This is a pilot study in which we will aim to demonstrate successful execution of the imaging protocol and to make observations regarding the calcification activity as measured by 18F-NaF PET/CT and any correlation to 1) valve age and valve type, and 2) subsequent degeneration of aortic valve bioprostheses based upon clinical, echocardiographic and CT parameters.

Additionally, the data will serve as preliminary data to plan a larger study to investigate study objectives.

This five-year pilot study will aim to demonstrate successful execution of the imaging protocol and to make observations regarding the calcification activity as measured by 18F-NaF PET/CT and any correlation to 1) valve age and valve type, and 2) subsequent degeneration of aortic valve bioprostheses based upon clinical, echocardiographic and CT parameters. Techniques that can identify specific increases in calcification activity are therefore likely to provide important insights into predicting the longevity of TAVR valves and guidance towards subsequent interventions.

Twenty patients whom have undergone either TAVR or surgical bioprosthetic aortic valve replacement will be invited to participate in an 18F-NaF PET scan (baseline) and CT scan imaging (baseline and Year 2). Baseline, Year 1 and 2 will also include clinical assessment, labs and echocardiograms. Telephone contact at Years 3, 4, and 5 will provide follow up for major cardiovascular adverse events.

Inclusion Criteria:

• Aged ≥60 years
• Patients between 1 month and 5 years following transcatheter aortic valve replacement (TAVR) or surgical bioprosthetic aortic valve replacement

Exclusion Criteria:

• Inability to provide informed consent
• Creatinine >1.5 mg/dL
• History of severe allergy to iodine contrast agents
• Active atrial fibrillation
• Paget's disease
• Metastatic malignancy