Should Carotid Patients Skip Surgery?

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, Canada.

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 was 0.8%.

"Heart attack risk went from 6.5% to zero percent," he says, with the group treated since 2003 having no heart attacks.