In situ replacement of infected aortic grafts with rifampicin-bonded prostheses: the Leicester experience (1992 to 1998)

Revascularization and Digestive Tract Repair in Secondary Aortoenteric Fistula Using a Single-Center in Situ Revascularization Strategy

BACKGROUND

Information regarding optimal revascularization and digestive tract repair in secondary aortoenteric fistula (sAEF) remains unclear. Thus, reporting treatment outcomes and presenting comprehensive patient details through a structured treatment approach are necessary to establish a treatment strategy for this rare, complex, and fatal condition.

METHODS

We performed a single-center retrospective review of consecutive sAEF managed based on our in situ revascularization and intestinal repair strategy. The primary endpoint of this study was all-cause mortality, and secondary endpoints were the incidence of in-hospital complications and midterm reinfections.

RESULTS

Between 2007 and 2020, 16 patients with sAEF, including 13 men (81%), underwent in situ revascularization and digestive tract repair. The median follow-up duration for all participants was 36 (interquartile range, 6-62) months. Among the participants, 81% (n = 13), 13% (n = 2), and 6% (n = 1) underwent aortic reconstruction with rifampin-soaked grafts, unsoaked Dacron grafts, and femoral veins, respectively. The duodenum was the most commonly involved site in enteric pathology (88%; n = 14), and 57% (n = 8) of duodenal breaks were repaired by a simple closure. Duodenum's second part-jejunum anastomosis was performed in 43% of patients (n = 6), and 19% of the patients (n = 3) died perioperatively. In-hospital complications occurred in 88% patients (n = 14), and the most frequent complication was gastrointestinal. Finally, 81% patients (n = 13) were discharged home. Oral antibiotics were administered for a median duration of 5.7 months postoperatively; subsequently, the participants were followed up carefully. Reinfection was detected in 6% of the patients (n = 1) who underwent reoperation without any complications. The 1-year and 3-year overall survival rates of participants were 75% (n = 12) and 75% (n = 9), respectively, and no sAEF-related deaths occurred, except perioperative death.

CONCLUSIONS

Surgical intervention with contemporary management based on our vascular strategy and digestive tract procedure may be a durable treatment for sAEF.

Clinical outcome of graft removal versus preservation in abdominal aortic graft infection: a systematic review and meta-analysis

Purpose

The purpose of this study was to compare the clinical outcomes of abdominal aortic graft infection (AGI) treated with removal of the graft vs. graft preservation.

Methods

The electronic databases PubMed, Embase, and Cochrane Library for studies that reported on AGI were searched. Observational studies and case series of at least 10 cases that reporting on the prevalence, microbiology, and outcomes of AGI were included.

Results

Our search identified 23 studies that met our inclusion criteria, reporting on a total of 873 patients who underwent open surgical repair (OSR) or endovascular aneurysm repair (EVAR). Of these patients, 833 received graft removal, and 40 received graft preservation. The prevalence of AGI was reported to be 1.0% (95% confidence interval [CI], 0.5%-1.8%) after OSR and 0.4% (95% CI, 0%-1.1%) after EVAR. The pooled estimates of 1-year, 2-year, and 5-year mortality were 28.7% (95% CI, 19.4%-38.8%), 36.6% (95% CI, 24.6%-49.5%), and 51.8% (95% CI, 38.4%-65.1%) in the graft removal group and 16.1% (95% CI, 4.1%-32.2%), 18.5% (95% CI, 5.7%-35.1%), and 50.0% (95% CI, 31.6%-68.4%) in the graft preservation group. The 30-day mortality rate's risk ratio (RR) for graft removal vs. preservation was 0.98 (95% CI, 0.40-2.38), while the 1-year mortality rate's RR was 3.44 (95% CI, 1.60-7.42).

Conclusion

The 30-day mortality rate of AGI treatment was found to be high, whether using graft removal or preservation. In selected patients, implementing antibiotics with graft preservation as an initial management may be helpful in reducing the mortality rate.

Silver acetate and Triclosan Antimicrobial Graft Evaluation for surgical Repair of aortic disease (STAGER Study)

BACKGROUND

The aim of this study was to assess perioperative and late performance of a silver acetate and triclosan impregnated antimicrobial vascular graft (Intergard Synergy, Intervascular SAS, La Ciotat, France) during open surgical repair of abdominal aortic aneurysms (AAA), and to compare it with standard polyester grafts ones.

METHODS

This retrospective single-centre study (STAGER Study, clinicaltrials.gov: NCT04557254) included patients undergone non-infectious AAA surgical repair between 2012 and 2019, divided into two groups according to the implanted aortic prosthesis: standard polyester graft (PolyG) and silver-triclosan graft (SynG). Early primary endpoints were 30-day mortality, major adverse events (MAEs), and reintervention rates; late primary endpoints were overall and aortic-related survival, reintervention-free survival, and graft infection rate at a mean follow-up (FU) of 49.4±26.8 months.

RESULTS

Five hundred forty-seven patients were included [PolyG 49%, and SynG 51%]. Both groups were substantially homogeneous in risk factors and demographics. Two patients died within 30 days. In-hospital MAE rate [PolyG 14.2% vs. SynG 10.7%; P=.248] and 30-day reintervention rate were not significantly different [PolyG 2.6% vs. SynG 1.4%; P=.374]. At 5 years, overall survival in the PolyG and SynG groups were 85% and 84%, respectively. Reintervention-free survival was 82% for both groups. Aortic-related survival was 95% and 96%, respectively. Graft infection was observed in 8 (3.3%) PolyG patients and 5 (1.8%) SynG patients.

CONCLUSIONS

Silver acetate and triclosan impregnated grafts demonstrated good early and mid-term results, being considered safe and durable for AAA open repair. Similar graft infection and related death rates were observed compared to polyester standard grafts, supporting non-superiority of one graft over the other.

Reconstruction of primary and secondary aortic infections with an antimicrobial graft

INTRODUCTION

In situ reconstruction (ISR) with autologous veins is the preferred method in infectious native aortic aneurysms (INAAs) or vascular (endo)graft infection (VGEI). However, access to biological substitutes can prove difficult and lacks versatility. This study evaluates survival and freedom from reinfection after ISR of INAA/VGEI using the antimicrobial Intergard Synergy graft combining silver and triclosan.

METHODS

From February 2014 to April 2020, 86 antimicrobial grafts were implanted for aortic infection. The diagnosis of INAA/VGEI and reinfection was established based on the Management of Aortic Graft Infection Collaboration criteria. Survival was analyzed using the Kaplan-Meier method and log-rank P values.

RESULTS

The antimicrobial graft was implanted in 32 cases of INAA, 28 of VGI, and 26 of VEI. The median age was 69.0 (interquartile range: 62.0; 74.0), with a history of coronary artery disease (n = 21; 24.4%), chronic kidney disease (n = 11; 12.8%), cancer (n = 21; 24.4%), and immunosuppression (n = 27; 31.4%). Imaging showed infiltration (n = 14; 16.3%), air (n = 10; 11.6%), and rupture (n = 16; 18.6% including 22 aortoenteric fistulae [AEnF]). Symptoms included fever (n = 37; 43.0%), shock (n = 11; 12.8%), and pain (n = 47; 54.7%). Repair was undertaken through a midline laparotomy in 75 cases (87.2%) and coeliac cross-clamping in 19 (22.1%), suprarenal in 26 (30.2%), plus celiac trunk (n = 3), mesenteric (n = 5), renal (n = 13), or hypogastric (n = 4) artery reconstruction, and omental flap coverage (n = 41; 48.8%). For AEnF, the gastrointestinal tract was repaired using direct suture (n = 14; 16.3%) or resection anastomosis (n = 8; 9.3%). Causative organisms were identified in 74 patients (86.0%), with polymicrobial infection in 32 (37.2%) and fungal coinfection in 7 (8.1%). Thirty-day and in-hospital mortality were 14.0% and 22.1% (n = 12 and 19, respectively, 3 INAA [9.4%], 7 VGI [25.0%], and 9 VEI [34.6%]). Seventy patients (81.4%) had a postoperative complication, 44 (51.2%) of whom returned to the operative room. The 1- and 2-year survival rates were 74.0% (95% confidence interval [CI]: 63.3-82.1) and 69.8% (95% CI: 58.5-78.5), respectively. Survival was significantly better for INAA vs VGEI (P = .01) and worse for AEnF (P = .001). Freedom from reinfection was 97.2% (95% CI: 89.2-99.3) and 95.0% (95% CI: 84.8-98.4) with six reinfections (7.0%) requiring two radiological/six surgical drainage and two graft removals. Primary patency was 88.0% (95% CI: 78.1-93.6) and 79.9% (95% CI: 67.3-88.1) with no significant difference between INAA and VGEI (P = .16).

CONCLUSIONS

ISR of INAA or VGEI with the antimicrobial graft showed encouraging early mortality, comparable to the rates found in femoral vein (9%-16%) and arterial allograft (8%-28%) studies, as well as mid-term reinfection. The highest in-hospital mortality was noted for VEI including nearly 50% of AEnF.

Secondary Aorto-Colonic Fistula: A Case Report and Literature Review of a Rare Complication after EVAR

Background: Aorto-enteric fistula (AEF) is a rare but fatal condition. The incidence of the overall AEF was approximately 0.36–2%, but the incidence of the aorto-colonic fistula was scarcely reported. A history of abdominal pain, fever, or gastrointestinal bleeding (GIB) in a patient with a history of aortic intervention should be highly suspected of this condition. This report describes a patient with lower GIB after an endovascular aneurysm repair (EVAR) for a symptomatic abdominal aortic aneurysm (AAA). Case Presentation: A 65-year-old man with a history of EVAR for symptomatic AAA presented with a massive lower GIB for two weeks. He also had a history of left lower quadrant pain and low-grade fever. Diverticular disease was suspected, and medical treatment was administered. After the initial conservative treatment, a colonoscopy was performed. The findings showed a fistula that exposed an aortic stent graft at the left-sided colon. An aorto-colonic fistula was diagnosed. After administering intravenous (IV) antibiotics, a staged axillo-bifemoral bypass graft with aortic stent graft explantation was performed. The patient recovered well and was discharged home after a month of hospitalization and IV antibiotics. Conclusion: In a patient with a history of aortic intervention, any abdominal pain, unknown fever, or even GIB should be suspected of complications of aortic intervention. Highly suspicious of this rare condition is the key to an early diagnosis and prompt treatment.

Management and Clinical Outcome of Aortic Graft Infections: A Single-Center Retrospective Study

BACKGROUND

This study aimed to evaluate the outcome of various treatment options for aortic graft infection (AGI) patients and identify factors affecting their prognosis.

METHODS

The data of AGI patients from January 2008 to December 2019 were retrospectively collected and analyzed. The primary endpoints were 30-day mortality and perioperative complication-related morbidity; the secondary endpoints were re-infection (RI) rates, primary and secondary graft patency, overall mortality, duration of antibiotic therapy, and the number of antibiotic types used in treatment.

RESULTS

There was no significant difference in the 30-day mortality and perioperative-related complications between the conservative treatment, in-situ reconstruction (ISR), and extra-anatomic reconstruction (EAR) groups. The ISR group had lower re-infection rates and better overall survival rates than the EAR and conservative treatment groups. Different bypass graft conduits had no significant influence on the RI rate or primary and secondary graft patency. AGI patients infected with high-virulence pathogens had higher RI and overall mortality rates than those infected with low virulence pathogens, but this was not statistically significant. Initial procedures prior to the AGI also had no influence on the prognosis of AGI patients. Patients undergoing ISR or EAR surgery received antibiotic therapy for a longer duration than patients undergoing conservative treatment. Patients without RI received more types of antibiotics than patients with RI.

CONCLUSIONS

ISR had lower RI rates and better overall survival rates than EAR and conservative treatment and may be a better choice for patients with AGI. Several factors were found to have no influence on patients' prognosis however, further studies are required.

Treatment of vascular graft infections: gentamicin-coated ePTFE grafts reveals strong antibacterial properties in vitro

Vascular graft infections (VGI) are severe complications in prosthetic vascular surgery with an incidence ranging from 1 to 6%. In these cases, synthetic grafts are commonly used in combination with antimicrobial agents. Expanded polytetrafluoroethylene (ePTFE) is in clinical use as a synthetic graft material and shows promising results by influencing bacterial adhesion. However, the literature on antibiotic-bound ePTFE grafts is scarce. Gentamicin is a frequently used antibiotic for local treatment of surgical site infections, but has not been evaluated as antimicrobial agent on ePTFE grafts. In this study, we examine the antimicrobial efficacy and biocompatibility of novel types of gentamicin-coated ePTFE grafts in vitro. ePTFE grafts coated with gentamicin salt formulations with covalently-bound palmitate were evaluated in two drug concentrations (GP1.75% and GP3.5%). To investigate effects from types of formulations, also suspensions of gentamicin in palmitate as well as polylactide were used at comparable levels (GS + PA and GS + R203). Antibacterial efficacies were estimated by employing a zone of inhibition, growth inhibition and bacterial adhesion assay against Staphylococcus aureus (SA). Cytotoxicity was determined with murine fibroblasts according to the ISO standard 10993-5. Gentamicin-coated ePTFE grafts show low bacterial adherence and strong antibacterial properties in vitro against SA. Bactericidal inhibition lasted until day 11. Highest biocompatibility was achieved using gentamicin palmitate GP1.75% coated ePTFE grafts. ePTFE grafts with gentamicin-coating are effective in vitro against SA growth and adherence. Most promising results regarding antimicrobial properties and biocompatibility were shown with chemically bounded gentamicin palmitate GP1.75% coatings. Graphical abstract.

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.

Mycotic aortic aneurysm in a debilitated patient with compromised immunity; beware of Candida!

Candida is a rare cause of infected aortic aneurysms. We report the case of a diabetic patient with end stage kidney disease who underwent repair of a leaking abdominal aortic aneurysm. He was on long-term antibiotic treatment for malignant otitis externa. Candida albicans was isolated from the culture of the excised aneurysm wall. An infected aortic aneurysm due to Candida has not been previously reported in a patient with malignant otitis externa. This case report aims to highlight that Candida should be suspected as a cause of infected aortic aneurysms in patients with debilitation and chronic immunosuppression. Management of such cases can be extremely challenging, especially in resource-poor settings, and we will be touching upon the advantages and disadvantages of various treatment options.

Rupture of a dissecting thoracoabdominal aortic aneurysm due to Citrobacter freundii infection

We describe a case of an elderly man with Citrobacter freundii-associated infectious rupture of a dissecting thoracoabdominal aortic aneurysm. We performed an emergency thoracoabdominal aortic replacement using a rifampicin-soaked prosthetic graft and omental flap wrapping. The patient was discharged on postoperative day 255, although he experienced pseudomembranous enteritis and paraplegia.

Results of cryopreserved arterial allograft replacement for thoracic and thoracoabdominal aortic infections

BACKGROUND

Primary and secondary thoracic aortic infections are rare but associated with high morbidity and mortality. There is currently no consensus on their optimal treatment. Arterial allografts have been shown to be resistant to bacterial colonization. Complete excision of infected material, especially synthetic grafts, combined with in situ aortic repair is considered the best treatment of abdominal aortic infections. The aim of this study was to assess the management of thoracic and thoracoabdominal aortic infections using arterial allografts.

METHODS

Between January 2009 and December 2017, all patients with thoracic and thoracoabdominal aortic native or graft infections underwent complete excision of infected material and in situ arterial allografting. The end points were the early mortality and morbidity rates and early and late rates of reinfection, graft degeneration, and graft-related morbidity.

RESULTS

Thirty-five patients with a mean age of 65.6 ± 9.2 years were included. Twenty-one (60%) cases experienced graft infections and 14 (40%) experienced native aortic infections. Eight (22.8%) patients had visceral fistulas: 5 (14.4%) prosthetic-esophageal, 1 (2.8%) prosthetic-bronchial, 1 (2.8%) prosthetic-duodenal, and 1 (2.8%) native aortobronchial. In 12 (34.3%) cases, only the descending thoracic aorta was involved; in 23 (65.7%) cases, the thoracoabdominal aorta was involved. Fifteen (42.8%) patients died during the first month or before discharge: 5 of hemorrhage, 4 of multiorgan failure, 3 of ischemic colitis, 2 of pneumonia, and 1 of anastomotic disruption. Eleven (31.5%) patients required early revision surgery: 6 (17.1%) for nongraft-related hemorrhage, 3 (8.6%) for colectomy, 1 (2.9%) for proximal anastomotic disruption, and 1 (2.9%) for tamponade. One (2.9%) patient who died before discharge experienced paraplegia. One (2.9%) patient experienced stroke. Six (17.1%) patients required postoperative dialysis. Among them, four died before discharge. The mean length of stay in the intensive care unit was 11 ± 10.5 days; the mean length of hospital stay was 32 ± 14 days. During a mean follow-up of 32.3 ± 23.7 months, three allograft-related complications occurred in survivors (15% of late survivors): one proximal and one distal false aneurysm with no evidence of reinfection and one allograft-enteric fistula. The 1-year and 2-year survival rates were 49.3% and 42.5%, respectively.

CONCLUSIONS

Although rare, aortic infections are highly challenging. Surgical management includes complete excision of infected tissues or grafts. Allografts offer a promising solution to aortic graft infection because they appear to resist reinfection; however, the grafts must be observed indefinitely because of the risk of late graft complications.

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.

Novel prefabricated bovine pericardial grafts as alternate conduit for septic aortoiliac reconstruction

OBJECTIVE

Infection of prosthetic aortic grafts represents a serious complication with high morbidity and mortality. Replacement with autologous material is recommended; however, in its absence, biological material should be favored. In the present retrospective cohort study, we evaluated the short- and midterm results with the use of commercially available prefabricated bovine pericardium grafts (BPGs) used for the management of aortic graft infection or aortic reconstructive surgery in the presence of systemic infection.

METHODS

We performed a retrospective analysis of patients in whom BPGs had been used for aortic reconstruction at two vascular centers. Prefabricated vascular pericardium grafts were preferred over other biological reconstruction techniques for selected cases. Comorbidities, procedure-related details, perioperative morbidity, clinical outcomes, and mortality were analyzed.

RESULTS

From 2014 to 2019, 21 patients had received BPGs at two Austrian vascular centers. Their median age was 63 years (interquartile range [IQR], 55-71 years), the patients were predominantly male (76%), and the median body mass index was 25.3 kg/m² (IQR, 21.7-27.3 kg/m²). The major comorbidities included arterial hypertension, peripheral artery disease, smoking, and chronic pulmonary disease. The indications for surgery were vascular graft or endograft infection in 62% and aortic reconstruction in the presence of systemic infection in 38%. Three patients (14%) had aortoenteric fistulas. Surgery was technically successful in all cases. The median follow-up was 21.6 months (IQR, 6.0-34.6 months). The 30-day mortality was 9.5%. The 1- and 2-year overall survival was 84% and 75%, respectively. Of the 21 patients, 89% had remained free of recurrent infection. One of the two reinfections had resolved after treatment of the underlying focus. At 2 years, the primary and assisted primary patency rates were 86% and 94%, respectively. No limbs were lost during follow-up.

CONCLUSIONS

Prefabricated BPGs represent a promising alternative for the management of aortic graft infections and aortoiliac reconstruction in the presence of systemic infection.

Efficacy of antiseptic impregnation of aortic endografts with rifampicin compared to silver against in vitro contamination with four bacteria that frequently cause vascular graft infections

OBJECTIVE

This in vitro study investigates the antimicrobial efficacy of impregnation of commercially available aortic endografts (EG) with rifampicin (RIF) and nanocolloidal silver.

METHODS

Endografts were flushed with 50 mL of RIF 600 mg, 70 mL of a silver-based aqueous solution (AG), or 50 mL of phosphate-buffered saline (PBS) over 15 minutes. Endografts were then retrieved from the sheath and cut in 1 × 1 cm sized graft units (n = 80 of each impregnation), which were then incubated for 1 hour separately with inoculates containing 10⁶ or 10³ bacteria per milliliter (bact/mL) of each of the following bacteria: Staphylococcus epidermidis, Escherichia coli, multisensitive Staphylococcus aureus, and Pseudomonas aeruginosa. After sonication of the graft units, bacterial counts were measured by plating out twice the sonication solution on Mueller-Hinton plates.

RESULTS

RIF showed a statistically significant decrease of colony forming units per milliliter for all four bacterial strains in both concentrations compared with PBS and AG, except for 10³ bact/mL of E coli. AG showed a significant decrease of colony forming units per milliliter compared with PBS only for 10⁶ bact/mL of E coli and was statistically significantly inferior to RIF for all four bacterial strains in both concentrations with the exception of E coli at a concentration of 10³ bact/mL.

CONCLUSIONS

This in vitro study demonstrated infectivity resistance of aortic EG after flushing with RIF. Moreover, the feasibility of flushing aortic EG with a new silver-based agent could be demonstrated, but without statistically significant antimicrobial efficacy compared with native EG.

Surgical and medical interventions for abdominal aortic graft infections

BACKGROUND

Abdominal aortic graft infections are a major complication following abdominal aortic aneurysm surgery, with high morbidity and mortality rates. They can be treated surgically or conservatively using medical management. The two most common surgical techniques are in situ replacement of the graft and extra-anatomical bypass. Medical management most commonly consists of a course of long-term antibiotics. There is currently no consensus on which intervention (extra-anatomical bypass, in situ replacement, or medical) is the most effective in managing abdominal aortic graft infections. Whilst in emergency or complex situations such as graft rupture surgical management is the only option, in non-emergency situations it is often personal preference that influences the clinician's decision-making.

OBJECTIVES

To assess and compare the effects of surgical and medical interventions for abdominal aortic graft infections.

SEARCH METHODS

The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase, and CINAHL databases and WHO ICTRP and ClinicalTrials.gov trials registers to 2 December 2019. We also reviewed the bibliographies of the studies identified by the search and contacted specialists in the field and study authors to request information on any possible unpublished data.

SELECTION CRITERIA

We aimed to include all randomised controlled trials that used surgical or medical interventions to treat abdominal aortic graft infections. The definitions of abdominal aortic graft infections were accepted as presented in the individual studies, and included secondary infection due to aortoenteric fistula. We excluded studies presenting data on prosthetic graft infections in general, unless data specific to abdominal aortic graft infections could be isolated.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed all studies identified by the search. We planned to independently assess risk of bias of the included trials and to evaluate the quality of the evidence using the GRADE approach. Our main outcomes were overall mortality, amputation, graft re-infection, overall graft-related complications, graft-related mortality, acute limb ischaemia, and re-intervention.

MAIN RESULTS

We identified no randomised controlled trials to conduct meta-analysis.

AUTHORS' CONCLUSIONS

There is currently insufficient evidence to draw conclusions to support any treatment over the other. Multicentre clinical trials are required to compare different treatments for the condition.

In situ revascularization with rifampicin-soaked silver polyester graft for aortic infection: Results of a retrospective monocentric series of 18 cases

OBJECTIVE

To evaluate the short and long-term results of in situ prosthetic graft treatment using rifampicin-soaked silver polyester graft in patients with aortic infection.

MATERIAL AND METHOD

All the patients surgically managed in our center for an aortic infection were retrospectively analyzed. The primary endpoint was the intra-hospital mortality, secondary outcomes were limb salvage, persistent or recurrent infection, prosthetic graft patency, and long-term survival.

RESULTS

From January 2004 to December 2015, 18 consecutive patients (12 men and 6 women) were operated on for aortic infection. Six mycotic aneurysms and 12 prosthetic infections, including 8 para-entero-prosthetic fistulas, were treated. In 5 cases, surgery was performed in emergency. During the early postoperative period, we performed one major amputation and two aortic infections were persistent. Intra-hospital mortality was 27.7%. The median follow-up among the 13 surviving patients was 26 months. During follow-up, none of the 13 patients presented reinfection or bypass thrombosis.

CONCLUSION

This series shows that in situ revascularization with rifampicin-soaked silver polyester graft for aortic infection have results in agreement with the literature in terms of intra-hospital mortality with a low reinfection rate.

Systematic Review and Meta: Analysis of Aortic Graft Infections following Abdominal Aortic Aneurysm Repair

Introduction. Aortic graft infection (AGI) is a rare complication following AAA repair and is associated with high morbidity and mortality. Management is variable, and there are no evidence-based guidelines. The aim of this study was to systematically review and analyse management options for AGI.

Systematic Review and Meta-Analysis on the Management of Open Abdominal Aortic Graft Infections

OBJECTIVE

Aortic graft infection (AGI) is a disastrous complication with an incidence of 0.2-6% in operated patients. With little or no high quality evidence, the best treatment option remains unclear. Therefore, the literature on the management of open abdominal AGI was systematically reviewed to determine optimal treatment.

METHODS

In accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, a systematic review and meta-analysis was conducted for AGI. MEDLINE, Embase, and the Cochrane Database of Systematic Reviews were searched. Methodological quality was assessed using the Methodological Index for Non-randomised Studies (MINORS) score. Primary outcomes were 30 day mortality and one year survival. Secondary outcomes were survival, infection recurrence, limb salvage, and graft patency.

RESULTS

Of 1574 studies identified, 32 papers were included in the study. The overall quality of the studies was moderate, with an average MINORS score of 11.9. Pooled overall 30 day mortality and one year survival were 13.5% (95% CI 10.5-16.4) and 73.6% (95% CI 68.8-78.4), respectively. The lowest 30 day mortality and highest one year survival were found for in situ repair compared with extra-anatomic repair and for prosthetic grafts compared with venous grafts or arterial allografts. The infection recurrence rate was highest for prosthetic grafts.

CONCLUSIONS

There is a lack of well designed, qualitative comparative studies making conclusive recommendations impossible. The current best available data suggests that partial graft removal should be avoided and the lowest 30 day mortality and best one year survival are achieved with in situ repair using prosthetic grafts. Initiatives such as the MAGIC database to collaboratively collect prospective data are an important step forward in obtaining more solid answers on this topic.

A meta-analysis of outcomes of in-situ reconstruction after total or partial removal of infected abdominal aortic graft

INTRODUCTION

There is currently a lack of evidence for the relative effectiveness of partial resection (PR) and total resection (TR) before managing abdominal aortic graft infection (AGI). Most authorities agree that TR is mandatory for intracavitary AGI in patients with favorable conditions but there is an increasing number of patients with severe comorbidities for whom this approach is not suitable, resulting in a prohibitive mortality rate. The purpose of this study was to determine the most appropriate indication for TR or PR.

EVIDENCE ACQUISITION

A meta-analysis was conducted on the rates of early/late mortality, amputations and reinfection. A meta-regression was performed with eight variables: patient age, male prevalence, presence of virulent or nonvirulent organisms, urgency, omentoplasty and follow-up.

EVIDENCE SYNTHESIS

Twenty-one studies and 1052 patients were included. For TR and PR, the rates of early mortality and reinfection were 16.8% and 10.5%, 11% and 27%, respectively. For TR urgency and male gender were associated with increased rate of early mortality and male gender, PDF and virulent organisms were associated with increased risk of reinfection. For PR no statistical correlation was analyzable except for PDF with increased risk of reinfection.

CONCLUSIONS

Early mortality rates are higher for TR and reinfection rates are higher for PR. For TR early mortality increases in urgent cases and it is suggested that alternative option must be discussed, reinfection decreases in the presence of nonvirulent organisms and TR seems optimal. For TR and PR reinfection increases in presence of PDF and alternative technique may be more appropriate.

In vitro Evidence of Improved Antimicrobial Efficacy of Silver and Triclosan Containing Vascular Grafts Compared with Rifampicin Soaked Grafts

OBJECTIVES

The aim was to compare the antimicrobial efficacy of four different grafts: a standard graft (Intergard, IG), an IG graft soaked in rifampicin (IGrif), a silver impregnated graft (Intergard Silver, IGS), and a silver + triclosan impregnated graft (Intergard Synergy, IGSy).

METHODS

This was a seven day in vitro study. The IG, IGrif, IGS, and IGSy grafts were each contaminated separately with the following microorganisms: Staphylococcus epidermidis, Methicillin resistant Staphylococcus aureus (MRSA), Escherichia coli, and Candida albicans from both clinical and American Type Culture Collection (ATCC) origins. The in vitro antimicrobial efficacy was evaluated by time to kill assays at T0, T24h, T48h, T72h, and T168h. Bactericidal activity was defined as >3 log₁₀ reduction factor (logRF). Additionally, Rifampicin, triclosan and silver resistance development were screened.

RESULTS

As anticipated for the non-antimicrobial IG, all microorganism strains proliferated. The IGSy and the IGS showed a seven day bactericidal efficacy (>3 logRF) for all tested microorganisms. This efficacy was confirmed at all time points for IGSy only, demonstrating faster bactericidal efficacy than IGS. The IGrif demonstrated a seven day bactericidal efficacy against the ATCC MRSA only, while showing no activity against C. albicans and ATCC E. coli. Regarding ATCC S. epidermidis, clinical MRSA and clinical E. coli, IGrif, although bactericidal at earlier time points, lost its antimicrobial efficacy at seven days leading to the emergence of rifampicin resistant mutants in four of six, two of six, and two of six assays, respectively. Mutant strains were also detected in ATCC MRSA in one of six assays. No triclosan or silver resistance has emerged at T7days.

CONCLUSION

For all microorganisms tested, the Synergy graft combining silver with triclosan demonstrated a more sustainable and efficient seven day antimicrobial activity than the rifampicin soaked graft. The emergence of rifampicin resistant mutants suggests preference for a Synergy graft over a graft soaked in rifampicin, to prevent or treat an infection when a biological solution is not feasible.

Lateral femoral bypass for prosthetic arterial graft infections in the groin

OBJECTIVE

Prosthetic arterial graft infections (PAGIs) in the groin pose significant challenges in terms of revascularization options and risk of limb loss as well as associated morbidities. Although obturator canal bypass (OCB) has been suggested for revascularization of the extremity in these cases, moderate success rates and technical challenges have limited widespread use. Our study analyzed lateral femoral bypass (LFB) as an alternative approach for the treatment of groin PAGIs.

METHODS

This is a retrospective review of a prospectively maintained database of patients who underwent LFB for groin PAGIs at a single center from 2000 to 2017. Patients' data including demographics, comorbidities, perioperative complications, graft patency, and need for reintervention were used. Patients were observed after LFB with duplex ultrasound surveillance in an accredited noninvasive vascular laboratory every 3 months during the first year, followed by every 6 months for the second year and yearly thereafter. After isolation of the infected wound with sterile dressings, remote proximal and distal arterial exposure incisions were made. LFBs were tunneled under the inguinal ligament and lateral to the infected wound from an uninvolved inflow artery or bypass graft to an uninvolved outflow vessel.

RESULTS

A total of 19 LFBs were performed in 16 patients (mean age, 69 ± 12.6 years). Three LFBs were performed urgently for acute bleeding. Choice of conduit included 6 (31.6%) autogenous vein grafts, 10 (52.6%) cadaveric grafts, 2 (10.5%) rifampin-soaked Dacron grafts, and 1 (5.3%) polytetrafluoroethylene graft. Average follow-up was 33 months (range, 0-103 months). Major adverse events occurring within 30 days of the operation included one (5.3%) death and one (5.3%) graft excision for pseudoaneurysm. Primary patency and primary assisted patency at 12 and 24 months were 73% and 83%, respectively. One patient required an amputation 17 months after surgery after failure of repeated revascularization attempts. Overall limb salvage was 93.8% during this follow-up period.

CONCLUSIONS

In this series, LFB for management of groin PAGIs demonstrated higher patency and limb salvage rates compared with previous reports of OCB. Diligent postoperative duplex ultrasound surveillance is critical to the achievement of limb salvage and maintenance of graft patency. These results suggest that LFB, which is technically less complex than OCB, should be considered the first choice for revascularization in select cases of PAGIs involving the groin.

Vascular Graft Infections: An update

Vascular graft infection is a devastating complication of vascular reconstructive surgery. The infection can occur early in the postoperative period and is largely due to intraoperative contamination or by contiguous extension from a nearby infection. It can also occur years after implantation. Staphylococci remain the most common organisms and biofilm production makes eradication difficult. Factors commonly reported to predispose to vascular graft infection are periodontal disease, nasal colonization with Staphylococcus aureus, bacteremia, certain graft characteristics, diabetes mellitus, postoperative hyperglycemia, location of the incision, wound infection, and emergency procedure. Management consists of antibiotic and surgical therapy. Preventive methods are described.

Efficacy of Preoperative Antibiotic Therapy for the Treatment of Vascular Graft Infection

Objective: We aimed to assess the efficacy of preoperative antibiotic therapy for the treatment of prosthetic graft infection.

Materials and Methods: We retrospectively analyzed the treatment strategies used for managing patients with prosthetic vascular graft infections between 2000 and 2016. The patients were divided into two groups: early antibiotic (EA) group, those who were administered with antibiotics ≥2 weeks preoperatively and late antibiotic (LA) group, those who were administered with antibiotics <2 weeks preoperatively. We evaluated the outcomes including surgical procedures, length of hospital stay, and surgical revision.

Results: All the surgical procedures performed in the EA group were elective surgeries. Three of the 11 surgeries performed in the LA group were emergency surgeries (P=0.16). No significant differences were observed in the operative procedure (P=0.64), operation time (P=0.37), and blood loss (P=0.63) of the two groups. Although the length of postoperative hospital stay did not significantly differ (P=0.61), the total length of hospital stay was longer in the EA group (P=0.02). Surgical revisions were performed for five patients in the LA group and for none in the EA group (P=0.04).

Conclusion: Preoperative antibiotic therapy provided excellent outcomes in terms of avoiding surgical revisions in the treatment of vascular graft infection.

Vascular Graft Impregnation with Antibiotics: The Influence of High Concentrations of Rifampin, Vancomycin, Daptomycin, and Bacteriophage Endolysin HY-133 on Viability of Vascular Cells

Background

Rifampin-soaked synthetic prosthetic grafts have been widely used for prevention or treatment of vascular graft infections (VGIs).

This in vitro study investigated the effect of the antibiotics daptomycin and vancomycin and the new recombinant bacteriophage endolysin HY-133 on vascular cells, as potential alternatives compared to rifampin.

Material/Methods

Primary human ECs, vascular smooth muscle cells (vSMC), and fibroblasts were cultivated in 96-well plates and incubated with rifampin, daptomycin, vancomycin, and endolysin HY-133 for 24 h. Subsequently, after washing, cell viability was determined by measuring mitochondrial ATP concentration. Antibiotics were used in their corresponding minimum and maximum serum concentrations, in decimal multiples and in maximum soaking concentration. The experiments were performed in triplicate.

Results

The 10-fold max serum concentrations of rifampin, daptomycin, and vancomycin did not influence viability of EC and vSMC (100 μg/ml, p>0.170). Higher concentrations of rifampin (>1 mg/ml) significantly (p<0.001) reduced cell viability of all cell types. For the other antibiotics, high concentrations (close to maximum soaking concentration) were most cytotoxic for EC and vSMC and fibroblasts (p<0.001). Endolysin did not display any cytotoxicity towards vascular cells.

Conclusions

Results of this in vitro study show the high cytotoxicity of rifampin against vascular cells, and may re-initiate the discussion about the benefit of prophylactic pre-soaking in high concentrations of rifampin. Further studies are necessary to determine the influence of rifampin on the restoration of vessel functionality versus its prophylactic effect against VGIs. Future use of recombinant phage endolysins for alternative prophylactic strategies needs further investigations.

A Meta-Analysis of Outcomes After In Situ Reconstructions for Aortic Graft Infection

OBJECTIVE

To confirm the advantage of in situ reconstruction (ISR) over extra-anatomic reconstruction (EAR) for aortic graft infection and determine the most appropriate conduit including autogenous veins, cryopreserved allografts, and synthetic prosthesis (standard, rifampicin of silver polyesters).

METHODS

A meta-analysis was conducted with rate of mortality, graft occlusion, amputation, and reinfection. A meta-regression was performed with 4 factors: patients' age, presence of prosthetic-duodenal fistula (PDF), virulent organisms, or nonvirulent organisms.

RESULTS

In situ reconstruction over EAR seems to favor all events. For the 5 conduits used for ISR, according to operative mortality, age of the patients looks to have a positive correlation only for silver polyester and no conduit present any advantage in the presence of PDF. Reinfection seems to be not significantly different for the 5 conduits, and only autogenous veins appear to have a positive correlation with infecting organisms.

CONCLUSION

In situ reconstruction may be considered as first-line treatment. Our results suggest that silver polyesters appear to be most appropriate for older patients, and in order to limit reinfection, autogenous veins are probably the most suitable conduit.

Infected abdominal aortic aneurysm due to Escherichia coli

Early diagnosis of infected abdominal aortic aneurysm (IAAA) is still a medical challenge due to its diverse and non-specific symptoms and signs. The most common responsible pathogens are Salmonella, Staphylococcus, Campylobacter and Streptococcus species. The authors report the case of a 67-year-old man, admitted for high fever and finally diagnosed with Escherichia coli (E.coli)-related IAAA. The IAAA ruptured during the general anaesthesia induction, leading to an emergency surgery. The authors successfully proceeded to an open aneurysmectomy with extensive debridement and in situ graft replacement. This case emphasizes the potential for rapid IAAA expansion, its high-rupture risk and the importance of computed tomography as a diagnostic tool.

Editor's Choice - Management of Secondary Aorto-enteric and Other Abdominal Arterio-enteric Fistulas: A Review and Pooled Data Analysis

OBJECTIVES

To compare management strategies for secondary abdominal arterio-enteric fistulas (AEFs).

METHODS

This study is a review and pooled data analysis. Medline and Scopus databases were searched for studies published between 1999 and 2015. Particular emphasis was given to short- and long-term outcomes in relation to AEF repair type.

RESULTS

Two hundred and sixteen publications were retrieved, reporting on 823 patients. In-hospital mortality was 30.7%. Open surgery had higher in-hospital mortality (246/725, 33.9%), than endovascular methods (7/98, 7.1%, p < .001, OR 6.7, 95% CI 3-14.7, including staged endovascular to open surgery, 0/13, 0%). In-hospital mortality after graft removal/extra-anatomical bypass grafting was 31.2% (66/226), graft removal/in situ repair 34% (137/403), primary closure of the arterial defect 62.5% (10/16), and for miscellaneous open procedures 41.3% (33/80), p = .019. Among the subgroups of in situ repair, homografts were associated with a higher mortality than impregnated prosthetic grafts (p = .047). There was no difference in recurrent AEF-free rates between open and endovascular procedures. Extra-anatomical bypass/graft removal and in situ repair had a lower AEF recurrence rate than primary closure and homografts. Late sepsis occurred more often after endovascular surgery (2-year rates 42% vs. 19% for open, p = .001). The early survival benefit of endovascular surgery was blunted during follow-up, although it remained significant (p < .001). Within the in situ repair group, impregnated prosthetic grafts were associated with the worst overall and AEF related mortality free rates and vein grafts with the best. No recurrence, sepsis, or mortality was reported following staged endograft placement to open repair after a mean follow-up of 16.8 months (p = .18, p = .22, and p = .006, respectively, compared with patients in other groups).

CONCLUSIONS

Endovascular surgery, where appropriate, is associated with better early survival than open surgery for secondary AEFs. Most of this benefit is lost during long-term follow-up, implying that a staged approach with early conversion to in situ vein grafting may achieve the best results in selected patients.

Management of Infected Aortic Prosthetic Grafts

The management of infected prosthetic grafts is one of the most challenging problems facing vascular surgeons. High mortality and morbidity rates with traditional treatment have led many surgeons to consider different and novel strategies. Diagnosis is usually straightforward, but occasionally is unclear even after extensive clinical and radiologic investigations. Although routine total graft excision for all infected aortic grafts is still favored by some vascular surgeons, most favor only partial graft excision if only the distal limb of the graft is involved. Placement of in situ autologous vein or cryopreserved grafts have gained popularity, and investigations are continuing regarding the use of in situ antibiotic and silver-coated prosthetic grafts. In this article the authors review the incidence and etiology of aortic graft infections, methods to prevent these complications, the diagnosis of infected aortic grafts, and lastly the management of these complicated cases, including total graft excision and partial and complete graft preservation.

Use of Parietal Peritoneum for Aortic Stump Coverage Following Removal of an Infected Aortic Prosthesis

Aortic graft infections, albeit rare, pose a significant treatment challenge. Aortic stump disruption, in particular, is a potentially devastating complication. We describe a novel technique of using the parietal peritoneum to bolster a friable aortic stump in a 56-year-old man after an infected aortobifemoral graft was removed. The parietal peritoneal pedicle, in our experience, provides an effective alternative to reinforce an aortic stump when conventional coverage options have been exhausted.

Aortic Graft Infection: Update on Management and Treatment Options

Replacement of the abdominal aorta, whether by autogenous or prosthetic conduit, has been an a priori requisite in the vascular surgeon's armamentarium since its technical feasibility was described in the early 1950s. The Achilles' heel of this operation, in spite of the progress made over the last half century, is still, however, aortic graft infection. Though survival and limb salvage rates have improved over time—commensurate with advances in surgical technique, critical care, and antimicrobial agents—the prevention and treatment of aortic graft infection remains a formidable challenge to the vascular surgeon. The authors herein review the current literature on this topic with an emphasis on the surgical management options available and suggest an individualized operative strategy based on patient as well as microbial factors to attain the best possible outcome.

Deep Leg Vein Reconstruction for an Isolated Mycotic Common Iliac Artery Aneurysm in an HIV-Positive Patient

Isolated mycotic common iliac artery aneurysms are rare, and as such, there is no consensus opinion on management. Traditional surgical options include resection with extra-anatomic bypass, placement of allograft or antibiotic treated synthetic graft, or autogenous vein reconstruction. We report the case of a 46-year-old, human immunodeficiency virus-positive male who presented with a recurrent pneumonia and new onset of right lower quadrant abdominal pain associated with right lower extremity swelling. computed tomographic scan revealed an isolated 9.5 cm right common iliac artery aneurysm with no evidence of rupture. Preoperative blood cultures grew out Streptococcus pneumoniae. Operative repair included aneurysm resection and reconstruction using an autogenous femoropopliteal vein interposition graft from the ipsilateral thigh. The patient had an uneventful recovery with resolution of his lower extremity swelling and a normal duplex exam at follow-up. Large mycotic common iliac artery aneurysms can be successfully treated with aneurysm resection and reconstruction using an autogenous femoropopliteal vein conduit. This technique obviates the need for extra-anatomic bypass or other forms of reconstruction using prosthetic material.

[Management of bleeding and infections in the context of visceral surgery]

Bleeding and vascular infections are serious potential complications during abdominal general surgery. The management of bleeding depends on the extent and localization and can range from the application of hemostatics to vascular sutures, interpositioning and ligatures. The use of prosthetic biomaterials implanted endoluminally or during open reconstruction permits palliation of potentially fatal conditions. The overall incidence of infections involving vascular prostheses is relatively low because of routine antibiotic prophylaxis prior to surgery, refinements in sterilization and packaging of devices and careful adherence to aseptic procedural and surgical techniques. When infections occur detection and definitive therapy of the vascular prosthesis are often delayed and the management is complex and tedious. Infections involving vascular prostheses are difficult to eradicate and in general, surgical therapy is required often coupled with excision of the prosthesis. Keys to success include accurate diagnostics to identify the organism and extent of graft infections, specific long-term antibiotic therapy and well-planned surgical interventions to excise and replace the infected graft and sterilize the local tissue. Regardless of the technique used to eradicate graft infections, success is measured by patient survival, freedom from recurrent infection and patency of revascularization. Even when treatment is successful, the morbidity associated with vascular graft infections is considerable. Aortoenteric fistulas (AEF) are a rare (incidence < 1.5 %) but often fatal complication. Primary diagnosis of AEF remains difficult. Computed tomography (CT) and fluorodeoxyglucose positron emission tomography CT (FDG-PET-CT) are the diagnostic tools of choice. Therapy consists of an urgent individualized interdisciplinary surgical approach with primary axillofemoral bypass and secondary prosthesis explantation or in situ replacement and subsequent bowel resection. Endovascular aortic repair (EVAR) is reserved for primary aortoenteric fistulas in patients with no signs of infection or in emergency cases as a bridging method.

Comparison of the Antimicrobial Properties of Silver Impregnated Vascular Grafts with and without Triclosan

OBJECTIVES

The aim was to compare the antimicrobial efficacy of the silver impregnated collagen coated polyester vascular graft (IGS) with an identical graft combining silver and triclosan (IGSy).

METHODS

This was an in vitro study. A non-antimicrobial collagen polyester vascular graft served as control (IG). The IG, IGS, and IGSy grafts were contaminated separately with inoculates of each of the following micro-organisms: Staphylococcus epidermidis (SE), methicillin resistant Staphylococcus aureus (MRSA), and Escherichia coli producing extended spectrum beta-lactamase (ESBL-EC) or Candida albicans (CA). MRSA, ESBL-EC, and CA were obtained from retrieved infected grafts. The in vitro antimicrobial efficacies of the contaminated grafts were evaluated by time to kill assays over a 24 hour period in accordance with CLSI Guideline M26-A. All assays were repeated six times. Bacterial survival numbers were obtained at 1, 4, 8, and 24 hours using a standard plate count procedure. Bactericidal activity was defined as a 3 log10 reduction factor (logRF). To calculate the overall difference in the mean log10 CFU/mL within 24 hours, a one way ANOVA with a Bonferroni correction was calculated separately for each graft.

RESULTS

The IG graft showed an increase in the number of viable organisms for the four strains tested. IGSy offered better antimicrobial properties than IGS for both ESBL-EC and MRSA, since only the IGSy graft achieved > 3 logRF and fulfilled the standard criteria for bactericidal activity at 24 hours with 3.78 and 4.08 logRF, respectively. For samples inoculated with SE and CA, both antimicrobial grafts achieved 24 hour bactericidal activity with > 3 logRF. However, for CA the one-way ANOVA analysis demonstrated that the IGSy graft performed differently in terms of speed of antimicrobial action, appearing more active as early as 4 hours following inoculation (p = .007).

CONCLUSION

In the in vitro conditions, the Synergy vascular graft combining silver with triclosan demonstrated better short-term antimicrobial activity than the silver graft for all micro-organisms tested.

Multidisciplinary Treatment Approach for Prosthetic Vascular Graft Infection in the Thoracic Aortic Area

Prosthetic vascular graft infection in the thoracic aortic area is a rare but serious complication. Adequate management of the complication is essential to increase the chance of success of open surgery. While surgical site infection is suggested as the root cause of the complication, it is also related to decreased host tolerance, especially as found in elderly patients. The handling of prosthetic vascular graft infection has been widely discussed to date. This paper mainly provides a summary of literature reports published within the past 5 years to discuss issues related to multidisciplinary treatment approaches, including surgical site infection, timing of onset, diagnostic methods, causative pathogens, auxiliary diagnostic methods, antibiotic treatment, anti-infective structures of vascular prostheses, surgical treatment, treatment strategy against infectious aortic aneurysms, future surgical treatment, postoperative systemic therapy, and antimicrobial stewardship. A thorough understanding of these issues will enable us to prevent prosthetic vascular graft infection in the thoracic aortic area as far as possible. In the event of its occurrence, the early introduction of appropriate treatment is expected to cure the disease without worsening of the underlying pathological condition.

Medical treatment of prosthetic vascular graft infections: Review of the literature and proposals of a Working Group

More than 400000 vascular grafts are inserted annually in the USA. Graft insertion is complicated by infection in 0.5-4% of cases. Vascular graft infections (VGIs) are becoming one of the most frequent prosthesis-related infections and are associated with considerable mortality, ranging from 10 to 25% within 30 days following the diagnosis. Treatment of VGI is based on urgent surgical removal of the infected graft followed by prolonged antibiotherapy. Data regarding the best antibiotherapy to use are lacking since no well designed trial to study antimicrobial treatment of VGI exists. Moreover, since VGIs demonstrate very specific pathophysiology, guidelines on other material-related infections or infective endocarditis treatment cannot be entirely applied to VGI. A French multidisciplinary group gathering infectious diseases specialists, anaesthesiologists, intensivists, microbiologists, radiologists and vascular surgeons was created to review the literature dealing with VGI and to make some proposals regarding empirical and documented antibiotic therapy for these infections. This article reveals these proposals.

Surgical and antimicrobial treatment of prosthetic vascular graft infections at different surgical sites: a retrospective study of treatment outcomes

Objective

Little is known about optimal management of prosthetic vascular graft infections, which are a rare but serious complication associated with graft implants. The goal of this study was to compare and characterize these infections with respect to the location of the graft and to identify factors associated with outcome.

Methods

This was a retrospective study over more than a decade at a tertiary care university hospital that has an established multidisciplinary approach to treating graft infections. Cases of possible prosthetic vascular graft infection were identified from the hospital's infectious diseases database and evaluated against strict diagnostic criteria. Patients were divided into groups according to the locations of their grafts: thoracic-aortic, abdominal-aortic, or peripheral-arterial. Statistical analyses included evaluation of patient and infection characteristics, time to treatment failure, and factors associated specifically with cure rates in aortic graft infections. The primary endpoint was cure at one year after diagnosis of the infection.

Results

Characterization of graft infections according to the graft location did show that these infections differ in terms of their characteristics and that the prognosis for treatment seems to be influenced by the location of the infection. Cure rate and all-cause mortality at one year were 87.5% and 12.5% in 24 patients with thoracic-aortic graft infections, 37.0% and 55.6% in 27 patients with abdominal-aortic graft infections, and 70.0% and 30.0% in 10 patients with peripheral-arterial graft infections. In uni- and multivariate analysis, the type of surgical intervention used in managing infections (graft retention versus graft replacement) did not affect primary outcome, whereas a rifampicin-based antimicrobial regimen was associated with a higher cure rate.

Conclusions

We recommend that future prospective studies differentiate prosthetic vascular graft infections according to the location of the grafts and that rifampicin-based antimicrobial regimens be evaluated in clinical trials involving vascular graft infections caused by staphylococci.

Mycotic abdominal aortic aneurysm caused by Campylobacter fetus: a case report and literature review

Campylobacter spp. usually cause gastrointestinal infections, but among them, Campylobacter fetus is a well-known organism causing mycotic abdominal aortic aneurysm (MAAA), which requires proper surgical intervention and antibiotic therapy. We report a 65-year-old man who was successfully treated by an in situ operation using a rifampicin (RFP)-bonded J-Graft for C. fetus-induced MAAA. We performed a review of the English literature on MAAA caused by C. fetus and summarized the results of the cases (28 cases). All but 2 of the patients (92.9%) were men. Blood culture and arterial wall culture were positive in 63% and 73.1% of the cases, respectively. Aneurysm rupture was seen in half of the patients, and approximately half of those patients died. Among the 18 patients who underwent in situ graft replacement, only 1 patient (5.6%) died after surgery. Antibiotic therapy was performed for more than 1 month in most cases, and overall mortality rate was 25.9% (7 of 27 cases, 3 deaths before the operation and 4 deaths after surgery). Although extra-anatomic bypass has been conventionally performed after complete resection of an MAAA, the utility of in situ surgery has generally been recognized. Our review suggests that the in situ operation can be a choice also in cases of C. fetus-associated MAAA. Furthermore, our case suggested the clinical utility of a newly manufactured prosthetic graft, J-Graft, for such surgical treatment.

A case of in-situ reconstruction with a rifampicin-bonded gelatin-sealed woven dacron graft for prosthetic graft infection with pseudoaneurysms after ascending aortic replacement for type a dissection

A 74-year-old woman underwent replacement of the ascending aorta for acute type A aortic dissection. The patient suffered from bacteremia postoperatively and repeated computed tomography showed an increasing diameter of pseudoaneurysms at the site of the proximal anastomosis due to graft infection. Re-mechanical Bentall operation and arch replacement were therefore performed using a composite graft of a rifampicin-bonded gelatin-sealed 24-mm woven Dacron graft and a mechanical valve. The postoperative course was uneventful. We report the successful in situ reconstruction using the above-mentioned Dacron graft and describe the preparation of the rifampicin solution using a surfactant.