Should Carotid Patients Skip Surgery?
Medication Often Enough to Treat Asymptomatic Carotid Stenosis, Study Shows
Sept. 25, 2008 -- Surgery or stenting is not necessary for at least 95% of
patients with a condition called asymptomatic carotid stenosis (ACS), says a
team of researchers from Canada and Greece.
ACS is a condition in which the main vessels supplying blood to the brain
are narrowed but the patient has no stroke symptoms.
More intense medical treatment with cholesterol-lowering and blood-thinning
drugs has lowered the risk of stroke in these patients by reducing the number
of tiny blood clots or plaque chunks (called microemboli) that break off from
the artery and travel to the brain, says lead author J. David Spence, MD, a
neurologist at The University of Western Ontario in London, Ontario,
Narrowing of the carotid vessels is considered a risk factor for stroke. But
doctors have long debated whether those who have narrowing but no symptoms --
such as strokes or mini-strokes (also called transient ischemic attacks or
TIAs) -- should have surgery to remove the plaque or undergo placement of
stents to open the vessel.
Such interventions are probably overused, Spence tells WebMD, because the
risk of surgery or stenting to prevent stroke could actually be greater than
the risk of having a stroke in certain patients.
"So the message is that now less than 5% of patients with ACS tend to
benefit from surgery or stenting and you can pick them out by doing microemboli
detection," he says. He is slated to present his findings today at the 6th
World Stroke Congress in Vienna, Austria.
Not everyone agrees with his conclusions, however.
Carotid Artery Stenosis: Study Details
Led by Spence, the team tested 199 patients treated before 2003 and 269
treated since 2003 for the presence of microemboli. Before 2003, medical
treatment was less aggressive.
The ultrasound procedure to find the microemboli, called transcranial
Doppler embolus detection, involves placing a helmet on the patient's head to
hold ultrasound probes in place, then using the ultrasound to monitor the
arteries inside the brain for the tiny clots or chunks.
"If you find two or more microemboli per hour, [the patient] should
probably have surgery or stenting," Spence says. All the patients in the
study had narrowing of the carotid artery, but had no symptoms.
Although 12.6% of the patients treated before 2003 had microemboli, just
3.7% of those treated since 2003 did, Spence found. The difference is
statistically significant, he says.
The research team then followed the patients for at least a year to see what
percentage had strokes or heart attacks. In those treated before 2003, "the
one-year stroke risk was 4%," Spence says. In those treated since 2003, it
"Heart attack risk went from 6.5% to zero percent," he says, with
the group treated since 2003 having no heart attacks.