"We now know definitively that we can reduce stroke risk by half with surgery to 'clean out' narrowed arteries leading to the brain - even in patients who have no symptoms," says neurologist James Toole, M.D. "We should offer this option to more patients, as well as begin screening seemingly healthy individuals for stroke risk."
Toole's comments are in response to a report in this week's The Lancet on the "Asymptomatic Carotid Surgery Trial," a study based in England of more than 3,000 patients. The results - that surgery to remove fatty deposits from narrowed vessels in the neck can significantly reduce stroke risk - were nearly identical to the findings of a study that Toole coordinated in the United States and Canada.
Both studies looked at the value of surgery, called carotid endarterectomy, in people who have no symptoms, but whose carotid arteries were narrowed by at least 60 percent, a condition called carotid artery stenosis. The surgery is typically offered only to patients who have symptoms of an impending stroke.
The idea that surgery can be beneficial for people without symptoms was not easy for physicians and researchers to believe when it was first reported in 1995, says Toole, a professor of neurology. "People were so astonished by this they thought the data were flawed. That led to the European study."
The recent study, called the Asymptomatic Carotid Surgery Trial and reported in The Lancet, involved 126 hospitals in 30 countries. The study randomized people with narrowed vessels to receive either surgery or daily aspirin and management of risk factors, such as drugs to lower cholesterol or high blood pressure. About 12 percent of those in the non-surgery group had strokes, half of them fatal or disabling. In the surgery group, 6 percent had strokes - a risk reduction of 50 percent.
From 1987 to 1993, Toole and colleagues conducted a similar study of 1,662 participants in the United States and Canada. That study, Endarterectomy for Asymptomatic Carotid Artery Stenosis, or ACAS, found that 11 percent of participants who were treated with medication had strokes. In the surgery group, the incidence was 5.1 percent - a 53 percent reduction.
More than 500,000 new strokes occur each year in the United States, and it has been estimated that carotid artery disease may be responsible for 20 percent to 30 percent of them.
"The research results, which confirm a benefit of surgery to prevent stroke in people who had no symptoms, despite having severely narrowed arteries, highlight two important issues for stroke prevention," says Charles Tegeler, M.D., professor of neurology at Wake Forest Baptist. "First, we need to screen more adults for narrowed carotid arteries. Second, patients with severe carotid narrowing should at least be considered for the surgery as a stroke-prevention treatment."
Toole recommends that men undergo a baseline screening of their carotid arteries between the ages of 50 and 60, depending on their overall health. The simple test, which was pioneered by Wake Forest, uses ultrasound technology to gauge artery health. Toole believes that both men and women with diabetes, hypertension or a family history of stroke - all which increase the risk of stroke - should be screened in their 40s.
The surgery can be performed under local or regional anesthesia. Wake Forest Baptist, which was the first in the country to perform the surgery while the patient was awake, today performs a majority of carotid endarterectomies this way. Across the country, however, many of the surgeries are still performed under general anesthesia.
John Wilson, M.D., a neurosurgeon at Wake Forest Baptist, said performing the surgery while the patient is awake allows even higher-risk patients to have the procedure with a low rate of complications.