Endovascular repair of aortic aneurysm and endovascular treatment of arteriosclerosis obliterans of lower extremities are two kinds of common surgeries in the investigators' hospital. The effects of anesthetic agents on postoperative outcome, especially cognitive function, are not clear. In this study investigators propose to measure postoperative cognitive function and other outcome of patients who are undergoing these two kinds of surgeries, and try to identify whether there is an association between different kinds of anesthetics and postoperative outcome. Investigators will also observe whether changes in plasma levels of VEGF, TGF-1, TNF-α, IL-1β, and IL-6, are associated with postoperative delirium or cognitive change.

Inclusion Criteria:

• age 18-100 years of age
• Patients presenting for Endovascular repair of aortic aneurysm and endovascular treatment of arteriosclerosis obliterans of lower extremities

Exclusion Criteria:

• Patients with pre-existing delirium
• Inablility to converse