[Changes of brain function and cognitive function after carotid artery stenting]

Objective: To investigate the effect of carotid artery stenting(CAS) on cognitive function and brain function based on changes of a battery of neuropsychological tests and magnetic resonance imaging. Methods: Thirty-three patients were included with 17 in the stent-placement group and 16 in the control group (receiving medical treatment), among whom, the unilateral or bilateral severe internal carotid artery stenosis was confirmed by cerebral vascular angiography in the department of Interventional Radiology and Vascular Surgery of Zhongda Hospital Southeast University from June 2015 to September 2016.Neuropsychological tests and rest-state blood oxygenation level dependent fMRI were performed at the baseline and six months follow-up.The baseline characteristics and follow-up changes were compared in each group. Results: The overall cognitive function of the stent-placement group was statistically significantly improved (P<0.05) compared with control group, mainly in the executive function, memory, attention and other aspects.The value of amplitude of low-frequency fluctuation(ALFF) showed statistically significant increase (P<0.05, Alphasim correction) in left prefrontal cortex (t=5.861 3, P<0.05), the somatosensory association cortex in left superior parietal lobe(t=5.601 2, P<0.05) and bilateral motor cortical area in posterior frontal lobe (t=5.288 5, P<0.05). The ALFF showed statistically significant decrease (P<0.05, Alphasim correction) in left retrosplenial cingulate cortex(t=-5.590 4, P<0.05), left insular cortex (t=-6.340 8, P<0.05), right insular cortex (t=-8.129 9, P<0.05) and left dorsal anterior cingulate cortex (t=-5.584 8, P<0.05). There was no statistically significant difference (P>0.05, Alphasim correction)between baseline and follow-up results in control group.Besides, the ALFF changes of the left insular cortex (r=-0.591, P=0.033) and bilateral motor cortical area (r=-0.659, P=0.014) were negatively correlated with auditory verb learning test (AVLT) score changes.The ALFF change of bilateral motor cortical area was negatively correlated with the AVLT-delay score change (r=-0.588, P=0.034). And the ALFF change on right insular cortex and the frontal assessment battery (FAB) score change was positively correlated (r=0.638, P=0.025). Conclusions: The overall cognitive function of patients with carotid artery stenosis significantly improve after CAS compared with medical treatment.The change of ALFF value in related brain area is also statistically significant.ALFF Change most in area of Default Mode Network may suggest a mechanism of postoperative neurological recovery in patients with carotid artery stenosis.