title: A prospective cohort study evaluating associations among delirium, postoperative cognitive dysfunction, and apolipoprotein E genotype following open aortic repair.
abstract: BACKGROUND
  Patients undergoing major vascular surgery are at high risk of postoperative delirium and postoperative cognitive dysfunction (POCD). Apolipoprotein E (APOE) is involved in central acetylcholine synthesis, and patients bearing the ε4 genotype (APOE-ε4) are at increased risk of both vascular dementia and peripheral vascular disease. The purpose of this study was to evaluate the associations among delirium, POCD, and APOE-ε4 in patients undergoing open aortic repair.
  
  
  METHODS
  Following Research Ethics Board approval and written informed consent, we recruited a cohort of patients ≥ 60 yr of age undergoing open aortic repair. Apolipoprotein E genotyping and a battery of nine neuropsychometric (NP) tests were performed prior to surgery. Delirium was assessed on postoperative days two, four, and discharge using the Confusion Assessment Method. Neuropsychometric testing was repeated at discharge and again three months following surgery. A group of non-surgical patients was used to adjust NP scores using reliable change index methodology. Logistic regression was used to evaluate independent predictors of both delirium and POCD.
  
  
  RESULTS
  Eighty-eight patients underwent surgery, 78 completed NP testing on discharge, and sixty-nine completed NP testing at three months. Delirium was noted in 36% of patients after surgery, while POCD was noted in 62% at discharge and 6% at three months. Delirium predicted POCD at discharge (odds ratio 2.86; 95% confidence intervals 0.99 to 8.27) but not at three months. Apolipoprotein E-ε4 genotype was not associated with either delirium or POCD following adjustment for covariates.
  
  
  CONCLUSIONS
  Both delirium and POCD are common following open aortic repair; however, the APOE genotype did not predict either condition. This trial has been registered with ClinicalTrials.gov (NCT00911677).
authors.affiliation: Department of Anesthesiology, The Ottawa Hospital, 1053 Carling Avenue, Box 249C, Ottawa, ON K1Y 4E9, Canada. glbryson@ottawahospital.on.ca
authors.forename: Gregory L
authors.initials: GL
authors.lastname: Bryson
authors.forename: Anna
authors.initials: A
authors.lastname: Wyand
authors.forename: Denise
authors.initials: D
authors.lastname: Wozny
authors.forename: Laura
authors.initials: L
authors.lastname: Rees
authors.forename: Monica
authors.initials: M
authors.lastname: Taljaard
authors.forename: Howard
authors.initials: H
authors.lastname: Nathan
mesh_terms: D000368:Aged; D001012:Aorta, Abdominal / Q000601:surgery*; D053327:Apolipoprotein E4 / Q000235:genetics*; D003072:Cognition Disorders / Q000209:etiology*; D015331:Cohort Studies; D003693:Delirium / Q000209:etiology*; D005260:Female; D005838:Genotype; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000209:etiology*; D011446:Prospective Studies; D012306:Risk
chemical_list: D053327:Apolipoprotein E4