Prognosis and follow-up of patients with prosthetic valve endocarditis treated conservatively in relation to WBC-SPECT imaging.

BACKGROUND: Our objective was to evaluate in patients with prosthetic valve endocarditis (PVE) treated conservatively, the prognostic value of white blood cell (WBC) signal intensity on SPECT and to describe the evolution of the WBC signal under antibiotics. METHODS: Patients with PVE treated conservatively and positive WBC-SPECT imaging were identified retrospectively. Signal intensity was classified as intense if equal to or higher, or mild if lower, than the liver signal. Clinical, biological, imaging and follow-up information were collected from medical files. RESULTS: Among 47 patients, WBC signal was classified as intense in 10 patients and as mild, in 37. The incidence of the primary composite endpoint (death, late cardiac surgery, or relapse) was significantly higher in patients with intense vs. mild signal (90% vs. 11%). Twenty-five patients underwent a second WBC-SPECT imaging during follow-up. The prevalence of WBC signal decreased progressively from 89% between 3 and 6 weeks to 42% between 6 and 9 weeks and 8% more than 9 weeks after initiation of antibiotics. CONCLUSIONS: In patients with PVE treated conservatively, intense WBC signal was associated with poor outcome. WBC-SPECT imaging appears as an interesting tool for risk stratification and to monitor locally the efficacy of antibiotic treatment.

Diagnostic performance of White Blood Cell SPECT imaging against intra-operative findings in patients with a suspicion of prosthetic valve endocarditis.

AIM: The objective of this study was to evaluate the diagnostic performance of white blood cells (WBC)-SPECT imaging in patients with suspicion of prosthetic valve endocarditis (PVE) against intra-operative findings. METHODS: 36 consecutive patients who underwent cardiac surgery 30 days after WBC-SPECT imaging were identified retrospectively. Clinical, imaging, and biological results were collected from reports. WBC-SPECT results were classified as positive or negative and, if positive, the intensity of signal graded as intense or mild. Lesions observed during cardiac surgery were collected from surgeons' reports. RESULTS: The 20 patients with positive WBC-SPECT study had confirmed PVE intra-operatively. Patients with intense signal on WBC-SPECT had high prevalence of abscesses (83%) compared to patients with only mild signal (12%). The three patients with negative WBC-SPECT but confirmed PVE had longer duration of antibiotic treatment before imaging and had no perivalvular abscess. Sensitivity, specificity, positive predictive and negative values, and accuracy of WBC-SPECT were measured at 87%, 100%, 100%, 81%, and 92%, respectively. Addition of WBC-SPECT results to the modified Duke score helped re-classify correctly 25% of patients from possible to definite PVE. CONCLUSION: In patients with suspicion of PVE, WBC-SPECT imaging provides excellent diagnostic performance against intra-operative findings.

Hypermetabolism of the spleen or bone marrow is an additional albeit indirect sign of infective endocarditis at FDG-PET.

PURPOSE: This study aimed at determining the diagnostic implications of indirect signs of infection at FDG-PET-i.e., hypermetabolisms of the spleen and/or bone marrow (HSBM)-when documented in patients with known or suspected infective endocarditis (IE). METHODS: HSBM were defined by higher mean standardized uptake values comparatively to that of the liver on FDG-PET images from patients with a high likelihood of IE and prospectively included in a multicenter study. RESULTS: Among the 129 included patients, IE was ultimately deemed as definite in 88 cases. HSBM was a predictor of definite IE (P = 0.014; odds ratio (OR) 3.2), independently of the criterion of an abnormal cardiac FDG uptake (P = 0.0007; OR 9.68), and a definite IE was documented in 97% (29/30) of patients showing both HSBM and abnormal cardiac uptake, 78% (7/9) of patients with only abnormal cardiac uptake, 67% (42/63) of patients with only HSBM, and 37% (10/27) of patients with neither one. CONCLUSION: In this cohort with a high likelihood of IE, HSBM is an additional albeit indirect sign of IE, independently of the criterion of an abnormal cardiac uptake, and could reinforce the suspicion of IE in the absence of any other infectious, inflammatory, or malignant disease.

Cardiac denervation evidenced by MIBG occurs earlier than amyloid deposits detection by diphosphonate scintigraphy in TTR mutation carriers.

PURPOSE: Cardiac involvement in familial transthyretin (TTR) amyloidosis is of major prognostic value, and the development of early-diagnostic tools that could trigger the use of new disease-modifying treatments is crucial. The aim of our study was to compare the respective contributions of 99mTc-diphosphonate scintigraphy (DPD, detecting amyloid deposits) and 123I-MIBG (MIBG, assessing cardiac sympathetic denervation) in patients with genetically proven TTR mutation referred for the assessment of cardiac involvement. METHODS: We prospectively studied 75 consecutive patients (classified as symptomatic or asymptomatic carriers), using clinical evaluation, biomarkers (troponin and BNP), echocardiography, and nuclear imaging. Patients were classified as having normal heart-to-mediastinum (HMR) MIBG uptake ratio 4 h after injection (defined by HM4 ≥ 1.85) or abnormal HM4 < 1.85, and positive DPD uptake (grade ≥ 1 of Perugini classification) or negative DPD uptake. RESULTS: Among 75 patients, 49 (65%) presented with scintigraphic sympathetic cardiac denervation and 29 (39%) with myocardial diphosphonate uptake. When MIBG was normal, DPD was negative except for two patients. Age was an independent predictor of abnormal scintigraphic result of both MIBG and DPD (HR 1.08 and 1.15 respectively), whereas echocardiographic-derived indicators of increased left ventricular filling pressure (E/e' ratio) was an independent predictor of abnormal MIBG (HR 1.33) and global longitudinal strain of positive DPD (HR 1.45). In asymptomatic patients (n = 31), MIBG was abnormal in 48% (n = 15) among whom 50% had a normal DPD; all those with a normal MIBG (n = 16) had a normal DPD. CONCLUSIONS: In TTR mutation carriers, cardiac sympathetic denervation evidenced by decreased MIBG uptake is detected earlier than amyloid burden evidenced by DPD. These results raise the possibility of a diagnostic role for MIBG scintigraphy at an early stage of cardiac involvement in TTR-mutated carriers, in addition to its well-established prognostic value.

18F-FDG-PET/CT Imaging to Diagnose Septic Emboli and Mycotic Aneurysms in Patients with Endocarditis and Cardiac Device Infections.

PURPOSE OF REVIEW: This review analyzes recent studies evaluating the diagnostic value of 18F-FDG-PET/CT for the detection of peripheral emboli and secondary infectious foci in patients with infective endocarditis and cardiac device infections. RECENT FINDINGS: Detection of extracardiac septic localizations in patients with infective endocarditis and cardiac device infections is crucial, as it may impact the diagnosis, prognosis, and therapeutic management. Recent literature substantiated the clinical usefulness of 18F-FDG-PET/CT in this setting. 18F-FDG-PET/CT has proven its high diagnostic value for the detection of peripheral emboli in patients with infective endocarditis and cardiac device infections, substantially affecting patients' outcome and treatment. A multimodal approach, combining the high sensitivity of 18F-FDG-PET/CT with morphological imaging seems promising.