Both clinically symptomatic and asymptomatic patients have significant improvement in brain function after carotid artery stenting, according to a presentation at the annual meeting of the Society of Interventional Radiology.

The current study involved the most comprehensive measurement of pre- and post-neurocognitive effects in any study to date involving carotid stenting. The trial results corroborate results from two previous small studies in the US and Germany. As documented in the study, pre-stenting deficits in asymptomatic patients primarily involved executive functions.

“We know from previous studies that carotid stenting can prevent a stroke in those at high risk, but what we didn’t know is that the treatment makes people’s brains function better. Their memory improved, some say they see colors brighter, and they can think better,” said study author Rodney Raabe, MD, interventional radiologist.

Currently, clinically asymptomatic patients are generally treated if their carotid artery is more than 80 percent stenosed because that level of blood flow impairment clearly raises risk for stroke. Symptomatic patients, who have had a stroke or a transient ischemic attack, are treated to prevent future stroke.

In the current study, asymptomatic patients improved the most in neurocognitive function, most likely because they had not experienced previous brain injury from strokes or transient ischemic attacks. Though all those studied showed improvement, younger patients also had better outcomes. They have more neurocognitive reserve and had the biggest gains in neurocognitive function. The improvement was due to the increase in blood flow to the brain as shown on MRI after the procedure.

The study involved very sophisticated neurocognitive measures including intelligence quotient, handling of spatial relationships, memory and other executive functions. Patients were tested for memory and executive function five times before and an additional four times after the procedure.

The tests include the ability to respond to a command, integrate the command, and provide an answer in return. Functions were also tested, such as word memory, number memory, and putting things in order. These functions improved, even in patients with a lower degree of stenosis, and the improvement was statistically significant.

The presentation involved interim results and analysis in 26 patients at six months in this ongoing study. The purpose of this study was to test the hypothesis that carotid stenting with filter protection can prevent neurocognitive deficit due to little pieces of plaque breaking off during the procedure and causing trauma if they reach the brain. The study used the AcculinkTM stent and the AccunetTM embolic protection filter, which captures microemboli that might come loose during the procedure, preventing it from traveling to the brain in the bloodstream.

“We know when patients have a coronary bypass operation with aortic clamping, that there is a memory and cognitive decline from microemboli that reach the brain and cause permanent damage to brain function. We thought microemboli that might break loose during stenting could cause the same effect and wanted to see if filter protection would prevent this,” said Raabe.

The study shows that using the embolic protection filter did save patients from neurocognitive decline and the author concludes that an embolic protection device is beneficial and should be used during carotid stenting procedures. The filter has a membrane so small that only very small particles like blood can get through. Any plaque that might break off during the procedure is captured in this filter. It closes like an umbrella and is withdrawn in the catheter after the stent is deployed.