Intra-abdominal aortic graft infection: prognostic factors associated with in-hospital mortality

Characteristics and Outcome of Vascular Graft Infections: A Risk Factor and Survival Analysis

Background

Vascular graft infection (VGI) is a serious complication after implantation of arterial vascular grafts. Optimal surgical and pathogen-specific antimicrobial treatment regimens for VGI are largely unknown. We evaluated patients with arterial VGI according to onset, location, microbiological and imaging characteristics, and surgical and antimicrobial treatment and performed an outcome evaluation.

Methods

Consecutive patients with VGI treated in 2 hospitals from 2010 through 2020 were retrospectively analyzed. Uniform definition criteria and standardized outcome evaluation were applied. Logistic regression was used for multiple analysis; survival analysis was performed with Kaplan-Meier analysis and a log-rank test.

Results

Seventy-eight patients with VGI were included: 30 early-onset cases (<8 weeks after graft implantation) and 48 late-onset cases, involving 49 aortic and 29 peripheral grafts. The median time from initial implantation to diagnosis of VGI was significantly longer in aortic than peripheral VGIs (363 vs 56 days, P = .018). Late-onset VGI (odds ratio [OR], 7.3; P = .005) and the presence of surgical site infection/complication (OR, 8.21; P = .006) were independent risk factors for treatment failure. Surgical site infection/complication was associated with a higher risk for early-onset VGI (OR, 3.13; P = .040). Longer infection-free survival was observed in cases where the infected graft was surgically removed (P = .037).

Conclusions

This study underlines the importance of timely diagnosis of VGI and preventing surgical site infections/complications at graft implantation. It highlights the complexity of infection eradication, especially for late-onset infections, and the importance of adequate antimicrobial and surgical treatment.

Outcomes Following Use of Bovine Pericardium (Xenoprosthetic) Grafts for Reconstruction of Mycotic Aortic Aneurysms and Infected Aortic Grafts: A Systematic Review and Meta-Analysis

BACKGROUND

Infected aortic grafts and mycotic aneurysms represent one of the most complex challenges faced by vascular surgeons. Treatment has progressed from extra-anatomical bypass to in situ reconstruction. Additionally, bovine pericardium reconstruction (BPR) has increased, due to accessibility and reduced lower limb morbidity. There remains, however, limited evidence for its use. The aim is to pool all known data to understand outcomes following BPR of mycotic aneurysms or infected vascular grafts.

METHODS

A systematic review was conducted in November 2021 with subsequent computerized meta-analysis of the pooled results and a final search in March 2022. Three databases, Excerpta Medica dataBASE (EMBASE), Cumulative Index of Nursing and Allied Health Literature (CINAHL), and National Institutes of Health PubMed (PubMed), were searched for the search term "(bovine OR xenoprosthetic) AND (aneurysm)", according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

RESULTS

From 9 studies, there were 133 patients: 67% graft infections and 33% mycotic aneurysms. Fifty-seven percent of reconstructions were in the abdominal aorta and 33% were in the thoracic aorta. One hundred fifty-eight pathogens were identified, including Staphylococcus aureus (23%), Candida albicans (13%), and Escherichia coli (13%). In 12%, no microorganisms were identified. Thirty-day mortality was 19.14% (CI 10.83-28.71), late mortality was 19.08% (confidence interval [CI] 7.76-32.83), and overall mortality was 40.20% (CI 29.82-50.97). One patient died intraoperatively. There were a total of 151 in-hospital complications after 30 days postoperation. Common complications were acute renal failure (17%), pneumonia (14%), delirium (12%), respiratory insufficiency (11%) and renal insufficiency (7%). Lower limb ischemia was low, occurring in 5.66% (CI 0.54-13.82) of patients. Loss of graft patency leading to reintervention occurred in 1.20% (CI 0.00-7.71) of the grafts. Reinfection rate was 0.00% (CI 0.00-1.21).

CONCLUSIONS

This meta-analysis highlights low reinfection and high graft patency using BPR with medium-length follow-up; however, there remain limited long-term and comparative data regarding options for aortic reconstruction. As expected in this complex cohort, the complication rate and 30-day mortality remain high.

Nonspecific Presentation of an Infected Aorto-Iliac Artery Stent Following Endovascular Revision and Stent Insertion

Over the last few decades, the use of covered stent grafts became increasingly popular; as it plays a pivotal role in the management of various atherosclerotic diseases that are rising in both incidence and prevalence. Subsequently, vascular stent infections, although rare, are becoming a well-recognized complication with possibly devastating consequences, owing to the difficulties associated with its diagnosis and treatment. This has prompted significant interest in the condition regarding its pathophysiology, modifiable and non-modifiable risk factors, diagnostic and therapeutic approaches, and the possible implementation of prophylactic measures. We herein present a case of a patient with an infected aortoiliac stent 4 weeks after endovascular revision with atherectomy and additional stent insertion. The patient initially developed nonspecific symptoms and later developed a life-threatening hemorrhage, which was urgently controlled using a percutaneously inserted covered stent at the infected site. Definitive treatment using extraanatomical bypass implantation and an explantation of the infected stents was performed with excellent clinical response.

Cryopreserved arterial allografts vs rifampin-soaked Dacron for the treatment of infected aortic and iliac grafts

OBJECTIVE

Aortic and iliac graft infections remain complex clinical problems with high mortality and morbidity. Cryopreserved arterial allografts (CAAs) and rifampin-soaked Dacron (RSD) are options for in situ reconstruction. This study aimed to compare the safety and effectiveness of CAA vs RSD in this setting.

METHODS

Data from patients with aortic and iliac graft infections undergoing in situ reconstruction with either CAA or RSD from January 2002 through August 2022 were retrospectively analyzed. Our primary outcomes were freedom from graft-related reintervention and freedom from reinfection. Secondary outcomes included comparing trends in the use of CAA and RSD at our institution, overall survival, perioperative mortality, and major morbidity.

RESULTS

A total of 149 patients (80 RSD, 69 CAA) with a mean age of 68.9 and 69.1 years, respectively, were included. Endovascular stent grafts were infected in 60 patients (41 CAA group and 19 RSD group; P ≤ .01). Graft-enteric fistulas were more common in the RSD group (48.8% RSD vs 29.0% CAA; P ≤ .01). Management included complete resection of the infected graft (85.5% CAA vs 57.5% RSD; P ≤ .01) and aortic reconstructions were covered in omentum in 57 (87.7%) and 63 (84.0%) patients in the CAA and RSD group, respectively (P = .55). Thirty-day/in-hospital mortality was similar between the groups (7.5% RSD vs 7.2% CAA; P = 1.00). One early graft-related death occurred on postoperative day 4 due to CAA rupture and hemorrhagic shock. Median follow-up was 20.5 and 21.5 months in the CAA and RSD groups, respectively. Overall post-discharge survival at 5 years was similar, at 59.2% in the RSD group and 59.0% in the CAA group (P = .80). Freedom from graft-related reintervention at 1 and 5 years was 81.3% and 66.2% (CAA) vs 95.6% and 92.5% (RSD; P = .02). Indications for reintervention in the CAA group included stenosis (n = 5), pseudoaneurysm (n = 2), reinfection (n = 2), occlusion (n = 2), rupture (n = 1), and graft-limb kinking (n = 1). In the RSD group, indications included reinfection (n = 3), occlusion (n = 1), endoleak (n = 1), omental coverage (n = 1), and rupture (n = 1). Freedom from reinfection at 1 and 5 years was 98.3% and 94.9% (CAA) vs 92.5% and 87.2% (RSD; P = .11). Two (2.9%) and three patients (3.8%) in the CAA and RSD group, respectively, required graft explantation due to reinfection.

CONCLUSIONS

Aorto-iliac graft infections can be managed safely with either CAA or RSD in selected patients for in situ reconstruction. However, reintervention was more common with CAA use. Freedom from reinfection rates in the RSD group was lower, but this was not statistically significant. Conduit choice is associated with long-term surveillance needs and reinterventions.

Management and Outcome of Non-Aneurysmal Primary Aortic Infection

INTRODUCTION

Aortic infection without prior intervention or aneurysm is exceedingly rare. We report the presentation, diagnosis, management, and outcome of patients with this unusual entity.

METHODS

Retrospective chart and imaging review of patients with primary aortic infection.

RESULTS

5 patients (3 male, mean age 71.2 years) presented between 2014 and 2022. All had abdominal, back, or flank pain. Four had constitutional symptoms. All were evaluated with a complete blood count; 3 had leukocytosis. Both serum C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) were elevated in the 4 patients evaluated with these tests. All were studied with peripheral blood culture on the first hospital day prior to any antibiotic administration. Blood culture was positive in only 1 patient. Computed tomography (CT) scan showed periaortic inflammation without aneurysm in all. Fluorodeoxyglucose positron emission tomography (PET) was obtained in 3 and a radiolabeled leukocyte single-photon emission CT (SPECT) scan was performed in 2. All demonstrated periaortic concentration of the radioisotope consistent with inflammation or infection. Intraoperative cultures were positive in 3. One patient who had a negative intraoperative culture was examined with broad range polymerase chain reaction (PCR) and DNA sequencing which identified a causative bacterium. The other patient with a negative intraoperative culture had periaortic abscess but was on antibiotics preoperatively, potentially confounding the culture. All patients underwent in-situ repair with rifampin impregnated polyester (N = 2), cryopreserved aortic allograft (N = 2), or autogenous femoral vein (N = 1). No patient developed recurrent infection or aortic related complications following surgery with an average follow up of 31.8 months (range 8-88 months).

CONCLUSIONS

Patients with primary aortic infection present similarly with the triad of abdominal or back pain, laboratory markers of infection, and imaging demonstrating periaortic inflammation. Patients were treated successfully with in-situ repair. Preoperative identification of a causative organism was difficult, and PCR may be useful to help identify an organism.

Outcomes of Candida and Non-Candida Aortic Graft Infection

OBJECTIVE

To evaluate and compare the outcomes of Candida- and non-Candida-associated aortic graft infections.

METHODS

We retrospectively analyzed the data from patients treated for aortic graft infection from 2015 to 2021 in our hospital.

RESULTS

A total of 66 patients (56 men; median age, 69 years; range, 50-87 years) were admitted with aortic graft infection, including 21 (32%) patients in the Candida group and 45 (68%) in the non-Candida group. The average time between initial operation and presentation of aortic graft infection was 50 months (range, 1-332 months). Graft-enteric fistulas (GEFs) were more often in the Candida group (57% vs 27%, P = .017). The most proven causative fungal specimen was C. albicans in 16 (76%) patients. Non-albicans Candida was found in 9% of all patients and 29% of the Candida patients. The median ICU length of stay was longer in the Candida group than non-Candida (10 vs 9 days, P = .012). Additionally, the median hospital length of stay was longer in the Candida group (33 vs 22 days, P = .048). There were no statistically significant differences between Candida and non-Candida groups according to the in-hospital mortality (24% vs 24%, P = .955), and 1-year mortality (38% vs 38%, P = .980).

CONCLUSIONS

Patients with bacterial and fungal aortic graft infections have high rates of morbidity and mortality. We found no significant differences in postoperative morbidity and mortality between Candida and non-Candida patients. However, the ICU and hospital length of stay were longer in the Candida group.

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.

Predictive Factors for Aortic Graft Infection: A Case-Control Study

BACKGROUND

Graft infections are one of the most serious complications in vascular surgery, with high mortality rates. Few studies addressed risk factors associated with a higher susceptibility to infection. The aim of this study is to identify perioperative factors associated with aortic graft infections (AGI).

METHODS

We designed a retrospective, case-control study from patients subjected to open aortic repair between 2013 and 2019. Cases of AGI were defined according to the management of aortic graft infection collaboration (MAGIC) criteria and matched to controls without proven infection. Demographics, hospital complications, and laboratory workups were assessed. Predictors of AGI were identified through univariate and multivariate analysis.

RESULTS

Most graft infections occurred in a late period (n = 17; 85%), after a median interval of 13.5 months interquartile range (IQR 1.5-36). Gram-negative bacteria were most frequently isolated in infected grafts, namely Enterobacteriaceae (n = 12). Cases had significantly lower postoperative serum albumin levels (1.9 g/dL vs. 2.4 g/dL; P = 0.002). Alcohol abuse, malignancy, prolonged lengths of stay, wound infection and dehiscence, in-hospital infection, postoperative heart failure or bowel ischemia were significantly correlated to the onset of AGI. In the multivariate analysis, prolonged hospital stays odds ratio (OR 1.05; P = 0.03), malignancy (OR 5.82; P = 0.03) and alcohol abuse (OR 42.41; P = 0.002) maintained a significant association.

CONCLUSIONS

The risk of AGI seems to be higher in patients with concurrent malignancy, alcohol abuse or prolonged hospital stays. Strategies to mitigate this complication in these patients are of utmost importance.

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.

Dependent functional status rather than age is a better predictor of adverse outcomes after excision of an infected abdominal aortic graft

OBJECTIVE

The optimal management of infected abdominal aortic grafts is complete surgical excision plus in situ or extra-anatomic revascularization in patients who can tolerate this morbid operation. In addition to using age and the presence of comorbidities for risk assessment, physicians form a global clinical impression when deciding whether to offer excision or to manage conservatively. Functional status is a distinct objective measure that can inform this decision. This study examines the relative impact of age and functional status on outcomes of infected abdominal aortic graft excision to guide surgical decision-making.

METHODS

Current Procedural Terminology code 35907 was used to identify patients undergoing excision of infected abdominal aortic graft in the 2005 to 2017 American College of Surgeons - National Surgical Quality Improvement Program (NSQIP) database. Patients were stratified by the upper age quartile (75 years old) as a cutoff, and then by functional status, independent vs dependent (as defined by NSIQIP). The patients were then stratified into four groups: Younger (<75)/Independent, Younger (<75)/Dependent, Older (≥75)/Independent, and Older (≥75)/Dependent. Outcomes measured included 30-day mortality and major organ-system dysfunction.

RESULTS

There were 814 patients who underwent infected abdominal aortic graft excision: 508 patients (62%) were Younger/Independent, 89 patients (11%) were Younger/Dependent, 176 patients (22%) were Older/Independent, and 41 patients (5%) were Older/Dependent. There was no statistically significant difference in 30-day mortality for Younger/Dependent (odds ratio [OR], 1.66; 95% confidence interval [CI], 0.90-3.09; P = .536) or Older/Independent (OR, 1.31; 95% CI, 0.78-2.19; P = .311) patients when compared with Younger/Independent patients, which suggests that neither old age nor dependent functional status by itself adversely affects mortality. However, when both factors were present, Older/Dependent patients had three times higher mortality when compared with Younger/Independent patients (41.5% vs 13.4%, respectively; OR, 3.13; 95% CI, 1.46-6.71; P = .003). Furthermore, as long as patients presented with independent functional status, old age by itself did not adversely affect major organ-system dysfunction (ORs for Older/Independent vs Younger/Independent were 0.76 [P = .454], 1.04 [P = .874], and 0.90 [P = .692] for cardiac, pulmonary, and renal complications, respectively). On the contrary, even in younger patients, dependent functional status was significantly associated with higher pulmonary complications (Younger/Dependent vs Younger/Independent: OR, 2.22; 95% CI, 1.33-3.73; P = .002) and higher rates of unplanned reoperation (OR, 2.67; 95% CI, 1.62-4.41; P < .0001).

CONCLUSIONS

Dependent functional status has significant association with adverse outcomes after excision of infected abdominal aortic grafts, whereas old age alone does not. Therefore, this procedure could be considered in appropriately selected elderly patients with otherwise good functional status. However, caution should be applied in dependent patients regardless of age due to the risk of pulmonary complications.

Treatment and Outcomes of Aortic Graft Infections Using a Decision Algorithm

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Short and Mid Term Outcomes of Cryopreserved Abdominal Aortic Allografts Used as a Substitute for Infected Prosthetic Grafts in 200 Patients

OBJECTIVE

To investigate the use of cryopreserved arterial allografts (CAA) as a substitute for infected infrarenal aortic prostheses, and its outcomes.

METHODS

A single centre retrospective study of consecutive patients receiving an abdominal aortic CAA after removal of an infected graft was conducted between January 1997 and December 2013. The primary outcome was the rate of allograft related revision surgery. Secondary outcomes were the 30 day mortality rate, survival, primary patency, limb salvage, and infection recurrence. Allograft ruptures secondary to infection and risk factors for allograft failure were also investigated.

RESULTS

Two hundred patients (mean age 64.2 ± 9.4 years) were included. In 56 (28%) cases, infection was related to an enteric fistula. The mean follow up duration was 4.1 years. The 30 day mortality rate was 11%. Early revision surgery was needed in 59 patients (29.5%). Among them, 15 (7.5%) were allograft related and led to the death of three patients (1.5%), corresponding to a 7.5% 30 day allograft related revision surgery rate. During the first six months, 17 (8.5%) patients experienced 21 events with complete or partial rupture (pseudo-aneurysm) of the allograft responsible for five (2.5%) deaths, corresponding to a re-infection rate of 8.5%. The multivariable analysis showed that diabetes and pseudo-aneurysm of the native aorta on presentation were predictive factors for short term allograft rupture. After six months, 25 (12.5%) patients experienced long term allograft complications (rupture, n = 2, 1%; pseudo-aneurysm, n = 6, 3%; aneurysm, n = 2, 1%; thrombosis, n = 11, 5.5%; stenosis, n = 4, 2%;) requiring revision surgery resulting in one death. The five year rates of survival, allograft related revision surgery, limb salvage, primary patency, and infection recurrence were 56%, 30%, 89%, 80%, and 12%, respectively.

CONCLUSION

CAAs provide acceptable results to treat aortic graft infection with few early graft related fatal complications. Long term allograft related complications are quite common but are associated with low mortality and amputation rates.

Aortic Prosthesis-Associated MDR Pseudomonas Infections as a Diagnostic and Therapeutic Challenge

Endovascular prostheses are used to treat life-threatening conditions such as ruptured aortic aneurysms. Prosthetic infection cause significant morbidity and mortality, posing important diagnostic and therapeutic challenges. It is particularly difficult to diagnose and, in the era of multidrug resistance (MDR), these type of infections may become even more difficult to treat. Herein, we reported a case of a secondary prosthetic endovascular infection following repeated bacteremia episodes from a urinary source. This case illustrates an MDR Pseudomonas aeruginosa aortic infection that was difficult to diagnose with no oral antibiotic treatment options.

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.

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.

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.

Twenty-year experience with cryopreserved arterial allografts for vascular infections

OBJECTIVES

The aim of this study was to analyse outcomes over 2 decades using cryopreserved vascular allografts to treat vascular infection.

METHODS

We conducted a retrospective study of patients identified from our institutional database who were treated for primary or secondary vascular infection using implanted allografts.

RESULTS

Between October 1992 and May 2014, 54 patients underwent surgery for vascular infection out of 118 patients implanted with cryopreserved vascular allografts. The 52 patients for whom we had full information form the basis of the study with a 96% follow-up. The average age was 64 ± 11 years; 87% were men; 65% had previous vascular surgery; 19% had emergency operations. A total of 75% of the patients had aortoiliofemoral infections. Five patients underwent surgery with cardiopulmonary bypass. Fifty percent required more than 1 allograft and 15% had concomitant procedures. Seventy-three percent (38/52) of specimen cultures yielded positive results with polymicrobial flora in 29%. Surgical specimens most frequently grew coagulase-negative staphylococci. The early postoperative reoperation rate was 15% for allograft-related complications. There were 20 (38%) early deaths, including deaths of acute myocardial infarction, anastomosis rupture and persistent sepsis and shock. Uncontrolled infection leading to septic shock and multiple organ failure was the cause of death in 50% of the cases. The mean duration of freedom from allograft reintervention was 12.2 years. The mean duration of freedom from allograft occlusion or limb loss was 12.1 years [95% confidence interval (CI) 9.9-14.4]. Of the 32 surviving patients, we had patency information for 66% obtained by angiography or computed tomography. The mean survival for the cohort was 5.9 years (95% CI 3.9-7.8). Mean freedom from cardiovascular infection-related death was 9.3 years (95% CI 7.2-11.4).

CONCLUSIONS

Allografts can be indicated for treatment of primary/secondary infection and have remarkable results in multimorbid patients. Patients with vascular infection have a high-risk profile, around 40% mortality during the first 6 months, with reduction in overall mortality thereafter. We believe that allografts may play a role in the surgical treatment of vascular infection.

Abdominal Aortic Graft Infection Caused by stG485.0, ST29 Streptococcus dysgalactiae subsp. equisimilis

In recent years, the prevalence of invasive Streptococcus dysgalactiae subsp. equisimilis (SDSE) infections has increased gradually throughout the world, including Japan. Here, we report the case of an abdominal aortic graft infection caused by stG485.0, ST29 SDSE in an elderly patient with diabetes. The patient was an 86-year-old man who had undergone surgery 10 years ago for treating a non-infected abdominal aortic aneurysm using a bifurcated graft. He was referred to our hospital after being suspected of having an abdominal aortic graft infection based on computed tomography (CT) scans. He underwent surgery to drain the pus that had accumulated between the aneurysm and graft. Although blood cultures were negative, the surgical specimen culture was positive for a β-hemolytic group G streptococci, which was subsequently identified as SDSE using 16S ribosomal RNA sequencing. Genetic relationships deduced from emm and multilocus sequence typing revealed the isolate to be types stG485.0 and ST29, respectively. Although aortic aneurysm graft infection has a poor prognosis, we successfully rescued the patient through prompt surgery and identification of the responsible pathogen. This case indicates that attention must be paid toward possible SDSE infections in the field of vascular surgery.

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.

Replacement of infected aortoiliac vascular grafts with bifurcated BioIntegral Surgical No-React® bovine pericardial xenografts

The infection of a vascular prosthesis is potentially fatal, and its effective treatment still remains the greatest challenge for vascular surgeons. We present our initial experience using bovine pericardial vascular prostheses to replace infected aortoiliac vascular grafts. Six consecutive patients with infection of the graft were prospectively included in this study. Infection of the vascular graft was confirmed by clinical symptoms, laboratory tests and the results of computed tomography and positron emission tomography/computed tomography. In all cases, the infected aortoiliac graft was surgically removed and replaced by the bovine-pericardial BioIntegral aortic-bifemoral prosthesis. Technical success was achieved in every case with no in-hospital or 30 days mortality. One patient required revision of distal anastomosis due to recurrent bleeding at day four after surgery. One patient presented with upper gastrointestinal tract bleeding during the postoperative period, which was managed endoscopically. The mean hospital stay was 14 days (range 9-19). The control CT scan performed 2 months after surgery showed significant regression of abscesses and periprosthetic inflammation. Two patients died within 32 months of follow-up: one due to heart attack, the other due to generalized sepsis, which was correlated with the previous infection. Four patients are still in follow-up. The BioIntegral prosthesis is patent in all four cases, with no clinical or ultrasonographic signs of infection. Our brief investigation shows that a bovine pericardial prosthesis may be a valuable option in the treatment of vascular grafts infections.

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

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.

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.

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.

An axillofemoral bypass graft transgressing the chest wall

Explantation of an infected patent vascular graft does not necessarily require concomitant revascularization procedures. The need for revascularization can be determined by a trial cross‐clamping of the graft and clinical assessment of limb perfusion. We report a case of an infected axillofemoral graft transgressing the chest wall in a surgically high risk patient.

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.

[Complications following aortic reconstruction surgery]

BACKGROUND

The potential complications following aortic reconstruction surgery are diverse and potentially life-threatening. Besides the well known complications of open aortic repair (OAR) the spectrum of complications has been extended and shifted by the growing use of endovascular aortic repair (EVAR).

AIM

The most common complications of open as well as endovascular aortic surgery are presented in a summarizing review. The focus is placed on the presentation of cardiovascular and nephrological complications, colonic ischemia, as well as aortic graft infections and graft fistulas. Spinal ischemia and endoleaks after EVAR are also discussed. Additionally epidemiological data, risk factors and basic therapeutic principles are outlined.

CONCLUSION

Aortic reconstruction surgery can be associated with severe complications, the main features of which should be known by all surgical specialties.

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.