People
with atrial fibrillation have a sixfold increased risk of stroke, the
researchers noted, and typically need to take warfarin for the rest of
their lives. Atrial fibrillation is a common heart rhythm problem that
causes the upper chamber of the heart to beat irregularly.
"One in four people over 50 will develop atrial fibrillation," lead
researcher Dr. David R. Holmes Jr., the Scripps Professor of Medicine
at the Mayo Graduate School of Medicine, said during a morning
teleconference at the American College of Cardiology annual meeting
Saturday in Orlando, Fla.
About 3 million people in the United States have atrial fibrillation,
and 16 million Americans will have the condition by 2050, Holmes said.
Stroke is the most serious complication related to atrial fibrillation,
he noted.
"We know that in those patients with atrial fibrillation that the clot
that causes that stroke comes from a certain area of the heart called
the left atrial appendage," Holmes said, explaining that the appendage
is a muscular pouch connected to the left atrium. "The device isolates
the left atrial appendage."
To implant the device, an interventional cardiologist uses a catheter
inserted in a leg vein to guide the device into the heart; the device
travels through the heart's right chamber and is deposited into the
left atrium through a puncture hole between the two chambers of the
heart, the researchers explained.
Current treatment with warfarin is effective in preventing strokes
caused by clots associated with atrial fibrillation, but its use needs
to be monitored monthly to assure patients are receiving the safest and
most effective dose because it can cause serious bleeding if given in
doses that are too high, Holmes noted.
In the Embolic Protection in Patients With Atrial Fibrillation (PROTECT
AF) trial, researchers compared treatment with warfarin to a
fabric-covered, expandable cage called the WATCHMAN. The device blocks
blood clots that typically form in the heart's left atrial appendage.
The 707 patients were randomly assigned to one of the two treatments.
"Efficacy was dramatically better with the device, and stopping the warfarin," Holmes said.
The researchers found that patients with the WATCHMAN had a 32 percent
lower risk of stroke and cardiovascular death compared with warfarin
therapy. This was especially true for hemorrhagic stroke, which causes
bleeding in the brain and is usually fatal, Holmes noted.
In addition, there were fewer complications with the device, once it
was implanted, compared to warfarin. Most complications with the device
occurred when placing it in the heart, but these complications now
occur in only 1 percent of patients, Holmes noted.
The researchers concluded that the device is an effective alternative
to warfarin for preventing stroke in patients with atrial fibrillation,
particularly those at the highest risk of stroke.
"A strategy like this can be used in patients with non-valvular atrial
fibrillation to prevent stroke, and get them off warfarin," Holmes said.
Dr. Gregg C. Fonarow, professor of cardiology at the University of
California, Los Angeles, thinks this device will benefit many patients
with atrial fibrillation.
"The major risk of atrial fibrillation is blood clots forming in the
heart, and then breaking loose to cause stroke. Most of these blood
clots form in the appendage of the left atrium," Fonarow said.
The only effective treatment until now was lifelong use of warfarin.
Researchers have been searching for alternative therapies to warfarin
to protect patients with atrial fibrillation from stroke without
success for decades, Fonarow noted.
"The findings from this clinical trial are very impressive," Fonarow
said. "Although there were some procedure-related complications,
treatment with this novel device will be very attractive and provide
patients with atrial fibrillation effective, long-term protection from
stroke and systemic embolization without the bleeding risks associated
with warfarin."
with atrial fibrillation have a sixfold increased risk of stroke, the
researchers noted, and typically need to take warfarin for the rest of
their lives. Atrial fibrillation is a common heart rhythm problem that
causes the upper chamber of the heart to beat irregularly.
"One in four people over 50 will develop atrial fibrillation," lead
researcher Dr. David R. Holmes Jr., the Scripps Professor of Medicine
at the Mayo Graduate School of Medicine, said during a morning
teleconference at the American College of Cardiology annual meeting
Saturday in Orlando, Fla.
About 3 million people in the United States have atrial fibrillation,
and 16 million Americans will have the condition by 2050, Holmes said.
Stroke is the most serious complication related to atrial fibrillation,
he noted.
"We know that in those patients with atrial fibrillation that the clot
that causes that stroke comes from a certain area of the heart called
the left atrial appendage," Holmes said, explaining that the appendage
is a muscular pouch connected to the left atrium. "The device isolates
the left atrial appendage."
To implant the device, an interventional cardiologist uses a catheter
inserted in a leg vein to guide the device into the heart; the device
travels through the heart's right chamber and is deposited into the
left atrium through a puncture hole between the two chambers of the
heart, the researchers explained.
Current treatment with warfarin is effective in preventing strokes
caused by clots associated with atrial fibrillation, but its use needs
to be monitored monthly to assure patients are receiving the safest and
most effective dose because it can cause serious bleeding if given in
doses that are too high, Holmes noted.
In the Embolic Protection in Patients With Atrial Fibrillation (PROTECT
AF) trial, researchers compared treatment with warfarin to a
fabric-covered, expandable cage called the WATCHMAN. The device blocks
blood clots that typically form in the heart's left atrial appendage.
The 707 patients were randomly assigned to one of the two treatments.
"Efficacy was dramatically better with the device, and stopping the warfarin," Holmes said.
The researchers found that patients with the WATCHMAN had a 32 percent
lower risk of stroke and cardiovascular death compared with warfarin
therapy. This was especially true for hemorrhagic stroke, which causes
bleeding in the brain and is usually fatal, Holmes noted.
In addition, there were fewer complications with the device, once it
was implanted, compared to warfarin. Most complications with the device
occurred when placing it in the heart, but these complications now
occur in only 1 percent of patients, Holmes noted.
The researchers concluded that the device is an effective alternative
to warfarin for preventing stroke in patients with atrial fibrillation,
particularly those at the highest risk of stroke.
"A strategy like this can be used in patients with non-valvular atrial
fibrillation to prevent stroke, and get them off warfarin," Holmes said.
Dr. Gregg C. Fonarow, professor of cardiology at the University of
California, Los Angeles, thinks this device will benefit many patients
with atrial fibrillation.
"The major risk of atrial fibrillation is blood clots forming in the
heart, and then breaking loose to cause stroke. Most of these blood
clots form in the appendage of the left atrium," Fonarow said.
The only effective treatment until now was lifelong use of warfarin.
Researchers have been searching for alternative therapies to warfarin
to protect patients with atrial fibrillation from stroke without
success for decades, Fonarow noted.
"The findings from this clinical trial are very impressive," Fonarow
said. "Although there were some procedure-related complications,
treatment with this novel device will be very attractive and provide
patients with atrial fibrillation effective, long-term protection from
stroke and systemic embolization without the bleeding risks associated
with warfarin."
