Eligibility CriteriaInclusion criteria: Subjects are eligible to participate if they are undergoing TAVR for aortic stenosis at the University of Texas Southwestern Medical Center.
Exclusion Criteria1. The patient cannot or will not provide informed consent.
2. The patient is aged less than 18 years.
3. The patient's pre-procedural hematocrit is less than 25%.
4. The patient has known hepatitis C and/or human immunodeficiency virus infection
5. In the opinion of the principal investigator, the patient will be unlikely to complete long-term follow up for medical or social reasons.