OBJECTIVE:Treating abdominal aortic aneurysms with fenestrated or branched endovascular aneurysm repair in the presence of a median arcuate ligament (MAL) compression of the celiac trunk presents special challenges. This study aimed to investigate whether compressed celiac trunks can be safely stented or left unstented. It also aimed to assess the durability of bridging stent grafts (BSGs) of new generation in patients with compression of the celiac trunk. METHODS:A single-center retrospective analysis of 187 consecutive patients treated with fenestrated or branched endovascular aneurysm repair was performed. The study population was divided into three groups: patients whose MAL compression was stented with a BSG (MAL+ stented), patients whose MAL compression was not stented (MAL+ unstented), and patients without MAL compression (MAL-). Celiac trunk compression was evaluated in consecutive computed tomography angiography (CTA) scans. RESULTS:Of 187 patients, 76 patients (41%) had a MAL compression in the preoperative CTA scan. Of those, 46 patients (25%) were in the MAL+ stented group, and 30 patients (16%) were in the MAL+ unstented group. Six of 30 patients (20%) from the MAL+ unstented group developed mesenteric ischemia compared with zero of 46 patients (0%) from the MAL+ stented group (P ≤ .001). One of MAL+ stented patients (2%) developed target vessel instabilities, compared with one of MAL- patients (3%) and three of MAL- patients (3%) (P=.960). No BSG fracture was observed. CONCLUSIONS:BSGs of new generation are capable of withholding the pressure of MAL compression of the celiac trunk. Patients with unstented celiac trunk compression are significantly more likely to develop mesenteric ischemia. In accordance with present data, BSG deployment, including cases with high-grade stenosis, should be considered for maintenance of celiac blood flow.

OBJECTIVE:The European Society for Vascular Surgery (ESVS) has developed clinical practice guidelines for the care of patients with vascular graft or endograft infection (VGEI), in succession to the 2020 version, with the aim of assisting physicians and patients in selecting the best management strategy. METHODS:The guidelines are based on scientific evidence complemented with expert opinion. By summarising and evaluating the best available evidence, recommendations for the evaluation and management of patients with VGEI have been formulated. The recommendations are graded according to the ESVS grading system, where the strength (class) of each recommendation is graded from I to III, and the level of evidence from A to C. RESULTS:Eighty-one recommendations have been issued across the following main topics: definitions, diagnosis, multidisciplinary team management, antimicrobial therapy, management of intracavity or extracavity VGEI, and follow up. A chapter addresses the concept of shared decision making, with supporting information for patients. A final chapter addresses unresolved issues. CONCLUSION:These ESVS clinical practice guidelines provide comprehensive, up to date advice to clinicians and patients on the management of VGEI.

Objective To report the outcome of a wire-stabilized steerable sheath (SS group) approach for internal iliac artery (IIA) branch catheterization using contralateral transfemoral access and to compare its outcome to through-and-through wire technique (TnT group) for iliac branch device (IBD) procedures. Methods A retrospective analysis of 51 consecutive patients treated for aortoiliac or isolated IIA aneurysm from January 2020 to July 2023 was undertaken. Primary endpoints were radiation exposure, volume of contrast agent (CA), operation time and incidence of intraoperative target vessel (TV) complications. Type IB/C and IIIA/C endoleak, incomplete/complete thrombotic occlusion of TV, re-intervention rates at early (< 30 days after IBD), short (30 days - 6 months) and intermediate (> 6 months) follow-up were secondary endpoints. Results 12 patients in SS and 39 patients in TnT were identified. History of previous endovascular aneurysm repair (EVAR) was more prevalent in SS, p = 0.001. Non-significantly lower operation time (median, 204 vs. 262 min, p = 0.081) could be found in SS vs. TnT. Dose-area product (median, 301 vs. 361 Gy x cm(2)), CA (median, 148 vs. 190 mL) were non-significantly lower in SS vs. TnT. TV complications were observed in TnT only (7.7%). Incomplete/complete thrombotic occlusion of IIA branch was less frequently observed in SS vs. TnT at 3 follow-up phases (1 vs. 4 case, 1 vs. 5 case, respectively). Conclusions SS approach might be considered as a viable and technically safe option for patients with/without prior history of aortoiliac repair.

Cyclosporin A (CSA) is a potent immunosuppressive agent in pharmacologic studies. However, there is evidence for side effects, specifically regarding vascular dysfunction. Its mode of action inducing endothelial cell toxicity is partially unclear, and a connection with an adverse outcome pathway (AOP) is not established yet. Therefore, we designed this study to get deeper insights into the mechanistic toxicology of CSA on angiogenesis. Stem cells, especially induced pluripotent stem cells (iPSCs) with the ability of differentiation to all organs of the body, are considered a promising in vitro model to reduce animal experimentation. In this study, we differentiated iPSCs to endothelial cells (ECs) as one cell type that in other studies would allow to generate multi-cell type organoids from single donors. Flow cytometry and immunostaining confirmed our scalable differentiation protocol. Then dose and time course experiments assessing CSA cytotoxicity on iPS derived endothelial cells were performed. Transcriptomic data suggested CSA dependent induction of reactive oxygen species (ROS), mitochondrial dysfunction, and impaired angiogenesis via ROS induction which was confirmed by in vitro experiments. In order to put these data into a potential adverse outcome pathway (AOP) context, we performed a literature review for CSA-mediated endothelial cell toxicity and combined our experimental data with the publicly available knowledge. Such an AOP will help to design in vitro test batteries and to model events observed in human toxicity studies, as well in predictive toxicology.

AIMS:Abdominal aortic aneurysm (AAA) treatment is upon a diameter threshold. Attempts for medical growth abrogation have failed thus far. This study aims to elucidate the heterogeneity of AAA histomorphology in correlation with individual patient and aneurysm metrics. METHODS AND RESULTS:Samples from the left anterior aneurysm wall underwent histologic analysis including angiogenesis, calcification, fibrosis, type, and grade of inflammation in adventitia and media. Clinical information and state of aneurysm (intact, symptomatic, ruptured, and inflammatory) were retrieved. Semi-automated geometric analysis (Endosize©, Therenva, Rennes, France) and finite element methods (A4Clinics© Research Edition, Vascops GmbH, Graz, Austria) were included. A total of 364 patients' samples (85.4% male, median age 69 years) were scored for acute or chronic inflammation, both not associated with rupture (52×), symptomatic disease (37×), or diameter [57 (52-69) mm; P = 0.87]. The degree of fibrosis and the presence of angiogenesis were significantly higher (both P < 0.001) with increasing inflammation, which in turn significantly decreased with patient age (est = -0.015/year, P = 0.017). No significant differences were seen for acute (vs. elective), male (vs. female), or diabetic patients. Aneurysm geometry (n = 252) or annual growth rate (n = 142) were not associated with histologic characteristics. Yet, local luminal thrombus formation was significantly higher with increasing inflammation (P = 0.04). CONCLUSION:Type and degree of inflammation are the most distinguishable histologic characteristics in the AAA wall between individual patients, yet are not associated with diameter or rupture. Local luminal thrombus formation is associated with inflammatory features and suggests a vivid bio-physical compartment with intra-individual age-dependent differences.

OBJECTIVE:Preliminary observational studies have associated metformin prescription for diabetes treatment with reduced abdominal aortic aneurysm (AAA) growth progression. This proof of concept randomised controlled trial aimed to evaluate the efficacy of metformin intake on AAA growth progression in patients without diabetes. METHODS:This was a randomised, double blind, placebo controlled clinical trial of 2 g metformin vs. placebo in non-diabetic patients with AAA. Fifty eight patients with an infrarenal AAA with a maximum aortic diameter between 3.0 cm and 4.9 cm were included after a 14 day run in phase assessing drug tolerability. The recruitment target of 170 patients was not achieved due to the COVID-19 pandemic. The maximum aortic diameter and aneurysm volume were measured at baseline, after six and 12 months of treatment, and at 18 months follow up using computed tomography angiography. The pre-specified primary outcome was maximum aortic diameter change between baseline and 12 month visit. RESULTS:Differences in maximum aortic diameter from baseline to six, 12, and 18 months between the metformin and placebo groups were -0.10 mm (95% confidence interval [CI] -0.62 - 0.43 mm; p = .71), 0.16 mm (95% CI -0.70 - 1.02 mm; p = .72), and 0.31 mm (95% CI -0.86 - 1.48 mm; p = .59), respectively. The corresponding differences in aortic volume were -0.19 cm3 (95% CI -2.52 - 2.14 cm3; p = .87), 1.65 cm3 (95% CI -2.45 - 5.76 cm3; p = .42), and 2.10 cm3 (95% CI -3.45 - 7.65 cm3; p = .45). Amongst 58 randomised patients who completed the 12 month treatment phase, medication adherence was 94.9%. CONCLUSION:No difference in AAA growth between the metformin and placebo groups was observed. Patients had excellent adherence and tolerability to metformin therapy. Considering the lack of power of the study, larger randomised controlled trials with longer follow up are required to detect smaller treatment effects.

BACKGROUND:Biological graft options for vascular reconstruction following graft infection (VGI) of lower extremity remain scarce. Custom-made nature of previously reported bovine pericardial grafts (BPG) comes at an expense of serious material complications, including graft rupture and pseudoaneurysm. Lack of diagnostic modality defining VGI of lower limb entails inconsistency in VGI reporting rates. This study aimed to assess the outcome on prefabricated BPG for lower limb revascularization following VGI as classified using recently introduced MAGIC criteria. MATERIAL AND METHODS:A retrospective analysis of patients undergoing revascularization of lower extremity with pBPG between 2014 and 2022 was undertaken. Study population included two groups-cases with diagnosed VGI (VGI group), and cases with clinical suspicion for present/future graft infection in which pBPG were used prophylactically (PIV group). Limb salvage, 30-day mortality rates as well as primary, primary assisted and secondary patency rates comprised part of primary end points. Secondary endpoints included long-term mortality and the incidence of graft infection. RESULTS:A total of 50 patients underwent reconstruction with pBPG in a timespan of 8.5 years at a single institution. The underlying indication for surgery was lower extremity peripheral artery disease, 65.6% in VGI (n = 32) and 72.2% in PIV (n = 18) group. Two patients in VGI group (6.3%) died within 30-days postoperatively. Limb salvage could be achieved in 77.8% VGI and 81.3% in PIV group. Postoperative graft infection was observed more frequently in VGI (43.8%) vs. PIV (16.7%) groups. The microbial etiology of VGI, remained persistent (57.1%) and was diagnosed with an early onset (< 4 months postoperatively). CONCLUSION:The present study confirms the applicability of MAGIC criteria for peripheral VGI diagnosis and presents the largest case-series experience for the use of pBPG as a reliable biological substitute for revascularization procedures of lower extremity.

BACKGROUND:The infrarenal neck is a crucial anatomical segment for the repair of abdominal aortic aneurysm (AAA), requiring special attention when hostile neck features are present. The aim of the study was to perform a detailed morphological analysis of neck anatomy, hostility, progression and a prediction of neck length in the presence of AAA. METHODS:In total, 625 computed tomography angiographies (CTAs) of 114 patients, diagnosed with infrarenal AAA, were included. CTA-scanning was performed in 6-month intervals. Neck characteristics were assessed by determining length, diameter, angulation, shape, calcification and thrombus, and depending on these six parameters necks were classified in non-hostile, single-hostile, or multiple-hostile. Moreover, a prediction model for neck length decline was established. RESULTS:AAAs showed neck deterioration over time, with a 0.6 mm decrease in neck length for 1.0 mm increase in AAA diameter. Multiple-hostile neck characteristics were more common when the maximum AAA diameter exceeded 45 mm ( P = 0.003) or when the AAA volume increased to above 100 ml ( P = 0.029). At baseline, 39% of patients exhibited multiple-hostile neck anatomy compared to 52% at the last available measurement ( P ≤ 0.001), underlining the continuous progression of neck hostility. Single signs of hostile neck features in patients with AAAs <45 mm predicted for future neck hostility progression in one-third of patients. CONCLUSION:The neck deteriorates over time as AAA progresses in size, with development of neck hostility even before the maximum aortic diameter reaches the current threshold for repair of 50 mm/55 mm (women/men). The progressive nature of neck anatomy should be carefully considered when surveilling AAA patients and selecting them for future endovascular or open repair.

Abdominal aortic aneurysms (AAAs) are characterized by chronic inflammation, matrix degradation and smooth muscle cell (SMC) loss, leading to vessel dilation and rupture, with no current pharmaceutical management options. Since recent studies have highlighted the role of extracellular (ex) nucleic acids in promoting inflammation and tissue damage in cardiovascular conditions, we aimed to characterize the contribution of exDNA and exRNA to AAA pathogenesis and evaluate their potential as therapeutic targets in established disease. Circulating exDNA was elevated in patients and mouse models, while plasma levels of exRNA were not associated with AAA development. When RNase A or DNase I was administered to mice with established disease, the targeted degradation of exRNA, but not exDNA, significantly attenuated aneurysm growth. The RNase A treatment produced systemic anti-inflammatory effects (reduced monocyte/granulocyte count) and showed the potential to improve local vascular conditions by preserving SMC integrity, reducing macrophage infiltration and protease expression. These effects were not observed in DNase I-treated animals. In conclusion, while circulating exDNA showed AAA biomarker potential, targeting exRNA by systemic RNase A treatment effectively mitigated aneurysm progression in established disease through pleiotropic modulation of inflammation and tissue remodeling, presenting a novel and promising therapeutic strategy.

OBJECTIVE:To assess the spontaneous endoleak (EL) resolution rate and its associated factors in patients without aneurysm sac enlargement undergoing imaging surveillance with computed tomography angiography (CTA) following complex endovascular aneurysm repair procedures. METHODS:A retrospective analysis of 230 consecutive patients at a single institution was undertaken. In patients with type I/III/mixed EL at predischarge CTA without aneurysm sac enlargement, CTA surveillance was scheduled in 6 months after index procedure. Indication for secondary reintervention was given provided aneurysm sac enlargement of >5 mm in 6 months or >10 mm after 12 months. The primary end point was the EL resolution rate during follow-up. Secondary end points were patient-related, periprocedural, and morphological factors of spontaneous EL resolution over time. RESULTS:Predischarge CTAs have revealed ELs of any type in 75% of patients. Type I ELs did not resolve spontaneously over time. Type III ELs resolved spontaneously in 83% of cases at 24 months after the index procedure, with most resolution events being observed during the first 12 postinterventional months. Among mixed ELs, a combination of II/III ELs was found to resolve spontaneously over time (50% at 12 months). Spontaneous resolution between small (<9.37 mL) and large (>9.37 mL) volume ELs was compared, demonstrating at first no difference at 12 months and a tendency of faster EL resolution thereafter for small volume ELs. Maximum aortic diameter (P = .011), aneurysm sac shrinkage (P ≤ .001) and history of peripheral artery disease (P = .007) were found to be independent predictive factors of EL remission. No aneurysm sac rupture has been observed. CONCLUSIONS:Provided stable aneurysm sac dynamics, CTA surveillance might be considered for patients presenting type III EL or mixed type II/III EL at predischarge CTA scan.

Computational analysis of histopathological specimens holds promise in identifying biomarkers, elucidating disease mechanisms, and streamlining clinical diagnosis. However, the application of deep learning techniques in vascular pathology remains underexplored. Here, we present a comprehensive evaluation of deep learning-based approaches to analyze digital whole-slide images of abdominal aortic aneurysm samples from 369 patients from three European centers. Deep learning demonstrated robust performance in predicting inflammatory characteristics, particularly in the adventitia, as well as fibrosis grade and remaining elastic fibers in the tunica media from Hematoxylin and Eosin (HE)-stained slides (mean AUC > 0.70 in two external test cohorts). Models trained on Elastica van Gieson (EvG)-stained slides overall performed similar to models trained on HE-stained WSI for detection of calcification and fibrosis. For prediction of inflammatory parameters, HE-trained models performed considerably superior to EvG-trained models. Overall, this study represents the first comprehensive evaluation of computational pathology in vascular disease and has the potential to contribute to improved understanding of abdominal aortic aneurysm pathophysiology and personalization of treatment strategies, particularly when integrated with radiological phenotypes and clinical outcomes.

While the distinct roles of lymphocyte populations are well characterized in adaptive immunity, the phenotypic and functional diversity of innate immune cells is less explored. In recent years, subsets of monocytes have gained attention, as prominent shifts in population frequencies have been observed in disease states such as cancer. This narrative review summarizes current knowledge of the distribution and functional differences among the three major monocyte subsets (classical, intermediate, non-classical) in tumor settings. It includes rare populations, such as neutrophil-like, CD56+, and Tie2-expressing monocytes. Scientific evidence indicates that the phenotypical and functional heterogeneity of monocyte subsets determines their roles in either preventing cancer development or supporting the progression of disease through a remarkable diversity of mechanisms. Of note, alterations in the distribution of monocyte subsets and their functional reprogramming have been identified as drivers of cancer progression. While changes in monocyte frequencies have limited diagnostic biomarker potential for cancer detection, they may reflect the progression of disease and response to therapy. Based on subset-specific properties, distinct monocyte populations are increasingly recognized as promising targets of cancer immunotherapy. Yet novel strategies targeting monocyte populations must consider the risk of treatment reversal given the high plasticity of these cells.

OBJECTIVES:Our study aims at characterizing the intraspinal vascular perfusion territories (angiosomes) of the descending thoracic aorta in a cadaver stetting to understand the principles of blood supply to the spinal cord and to provide the anatomic basis for strategies to avoid spinal ischaemia during aorta surgery. METHODS:Simulating blood flow in the descending thoracic aorta and thoracic aortic segmental arteries T3-T11 of 8 body donors were perfused with dyed liquids to label the epidural and spinal cord angiosomes. RESULTS:The cranial and caudal borders of the spinal cord angiosome varied substantially with a maximum extension from segment C7 to the conus medullaris. In 5 specimens, the anterior and posterior aspects differed for 1-2 segments. In 75%, the anterior spinal artery appeared to be stained along the entire spinal cord, and in 4 specimens, a voluminous Adamkiewicz artery joined its lower thoracic segments. In 3 of those specimens, this caused the spinal cord angiosome to be stained caudally towards the conus medullaris. In addition to details on the spinal cord angiosome, details on the epidural angiosome and the antero- and retrograde perfusion of the spinal nerve roots and the influence of thoracic aortic segmental artery variations are provided. CONCLUSIONS:Our study characterizes both intraspinal descending thoracic aorta angiosomes. It demonstrates the importance of the Adamkiewicz and the anterior spinal arteries for blood supply to the spinal cord and the nerve root fibers.

Background: Abdominal aortic aneurysm (AAA) is a multifactorial vascular disease with limited therapeutic options, as no pharmacological treatments currently exist to mitigate the progression of small AAAs. Quality of life (QoL) has emerged as a valuable supplementary metric for assessing the efficacy of pharmacological interventions. This study evaluated QoL scores of MetAAA trial patients on metformin therapy compared to those with placebo intake. Methods: Overall, 54 patients with AAA were included in the MetAAA trial (ClinicalTrials.gov-Identifier:NCT03507413) and randomized to either metformin or placebo treatment. All participants were asked to complete three established and validated (in total 659 longitudinally collected) QoL questionnaires: (1) the 36-Item Short Form Health Survey (SF-36), (2) the Aneurysm Symptom Rating Questionnaire (ASRQ), and (3) the Aneurysm-Dependent Quality of Life questionnaire (ADQoL). Results: A superior health-related QoL was found in metformin-treated AAA patients compared to enrolled AAA patients receiving a placebo. In detail, AAA patients undergoing metformin treatment showed a superior overall current QoL score (p = 0.038), general health perception (p = 0.013), improved physical functioning (p = 0.004), and increased energy/lower fatigue scores (p = 0.008). Furthermore, fewer limitations due to cognitive distress (p = 0.001) and lower limb function (p = 0.021) were detected. Other QoL subscales did not show statistical significance. Inflammatory blood parameters suggest that while systemic inflammation may have some impact on perceived QoL, the relationship is largely limited. Conclusions: In patients with small AAA, metformin led to a limited improvement in health-related QoL compared to a placebo.

Objectives: The mechanisms linking vitamin D deficiency to carotid artery stenosis (CAS) remain unclear. Data on cardiovascular outcomes in CAS patients with vitamin D deficiency are limited. We investigated the association of vitamin D deficiency with carotid plaque morphology and patient outcomes in high-grade CAS. Methods: A total of 332 patients undergoing carotid endarterectomy for symptomatic (n = 113, 34%) or asymptomatic (n = 219, 66%) CAS were included. Preoperative vitamin D levels were measured, and duplex sonography was used to assess luminal narrowing. Associations of vitamin D with clinical presentation were analyzed using univariate and multivariate linear regression. For vitamin D deficiency and the prediction of major adverse cardiovascular events (MACE) and all-cause mortality, the Cox proportional hazard regression model was used. Results: The median age was 69 years (interquartile range (IQR) 64-74), and 94 (29.3%) patients were female. Vitamin D deficiency was present in 84 (25%) patients. Symptomatic patients had significantly lower vitamin D levels (41.2 nmol/L, IQR 25.1-63.5) than asymptomatic patients (51.6 nmol/L, IQR 30.5-74.3, p = 0.011). Patients with echolucent (44.9 nmol/L, IQR 27.4-73.7) or mixed plaques (39.2 nmol/L, IQR 22.9-63.5) had lower vitamin D levels than those with echogenic plaques (52.3 nmol/L, IQR 34.1-75.7). Vitamin D deficiency predicted MACE and all-cause mortality with an adjusted HR of 1.6, 95% CI of 1.1-2.6, and p = 0.030 and an HR of 2.2, 95% CI of 1.3-3.6, and p = 0.002, respectively, in a multivariable Cox proportional hazard regression model. Conclusions: A deficiency in vitamin D was correlated with unstable plaque characteristics and symptomatic CAS. Furthermore, vitamin D deficiency was associated with long-term adverse cardiovascular outcomes and mortality, suggesting its potential as a modifiable risk factor for improved risk stratification in patients undergoing carotid endarterectomy.

Objective:Spinal cord ischemia due to damage or occlusion of the orifices of aortic segmental arteries (ASA) is a serious complication of open and endovascular aortic repair. Our study aims to provide detailed descriptions of the proximal course of the ASAs and metric information on their origins. Materials and methods:Initially, 200 randomly selected, embalmed cadavers of human body donors were anatomically dissected and systematically examined. On macroscopic inspection, 47 showed severe pathologies and were excluded. Of the remaining 153, 73 were males and 80 females. Results:In total, 69.9% of the aortae showed 26-28 ASA orifices. In 59.5% the most proximal ASA, at least unilaterally, was the third posterior intercostal artery, which originated from the descending aorta at approximately 10% of its length. In 56.2%, the left and right ASAs had a common origin in at least one body segment. This mainly affected the abdominal aorta and L4 in particular (54.2%). The ASAs of lumber segments 1-3 originated strictly segmentally. In contrast, in 80.4%, at least one posterior intercostal artery originated from a cranially or caudally located ipsilateral ASA. Such an arrangement was seen along the entire thoracic aorta. Further descriptions of variants and metric data on ASA orifices are presented. Conclusion:Our large-scale study presents a detailed topographic map of ASAs. It underscores the value of preoperative CT councils and provides crucial information for interpreting the results. Furthermore, it aids in planning and conducting safe aortic intervention and assists in deciding on single- or two-staged stent graft procedures.

Neutrophil extracellular traps (NETs), composed of DNA, histones, and antimicrobial proteins, are released by neutrophils in response to pathogens but are also recognized for their involvement in a range of pathological processes, including autoimmune diseases, cancer, and cardiovascular diseases. This review explores the intricate roles of NETs in different cardiovascular conditions such as thrombosis, atherosclerosis, myocardial infarction, COVID-19, and particularly in the pathogenesis of abdominal aortic aneurysms. We elucidate the mechanisms underlying NET formation and function, provide a foundational understanding of their biological significance, and highlight the contribution of NETs to inflammation, thrombosis, and tissue remodeling in vascular disease. Therapeutic strategies for preventing NET release are compared with approaches targeting components of formed NETs in cardiovascular disease. Current limitations and potential avenues for clinical translation of anti-NET treatments are discussed.

Objective Abdominal aortic aneurysm (AAA) treatment is upon a diameter threshold by open (OAR) or endovascular aortic repair. So far, attempts for medical growth abrogation have failed. This study aims to elucidate the heterogeneity of AAA based on histomorphology in correlation to individual patient data and aneurysm metrics.Patients and Methods Aneurysm samples from the left anterior wall from four university center biobanks underwent histologic analysis including angiogenesis, calcification, fibrosis, type and grade of inflammation in adventitia and media. Clinical information included age, comorbidities, etc., type of aneurysm (intact, symptomatic, ruptured, inflammatory) and growth. Aneurysm morphology included diameter and semi-automated geometric analysis using Endosize© (Therenva) and finite element methods (A4Clinics© Research Edition, Vacops GmbH).Results 364 patients’ samples (85.4% male, median age 69 years) were evaluated and scored for acute (mixed/granulocytes) or chronic (mononuclear/plasma cells) inflammation, which was not associated with rupture (52x), symptomatic (37x; p = 0.51) or diameter (57 [52–69] mm; p = 0.87). The degree of fibrosis and the presence of angiogenesis were significantly higher (both p < 0.001) with increasing inflammation, which in turn significantly decreased with patient age (est = −0.015/year, p = 0.017). No significant differences in were seen for ruptured (vs. intact), acute (vs. elective), male (vs. female) or diabetic patients. Current smoking was associated with chronic inflammation (p = 0.007) and a higher degree of fibrosis (p = 0.03). Aneurysm geometric morphology (n=252) or annual growth rate (n=142) were not associated with histologic characteristics. Yet, local luminal thrombus formation was significantly higher with increasing inflammation (p = 0.04).Conclusion Type and degree of inflammation are the most distinguishable histologic characteristics in the AAA wall between individual patients, yet not associated with diameter or rupture. Local luminal thrombus formation is associated with inflammatory features and suggests a vivid bio-physical compartment with intra-individual differences.### Competing Interest StatementThe authors have declared no competing interest.### Funding StatementA one-year license of EndoSize (Therenva) and A4clinics Research Edition (Vascops) was funded by the German Heart Foundation (Deutsche Herzstiftung) with a grant given to A Busch (F/46/18).### Author DeclarationsI confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.YesThe details of the IRB/oversight body that provided approval or exemption for the research described are given below:The study was performed in accordance with the declaration of Helsinki and tissue sampling was approved by the local ethics committees of the individual centers (Ethikkommission Klinikum rechts der Isar: 2799/10; Ethikkommission Duesseldorf: 2019-578; Ethikkommission Wuerzburg: 188/11; Ethikkommission Wien: Ref 1729/2014). The HistAAA study was specifically approved for the leading center (Ethikkommission Klinikum rechts der Isar: 576/18S).I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.YesI understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).YesI have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable.YesAll data produced in the present work are contained in the manuscript