Characterization of RadiOlabeled Tracer Uptake Pattern in Noninfected Transcatheter Aortic Valves.

Study Overview
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Brief Summary
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Therefore, the objective of the study is to characterize the pattern of radiolabeled tracer (18F-FDG) uptake in noninfected transcatheter heart valves in early follow-up after transcatheter aortic valve replacement (TAVR).

Detailed Description
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Diagnostic accuracy of Infective endocarditis (IE) is commonly challenging. Current clinical guidelines recommend the use of the modified Duke criteria, based on clinical, echocardiographic and biological findings, as well as the results of blood cultures and serologies. Advances in imaging techniques have resulted in an improvement in the identification of endocardial involvements and extracardiac complications of IE. Thus, recent works have demonstrated that 18F-FDG PET/CT and radiolabeled leucocyte SPECT/CT may improve the detection of silent endocardial lesions. The sites of radiotracer accumulation show regions of a high metabolic activity due to an inflammation or infection process. It is well known that, in surgical prosthetic valves, a mild radiotracer uptake in the perivalvular area may occur in the absence of infection and could therefore be considered as a normal pattern, particularly early after valve replacement. However, evidence of this phenomenon is lacking regarding transcatheter heart valves and the factors used to distinguish between normal and abnormal patterns of radiolabeled tracer are not standardized. The hypothesis is that patients undergoing transcatheter aortic valve replacement (TAVR) show a radiolabeled tracer (18F-FDG) uptake around the prosthesis despite the absence of IE. Moreover, the uptake pattern might vary between different platforms. Therefore, the objective of the study is to characterize the pattern of radiolabeled tracer uptake in noninfected transcatheter heart valves in early follow-up after TAVR. This will be a pilot study including 30 patients after TAVR procedure.

Official Title
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Characterization of Radiolabeled Tracer Uptake Pattern in Noninfected Transcatheter Aortic Valves. The COUNT Study. A Prospective, Observational Study.

Conditions
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Infective Endocarditis

Intervention / Treatment
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* Radiation: 18F-FDG PET/CT


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients >18-year-old undergoing TAVR procedure with Edwards Sapien 3 and Core Valve Evolut R devices. Informed written consent Exclusion Criteria: Inability to provide signed informed consent. Patients with definitive or possible IE according to modified Duke criteria and current clinical guidelines for the management of IE. Any contraindication for 18F-FDG PET/CT. Any condition making it unlikely the patient will be able to complete the protocol procedures and follow-up visits.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Edwards Sapien 3<br>Patients who underwent transcatheter aortic valve replacement with the Edwards Sapien 3 valve | Radiation: 18F-FDG PET/CT<br>* 18F-FDG PET/CT and blood cultures will be performed at 3-month follow-up after TAVR Patients with positive 18F-FDG PET/CT (moderate or intense radiolabeled tracer uptake) will be scheduled for a second 18F-FDG PET/CT at 6-month follow-up.<br>|
| Core Valve Evolut R<br>Patients who underwent transcatheter aortic valve replacement with the Core Valve Evolut R valve | Radiation: 18F-FDG PET/CT<br>* 18F-FDG PET/CT and blood cultures will be performed at 3-month follow-up after TAVR Patients with positive 18F-FDG PET/CT (moderate or intense radiolabeled tracer uptake) will be scheduled for a second 18F-FDG PET/CT at 6-month follow-up.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Radiolabeled tracer uptake grade (intense, moderate, mild or absent) in the prosthetic and periprosthetic areas. | Visual analysis grading the radiolabeled tracer molecules uptake in the prosthetic and periprosthetic areas as intense, moderate, mild or absent. This visual analysis will be defined whether the PET/CT was positive (intense/moderate) or negative (mild/absent). | 3 months after TAVR | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Maximal standardized uptake value (SUVmax) using an average of 3 measurements from 3 volumes of interest (5mm3) introduced in the prosthetic region at equal distances from each other. | The intensity of the radiolabeled tracer uptake will be determined by measuring the maximal standardized uptake value (SUVmax)), which is obtained by normalizing the tissue concentration of the radiolabeled tracer activity and the patient's weight. SUVmax will be calculated using an average of 3 measurements from 3 volumes of interest (5mm3) introduced in the prosthetic region at equal distances from each other. The prosthetic valve-to-background ratio will be calculated by dividing the prosthetic valve SUV max by the atrial blood SUVmax. | 3 months after TAVR | 
| Differences in radiolabeled tracer uptake grade in the prosthetic and periprosthetic areas between the Edwards valve versus the CoreValve valve. | Differences in radiolabeled tracer uptake pattern with different valves: Edwards THV vs CoreValve THV | 3 months after TAVR | 
| Correlation between radiolabeled tracer uptake grade and time from TAVR | Relationship between radiolabeled tracer uptake and time from the procedure | 3 months after TAVR | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Transcatheter aortic valve replacement, Infective endocarditis, Radionuclide imaging, Radiolabeled tracer uptake pattern