Brain stents pose risks

Threading a catheter up into the brain and inserting a device that widens a dangerously narrowed artery might do more harm than good in some patients at risk of stroke. An aggressive course of medications alone appears to be safer, researchers report online September 7 in the New England Journal of Medicine.

Mesh cylinders called stents have offered cardiologists an inside-out approach to opening clogged coronary arteries that is less invasive than surgery. Now researchers are using a new generation of tiny stents to tackle similarly narrowed vessels in the brain. Federal regulators approved a brain stent in 2005, and past studies have supported stents’ effectiveness against stroke (SN: 2/17/2007, p. 99).

Researchers used the approved stent in the new trial. They enrolled hundreds of patients at 50 hospitals who had just survived a stroke or had a transient ischemic attack, a kind of stroke that clears up within a day, says study coauthor Marc Chimowitz, a neurologist at the Medical University of South Carolina. The average age of the patients was about 60.

Brain scans of these patients pinpointed an artery with buildup that obstructed at least 70 percent of blood flow. People with such bottlenecks are at high risk of having a stroke, because a blood clot may form at the narrowed spot and block blood flow, or a loose clot might get lodged at the pinch point. All patients received clot-busting medicines — aspirin and clopidogrel (Plavix) — and were given drugs to lower cholesterol and control blood pressure.

In addition to the aggressive drug regimen, half the people were randomly assigned to get a stent to widen the narrowed brain artery. Although study coordinators planned to include about 760 patients in the study, recruitment was stopped after the researchers had enrolled only 451 patients.

Nearly 15 percent of patients getting a stent died or experienced a stroke within 30 days of joining the study. All those strokes occurred within a week of stent placement — often on the first day. Of the patients getting medication only, less than 6 percent of them had died or had a stroke within the first 30 days.

After one year, about 20 percent of the stent group and 12 percent of the drugs-only group had died or had a stroke. The stented vessels hemorrhaged in some cases.

Translating the stent success seen in coronary arteries to fragile brain vessels has been tricky. “It’s very attractive to think that if you can make the vessel picture look better, the patient will do better,” says Walter Koroshetz, a neurologist and deputy director of the National Institute of Neurological Disorders and Stroke, in Bethesda, Md. “But it really has to be proven.”

Several companies make stents, and ongoing studies may clarify whether they can prevent strokes in some people. “I don’t think the [stent] intervention approach is dead,” Koroshetz says, but he believes brain surgeons will need better stents that don’t damage the vessels upon insertion.