Microemboli detection in patients with carotid artery stenting--a potential marker for future cognitive impairment?

To monitor the long-term cognitive function evolution of patients undergoing carotid artery stenting (CAS), using detection of embolic signals (ES) as a potential marker of cognitive decline.

This is an ongoing prospective nonrandomized single-center study of patients undergoing carotid artery angioplasty and stenting using standard techniques. Neurologic status is evaluated by history, physical examination and the National Institutes of Health Stroke Scale. A complete Doppler-ultrasound investigation of the brain-supplying arteries has been performed in every patient. A 45minute cognitive battery designed to assess motor speed/coordination and executive function, psychomotor speed, language (naming), working memory/concentration, verbal fluency, and learning/memory is performed by a certified neuropsychologist in the first week after CAS and repeated a year after the procedure. Each patient undergoes bilateral ultrasonographic-Doppler monitoring of the middle cerebral artery (MCA) for microemboli detection. The patients are monitored during the first week after CAS and again a year after stenting.

32 patients were included. The mean baseline Mini-Mental State Examination (MMSE) score was 28.7 points. During the first ultrasonographic monitoring 28 patients (87.5%) had at least three times more ES detected on the stented side (a mean of 24ES/30minutes was detected in the stented side compared to a mean of 4ES/30min in the non-stented side). At the one-year follow-up 68% of the patients who have undergone CAS maintain a high number of ES detected in the territory of the stented carotid artery, finding that is well correlated with the cognitive decline in those patients, as assessed by the MMSE score.

ES detection is a useful tool for predicting cognitive decline that can be used to monitor CAS patients and adjust preventive measures in order to avoid progression of vascular cognitive impairment. It is important that further studies comparing carotid endarterectomy and CAS monitor long-term cognitive function outcome.