A treatment designed to clear blocked carotid arteries and prevent stroke showed signs of improving brain function in a small study, U.S. researchers said Monday.
Doctors found nearly half of patients who were treated with a carotid stent to prevent a stroke showed statistically significant improvement in brain function, such as memory, judgment and reasoning.
Carotid stents are tiny wire-mesh tubes that are inserted via a small puncture in the groin and threaded through the blood vessels and into the carotid artery in the neck.
In a study of 37 patients implanted with the stents, 16 patients or 43 percent showed improved brain function a year after the stent was implanted.
Doctors noted cognitive improvements at three months and those gains continued when checked at six and 12-month intervals.
“Many patients have returned to a level of function they thought they had lost,” said lead researcher Dr. Rodney Raabe, chief of radiology at Sacred Heart Medical Center in Spokane, Washington, where the study was conducted.
James Benenati, an interventional radiologist at Baptist Cardiac and Vascular Institute in Miami, said the study confirms what he has seen in his own practice.
“Many of us anecdotally know this is true. Now it probably is important to do a larger study,” said Benenati, who was not affiliated with the research.
Highway to the brain
Located on either side of the neck, carotid arteries are the main blood conduits to the brain. Clogged carotid arteries account for nearly one third of all strokes.
Most patients with blocked carotid arteries undergo surgery to clear blockages, but recently approved carotid stents offer a less-invasive option for patients who face high risks if they undergo surgery.
Several medical device makers have U.S. regulatory approval for carotid stents, including Abbott Laboratories Inc., Boston Scientific Corp. and Johnson & Johnson, Ev3 Inc. and C.R. Bard Inc.
Doctors first inflate a tiny balloon in the artery, smashing fatty deposits against the artery wall. They then deploy a springy stent to provide structure to the diseased vessel and keep blood flowing to the brain.
A tiny net-like filter traps any fatty deposits dislodged during the procedure that could cause blood clots.
Currently the risk of stroke with either surgical or less-invasive stenting procedures is in the range of 4 to 10 percent, depending on the patient, Benenati said.
That risk would prohibit doctors from treating patients to improve brain function unless they were at risk of a stroke.
With better stents and more refined procedures, however, doctors ultimately could use the procedures to treat impaired brain function brought on by blocked arteries, Benenati said.
The stent study did not test whether there was a similar brain benefit for patients who undergo surgery to have their carotid arteries cleared.
Benenati said he assumes the same benefit would apply, but that also would need to be studied.