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

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.