Patients with the APOE-ε4 genotype are at increased risk of both vascular dementia and peripheral vascular disease. Patients undergoing major vascular surgery are at particularly high risk of delirium and other, more subtle, changes in cognitive function following surgery. The hypothesis of this trial is that the APOE-ε4 genotype is associated with both delirium and postoperative cognitive dysfunction (POCD).

Inclusion Criteria:

• Age 60 or greater
• Open repair of the abdominal aorta

Exclusion Criteria:

• refusal;
• planned endovascular repair;
• emergency surgery;
• previous diagnosis of dementia, Parkinson's disease, or psychiatric illness;
• active alcohol or substance abuse; and
• physical inability to complete neuropsychometric testing.

Patients 60 years of age or greater undergoing open repair of the abdominal aorta at an academic tertiary care hospital.