The purpose of the study is to determine if a new blood test can help the doctor determine if there is brain injury or ischemia. Ischemia occurs when not enough oxygen gets to the brain. In this study the investigators are analyzing your blood for a new test that might help doctors decide if symptoms are from a neurologic problem.

We will compare a new blood test with routine tests that the doctor will order as part of your normal care. This study will measure new biomarkers (biomarker is a specific distinguishing feature used to measure or indicate the effects or progress of a disease or condition) of neurologic stress called xanthine, hypoxanthine, and inosine. Blood will be drawn as a part of the study to measure these biomarker levels in your blood. This blood will be analyzed i the laboratory at Virginia Commonwealth University and possibly at a future date at another institution. No names will be associated with the blood sample

Inclusion Criteria:

• Men and Women over age of 18 non
• Women who are not pregnant
• Subject who are not prisoners
• Subjects presenting to the operation room for a Carotid artery stenting procedure
• Hemoglobin greater than or equal to 11mg/dl
• Subjects who speak english
• Subjects 18 years of age or older

Exclusion Criteria:

• Hemoglobin less than 11mg/dl
• Women who are pregnant
• Children under age of 18
• Prisoners
• Non English

Patients scheduled for Carotid Stenting Procedure at Virginia Commonwealth University