Evaluation of Cognitive and Biochemical Brain Status in Patients after Carotid Endarterectomy

INTRODUCTION: In the large studies such as NASCET, ESCT, VACS, ACAS and ACST-1, the role of alteration of the cognitive functions of a patient in the early and long-term postoperative periods have not been determined. AIM: To evaluate the biochemical parameters of cerebral functions, the cognitive status of patients, and their interrelation after carotid endarterectomy. MATERIALS AND METHODS: The study involved 60 patients divided into two groups. The mean age was 67.3 ± 7.9 years, there were 49 (81%) men and 19 (19%) women. Group A included ‘symptomatic’ patients (n = 30) who underwent carotid endarterectomy and had a history of an acute cerebrovascular event. Group B included ‘asymptomatic’ patients (n = 30) who underwent carotid endarterectomy but had no history of cerebrovascular events. As part of the study, the following data were evaluated within a 6-month period: cognitive status (on MMSE, FAB, MoCA-test, NIHSS scales), biochemical parameters (S100b protein, neuron specific enolase (NSE), brain derived neurotrophic growth factor (BDNF)) and the ultrasound data of the carotid arteries. RESULTS: Patients of group A showed improvement of the cognitive status by the 6th month on MMSE scale (p = 0.001) and in MoCA-test (p = 0.09) relative to the initial parameters; on FAB scale relative to the data after 1 month (p = 0.01); a decline of the level of neurological deficit on NIHSS scale (p = 0.01). In group A, an inverse correlation was found between the results on MMSE scale and resistance index (r = -0.675; p = 0.005), and a direct correlation between the results on FAB scale and the end diastolic pressure in the internal carotid artery (r = +0.912; p = 0.005) according to the ultrasound data. The data obtained in group B, reflected improvement of the cognitive status by the 6th month only by 2 points on MoCA test (p = 0. 03) relative to the initial data. Besides, in 6 months after the surgery, there was a 2-fold increase in S100b marker (p = 0.01) and NSE protein (p = 0.02) and a 1.5-fold increase in BDNF protein as compared to the initial values (p = 0.005). CONCLUSIONS: Carotid endarterectomy leads to improvement of the cognitive status evaluated on MMSE, FAB, MoCA, NIHSS scales in the long-term postoperative period in symptomatic patients. The extent of improvement of neuropsychological status depends on the level of the end diastolic pressure and resistance index in the internal carotid artery on the operated side.