Identification of the Profile of Cognitive Deficit in Cardiac Surgery Patients Using the Optimal Clustering Method

An original clustering method based on discrete optimizationof multidimensional objects according to many heterogeneous parameters:age, severity of carotid artery stenosis (CA), personal and cognitive characteristicswas used to identify pre- and postoperative specificity of the profileof cognitive functions. The study involved 163 cardiac surgery patients.Determination of CA stenosis was carried out in the preoperativeperiod using color duplex scanning and further classification ofthe lesion. Psychometric assessment of personal and situationalanxiety, as well as psychomotor and executive functions, attention,short-term memory was performed 3–5 days before and 7–10 days aftercoronary artery bypass surgery (CABG). As a result of clusteringarrays of 17 normalized indicators and subsequent analysis of threegroups formed in this way, different dynamics of restoration ofthe profile of cognitive functions after CABG were discovered. Oneof the groups was designated as a group of cognitive reserves accordingto its best indicators of information selection and memory bothin the preoperative and postoperative periods. Another selectedgroup was characterized by a postoperative increase in the speed ofinformation selection, but low memory scores. The third selectedgroup demonstrated close relationships between indicators of attention,memory and the efficiency of a complex visual-motor reaction withage and the degree of stenosis of the CA, regardless of the pre-or postoperative testing period, which may indicate persistent disorganizationof cognitive functions in such patients, requiring special attentionwhen choosing neuro- and cardiac rehabilitation programs for them.The developed clustering method makes it possible to group patientsaccording to a variety of heterogeneous parameters to identify thedynamics of their changes during the course of treatment.