Carotid surgery stands test of time

Thousands of people have avoided strokes by opting for preemptive surgery that removes a coating of hard plaque from the inside of a vital neck artery. A new study finds that this surgery has long-term benefits and seems to protect against stroke even if done years after a patient first shows signs of such a blockage.

Symptoms of a blockage in the Y-shape carotid artery, which supplies the head with blood, include transient episodes of tingling or numbness in arms or legs, slurred speech, and a blackout of vision in one eye. Researchers see these as warning signs of stroke because the artery can close off or plaque can rupture and form clots that lodge in the brain. Symptoms of carotid blockages often go away within minutes or hours but the stroke risk remains.

Surgeons began clearing away such blockages, a procedure called carotid endarterectomy, in 1954. But organized trials to gauge its effectiveness didn’t begin until the 1970s. The surgery remains controversial because the operation carries a risk of causing the very kind of stroke it seeks to avert (SN: 4/11/98, p. 229).

In the September Stroke, researchers report on patients diagnosed between 1987 and 1991 with symptoms and with one branch of their carotid artery largely blocked. Some patients then received medication only, while others got medication and surgery.

The scientists watched for strokes originating on the side of the brain fed by the partially blocked artery. About 28 percent of patients getting medication but no surgery had such a stroke in the first 3 years of the study. Only 9 percent of people getting surgery had a stroke in that time, says study coauthor Henry J. M. Barnett, a neurologist at the University of Western Ontario in London, Ontario.

In 1991, when the benefits of surgery became apparent, the researchers offered all participants the option of surgery. By 1997, intriguing patterns were emerging. People who received the surgery promptly after the onset of symptoms had roughly one-fifth fewer subsequent strokes than those treated without surgery. Those who received delayed surgery benefited somewhat less.

“To ensure the greatest benefit, operating sooner is better than later,” says study coauthor Michael Eliasziw, a biostatistician at Western Ontario.

Some participants who declined surgery avoided stroke—probably because their blockage cleared, Barnett says. Or, their blood may have taken a detour to supply the brain via other arteries.

The data bolster earlier findings that indicated the procedure has long-term value. It also supports the notion that people who have transient symptoms and considerable blockage should get the surgery, says neurologist John R. Marler of the National Institute for Neurological Disorders and Stroke in Bethesda, Md.

The results come at a time when researchers are looking into other ways of fixing blocked carotids. One proposed technology would combine balloon angioplasty with insertion of a stent, a cylindrical mesh that props open an artery. Any of these new methods, however, will have to meet or exceed the benefits of endarterectomy, Marler says.