18-F Sodium Fluoride (18F-NaF) PET for the Assessment of Bioprosthetic Aortic Valve Durability and Outcomes

18-F Sodium Fluoride (18F-NaF) PET for the Assessment of Bioprosthetic Aortic Valve Durability and Outcomes

18-F Sodium Fluoride (18F-NaF) Positron Emission Tomography (PET) for the Assessment of Bioprosthetic Aortic Valve Durability and Outcomes

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.

18F-NaF PET-CT scan (at Baseline visit only) Contrast-enhanced CT Scan (at Baseline and Year 2 only) with possible beta-blocker and nitroglycerin, if medically safe.

At baseline a target dose of 125 MBq 18F-NaF will be administered intravenously to all subjects who will then undergo dual cardiac and respiratory-gated PET-CT imaging of the heart and aortic valve. 125ml of iodine-based contrast agent (iohexol [Omnipaque™]) will be given for the CT. Nitroglycerin will be given to increase the size of the coronary arteries and a possible dose of metoprolol may be given to control target heart rate. Repeat contrast-enhanced CT of the heart and aortic valve will be conducted at Year 2 to investigate to investigate whether 18F-NaF activity predicts progression of calcification in prosthetic valves.

Presence of calcification activity will be determined by presence of uptake of the radiotracer, 18F-NaF, on 18F-NaF PET-CT images.

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