Diagnostic value of 18F-FDG PET/CT in infective endocarditis

The Evolving Landscape of Infective Endocarditis: Difficult-to-Treat Resistance Bacteria and Novel Diagnostics at the Foreground

Infective endocarditis (IE) is a relatively rare but potentially life-threatening disease characterized by substantial mortality and long-term sequelae among the survivors. In recent decades, a dramatic change in the profile of patients diagnosed with IE has been observed primarily in developed countries, most likely due to an aging population and a recent increase in invasive medical procedures. Nowadays, the typical IE patient is usually older, with complex comorbidities, and a history significant for cardiac disease, including degenerative heart valve disease, prosthetic valves, or cardiovascular implantable electronic devices (CIEDs). Moreover, as patient risk factors change, predisposing them to more healthcare-associated IE, the microbiology of IE is also shifting; there are growing concerns regarding the rise in the incidence of IE caused by difficult-to-treat resistance (DTR) bacteria in at-risk patients with frequent healthcare contact. The present review aims to explore the evolving landscape of IE and summarize the current knowledge on novel diagnostics to ensure timely diagnosis and outline optimal therapy for DTR bacterial IE.

Comparison between Duke, European Society of Cardiology 2015, International Society for Cardiovascular Infectious Diseases 2023, and European Society of Cardiology 2023 criteria for the diagnosis of transcatheter aortic valve replacement-related infective endocarditis

AIMS

Transcatheter aortic valve replacement-related infective endocarditis (TAVR-IE) is associated with a poor prognosis. TAVR-IE diagnosis is challenging, and benefits of the most recent classifications [European Society of Cardiology (ESC)-2015, International Society for Cardiovascular Infectious Diseases (ISCVID)-2023, and ESC-2023] have not been compared with the conventional Duke criteria on this population. The primary objective was to compare the diagnostic value of the Duke, ESC-2015, ISCVID-2023, and ESC-2023 criteria for the diagnosis of TAVR-IE. The secondary objectives were to determine which criteria increase the diagnostic accuracy of each classification and to evaluate in-hospital and 1-year mortality of TAVR-IE.

METHODS AND RESULTS

From January 2015 to May 2022, 92 patients with suspected TAVR-IE were retrospectively included in two French centres, including 82 patients with definite TAVR-IE and 10 patients with rejected TAVR-IE as defined by expert consensus. Duke classification yielded a sensitivity of 65% [95% confidence interval (CI): 53-75%] and a specificity of 100% (95% CI: 69-100%) for the diagnosis of TAVR-IE. ESC-2015 classification increased Duke criterion sensitivity from 65 to 73% (P = 0.016) but decreased specificity from 100 to 90%. ISCVID-2023 and ESC-2023 also increased Duke criterion sensitivity from 65 to 76% (P = 0.004) and 77% (P = 0.002), respectively, but also decreased specificity from 100 to 90%. A positive 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) was the most helpful criterion, as 10 patients (11%) were correctly reclassified. In-hospital mortality after TAVR-IE was 21% and 1-year mortality was 38%.

CONCLUSION

A multimodality imaging approach, including 18F-FDG PET/CT and gated cardiac CT, is the cornerstone of TAVR-IE diagnosis and explains the higher sensitivity of ESC-2015 and recent classifications compared with Duke criteria.

Current trends and challenges in infective endocarditis

PURPOSE OF REVIEW

Infective endocarditis (IE) is a complex disease with increasing global incidence. This review explores recent trends in IE infection patterns, including healthcare-associated IE (HAIE), drug-use-associated IE (DUA-IE), multidrug-resistant organisms (MDROs), and challenges in managing prosthetic valve and device-related infections.

RECENT FINDINGS

Staphylococcus aureus has emerged as the leading cause of IE, especially in HAIE and DUA-IE cases. Increasingly prevalent MDROs, such as methicillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci, pose further clinical challenges. Advances in molecular diagnostics have improved the detection of culture-negative endocarditis. The introduction of the AngioVAC percutaneous aspiration device promises to change the management of right and possibly some left sided IE. Multidisciplinary team management and early surgery have demonstrated improved outcomes including partnerships with psychiatry and addictions services for those with intravenous DUA-IE.

SUMMARY

IE presents significant diagnostic and therapeutic challenges due to evolving infection patterns, MDROs, and HAIE. Early diagnosis using advanced imaging, appropriate early antimicrobial therapy, and multidisciplinary care, including timely surgery, are critical for optimizing patient outcomes.

Use of whole body PET scan in patients with infective endocarditis may impact care of those with intravascular devices: results from a comparative retrospective cohort study

Background

Whole body 18F-fluorodeoxyglucose positron emission tomography/CT (WBP) may be an important tool for the management of infective endocarditis (IE) by identifying areas of occult primary or metastatic infection. However, the optimal use of this study in patients with IE is unknown.

Objectives

Compare clinical characteristics and outcomes in patients who did and did not have WBP as part of their endocarditis management, and describe the impact that WBP has on the management of IE.

Design

Retrospective cohort study.

Methods

We performed a protocolized chart review of hospitalized patients with suspected IE who were discussed by a multidisciplinary endocarditis team at a tertiary care center between June 2018 and January 2022.

Results

Among 427 patients, there were 114 patients (26.7%) in the WBP group and 313 patients (73.3%) in the non-WBP group. The WBP group was significantly more likely to have end-stage renal disease, intracardiac prostheses, and cardiac devices, while the non-WBP group was more likely to have flail leaflet or paravalvular abscesses. There were no statistically significant differences in mortality, hospital readmission, or length of stay between the two cohorts. The WBP group was more likely to receive longer antibiotic courses and had higher rates of suppressive antibiotics following treatment courses (p < 0.001). The use of WBP directly affected management in 44.6% of those patients, especially when performed to evaluate intravascular prostheses and grafts. Changes in management included further workup, performance of a source control procedure, or a change in the antibiotic regimen.

Conclusion

WBP plays an important role in identifying metastatic foci of infection and directly impacting the management of patients with confirmed or suspected endocarditis. Infected intravascular prostheses were effectively identified via WBP, and as a result, these patients were prescribed longer courses of antibiotics and suppressive antibiotics.

Update on the epidemiology, diagnosis, and management of infective endocarditis: A review

Despite advancements in the diagnosis and treatment of infective endocarditis (IE), the burden of IE has remained relatively high over the past decade. With an ageing population and an increasing proportion of healthcare-associated IE, the epidemiology of IE has undergone significant changes. Staphylococcus aureus has evolved as the most common causative microorganism, even in most low- and middle-income countries. Several imaging modalities and novel microbiological tests have emerged to facilitate the diagnosis of IE. Outpatient parenteral antibiotic treatment and oral step-down antibiotic treatment have become new trends for the management of IE. Early surgical intervention, particularly within seven days, should be considered in cases of IE with appropriate surgical indications. We comprehensively review the updated epidemiology, microbiology, diagnosis, and management of IE.

Infective Endocarditis in Patients with End-Stage Renal Disease on Dialysis: Epidemiology, Risk Factors, Diagnostic Challenges, and Management Approaches

Infective endocarditis (IE) poses a significant clinical challenge, especially among patients with end-stage renal disease (ESRD) undergoing dialysis, and is associated with high morbidity and mortality rates. This review provides a contemporary discussion of the epidemiology, risk factors, diagnostic challenges, and management strategies for IE among ESRD patients, including a literature review of recent studies focused on this vulnerable population. The review highlights the multifactorial nature of IE risk in ESRD patients, emphasizing the roles of vascular access type, dialysis modality, and comorbid conditions. It also explores the diagnostic utility of different imaging modalities and the importance of a multidisciplinary approach in managing IE, including both medical and surgical interventions. The insights from this review aim to contribute to the improvement of patient outcomes through early recognition, appropriate antimicrobial therapy, and timely surgical intervention when necessary.

18F-FDG PET/CT and Radiolabeled Leukocyte SPECT/CT Imaging for the Evaluation of Cardiovascular Infection in the Multimodality Context: ASNC Imaging Indications (ASNC I2) Series Expert Consensus Recommendations From ASNC, AATS, ACC, AHA, ASE, EANM, HRS, IDSA, SCCT, SNMMI, and STS

This document on cardiovascular infection, including infective endocarditis, is the first in the American Society of Nuclear Cardiology Imaging Indications (ASNC I2) series to assess the role of radionuclide imaging in the multimodality context for the evaluation of complex systemic diseases with multisocietal involvement including pertinent disciplines. A rigorous modified Delphi approach was used to determine consensus clinical indications, diagnostic criteria, and an algorithmic approach to diagnosis of cardiovascular infection including infective endocarditis. Cardiovascular infection incidence is increasing and is associated with high morbidity and mortality. Current strategies based on clinical criteria and an initial echocardiographic imaging approach are effective but often insufficient in complicated cardiovascular infection. Radionuclide imaging with fluorine-18 fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (CT) and single photon emission computed tomography/CT leukocyte scintigraphy can enhance the evaluation of suspected cardiovascular infection by increasing diagnostic accuracy, identifying extracardiac involvement, and assessing cardiac implanted device pockets, leads, and all portions of ventricular assist devices. This advanced imaging can aid in key medical and surgical considerations. Consensus diagnostic features include focal/multifocal or diffuse heterogenous intense 18F-FDG uptake on valvular and prosthetic material, perivalvular areas, device pockets and leads, and ventricular assist device hardware persisting on non-attenuation corrected images. There are numerous clinical indications with a larger role in prosthetic valves, and cardiac devices particularly with possible infective endocarditis or in the setting of prior equivocal or non-diagnostic imaging. Illustrative cases incorporating these consensus recommendations provide additional clarification. Future research is necessary to refine application of these advanced imaging tools for surgical planning, to identify treatment response, and more.

18F-FDG PET/CT and radiolabeled leukocyte SPECT/CT imaging for the evaluation of cardiovascular infection in the multimodality context: ASNC Imaging Indications (ASNC I2) Series Expert Consensus Recommendations from ASNC, AATS, ACC, AHA, ASE, EANM, HRS, IDSA, SCCT, SNMMI, and STS

This document on cardiovascular infection, including infective endocarditis, is the first in the American Society of Nuclear Cardiology Imaging Indications (ASNC I2) series to assess the role of radionuclide imaging in the multimodality context for the evaluation of complex systemic diseases with multi-societal involvement including pertinent disciplines. A rigorous modified Delphi approach was used to determine consensus clinical indications, diagnostic criteria, and an algorithmic approach to diagnosis of cardiovascular infection including infective endocarditis. Cardiovascular infection incidence is increasing and is associated with high morbidity and mortality. Current strategies based on clinical criteria and an initial echocardiographic imaging approach are effective but often insufficient in complicated cardiovascular infection. Radionuclide imaging with 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (CT) and single photon emission computed tomography/CT leukocyte scintigraphy can enhance the evaluation of suspected cardiovascular infection by increasing diagnostic accuracy, identifying extracardiac involvement, and assessing cardiac implanted device pockets, leads, and all portions of ventricular assist devices. This advanced imaging can aid in key medical and surgical considerations. Consensus diagnostic features include focal/multi-focal or diffuse heterogenous intense 18F-FDG uptake on valvular and prosthetic material, perivalvular areas, device pockets and leads, and ventricular assist device hardware persisting on non-attenuation corrected images. There are numerous clinical indications with a larger role in prosthetic valves, and cardiac devices particularly with possible infective endocarditis or in the setting of prior equivocal or non-diagnostic imaging. Illustrative cases incorporating these consensus recommendations provide additional clarification. Future research is necessary to refine application of these advanced imaging tools for surgical planning, to identify treatment response, and more.

18F-FDG PET/CT and radiolabeled leukocyte SPECT/CT imaging for the evaluation of cardiovascular infection in the multimodality context: ASNC Imaging Indications (ASNC I2) Series Expert Consensus Recommendations from ASNC, AATS, ACC, AHA, ASE, EANM, HRS, IDSA, SCCT, SNMMI, and STS

This document on cardiovascular infection, including infective endocarditis, is the first in the American Society of Nuclear Cardiology Imaging Indications (ASNC I2) series to assess the role of radionuclide imaging in the multimodality context for the evaluation of complex systemic diseases with multi-societal involvement including pertinent disciplines. A rigorous modified Delphi approach was used to determine consensus clinical indications, diagnostic criteria, and an algorithmic approach to diagnosis of cardiovascular infection including infective endocarditis. Cardiovascular infection incidence is increasing and is associated with high morbidity and mortality. Current strategies based on clinical criteria and an initial echocardiographic imaging approach are effective but often insufficient in complicated cardiovascular infection. Radionuclide imaging with 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (CT) and single photon emission computed tomography/CT leukocyte scintigraphy can enhance the evaluation of suspected cardiovascular infection by increasing diagnostic accuracy, identifying extracardiac involvement, and assessing cardiac implanted device pockets, leads, and all portions of ventricular assist devices. This advanced imaging can aid in key medical and surgical considerations. Consensus diagnostic features include focal/multi-focal or diffuse heterogenous intense 18F-FDG uptake on valvular and prosthetic material, perivalvular areas, device pockets and leads, and ventricular assist device hardware persisting on non-attenuation corrected images. There are numerous clinical indications with a larger role in prosthetic valves, and cardiac devices particularly with possible infective endocarditis or in the setting of prior equivocal or non-diagnostic imaging. Illustrative cases incorporating these consensus recommendations provide additional clarification. Future research is necessary to refine application of these advanced imaging tools for surgical planning, to identify treatment response, and more.

The Role of Positron Emission Tomography in Advancing the Understanding of the Pathogenesis of Heart and Vascular Diseases

Cardiovascular disease remains the leading cause of morbidity and mortality worldwide. For developing new therapies, a better understanding of the underlying pathology is required. Historically, such insights have been primarily derived from pathological studies. In the 21st century, thanks to the advent of cardiovascular positron emission tomography (PET), which depicts the presence and activity of pathophysiological processes, it is now feasible to assess disease activity in vivo. By targeting distinct biological pathways, PET elucidates the activity of the processes which drive disease progression, adverse outcomes or, on the contrary, those that can be considered as a healing response. Given the insights provided by PET, this non-invasive imaging technology lends itself to the development of new therapies, providing a hope for the emergence of strategies that could have a profound impact on patient outcomes. In this narrative review, we discuss recent advances in cardiovascular PET imaging which have greatly advanced our understanding of atherosclerosis, ischemia, infection, adverse myocardial remodeling and degenerative valvular heart disease.

18F-FDG-Based Radiomics and Machine Learning: Useful Help for Aortic Prosthetic Valve Infective Endocarditis Diagnosis?

BACKGROUND

Fluorine-18 fluorodeoxyglucose (¹⁸F-FDG)-positron emission tomography (PET)/computed tomography (CT) results in better sensitivity for prosthetic valve endocarditis (PVE) diagnosis, but visual image analysis results in relatively weak specificity and significant interobserver variability.

OBJECTIVES

The primary objective of this study was to evaluate the performance of a radiomics and machine learning-based analysis of ¹⁸F-FDG PET/CT (PET-ML) as a major criterion for the European Society of Cardiology score using machine learning as a major imaging criterion (ESC-ML) in PVE diagnosis. The secondary objective was to assess performance of PET-ML as a standalone examination.

METHODS

All ¹⁸F-FDG-PET/CT scans performed for suspected aortic PVE at a single center from 2015 to 2021 were retrospectively included. The gold standard was expert consensus after at least 3 months' follow-up. The machine learning (ML) method consisted of manually segmenting each prosthetic valve, extracting 31 radiomics features from the segmented region, and training a ridge logistic regressor to predict PVE. Training and hyperparameter tuning were done with a cross-validation approach, followed by an evaluation on an independent test database.

RESULTS

A total of 108 patients were included, regardless of myocardial uptake, and were divided into training (n = 68) and test (n = 40) cohorts. Considering the latter, PET-ML findings were positive for 13 of 22 definite PVE cases and 3 of 18 rejected PVE cases (59% sensitivity, 83% specificity), thus leading to an ESC-ML sensitivity of 72% and a specificity of 83%.

CONCLUSIONS

The use of ML for analyzing ¹⁸F-FDG-PET/CT images in PVE diagnosis was feasible and beneficial, particularly when ML was included in the ESC 2015 criteria. Despite some limitations and the need for future developments, this approach seems promising to optimize the role of ¹⁸F-FDG PET/CT in PVE diagnosis.