Background: The effect of carotid endarterectomy (CEA) on cognitive functions is unclear. The aim of this study was to assess changes in cognitive functions following carotid endarterectomy (CEA) for high-degree stenosis.
Material and methods:
Patients without dementia or psychiatric disease including depression were included to the study after signing the Informed consent.
364 patients (181 symptomatic) were analysed from 8 centres during 28 months. In all patients The Addenbrooke's Cognitive Examination Revised (ACE-R) test, Mini Mental State (MMSE), Clock Drawing Test (CDT), Speech Fluency Test(SFT) were performed before CEA, 24 hours, 30 days and 1 year after. Demographic data, history of vascular disease, diabetes, smoking, medication, clinical status, vascular complications (stroke, TIA, new lesion on diffusion-weighted magnetic resonance imaging (DWI) and changes in cognitive tests were collected and analysed. The normality of data distribution was checked using the Shapiro–Wilk test. The Mann–Whitney U test was used for a statistical analysis.Logistic regression was used to identify factors affecting the changes in ACER.
Cognitive function testing 
 Mini Mental State Examination (MMSE) was used to assess orientation, registration (immediate memory), short-term memory and language functioning. This test is composed of 30 questions; 1point is given for every correct answer (result evaluation 0–30 points). 
Second was a clock-drawing test for a brief cognitive task testing executive functioning (memory, concentration, initiation, energy, mental clarity and indecision). Errors in clock-drawing are classified as omissions, perseverations, rotations, misplacements, distortions, substitutions and additions. The Shulman scoring system (0–5 points) was used for test result evaluation.
 Third, verbal fluency tests were used to test executive functioning and linguistic skills. Participants have to say as many words beginning with the letter ‘p’ as possible from a given category within 60s. This was scored from 0 to 7 points: 0–1 word, 0 points; 2–3 words, 1 point; 4–5 words, 2 points; 6–7 words, 3 points; 8–10 words, 4 points; 11–13 words, 5 points; 14–17 words, 6 points; and more than 17 words, 7 points. All cognitive tests were performed by a blinded investigator .
Results: 
13 from 145 patients (9%) had new lesion on DWI. 11 (3%) had a new stroke/TIA on day 30 and 3 more (0, 8%) after 1 year. Cognitive tests before CEA:  ACER 83,6±11,2, MMSE 27,3±3,1, CDT 4,3±1,2, SFT 9,8±3,3. Improvement in tests 24h/30d/1y were 3,0/4,2/2,5; 0,5/0,7/0,3; 0,03/0,13/0,11; 0,5/0,7/0,5  (p˂0,05 in all tests ). Symptomatic patients had better improvement in ACER after 1 month ( 5,5 vs 3,3 ; p = 0,01), after 1 year was no difference ( 2,5 vs 2,5;p=1,0). No influence of other factors were found.
Conclusion:
Cognitive functions improved after CEA with maximum on day 30 especially in symptomatic patients.
Supported by the Ministry of Health of the Czech Republic grant No. 17-31016A.

CHANGES IN COGNITIVE FUNCTIONS AFTER CAROTID ENDARTERECTOMY- ONE YEAR FOLOW UP