Objectives. To assess changes in cognitive functions in patients with ischemic heart disease before and after elective aortocoronary bypass (ACB). Materials and methods. A total of 192 patients took part in the study and were divided into three groups. Group 1 included 88 patients who underwent ACB using the standard method (SM) with extracorporeal circulation; group 2 consisted of 61 patients who received a differential methodology approach (DM) to selection of the method for ACB; the control group included 43 patients. Neurological testing was performed using the Mini Mental State Examination, the Frontal Assessment Battery, the clock drawing test, Schulte tables, the verbal associations test, and the Wechsler Adult Intelligence Scale. Results and conclusions. Post-operative cognitive dysfunction was found to occur 3.2 times more frequently using SM ACB, while patients in the DM group showed a tendency to improved cognitive functions after surgery.