Correlation between Higher Brain Dysfunction and Cerebral Blood Flow after Carotid Artery Stenting

OBJECTIVE: This study investigated the changes in higher brain function and cerebral blood flow (CBF) after carotid artery stenting (CAS), the relationship with CBF, and the impact of high intensities in diffusion-weighted imaging (DWI) after CAS. METHODS: We performed CAS between September 2017 and September 2019 in our department in 88 patients. Patients who did not undergo higher brain function tests according to our protocol or those who did not consent to participate in our study were excluded. This study targeted the 26 patients who were able to undergo the tests, including the Kana Pick-out Test (KPOT) II, three times: before, 1 week after, and 1–3 months after CAS. We investigated the chronological changes in higher brain function and their relationship with high intensity on DWI. RESULTS: The results of Symbol Digit Modalities Tests (SDMT) and KPOT I and II improved significantly. There was a significant correlation between the improvement of higher brain function and CBF in patients with stenosis exceeding 60%, a score of the Mini-Mental State Examination (MMSE) of 26 or less, and without other cause of higher brain dysfunction, including known dementia. High-intensity spots on DWI after CAS had no significant impact on higher brain function. CONCLUSION: Higher brain function associated with attention and working memory improved significantly after CAS. There was a correlation between the improvement of higher brain function and CBF in patients with severe stenosis, mild cognitive impairment, and no known dementia. The prevention of subsequent ischemic attack and higher brain function should both be taken into account when performing CAS.