Neurocognitive outcomes 3 years after coronary artery bypass graft surgery: A controlled study

Background. Cardiopulmonary bypass has been implicated in the late cognitive decline that has been reported after coronary artery bypass graft (CABG) surgery. Because most studies did not include a control group, a causal link of such decline with the use of cardiopulmonary bypass has not been established. Methods. We compared changes in cognitive performance from baseline to 3 years in patients undergoing on-pump CABG (n = 152) with those of three control groups: patients with off-pump surgery (n = 75); with diagnosed coronary artery disease but no surgery (n = 99); and without coronary artery disease risk factors (n = 69). Neuropsychological performance was assessed by standardized tests of attention, language, verbal and visual memory, visuospatial, executive function, and psychomotor and motor speed. Results. Relative to their baseline performance, no group had significantly lower performance at 36 months for any of the cognitive domains. From 12 to 36 months, there were no statistically significant differences in the degree of change between the on- and off-pump surgery groups. There was a trend toward mild decline in some cognitive domains, but overall differences among groups in degree of change over time were not statistically significant. Conclusions. We found a mild but nonsignificant trend toward late postoperative cognitive decline for all study groups with coronary artery disease, but no significant differences in the degree of late postoperative cognitive decline after on- pump compared with off-pump surgery. These findings suggest that previously reported late decline after bypass surgery is not specific to use of cardiopulmonary bypass.