Study On The Effect Of Carotid Artery Stenting On Cognitive Impairment Of Patients With Carotid Artery Stenosis

Background：With the intensification of the social aging phenomenon, people paymore and more attention to elderly cognitive impairment, and the correlation of carotidartery stenosis with vascular cognitive impairment is also being widely concerned as well.Carotid artery stenosis not only plays an important role in the occurrence and developmentof the ischemic cerebrovascular disease, and also is considered to be an independent riskfactor for vascular cognitive impairment (VCI). Currently, the most effective treatmentmeasure for carotid artery stenosis is prevention, and targeted therapies mainly includemedication, surgery treatment and intravascular interventional treatment. The medicationmainly includes statins lipid regulating drug, antiplatelet and anticoagulant drugs; thesurgery treatment is the carotid endarterectomy (CEA); and the intravascular interventionaltreatment refers to carotid artery stenting (CAS). Due to advantages of little damage,relatively simple operation, pure local anesthesia, less perioperative complications andrapid postoperative recovery, the CAS is being widely applied in the treatment of carotidartery stenosis at present. On the one hand, the treatment of carotid artery stenosis canprevent the occurrence of ischemic stroke, on the other hand, it has some impact oncognitive function, but there is no unified conclusion of specific degree of impact at homeand abroad at present. In this study, the relationship between carotid stenosis and cognitiveimpairment was analyzed, and the postoperative following-up for CAS patients wereperformed to understand the changes in cognitive function during different CASpostoperative period, and to observe the specific impact of CAS on cognitive function aswell as exploring their mechanisms.Objective：The study aims to investigate the influence of carotid artery stenosis oncognitive function, so as to studyt the post-CAS (carotid artery stenting) cognitive changesfor the patients during various post-operation periods, as well as the possible mechanisms. Methods：The patients with acute cerebral infarction (anterior circulation) who wereadmitted in the Department of Neurology in our hospital between January2010andDecember2012, were enrolled and divided into four groups according to the severity ofcarotid stenosis, i.e. without obvious stenosis, mild stenosis (<30%), moderate stenosis(between30%and69%) and a treatment group (serious stenosis between70%and99%).The patients in the first three group only received medication; where as the patients in thetreatment group also underwent CAS besides being medicated. The cognitive functions ofthe patients were assessed by using Montreal Cognitive Assessment (MoCA), Mini-MentalState Examination (MMSE) and Stick Test. The changes in cognitive functions between thepre-operation period and the various post-operation periods were compared. In addition,SPECT/CT was employed to evaluate the post-operative improvement in local cerebralblood flow.Results：In pre-operation assessments, the patients in the treatment group had lowerMoCA total scores, lower MMSE scores and lower Stick Test scores when compared withthose in the control groups. Furthermore, their cognitive functions turned to be moreimpaired as the severity of carotid stenosis increased. The differences in the scores betweenthe patients in the serious stenosis group (treatment group) and those in the mild ormoderate stenosis groups were statistically significant. In the first week after CASprocedure, the performances of the patients in the treatment group at the various cognitivetests (MoCA, visual-spatial ability/executive function, delayed recall ability, concentration,MMSE, Stick test and ects.) all declined, with statistically significant differences whencompared with pre-operation scores. However, in the evaluations on3-and6-months postoperation, these patients showed much improved performances in all of these tests; and theimprovements were statistically significant. From the images obtained from the patients inthe treatment group by employing SPECT/CT superposition, the cerebral blood flows inthe targeted brain areas were compared with the average blood flow in the ipsilateralcerebellum both pre-and post-operatively; and the results showed that cerebral perfusionafter CAS was much improved, with statistically significant difference.Conclusions： Carotid artery stenosis was associated with vascular cognitiveimpairment, and the severity of impairment was positively correlated with the severity ofstenosis, i.e. the severity of stenosis increased as the severity of cognitive dysfunctionincreased. CAS was proved to be able to improve cognitive function, especially for the visual-spatial ability/executive function, delayed recall ability, concentration and so on.These improvements were probably attributed by the changes in cerebral perfusion. Inaddition, during the early post-operation stage, there may be temporary and reversiblecognitive degradation, which was probably associated with the perioperativehyperperfusion and microemboli detachment.