Medical student University of Ottawa Heart Institute Ottawa, Ontario, Canada
Background: Positron emission tomography with computed tomography (PET/CT) is a valuable tool used to guide the diagnosis and management of complex prosthetic valve infectious endocarditis (IE) cases, especially when echocardiography is non-diagnostic. An Endocarditis Team (ET) plays a crucial role in integrating data from such diagnostic testing to improving clinical outcomes of IE. The goal of this study was to (1) assess the impact of PET/CT on the diagnosis and management of IE by the ET, and (2) compare PET/CT to echocardiographic findings.
METHODS AND RESULTS: Patients who were reviewed by the ET from August 2020 to December 2023 at the University of Ottawa Heart Institute and underwent PET/CT for IE evaluation were prospectively included in an Endocarditis Registry, which includes data on management decisions made by the ET, demographics, imaging results, and longitudinal outcomes including mortality, hospital readmissions, and relapses/recurrences. Of 192 patients discussed by the ET, 54 patients underwent PET/CT. Forty were male (74.1%), with a mean age of 64 years (SD = 12.96). Using the modified Duke criteria, PET/CT changed the diagnosis of IE in 12/54 (22.2%) cases including a change from possible to definite in 7 (13%) patients, refuted to possible in 4 patients (7%), and from refuted to definite in 1 (2%) patient. PET/CT changed the management of IE in 13/54 (24.1%) cases, which included changes in antibiotic duration in 7 (53.8%), removal of cardiac implantable electronic devices in 4 (30.8%), and change to surgical treatment in 1 (7.7%). Ten of these cases (76.9%) were PET/CT positive for IE. Of those whose PET/CT scans led to management changes, 6 (46.2%) experienced complications post-discharge, and 4 (30.8%) died within 6 months. However, these patients were critically ill despite optimized antibiotic therapy or CIED removal. In patients who had both PET/CT and transthoracic echocardiography (TTE), 29/47 (62%) of PET/CT were positive whereas only 6/47 (13%) of TTE were positive.
Conclusion: PET/CT changed the management of 15.4% of the patients reviewed by the ET, mostly related to changes in antibiotic duration. PET/CT was able to reclassify a significant proportion of patients with refuted or possible to definite IE who had negative echocardiography, reflecting the higher specificity of PET/CT compared to echocardiography. This study supports considering the use of PET/CT through a multidisciplinary ET to clarify the diagnosis and management when echocardiography is negative or equivocal, and there is ongoing clinical suspicion for IE.
