Vascular Graft Infections, Mycotic Aneurysms, and Endovascular Infections: A Scientific Statement From the American Heart Association

Use of a Silver-Impregnated Vascular Graft: Single-Center Experience

INTRODUCTION

Vascular graft infection is a life threatening situation with significant morbidity and mortality. Bacterial graft infection can lead to false aneurysms, bleeding and sepsis. There are a lot of risky situations where grafts can become infected. It is therefore highly desirable to have a vascular graft that is resistant to infection. In this retrospective clinical study, a silver-impregnated vascular graft was evaluated in various indications.

METHODS

Our study included a total of 71 patients who received a silver-impregnated vascular graft during the period from 2013 to 2018. Patients had an aortoiliac localization of vascular graft in 61 cases (86%), and a peripheral localization on the lower limbs in 10 cases (14%). Indications for the use of these special vascular grafts were trophic lesions or gangrene in the lower limbs in 24 cases (34%), suspicious mycotic abdominal aortic aneurysm (mAAA) in 4 cases (5.5%), salmonela aortitis or aneurysms in 4 cases (5.5%), infection of the previous vascular graft in 11 cases (15.5%), other infections in 12 cases (17%), AAA rupture in 10 cases (14%) and other reasons (pre-transplant condition, multiple trauma, graft-enteric fistula) in 6 cases (8.5%). Thirty-day mortality, morbidity, the need for reintervention and amputation, primary and secondary graft patency, and finally the presence of a proven vascular graft infection were evaluated.

RESULTS

The 30-day mortality was 19.7%, and morbidity was 42.2%. The primary patency of the vascular graft was 91.5%. Reoperation was necessary in 10 cases (14%) and amputation was necessary in 10 cases (14%). The median length of hospital stay was 13 days and the mean follow-up period was 48 ± 9 months. During the follow-up period, six patients (8.5%) died from reasons unrelated to surgery or without any relation to the vascular graft. Secondary patency after one year was 88%. Infection of the silver graft was observed in three patients (4.2%).

CONCLUSIONS

Based on our results, the silver graft is a very suitable alternative for solving infectious, or potentially infectious, situations in vascular surgery. In particular, in urgent or acute cases, a silver graft is often the only option.

A Narrative Review of Experimental Models to Study Vascular Grafts Infections

Background

Many experimental models have been developed to decipher the mechanisms of vascular graft and endograft infections (VGEIs), and to elaborate strategies to prevent or treat their occurrence. A systematic literature research was conducted to identify the most accurate models for studying VGEIs, depending on the research question.

Methods

A narrative literature search was conducted using the MEDLINE and Cochrane databases, with no set limit on the date of publication, up to 10 August 2021. Ex vivo, in vitro, and in vivo animal studies on VGEIs, published in English or French, were selected. Cross references retrieved from selected articles on PubMed database were also included. Data on microorganisms and grafts studied, details of experimental models, and of graft implantation and removal in animal studies were collected.

Results

A total of 243 studies were included in the review after reading the full length articles: 55 in vitro studies, 169 animal studies, 17 studies which used both in vitro and animal models, and two ex vivo studies. Many differences in model characteristics were seen. The main in vitro model was the incubation of a graft sample in a bacterial solution, used to study the first steps of infection. In animals, vascular large animal models (dogs and pigs) were the most commonly described but supplanted over time by extravascular and particularly subcutaneous mouse and rat models, which have been reported increasingly over the last few years. In animal models, antibiotic prophylaxis and therapy were rarely administered (27.4% and 19.9%, respectively), and vascular reconstruction after VGEIs even less frequently (9.8%).

Conclusion

Despite protocol discrepancies, it was possible to dinstinguish three main experimental models (i.e., in vitro and in vivo vascular models, and extravascular models), which all remain of interest to study specific phases of VGEIs.

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Experimental models of vascular (endo)graft infections (VGEIs) can be split into in vitro, extravascular, and vascular ones.

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Each of these three groups can help answer specific questions on VGEIs.

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To improve reproducibility, future experimental studies require standardisation.

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Experimental studies should reproduce real life conditions as accurately as possible.

Femoral artery aneurysm with large hematoma from Pasteurella: case report and literature review

Background

Pasteurella multocida is a well-known gram-negative facultative anaerobe well known for its ability to cause soft tissue infections following animal bite or scratch. Here we present a case with mycotic aneurysm of the superficial femoral artery due to P. multocida infection.

Case presentation

A 62 year old male patient presented with worsening right leg pain and swelling. On examination, he was found to have profound swelling and erythema of the right medial thigh and tenderness to palpation. Computerized tomography showed findings suggestive of right femoral pseudoaneurysm with a large right medial thigh hematoma. Blood cultures grew P. multocida. Patient underwent emergent open resection of the mycotic aneurysm and vascular bypass surgery. Intraoperatively, the site was noted to be grossly infected with multiple pockets of pus which were drained and pus cultures grew P. multocida. The diagnosis of P. multocida bacteremia with right femoral mycotic aneurysm and thigh abscess was made. Patient received 6 weeks of intravenous ceftriaxone and recovered.

Conclusion

Our case is the first report on infection of peripheral vessel with Pasteurella and highlights the importance of prompt surgical intervention and effective antibiotic treatment

Mycotic aortic and left iliac ruptured aneurysm due to Escherichia Coli: a case report and literature overview

Mycotic aneurysm is a life-threatening disease often caused by Salmonella, Staphylococci and Streptococci species. Interestingly, Escherichia Coli (E. Coli) is described as a rare causative agent. We report the case of a patient who developed a mycotic aortic and ruptured left iliac aneurysm due to E. Coli. The patient developed a secondary aortic graft infection due to a mesenteric ischemia with fecal peritonitis. A literature overview of the current knowledge on mycotic aortic aneurysms specifically due to E. Coli is discussed including the clinical characteristics of patients, the management of the disease and the post-operative outcomes.

Long-term prognosis following vascular graft infection: a 10-year cohort study

Background

Vascular graft infection (VGI) remains a severe disease with high mortality and relapse rates. We performed a retrospective single-center cohort study to highlight factors associated with long-term all-cause mortality in patients with vascular graft infection.

Methods

All patients hospitalized in our facility over 10 years for VGI were included. VGI was defined by the presence of a vascular graft or an aortic stent graft (stent or fabric), associated with 2 criteria among clinical, biological, imaging, or microbiological elements in favor of VGI. The primary outcome was all-cause mortality. Empirical antibiotic therapy was considered as appropriate when all involved pathogens were susceptible in vitro to the antibiotics used. The surgical strategy was defined as nonoptimal when the graft was not removed in a late-onset surgery (>3 months) or no surgery was performed.

Results

One hundred forty-six patients were included. Empirical antibiotic therapy was administered in 98 (67%) patients and considered appropriate in 55 (56%) patients. Surgery was performed in 136 patients (96%) and considered as optimal in 106 (73%) patients. In multivariable analysis, appropriate empirical antibiotic therapy was associated with a lower probability of mortality (hazard ratio, 0.47 [95% confidence interval, .30–.79]; P = .002). Long-term survival did not differ according to whether the surgical strategy was considered optimal or not (log-rank = 0.66).

Conclusions

Appropriate empirical antibiotic therapy is a cornerstone of the management of VGI. Whenever possible, antibiotics must be associated with optimal surgical management. However, surgery could potentially be avoided in comorbid patients who are treated with appropriate antibiotics.

Vascular Graft Infections: An Overview of Novel Treatments Using Nanoparticles and Nanofibers

Vascular disease in elderly patients is a growing health concern, with an estimated prevalence of 15–20% in patients above 70 years old. Current treatment for vascular diseases requires the use of a vascular graft (VG) to revascularize lower or upper extremities, create dialysis access, treat aortic aneurysms, and repair dissection. However, postoperative infection is a major complication associated with the use of these VG, often necessitating several operations to achieve complete or partial graft excision, vascular coverage, and extra-anatomical revascularization. There is also a high risk of morbidity, mortality, and limb loss. Therefore, it is important to develop a method to prevent or reduce the incidence of these infections. Numerous studies have investigated the efficacy of antibiotic- and antiseptic-impregnated grafts. In comparison to these traditional methods of creating antimicrobial grafts, nanotechnology enables researchers to design more efficient VG. Nanofibers and nanoparticles have a greater surface area compared to bulk materials, allowing for more efficient encapsulation of antibiotics and better control over their temporo-spatial release. The disruptive potential of nanofibers and nanoparticles is exceptional, and they could pave the way for a new generation of prosthetic VG. This review aims to discuss how nanotechnology is shaping the future of cardiovascular-related infection management.

Stent infection and pseudoaneurysm formation after carotid artery stent treated by excision and in situ reconstruction with polytetrafluoroethylene graft: A case report

Background:

Stent infection after carotid artery stenting (CAS) can be a life-threatening postoperative complication, but there is a paucity of data due to its exceedingly low frequency. We report a case of stent infection with pseudoaneurysm formation after CAS that was treated through replacing the infected stent and pseudoaneurysm with a polytetrafluoroethylene (PTFE) synthetic vessel graft.

Case Description:

An 86-year-old man was treated for the right internal carotid artery with CAS in local hospital. One month after stenting, he suffered aspiration pneumonia and septicemia. Three months after stenting, swelling and tenderness of the right side of his neck appeared. His general condition deteriorated due to septicemia and he was unable to ingest anything by mouth as a result of decreasing levels of consciousness. He was transferred to our hospital. Computed tomography and digital subtraction angiography showed the presence of a pseudoaneurysm around the stent. The neck mass enlarged daily and surgical intervention was required to prevent closure of the airway. Stent and pseudoaneurysm resection and in situ reconstruction with a PTFE synthetic vessel graft were performed. The patient returned to his local hospital 36 days after surgery and had a modified Rankin Score of 5.

Conclusion:

Although the risk of reinfection is high due to the nature of artificial material, stent/pseudoaneurysm resection and in situ reconstruction with a PTFE synthetic vessel graft might be one of the best options for patients suffering stent infection after CAS. To the best of our knowledge, this is the first report of treatment using this material.

Primary infectious aortic aneurysm: a case series and review of the literature

Abstract Infectious aneurysms, formerly known as mycotic aneurysms, are rare, most often involve the aorta in young patients, and have a greater tendency to rupture than aneurysms of other etiologies. The most characteristic shape is saccular and the most common etiologic agents are Staphylococcus sp. and Salmonella sp. There is scant and imprecise information in the literature about correct nomenclature, diagnosis, and treatment. The authors present three cases in which diagnostic and therapeutic procedures were documented. In addition to reporting this case series, the authors also present a review of the subject, outlining pertinent diagnostic and therapeutic strategies.

Aneurisma infeccioso primário da aorta: série de casos e revisão da literatura

Infectious aneurysms, formerly known as mycotic aneurysms, are rare, most often involve the aorta in young patients, and have a greater tendency to rupture than aneurysms of other etiologies. The most characteristic shape is saccular and the most common etiologic agents are Staphylococcus sp. and Salmonella sp. There is scant and imprecise information in the literature about correct nomenclature, diagnosis, and treatment. The authors present three cases in which diagnostic and therapeutic procedures were documented. In addition to reporting this case series, the authors also present a review of the subject, outlining pertinent diagnostic and therapeutic strategies.

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

OBJECTIVE

Vascular graft infection (VGI) is a feared complication. Prevention is of the utmost importance and vascular graft coatings (VGCs) could offer a potential to do this, with in vitro research a first crucial step. The aim of this study was to summarise key features of in vitro models investigating coating strategies to prevent VGI in order to provide guidance for the setup of future translational research.

DATA SOURCES

A comprehensive search was performed in MEDLINE, Embase, and Web of Science.

METHODS

A systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. For each database, a specific search strategy was developed. Quality was assessed with the Toxicological data Reliability Assessment Tool (ToxRTool). In vitro models using a VGC and inoculation of the graft with a pathogen were included. The type of graft, coating, and pathogen were summarised. The outcome assessment in each study was evaluated.

RESULTS

In total, 4 667 studies were identified, of which 45 papers met the inclusion criteria. The majority used polyester grafts (68.2%). Thirty-one studies (68.9%) included antibiotics, and nine studies (20%) used a commercial silver graft in their protocol. New antibacterial strategies (e.g., proteolytic enzymes) were investigated. A variety of testing methods was found and focused mainly on bacterial adherence, coating adherence and dilution, biofilm formation, and cytotoxicity. Ninety-three per cent of the studies (n = 41) were considered unreliable.

CONCLUSION

Polyester is the preferred type of graft to coat on. The majority of coating studies are based on antibiotics; however, new coating strategies (e.g., antibiofilm coating) are coming. Many in vitro setups are available. In vitro studies have great potential, they can limit the use, but cannot replace in vivo studies completely. This paper can be used as a guidance document for future in vitro research.

Stapled Porcine Pericardium Displays Lower Infectivity In Vitro Than Native and Sutured Porcine Pericardium

BACKGROUND

Biological xenografts using tubulized porcine pericardium are an alternative to replace infected prosthetic graft. We recently reported an innovative technique using a stapled porcine pericardial bioconduit for immediate vascular reconstruction in emergency. The objective of this study is to compare the growth and adherence to grafts of bacteria and yeast incubated with stapled porcine pericardium, sutured or naked pericardium.

MATERIAL AND METHODS

One square centimeter of porcine pericardial patches, with or without staples or sutures, was incubated with 10⁵ colony forming units of Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis, and Candida albicans for 1, 6, and 24 h. The medium was collected to quantify planktonic microorganisms, while grafts were sonicated to quantify adherent microorganisms. Dacron and Dacron Silver were analyzed in parallel as synthetic reference prostheses.

RESULTS

Stapled porcine pericardium reduced the growth and the adherence of E coli (2- to 30-fold; P < 0.0005), S aureus (11- to 1000-fold; P < 0.0006), S epidermidis (>500-fold; P < 0.0001), and C albicans (12- to 50-fold; P < 0.0001) when compared to medium alone (growth) and pericardium or Dacron (adherence). Native and sutured porcine pericardium interfered with the growth and the adherence of E coli and C albicans, and Dacron with that of S epidermidis. As expected, Dacron Silver was robustly bactericidal.

CONCLUSIONS

Stapled porcine pericardium exhibited a lower susceptibility to infection by bacteria and yeasts in vitro when compared to the native and sutured porcine pericardium. Stapled porcine pericardium might be a good option for rapid vascular grafting without increasing infectivity.

OUTCOME IN PATIENTS AFTER AUTOLOGOUS FEMORAL VEIN RECONSTRUCTION FOR PRIMARY AORTIC INFECTION AND AORTIC GRAFT INFECTION: A CASE SERIES

OBJECTIVES

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 two 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.

Superior vena cava graft infection in thoracic surgery: a retrospective study of the French EPITHOR database

 

OBJECTIVES

To report our experience on the management of superior vena cava graft infection.

METHODS

Between 2001 and 2018, patients with superior vena cava synthetic graft or patch reconstruction after resection of intrathoracic tumours or benign disease were selected retrospectively from the French EPITHOR database and participating thoracic centres. Our study population includes patients with superior vena cava graft infection, defined according to the MAGIC consensus. Superior vena cava synthetic grafts in an empyema or mediastinitis were considered as infected.

RESULTS

Of 111 eligible patients, superior vena cava graft infection occurred in 12 (11.9%) patients with a polytetrafluoroethylene graft secondary to contiguous contamination. Management consisted of either conservative treatment with chest tube drainage and antibiotics (n = 3) or a surgical graft-sparing strategy (n = 9). Recurrence of infection appears in 6 patients. Graft removal was performed in 2 patients among the 5 reoperated patients. The operative mortality rate was 25%.

CONCLUSIONS

Superior vena cava graft infection may develop as a surgical site infection secondary to early mediastinitis or empyema. Graft removal is not always mandatory but should be considered in late or recurrent graft infection or in infections caused by aggressive microorganisms (virulent or multidrug resistant bacteria or fungi).

Contained Rupture of a Small Mycotic Abdominal Aneurysm in a Patient With Infective Endocarditis

A contained ruptured mycotic abdominal aneurysm is one of the complications of infective endocarditis. It is a complication that physicians should entertain when patients with infective endocarditis present with a complaint of back pain. This case report aims to increase the awareness of the possibility of a rupture of a small size abdominal mycotic aneurysm. This is a 36-year-old female with a history of intravenous (IV) drug use and infective endocarditis secondary to methicillin-sensitive Staphylococcus aureus presented with acute right-sided lower back pain. Work-up revealed a contained ruptured 2.5 cm mycotic abdominal aneurysm. She had an open surgical repair of the abdominal aorta followed by a mitral valve replacement a week later and she was discharged home on antibiotics and an anticoagulant. Untreated, a mycotic aneurysm can expand quickly and has a higher likelihood of rupturing as compared to an atherosclerotic abdominal aortic aneurysm. A contained ruptured mycotic abdominal aneurysm can lead to a dramatic hemodynamic compromise when it becomes uncontained, hence it is prudent that it is acted after it is diagnosed. Most authors recommend prompt surgery for all patients irrespective of the size of the aneurysm. Younger age is a factor to consider in choosing a repair approach despite the complications associated with both open surgical and endovascular repair.

Clinical Studies Reporting on Vascular Graft Coatings for the Prevention of Aortic Graft Infection: A Systematic Review and Meta-Analysis

OBJECTIVE

The aim of this study was to investigate the efficacy of vascular graft coatings used in the aortic position to prevent vascular graft infection (VGI).

METHODS

A systematic review was conducted in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines using a pre-registered protocol (CRD42020206436). Eligible studies used a vascular graft coating in the aortic position and reported on VGI. A search was performed in MEDLINE (PubMed), Embase, Web of Science, and the Cochrane Library. Primary outcome parameters were VGI, patency, and mortality. Pooled estimates of VGI were calculated using odds ratio (OR) and 95% confidence intervals (CIs) wherever possible. Quality assessment was performed with the Newcastle-Ottawa Assessment Scale and the Revised Cochrane risk of bias tool for randomised trials.

RESULTS

In total, 6 873 papers were identified. Only eight studies were included. Six of eight studies (75%) reported on known antimicrobial coating strategies such as antibiotics (n = 3) and silver (n = 3). In the other two studies, polymer coated grafts were used. Only three of eight studies compared coated with uncoated grafts (two antibiotic and one silver). Two randomised controlled trials reported on the effect of rifampicin soaked (1 mg/mL) grafts and showed no significant effect in the early (2 months; OR 0.69, 95% CI 0.29 - 1.62) or late (2 years; OR 0.73, 95% CI 0.23 - 2.32) post-operative periods. A retrospective cohort study focusing on the effect of silver coated grafts did not reveal any advantage (OR 0.19, 95% CI 0.02 - 1.64). Two polymer coated grafts were not considered to have a potential benefit in the prevention of VGIs.

CONCLUSION

Clinical studies reporting on the antibacterial effect of vascular graft coatings in the aortic position to prevent VGI are scarce. For silver and antibiotic coatings, no significant protection for VGI was observed. New types of grafts or long acting coating strategies are mandatory to prevent this complication in the future.

Successful management of infected right iliac pseudoaneurysm caused by penetration of migrated inferior vena cava filter: A case report

BACKGROUND

Indwelling inferior vena cava (IVC) filters might cause various complications, including filter penetration, filter fracture, filter migration, and thrombosis of the IVC. Penetration and migration complications are common, while a caudal migrated double-basket filter with associated infected iliac pseudoaneurysm has seldom been reported.

CASE SUMMARY

We report a 64-year-old female admitted for sudden onset of severe right abdominal pain after IVC filter placement for 3 mo. The patient had a history of failed endovascular IVC filter retrieval. Computed tomography showed that the retrieval hook of the filter penetrated the right common iliac artery and vein, leading to right iliac artery pseudoaneurysm accompanied by right ureteral obstruction with ipsilateral hydronephrosis, and bilateral iliac veins were occluded. Emergency open repair was performed to remove the IVC filter, the right iliac pseudoaneurysm, and the compromised segments of the iliac veins and IVC with right common iliac artery reconstruction. Staphylococcus aureus was isolated from the tissue culture. The patient was discharged on postoperative day 12 with anticoagulation therapy and antibiotic therapy after discharge. Six-month follow-up computed tomography revealed that the right common iliac artery was patent, and only mild hydronephrosis was detected.

CONCLUSION

An indwelling IVC filter, even ‘embedded’ within organized thrombus, could still cause life-threatening complications. Open procedures remain the last resort for IVC filters with severe complications.

Impact of PET/CT among patients with suspected mycotic aortic aneurysms

Purpose

To determine the impact of ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) on clinical management in patients with suspected mycotic aortic aneurysms (MAA).

Materials and methods

For this observational cohort study 101 PET/CT were acquired in 50 patients, thereof 50 for the initial diagnosis/baseline scan, 51 for follow-up. Impact on patient management was defined in three categories: PET/CT results were “confirmed” (by clinical follow-up), “suspected” (conclusive, not confirmed), or “misleading” (proven wrong by follow-up). For clinical follow-up patient data were recorded at the time of imaging, and at the latest recorded clinical visit. It included patient demographics, clinical information, laboratory data, results of microbiology and other diagnostic procedures, information about treatment, and patient’s general health condition.

Results

In four patients (8%) no clinical follow-up was feasible, the other 46 patients were clinically followed for a median of 898 days (IQR 320–4105). The combined evaluation of all 101 PET/CT demonstrated an impact on patient management in 78,5% of cases (48,5% confirmed, 30% suspected). Results of 21,5% of the PET/CT examinations were misleading. Respective values at baseline and at follow-up were: impact on patient management in 82% and 74,5% (70% and 27.5% confirmed, and 12% and 47% suspected), misleading cases in 18% and 25.5%.

Conclusion

In MAA, PET/CT has a high impact on patient management, which is more pronounced with baseline than with follow-up examinations. However, PET/CT results may be misleading in a smaller proportion of cases.

Ulnar infected pseudoaneurysm in the course of extended-spectrum beta-lactamase Escherichia coli septicemia

We describe the first case of proximal ulnar pseudoaneurysm due to extended-spectrum beta-lactamase-producing Escherichia coli. We performed an open ligation of the ulnar artery and partial excision of the aneurysmal sac. This article discusses the etiology and surgical management of ulnar-infected pseudoaneurysms according to the literature data.

Systematic Review and Meta-Analysis of Outcomes Following Endovascular and Open Repair for Infective Native Aortic Aneurysms

OBJECTIVE

The aim of our systematic review and meta-analysis was to demonstrate the clinical outcomes of open surgical repair (OSR) and endovascular aneurysm repair (EVAR) for infective native aortic aneurysms (INAAs).

METHODS

MEDLINE, Embase, and Cochrane Databases were searched for articles reporting OSR and/or EVAR repair of INAA. The methodological quality of included studies was assessed by the Newcastle-Ottawa scale and Moga-Score. Random-effects models were used to calculate the pooled measures.

RESULTS

A total of 34 studies were included, with 22 studies reporting OSR alone, 6 studies reporting EVAR alone and 6 comparative studies for INAAs. The pooled estimates of infection-related complications (IRCs) were 8.2% (95% CI 4.9%-12.2%) in OSR cohort and 23.2% (95% CI 16.1%-31.0%) in EVAR cohort. EVAR was associated with a significantly increased risk of IRCs compared with OSR during follow-up (OR 1.9, 95% CI 1.0-3.7). As for survival outcomes, the summary estimate rate of all cause 30-day, 3-month and 1-year mortality in OSR cohort were 11.7% (95% CI 7.7%-16.1%), 21.6% (95%CI 16.3%-27.4%) and 28.3% (95% CI 20.5%-36.7%; I²=50.47%), respectively. For EVAR cohort, the summary estimate rate of all cause 30-day, 3-month and 1-year mortality were 4.9% (95% CI 1.1%-10.4%), 9.4% (95% CI 2.7%-18.7%) and 22.2% (95% CI 12.4%-33.7%), respectively. EVAR was associated with a significantly decreased of 30-day mortality (OR 0.2, 95% CI 0.1-0.6). However, no difference was found between EVAR and OSR in 3-month (OR 0.2, 95% CI 0-1.1), 1-year all-cause mortality (OR 0.4, 95% CI 0.1-1.1) or aneurysm-related mortality (OR 1.4, 95% CI 0.5-3.9). Moreover, no difference of incidence of reintervention was observed (OR 2.6, 95% CI 0.9-7.7; I²=53.7%) between two groups.

CONCLUSIONS

EVAR could provide better short-term survival than OSR in patients with INAAs. However, patients undergoing EVAR suffered from higher risks of IRCs. EVAR could be considered as an alternative for low-risk patients with well-controlled infections or patients considered high-risk for open reconstruction.

Case report of the first cured patient with Mycobacterium Chimaera infection following cardiac valve replacement in the mainland of China

Background

Mycobacterium chimaera infections subsequent to cardiac surgery are related to contaminated heater-cooler devices, with high mortality. Nevertheless, few studies have been reported in Asia.

Case presentation

We described the case of a 55-year-old man with Mycobacterium chimaera infection following cardiac surgery in the mainland of China. He was diagnosed with endocarditis caused by Mycobacterium chimaera subsequent to open heart surgery. Metagenomic next-generation sequencing (mNGS) and 16S rRNA gene PCR analysis were used to identify potential pathogens. The patient underwent redo valve replacement surgery and received combination therapy with azithromycin, ethambutol, linezolid, and amikacin. No signs of relapse were observed during the 11-month follow-up visit.

Conclusions

This is the first documented case of Mycobacterium chimaera infection following cardiac surgery in the mainland of China and the first documented transnational imported case worldwide. Moreover, mNGS is a novel diagnostic technology that can guide antimicrobial therapy prior to obtaining fluid/tissue culture results for Mycobacterium chimaera, providing a new approach for the detection of potential Mycobacterium chimaera infection.

Fifteen-year, single-center experience with in situ reconstruction for infected native aortic aneurysms

OBJECTIVE

The purpose of the present study was to evaluate the survival and freedom from reinfection for patients with infected native aortic aneurysms (INAAs) treated with in situ revascularization (ISR), using either open surgical repair (OSR) or endovascular aneurysm repair (EVAR), and to identify the predictors of outcome.

METHODS

Patients with INAAs who had undergone ISR from January 2005 to December 2020 were included in the present retrospective single-center study. The diagnosis of INAAs required a combination of two or more of the following criteria: (1) clinical presentation, (2) laboratory results, (3) imaging findings, and (4) intraoperative findings. The primary endpoint was 30-day mortality. The secondary endpoints were in-hospital mortality, estimated survival, patency, and freedom from reinfection using the Kaplan-Meier method. The predictive factors for adverse outcomes were evaluated using the Mann-Whitney U test or the Fisher exact test and multivariate regression analysis.

RESULTS

A total of 65 patients (53 men [81.5%]; median age, 69.0 years; interquartile range, 61.5-75.0 years) were included, 31 (47.7%) were immunocompromised, 60 were symptomatic (92.3%), and 32 (49.2%) had presented with rupture, including 3 aortocaval fistulas (4.6%) and 12 aortoenteric fistulas (18.5%). The most common location was infrarenal (n = 39; 60.0%). Of the 65 patients, 55 (84.6%) had undergone primary OSR with ISR, 3 (4.6%) had required EVAR as a bridge to OSR, and 8 (12.3%) had undergone EVAR as definitive treatment. The approach was a midline laparotomy for 44 patients (67.7%), mostly followed by reconstruction and aortic-aortic bypass (n = 28; 40.6%) and the use of a silver and triclosan Dacron graft (n = 30; 43.5%). Causative organisms were identified in 55 patients (84.6%). The 30-day and in-hospital mortality rates were 6.2% (n = 4) and 10.8% (n = 7). The median follow-up was 33.5 months (interquartile range, 13.6-62.3 months). The estimated 1- and 5-year survival rates were 79.7% (95% confidence interval [CI], 67.6%-87.7%) and 67.4% (95% CI, 51.2%-79.3%). The corresponding freedom from reinfection rates were 92.5% (95% CI, 81.1%-97.1%) and 79.4% (95% CI, 59.1%-90.3%). On multivariate analysis, in-hospital mortality increased with uncontrolled sepsis (P < .0001), rapidly expanding aneurysms (P = .008), and fusiform aneurysms (P = .03). The incidence of reinfection increased with longer operating times (P = .009).

CONCLUSIONS

The selective use of ISR and OSR combined with targeted antimicrobial therapy functioned reasonably well in the treatment of INAAs, although larger, prospective, multicenter studies with appropriately powered comparative cohorts are necessary to confirm our findings and to determine the best vascular substitute and precise role of EVAR as a bridge to OSR or definitive treatment.

Infrarenal aortic reconstruction using autologous femoral vein for a mycotic aneurysm caused by Streptococcus equi

A common source of infection in equine, Streptococcus equi, is an uncommon pathogen in humans, rarely identified as the cause for mycotic aortic aneurysms. Typically associated with consumption of unpasteurized milk or contact with horses, S. equi can result in severe bacteremia, endocarditis and meningitis. We describe the presentation and successful management of a 69-year-old retired equestrian who underwent infrarenal aortic resection and reconstruction using autologous right femoral vein for a S. equi mycotic aneurysm.

The Microbiology of Infective Native Aortic Aneurysms in a Population-Based Setting

OBJECTIVE

The aim was to describe the microbiology of surgically treated infective native (mycotic) aortic aneurysms (INAAs), and associated survival and development of infection-related complications (IRCs).

METHODS

Data were pooled from 2 nationwide studies on surgically treated patients with INAAs in Sweden, between 1994 - 2016. Patients were grouped and analyzed according to culture results: 1) Staphylococcus aureus, 2) Streptococcus species (sp.), 3) Salmonella sp., 4) Enterococcus sp., 5) Gram-negative intestinal bacteria, 6) Other sp. (all other species found in culture), and 7) Negative cultures.

RESULTS

A sum of 182 patients were included, mean age 71 years (standard deviation; SD: 8.9). The median follow-up was 50.3 months (range 0 - 360). 128 (70.3%) patients had positive blood and/or tissue culture; Staphylococcus aureus n = 38 (20.9%), Streptococcus sp. n = 37 (20.3%), Salmonella sp. n = 19 (10.4%), Enterococcus sp. n = 16 (8.8%), Gram-negative intestinal bacteria n = 6, (3.3%), Other sp. n = 12 (6.6%) and Negative cultures n = 54 (29.7%). The estimated survival for the largest groups at 2-years after surgery was: Staphylococcus aureus 62% (95% Confidence interval 53.9 - 70.1), Streptococcus sp. 74.7% (67.4 - 82.0), Salmonella sp. 73.7% (63.6 - 83.8), Enterococcus sp. 61.9% (49.6 - 74.2), and Negative cultures 89.8% (85.5 - 94.1), P = .051. There were 37 IRCs (20.3%), and 19 (51.4%) were fatal, the frequency was insignificant between the groups. The majority of IRCs, 30/37 (81%), developed during the first postoperative year.

CONCLUSION

In this assessment of microbiological findings of INAAs in Sweden, 50% of the pathogens were Staphylococcus aureus, Streptococcus sp., or Salmonella sp.. The overall 20%-frequency of IRCs, and its association with high mortality, motivates long-term antibiotic treatment regardless of microbial findings.

[Prosthetic repair of the aorta with a cadaveric homograft for infection of bifurcated synthetic vascular prosthesis]

Infection of arterial vascular grafts is a rare but utterly severe complication in vascular surgery. Therapeutic policy in patients with graft infection has not been standardized, to be determined individually. One of the variants of surgical treatment is considered to be repeat aortic repair using a cadaveric graft. Presented in the article is a clinical case report concerning a 60-year-old male patient previously subjected to aortofemoral bifurcation bypass grafting with stage IV ischaemia of lower limbs according to the Pokrovsky-Fontaine classification. In the early postoperative period the events of critical ischaemia were not arrested. Due to the presence of a block of the femoropopliteal segment, as the second stage 3 days after the primary operation, the patient underwent autovenous femoropopliteal bypass grafting with a reversed autovein above the knee-joint fissure. The clinical course of critical ischaemia of the limb was relieved. During subsequent 8 months of follow up his state remained stable. Eight months after the primary operation he developed purulent discharge from the postoperative scar on the left femur. In the setting of the Purulent Surgery Department, the patient was emergently subjected to opening and drainage of the abscess of the postoperative scar. On the bottom of the wound there was a freely lying branch of a synthetic vascular prosthesis. Computed tomography revealed infection of the entire synthetic prosthesis and aneurysms of distal anastomoses. Given extremely high risk for the development of arrosive haemorrhage, a decision was made on operative treatment - repeat prosthetic repair of the abdominal aorta with a cadaveric allograft. At the Vascular Department of the Clinic of Faculty Surgery, laparotomy was performed, with removal of the infected graft, followed by debridement of the retroperitoneal space and repeat aortofemoral bifurcation prosthetic repair of the abdominal aorta with a cadaveric allograft. The wound healed with first intention. There was no evidence of infectious process relapse. The patient was discharged on postoperative day 15 in a satisfactory condition. The duration of follow up amounted to 6 months. The control examination showed that the pain-free walking distance was 500 m. Doppler ultrasonography demonstrated that the graft was functioning, with no signs of either anastomotic aneurysms or suppuration of the retroperitoneal space.

Mycotic aneurysm of the ascending aorta due to Escherichia coli: a case report

Ascending aorta mycotic aneurysm is a rare entity. It is a life-threatening condition because of the possibility of aortic dissection, or rupture. Escherichia coli is recognised as an uncommon cause of aortic mycotic aneurysm. An 81-year-old woman with a history of Escherichia coli pyelonephritis 4 months previously, was admitted to our centre for a mycotic aneurysm of the ascending aorta caused by Escherichia coli. She was successfully treated by urgent in situ replacement of the ascending aorta with a cryopreserved homograft, combined with antibiotics. Although infrequent, Escherichia coli mycotic aneurysm should be suspected in older patients with atherosclerosis and who developed septicaemia. Prompt treatment with a combination of appropriate antibiotics and surgery is required.

Contemporary Outcomes After Partial Resection of Infected Aortic Grafts

INTRODUCTION

Aortic graft infection remains a considerable clinical challenge, and it is unclear which variables are associated with adverse outcomes among patients undergoing partial resection.

METHODS

A retrospective, multi-institutional study of patients who underwent partial resection of infected aortic grafts from 2002 to 2014 was performed using a standard database. Baseline demographics, comorbidities, operative, and postoperative variables were recorded. The primary outcome was mortality. Descriptive statistics, Kaplan-Meier (KM) survival analysis, and Cox regression analysis were performed.

RESULTS

One hundred fourteen patients at 22 medical centers in 6 countries underwent partial resection of an infected aortic graft. Seventy percent were men with median age 70 years. Ninety-seven percent had a history of open aortic bypass graft: 88 (77%) patients had infected aortobifemoral bypass, 18 (16%) had infected aortobiiliac bypass, and 1 (0.8%) had an infected thoracic graft. Infection was diagnosed at a median 4.3 years post-implant. All patients underwent partial resection followed by either extra-anatomic (47%) or in situ (53%) vascular reconstruction. Median follow-up period was 17 months (IQR 1, 50 months). Thirty-day mortality was 17.5%. The KM-estimated median survival from time of partial resection was 3.6 years. There was no significant survival difference between those undergoing in situ reconstruction or extra-anatomic bypass (P = 0.6). During follow up, 72% of repairs remained patent and 11% of patients underwent major amputation. On univariate Cox regression analysis, Candida infection was associated with increased risk of mortality (HR 2.4; P = 0.01) as well as aortoenteric fistula (HR 1.9, P = 0.03). Resection of a single graft limb only to resection of abdominal (graft main body) infection was associated with decreased risk of mortality (HR 0.57, P = 0.04), as well as those with American Society of Anesthesiologists classification less than 3 (HR 0.35, P = 0.04). Multivariate analysis did not reveal any factors significantly associated with mortality. Persistent early infection was noted in 26% of patients within 30 days postoperatively, and 39% of patients were found to have any post-repair infection during the follow-up period. Two patients (1.8%) were found to have a late reinfection without early persistent postoperative infection. Patients with any post-repair infection were older (67 vs. 60 years, P = 0.01) and less likely to have patent repairs during follow up (59% vs. 32%, P = 0.01). Patients with aortoenteric fistula had a higher rate of any post-repair infection (63% vs. 29%, P < 0.01) CONCLUSION: This large multi-center study suggests that patients who have undergone partial resection of infected aortic grafts may be at high risk of death or post-repair infection, especially older patients with abdominal infection not isolated to a single graft limb, or with Candida infection or aortoenteric fistula. Late reinfection correlated strongly with early persistent postoperative infection, raising concern for occult retained infected graft material.

Under the Radar: A Case Report of a Missed Aortoenteric Fistula

Introduction

An aortoenteric fistula (AEF) is an abnormal connection between the aorta and the gastrointestinal tract that develops due to a pathologic cause. It is a rare, but life-threatening, cause of gastrointestinal (GI) bleeding. Although no single imaging modality exists that definitively diagnoses AEF, computed tomography angiography (CTA) of the abdomen and pelvis is the preferred initial test due to widespread availability and efficiency.

Case Report

Many deaths occur before the diagnosis is made or prior to surgical intervention. We describe a case of a patient with a history of aortic graft repair who presented with active GI bleeding.

Conclusion

Although CTA can make the diagnosis of AEF, it cannot adequately rule it out. In patients with significant GI bleeding and prior history of aortic surgery, vascular surgery should be consulted early on, even if CTA is equivocal.

The Japanese Clinical Practice Guidelines for Management of Sepsis and Septic Shock 2020 (J-SSCG 2020)

The Japanese Clinical Practice Guidelines for Management of Sepsis and Septic Shock 2020 (J-SSCG 2020), a Japanese-specific set of clinical practice guidelines for sepsis and septic shock created as revised from J-SSCG 2016 jointly by the Japanese Society of Intensive Care Medicine and the Japanese Association for Acute Medicine, was first released in September 2020 and published in February 2021. An English-language version of these guidelines was created based on the contents of the original Japanese-language version. The purpose of this guideline is to assist medical staff in making appropriate decisions to improve the prognosis of patients undergoing treatment for sepsis and septic shock. We aimed to provide high-quality guidelines that are easy to use and understand for specialists, general clinicians, and multidisciplinary medical professionals. J-SSCG 2016 took up new subjects that were not present in SSCG 2016 (e.g., ICU-acquired weakness [ICU-AW], post-intensive care syndrome [PICS], and body temperature management). The J-SSCG 2020 covered a total of 22 areas with four additional new areas (patient- and family-centered care, sepsis treatment system, neuro-intensive treatment, and stress ulcers). A total of 118 important clinical issues (clinical questions, CQs) were extracted regardless of the presence or absence of evidence. These CQs also include those that have been given particular focus within Japan. This is a large-scale guideline covering multiple fields; thus, in addition to the 25 committee members, we had the participation and support of a total of 226 members who are professionals (physicians, nurses, physiotherapists, clinical engineers, and pharmacists) and medical workers with a history of sepsis or critical illness. The GRADE method was adopted for making recommendations, and the modified Delphi method was used to determine recommendations by voting from all committee members.As a result, 79 GRADE-based recommendations, 5 Good Practice Statements (GPS), 18 expert consensuses, 27 answers to background questions (BQs), and summaries of definitions and diagnosis of sepsis were created as responses to 118 CQs. We also incorporated visual information for each CQ according to the time course of treatment, and we will also distribute this as an app. The J-SSCG 2020 is expected to be widely used as a useful bedside guideline in the field of sepsis treatment both in Japan and overseas involving multiple disciplines.

Abdominal aortic endograft infection. A decade of experience and literature review

INTRODUCTION

Aortic endograft infection is an infrequent but life-threatening complication after endovascular abdominal aortic repair (EVAR). There is no consensus on management of endograft infection and little evidence has been published in our country. Endograft explantation is considered the "gold standard" treatment whereas percutaneous or surgical perigraft and sac drainage associated to antibiotics should be considered and alternative therapy.

METHODS

We carried out a retrospective and descriptive review of abdominal aortic endograft infections at our tertiary center (Hospital Universitario Cruces) during last ten years (2010-2019).

RESULTS

We describe the clinical and microbiological characteristics of 10 EVAR infections, their management and outcomes. The incidence of graft infection after EVAR was 3%. The mean time to the clinical presentation of infection was 16.9 months (median 4.5 months). The microbiological diagnosis was reached in 100% of cases (predominance of gram-positive species). The overall mortality rate was 50% (although the survival rate was 100% after surgical drainage of the sac).

CONCLUSIONS

Perigraft or aneurysm sac aspiration culture shows their diagnostic utility as microbiological diagnosis was reached in all cases despite of blood cultures being only positive in 50% of the samples. Surgical drainage and endograft preservation combined with antibiotherapy show remarkable results. The high heterogeneity in our case series makes difficult to offer general recommendations, thus far, a tailored approach to treatment is suggested.

Citrobacter koseri Surgical Site Infection after Femoropopliteal Vein Bypass for Popliteal Artery Aneurysm Treated with a Graft Preserving Strategy

Background: A 69-year-old man underwent ligation and evacuation of a popliteal artery aneurysm with a femoral-to-popliteal vein bypass. He had a history of Citrobacter koseri prostatitis two months prior to the surgery. One month postoperatively, he presented with extremity swelling, redness, and fluid collections around the graft. Methods: A graft preserving strategy was adopted. The patient underwent operative drainage, washing, and received long-term antibiotic therapy. Fluid culture grew Citrobacter koseri, previously not reported as cause of surgical site infection with infrainguinal graft involvement. Results: The infection was treated successfully, and the patient is remains symptom free 18 months post-operatively. Conclusions: This case highlights the importance of considering culturing the aneurysm content in the presence of infectious history.

Subarachnoid hemorrhage secondary to Brucella-induced cerebral aneurysm: a case report

BACKGROUND

Brucellosis is a common zoonotic disease that is prevalent in many areas worldwide. This infectious disease can occasionally affect the central nervous system but intracranial arteries are rarely involved.

CASE PRESENTATION

A 17-year-old female who had a history of recurrent fever for 1 month was admitted for subarachnoid hemorrhage due to cerebral aneurysm rupture. Surgery was performed to fix the aneurysm, but the patient had persistent fever after the surgery. Cerebrospinal fluid testing showed a high white blood cell count and elevated protein level but no pathogen was identified in the first two tests. Brucella melitensis was identified in the third cerebrospinal fluid culture, and a diagnosis of brucellosis was finally rendered. The patient was subsequently treated with anti-Brucella medications and her symptoms improved significantly at the last follow-up.

CONCLUSION

Although extremely rare, Brucella-induced cerebral aneurysms can occur and this should be considered in the differential diagnosis of cerebrovascular accidents, especially in Brucella epidemic areas.

Aortic Fistulas: Pathophysiologic Features, Imaging Findings, and Diagnostic Pitfalls

Fistulas between the aorta and surrounding organs are extremely rare but can be fatal if they are not identified and treated promptly. Most of these fistulas are associated with a history of trauma or vascular intervention. However, spontaneous aortic fistulas (AoFs) can develop in patients with weakened vasculature, which can be due to advanced atherosclerotic disease, collagen-vascular disease, vasculitides, and/or hematogenous infections. The clinical features of AoFs are often nonspecific, with patients presenting with bleeding manifestations, back or abdominal pain, fever, and shock. Confirmation with invasive endoscopy is often impractical in the acute setting. Imaging plays an important role in the management of AoFs, and multiphasic multidetector CT angiography is the initial imaging examination of choice. Obvious signs of AoF include intravenous contrast material extravasation into the fistulizing hollow organ, tract visualization, and aortic graft migration into the adjacent structure. However, nonspecific indirect signs such as loss of fat planes and ectopic foci of gas are seen more commonly. These indirect signs can be confused with other entities such as infection and postoperative changes. Management may involve complex and staged surgical procedures, depending on the patient's clinical status, site of the fistula, presence of infection, and anticipated tissue friability. As endovascular interventions become more common, radiologists will need to have a high index of suspicion for this entity in patients who have a history of aneurysms, vascular repair, or trauma and present with bleeding. Online supplemental material and the slide presentation from the RSNA Annual Meeting are available for this article. ^©RSNA, 2021.

Prosthetic vascular graft infection: A systematic review and meta-analysis on diagnostic accuracy of 18FDG PET/CT

INTRODUCTION

There is a high risk of mortality and morbidity associated with Vascular Graft Infections (VGI) which requires early diagnosis. The aim of the present systematic review and meta-analysis was to evaluate the diagnostic accuracy, sensitivity and specificity of 18FDG PET/CT in diagnosing VGI.

METHODS

A systematic review was conducted according to the PRISMA guidelines through a search in Embase, PubMed, and Cochrane databases. We evaluated five parameters including specificity, sensitivity, negative and positive predictive values (NPV and PPV), and accuracy. We used STATA/MP 15.0 (StataCorp, College Station, TX) for all of our analyses.

RESULTS

Overall 10 studies including 320 patients undergone 18FDG PET/CT were included. The sensitivity, specificity, positive and negative likelihood ratios along with their 95% CI were 0.92 (95% CI 0.88-0.95), 0.76 (95% CI 0.76-0.70), 3.49 (95% CI 3.49-2.32) and 0.14 (95% CI 0.09-0.23), respectively. The diagnostic odds ratio (DOR) for diagnosis of VGI was 37.12 (95% CI 14.84-92.82). The mean cut-off value of the maximum standardized uptake value (SUVmax) for diagnosis of VGI was 5.39 while the overall mean SUVmax among patients with VGI was 8.47.

CONCLUSION

According to our results, 18FDG PET/CT is a useful diagnostic method in detecting active VGI with high diagnostic accuracy. Because of its ability to evaluate morphology and main texture using SUVmax, the 18FDG PET/CT provides an objective assessment of aspects and extent of disease activity, which results in preventing unnecessary surgery, proper treatment planning, and evaluating the effectiveness of treatment.

Cryopreservation moderates the thrombogenicity of arterial allografts during storage

INTRODUCTION

Management of vascular infections represents a major challenge in vascular surgery. The use of cryopreserved vascular allografts could be a feasible therapeutic option, but the optimal conditions for their production and use are not precisely defined.

AIMS

To evaluate the effects of cryopreservation and the duration of storage on the thrombogenicity of femoral artery allografts.

METHODS

In our prospective study, eleven multi-organ-donation-harvested human femoral arteries were examined at five time points during storage at -80°C: before cryopreservation as a fresh native sample and immediately, one, twelve and twenty-four weeks after the cryopreservation. Cross-sections of allografts were perfused with heparin-anticoagulated blood at shear-rates relevant to medium-sized arteries. The deposited platelets and fibrin were immunostained. The thrombogenicity of the intima, media and adventitia layers of the artery grafts was assessed quantitatively from the relative area covered by fibrin- and platelet-related fluorescent signal in the confocal micrographs.

RESULTS

Regression analysis of the fibrin and platelet coverage in the course of the 24-week storage excluded the possibility for increase in the graft thrombogenicity in the course of time and supported the hypothesis for a descending trend in fibrin generation and platelet deposition on the arterial wall. The fibrin deposition in the cryopreserved samples did not exceed the level detected in any of the three layers of the native graft. However, an early (up to week 12) shift above the native sample level was observed in the platelet adhesion to the media.

CONCLUSIONS

The hemostatic potential of cryopreserved arterial allografts was retained, whereas their thrombogenic potential declined during the 6-month storage. The only transient prothrombotic change was observed in the media layer, where the platelet deposition exceeded that of the fresh native grafts in the initial twelve weeks after cryopreservation, suggesting a potential clinical benefit from antiplatelet therapy in this time-window.

Infection, Infectious Agents and Vascular Disease

BACKGROUND

Infectious agents may be involved in the pathogenesis of vascular disease and related complications. The aim of this review is to analyze the most relevant information on the common infections related to vascular disease, discussing the main pathophysiological mechanisms.

METHODS

In the current review, the most important evidence on the issue of infections and vascular disease is searched on Medline, Scopus, and ScienceDirect database.

RESULTS

Among infectious agents, herpesviruses, parvovirus B19, hepatitis viruses, human immunodeficiency virus, severe acute respiratory syndrome coronavirus 2, treponema pallidum, mycobacterium tuberculosis, pseudomonas aeruginosa, staphylococcus aureus, and candida albicans seem to particularly related to vascular disease.

CONCLUSION

Infectious agents may affect vessel's homeostasis and functionality, both on the arterial and venous side, by means of several pathophysiological mechanisms such as dysregulation in vasomotor function, thromboembolic complications, initiation and progression of atherosclerosis, alteration of perivascular adipose tissue, recruiting inflammatory cells and molecules.

Limitations and Pitfalls of FDG-PET/CT in Infection and Inflammation

White blood cells activated by either a pathogen or as part of a systemic inflammatory disease are characterized by high energy consumption and are therefore taking up the glucose analogue PET tracer FDG avidly. It is therefore not surprising that a steadily growing body of research and clinical reports now supports the use of FDG PET/CT to diagnose a wide range of patients with non-oncological diseases. However, using FDG PET/CT in patients with infectious or inflammatory diseases has some limitations and potential pitfalls that are not necessarily as pronounced in oncology FDG PET/CT. Some of these limitations are of a general nature and related to the laborious acquisition of PET images in patients that are often acutely ill, whereas others are more disease-specific and related to the particular metabolism in some of the organs most commonly affected by infections or inflammatory disease. Both inflammatory and infectious diseases are characterized by a more diffuse and less pathognomonic pattern of FDG uptake than oncology FDG PET/CT and the affected organs also typically have some physiological FDG uptake. In addition, patients referred to PET/CT with suspected infection or inflammation are rarely treatment naïve and may have received varying doses of antibiotics, corticosteroids or other immune-modulating drugs at the time of their examination. Combined, this results in a higher rate of false positive FDG findings and also in some cases a lower sensitivity to detect active disease. In this review, we therefore discuss the limitations and pitfalls of FDG PET/CT to diagnose infections and inflammation taking these issues into consideration. Our review encompasses the most commonly encountered inflammatory and infectious diseases in head and neck, in the cardiovascular system, in the abdominal organs and in the musculoskeletal system. Finally, new developments in the field of PET/CT that may help overcome some of these limitations are briefly highlighted.

Impact of unknown incidental findings in PET/CT examinations of patients with proven or suspected vascular graft or endograft infections

Vascular graft or endograft Infections (VGEI) are rare but severe complications of vascular reconstructive surgery, and associated with significant mortality and morbidity risk. Positron emission tomography/computed tomography with ¹⁸F-fluorodeoxyglucose (PET/CT) has been shown to have a high diagnostic accuracy in the detection of VGEI. In this single-center prospective cohort study, we assessed the rate and the impact on patient management of relevant unknown incidental findings in PET/CT of patients with proven or suspected VGEI, and clinical follow-up of all patients was performed. Our study results show a comparably high rate of relevant unknown incidental findings (181 in 502 examinations), with documented direct impact on patient management in 80 of 181 (44%) of all findings. PET/CT scan- and patient-based evaluation revealed impact on patient management in 76 of 502 (17%) of all PET/CT scans, and in 59 of 162 (36%) of all patients, respectively. Furthermore, PET/CT correctly identified the final diagnosis in 20 of 36 (56%) patients without VGEI. In conclusion, in proven and suspected VGEI, PET/CT detects a high rate of relevant unknown incidental findings with high impact on patient management.

Concomitant paravisceral and thoracic mycotic aortic aneurysms in a cirrhotic patient

In the present case report, we have described concomitant, rapidly expanding, abdominal and thoracic mycotic aortic pseudoaneurysms in a patient who had originally presented for right arm superficial thrombophlebitis and a right-hand abscess in the presence of methicillin sensitive Staphylococcus aureus bacteremia. Within 12 days, the patient had developed a rapidly expanding paravisceral mycotic abdominal aortic pseudoaneurysm that required open surgical repair. After the initial operation, she developed a thoracic mycotic aortic aneurysm that ultimately required open surgical repair. Her postoperative course after the initial operation was complicated by decompensated hepatitis C cirrhosis that required convalescence before repair of the thoracic aneurysm. Follow-up data were available for ≤10 months after the initial operation.

Treatment and Outcomes of Aortic Graft Infections Using a Decision Algorithm

BACKGROUND

Aortic graft infection (AGI) is a rare but devastating complication requiring both explant of the infected prosthesis and lower extremity revascularization. Despite a variety of methods to treat AGI, there is a paucity of evidence that describes comparative outcomes. Moreover, controversy exists surrounding what the optimal repair strategy is with limited descriptions of how these techniques should be employed in this complex group of patients. Therefore, the purpose of this analysis was to review our experience with AGI management while highlighting a practice philosophy that can achieve acceptable outcomes.

METHODS

All AGI patients between 2002-2019 were reviewed. The primary end-point was 30-day mortality. Secondary end-points included complications, re-infection, unplanned re-operation and all-cause mortality. Kaplan-Meier methodology was used to estimate time to events. Cox regression models were employed to identify association between patient factors and operative strategy with survival. Subgroup analysis included outcome comparison among four different operative approaches(extra-anatomic bypass with aortic ligation [EAB] and in-situ reconstruction [ISR] using either NAIS, cryopreserved allograft [Cryo], or antibiotic-soaked prosthetic grafts [Other]).

RESULTS

142 patients (male-69%, mean age 67 ± 11 years) were reviewed. Median time to AGI presentation was 52 (IQR 16-128) months. ISR was performed in 70% (n = 99)[ISR: NAIS-49% (n = 49), Cryo, 33% (n = 33) and Other-23% (n = 23)]. EAB was used in 26% (n = 37), of which 57% (n = 21) were staged repairs[no reconstruction, 4%: intraoperative death-2, AGI removal without reconstruction-2]. A graft enteric erosion/fistula was identified in 39% (n = 55). Mean follow-up time was 14 ± 27 (median 2.2[IQR 0.1-16]) months. Overall, 30-day mortality was 21% and 69% (n = 98) experienced a complication. The most common complications were pulmonary (35%;n = 50), vascular (28%;n = 39), gastrointestinal (22%;n = 31) and renal (21%;n = 30). Freedom from re-infection at one and three years was 78 ± 5% and 73 ± 6% while freedom from unplanned re-operation was 50 ± 5% and 40 ± 6%, respectively. Corresponding one- and five-year freedom from all-cause mortality was 67 ± 4% and 53 ± 4%. When stratified by the four different repair strategies, unadjusted rates of postoperative complications and mortality were not different. However, EAB patients had more renal complications. All-cause mortality predictors included age (HR 1.04, 95%CI 1.01-1.1; P = 0.003), CHF (HR 2.7, 1.3-5.7; P = 0.01), and graft enteric erosion/fistula (HR 2.2, 1.3-3.8;P = 0.005) while total graft excision was protective (HR 0.34, 0.2-0.7; P = 0.003).

CONCLUSIONS

AGI repair, regardless of operative strategy, results in significant early morbidity, and mortality. The need for unplanned re-operation is common; however, long-term survival is acceptable in appropriately selected patients. Re-infection risk mandates life-long surveillance and consideration of indefinite anti-microbial suppression in certain subgroups. Due to the complexity and intensity of care, all AGI should be treated, when possible, at centers performing high-volume aortic surgery.

Risk of non-typhoidal Salmonella vascular infections is increased with degree of atherosclerosis and inflammation: A multicenter study in southern Taiwan

BACKGROUND

Atherosclerosis and vascular inflammatory response have been considered as risk factors for non-typhoidal Salmonella (NTS) vascular infection. The study aims to assess the risk of vascular infection by measuring atherosclerosis severity, NTS vascular infection (NTSVI) score, and serum levels of inflammatory markers in people with NTS bacteremia.

METHODS

A prospective observational study was conducted in two medical centers and two regional hospitals. Adults aged ≥50 years with NTS bacteremia who underwent computed tomography (CT) scan for revealing vascular infections were enrolled. The degree of atherosclerosis was scaled by a calcium score determined by a CT scan. Serum concentrations of inflammatory biomarkers were determined in the patients enrolled in a medical center.

RESULTS

Fourteen (20.3%) of 69 patients with NTS bacteremia had vascular infections. Calcium scores over the thoracic (12,540 vs. 3,261, P = 0.0005) and abdominal (9755 vs. 3,461, P = 0.0006) aorta of those with vascular infections were higher than those without vascular infection. All vascular infections were present in the high-risk group (NTSVI score ≥1), yielding a sensitivity of 100% and specificity of 30.9%. Among 17 low-risk patients (NTSVI score <1), none had vascular infections, resulting in a negative predictive value of 100%. Higher plasma concentrations of IL-1β were detected in the cases of vascular infection than those in the control group (23.6 vs. 1.06 pg/mL, P = 0.001).

CONCLUSION

Atherosclerosis of the aorta which is associated with a positive NTSVI score can predict the occurrence of vascular infections and serum IL-1β could be a biomarker for vascular infection in patients with NTS bacteremia.

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.

Midterm outcome of biosynthetic collagen prosthesis for treating aortic and peripheral prosthetic graft infections

OBJECTIVES

To report the midterm outcomes of treating prosthetic peripheral and aortic graft infections using a biosynthetic collagen prosthesis in a tertiary vascular center.

METHODS

A retrospective analysis of all patients with prosthetic peripheral and aortic graft infections who underwent in situ reconstruction using a biosynthetic collagen prosthesis between March 2015 and November 2020 was conducted. Perioperative and midterm outcomes were analyzed.

RESULTS

A biosynthetic collagen prosthesis was used in 19 patients (14 males, median age 66 years) to reconstruct the femoral artery (n = 6), iliac artery (n = 1), and infrarenal aorta (n = 12). All patients were treated for a prosthetic vascular graft infection. The median follow-up period was 26.6 months (range 1-66 months). The 30-day graft failure rate was 15.7% (n = 3), leading to a major amputation in one patient (5.3%). All grafts were occluded aortofemoral reconstructions in patients with occluded superficial femoral artery and were treated by immediate thrombectomy. The 30-day mortality rate was 5.3% (n = 1), and survival after 3 years was 63.2%. The reinfection rate was 5.3% (n = 1). At 13.6 months, the occlusion of a femoral graft was detected in 5.3% (n = 1) and was treated with a new interposition graft. We observed no graft rupture or degeneration during follow-up.

CONCLUSIONS

Although results of in situ repair with autologous vein seem to be superior with little or none reinfection and low number of occlusions, biosynthetic collagen prostheses show acceptable midterm outcomes in terms of graft occlusion and mortality after prosthetic peripheral and aortic graft infections. Similar to other xenogenous materials, the reinfection rate is low with this prosthesis. With regard to immediate availability and easy handling, the use of a biosynthetic collagen prosthesis might be favorable compared to other replacement materials while treating prosthetic graft infections.

Infected Aneurysm of the Native Aorta due to Coccidioides posadasii

Coccidioidomycosis is an endemic fungal infection that is typically asymptomatic or associated with pulmonary disease. Extrapulmonary disease may involve the skin, bones, or central nervous system, yet endovascular infections are exceedingly rare. We report the first case, to our knowledge, of coccidioidomycosis of the native aorta in an immunocompromised host.