Editor's Choice - Validation of the Management of Aortic Graft Infection Collaboration (MAGIC) Criteria for the Diagnosis of Vascular Graft/Endograft Infection: Results from the Prospective Vascular Graft Cohort Study.

OBJECTIVE: The timely management of vascular graft/endograft infection (VGEI) is crucial to a favourable outcome, yet can be challenging as there is no validated gold standard diagnostic test. Recently, a new case definition has been proposed by the Management of Aortic Graft Infection Collaboration (MAGIC) to close the diagnostic gap. The aim of this study was to validate the MAGIC criteria as a suggested diagnostic standard for the diagnosis of suspected VGEI in the prospective Vascular Graft Cohort study (VASGRA). METHODS: VASGRA is an open, prospective, observational cohort study. Prospective participants in VASGRA between 2013 and 2019 were included (257 patients; 137 with VGEI). The accuracy of the MAGIC criteria for a diagnosis of VGEI was evaluated retrospectively by calculating the sensitivity and specificity vs. the consensually adjudicated VASGRA infection status. RESULTS: The VASGRA cohort categorised 137 (53.3%) patients as "diseased" and 120 patients as "not diseased"; using the MAGIC criteria, 183/257 (71.2%) patients were considered to be "diseased". Thus, for the MAGIC criteria, a sensitivity of 99% (95% confidence interval [CI] 96-100) and a specificity of 61% (95% CI 52-70) were calculated. Considering suspected VGEI according to the MAGIC criteria as "not diseased" achieved congruent assessments of the VASGRA team and the MAGIC criteria, with a sensitivity of 93% and a specificity of 93%. The accuracy of the MAGIC criteria for the different graft locations were also compared. If the suspected VGEIs were assigned to the "not diseased" group, VGEIs of the thoracic aorta seemed to have a poorer sensitivity (86%; 95% CI 73-95) than the other graft locations. CONCLUSION: The current MAGIC criteria offer good sensitivity and specificity in the context of true infections but a reduced specificity for a possible VGEI.

Pre-clinical in vivo Models of Vascular Graft Coating in the Prevention of Vascular Graft Infection: A Systematic Review.

OBJECTIVE: Vascular graft infection (VGI) remains an important complication with a high mortality and morbidity rate. Currently, studies focusing on the role of vascular graft coatings in the prevention of VGI are scarce. Therefore, the aims of this study were to survey and summarise key features of pre-clinical in vivo models that have been used to investigate coating strategies to prevent VGI and to set up an ideal model that can be used in future preclinical research. DATA SOURCES: A systematic review was conducted in accordance with the Preferred reporting items for Systematic Reviews and Meta-Analysis guidelines. A comprehensive search was performed in MEDLINE (PubMed), Embase, and Web of Science. REVIEW METHODS: For each database, a specific search strategy was developed. Quality was assessed with the Toxicological data Reliability Assessment Tool (ToxRTool). The type of animal model, graft, coating, and pathogen were summarised. The outcome assessment in each study was evaluated. RESULTS: In total, 4 667 studies were identified, of which 94 papers focusing on in vivo testing were included. Staphylococcus aureus was the organism most used (n = 65; 67.7%). Most of the graft types were polyester grafts. Rifampicin was the most frequently used antibiotic coating (n = 43, 48.3%). In the outcome assessment, most studies mentioned colony forming unit count (n = 88; 91.7%) and clinical outcome (n = 72; 75%). According to the ToxRTool, 21 (22.3%, n = 21/94) studies were considered to be not reliable. CONCLUSION: Currently published in vivo models are very miscellaneous. More attention should be paid to the methodology of these pre-clinical reports when transferring novel graft coatings into clinical practice. Variables used in pre-clinical reports (bacterial strain, duration of activity coating) do not correspond well to current clinical studies. Based on the results of this review, a proposal for a complete and comprehensive set up for pre-clinical invivo testing of anti-infectious properties of vascular graft coatings was defined.

Management of Vascular Infections in Low- and Middle-Income Countries.

Background: Vascular infections are rare and challenging conditions with significant deaths and morbidity. Their management necessitates a multi-disciplinary approach and substantial human and financial resources. The management selected may be influenced by the available resources in low- and middle-income countries (LMICs), where such resources may be variable. Methods: We reviewed the published literature and reviewed the management options for various vascular infections with a focus on carotid, aortic, infrainguinal, and dialysis access infections. Results: Recommendations related to prevention and treatment will be offered from the perspective of LMICs. The general principles for prevention are in compliance with established surgical site infection guidelines and minimize the use of prosthetic material. Early detection and intervention by removing all infected prosthetic material, debridement, drainage, and coverage of the infected field with vascularized tissue are essential steps in the management of the infection. Revascularization using an extra-anatomic or in situ approach is individualized based on the resources and expertise available. Conclusions: The prevention and management of vascular infections in LMICs are effective by adhering to time-proven principles even with limited resources.

Aortobronchial fistula and Listeria endograft infection after repeated T/EVAR: a rare combination.

Here we present a rare combination of aortobronchial fistula and Listeria endograft infection after repeat endovascular aortic repair. Device retention, debridement and negative pressure wound therapy, in combination with suppressive antimicrobial therapy, led to satisfactory control of infection until the patient died due to another complication. The combination of an aortobronchial fistula and Listeria endograft infection has never been described before. This present case should encourage and show clinicians the importance of an interdisciplinary approach in highly difficult clinical courses.

Persistent Coxiella burnetii cardiovascular infection on Bentall-De Bono prosthesis.

Coxiella burnetii cardiovascular prosthetic infections are associated with high morbidity and mortality and represent a major health problem due to the lack of standardized management. We were confronted with a C. burnetii infection on Bentall-De Bono prosthesis characterized by a history of vascular infection with relapse that prompted us to screen for cases of C. burnetii on Bentall-De Bono vascular prosthesis monitored in our center. We screened patients between 1991 and 2019, from the French national reference center for Q fever. A microbiological criterion in addition to a lesional criterion was necessary to diagnose C. burnetii persistent vascular infection. Two thousand five hundred and eighty two patient were diagnosed with Coxiella burnetii infection and 160 patients with persistent C. burnetii vascular infection prosthesis, 95 of whom had a vascular prosthesis, including 12 with Bentall-De Bono prosthesis. Among patients with persistent C. burnetii prosthetic vascular infection, patients with Bentall-De Bono prostheses were significantly more prone to develop complications such as aneurysm, fistula, and abscess (62 versus 32%, two-sided Chi-square test, p = 0.04). All but one patient were treated with doxycycline and hydroxychloroquine for a mean (± standard deviation) period of 29.4 ± 13.6 months. Among the 12 patients, 5 had cardio-vascular complications, and 5 had prolonged antibiotherapy with doxycycline and hydroxychloroquine. Patients with C. burnetii vascular infection on Bentall-De Bono tend to be at high risk of developing complications (fistula, aneurysm, abscess, death). Surgery is rarely performed. Clinical, serological, and PET scanner imaging follow-up is recommended.

Mesenchymal stem cells have significant anti-infective effect on methicillin-resistant Staphylococcus epidermidis vascular graft infections.

OBJECTIVES: This study aims to evaluate the effects of mesenchymal stem cell (MSC) implantation on vascular graft infections caused by methicillin-resistant Staphylococcus epidermidis (MRSE) and compare with antibiotic treatment. MATERIALS AND METHODS: Healthy adult 56 Wistar rats (age, over 5 months; weighing, 300-350 g) were divided into eight groups. Group 1 was defined as the control group and group 2 was defined as the infected control group. Groups 3 and 4 were defined as Dacron grafted and MRSE infected groups, treated with tigecycline and MSCs, respectively. Groups 5 and 6 were performed polytetrafluoroethylene (PTFE) graft and infected with MRSE. These groups were also administered tigecycline and MSC treatment, respectively. Groups 7 and 8 were infected with MRSE without graft administration and were also performed tigecycline and MSC treatment, respectively. Grafts and soft tissue specimens were collected at 13 days postoperatively. Colony counts of peri-graft tissue were performed. All samples were evaluated by enzyme-linked immunosorbent assay (ELISA) for the markers that determine stem cell activity. RESULTS: The overall success of the treatments was assessed by the number of rats with MRSE recurrence, regardless of graft used. The difference between the untreated group 2, tigecycline groups (3, 5 and 7) and MSCs groups (4, 6 and 8) were statistically significant. Success of MSC and tigecycline treatments was similar in Dacron, PTFE, and non-grafted groups. There was a resistance of MRSE infection in Dacron groups to MSC and tigecycline treatments. This was considered to be indicative of the susceptibility of the Dacron grafts to infection. However, there was no significant difference between group 2 and Dacron groups in terms of bacterial colonization. ELISA results were significant in three cytokines. CONCLUSION: Mesenchymal stem cells can be considered as an alternative treatment option on its own or part of a combination therapy for control of vascular graft infections.

Management of abdominal aortic prosthetic graft and endograft infections. A multidisciplinary update.

Abdominal aortic graft infections (AGIs) occur in 1-5% of aortic prosthetic placements. It can result in limb amputation, pseudo-aneurysm formation, septic emboli, aorto-enteric fistulae, septic shock and death. The most frequently involved pathogens are methicillin-susceptible Staphylococcus aureus, methicillin-resistant Staphylococcus aureus and coagulase-negative staphylococci, followed by Enterobacteriaceae and uncommon bacteria. In case of gut involvement the presence of fungi has to be considered. Computed tomography angiography is actually the gold standard diagnostic imaging but magnetic resonance is a valid alternative. Nuclear medicine imaging is commonly used to improve sensitivity and specificity. Signs and symptoms are often aspecific and blood cultures can be negative, requiring alternative ways to detect the microorganism responsible for infection, such as 16S rRNA gene sequencing and molecular rapid diagnostic tests. Curative surgical intervention is the first choice approach, with in-situ reconstruction providing by far the best outcome and xenopericardial bovine patch as a promising option. For patients unable to undergo major surgery, the outcome of conservative approach remains uncertain but usually provides for life-long suppressive therapy. However, in selected cases an attempt of stopping antibiotic treatment after 3-6 months can be done. Given the difficulty in their management, we performed a review of AGIs, in order to raise awareness on clinical presentation, current available diagnostic tools, prophylaxis, surgical and anti-infective treatment of AGIs.

Efficacy of Antiseptic Solutions in Treatment of Staphylococcus Aureus Infected Surgical Wounds with Patches of Vascular Graft: An Experimental Study in Rats.

Background and objectives: Treatment of a prosthetic vascular graft infection (PVGI) remains a challenging problem in vascular surgery. The aim of this study was to design a novel rat model for treatment of peripheral vascular prosthesis infection caused by Staphylococcus aureus (S. aureus) and to determine the efficacy of different antiseptic solutions in suppressing or eradicating infection from the wound and the graft material itself. Materials and methods: A piece of Dacron vascular prosthesis was surgically implanted at the dorsum of 48 Wistar rats and the wounds were infected with 5 McFarland standard inoculum of S. aureus. Suppurating wounds were daily irrigated with different antiseptic solutions: octenidine dihydrochloride, povidone-iodine, chlorhexidine digluconate, and sterile saline. The antimicrobial action of antiseptics was defined according to their capability to eradicate bacteria from the graft surroundings and bacteriological examination of the graft itself. Extended studies on wound microbiology, cytology, and histopathology were performed with an additional group of 10 rats, treated with the most effective antiseptic-octenidine dihydrochloride. Results: Four-day treatment course with octenidine, povidone-iodine, and chlorhexidine resulted in 99.98% (p = 0.0005), 90.73% (p = 0.002), and 65.97% (p = 0.004) decrease in S. aureus colonies in wound washouts, respectively. The number of S. aureus colonies increased insignificantly by 19.72% (p = 0.765) in control group. Seven-day treatment course with octenidine eradicated viable bacteria from nine out of 10 wound washouts and sterilized one vascular graft. Conclusions: A reproducible rat model of PVGI with a thriving S. aureus infection was designed. It is a first PVGI animal model where different antiseptic solutions were applied as daily irrigations to treat peripheral PVGI. Seven-day treatment with octenidine eradicated bacteria from the wound washouts for 90% of rats and one vascular graft. Further studies are needed to investigate if irrigations with octenidine could properly cure vascular bed from infection to assure a successful implantation of a new synthetic vascular substitute.

Comparing diagnostic accuracy of 18F-FDG-PET/CT, contrast enhanced CT and combined imaging in patients with suspected vascular graft infections.

BACKGROUND: To evaluate the diagnostic accuracy of positron emission tomography/computed tomography with 18F-fluorodeoxyglucose (PET/CT), contrast-enhanced CT (CE-CT), and a combined imaging approach (CE-PET/CT) in patients with suspected vascular graft infection (VGI). METHODS: PET/CT and CE-CT were performed prospectively in 23 patients with suspected VGI. Diagnostic accuracy for PET/CT was assessed by using previously suggested cut-off points for maximum standardized uptake values (SUVmax) measured in the vicinity of the graft. Using a new 4-point scale for visual grading, two readers independently assessed the diagnostic accuracy for CE-CT and combined CE-PET/CT. Microbiological culture, obtained after open biopsy or graft explantation, and clinical follow-up of the patients served as the standard of reference. RESULTS: Sensitivity, specificity, negative predictive value (NPV), positive predictive value (PPV), and accuracy of PET/CT for the diagnosis of VGI was 100%, 50%, 100%, 72.2%, and 78.3%, using the most favorable SUVmax cut-off ≥ 4.9. Respective values for CE-CT were 100%, 50%, 100%, 72.2%, and 78.3% for reader 1, and 92.3%, 80%, 88.9%, 85.7%, and 86.9% for reader 2; while respective values for combined CE-PET/CT were 100%, 70%, 100%, 81.3%, and 86.9% for reader 1, and 100%, 80%, 100%, 86.7%, and 91.3% for reader 2. Additionally, imaging provided a conclusive clinical diagnosis in patients without graft infection (i.e., other sites of infection): five of ten patients with CE-CT, six of ten patients with PET/CT, and seven of ten patients with combined CE-PET/CT. CONCLUSION: The diagnostic accuracy of combined CE-PET/CT in patients with suspected VGI is very high. The combination of the high sensitivity of PET/CT in detecting metabolically active foci in infection, and the high specificity of CE-CT in detecting anatomic alterations, appears to be the reason why combined imaging outperforms stand-alone imaging in diagnosing VGI and may be supportive in future decision-making of difficult cases of suspected VGI. Clinical Trials.gov Identifier: NCT01821664.

A 57-Year-Old Man With Subacute Progressive Hemoptysis and Fevers.

CASE PRESENTATION: A 57-year-old man was admitted for 1 month of accelerating hemoptysis and hematemesis. Two weeks earlier, he first presented with fevers and hemoptysis of 2 weeks' duration and was diagnosed with community-acquired pneumonia treated with 5 days of ceftriaxone and azithromycin. He improved and was discharged, but his hemoptysis recurred 1 day after discharge and progressed over 9 days, leading to the present admission. He endorsed an 5-kg weight loss, daily fevers up to 39.4°C, and night sweats since discharge. His medical history was significant for peptic ulcer disease complicated by a perforated gastric ulcer 30 years ago, type 2 diabetes, and Barrett esophagus with recent normal upper endoscopy. The patient had coarctation of the aorta repaired 35 years ago. The patient takes aspirin, atorvastatin, and pantoprazole. He emigrated from Mexico 10 years before presentation and lives in Texas with his family. He returns to Mexico several times per year, most recently 2 days before admission. He works at a supermarket. He does not smoke, drink, or use illicit drugs. He denied sick contacts, pets, or incarceration.

Live intramacrophagic Staphylococcus aureus as a potential cause of antibiotic therapy failure: observations in an in vivo mouse model of prosthetic vascular material infections.

Objectives: To evaluate the significant role played by biofilms during prosthetic vascular material infections (PVMIs). Methods: We developed an in vivo mouse model of Staphylococcus aureus PVMI allowing its direct observation by confocal microscopy to describe: (i) the structure of biofilms developed on Dacron® vascular material; (ii) the localization and effect of antibiotics on these biostructures; and (iii) the interaction between bacteria and host tissues and cells during PVMI. Results: In this model we demonstrated that the biofilm structures are correlated to the activity of antibiotics. Furthermore, live S. aureus bacteria were visualized inside the macrophages present at the biofilm sites, which is significant as antibiotics do not penetrate these immune cells. Conclusions: This intracellular situation may explain the limited effect of antibiotics and also why PVMIs can relapse after antibiotic therapy.

The Results of In Situ Prosthetic Graft Replacement for Infected Aortic Disease.

BACKGROUND: Infected aortic disease is a serious clinical condition associated with significant morbidity and mortality. This study reviewed the outcomes of in situ aortic replacement with a prosthetic graft for infected aortic disease, including primary infected abdominal aortic aneurysms (PIAAA), infected aortic prosthetic grafts (IAPG), and infected aortic stent grafts (IASG). METHODS: Twenty-eight consecutive patients who underwent in situ aortic replacement with a prosthetic graft for PIAAA, IAPG, and IASG at a single center from January 2001 to December 2015 were retrospectively analyzed. Demographics, clinical characteristics, medical management, surgical procedure, and clinical outcomes were included. RESULTS: Nineteen patients with a PIAAA, three with an IAPG following open repair of abdominal aortic aneurysm (AAA), and six with an IASG following endovascular aortic repair underwent in situ prosthetic graft replacement with infected tissue and graft removal. In-hospital mortality was 7.1% (2/28). One died of bleeding on postoperative day 12, and the other died of hepatic failure on postoperative day 32. Of six patients with an IASG, two had major complications that were related to barb injury at the proximal aorta. The reinfection rate was 14.3% (4 of 28) during a mean follow-up of 35.7 months (1-142 months). All new grafts of three patients with IAPG were reinfected. The other patient became reinfected after surgery for PIAAA with iatrogenic small bowel perforation that was not detected during surgery. CONCLUSIONS: In situ graft replacement of PIAAA and IASG is feasible with acceptable outcomes, but the outcome for IAPG is questionable.

Long-term results confirmed that 18F-FDG-PET/CT was an excellent diagnostic modality for early detection of vascular grafts infection.

BACKGROUND: We sought to evaluate the potential role of positron emission tomography-computed tomography (PET-CT) for the detection and diagnosis of potential infections of vascular grafts using combining metabolic (i.e., radioactive fluorine-fluoro-D-deoxyglucose [18F-FDG]) PET with morphological (CT) information and investigate long-term capability. METHODS: Seventeen patients with suspected vascular-graft infection underwent thoracic-abdominal-pelvic FDG PET combined with contrast-enhanced CT using a hybrid PET-CT scanner providing co-registered PET and CT images. RESULTS: In this retrospect study, we suspected graft infection in 14 of 17 patients detected using PET-CT and increased the maximal uptake of 18F-FDG around the grafts. Other vascular localizations were not observed. All patients with positive PET-CT results underwent redo-surgery, and the infection was ultimately confirmed using microbiological testing in 12 of 14 patients. Follow-up time was median of 58 months (range 36-73 months) for all 17 patients. In these patients, there was no further evidence of graft infection found on clinical and imaging follow-up. CONCLUSIONS: This is first investigation presenting long-term follow-up, which confirmed that 18F-FDG-PET/CT is an excellent diagnostic modality for suspected vascular graft infection. 18F-FDG PET-CT exhibited a sensitivity of 100% and specificity of 71.4% for the detection of vascular-graft infection.

Aortofemoral Reconstruction for an Infected Graft Using Thrombosed Femoral Veins.

INTRODUCTION: Treatment of an infected aortic prosthesis is difficult and the ideal graft material is subject to debate. REPORT: A case of infected aortic prosthesis treated using bilateral thrombosed superficial femoral veins (SFVs) is presented. Bilateral reversed SFVs were cut longitudinally at both proximal ends about 3-4 cm and were sutured side by side. The operating time was 5 h. No sign of recurrent infection was observed when the patient suffered a myocardial infarction and died 6 months post-operatively. DISCUSSION: Thrombosed SFVs may be considered as a therapeutic option for infected aortic graft replacement.

Infective endocarditis in the setting of renal transplantation: Case report and review of the literature.

The potent immunosuppressive drugs used by transplant recipients place them at risk of infections. Data on infective endocarditis (IE) in the setting of renal transplantation (RT) are sparse. We describe a 36-year-old woman referred to a tertiary medical center for evaluation of elevated creatinine levels 1 month after a second RT. Work-up revealed the presence of all four of Duke's criteria: fever, persistent bacteremia, new-onset tricuspid regurgitation, and masses suspected to be vegetation attached to the tricuspid annulus. Symptoms resolved with antibiotic treatment and fluids. Fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) revealed hypermetabolic absorption in the femoral vascular graft that had been used for hemodialysis prior to transplantation. The graft was removed by open surgery, and the patient was discharged home in good condition with continued antibiotic treatment. Review of the literature yielded 73 previously reported cases of IE in renal transplant recipients. Several differences were noted from IE in the general population: lower male predominance, younger age (<60 years), absence in most cases of a preexisting structural cardiac anomaly, and more variable causative pathogens. Our case also highlights the importance of FDG-PET/CT for detecting the source of IE and alerts clinicians to the sometimes unexpected course of the disease in renal transplant recipients.

In Vivo Paracoccidioides sp. Biofilm on Vascular Prosthesis.

Paracoccidioidomycosis is an endemic mycosis caused by Paracoccidioides species limited to Latin America arising with the chronic form in 90% of cases. The capacity of microorganisms to form biofilms is considered of great importance medical since can contribute to the persistence and to the chronic state of the diseases. The ability of Paracoccidioides to form biofilm has been demonstrated in vitro. In our study, for the first time we have observed this capability in vivo on a vascular prosthesis using scanning electron microscope showing a dense network of Paracoccidioides yeasts covered by an extracellular matrix.

Type IIIb Endoleak Associated With an Infected Thoracoabdominal Endograft.

We present a 63-year-old male patient who presented with vague abdominal pain after an endoluminal thoracoabdominal aneurysm repair. He was found to have an infected endograft and an associated type IIIb endoleak. We believe that the infection contributed to the fabric degradation along the endograft and resulted in an expanding endoleak. Graft explantation was not performed because of the patient's multiple comorbidities, and the endoleak was treated with an additional stent graft and suppressive antibiotics. Endograft infection may lead to endograft degradation and associated leak. Therefore, an infectious etiology, although rare, should be considered when evaluating a delayed type IIIb endoleak.