Stenting of the carotid artery significantly improves cognitive speed and may improve memory function in some patients, according to research presented today at the annual meeting of the Radiological Society of North America (RSNA) in Chicago.
"To my knowledge, this is the first study combining neuropsychological testing and perfusion imaging that screens for silent ischemic stroke events that can occur during stenting," said Iris Q. Grunwald, MD, consultant at Saarland University Clinic in Homburg, Germany.
Each year, approximately 600,000 Americans experience a stroke, one-quarter of which are caused by carotid arterial occlusive disease, or a narrowing of the carotid arteries. Until recently, surgery was the standard treatment for this disease, but carotid artery stenting has emerged as an accepted minimally invasive alternative to restore blood flow to the brain.
To perform the procedure, an interventional radiologist inserts a long catheter into a tiny incision in the common femoral artery in the leg. Using an image-guidance system such as CT and a guide wire, the radiologist positions the sheath at the site of the narrowing, or stenosis, in the carotid artery, expands the artery with a balloon and inserts a stent to hold the artery open.
While stenting is known to be an effective treatment for stroke prevention, little is known on the treatment's effects on cognitive function.
Grunwald and colleagues performed carotid artery stenting on 26 patients. All were given neuropsychological tests at least 24 hours before and three months after the stenting procedure. These tests included tests for cognitive speed (how quickly the brain processes information) and memory function. Patients were also tested for dementia and depression. The researchers examined the patients with diffusion- and perfusion-weighted MRI before and after stenting.
The results showed that cognitive speed increased significantly after stenting, regardless of the patient's age or the severity of the stenosis. In addition, the researchers found a correlation between the degree of vessel stenosis and perfusion deficit, or decreased blood flow, in the brain area on the side of the stenosis. Increasing the blood flow by stenting resulted in an increase in memory function in patients with perfusion deficit.