Conservative treatment of vascular prosthetic graft infection is associated with high mortality

Fungal versus non-fungal supra-inguinal prosthetic vascular graft infections: A cohort study

OBJECTIVES

Fungal prosthetic vascular graft infections are rare and mainly supra-inguinal. Current guidelines are based on the few studies that have specifically investigated this population, with few risk factors described. The objective of this study is to compare fungal and non-fungal supra-inguinal prosthetic vascular graft infections (PVGI), describing their specificities, identifying risk factors, and evaluating outcomes.

PATIENTS AND METHODS

This is a single-center retrospective cohort study carried out at the Pitié-Salpêtrière Hospital in Paris, including all patients who were treated for a supra-inguinal PVGI between January 1st, 2009 and February 28th, 2021. Preoperative, intraoperative and postoperative data were compared between fungal and non-fungal PVGI.

RESULTS

Out of the 475 patients screened, 148 developed a supra-inguinal PVGI: 32 fungal and 116 non-fungal. Factors independently associated with fungal PVGI were presence of a prostheto-digestive fistula (OR 5.98; 95% CI 2.29-15.62) and preoperative antibiotic therapy of seven days or more (OR 2.87; 95% CI 1.12-7.38). Mortality rate at 180 days was significantly higher for fungal as compared to non-fungal PVGIs (38% vs. 16% p = 0.009) and for fungal PVGI with prostheto-digestive fistula. However, there was no statistically significant relation between mortality due to prostheto-digestive fistula in contrast with fungal PVGI alone (p = 0.21).

CONCLUSION

Prostheto-digestive fistula was strongly associated with fungal PVGI, which leads us to suggest that in such cases, an anti-fungal agent should be prescribed.

Performance of the BioIntegral Bovine Pericardial Graft in Vascular Infections: VASCular No-REact Graft Against INfection Study

BACKGROUND

Vascular graft and endograft infections (VGEI) and native vessel infections (NVI) remain considerable challenges in vascular surgery, leading to high mortality and morbidity rates. Although in situ reconstruction is the preferred treatment, the material of choice is still a source of debate. Autologous veins are considered the first choice; however, xenografts may be an acceptable alternative. The performance of a biomodified bovine pericardial graft is assessed when implemented in an infected vascular area.

METHODS

This is a prospective multicenter cohort study. Patients who underwent reconstruction for VGEI or NVI with a biomodified bovine pericardial bifurcated or straight tube graft were included from December 2017 until June 2021. The primary outcome measure was reinfection at mid-term follow-up. Secondary outcome measures included mortality, patency, and amputation rate.

RESULTS

Thirty-four patients with vascular infections were included, of which 23 (68%) had an infected Dacron prosthesis after primary open repair and 8 (24%) had an infected endovascular graft. The remaining 3 (9%) had infected native vessels. At secondary repair, 3 (7%) patients had an in situ aortic tube reconstruction, 29 (66%) had an aortic bifurcated reconstruction, and 2 (5%) had an iliac-femoral reconstruction. At 1-year follow-up after the BioIntegral bovine pericardial graft reconstruction, the reinfection rate was 9%. The 1-year infection-related and procedure-related mortality rate was 16%. The occlusion rate was 6% and in total 3 patients underwent a lower limb amputation during the 1-year follow-up period.

CONCLUSIONS

In situ reconstruction as treatment of (endo)graft and native vessel infections remains a challenge and reinfection looms as a potential consequence. In cases where time is of essence or when autologous venous repair is not feasible, a swift available solution is needed. The BioIntegral biomodified bovine pericardial graft may be an option as it shows reasonable results in terms of reinfection, in aortic tube and bifurcated grafts.

Sonication of Vascular Grafts and Endografts to Diagnose Vascular Graft Infection: a Head-To-Head Comparison with Conventional Culture and Its Clinical Impact

Vascular graft and endograft infection (VGEI) is a severe complication associated with high mortality and is often challenging to diagnose. For the definitive microbiological diagnosis, sonication of vascular grafts may increase the microbiological yield of these biofilm-associated infections. The objective of this study was to determine whether sonication of explanted vascular grafts and endografts results in a higher diagnostic accuracy than conventional culture methods and aids in clinical decision-making. A prospective diagnostic study was performed comparing conventional culture with sonication culture of explanted vascular grafts in patients treated for VGEI. Explanted (endo)grafts were cut in halves and were either subjected to sonication or conventional culture. Criteria based on the Management of Aortic Graft Infection Collaboration (MAGIC) case definition of VGEI were used for definitive diagnosis. The relevance of sonication cultures was assessed by expert opinion to determine the clinical impact on decision-making. Fifty-seven vascular (endo)graft samples from 36 patients (four reoperations; 40 episodes) treated for VGEI were included; 32 episodes were diagnosed with VGEI. Both methods showed a positive culture in 81% of the cases. However, sonication culture detected clinically relevant microorganisms that went unnoticed by conventional culturing in 9 out of 57 samples (16%, 8 episodes) and provided additional relevant information regarding growth densities in another 11 samples (19%, 10 episodes). Sonication of explanted vascular grafts and endografts improves the microbiological yield and aids in the clinical decision-making for patients with a suspected VGEI compared to conventional culture alone. IMPORTANCE Sonication culture of explanted vascular grafts was shown to be a noninferior method compared to conventional culturing in diagnosing vascular graft and endograft infection (VGEI). Moreover, sonication culture has probable additional value in microbiological characterization of VGEI by giving more detailed information on growth densities, especially when the conventional culture shows intermediate growth. In this prospective design, for the first time, a direct comparison is made between sonication culturing and conventional culturing in VGEI, while taking clinical interpretation into account. Therefore, this study is another step toward a more accurate microbiological diagnosis of VGEI, influencing clinical decision-making.

Infection of Vascular Prostheses: A Comprehensive Review

Vascular graft or endograft infection (VGEI) is a complex disease that complicates vascular-surgery and endovascular-surgery procedures and determines high morbidity and mortality. This review article provides the most updated general evidence on the pathogenesis, prevention, diagnosis, and treatment of VGEI. Several microorganisms are involved in VGEI development, but the most frequent one, responsible for over 75% of infections, is Staphylococcus aureus. Specific clinical, surgical, radiologic, and laboratory criteria are pivotal for the diagnosis of VGEI. Surgery and antimicrobial therapy are cornerstones in treatment for most patients with VGEI. For patients unfit for surgery, alternative treatment is available to improve the clinical course of VGEI.

Diagnosis and treatment of vascular graft and endograft infections: a structured clinical approach

A vascular graft or endograft infection (VGEI) is a severe complication that can occur after vascular graft or endograft surgery and is associated with high morbidity and mortality rates. A multidisciplinary approach, consisting of a team of vascular surgeons, infectious diseases specialists, medical microbiologists, radiologists, nuclear medicine specialists, and hospital pharmacists, is needed to adequately diagnose and treat VGEI. A structured diagnostic, antibiotic, and surgical treatment algorithm helps clinical decision making and ultimately aims to improve the clinical outcome of patients with a VGEI.

Bovine pericardial patch: A good alternative in femoral angioplasty

OBJECTIVE

Bovine pericardial patch (BPP) is currently used in femoral angioplasty as an alternative for autologous vein patch (AVP), but studies comparing the results of the two methods are scarce. In this retrospective study, we aimed to discover the differences between BPP and AVP closure in long-term durability.

METHODS

This study consisted of all femoral endarterectomies with BPP closure performed in Helsinki University Hospital from January 1, 2014, to December 31, 2017. For comparison, the same number of consecutive patients who underwent femoral endarterectomy with AVP closure from January 1, 2014, to October 16, 2016, were reviewed. Follow-up ended December 31, 2020. The mean follow-up was 19 months (range, 0-74 months) in the BPP group and 22 months (range, 0-79 months) in the AVP group. The primary endpoint was primary patency. Secondary endpoints were restenosis at patch site detected by imaging or perioperatively, patch rupture, and deep surgical wound infection. Propensity score analysis was performed for adjustment of differences between the AVP and BPP groups.

RESULTS

Overall primary patency was superior in the AVP group compared with the BPP group: at 1 year, 96.5% vs 85.0% and at 5 years, 83.0% vs 72.3% (P = .04). In propensity score-matched pairs (n = 92), no difference was found between the groups in primary patency: 95.7% and 95.7% at 1 year and 92.5% and 78.6% at 5 years (P = .861) or in freedom from restenosis: 100% and 100% at 1 year and 89.1% and 84.0% at 5 years (P = .057). Deep wound infections occurred slightly more often after BPP closure (8%) than after AVP closure (4%), but the difference was not statistically significant (P = .144). There were no patch ruptures in the BPP group, but in the AVP group, there were five ruptures (3.5%) (P = .024).

CONCLUSIONS

BPP is compatible to AVP in femoral endarterectomy in patency and can be regarded as the safer choice considering the risk of patch rupture.

[18F]-Fludeoxyglucose Positron Emission Tomography/Computed Tomography with Radiomics Analysis in Patients Undergoing Aortic In-Situ Reconstruction with Cryopreserved Allografts

BACKGROUND

The aim of this study was to evaluate the effectiveness of positron emission tomography/computed tomography with [¹⁸F]-fludeoxyglucose (FDG-PET/CT) and radiomics analysis in detecting differences between the native aorta and the abdominal aortic allograft after the total eradication of infection in patients undergoing infected graft removal and in situ reconstruction with cryopreserved allografts.

METHODS

Between January 2008 and December 2018, 56 vascular reconstructions with allografts have been performed at our department. The present series included 12 patients undergoing abdominal aortic in situ reconstruction with cryopreserved allografts. During the follow-up, all patients underwent a total-body [¹⁸F]FDG PET/CT with subsequent radiomics analysis. In all patients, a comparative analysis between the data extracted from native aorta and cryopreserved graft for each patient was performed.

RESULTS

All patients were male with a mean age of 72.8 years (range 63-84). Mean duration of follow-up was 51.3 months (range 3-120). During the follow-up, 2 patients (16.7%) needed a redo allograft-related surgical intervention. Overall, the rate of allograft dilatation was 33.3%. No patient had a redo infection during the follow-up. Radiomics analysis showed a different signature of implanted allograft and native aorta. Comparative analysis between the native aortas and cryopreserved allografts (dilated or not) showed several statistical differences for many texture features.

CONCLUSIONS

The higher metabolic activity of allografts could indicate a state of immune-mediated degeneration. This theory should be proven with prospective, multicentric studies with larger sample sizes.

Outcomes of patients with aortic vascular graft and endograft infections initially contra-indicated for complete graft explantation

OBJECTIVE

Complete excision in patients with aortic vascular graft and endograft infections (VGEIs) is a significant undertaking, and many patients never undergo definitive treatment. Knowing their fate is important to be able to assess the risks of graft excision vs alternative strategies. This study analyzed their life expectancy and sepsis-free survival.

METHODS

VGEIs were diagnosed according to the Aortic Graft Infection (MAGIC) criteria, and patients turned down for graft removal from November 2006 to December 2020 were included. Primary endpoints were aortic-related and sepsis-free survival estimated using the Kaplan-Meier method. A Cox proportional hazards regression analysis was used to compute the hazard ratio (HR) and 95% confidence interval (CI) as estimates of survival without sepsis.

RESULTS

Seventy-four patients were included, with a median age of 71 years (range, 63-79 years). The index aortic repair was either open (n = 33; 44.6%), endovascular (n = 19; 25.7%), or hybrid (n = 22; 29.7%). Causative organisms were identified in 56 patients (75.7%). At presentation, 26 patients (35.1%) required salvage surgery, open (n = 22; 29.7%) or endovascular (n = 8; 10.8%), and 17 radiological drainage (23.0%). During follow-up, eight required drainage and 11 (14.9%) graft removal (five complete). Infectious complications included pseudoaneurysms (n = 14; 18.9%), rupture (n = 9; 12.2%), gastro-intestinal bleeding (n = 13; 17.6%), septic embolisms (n = 4; 5.4%), and thrombosis (n = 12; 16.2%). In-hospital mortality was 20.3% (n = 15), freedom from aortic-related death and overall survival was 77.1% (95% CI, 65.2%-85.3%) and 70.4% (95% CI, 58.3%-79.7%) at 1 year, and 61.7% (95% CI, 46.1%-74.0%) and 43.1% (95% CI, 29.2%-56.3%) at 5 years. Sepsis recurrence occurred in 37 patients (50.0%). Seven (16.3%) developed acquired antimicrobial resistance. Malnutrition (HR, 3.3; 95% CI, 1.4-7.6; P = .005), hemorrhagic shock at presentation (HR, 2.9; 95% CI, 1.0-8.2; P = .048), aorto-enteric fistulae (HR, 3.3; 95% CI, 1.3-8.4; P = .011), fungal coinfection (HR, 3.5; 95% CI, 1.2-11.5; P = .030), and infection with resistant micro-organisms (HR, 3.1; 95% CI, 1.1-8.3; P = .023) were significantly associated with worse survival without sepsis.

CONCLUSIONS

In-hospital and aortic-related mortality were significant, but with salvage surgery and antibiotic therapy, the median survival was 3 years. Sepsis recurrence remained frequent, and further procedures were needed. These outcomes should be considered when graft excision is proposed. Known predictors of adverse outcomes should become important points for discussion in multidisciplinary team meetings.

Contemporary results with the biosynthetic glutaraldehyde denatured ovine collagen graft (Omniflow II) in lower extremity arterial revascularization in a septic context

OBJECTIVE

Prosthetic peripheral vascular graft infections are poorly evaluated, despite a grim prognosis with high mortality and major amputation rates. The vascular substitute of choice remains controversial when autologous veins are unavailable. The main objective of this study was to evaluate the mid-term results of a new alternative biosynthetic collagen graft (Omniflow II®) in an infected field in patients with unavailable or unsuitable autologous saphenous vein.

METHODS

This retrospective, observational, multicentric study included all consecutive patients in whom an Omniflow II® graft was used for infra-inguinal revascularization in the context of sepsis from January 2015 to January 2020. The primary endpoint was freedom from major amputation; secondary endpoints were 30-day mortality, perioperative morbidity, and estimated survival, patency, and freedom from reinfection estimated using the Kaplan-Meier method.

RESULTS

Twenty-nine patients (27 men, median age 69 years (IQR:60;76) were included. Fever was present in 58.6% of cases, a septic rupture in 17.9%, and a pseudo-aneurysm in 25.0%. The 30-day mortality rate was 3.4% (septic shock). The median follow-up reached 49 months. At 1 and 3 years, the estimated freedom from major amputation was 88.4% and 83.9%, survival was 96%, primary patency was 74.6% and 65.8%, secondary patency was 82.1% and 77.7% and reinfection free-survival was 85.6%. There were 7 occlusions (1 iliofemoral, 1 below-knee, and 5 above-knee bypasses), 3 explantations for persistent sepsis, 4 reinfections (all within the first 6 months which led to 1 death and 3 major amputations), and a total of 4 major amputations. The risk of major amputation increased with bypass reinfection (p=.004), occlusion (p=.005), and polymicrobial infection (p=.05).

CONCLUSION

In a septic context, the Omniflow II® bioprosthetic graft represents an acceptable vascular substitute in the absence of an autologous vein. It provides acceptable freedom from major amputation and reinfection considering the seriousness of this pathology. This usage remains outside the instructions for use, it is, therefore, essential to pursue longer-term studies in larger cohorts.

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.

[18F] FDG PET/CT can improve the diagnostic accuracy for aortic endograft infection

PURPOSE

Aortic endograft infection (EI) can result in potentially life-threatening vascular complications. Unfortunately, it is difficult to obtain a correct diagnosis at an early stage in many patients. This report aims at validating the use of [¹⁸F] FDG PET/CT imaging for suspected endograft infections in a prospectively collected cohort of patients treated with EVAR and TEVAR.

MATERIALS AND METHODS

During a 14-year period, 366 patients required aortic stent graft. All procedures were performed electively, except for one patient. Among these 366 patients, eleven patients (3%) were suspected to have aortic EI. Contrast-enhanced CT and FDG PET/CT were performed in all 11 patients. Medical charts and imaging were analysed for these 11 cases, with initial positive CT.

RESULTS

The final diagnosis of EI was established in seven (1,9%) based on clinical features, laboratory investigations and a significant [¹⁸F] FDG uptake in the aortic graft as well as the aortic wall. The median time from the initial EVAR/TEVAR to diagnosed infection was 180 days. During follow-up, the seven patients had a second PET/CT that was compared with the initial evaluation, decreased uptake was correlated with clinical improvement.

CONCLUSIONS

Contemporary diagnostic imaging for a potentially lethal endograft infection lacks precision, this observational study illustrates the potential clinical value of [¹⁸F] FDG PET/CT in the management of aortic EI. [¹⁸F] FDG PET/CT constitutes an imaging modality able to confirm the diagnosis, monitor disease progression as well as the effect of pharmaceutical treatment and detect relapse.

Use of rifampicin and graft removal are associated with better outcomes in prosthetic vascular graft infection

OBJECTIVES

Prosthetic vascular graft infection (PVGI) is a very severe disease. We aimed to determine the factors associated with treatment failure.

METHODS

Patients admitted to two University Hospitals with PVGI were included in this retrospective study. PVGI was classified as possible, probable or proven according to an original set of diagnostic criteria. We defined treatment failure if one of the following events occurred within the first year after PVGI diagnosis: death and infection recurrence due to the same or another pathogen.

RESULTS

One hundred and twelve patients were diagnosed with possible (n = 26), probable (n = 22) and proven (n = 64) PVGI. Bacterial documentation was obtained for 81% of patients. The most frequently identified pathogen was Staphylococcus aureus (n = 39). Surgery was performed in 96 patients (86%). Antibiotics were administered for more than 6 weeks in 41% of patients. Treatment failure occurred in 30 patients (27.5%). The factors associated with a lower probability of treatment failure were total removal of the infected graft (OR = 0.2, 95% CI [0.1-0.6]), rifampicin administration (OR = 0.3 [0.1-0.9]) and possible PVGI according to the GRIP criteria (OR = 0.3 [0.1-0.9]).

CONCLUSIONS

Treatment failure occurred in 27.5% of patients with PVGI. Total removal of the infected graft and rifampicin administration were associated with better outcomes.

[Case of extra-anatomical prosthetic repair in local infection of a bifurcated aortofemoral graft]

Presented in the article is a clinical case report regarding successful treatment of a patient with infection of a vascular graft after bifurcation aortofemoral bypass grafting by means of partial removal of the graft's branch with extra-anatomical graft-to-femur prosthetic repair through the iliac wing. The patient was admitted 6 months after bifurcation aortofemoral bypass grafting with a purulent and ligature fistula, discharge in the inguinal area. The findings of computed tomography showed no infection of the central anastomosis in the retroperitoneal space, with however periprosthetic infection in the area of the distal branch and severe comorbid background, thus not allowing complete removal of the prosthesis. A decision was made to perform operation in the scope of resection of the graft's branch, with extra-anatomical bypass grafting through a hole created in the iliac wing and debridement of the wound in the groin. In the postoperative period, no lower limb ischemia was observed, with blood circulation compensated completely. The patient was discharged in a satisfactory condition on POD 64 with no signs of either local or systemic infection.

Controlling Experimental Parameters to Improve Characterization of Biomaterial Fouling

Uncontrolled protein adsorption and cell binding to biomaterial surfaces may lead to degradation, implant failure, infection, and deleterious inflammatory and immune responses. The accurate characterization of biofouling is therefore crucial for the optimization of biomaterials and devices that interface with complex biological environments composed of macromolecules, fluids, and cells. Currently, a diverse array of experimental conditions and characterization techniques are utilized, making it difficult to compare reported fouling values between similar or different biomaterials. This review aims to help scientists and engineers appreciate current limitations and conduct fouling experiments to facilitate the comparison of reported values and expedite the development of low-fouling materials. Recent advancements in the understanding of protein-interface interactions and fouling variability due to experiment conditions will be highlighted to discuss protein adsorption and cell adhesion and activation on biomaterial surfaces.

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.

A case report of a unique aorto-bifemoral graft infection and its treatment

In this study, we report a unique case of aorto-bifemoral graft infection, which developed in a 47-year-old male patient after endovascular aortic aneurysmal repair (EVAR) and extra anatomic axillo-femoral bypass. The patient had previously been treated by EVAR for an infrarenal abdominal aortic aneurysm. Earlier, the EVAR was blocked by a thrombosis and treated with an extra-anatomic axillo femoral bypass, which then became occluded. The patient was then treated with an aorto-bifemoral bypass using a Dacron Y graft. A few months later, he was referred to our cardiovascular center with high body temperature, weight loss, inability to stand and walk, and very serious sepsis. A computed abdominal tomography scan revealed that a part of the graft proximal to the bifurcation had totally eroded into the proximal jejunum. We treated this patient with multiple surgeries, antibiotic administrations and hypochlorous acid irrigation without graft excision, which carries a high morbidity and mortality risks.

Treatment of prosthetic vascular graft infection in the groin with ultrasound debridement: A case report

Introduction

Prosthetic graft infection (PGI) is associated with low patient survival rates. The effectiveness of ultrasound debridement in chronic wound healing has been previously reported; however, data on the use of ultrasound technology and its effect on the treatment of PGI are still lacking. We report a case in which PGI in the groin was managed by graft removal using ultrasound debridement.

Presentation of case

A 70-year-old man was diagnosed with chronic limb-threatening ischemia and underwent a femoral-femoral bypass with a polytetrafluoroethylene graft. Eight months postoperatively, he developed an infection at the femoral incision site. Graft removal was performed using ultrasound debridement. The estimated blood loss was 10 mL. The wound healed, and the patient has remained in good health for 2 years postoperatively.

Discussion

When the ultrasonic probe is applied to the wound, ultrasonic energy penetrates into the tissue, and a fibrinolytic action removes necrotic or infected tissue without removing healthy tissue, thereby minimizing bleeding. Using this technique, we were able to perform effective debridement at not only the wound but also the anastomosis.

Conclusion

It is our opinion that this technique can be used to achieve adequate debridement with little bleeding during graft removal and may provide a new option for the treatment of PGI.

99mTC-white blood cell scintigraphy with SPECT/CT in the diagnosis of vascular graft infection

AIM

Vascular graft infection is a rare complication with a high morbidity and mortality. Early diagnosis is essential to establish an adequate treatment. We assess the accuracy of 99mTc-WBC scintigraphy with SPECT/CT in the diagnosis of vascular graft infection.

MATERIALS AND METHODS

We retrospectively analyzed thirty ^99mTc-WBC scintigraphies with SPECT/CT performed in thirty patients with suspicion of vascular prosthesis infection. Studies were considered positive for graft infection if the intensity of activity involving the graft was greater than the liver or bone marrow activity (spine and pelvis).

RESULTS

Final diagnosis of infection was established in 10 patients, based on Fitzgerald criteria. Scintigraphy was positive in 11 patients. No false negatives were obtained. The values of sensitivity and specificity were 100% and 95%, respectively, with a PPV of 91% and a NPV of 100%. Twenty five patients had a CT performed prior to scintigraphy, in 9 cases the result was positive and in the remaining 16 was negative. CT sensitivity and specificity obtained in our study were 62.5% and 76% respectively, with a PPV of 55.6% and a NPV of 81.3%. Diagnosis of infection led to prosthesis exeresis in 8 cases (all of them had a positive microbiological study of the extracted material), while the remaining 2 patients were treated with antibiotic therapy alone due to high surgical risk.

CONCLUSION

Our results suggest a high accuracy for ^99mTc-WBC scintigraphy with SPECT/CT in the assessment of clinically suspected arterial graft infection.

Genuine impact of 18F-fluorodeoxyglucose positron emission tomography with contrast-enhanced computed tomography in clinching the diagnosis and follow-up response assessment of vascular graft infections

Vascular graft infection (VGI) is a rare and severe complication after vascular surgery associated with significant morbidity and mortality, but the diagnosis is not always straightforward due to its variable and nonspecific clinical signs. Computed tomography (CT) scan is considered to be the diagnostic tool of choice for advanced VGI, but there is a high incidence of false-negative results, especially in low-grade infections. ¹⁸F-Fluorodeoxyglucose positron emission tomography with contrast-enhanced CT (¹⁸F-FDG PET-CT) imaging can serve as an effective alternative tool for assessment of suspected VGI and also provide accurate anatomic localization of the infective focus. Here, we describe three cases of VGI with various clinical presentations where the site of infection was diagnosed, confirmed, and documented with the help of ¹⁸F-FDG PET-CT imaging.

Results of the Proliferative Activity’s Analysis of Bifidobacterium Exometabolites in Regard to Hospital Isolates from Patients after Vascular Synthetic Prosthetics Implantation

Problems ofdevelopment of purulent septic complications in vascular surgery during the usage of synthetic prosthetics for shunting and arterial prosthetics are described in this work.Leading factors of development of prosthetic infection are described. Specialties of diagnostics and bacteriological researches wound discharge of wound’s discharge are shown. Tactics of complex treatment of patients with prosthetic infection are presented. This work is dedicated to the experimental researchof proliferative activityof the most encountered opportunistic microorganisms found from the patients of vascular surgery profile with purulent septical complications under the influence of bifidobacteriumbifidium’sexometabolites. Presented results proof the submission of proliferative activity of the most widespread antibiotic-resistant hospital’s isolates under the influence of bifidobacteriumbifidium’sexometabolites.Evaluation during the experiment in vitro of the influence of bifidobacteriumbifidium’sexometabolites on proliferative activityof opportunistic microorganisms.

Branched Endovascular Aortic Plug in Patients With Infrarenal Aortic Graft Infection and Hostile Anatomy

Purpose: To present a novel 4-branched endovascular aortic plug (BEVAP) for treatment of patients with infrarenal aortic graft infection. Case Reports: Two polymorbid male patients with aortic graft infections and an unsuturable diseased paravisceral aorta were treated under compassionate use with a custom-made stent-graft. The BEVAP is a factory-modified Zenith t-Branch thoracoabdominal endovascular graft with the distal tubular main graft portion removed, creating an aortic plug that excludes the abdominal aorta while maintaining perfusion to the visceral organs. The BEVAP device is deployed using a femoral approach, and the branches are accessed through an axillary approach. A standard axillobifemoral bypass is created to perfuse the lower body. One to 2 days later, the infected infrarenal graft is resected without the need of aortic clamping or closure of the aortic stump. The BEVAP device in these 2 cases resulted in thrombosis of the abdominal aorta and the infected graft prior to explantation. Conclusion: Using the BEVAP enables radical treatment of selected patients with hostile anatomy and infrarenal aortic graft infections who have an aneurysmal paravisceral aortic segment that prevents traditional radical surgical treatment with in situ reconstruction or extra-anatomical bypass.

Conventional culture diagnostics vs. multiplex PCR for the detection of causative agents of vascular graft infections - results of a single centre observational pilot study

Background: Timely diagnosis of vascular graft infections is of major importance in vascular surgery. The detection of causative microorganisms is needed for specific medical treatment, but conventional culture is often slow, insensitive and inconclusive due to antibiotic pre-treatment. Detection of bacterial DNA by polymerase chain reaction (PCR) might bypass these problems. We hypothesised that multiplex PCR (mPCR) is feasible, fast and sensitive to detect causative microorganisms in vascular graft infections. Patients and methods: We performed a pilot observational prospective study comparing conventional culture and a commercial mPCR. Inclusion criteria were: confirmed graft infection, suspicious imaging, clinical suspicion, anastomotic aneurysm and repeated graft occlusion. Diagnostic methods were performed using identical samples. Time to result, microorganisms and antibiotic resistance in both groups were compared using Student's t-test or nonparametric tests. Results: 22 samples from 13 patients were assessed and 11 samples were negative for bacteria. Some showed multiple germs. In total, we found 15 different organisms. 13 samples matched, 9 had non-concordant results. Out of the mismatches 3 microorganisms identified in PCR were not detected by culture. Time to result with PCR was shorter (median 5 h vs. 72 h, p < 0.001) than with culture. No resistance genes were detected by mPCR, but conventional culture allowed susceptibility testing and revealed resistance in 5 samples. Conclusions: mPCR seems to be a feasible and quick tool to detect causes of vascular graft infections within 24 h and might be helpful in antibiotic pre-treated patients. The detection of antibiotic resistance with mPCR needs improvement for clinical practice.

Psoas abscess associated with aortic endograft infection caused by bacteremia of Listeria monocytogenes: A case report and literature review (CARE Complaint)

RATIONALE

Endograft infection following endovascular stent for aortic aneurysm is rare (0.6%-3%), but it results in high mortality rate of 25% to 88%.

PATIENT CONCERNS

A 66-year-old hypertensive man underwent an endovascular stent graft for abdominal aortic aneurysm 18 months ago. Recurrent episodes of fever, chills, and abdominal fullness occurred 6 months ago before this admission. Laboratory data showed 20 mg/dL of C-reactive protein and abdominal computed tomography (CT) revealed an aortic endoleak at an urban hospital, so 4-day course of intravenous (IV) amoxicillin/clavulanic acid was given and he was discharged after fever subsided. He was admitted to our hospital due to fever, chills, and watery diarrhea for 1 day. Abdominal CT showed left psoas abscess associated with endograft infection. Blood culture grew Listeria monocytogenes.

DIAGNOSIS

Left psoas abscess associated with endograft infection caused by bacteremia of Listeria monocytogenes.

INTERVENTIONS

IV ampicillin with 8 days of synergistic gentamicin was prescribed and it created satisfactory response. Ampicillin was continued for 30 days and then shifted to IV co-trimoxazole for 12 days.

OUTCOMES

He remained asymptomatic with a decline of CRP to 0.36 mg/dL and ESR to 39 mm/h. He was discharged on the 44th hospital day. Orally SMX/TMP was prescribed for 13.5 months.

LESSONS

Only few cases of aortic endograft infection caused by Listeria monocytogenes had been reported. In selected cases, particularly with smoldering presentations and high operative risk, endograft retention with a prolonged antimicrobial therapy seem plausible as an initial therapeutic option, complemented with percutaneous drainage or surgical debridement if necessary.

Comparing Venous Reconstructions and Antimicrobial Graft Reconstructions in Mycotic Abdominal Aortic Aneurysms and Aortic Graft Infections

BACKGROUND

The perioperative mortality and morbidity rates of surgical repair of mycotic abdominal aortic aneurysms and aortic graft infections are high, and the appropriate treatment is debated. This retrospective study compared venous and antimicrobial prosthetic aortic graft reconstructions.

METHODS

All patients of the Northwest Clinics and St. Antonius Hospital who were treated for mycotic abdominal aortic aneurysms or aortic graft infections between January 1, 2008, and January 1, 2018, were analyzed. Exclusion criterion was treatment other than venous or antimicrobial reconstructions. Primary end points were 30-day complications and mortality rates and 3-year overall survival. Secondary end points were reintervention-free survival, persistent infection and reinfection rates, and hospital length of stay.

RESULTS

Fifty-one patients met the inclusion criteria, of whom 32 underwent venous reconstructions and 19 antimicrobial prosthetic aortic graft reconstructions. Baseline characteristics did not differ significantly between these groups, except for duration of surgical repair, which was longer in the venous group. The 30-day and 1-year mortality rates, reinfection rates, complication rates, and hospital length of stay did not significantly differ between the groups. The 3-year overall survival was 77% for venous reconstruction compared with 66% for antimicrobial reconstruction (P = 0.781). The 30-day reintervention rate was 19% for the venous group compared with 42% for the prosthetic group (P = 0.071). Reintervention-free survival at 3 years was 46% for the venous group compared with 52% for the prosthetic group (P = 0.615).

CONCLUSIONS

Venous reconstruction tends to have better 3-year overall survival and lower 30-day reintervention rates compared with antimicrobial prosthetic graft reconstruction in patients with mycotic abdominal aortic aneurysms or abdominal aortic graft infections. In the acute setting, antimicrobial prosthetic graft reconstruction is a valuable solution due to the shorter operation time and similar 30-day mortality and complication rates.

Percutaneous Continuous Irrigation and Drainage for Infected Obturator Bypass Graft

The treatment for obturator bypass graft infection has been rarely reported and is a surgical challenge because it is difficult to debride infected tissue around the graft located in the deep route and to ensure an alternative revascularization route in patients with a history of inguinal infection. Percutaneous continuous irrigation and drainage is an effective and less invasive definitive therapy for obturator bypass graft infection.

Perspective: options in managing aortic graft infections

Thoracic aortic graft infections are infrequent, but are associated with high mortality and morbidity risk. To prevent these life-threatening infections, one must be aware of pathogenesis. When it occurs, a multidisciplinary (surgeon, radiologist, microbiologist, nuclear specialist, infectiologist, anesthesiologist, intensive care specialist) cascade must be initiated. A fast and accurate diagnosis using diagnostic criteria is vital. The appropriate treatment consists of a combination of antibiotics and surgery. Whether or not the vascular prosthesis is preserved depends on a case-by-case basis (tailor-made). Several graft preservation strategies have proven their effectiveness.

A systematic review and meta-analysis of 18F-fluorodeoxyglucose positron emission tomography or positron emission tomography/computed tomography for detection of infected prosthetic vascular grafts

OBJECTIVE

The purpose of this investigation was to evaluate the diagnostic accuracy of ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET) or PET/computed tomography (PET/CT) for the detection of vascular prosthetic graft infection (VPGI) using a diagnostic accuracy test.

METHODS

The MEDLINE/PubMed and Embase databases, from the earliest available date of indexing through March 31, 2018, were searched for results investigating the diagnostic accuracy of ¹⁸F-FDG PET or PET/CT for the detection of VPGI. We calculated the pooled sensitivities and specificities of included studies, calculated positive and negative likelihood ratios, and obtained summary receiver operating characteristic curves.

RESULTS

Across 10 studies (286 patients), the pooled sensitivity was 0.96 (95% confidence interval [CI], 0.89-0.98) without heterogeneity (I² = 40.2; 95% CI, 0.0-84.4; P = .09), and pooled specificity was 0.74 (95% CI, 0.67-0.81) without heterogeneity (I² = 39.9; 95% CI, 0.0-84.3; P = .09). Likelihood ratio syntheses showed an overall positive likelihood ratio of 3.7 (95% CI, 2.9-4.9) and negative likelihood ratio of 0.06 (95% CI, 0.02-0.15). The pooled diagnostic odds ratio was 63 (95% CI, 23-173). The hierarchical summary receiver operating characteristic curve showed the area under the curve to be 0.87 (95% CI, 0.83-0.89).

CONCLUSIONS

This study showed the high sensitivity and moderate specificity of ¹⁸F-FDG PET or PET/CT for the detection of VPGI. The clinical usefulness of ¹⁸F-FDG PET or PET/CT for detection of VPGI should be validated through further large multicenter studies.

Long-term Successful Antibiotic Therapy for Recurrent Aortic Graft Infection

Objective

To report a case of successful long-term conservative management of a patient with aortic graft infection due to multiple infectious agents.

Materials and methods

We describe the clinical case and present a review of relevant literature.

Results

An 82-year-old man presented with recurrent Escherichia coli bacteraemia. He was diagnosed with an endovascular aortic graft infection. As the patient declined surgery, conservative treatment with daily antibiotic therapy was instituted. We report good clinical results after almost 2 years of treatment and follow-up.

Conclusions

The preferred treatment of aortic graft infections is surgical. Conservative management is usually offered to poor surgical candidates and is associated with an unfavourable outcome. However, we report that selected patients may be successfully treated using prolonged antibiotic therapy.

LEARNING POINTS

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.

Complex treatment of vascular prostheses infections

Infections after vascular reconstructions are very rare; however, when they occur, they are associated with a high risk of morbidity. In order to obtain the best results possible, the treatment needs to be initiated as early as possible, from the very first signs of infection, and it needs to be carried out in centers specializing in vascular surgery. The aim of the present study was to assess the incidence of infections in a single university center.This retrospective analysis over a 2-year period is based on the medical reports of hospitalized patients who were diagnosed with infection following revascularization.From 2013 to 2014, a number of 151 open reconstructive surgical procedures were performed. 15 patients suffered from infection (10%) of the vascular reconstruction. Of these patients, 40% have had an aorto-bifemoral bypass, 53%-a femoro-popliteal bypass, and 7% (n = 1)-an axillo-femoral bypass. According to the Samson classification, the patients were categorized as follows: group 2: 6 cases, group 3: 2 cases, group 4: 4 cases, and group 5: 3 cases. The most frequent bacteria found were methicillin-resistant Staphylococcus aureus (MRSA) (n = 6, 40%), followed by S aureus (n = 5, 33%). The treatment options were: application of antibiotics alone without any invasive treatment in 3 patients, local irrigation and debridement in 6 patients, complete explantation of the prosthesis with a new extra-anatomic bypass in 6 cases, and partial excision of the prosthesis, which was replaced and covered with muscle flap, in 3 cases. The amputation rate in our study was 18%, which corresponds to the rates published in the literature.The treatment of infections in vascular surgery needs to be complex and adapted to each individual patient, because infections being in a permanent dynamic state. The treatment needs to be performed in specialized centers that have large experience in vascular surgery, in order for the patient to have the best chances of survival and protection from amputation.

Aortic Graft Infection Secondary to Iatrogenic Transcolonic Graft Malposition

Aortic graft infections are a rare but devastating complication of aortic revascularization. Often infections occur due to contamination at the time of surgery. Iatrogenic misplacement of the limbs of an aortobifemoral graft is exceedingly rare, and principles of evaluation and treatment are not well defined. We report 2 cases of aortobifemoral bypass graft malposition through the colon.

CASE REPORT

Case 1 is a 54-year-old male who underwent aortobifemoral bypass grafting for acute limb ischemia. He had previously undergone a partial sigmoid colectomy for diverticulitis. Approximately 6 months after vascular surgery, he presented with an occult graft infection. Preoperative imaging and intraoperative findings were consistent with graft placement through the sigmoid colon. Case 2 is a 60-year-old male who underwent aortobifemoral bypass grafting due to a nonhealing wound after toe amputation. His postoperative course was complicated by pneumonia, bacteremia thought to be secondary to the pneumonia, general malaise, and persistent fevers. Approximately 10 weeks after the vascular surgery, he presented with imaging and intraoperative findings of graft malposition through the cecum.

CONCLUSIONS

Aortic graft infection is usually caused by surgical contamination and presents as an indolent infection. Case 1 presented as such; Case 2 presented more acutely. Both grafts were iatrogenically misplaced through the colon at the index operation. The patients underwent extra-anatomic bypass and graft explantation and subsequently recovered.

Contribution of sonicate-fluid cultures and broad-range PCR to microbiological diagnosis in vascular graft infections

BACKGROUND

Vascular graft infections (VGI) are associated with considerable morbidity and mortality, and antimicrobial treatment is an important adjunct to surgical treatment. While microbial aetiology of VGI is often difficult to determine, other techniques such as sonication of implanted material may be used to enhance the recovery of biofilm-associated organisms.

METHODS

We performed a retrospective analysis of 22 consecutive patients treated for VGI at University Medical Centre Ljubljana from May 2011 through January 2015. Explanted vascular grafts were flooded with sterile Ringer solution, sonicated for 1 min at a frequency of 40 kHz and inoculated on solid and liquid culture media. Aerobic and anaerobic cultures were performed, incubated for 14 days and any significant bacterial growth was quantitatively evaluated. Additionally, broad-range PCR from sonicate fluid was performed. Microbiological results were compared with the results of preoperatively taken blood cultures and the results of intraoperative tissue cultures (material from peri-graft collection).

RESULTS

Identification of the causative organism (irrespective of the method) was achieved in 95.8%. Preoperative blood cultures were positive in 35.3%, intraoperative tissue cultures in 31.8%, sonicate fluid culture in 79.2%, while broad-range PCR from sonicate fluid was positive in 66.7%. In 37.5% the pathogen detected in sonicate fluid culture or broad-range PCR was the only positive microbiological result.

CONCLUSIONS

Sonicate fluid culture and broad-range PCR from explanted vascular grafts may contribute to optimization of antimicrobial treatment. Optimal timing of antibiotic therapy before explantation should be further assessed to improve diagnostic yield.

Systemic thioridazine in combination with dicloxacillin against early aortic graft infections caused by Staphylococcus aureus in a porcine model: In vivo results do not reproduce the in vitro synergistic activity

Introduction

Conservative treatment solutions against aortic prosthetic vascular graft infection (APVGI) for inoperable patients are limited. The combination of antibiotics with antibacterial helper compounds, such as the neuroleptic drug thioridazine (TDZ), should be explored.

Aim

To investigate the efficacy of conservative systemic treatment with dicloxacillin (DCX) in combination with TDZ (DCX+TDZ), compared to DCX alone, against early APVGI caused by methicillin-sensitive Staphylococcus aureus (MSSA) in a porcine model.

Methods

The synergism of DCX+TDZ against MSSA was initially assessed in vitro by viability assay. Thereafter, thirty-two pigs had polyester grafts implanted in the infrarenal aorta, followed by inoculation with 10⁶ CFU of MSSA, and were randomly administered oral systemic treatment with either 1) DCX or 2) DCX+TDZ. Treatment was initiated one week postoperatively and continued for a further 21 days. Weight, temperature, and blood samples were collected at predefined intervals. By termination, bacterial quantities from the graft surface, graft material, and perigraft tissue were obtained.

Results

Despite in vitro synergism, the porcine experiment revealed no statistical differences for bacteriological endpoints between the two treatment groups, and none of the treatments eradicated the APVGI. Accordingly, the mixed model analyses of weight, temperature, and blood samples revealed no statistical differences.

Conclusion

Conservative systemic treatment with DCX+TDZ did not reproduce in vitro results against APVGI caused by MSSA in this porcine model. However, unexpected severe adverse effects related to the planned dose of TDZ required a considerable reduction to the administered dose of TDZ, which may have compromised the results.

Graft infection after a Bentall procedure: A case series and systematic review of the literature

INTRODUCTION

The Bentall procedure is a cardiac surgery involving graft replacement of the aortic valve, aortic root and ascending aorta. Graft infection after Bentall's procedure (BGI) is infrequent but severe, and often difficult to diagnose and treat.

PATIENTS AND METHODS

A retrospective cohort study was performed using the Bordeaux endocarditis database of adult patients admitted to the Bordeaux University Medical Hospital for BGI between 2008 and 2014. Published case reports were identified in the literature.

RESULTS

We identified 10 BGI patients in the database and 13 in the literature. The majority of infections were late-onset (20/23) and occurred as a result of gram positive cocci bacterial infection (16/22). Detailed diagnoses of the described BGI were determined using echocardiography, computed tomography (CT) and positron emission tomography/CT (PET/CT). Labeled-leukocyte scintigraphy was not reported in any case. Prolonged antibiotic therapy and surgery were found to be the treatment of choice for BGI; however it was not always possible to perform a surgical intervention. Clinical relapses occurred even with a negative PET/CT, while PET/CT consistently positive for BGI occurred in the absence of clinical relapse. This suggests that the use of PET/CT for follow-up is questionable.

CONCLUSION

Diagnosis of BGI is difficult, due to the combination of clinical, biological, and radiological observations obtained through transesophageal echocardiography and CT. PET/CT is an alternative method to diagnosis BGI, but its impact on clinical management remains unclear. Current data suggests that if surgical replacement of the prosthesis is not possible, patients should be treated with prolonged antibiotic therapy.

Aortic Graft Infections after Emergency and Non-Emergency Reconstruction: Incidence, Treatment, and Long-Term Outcome

BACKGROUND

Aortic graft infections (AGI) are rare, with an incidence of 0.6%-3% among patients with aortic grafts. Most previous reports are based on single-center material with limited follow-up. Because of the paucity of these cases, the optimal treatment remains unclear. A factor possibly affecting the mortality rate of these infections is whether the index procedure was emergency or elective. The aim of this study was to investigate the incidence of AGI and assess the long-term outcome after emergency and non-emergency aortic reconstruction in a large population.

METHOD

A population-based, retrospective study was conducted of all patients treated with aortic reconstructive surgery at the two centers for vascular surgery in Stockholm County (population 2.2 million) during 2005-2015. Patients with AGI were identified by the in-hospital patient registry. Chart data on demographics, co-morbidity, index operation, type of infection, treatment, and outcome were analyzed.

RESULTS

Reconstructive aortic surgery was performed on 2,026 patients (open repair 47.7%; endovascular aortic repair 52.3%). The incidence of infection was 1.4% (29/2,026). The index operation was performed as an emergency in ten patients and non-emergency in 19. Median follow-up after the index operation was 69.2 months (interquartile range [IQR] 109.5). Patients having an emergency index procedure were older (77 vs. 69 y; p = 0.03). Time to infection was similar (30.2 ± 27.4 and 56.1 ± 51.2 mos; p = 0.21). The median time from diagnosis of AGI to surgery was 30 d (IQR 30.5 d). Infectious agents were identified in 76% of the cases. Of the conservatively treated patients, one was free of infection compared with three of the surgically treated. Conservatively treated patients had a higher graft-associated mortality rate of 57% compared with 25% of the surgically treated (p = 0.05).

CONCLUSIONS

This population-based study with long-term follow-up confirms the low incidence of AGI, 1.4%. The similar incidence in the emergency and non-emergency groups suggests that the index operation is not decisive in the development of AGI. The outcome of these infections generally is poor but is worse for non-surgically treated patients.

Textural features of 18F-fluorodeoxyglucose positron emission tomography scanning in diagnosing aortic prosthetic graft infection

BACKGROUND

The clinical problem in suspected aortoiliac graft infection (AGI) is to obtain proof of infection. Although ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography scanning (PET) has been suggested to play a pivotal role, an evidence-based interpretation is lacking. The objective of this retrospective study was to examine the feasibility and utility of ¹⁸F-FDG uptake heterogeneity characterized by textural features to diagnose AGI.

METHODS

Thirty patients with a history of aortic graft reconstruction who underwent ¹⁸F-FDG PET/CT scanning were included. Sixteen patients were suspected to have an AGI (group I). AGI was considered proven only in the case of a positive bacterial culture. Positive cultures were found in 10 of the 16 patients (group Ia), and in the other six patients, cultures remained negative (group Ib). A control group was formed of 14 patients undergoing ¹⁸F-FDG PET for other reasons (group II). PET images were assessed using conventional maximal standardized uptake value (SUVmax), tissue-to-background ratio (TBR), and visual grading scale (VGS). Additionally, 64 different ¹⁸F-FDG PET based textural features were applied to characterize ¹⁸F-FDG uptake heterogeneity. To select candidate predictors, univariable logistic regression analysis was performed (α = 0.16). The accuracy was satisfactory in case of an AUC > 0.8.

RESULTS

The feature selection process yielded the textural features named variance (AUC = 0.88), high grey level zone emphasis (AUC = 0.87), small zone low grey level emphasis (AUC = 0.80), and small zone high grey level emphasis (AUC = 0.81) most optimal for distinguishing between groups I and II. SUVmax, TBR, and VGS were also able to distinguish between these groups with AUCs of 0.87, 0.78, and 0.90, respectively. The textural feature named short run high grey level emphasis was able to distinguish group Ia from Ib (AUC = 0.83), while for the same task the TBR and VGS were not found to be predictive. SUVmax was found predictive in distinguishing these groups, but showed an unsatisfactory accuracy (AUC = 0.75).

CONCLUSION

Textural analysis to characterize ¹⁸F-FDG uptake heterogeneity is feasible and shows promising results in diagnosing AGI, but requires additional external validation and refinement before it can be implemented in the clinical decision-making process.

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.

A novel method for long-lasting preservation of arterial grafts

BACKGROUND

Autologous venous grafts generally give best results for arterial bypass grafting in cases of arterial stenosis. When no suitable venous graft can be found, synthetic prosthetic graft may be an alternative. Prostheses are easily accessible but susceptible to infection. In these cases, the replacement of infected prosthesis by the human arterial allograft is the best treatment option. The question arises whether we could prepare a graft meeting mechanical conditions of an artery immunologically inert and resistant to bacterial infection.

MATERIALS AND METHODS

LEW and BN rat aortic segments were placed in dehydrated sodium chloride and stored for 1 to 12 mo. Then, they were transplanted orthotopically as aortic grafts for 3 to 15 mo in syngenic and allogenic combination. No immunosuppression was used. Patency, pulsation, and frequency of development of aneurysms were studied. The tensile strength and maximum intraluminal pressures were measured. Morphology of grafts was evaluated on histology and electron microscopy. The endothelial and infiltrating cells were identified.

RESULTS

Transplanted allogeneic aortic grafts preserved in anhydrous sodium chloride up to 12 mo remained patent for 15 mo. Hypertrophy of intima with endothelial cells lining the inner surface and single muscle cells between elastic fibers were seen. Normal structure of collagen and elastic fibers was maintained. Only minor-host mononuclear infiltrates were seen around the preserved allografts.

CONCLUSIONS

Rat aortas preserved in anhydrous sodium chloride retain patency and function even 15 mo after transplantation. Such grafts retain their wall structure and evoke only minor recipient reaction. Our results confirm that anhydrous sodium chloride may be used for arterial grafts preservation. Low immunogenicity is additional advantage.

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.