The role of apolipoprotein E in cognitive decline after cardiac operation

Background. Recently, Tardiff and colleagues have suggested that the presence of the apolipoprotein E, ε4 allele was associated with increased likelihood of cognitive decline after coronary artery bypass grafting. The objective of the current study was to replicate this earlier work using an increased sample size. The increased sample also enabled an analysis by individual genotype in cognitive decline after coronary artery bypass grafting. Methods. Apolipoprotein E genotyping was performed on 111 individuals undergoing coronary artery bypass grafting. Each participant underwent a battery of nine neuropsychological tests before operation and 4 to 7 weeks after operation. Results. Cognitive decline, assessed by both continuous image change scores and two categoric measures of cognitive deficit, was not significantly associated with either individual apolipoprotein E genotypes or categorization by the presence or absence of the ε4 allele. The examination of potential moderating factors did not alter this finding. Conclusions. This study suggests that the ε4 allele is not associated with cognitive decline in the weeks after coronary artery bypass grafting.