valve problems. Among them, 463 patients got the device and stopped taking Warfarin - most were off the drug within 45 days - while 244 patients were treated with the drug long-term.
After totaling up time spent by patients in the study, researchers used more than 900 "patient years" of data to determine the following: There was about a 30% reduction in the risk of cardiovascular death and stroke when patients had the device. Regarding a particularly dangerous type of stroke called Hemorrhagic strokes, there were six events that killed four patients in the drug group and one none-fatal event in the device group.
There was an 8.7% rate of procedure-related complications in the device group, but in comparing complications after Warfarin treatment was stopped in the other group, the rates were lower among device patients. Holmes noted that complication rates with the device got better over time, suggesting doctors improved their technique.
Cardiologists said ahead of the data release that a successful study could have a big impact on how these patients are treated. There is also a burgeoning market for curing atrial fibrillation by using devices to burn or freeze tissue and disengage electrical signals responsible for the problem, but many patients won't have the procedure and will need to manage their stroke risk.
"If that study is positive, I think it could open some avenues for interventionalists," said Dr. Martin Leon, an interventional cardiologist and professor of medicine at Columbia University Medical Center, in an interview ahead of the study release. Interventional cardiologists perform angioplasty and would also implant the Watchman device.
Jim Bullock, Atritech's chief executive, noted that the idea for Watchman came from surgery that has been done for decades to close off the pouch in question. But this is a very invasive procedure that was typically done when some other type of open-heart surgery was already planned. His company worked for years on this less-invasive approach.
The FDA has scheduled a panel of experts to review the device in late April.
-By Jon Kamp, Dow Jones Newswires; 617-654-6728; jon.kamp@dowjones.com
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