Recurrent Culture-Negative Prosthetic Valve Endocarditis Diagnosed by Multimodality Imaging

Prosthetic valve endocarditis (PVE) remains challenging to diagnose and is associated with poor long-term outcomes, particularly when blood cultures are negative.

We describe recurrent culture-negative PVE diagnosed using multimodality imaging and tissue molecular diagnostics. A 50-year-old man with prior bioprosthetic aortic and mitral valve replacement, transcatheter mitral valve-in-valve implantation, and an atrial septal occluder presented with acute limb ischemia due to embolization. Blood cultures were negative, and transesophageal echocardiography and cardiac computed tomography favored thrombus over vegetation. Fluorodeoxyglucose positron emission tomography-computed tomography (FDG PET-CT) demonstrated abnormal tracer uptake involving both prosthetic valves and septal occluder, consistent with infection. The patient underwent redo mechanical aortic and mitral valve replacement with device explantation. Pathology confirmed endocarditis, and tissue polymerase chain reaction identified Streptococcus sanguinis.

This case highlights the diagnostic value of FDG PET-CT in recurrent culture-negative PVE.

FDG PET-CT and molecular diagnostics aid in the diagnosis of culture-negative prosthetic and device-related endocarditis. Longitudinal surveillance is important in patients with multiple intracardiac prostheses.