Objective: Neurocognitive dysfunction still remains a frequent problem after heart surgery, complicating early recovery and strongly affecting postoperative quality of life. The aim of our study was to determine incidence of cognitive dysfunction after coronary artery bypass grafting for patients of low risk group and to find operative and postoperative factors associated with early cognitive impairment.
Material and methods: Using exclusion criteria, which are known as risk factors for postoperative neurological complications we selected a group of 30 coronary artery bypass grafting patients. The day before surgery and 7 to 8 days after operation we evaluated cognitive function of each patient using MMSE and standardized test battery of five neuropsychological tests. The incidence of cognitive decline was evaluated using composite z scores and 1 SD criteria. Preoperative ultrasound screening of asymptomatic carotid artery was performed for each patient.
Results: Early postoperative cognitive dysfunction was present in 13 (46.3%) of patients. Patients with cognitive decline more often had asymptomic, hemodynamicly significant carotid artery stenosis. Duration of operation and coronary artery bypass time was longer in cognitive dysfunction group. As well there were more grafts performed to this group of patients. We noticed a relationship between lower temperature during coronary artery bypass and cognitive impairment.
Conclusions: Incidence of cognitive dysfunction for patients of low risk group was 46.3%. Cognitive decline was associated with prolonged coronary artery bypass, operation time and number of grafts.