Impact of preoperative mild cognitive impairment on cerebrovascular events and cognitive status in patients undergoing coronary artery bypass grafting: data from 5-year follow-up

Abstract

Aim. To assess the incidence of cerebrovascular events and cognitive status in the long-term period after coronary artery bypass grafting (CABG) in patients with and without preoperative mild cognitive impairment (MCI).Material and methods. This prospective study involved 115 patients aged 45 to 69 years, who were admitted to the hospital for elective on-pump CABG. All patients underwent clinical, laboratory, ultrasound, neuroimaging and neuropsychological examination 3-5 days before and 5-7 years after CABG. Cognitive functioning was assessed using screening neuropsychological scales and neuropsychological testing with an assessment of neurodynamics, attention and short-term memory. Pre-CABG MCI was diagnosed based on the criteria by R. Petersen et al. Therefore, the patients were divided into two groups: with (n=51) and without MCI (n=64).Results. It was found that strokes and dementia during the long-term postoperative period of CABG were observed only in the group of patients with preoperative MCI (7,84%). Five-seven years after CABG, a decrease in cognitive status according to neuropsychological scales was found in all patients (p≤0,05). A decrease in neurodynamics, attention and short-term memory compared to the preoperative level was found in 47,92% of patients with preoperative MCI, without MCI — in 40,63%. Neurodynamic disorders occurred equally frequently in both groups (63,8% and 57,8% of patients, respectively). Memory impairments were more often observed in patients with MCI (55,3%) compared to those without MCI (34,4%) (OR=2,36, 95% CI, 1,09-5,12, p=0,03). According to brain multislice computed tomography in the group with preoperative MCI, the number of patients with cysts and leukoaraiosis 5-7 years after CABG was higher than in those without MCI (p≤0,05).Conclusion. In the long-term (5-7 years) postoperative period of CABG, more than 40% of patients demonstrate a decrease in cognitive status, regardless of preoperative data. At the same time, preoperative MCI is associated with adverse cerebrovascular events and dementia, accompanied by morphological brain abnormalities. Due to the revealed facts, it is necessary to optimize approaches to drug treatment and secondary prevention of cognitive decline after cardiac surgery.

Keywords

• cognitive impairment
• coronary artery bypass grafting
• long-term postoperative period