An experimental treatment
used to clear clogged neck arteries carries a higher-than-expected risk of
stroke and death, according to a study that was stopped early for safety
reasons.
The study compared the use of stents, small tubes that prop open blood
vessels with a common surgical procedure for cleaning out blockages in the
carotid artery. Deaths and strokes were more than twice as common in patients
treated with stents, the researchers found.
The findings conflict with influential earlier research, which found stents
to be safer.
"The jury is still out," said Dr. Anthony Furlan, a vascular neurologist at
the Cleveland Clinic.
Furlan wrote an editorial that accompanies the new study, published in
Thursday's New England Journal of Medicine.
At issue is the best way to treat patients who develop blockages in the
carotid, a key artery that supplies blood to the brain. The blockages are caused
by plaque, a cheesy buildup of fat and cholesterol.
Many people with partial blockages do not experience symptoms. But the
condition can cause a mini-stroke with temporary symptoms such as loss or
blurring of vision in one eye, or weakness or numbness in an arm or leg. If left
untreated, a blockage can lead to a major stroke or death.
In the standard treatment, doctors clamp off the artery and clean it out
surgically. But that can be risky, especially for patients with heart damage or
problems in the other carotid artery.
Doctors developed another treatment, in which they use a catheter to string a
wire mesh stent into the artery that expands and props the artery open.
U.S. doctors have been doing carotid stenting since the mid-1990s. But the
Food and Drug Administration has approved stenting only in patients who have
symptoms from an artery that is blocked 70 percent or more and for whom surgery
would be highly risky.
In the new study, French researchers recruited adult patients who had
symptoms, a 60 percent or more blockage of the carotid artery, and an average
surgery risk. Of the 520 participants, half got surgery and half got stents.
A month after undergoing the procedures, nearly 10 percent of the stented
patients suffered death or stroke, versus only 4 percent of the surgical
patients.
Here are the numbers: In the stent group, two people died and 23 others
suffered a stroke. In the surgical group, three died and seven more suffered
stroke.
In contrast, a 2004 U.S. study of patients with high surgery risk found the
incidence of death, stroke or heart attack was about 5.5 percent in patients
treated with a stent and 10 percent in patients treated with surgery. The
difference was attributed to fewer heart attacks in the stent patients.
Some doctors criticized the new study. They noted that initially, the
physicians who placed stents did not use an umbrella-like device that is placed
beyond the blockage to catch any plaque that breaks off. The 2004 study used the
devices.
U.S. standards require use of the device, said Dr. Christopher Cates, an
Emory University cardiologist who has performed more than 600 carotid stent
procedures.
The researchers strengthened safety guidelines after the study was under way
to include the devices, but strokes and deaths had already occurred, Cates said.
"That may have been the difference," he said.
The French study also allowed physicians to use a range of different stents,
and doctors were not required to have worked with individual products more than
twice before, Cates and others said.
A U.S. government-funded study now under way has enrolled 1,472 people. It
requires a cerebral protection system and more physician training with the stent
used.
"That's our best hope for a more definitive answer," Furlan
said.
