The Effects of Anesthesia on Patients Undergoing Surgery for Repair of a Thoracoabdominal Aneurysm.

The Effect of Anesthesia on Potential Cerebrospinal Fluid (CSF) and Serum Markers of Alzheimer's Disease.

Alzheimer's disease represents a growing public health problem in developed countries. Although the pathogenesis is not clearly defined, accumulation of extracellular amyloid, neurofibrillary tangles and neuronal loss are the hallmarks of Alzheimer's disease. The effect of anesthetic agents on changes in these proteins in humans is not well characterized, but in-vitro evidence suggests that anesthetic agents can accelerate potential pathogenic mechanisms, such as increasing amyloid formation or rates of apoptosis in cultured cells and increasing amyloid levels in mice. Human data on the effect of anesthetic agents on amyloid and tau proteins is limited to a small series of 11 patients and showed a significant increase in tau levels after exposure to anesthetics. In this study the investigators propose to measure CSF and serum biomarkers in a population of patients with normal CSF dynamics, who are undergoing surgery for repair of a thoracoabdominal aneurysm. The investigators will also obtain preliminary data on whether changes in CSF levels of these proteins are associated with postoperative delirium or cognitive change.

These will be patients undergoing an open repair of thoracoabdominal aneurysms with or without cardiopulmonary bypass. The will be observational only.

These patients are patients receiving repair of thoracoabdominal aneurysms using stent grafts. These patients will be randomized to receive isoflurane as their primary anesthetic.

These patients are patients receiving repair of thoracoabdominal aneurysms using stent grafts. These patients will be randomized to receive propofol as their primary anesthetic.

Quantitative levels of tau will be measured using ELISA assay technique in pg/ml to compare the differences between the group receiving Propofol and the groups receiving Isoflurane. .

Quantitative levels of amyloid will be measured using ELISA assay technique in pg/ml to compare the differences between the group receiving Propofol and the groups receiving Isoflurane.

Delirium was measured using the Confusion Assessment Method and the Confusion Assessment Method- Intensive Care Unit (CAM-ICU) based upon post-operative location of patient. The patients were divided into to two groups, patients that had an open thoracoabdominal aneurysm repair versus patients that had stenting of their aneurysms. Patients that had stenting of their aneurysms were also randomized to receive either Propofol or Isoflurane as for their anesthetic.

Serum inflammatory markers will be compared per anesthetic group, Propofol versus Isoflurane. A sample of 10 individuals from each group will have biomarkers measured

Inclusion Criteria: age 21-100 years of age Patients presenting for surgical repair of a thoracoabdominal aneurysm Insertion of a CSF spinal drain for clinically indicated reason Exclusion Criteria: Patients with pre-existing delirium Inability to speak and understand English Severe hearing impairment, resulting in inability to converse Pregnancy. Pregnancy status will be assessed using a serum pregnancy test during preoperative evaluation as part of the standard of care.