An ex vivo study of infections of vascular grafts and endografts with scanning electron microscopy.

OBJECTIVE: Vascular graft and endograft infections (VGEIs) are complicated by high morbidity, mortality, and recurrence rates, notably due to biofilm formation on the graft surface, hardly dislodgeable by the sole anti-infectious treatment. The characteristics of this biofilm are still poorly documented. The aim of this study was to evaluate ex vivo biofilm on removed infected vascular grafts and endografts (VGEs). METHODS: Explanted VGEs were prospectively collected from 2019 to 2022 at Bordeaux University Hospital, France. Two samples per graft were used for scanning electron microscopy imaging; one was sonicated, and both grafts' sides were imaged. RESULTS: A total of 26 patients were included, 18 with VGEI, eight without any infection (endoleak and/or thrombosis), and 29 VGEs were collected. Microbial documentation was obtained in 83% of VGEIs. A thick layer of fibrin was visible on almost all grafts, mixed with a dense biofilm matrix on infected grafts visible as early as 1 month after the onset of infection. Bacteria were not always visualized on infected grafts' surface (80% on outer side and 85% on luminal side) but were surprisingly present on one-third of non-infected grafts. There was no significant difference between biofilm, fibrin, and microorganisms' distribution between the two grafts' sides. However, there were clear differences between infected and non-infected grafts, since immune cells, bacteria and biofilm were more frequently visualized on both sides of infected grafts (P < .05). Bacteria and immune cells although still visible, were significantly less present after sonication; the number of other elements including biofilm was not significantly different. CONCLUSIONS: The persistence of a thick layer of fibrin and biofilm embedding microorganisms on both sides of infected VGE even after 1 month of infection could be the explanation for the low success rates of conservative management and the usual need for graft removal to treat VGEIs.

Editor's Choice -- European Society for Vascular Surgery (ESVS) 2024 Clinical Practice Guidelines on the Management of Abdominal Aorto-Iliac Artery Aneurysms.

OBJECTIVE: The European Society for Vascular Surgery (ESVS) has developed clinical practice guidelines for the care of patients with aneurysms of the abdominal aorta and iliac arteries in succession to the 2011 and 2019 versions, with the aim of assisting physicians and patients in selecting the best management strategy. METHODS: The guideline is based on scientific evidence completed with expert opinion on the matter. By summarising and evaluating the best available evidence, recommendations for the evaluation and treatment of patients have been formulated. The recommendations are graded according to a modified European Society of Cardiology grading system, where the strength (class) of each recommendation is graded from I to III and the letters A to C mark the level of evidence. RESULTS: A total of 160 recommendations have been issued on the following topics: Service standards, including surgical volume and training; Epidemiology, diagnosis, and screening; Management of patients with small abdominal aortic aneurysm (AAA), including surveillance, cardiovascular risk reduction, and indication for repair; Elective AAA repair, including operative risk assessment, open and endovascular repair, and early complications; Ruptured and symptomatic AAA, including peri-operative management, such as permissive hypotension and use of aortic occlusion balloon, open and endovascular repair, and early complications, such as abdominal compartment syndrome and colonic ischaemia; Long term outcome and follow up after AAA repair, including graft infection, endoleaks and follow up routines; Management of complex AAA, including open and endovascular repair; Management of iliac artery aneurysm, including indication for repair and open and endovascular repair; and Miscellaneous aortic problems, including mycotic, inflammatory, and saccular aortic aneurysm. In addition, Shared decision making is being addressed, with supporting information for patients, and Unresolved issues are discussed. CONCLUSION: The ESVS Clinical Practice Guidelines provide the most comprehensive, up to date, and unbiased advice to clinicians and patients on the management of abdominal aorto-iliac artery aneurysms.

A Narrative Review of Experimental Assessment to Study Vascular Biomaterials Infections and Infectability.

Objective: Many experimental studies have been conducted to evaluate vascular and endovascular graft infections (VGEIs) and infectability in order to elaborate strategies to prevent or to treat their occurrence. A systematic literature search was conducted to collect and summarise key features of infection and infectability assessment techniques in VGEI experimental models. Methods: The literature search was conducted using the Medline and Cochrane databases, with no limit on the date of publication, until 10 August 2021. Ex vivo, in vitro, and in vivo animal studies on VGEIs, published in English or French, were selected. Cross references retrieved from selected articles on PubMed database were also included in the search. Data were collected on the techniques and the protocols performed for vascular graft infection and infectability assessment. Results: A total of 243 studies were included in the review: 55 in vitro studies, 169 animal studies, 17 combining the two models, and two ex vivo studies. Many experimental techniques were performed, with a lot of protocol discrepancies. The main experiments conducted were bacterial culture, with (n = 82 studies) or without sonication (n = 120), histopathology (n = 69), scanning electron microscopy (n = 36), and graft diffusion tests (n = 28). These techniques were used to answer different research questions corresponding to different graft infection steps, such as microbial adhesion and/or viability, biofilm biomass or organisation, human cell reaction, or antimicrobial activity. Conclusion: Many experimental tools are available to study VGEIs, but to improve their reproducibility and scientific reliability research protocols must be standardised and include sonication of grafts before microbiological culture. Moreover, the key role of the biofilm in VGEI physiopathology must be taken into account in future studies.

Staphylococcus aureus Adhesion and Biofilm Formation on Vascular Polyester Grafts are Inhibited In Vitro by Triclosan.

OBJECTIVE: This study evaluated Staphylococcus aureus adhesion and biofilm formation on vascular grafts, which has seldom been investigated. METHODS: Adhesion and biofilm formation capabilities of three methicillin susceptible S. aureus strains (one biofilm forming reference strain and two clinical isolates) on five different vascular biomaterials were evaluated in vitro, including polyester (P), P + gelatin (PG), P + collagen (PC), PC + silver (PCS), and PCS + triclosan (PCST). Staphylococcus aureus adhesion on grafts was evaluated after one hour of culture and biofilm formation after 24 hours of culture by four different methods: spectrophotometry after crystal violet staining; sonicate fluid culture; metabolic assay; and scanning electron microscopy (SEM). Optical density was compared using Mann-Whitney pairwise test, and bacterial counts using Wilcoxon pairwise test. RESULTS: PCST grafts were most efficient in preventing S. aureus adhesion and biofilm formation, regardless of the method used. Bacterial counts and metabolic activity were significantly lower on PCST grafts after 24 hours (5.65 vs. 9.24 [PCS], 8.99 [PC], 8.82 [PG], and 10.44 log10 CFU/mL [P]; p < .015), and only PCST grafts were bactericidal. Biofilm formation was significantly diminished on PCST grafts compared with all other grafts (p < .001). Bacterial viability and metabolic activity after 24 hours were more impaired on PG compared with PC graft, and were surprisingly higher on PCS compared with PC grafts. Biofilm biomass formed after exposure to P, PG, PC, and PCS grafts was also reduced after 24 hours of incubation with PCST grafts (p < .001). After 24 hours, few bacteria were visible by SEM on PCST grafts, whereas bacterial biofilm colonies were clearly identified on other graft surfaces. CONCLUSION: Triclosan impregnated PCST grafts appeared to interfere with S. aureus adhesion from early stages of biofilm formation in vitro. Silver impregnation was not efficient in preventing biofilm formation, and collagen coating promoted S. aureus biofilm formation more than gelatin coating.

BCG Aortitis, a Rare Complication of BCG Therapy.

Introduction: Intravesical Bacillus Calmette-Guerin (BCG) is an effective treatment for in situ bladder carcinomas; however, extravesical BCG infection may occur in remote organs in patients with underlying primary immunodeficiency and is a potentially serious complication in 3-5% of cases. It includes granulomatous pneumonia, hepatitis as well as specific dermatological, ophthalmic, and haematopoietic manifestations. Diagnosis is difficult and often based on high clinical suspicion as in many cases Mycobacterium bovis is not isolated. This report presents a rare case of BCGaortitis treated in a tertiary care centre. Report: A 74 year old man, with a history of bladder cancer treated with BCG therapy over a year ago, presented with malaise, abdominal pain, anorexia, and significant weight loss for several months associated with acute on chronic renal failure and a tender aneurysm. He was diagnosed with hepatic BCGitis and pararenal BCGaortitis. He was considered too high risk for open surgery after a multidisciplinary team meeting and was treated with a four vessel physician modified endograft (PMEG) and antituberculous therapy. At seven month follow up, he was clinically well and control computed tomography showed a patent endograft with complete exclusion of the aortic aneurysm. Discussion: Infectious BCG complications after intravesical BCG administration for in situ bladder carcinomas can lead to severe early and late complications. In the present case, the patient presented with both liver and aortic BCG infection. The lack of positive microbiological data should not discourage clinicians from considering BCG infection even if several months have passed since the last BCG instillation.

Multicenter Retrospective Study of Vascular Infections and Endocarditis Caused by Campylobacter spp., France.

The incidence of campylobacteriosis has substantially increased over the past decade, notably in France. Secondary localizations complicating invasive infections are poorly described. We aimed to describe vascular infection or endocarditis caused by Campylobacter spp. We included 57 patients from a nationwide 5-year retrospective study on Campylobacter spp. bacteremia conducted in France; 44 patients had vascular infections, 12 had endocarditis, and 1 had both conditions. Campylobacter fetus was the most frequently involved species (83%). Antibiotic treatment involved a ß-lactam monotherapy (54%) or was combined with a fluoroquinolone or an aminoglycoside (44%). The mortality rate was 25%. Relapse occurred in 8% of cases and was associated with delayed initiation of an efficient antimicrobial therapy after the first symptoms, diabetes, and coexistence of an osteoarticular location. Cardiovascular Campylobacter spp. infections are associated with a high mortality rate. Systematically searching for those localizations in cases of C. fetus bacteremia may be warranted.

Management of Inflammatory Aortic Aneurysms - A Scoping Review.

OBJECTIVE: Inflammatory abdominal aortic aneurysms (InflAAAs) account for 5 - 10% of aortic aneurysms and are characterised by retroperitoneal fibrosis. Diagnosis is often delayed, and doubts remain about the optimal management strategy. This scoping review describes the current state of knowledge on InflAAAs. METHODS: Medline, PubMed, EMBASE, and Scopus were searched for relevant studies that evaluated the diagnosis and treatment of InflAAAs. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol was followed. RESULTS: Fifty-seven papers were selected (low level of evidence), which included 1 554 patients, who were mostly male and heavy smokers. A triad of chronic abdominal or back pain, weight loss, and elevated inflammatory markers was highly suggestive of the diagnosis but rarely present, and fever was noted only randomly. A mantle sign was seen on computed tomography angiography (CTA) in 73 - 100% of patients. Open surgical repair (OSR) and endovascular aortic aneurysm repair (EVAR) was reported in 1 376 and 178 patients, respectively. OSR was associated with significant iatrogenic bowel (n = 22), urinary tract system (n = 7), venous (n = 30), pancreatic (n = 6), and splenic (n = 5) injuries, while EVAR was associated with lower 30 day mortality (0 - 5% vs. 0 - 32%). One and two year mortality rates were similar between the two treatment modalities (0 - 20% and 0 - 36%, respectively). EVAR was more often associated with post-operative progression of inflammation (17% vs. 0.4%), and a higher frequency of persistent hydronephrosis (> 50%) and limb occlusion (20%). Used in < 10% of patients, corticosteroids led to complete pain relief and a reduction in peri-aortic inflammation within 6 - 18 months. CONCLUSION: InflAAAs are characterised by non-specific symptoms, with the mantle sign on CTA being pathognomonic. Corticosteroids may be considered a basic treatment that all patients should receive initially. Low quality data indicate that EVAR (vs. OSR) is associated with fewer intra-operative complications and lower peri-operative mortality but more late fibrosis related adverse events. International multicentre registries are required to gather more insights into this challenging pathology.

Editor's Choice - Infective Native Aortic Aneurysms: A Delphi Consensus Document on Terminology, Definition, Classification, Diagnosis, and Reporting Standards.

OBJECTIVE: There is no consensus regarding the terminology, definition, classification, diagnostic criteria, and algorithm, or reporting standards for the disease of infective native aortic aneurysm (INAA), previously known as mycotic aneurysm. The aim of this study was to establish this by performing a consensus study. METHODS: The Delphi methodology was used. Thirty-seven international experts were invited via mail to participate. Four two week Delphi rounds were performed, using an online questionnaire, initially with 22 statements and nine reporting items. The panellists rated the statements on a five point Likert scale. Comments on statements were analysed, statements revised, and results presented in iterative rounds. Consensus was defined as ≥ 75% of the panel selecting "strongly agree" or "agree" on the Likert scale, and consensus on the final assessment was defined as Cronbach's alpha coefficient > .80. RESULTS: All 38 panellists completed all four rounds, resulting in 100% participation and agreement that this study was necessary, and the term INAA was agreed to be optimal. Three more statements were added based on the results and comments of the panel, resulting in a final 25 statements and nine reporting items. All 25 statements reached an agreement of ≥ 87%, and all nine reporting items reached an agreement of 100%. The Cronbach's alpha increased for each consecutive round (round 1 = .84, round 2 = .87, round 3 = .90, and round 4 = .92). Thus, consensus was reached for all statements and reporting items. CONCLUSION: This Delphi study established the first consensus document on INAA regarding terminology, definition, classification, diagnostic criteria, and algorithm, as well as reporting standards. The results of this study create essential conditions for scientific research on this disease. The presented consensus will need future amendments in accordance with newly acquired knowledge.

Retrospective Multicenter Study Comparing Infectious and Noninfectious Aortitis.

BACKGROUND: Determining the etiology of aortitis is often challenging, in particular to distinguish infectious aortitis (IA) and noninfectious aortitis (NIA). This study aims to describe and compare the clinical, biological, and radiological characteristics of IA and NIA and their outcomes. METHODS: A multicenter retrospective study was performed in 10 French centers, including patients with aortitis between 1 January 2014 and 31 December 2019. RESULTS: One hundred eighty-three patients were included. Of these, 66 had IA (36.1%); the causative organism was Enterobacterales and streptococci in 18.2% each, Staphylococcus aureus in 13.6%, and Coxiella burnetii in 10.6%. NIA was diagnosed in 117 patients (63.9%), mainly due to vasculitides (49.6%), followed by idiopathic aortitis (39.3%). IA was more frequently associated with aortic aneurysms compared with NIA (78.8% vs 17.6%, P < .001), especially located in the abdominal aorta (69.7% vs 23.1%, P < .001). Crude and adjusted survival were significantly lower in IA compared to NIA (P < .001 and P = .006, respectively). In the IA cohort, high American Society of Anesthesiologists score (hazard ratio [HR], 2.47 [95% confidence interval {CI}, 1.08-5.66]; P = .033) and free aneurysm rupture (HR, 9.54 [95% CI, 1.04-87.11]; P = .046) were significantly associated with mortality after adjusting for age, sex, and Charlson comorbidity score. Effective empiric antimicrobial therapy, initiated before any microbial documentation, was associated with a decreased mortality (HR, 0.23, 95% CI, .08-.71]; P = .01). CONCLUSIONS: IA was complicated by significantly higher mortality rates compared with NIA. An appropriate initial antibiotic therapy appeared as a protective factor in IA.

Reconstruction of primary and secondary aortic infections with an antimicrobial graft.

INTRODUCTION: In situ reconstruction (ISR) with autologous veins is the preferred method in infectious native aortic aneurysms (INAAs) or vascular (endo)graft infection (VGEI). However, access to biological substitutes can prove difficult and lacks versatility. This study evaluates survival and freedom from reinfection after ISR of INAA/VGEI using the antimicrobial Intergard Synergy graft combining silver and triclosan. METHODS: From February 2014 to April 2020, 86 antimicrobial grafts were implanted for aortic infection. The diagnosis of INAA/VGEI and reinfection was established based on the Management of Aortic Graft Infection Collaboration criteria. Survival was analyzed using the Kaplan-Meier method and log-rank P values. RESULTS: The antimicrobial graft was implanted in 32 cases of INAA, 28 of VGI, and 26 of VEI. The median age was 69.0 (interquartile range: 62.0; 74.0), with a history of coronary artery disease (n = 21; 24.4%), chronic kidney disease (n = 11; 12.8%), cancer (n = 21; 24.4%), and immunosuppression (n = 27; 31.4%). Imaging showed infiltration (n = 14; 16.3%), air (n = 10; 11.6%), and rupture (n = 16; 18.6% including 22 aortoenteric fistulae [AEnF]). Symptoms included fever (n = 37; 43.0%), shock (n = 11; 12.8%), and pain (n = 47; 54.7%). Repair was undertaken through a midline laparotomy in 75 cases (87.2%) and coeliac cross-clamping in 19 (22.1%), suprarenal in 26 (30.2%), plus celiac trunk (n = 3), mesenteric (n = 5), renal (n = 13), or hypogastric (n = 4) artery reconstruction, and omental flap coverage (n = 41; 48.8%). For AEnF, the gastrointestinal tract was repaired using direct suture (n = 14; 16.3%) or resection anastomosis (n = 8; 9.3%). Causative organisms were identified in 74 patients (86.0%), with polymicrobial infection in 32 (37.2%) and fungal coinfection in 7 (8.1%). Thirty-day and in-hospital mortality were 14.0% and 22.1% (n = 12 and 19, respectively, 3 INAA [9.4%], 7 VGI [25.0%], and 9 VEI [34.6%]). Seventy patients (81.4%) had a postoperative complication, 44 (51.2%) of whom returned to the operative room. The 1- and 2-year survival rates were 74.0% (95% confidence interval [CI]: 63.3-82.1) and 69.8% (95% CI: 58.5-78.5), respectively. Survival was significantly better for INAA vs VGEI (P = .01) and worse for AEnF (P = .001). Freedom from reinfection was 97.2% (95% CI: 89.2-99.3) and 95.0% (95% CI: 84.8-98.4) with six reinfections (7.0%) requiring two radiological/six surgical drainage and two graft removals. Primary patency was 88.0% (95% CI: 78.1-93.6) and 79.9% (95% CI: 67.3-88.1) with no significant difference between INAA and VGEI (P = .16). CONCLUSIONS: ISR of INAA or VGEI with the antimicrobial graft showed encouraging early mortality, comparable to the rates found in femoral vein (9%-16%) and arterial allograft (8%-28%) studies, as well as mid-term reinfection. The highest in-hospital mortality was noted for VEI including nearly 50% of AEnF.

Referral Centre Experience with Infected Abdominal Aortic Endograft Explantation.

OBJECTIVE: The increasing use of endovascular aneurysm repair (EVAR) appears to be associated with the burden of vascular endograft infections. Complete stent graft explantation is recommended but leads to significant mortality. This study aimed to assess the technical challenges, complications, and mortality rate following infected endograft explantation. METHODS: Patients who underwent abdominal aortic endograft explantation for infection at the Bordeaux University Hospital from July 2008 to December 2020 were included retrospectively in this single centre observational study. The diagnosis was established based on the MAGIC criteria. The primary endpoint was 30 day mortality. Secondary endpoints were 90 day and in hospital mortality, survival, and re-infection. RESULTS: Thirty-four patients were included, median age 69 years (interquartile range [IQR] 65, 76), with four (12%) treated as an emergency. The median time from EVAR to explantation was 17.5 months (4.5 - 36.3). In situ reconstruction was carried out with prosthetic grafts in 24 patients (71%, including 23 antimicrobial grafts combining silver and triclosan), and biological grafts in 10 (five femoral veins, four arterial allografts, three bovine patches, one biosynthetic graft). Seventeen aorto-enteric fistulae (AEnF) were addressed with direct repair of the intestinal tract (n = 10/17; 59%) or resection and anastomosis (n = 7/17; 41%). The culture was polymicrobial in 12 patients (35%) and remained sterile in four (12%). The 30 day and in hospital mortality rates were 21% (n = 7) and 27% (n = 9). Twenty-five patients (73%) presented with early post-operative complications, requiring 16 revision procedures (47%). Over a median follow up of 16.2 months (IQR 8.3, 33.6), the mortality rate was 35% (n = 12; 11 aortic related; 32%), with two re-infections (6%), both after biological reconstruction (one for an AEnF). CONCLUSION: Early morbidity and mortality remain high after complete infected endograft explantation, even in a high volume centre. Comparison with other treatment modalities in large multicentre cohorts might be of interest.

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.

Fully automatic volume segmentation using deep learning approaches to assess aneurysmal sac evolution after infrarenal endovascular aortic repair.

OBJECTIVE: Endovascular aortic repair (EVAR) surveillance relies on serial measurements of the maximal diameter despite significant inter- and intraobserver variability. Volumetric measurements are more sensitive; however, their general use has been hampered by the time required for their implementation. An innovative, fully automated software (PRAEVAorta; Nurea, Bordeaux, France), using artificial intelligence, had previously demonstrated fast and robust detection of the characteristics of infrarenal abdominal aortic aneurysms on preoperative imaging studies. In the present study, we assessed the robustness of these data on post-EVAR computed tomography (CT) scans. METHODS: We compared fully automatic and semiautomatic segmentation manually corrected by a senior surgeon (E.D.) using a dataset of 48 patients (48 early post-EVAR CT scans with 6466 slices and 101 follow-up CT scans with 13,708 slices). RESULTS: The analyses confirmed the excellent correlation of the post-EVAR volumes and surfaces and the proximal neck and maximum aneurysm diameters measured using the fully automatic and manually corrected segmentation methods (Pearson's coefficient correlation, >0.99; P < .0001). A comparison between the fully automatic and manually corrected segmentation methods revealed a mean Dice similarity coefficient of 0.950 ± 0.015, Jaccard index of 0.906 ± 0.028, sensitivity of 0.929 ± 0.028, specificity of 0.965 ± 0.016, volumetric similarity of 0.973 ± 0.018, and mean Hausdorff distance/slice of 8.7 ± 10.8 mm. The mean volumetric similarity reached 0.873 ± 0.100 for the lumen and 0.903 ± 0.091 for the thrombus. The segmentation time was nine times faster with the fully automatic method (2.5 minutes vs 22 minutes per patient with the manually corrected method; P < .0001). A preliminary analysis also demonstrated that a diameter increase of 2 mm can actually represent a >5% volume increase. CONCLUSIONS: PRAEVAorta enabled a fast, reproducible, and fully automated analysis of post-EVAR abdominal aortic aneurysm sac and neck characteristics, with a comparison between different time points. It could become a crucial adjunct for EVAR follow-up through the early detection of sac evolution, which might reduce the risk of secondary rupture.

A Narrative Review of Experimental Models to Study Vascular Grafts Infections.

Background: Many experimental models have been developed to decipher the mechanisms of vascular graft and endograft infections (VGEIs), and to elaborate strategies to prevent or treat their occurrence. A systematic literature research was conducted to identify the most accurate models for studying VGEIs, depending on the research question. Methods: A narrative literature search was conducted using the MEDLINE and Cochrane databases, with no set limit on the date of publication, up to 10 August 2021. Ex vivo, in vitro, and in vivo animal studies on VGEIs, published in English or French, were selected. Cross references retrieved from selected articles on PubMed database were also included. Data on microorganisms and grafts studied, details of experimental models, and of graft implantation and removal in animal studies were collected. Results: A total of 243 studies were included in the review after reading the full length articles: 55 in vitro studies, 169 animal studies, 17 studies which used both in vitro and animal models, and two ex vivo studies. Many differences in model characteristics were seen. The main in vitro model was the incubation of a graft sample in a bacterial solution, used to study the first steps of infection. In animals, vascular large animal models (dogs and pigs) were the most commonly described but supplanted over time by extravascular and particularly subcutaneous mouse and rat models, which have been reported increasingly over the last few years. In animal models, antibiotic prophylaxis and therapy were rarely administered (27.4% and 19.9%, respectively), and vascular reconstruction after VGEIs even less frequently (9.8%). Conclusion: Despite protocol discrepancies, it was possible to dinstinguish three main experimental models (i.e., in vitro and in vivo vascular models, and extravascular models), which all remain of interest to study specific phases of VGEIs.