Lower Preoperative Verbal Memory Performance Is Associated with Delirium after Coronary Artery Bypass Graft Surgery: A Prospective Cohort Study

OBJECTIVE: Cognitive impairment constitutes one of the major risk factors of delirium after coronary artery bypass graft (CABG) surgery; however, it is unclear whether only patients with global cognitive decline are at increased risk for delirium or if individuals with preserved global cognitive functions but impairments in specific cognitive domains are also more vulnerable to developing delirium. Thus, this study aimed to analyze the neurocognitive status of patients scheduled for CABG surgery with the use of an advanced computerized cognitive battery (CNS Vital Signs) and to investigate possible associations between impaired performance in selective cognitive areas and the risk of postoperative delirium development. METHODS: The study enrolled 127 participants with a median age of 67 years (IQR: 63–71). Postoperative delirium developed in 32 (25%) patients. Before surgery, the patients were screened for global cognitive impairment with the use of the Mini-Mental State Examination Test, and the individuals were asked to perform the CNS Vital Signs battery to investigate 12 specific cognitive domains. The Confusion Assessment Method and the Memorial Delirium Assessment Scale were used to screen for a diagnosis of delirium postoperatively. RESULTS: In multivariate models, a lower score of verbal memory-assessed preoperatively was independently associated with the risk of postoperative delirium development. Other independent predictors of delirium included more advanced age, gender female, depression, postoperative pyrexia, and the presence of extracorporeal circulation. CONCLUSIONS: As decreased verbal memory constitutes an independent risk factor for postoperative delirium, a verbal memory test may be a useful predictor of postoperative delirium development.