Patients who have blocked carotid arteries, the major source of blood flow to the brain, even if there are no symptoms, experience significant improvements in intellectual functioning after they undergo surgery to correct this problem, investigators reported Friday at the Society of Interventional Radiology’s annual meeting in Toronto.

In fact, younger patients and those who have not had a stroke appear to experience the most benefit from the procedure. Carotid stenting involves placement a “stent,” a device use to prop open the blocked vessels. Strokes can occur when plaques that have formed in the carotid arteries, which lie on each side of the neck, break off or otherwise obstruct blood flow to the brain.

“What we found was earth-shaking,” presenter Dr. Rodney D. Raabe, of Sacred Heart Medical in Spokane, Washington, told Reuters Health. The findings will change the way we think about carotid artery disease, how it is treated and how patients are classified.

He pointed out that his group’s initial goal was to show that using a protective filter during carotid artery stenting would prevent decline of mental function after the procedure.

The study included 40 patients, half of whom were considered to be symptomatic - meaning that they had carotid artery blockage and a previous stroke or neurologic event - and half were asymptomatic, but also had artery blockage.

“So far, we’ve conducted 6-month evaluations on 30 patients with an extensive battery of neurocognitive tests,” Raabe explained. “Remarkably, they all showed significant cognitive improvement, especially in executive function, their ability to think abstractly, make judgments and reason.”

In fact, he added, “some patients whose functioning was so poor that they were being considered for nursing home placement, are now doing quite well living independently at home. This study shows that people, even before they have a stroke, are probably not functioning as well as they could be.”

Currently, the only reason carotid artery blockages are treated in the US is to prevention stroke. However, if these results are repeated in larger studies, it will show that patients who have more than an 80 percent blockage are not asymptomatic, “they do have symptoms, but it takes complicated testing to measure it,” the researcher said.

He believes patients with early dementia may actually be experiencing the results of blocked carotid arteries and that their condition can be reversed. “They should be looked at to see if they have an asymptomatic blockage.

In the future, we probably won’t wait so long to treat patients with narrowing of the carotid artery because they’re showing functional neurocognitive impairment, and they’ll think better once we treat them.”