The Food and Drug Administration is restricting use of a medical device made by Stryker that props open clogged brain arteries, after reviewing studies suggesting the implant can actually increase stroke and death in some patients.

The FDA approved the Wingspan stent in 2005 for patients with plaque-filled arteries in the brain, which can lead to stroke. The agency now says the device should be used only for a small segment of patients who have experienced multiple strokes but have not had any stroke symptoms in the last seven days.

The agency’s announcement comes after Public Citizen, a public safety advocacy group, called on the agency to take the device off the market entirely. A petition filed by the group last year pointed to a recent study that found a 2.5-fold increase in stroke or death among patients with the Wingspan stent system, compared with patients taking blood-thinning medication alone.

In its announcement Wednesday, the FDA acknowledged those risks but said the device may still be beneficial to patients who have not responded to other therapies.

“After careful consideration of available safety information, the FDA believes this device should remain available for this specific subgroup of patients who have exhausted other options,” said Dr. Jeffrey Shuren, director of the FDA’s center for devices.

Wingspan consists of a small, mesh metal tube that is braced into place via inflatable tube, promoting blood flow through the arteries to the brain. The stent was approved under a special program that grants speedy approval to devices for rare diseases and conditions that affect less than 4,000 people in the U.S. each year. The device was first developed by Boston Scientific Corp. and later sold to Kalamazoo, Mich.-based Stryker Corporation.

Shares of Stryker fell 7 cents to $52.93 Wednesday afternoon.