TUESDAY, Jan. 30, 2007 (HealthDay News) -- Doctors say older people who had a stent put into the main artery of their brain to prevent strokes got a real bonus: improved mental function.
The small study, which included 37 patients, found that 16 (43 percent) of them scored higher on a battery of 11 cognitive tests one year after the procedure, according to Dr. Rodney Raabe, chief of radiology at Sacred Heart Medical Center in Spokane, Wash.
Mental function remained the same in 20 other patients and declined in only one.
Half of the patients were considered symptomatic because they had suffered transient ischemic attacks (TIAs), also known as "mini-strokes." TIAs are caused by minor blockages in brain arteries, and their effects typically last only for hours. In this study, patients with TIAs had at least 70 percent blockage in one of the two carotid arteries that carry blood to the brain. The other patients had not suffered TIAs but their carotid arteries were at least 80 percent blocked.
Raabe stressed that, "our study is very small and needs to be verified in other trials. But this now tells us that people who previously were considered asymptomatic can have improved mental function because of improved blood flow."
If verified -- a process that would take years -- the finding could produce "giant savings in total care costs," Raabe said. In this small trial, "we had individuals who were going into nursing homes who were able to live at home," he said, and "individuals who could not work who went back on the job."
The findings were to be presented Monday at the International Symposium on Endovascular Therapy in Hollywood, Fla.
A stent is a tiny flexible tube implanted within a vessel to improve blood flow. All the individuals in the trial had stents implanted because a narrowing of the carotid artery had increased their risk of stroke.
The finding that many of these patients also experienced a mental boost came about because Raabe and his colleagues were looking for signs of damage.
"We did the study because those who undergo coronary bypass can have a cognitive deficit," he said. This loss of mental function is caused by microemboli, tiny blood clots that pass from the heart to the brain, he explained.
"The same kind of thing could be going on with coronary stenting," Raabe had surmised. "Our hypothesis was that we might see the same kind of neurological decline as with a coronary bypass. Now, a year later, we are reporting that mental function did not decline but mostly actually improved."
Raabe attributed the improved mental function simply to better blood flow to the brain.
Dr. Deepak Bhatt, associate director of the Cleveland Clinic's cardiovascular coordinating center, has done extensive work with carotid stenting. He believes that the observed benefit might also be due to the stent's preventing tiny bits of plaque in the artery from breaking off and damaging the brain.
Whatever the reason, the phenomenon seems to be real, Bhatt said. "Others have been skeptical," he said. "But I've heard it so often from patients, with corroboration from the family, that I finally believe there may be something going on."
He agreed that "this is a small study that needs to be duplicated. But with those caveats, I think their findings are quite believable."
There have been hints of such positive results in the past, Raabe said. One 1999 British paper that looked at 28 studies found that 16 of them reported improved mental function in people who got carotid stents, he said.
According to Raabe, what is needed now is a definitive trial that could lead to federal funding for carotid stenting -- not only to prevent strokes, but to improve brain function. "The [U.S.] National Institutes of Health needs to encourage this kind of study," he said.
More information
There's much more on carotid stenting at the Cleveland Clinic.
