Marilynn Marchione, AP

People at risk of a stroke because of narrowed neck arteries can be safely treated with a less drastic option than the surgery done now, the largest study ever done on these treatments concludes. If Medicare agrees to cover it, hundreds of thousands of Americans a year might be able to have an artery-opening procedure and a stent instead of surgery to remove built-up plaque, doctors say.

Stents have long been used to fix heart arteries but are approved for use in the neck only for people too sick for surgery. The new study, in people with less severe disease, suggests stents may find much wider use.

However, the treatments have different complications, and not all doctors are convinced stents are as safe. Three previous studies found they were not, including one published online by the British journal The Lancet.

The reason: Even though stents prevent strokes in the long run, the procedure itself can trigger a stroke if a bit of plaque travels to the brain. The new study revealed a tradeoff: Strokes were a more frequent complication with stents, while heart attacks were more common after surgery.

Doctors say which option a patient chooses may depend on their general health, what risks they are willing to accept and how badly they want to avoid surgery. Surveys show that people worry more about stroke than a heart attack, said Dr. Lee Schwamm, a top neurologist at Massachusetts General Hospital.

About 795,000 Americans each year suffer a stroke. Many are caused by a clot that forms in a narrowed neck artery and travels to the brain. Doctors can check for narrowed arteries by using a stethoscope to listen for abnormal sounds in neck arteries, and a painless ultrasound test can show blockages.

The top treatment has been to cut the artery open and remove the plaque surgically. To place the stents, doctors will put a tube in a blood vessel in the groin and push it to the narrowed artery. A parachute-like filter is placed to trap bits of plaque that dislodge and keep them from traveling to the brain. A balloon is inflated to flatten the clog, the stent is placed to hold the artery open, and the filter is removed. The patient is awake but sedated.

The study involved 2,502 patients in the United States and Canada. Half had recent symptoms such as a ministroke. The rest had no symptoms but significantly narrowed neck arteries. They were given either surgery or a stent made by Abbott Vascular, which helped sponsor the trial.

A month later, about 4 percent of the stent group had suffered strokes versus 2 percent of those who had surgery. About 2 percent of the surgery group had heart attacks compared to 1 percent of those given stents. There were nine deaths in the stent group versus four in the surgery group, but the difference in a study this size was so small that it could have occurred by chance alone. Age was also a factor as those under 70 were slightly better off with a stent, while older patients fared better with surgery.

The study did not include a group of patients treated only with medicines to control stroke risk factors, such as high blood pressure and cholesterol. Without such a comparison group, it's impossible to know just how many strokes either treatment prevented.

About 30,000 neck stents were used last year compared to 100,000 surgeries. Medicare pays $7,500 to $11,000 for surgery; stents cost around $12,000 because of the price of the devices, which range from $3,500 to nearly $5,000. “There may be advantages and disadvantages in different types of cases” for stents or surgery, said Dr. Barry Katzen, medical director at Baptist Cardiac & Vascular Institute in Miami, who had patients in the study. “Like many areas of medicine, patients will have a choice.”