All patients underwent endovascular therapy and received standard medical management after surgery, including dual antiplatelet therapy (aspirin and clopidogrel) for three months with aspirin or clopidogrel monotherapy thereafter and high-dose statin, and treatment of hypertension to guideline targets.

The changes in MMSE will also constitute the secondary research outcome. The full name of MMSE is mini-mental state examination, and the scale consists of 30 subjects, include the following seven aspects: time orientation, place orientation, immediate memory, attention and calculation, delay memory, language, visual space. One point is awarded for each question correctly answered during MMSE evaluation. If subject give the wrong answer or don't know answer he/she awarded 0 score, scope of scale score of 0 to 30 points. The higher the score, the better. In this study, the investigators suspect that scores would decrease after follow-up.

The changes in DST will constitute the secondary research outcome. Digital span test (DST) was commonly used to evaluate attention ability and instantaneous memory ability. There are two types of test: forward (0-14) and backward (0-13). In the forward test, the subjects were asked to retell the the digits immediately after hearing it until they could not be repeated correctly. In backward test, the subjects were asked to repeat a set of numbers in reverse order until they could not be repeated correctly. The length of the last set of Numbers correctly repeated by the subjects was the final score, forward and backward are counted separately. The higher the score, the better. In this study, the investigators suspect that scores would decrease after follow-up.

The changes in The Stroop color test will constitute the secondary research outcome measure. The Stroop color word test was developed by Stroop in 1935 and is used to evaluate the attention function of the subject. The subject is required to correctly read the target color on the stimulus card and record the completion time. The final completion time is the score of the participant. The shorter the time used, the better the performance of the subjects

The changes in CTT will constitute the secondary research outcome. The Color Trail Test (CTT) is divided into two parts, part A and part B. Part A requires the subject to connect 25 Numbers on the paper in sequence, and part B requires the subject to connect 25 Numbers of different colors alternately in sequence. The time it takes for the subject to complete all the Numbers is the subject's final score.In this study, the investigators suspect that scores would decrease after follow-up.

The clock drawing test is currently widely used in the evaluation of cognitive impairment, requiring a free hand drawing of a clock within 10 minutes with the pointer pointing towards 11:10, which can be well used to evaluate the visual spatial ability of participants. The commonly used scoring methods include the 3-point method, the 4-point method, and the 10-point method.

The changes in The Verbal Fluency Test (VFT) will constitute the secondary research outcome measure. The VFT can be used to evaluate the frontal lobe fluency of patients, mainly including semantic verbal fluency and phonemic verbal fluency.

The changes in HAMD will constitute the secondary research outcome. Hamilton Depression Scale (HAMD) compiled by Hamilton in 1960, is the most common clinical to assess Depression Scale. In this study, 17 versions were selected, and there were 17 questions. The subjects were assessed for their depression in the past week. Each question scored between 0 and 4 points.Higher scores indicate more depressive symptoms.

The changes in HAMA will constitute the secondary research outcome. Hamilton Anxiety Scale (HAMA) was compiled by Hamilton in 1959.It was one of the most commonly used scales in psychiatric clinic, including 14 items. It is often used in clinical diagnosis and degree classification of anxiety disorder. The subjects were assessed for their anxiety in the past week. Each question scored between 0 and 4 points. The higher the score, the more symptoms of anxiety.

The resting state magnetic resonance data were collected to compare the neuroimaging differences between the patients and healthy control groups.

The structural phase magnetic resonance data were collected to compare the neuroimaging differences between the patients and healthy control groups.

The three-dimensional pseudo continuous Arterial Spin Labeling (3D pCASL) data were collected to compare the differences in cerebral perfusion between the patients and healthy control groups.

Pulsatility index (PI) in the middle cerebral artery (MCA) is considered a measure of peripheral vascular resistance. The investigators want to explore the peripheral vascular resistance by MCA-PI.

The carotid intima-media thickness (IMT) is a widely used surrogate marker for atherosclerosis worldwide. The investigators want to explore the risk of recurrence of cerebrovascular events by IMT.

CRP is a plasma protein synthesized by the liver and is often used as a nonspecific biomarker of inflammation. Elevated CRP levels are associated with increased risk of cerebrovascular disease and dementia. The investigators intend to use CRP to explore the relationship between inflammatory response and cognitive impairment.

Oxidized low-density lipoprotein (oxLDL) is a biomarker that is a key factor for the occurrence and development of atherosclerosis and the formation of unstable plaque. Atherosclerosis has been associated with the onset, severity and progression of cognitive dysfunction. The investigators intend to further explore the relationship between LDL level and cognitive impairment.

microRNA (miRNA) is a type of non-coding single-stranded small RNA that plays a role in biological functions by regulating post-transcriptional gene expression. miRNA is involved in the regulation of synaptic plasticity and is related to learning and memory. The investigators intend to reserve serum samples for the study of miRNA and cognitive impairment.