Mycotic aortic aneurysms: characteristic macroscopic findings in a case series.

Infected or mycotic aortic aneurysms (MAAs) are a rare type of aneurysms. Due to the high risk of rupture, MAAs are life-threatening conditions. Early diagnosis and treatment are necessary, yet MAAs are usually found coincidentally. We report 10 patients with MAAs in whom macroscopically, similar coined-sized lesions of the inner aortic wall were seen in all cases. When a coin-sized lesion in the inner aortic wall is seen during open surgical repair of an aortic aneurysm, the surgeon should consider an infectious cause. Microbiological tissue samples should be collected, and additional targeted antibiotic therapy should be started.

Surviving the nonsurvivable combination of a mycotic aneurysm progressing into a concomitant aorto-bronchial- and aorto-esophageal fistula, a case report.

BACKGROUND: Aortic mycotic aneurysms are a rare but life-threatening condition and may be associated with aorto-bronchial- and aorto-esophageal fistulas. Although both very rare, they carry a high mortality and require (urgent) surgical intervention. Surviving all three conditions concomitantly is extraordinary. We describe a patient who underwent staged repair of such combined defects.

Postoperative Inflammation and Fever After Elective Aortic Valve and Aortic Root Replacement: A Retrospective Cohort Study.

Background: Fever after cardiac surgery is common. More knowledge of postoperative fever could lead to better patient selection for diagnostic workup and empirical antibiotic treatment. We aimed to analyze the postoperative course of inflammation and fever after elective aortic valve and aortic root replacement. Methods: In a retrospective single-center cohort study, we included 3 groups of patients after elective cardiac surgery: aortic root with aortic valve replacement (Bentall procedure, from 2014 to 2021), valve-sparing root replacement (VSRR, from 2014 to 2021), and isolated surgical aortic valve replacement (SAVR, from 2018 to 2021). Exclusion criteria were age <18 years, cardiac surgery other than described, use of deep-hypothermic circulatory arrest, reoperations, and preexisting infections. Primary outcome measure was the number of patients per group with postoperative fever (≥38°C). Secondary outcome measures were the percentage of patients per group with infections and outcome. Results: Among 307 patients included (76 Bentall, 40 VSRR, 191 SAVR), 71% had postoperative fever. Fever occurred significantly more often in the Bentall (84%) and VSRR group (83%) compared with patients after SAVR (64%, P = .001). Seventeen patients had fever due to infection versus 202 with diagnoses of postoperative inflammation. In case of infection, fever was significantly higher (38.8°C vs 38.4°C, P = .03), and both the number of days with fever and hospital admission duration were significantly longer. Conclusions: Postoperative fever is more often observed after Bentall procedure and VSRR compared to SAVR. In diagnoses of infection, there is a higher and prolonged fever.

Clinically unsuspected orthopedic implants during S. aureus bacteremia do not require additional diagnostic work-up.

PURPOSE: To assess the likelihood of occult infection in patients with clinically unsuspected orthopedic implants during Staphylococcus aureus bacteremia (SAB). METHODS: In a retrospective study in two Dutch hospitals, we included all patients with SAB between 2013 and 2020 with one or more orthopedic implants in whom [18F]FDG-PET/CT was performed. The primary outcome was the percentage of patients who had an orthopedic implant-related infection by S. aureus. We also compared clinical parameters in patients with clinically suspected and unsuspected implants. RESULTS: Fifty-five of 191 (29%) orthopedic implants in 118 SAB patients included had clinical signs of infection. Of all 136 unsuspected implants, 5 (3%, all arthroplasties), showed increased [18F]FDG uptake around the prosthesis on [18F]FDG-PET/CT. The clinical course of these patients without clinically overt infection or relapse of bacteremia during follow-up of a median of 48 months (range 0-48), however, argued against prosthetic joint infection. CONCLUSION: Although orthopedic implants are evidently a risk factor for metastatic infection during SAB, the absence of clinical symptoms obviate the need of additional investigations or prolonged antibiotic treatment.

Redefining Staphylococcus aureus bacteremia: A structured approach guiding diagnostic and therapeutic management.

The current duration of therapy in patients with Staphylococcus aureus bacteremia (SAB) is based on differentiating complicated from uncomplicated disease. While this approach allows clinicians and investigators to group SAB patients into broadly similar clinical categories, it fails to account for the intrinsic heterogeneity of SAB. This is due in part to the fact that risk factors for metastatic infection and confirmed metastatic infection are considered as equivalent in most scoring systems. In this viewpoint, we propose a two-step system of categorizing patients with SAB. Initially, patients with SAB would be categorized as 'high risk' or 'low risk' for metastatic infection based upon an initial set of diagnostic procedures. In the second step, patients identified as 'high-risk' would undergo additional diagnostic evaluation. The results of this stepwise diagnostic evaluation would define a 'final clinical diagnosis' to inform an individualized final treatment plan.

Thoracic aortic vascular graft infection: outcome after conservative treatment without graft removal.

OBJECTIVES: Surgical debridement with aortic graft removal is considered the preferred treatment for thoracic aortic vascular graft infection (VGI). Conservative treatment with antibiotics only is usually reserved for inoperable patients. Due to Outpatient Parenteral Antimicrobial Therapy (OPAT) and better understanding of the antibiotic impact on biofilms, long-term targeted antibiotic therapy without graft removal may be an alternative treatment option for selected thoracic aortic VGI patients. The aim of this case series was to evaluate the outcome in patients with thoracic aortic VGI who were treated without graft removal. METHODS: This single-centre retrospective cohort study evaluated patients with a thoracic aortic VGI diagnosed between 2008 and 2021 and who were treated without graft removal. The primary outcome parameter was the 6-month mortality rate after VGI diagnosis. Secondary outcome parameters were cure rates and relapse of infection. RESULTS: Twenty-four patients with thoracic aortic VGI who were managed without graft removal were identified. The mortality rate 6 months after VGI diagnosis was 8% (2/24); one of these deaths was infection related. The median antibiotic treatment duration was 13 months (interquartile range 15). A total of 16 patients (67%) were cured. No relapses occurred after a median of 24-month (interquartile range 32) follow-up. CONCLUSIONS: Intensive antibiotic treatment, without graft removal, may be a non-inferior option in patients with a thoracic aortic VGI who are not considered for surgery.

Outcome in Patients after Autologous Femoral Vein Reconstruction for Primary Aortic Infection and Aortic Graft Infection: A Case Series.

BACKGROUND: For surgical treatment of primary aortic infection and aortic graft infection, in situ reconstruction with autologous vein(s) has the lowest rates of re-infection and of graft thrombosis. In this study, we have assessed the outcome after autologous femoral vein reconstruction in patients with aortic (graft) infection and we provide insights into the specific technical surgical considerations of the procedure. METHODS: In this retrospective single-center study, all patients who underwent autologous femoral vein reconstruction because of primary aortic infection or aortic graft infection between January 2012 and January 2020 were included. The primary outcome parameter was 30-day mortality. RESULTS: Twenty-nine patients with autologous femoral vein reconstruction for a primary aortic infection (n = 3) or aortic graft infection (n = 26) were included. An aorto-enteral fistula was detected in 13 patients (49%). Venous reconstruction of the aorta was performed with a single femoral vein in 17 patients (59%), and two femoral veins in 12 patients (41%). Thirty-day mortality was 17%. Relapse of infection occurred in two patients (7%) and no amputations were needed. One year after surgery, only three patients (10%) still needed stockings and after 2 years none of the patients used stockings. CONCLUSIONS: Central aortic reconstruction with femoral veins is a durable solution for primary aortic and aortoiliac graft infections with a low incidence of reinfections, amputations, and venous hypertension.

Individualizing the use of [18F]FDG-PET/CT in patients with complicated Staphylococcus aureus bacteremia: experiences from a tertiary care center.

PURPOSE: [18F]FDG-PET/CT scanning can help detect metastatic infectious foci and reduce mortality in patients with Staphylococcus aureus bacteremia (SAB), but it is unknown if patients with SAB and an indication for prolonged treatment because of possible endovascular, orthopaedic implant, or other metastatic infection still need [18F]FDG-PET/CT. METHODS: In a retrospective single-center cohort study, we included all consecutive adult patients with SAB between 2013 and 2020 if an [18F]FDG-PET/CT scan was performed and antibiotic treatment was planned for ≥ 6 weeks prior to [18F]FDG-PET/CT. We aimed to identify patients for whom treatment was adjusted due to the results of [18F]FDG-PET/CT, and assessed concordance of [18F]FDG-PET/CT and clinical diagnosis for infected prosthetic material. RESULTS: Among 132 patients included, the original treatment plan was changed after [18F]FDG-PET/CT in 22 patients (16.7%), in the majority (n = 20) due to diagnosing or rejecting endovascular (graft) infection. Antibiotic treatment modifications were shortening in 2, iv-oral switch in 3, extension in 13, and addition of rifampicin in 4 patients. Ninety additional metastatic foci based on [18F]FDG-PET/CT results were found in 69/132 patients (52.3%). [18F]FDG-PET/CT suggested vascular graft infection in 7/14 patients who lacked clinical signs of infection, but showed no infection of prosthetic joints or osteosynthesis material in eight patients who lacked clinical signs of such an infection. CONCLUSION: [18F]FDG-PET/CT can help refine treatment for SAB in patients with clinically suspected endovascular infection or vascular grafts, even if 6 weeks treatment is already indicated, but can be safely omitted in other patients who are clinically stable.

The diagnostic value of [18F]FDG-PET/CT in detecting septic thrombosis in patients with central venous catheter-related Staphylococcus aureus bacteremia.

PURPOSE: Septic thrombosis often complicates Staphylococcus aureus bacteremia (SAB) in patients with a central venous catheter. Currently there is no reference standard for diagnosis. We describe the diagnostic value of [18F]FDG-PET/CT imaging in a patient cohort and the potential contribution of quantitative measurements in detecting septic thrombosis. METHODS: We selected patients with catheter-related SAB from our institutional database (2013-2020). The contribution of [18F]FDG-PET/CT on clinical diagnosis of septic thrombosis was evaluated. Standardized Uptake Values (SUV) were measured and compared with a composite reference standard (clinical signs, initial [18F]FDG-PET/CT result, Multidisciplinary Team (MDT) meeting outcome) to identify a cut-off value for detecting septic thrombosis. RESULTS: We identified 93 patients with a catheter-related SAB. Quantitative measurements were possible for 43/56 patients in whom a [18F]FDG-PET/CT scan was performed. Septic thrombosis was clinically diagnosed in 30% (13/43) of the cases. In 85% of these cases, significant [18F]FDG-PET/CT uptake at the site of the thrombus was the deciding factor for diagnosis of septic thrombosis during the MDT meeting. All mean SUV's of thrombotic lesions were higher in patients with clinically proven septic thrombosis compared to patients in whom this diagnosis was rejected (p < 0.001). A SUVpeak thrombus/SUVmean blood ratio of 1.6 (AUC-ROC value 0.982) as cut-off to differentiate between septic thrombosis and non-septic thrombosis had a sensitivity of 92% (95% CI 64-100) and specificity of 89% (95% CI 65-99). An algorithm was designed to guide diagnosis of septic thrombosis. CONCLUSION: Quantitative [18F]FDG-PET/CT-derived parameters seem helpful to differentiate between septic and non-septic thrombosis in patients with catheter-related SAB.

Intravenous to Oral Switch in Complicated Staphylococcus aureus Bacteremia Without Endovascular Infection: A Retrospective Single-Center Cohort Study.

In this retrospective cohort study, selected patients with disseminated Staphylococcus aureus bacteremia, but without endovascular infection on echocardiography and 18F-FDG-PET/CT, were free of relapse after IV-oral switch. Mortality was low and similar to patients who received prolonged intravenous treatment. IV-oral switch was associated with a shorter length of hospital stay.

Dysregulated Innate and Adaptive Immune Responses Discriminate Disease Severity in COVID-19.

The clinical spectrum of COVID-19 varies and the differences in host response characterizing this variation have not been fully elucidated. COVID-19 disease severity correlates with an excessive proinflammatory immune response and profound lymphopenia. Inflammatory responses according to disease severity were explored by plasma cytokine measurements and proteomics analysis in 147 COVID-19 patients. Furthermore, peripheral blood mononuclear cell cytokine production assays and whole blood flow cytometry were performed. Results confirm a hyperinflammatory innate immune state, while highlighting hepatocyte growth factor and stem cell factor as potential biomarkers for disease severity. Clustering analysis revealed no specific inflammatory endotypes in COVID-19 patients. Functional assays revealed abrogated adaptive cytokine production (interferon-γ, interleukin-17, and interleukin-22) and prominent T-cell exhaustion in critically ill patients, whereas innate immune responses were intact or hyperresponsive. Collectively, this extensive analysis provides a comprehensive insight into the pathobiology of severe to critical COVID-19 and highlights potential biomarkers of disease severity.

Optimal use of [18F]FDG-PET/CT in patients with fever or inflammation of unknown origin.

BACKGROUND: [18F]FDG-PET/CT is one of the most important diagnostic techniques in the work-up of patients with fever of unknown origin (FUO)/inflammation of unknown origin (IUO). Little is known on how to optimize the diagnostic value of [18F]FDG-PET/CT in patients with FUO/IUO. METHODS: Retrospective study in all patients who underwent [18F]FDG-PET/CT during the work-up of FUO/IUO in a tertiary expert center between 2005 and 2014. Data were extracted from medical records. RESULTS: One hundred and four patients were identified, of whom 68 had a final diagnosis (65.4%). Mainly infections (30.8%) and non-infectious inflammatory diseases (30.8%). [18F]FDG-PET/CT contributed to the final diagnosis in 47 of the 68 patients (69.1%). In 21 patients [18F]FDG-PET/CT did not help making a diagnosis. In ten of these patients [18F]FDG-PET/CT was performed while body temperature, CRP and ESR were normal or unknown. Sixteen of 104 patients underwent repeated [18F]FDG-PET/CT. The second scan contributed to the final diagnosis in five of these patients. In two of these patients, the first scan retrospectively was truly non-contributory. In both patients the first [18F]FDG-PET/CT was made while CRP/ESR was low and fever was not present or not measured. A third or fourth scan never contributed to the final diagnosis when the second one did not. CONCLUSIONS: [18F]FDG-PET/CT contributed to the final diagnosis in 45.2% of patients, but never contributed when both inflammatory parameters and body temperature were normal. Repeating [18F]FDG-PET/CT should only be done in patients with a non-contributory [18F]FDG-PET/CT when new symptoms or signs appear, or when the first scan was made in absence of fever or elevated inflammatory parameters.

18F-FDG PET/CT-Guided Treatment Duration in Patients with High-Risk Staphylococcus Aureus Bacteremia: A Proof of Principle.

Current guidelines recommend intravenous antibiotic therapy for at least 4 wk in patients with high-risk Staphylococcus aureus bacteremia (SAB), because of the risk for metastatic infection. We evaluated the safety of a shorter duration of treatment in patients with high-risk SAB without signs of metastatic infection at presentation, using standard 18F-FDG PET/CT and echocardiography. Methods: Retrospective analyses were performed of patients with SAB admitted between 2013 and 2017 in 2 medical centers. Patients with risk factors for complicated bacteremia (community acquisition, persistently positive blood cultures, >72 h of fever, or foreign body materials present), a normal echocardiography result, and 18F-FDG PET/CT without signs of metastatic infection were included (cases) and compared with patients with uncomplicated bacteremia (absence of any of the risk factors and no known metastatic disease, controls). Primary outcomes were 3-mo SAB-specific mortality rate and recurrent infection. The secondary outcome was overall mortality. Results: We included 36 cases and 40 controls. Both groups had a similar treatment duration (15.9 vs. 15.4 d). No deaths occurred as a consequence of SAB in the cases, compared with 1 in the control group. One relapse occurred in the case group and 2 in the control group. Overall mortality did not differ between the groups (19.4% vs. 15.0%, P = 0.64). Conclusion: This study suggests that intravenous treatment for 2 wk in high-risk patients with SAB without endocarditis and absence of metastatic infection on 18F-FDG PET/CT is safe. A diagnostic-driven approach using 18F-FDG PET/CT to determine treatment duration in high-risk SAB seems feasible and allows tailoring treatment to individual patients.

18F-fluorodeoxyglucose positron-emission tomography combined with computed tomography as a diagnostic tool in native valve endocarditis.

OBJECTIVE: The aim of the study was to investigate the value of F-fluorodeoxyglucose positron-emission tomography combined with computed tomography (F-FDG-PET/CT) in diagnosing native valve endocarditis (NVE). PATIENTS AND METHODS: All patients with bacteremia and suspicion of NVE between January 2013 and June 2016 were identified from the hospitals' register and retrospectively included if echocardiography and F-FDG-PET/CT were performed within 14 days. F-FDG-PET/CT scans were scored independently by two nuclear medicine physicians. F-FDG-PET/CT was compared with the modified-Duke criteria and a multidisciplinary consensus. RESULTS: A total of 88 patients were included. In 10 patients with definite NVE according to the modified-Duke criteria, three (30.0%) patients had increased F-FDG uptake in or around the heart valves and seven (70.0%) patients had no increased F-FDG uptake. In patients without definite NVE according to the modified-Duke criteria, 89.7% (70/78) of the patients had no increased F-FDG uptake in or around the heart valves. Of all 20 patients with NVE according to multidisciplinary consensus, nine (45.0%) patients had increased F-FDG uptake in or around the heart valves and 11 (55.0%) patients had a normal F-FDG-PET/CT result. CONCLUSION: A negative F-FDG-PET/CT result should not be interpreted as an exclusion of NVE. In patients with possible or rejected NVE according to the modified-Duke criteria, F-FDG-PET/CT could be used in case of sustained suspicion of NVE owing to its high specificity in case of abnormal FDG uptake at the valve region. F-FDG-PET/CT is important for detecting metastatic infection which already warrants the need to perform F-FDG-PET/CT in all patients with suspected NVE.

Fever of Unknown Origin: the Value of FDG-PET/CT.

Fever of unknown origin (FUO) is commonly defined as fever higher than 38.3°C on several occasions during at least 3 weeks with uncertain diagnosis after a number of obligatory investigations. The differential diagnosis of FUO can be subdivided in four categories: infections, malignancies, noninfectious inflammatory diseases, and miscellaneous causes. In most cases of FUO, there is an uncommon presentation of a common disease. FDG-PET/CT is a sensitive diagnostic technique for the evaluation of FUO by facilitating anatomical localization of focally increased FDG uptake, thereby guiding further diagnostic tests to achieve a final diagnosis. FDG-PET/CT should become a routine procedure in the workup of FUO when diagnostic clues are absent. FDG-PET/CT appears to be a cost-effective routine imaging technique in FUO by avoiding unnecessary investigations and reducing the duration of hospitalization.

The diagnostic value of 18F-FDG-PET/CT and MRI in suspected vertebral osteomyelitis - a prospective study.

PURPOSE: The aim of this study was to determine the diagnostic value of 18F-fluorodeoxyglucose (FDG) positron emission tomography and computed tomography (PET/CT) and magnetic resonance imaging (MRI) in diagnosing vertebral osteomyelitis. METHODS: From November 2015 until December 2016, 32 patients with suspected vertebral osteomyelitis were prospectively included. All patients underwent both 18F-FDG-PET/CT and MRI within 48 h. All images were independently reevaluated by two radiologists and two nuclear medicine physicians who were blinded to each others' image interpretation. 18F-FDG-PET/CT and MRI were compared to the clinical diagnosis according to international guidelines. RESULTS: For 18F-FDG-PET/CT, sensitivity, specificity, PPV, and NPV in diagnosing vertebral osteomyelitis were 100%, 83.3%, 90.9%, and 100%, respectively. For MRI, sensitivity, specificity, PPV, and NPV were 100%, 91.7%, 95.2%, and 100%, respectively. MRI detected more epidural/spinal abscesses. An important advantage of 18F-FDG-PET/CT is the detection of metastatic infection (16 patients, 50.0%). CONCLUSION: 18F-FDG-PET/CT and MRI are both necessary techniques in diagnosing vertebral osteomyelitis. An important advantage of 18F-FDG-PET/CT is the visualization of metastatic infection, especially in patients with bacteremia. MRI is more sensitive in detection of small epidural abscesses.