Incidence of postoperative cognitive dysfunction after simultaneous carotid surgery and coronary artery bypass grafting in patients with asymptomatic cerebral atherosclerosis

Abstract

To evaluate the incidence of early postoperative cognitive dysfunction (POCD) after simultaneous carotid surgery and coronary artery bypass grafting (CABG) in patients with asymptomatic cerebral atherosclerosis. Fifty-three patients with polyvascular disease and asymptomatic cerebral atherosclerosis undergoing simultaneous unilateral carotid endarterectomy (CEE) and CABG were recruited in the study. Core cognitive functions were assessed with the Mini Mental State Examination (MMSE) and Frontal Assessment Battery (FAB) at days 2-3 before the indexed surgery and at days 7-10 after it. All the patients were assigned to two groups based on the baseline MMSE score: one group with mild cognitive impairment (MCI) and another one without MCI. Neurodynamic measurements were performed using the Status-PF hardware-software complex (certificate #2001610233 of the Russian Agency for Patents and Trademarks), followed by the calculation of the integral indicator of the main cognitive domains according to the corresponding algorithms. Attention, memory and neurodynamics were evaluated in all participants. POCD was diagnosed with a decrease from the initial indicators of memory, attention and neurodynamics by 20% in 20% of the tests. Patients had complications in the early postoperative period, regardless of the presence of MCI. A decline among the core cognitive functions was observed in both groups of patients at days 7-10 after the surgery. Patients demonstrated an increase in the reaction time while performing neurodynamic test battery compared with the baseline values. Alterations in memory and attention were not significant. Significant changes in the integral indicator of cognitive status were determined in both groups of patients. It increased by 14% in patients without MCI (0.34±0.2 in the preoperative period vs. 0.39±0.3 in the postoperative period, p=0.04), and by 36% in patients with MCI (0.25±0.19 vs. 0.39±0.3, p=0.003). Regardless of the presence or absence of MCI, all patients had low cognitive status or even that below the average in the perioperative period. Despite the increase in the average values of cognitive status indicators in the postoperative period, 56% of patients (n=14) without MCI and 71% of patients with MCI (n=20) had early POCD. Patients with polyvascular disease, regardless of the presence of MCI, had low cognitive status or even that below the average, probably contributing to the elimination of the expected positive effects of CEE. The absence of MCI at baseline does not guarantee the preservation of cognitive status after surgery. Patients with polyvascular disease after myocardial and cerebral revascularization remain at high risk of exacerbating cognitive impairment, and, therefore, require an individual approach and a reasonable choice of the optimal surgical strategy.