Cognitive changes 5 years after coronary artery bypass grafting - Is thereevidence of late decline?

Objective: To determine the long-term (preoperative to 5 years postoperativ e) and late (1-5 years postoperative) changes in cognitive test performance in patients after coronary artery bypass grafting. Setting: The departments of surgery and neurology at The Johns Hopkins Univ ersity School of Medicine, Baltimore, Md. Patients: A group of 102 patients who completed preoperative and follow-up cognitive testing up to 5 years after coronary artery bypass grafting. Main Outcome Measures: A battery of neuropsychological tests, assessing 8 c ognitive domains (attention, language, verbal and visual memory, visuoconst ruction, executive function, and psychomotor and motor speed),was administe red preoperatively and at 1 month, 1 year, and 5 years postoperatively. Results: Significant changes in neuropsychological test scores from baselin e to 5 years were observed in only 3 of the 8 domains: there were declines in visuoconstruction and psychomotor speed and an improvement in executive function. When the period from baseline to 5 years was divided into 2 inter vals, we found that cognitive test scores generally improved from baseline to 1 year. By contrast, between 1 and 5 years, there was significant declin e in all cognitive domains except for attention and executive function. Som e potential explanatory covariates (demographic, medical history, and surge ry variables) were associated with changes from baseline to 5 years in some cognitive domains, but few covariates were statistically significant in mo re than 1 cognitive domain. Conclusions: The change in cognitive test performance between baseline and 5 years is likely related to several factors, including low baseline perfor mance and practice effects. The significant decline in performance between 1 and 5 years, however, raises the possibility that a late cognitive declin e may be occurring in this population. Additional studies, with the use of a nonsurgical control group, are needed to determine if the observed cognit ive decline is related to bypass surgery itself, normal aging in a populati on with cardiovascular risk factors, or some combination of these and other factors.