New stent method slips into stroke prevention

Stents, long famous for their success in propping open clogged arteries near the heart, are now being used in neck arteries in an effort to reduce strokes.

The technique is so promising that some experts now fear doctors may adopt the procedure -- and patients may clamor for it -- before research truly supports it.

With carotid stenting, doctors insert a mesh device into a clogged artery in the neck to keep blood flowing to the brain. The stents can be placed without general anesthesia.

“The procedure is less invasive and recovery is faster than with endarterectomy,” the traditional, surgical approach to fixing narrowed arteries, said Dr. Marc Mayberg, executive director of the Seattle Neuroscience Institute. But he worries carotid stenting “may be over-applied in patients who actually don’t need it ... or who would do well on medications alone.”

So far, he said, “there is little scientific data yet to show that stents are an effective way to prevent strokes, while there is such data for endarterectomy,” in which arteries are cut open and fatty debris is scraped out. Every year, roughly 150,000 Americans undergo this procedure.

Already, however, carotid stenting has a number of fans. It’s clearly “the coming thing,” said Dr. Barry T. Katzen, medical director of Miami’s Baptist Cardiac and Vascular Institute.

“We now have equipment that is much smaller, much more elegant,” making the procedure easier and safer, said Dr. Piotr Sobieszczyk, cardiologist at Brigham and Women’s Hospital.

Although carotid stenting has been around since the early 1990s, it is taking off now because engineers have added filters to catch debris that can be knocked off during stent insertion.

Such debris could otherwise travel to the brain and cause strokes -- the very thing that doctors are trying to prevent. At the end of the procedure, this filter, debris inside, is withdrawn.

Stenting got another boost last year when Medicare agreed to pay for it in certain patients.

Despite its promise, though, stenting will probably not be the first choice for many people.

Though some strokes occur because of bleeding in or near the brain, most are ischemic strokes that occur when blood to the brain is blocked by a clot or fatty plaque that has broken off from artery walls. Carotid stents are designed to prevent the small percentage of ischemic strokes caused by plaque.

Although there are fewer data on stenting than on surgery to prevent strokes, a major study published in 2004 showed that carotid stents were as effective at reducing strokes as endarterectomy and were linked to fewer heart attacks during the procedure. The risks of endarterectomy include infection and injury to nerves in the neck; stenting can disturb heart rhythms by dilating the carotid artery, which in turn affects the vagus nerve.

On the plus side, there is preliminary evidence that carotid stenting may improve cognitive function, said Dr. Rod Raabe, an interventional radiologist at the Sacred Heart Medical Center in Spokane, Wash.

But should stenting be used for people at moderate risk of stroke who have no overt symptoms such as TIAs, or transient ischemic attacks, also known as mini-strokes? That issue is being addressed in the CREST study, funded by the National Institutes of Health, which is still open to new patients.

Until that study is finished, the prudent course, if you are at risk for stroke -- because of high blood pressure, smoking, clogged carotid arteries or other factors -- is to talk with your doctor and try medications first.

If these don’t work, carefully weigh the more invasive options. Ask how much training the doctor has had in the procedures. And don’t be afraid to get a second opinion.