Abdominal aortic aneurysms

A computed tomography angiography-based radiomics model for prognostic prediction of endovascular abdominal aortic repair

OBJECTIVE

This study aims to develop a radiomics machine learning (ML) model that uses preoperative computed tomography angiography (CTA) data to predict the prognosis of endovascular aneurysm repair (EVAR) for abdominal aortic aneurysm (AAA) patients.

METHODS

In this retrospective study, 164 AAA patients underwent EVAR and were categorized into shrinkage (good prognosis) or stable (poor prognosis) groups based on post-EVAR sac regression. From preoperative AAA and perivascular adipose tissue (PVAT) image, radiomics features (RFs) were extracted for model creation. Patients were split into 80 % training and 20 % test sets. A support vector machine model was constructed for prediction. Accuracy is evaluated via the area under the receiver operating characteristic curve (AUC).

RESULTS

Demographics and comorbidities showed no significant differences between shrinkage and stable groups. The model containing 5 AAA RFs (which are original_firstorder_InterquartileRange, log-sigma-3-0-mm-3D_glrlm_GrayLevelNonUniformityNormalized, log-sigma-3-0-mm-3D_glrlm_RunPercentage, log-sigma-4-0-mm-3D_glrlm_ShortRunLowGrayLevelEmphasis, wavelet-LLH_glcm_SumEntropy) had AUCs of 0.86 (training) and 0.77 (test). The model containing 7 PVAT RFs (which are log-sigma-3-0-mm-3D_firstorder_InterquartileRange, log-sigma-3-0-mm-3D_glcm_Correlation, wavelet-LHL_firstorder_Energy, wavelet-LHL_firstorder_TotalEnergy, wavelet-LHH_firstorder_Mean, wavelet-LHH_glcm_Idmn, wavelet-LHH_glszm_GrayLevelNonUniformityNormalized) had AUCs of 0.76 (training) and 0.78 (test). Combining AAA and PVAT RFs yielded the highest accuracy: AUCs of 0.93 (training) and 0.87 (test).

CONCLUSIONS

Radiomics-based CTA model predicts aneurysm sac regression post-EVAR in AAA patients. PVAT RFs from preoperative CTA images were closely related to AAA prognosis after EVAR, enhancing accuracy when combined with AAA RFs. This preliminary study explores a predictive model designed to assist clinicians in optimizing therapeutic strategies during clinical decision-making processes.

Volumetric Abdominal Aortic Aneurysm Analysis in Post EVAR Surveillance Settings

BACKGROUND

Early detection of abdominal aortic aneurysms (AAA) is a mainstay of diagnosis, with endovascular aneurysm repair (EVAR) emerging as the primary mode of repair. Maximum diameter measurement remains central to risk assessment; however, recent studies suggest AAA volumetric analysis may be more sensitive to true size changes. We compare the utility of volume and diameter in AAA size assessment and further investigate related clinical factors.

METHODS

We retrospectively reviewed all patients who underwent EVAR at our institution between August 2017 and March 2023 with available pre and postoperative computed tomography (CT) angiograms. AAA total aneurysm and lumen volume were measured using semiautomatic segmentations. The maximum diameter and clinical variables were extracted from the medical record. The direct comparison of volume to diameter was completed using percent change from baseline. A subgroup of patients with long-term follow-up (LTFU) data (>231 days between scans) were used for additional analyses.

RESULTS

Of 116 patients, 69 (59.5%) were included in the long-term patient cohort. Postintervention, percent change volume and percent change diameter had a moderate positive correlation (rs = 0.6662), and average AAA percent change did not differ between volume and diameter (1.5% vs. -1.8%, respectively; P = 0.1654). Volumetric analysis was more likely to detect aneurysm sac enlargement (P = 0.0315). On univariable analysis, increase in volume and diameter was associated with older age and endoleak. A diameter decrease was associated with metformin therapy.

CONCLUSION

Aneurysm volume is more likely to detect AAA enlargement than diameter. The benefit of early detection of high-risk aneurysms may translate to changes in surveillance and ultimately decrease aneurysm-related mortality.

Inhibition of VSMC Ferroptosis Mitigates Pathological Vascular Remodeling: A Novel Therapeutic Strategy for Abdominal Aortic Aneurysm

Ferroptosis plays a key role in abdominal aortic aneurysm (AAA) development. This study explores whether and how ferroptosis regulates AAA progression. Ferroptosis was confirmed in human AAA tissue. In vitro experiments with primary mouse vascular smooth muscle cells (VSMCs) and abdominal aortic rings revealed that angiotensin II (Ang II) triggered ferroptosis in VSMCs. Ferrostatin-1 (Fer-1), a potent ferroptosis inhibitor, effectively suppressed this effect. Additionally, the ferroptosis inducer erastin and Ang II can both promoted pathological remodeling of abdominal aortic rings, but Fer-1 significantly suppressed these effects. In AAA mouse model, Fer-1 treatment reduced AAA formation. Mechanistically, RNA-sequencing analysis revealed that Fer-1 regulates VSMC contractile function, suppresses inflammation, and mitigates extracellular matrix remodeling. These findings highlight the critical role of VSMC ferroptosis in AAA pathogenesis and demonstrate that ferroptosis inhibition effectively reduces pathological vascular remodeling, making it a promising therapeutic strategy for preventing AAA.

RAGE deficiency ameliorates abdominal aortic aneurysm progression

BACKGROUND

Abdominal aortic aneurysm (AAA) is a vascular disease characterized by inflammation and arterial wall degradation. The receptor for advanced glycation end products (RAGE) plays a pivotal role in regulating inflammatory pathways, but its specific contribution to AAA pathogenesis remains unclear.

PURPOSE

This study aimed to investigate the role of RAGE in AAA development by examining its expression in human and mice AAA tissues and exploring the effects of RAGE deficiency on aneurysm progression, macrophage polarization, and inflammatory responses.

METHODS

RAGE expression was analyzed in human AAA samples and porcine pancreatic elastase (PPE) induced AAA mouse models using Western blotting, immunohistochemistry, and immunofluorescence. In vivo RAGE-deficient (RAGE-/-) mice were generated to assess the impact of RAGE knockout on AAA progression. In vitro experiments utilized RAW264.7 transfected with RAGE-targeting siRNA to study macrophage polarization and NF-κB signaling.

RESULTS

RAGE expression was elevated in AAA tissues, particularly in macrophages. RAGE-/- mice exhibited reduced AAA incidence, mortality, and aortic dilation compared to wild-type mice. Histological analysis showed preserved elastic fibers and smooth muscle layers, along with decreased inflammatory cell infiltration and MMP2/MMP9 expression. RAGE deficiency inhibited M1-like macrophage polarization and pro-inflammatory cytokine secretion, mediated through suppression of the NF-κB pathway.

CONCLUSIONS

RAGE deficiency mitigates AAA progression by modulating macrophage polarization and reducing inflammation via the NF-κB pathway. These findings highlight RAGE as a potential therapeutic target for AAA treatment.

Emergency Ultrasound in the Context of Cardiac Arrest and Circulatory Shock: "How to Avoid Cardiac Arrest"

In the recently published 2021 European Resuscitation Council Guidelines on Adult Advanced Life Support, focused echocardiography was upgraded to a target recommendation. Several key recommendations were made, including that point-of-care ultrasound (POCUS) should only be used during CPR performed by experienced users and prolonged interruptions longer than 10 s (as accepted for pulse checking) during chest compressions should be avoided. Ultrasound does not replace clinical evaluation nor awareness of the clinical scenario. However, in addition to other assessments such as laboratory analyses, ultrasound can help to directly identify a cause for the peri-arrest state. The advantage of ultrasound is that examinations can be performed at the bedside while other tests are being carried out and repeated as frequently as required. This article focusses on how to use ultrasound during peri-arrest situations, requirements for ultrasound equipment, reversible causes of cardiac arrest, and the use of the RUSH protocol, focused echocardiography, and "deresuscitation" (post resuscitation/return of spontaneous circulation).

Chronic Kidney Disease is a Stronger Predictor for Mortality than Charlson Comorbidity Index After Abdominal Aortic Aneurysm Repair

INTRODUCTION

Patients undergoing abdominal aortic aneurysm (AAA) repair face elevated mortality risk associated with advanced age and comorbidities including chronic kidney disease (CKD). CKD alone demonstrates an increased risk for mortality in patients. Our cohort study aimed to identify whether CKD and/or comorbid burden using the Charlson Comorbidity Index (CCI) are potential contributors towards negative outcomes in patients who underwent AAA repair.

METHODS

We conducted a single-center retrospective cohort study on patients undergoing AAA repair between 2014-2024. The primary outcome is comorbidity burden (measured with CCI), and disease-specific burden (CKD measured by glomerular filtration rate (GFR)), as contributors to increased risk for mortality. Secondary outcomes included 30-day and mid-term complications and reinterventions after AAA repair. Propensity score matching was also conducted based on age, sex, hypertension, diabetes, smoking status, and coronary artery disease to assess for CKD and CCI burden.

RESULTS

A total of 212 matched patients underwent AAA repair, with 106 patients in the No-CKD (GFR ≥ 60 mL/min) group and 106 in the CKD (GFR < 60 mL/min) group. Sociodemographic variables, including age (No-CKD: 75.29 ± 8.17 vs. CKD: 75.94 ± 8.80; p=0.576), sex proportions (p=0.846), and mean household income (No-CKD: $99,199.08 ± 37,846.82 vs. CKD: $91,333.38 ± 32,128; p=0.091), were similar between groups. Patients with CKD had significantly higher CCI scores (No-CKD: 4.99 ± 1.96 vs. CKD: 6.11 ± 2.26; p<0.001). Thirty-day complications (No-CKD: 5.7% vs. CKD: 7.5%; p=0.580) and aortic-related reintervention rates (No-CKD: 13.2% vs. CKD: 12.3%; p=0.837) were comparable between groups. Mortality was significantly higher in the CKD group (No-CKD: 17.9% vs. CKD: 32.1%; p=0.017). Logistic regression analysis demonstrated that stage 5 CKD (OR: 9.33, 95% CI: 1.26-97.09; p=0.04), CKD (OR: 2.16 95% CI: 1.15-4.17; p=0.018), and CCI score (OR: 1.42, 95% CI: 1.26-1.67; p < 0.001) are significantly associated with mortality.

CONCLUSION

Higher CCI and CKD stage are risk factors for a higher mortality rate in patients who underwent AAA repair. Subgroup analysis between CKD stages demonstrated that stage 5 has a stronger association with mortality than CCI. Strategies to decrease mid-term mortality rates might include enhanced preoperative optimization, and individualized approach to care.

Inulin Diet Alleviates Abdominal Aortic Aneurysm by Increasing Akkermansia and Improving Intestinal Barrier

Background/Objectives: Previous studies have shown varying efficacy of high-fiber diets containing different ingredients in abdominal aortic aneurysms (AAAs). This study aimed to identify which high-fiber diet protects against AAA in mice and elucidate the underlying mechanisms. Methods: This study compared inulin, cellulose, and chow diets in terms of their impact on aneurysm enlargement, elastin degradation, matrix metalloproteinase 2 and 9 expressions, CD3+ T cell and CD68+ macrophage infiltration, and macrophage differentiation. It also examined gut microbiota composition, focusing on Akkermansia, and evaluated intestinal barrier function and systemic inflammatory response. Results: The inulin diet, but not the cellulose diet, compared with the chow diet, reduced aneurysm enlargement, elastin degradation, matrix metalloproteinase 2 and 9 expressions, CD3+ T cell and CD68+ macrophage infiltration, and skewed macrophage towards M2 differentiation. The inulin diet enriched Akkermansia in both the small and large intestine. The inulin diet also enhanced the intestinal barrier by augmenting goblet cells, upregulating the gene related to the epithelial barrier and antibacterial peptides in the small intestine, and reducing circulating lipopolysaccharide and interleukin-1β levels. The inulin diet lowered the proportion of Ly6Chi monocytes and C-C chemokine receptor 2 expression on these cells in the bone marrow, reducing aneurysm infiltration. Administering Akkermansia to AAA mice decreased intestinal permeability and mitigated AAA. Conclusions: A diet rich in fermentable fiber inulin, as opposed to cellulose, alleviates AAA in mice. This beneficial effect is attributed to the enhanced presence of Akkermansia bacteria and improvement of the intestinal barrier.

Modulation of arterial wall remodeling by mechanical stress: Focus on abdominal aortic aneurysm

The rupture of an abdominal aortic aneurysm (AAA) poses a significant threat, with a high mortality rate, and the mechanical stability of the arterial wall determines both its growth and potential for rupture. Owing to extracellular matrix (ECM) degradation, wall-resident cells are subjected to an aberrant mechanical stress environment. In response to stress, the cellular mechanical signaling pathway is activated, initiating the remodeling of the arterial wall to restore stability. A decline in mechanical signal responsiveness, coupled with inadequate remodeling, significantly contributes to the AAA's progressive expansion and eventual rupture. In this review, we summarize the main stresses experienced by the arterial wall, emphasizing the critical role of the ECM in withstanding stress and the importance of stress-exposed cells in maintaining mechanical stability. Furthermore, we will discuss the application of biomechanical analyses as a predictive tool for assessing AAA stability.

Echocardiographic analysis of abdominal aorta dimensions and their associations with demographic characteristics in a healthy population

INTRODUCTION

Determining the normal diameter of the abdominal aorta in different populations and its relationship with other demographic factors is crucial for diagnosing and managing abdominal aortic diseases. This study aimed to assess the size of the abdominal aorta in a healthy Iranian population.

METHODS

This cross-sectional study included healthy individuals. Various variables including age, sex, height, and weight were measured as part of this study. We performed an echocardiographic evaluation to assess the aortic sections.

RESULTS

The study encompassed 167 participants, predominantly women (67.7%). Notable differences in sizes of the ascending aorta, aortic arch, sinus of Valsalva, and abdominal aorta were observed across the four age groups. Men exhibited greater sizes in multiple aortic sections within the 45-64 age group. Correlation and regression analyses demonstrated significant positive relationships between abdominal aorta size and various aortic dimensions, with a one-millimeter increase in ascending or descending aorta diameter corresponding to a 0.23 and 0.35 mm increase, respectively, in abdominal aorta diameter. The relationship between abdominal aorta size and demographic factors such as gender, age, weight, BSA, and SBP was explored, revealing age as a significant predictor.

CONCLUSIONS

We observed significant differences in the sizes of distinct aortic sections across different age groups, underscoring the importance of considering age-related changes when evaluating aortic characteristics. These findings contribute to our understanding of the structural changes that occur in the aorta over time. Echocardiographic screening of the abdominal aorta would enable echocardiologists to diagnose the aneurysmal aorta.

Functional anti-inflammatory mesoporous silica nanoplatform for Synergistic and Targeted abdominal aortic aneurysm treatment

Abdominal aortic aneurysm (AAA) is a chronic inflammation-driven disease characterized by aortic wall destruction and expansion, leading to high morbidity and mortality. However, previous drug treatments for its common risk factors have not achieved favorable results, and the early prevention and treatment is still the main clinical dilemma. Anti-inflammation therapy is a promising therapeutical method targeting its pathogenesis mechanism, but it has not been explored in depth. Herein, interleukin-1 receptor antagonist-loaded manganese-doped mesoporous silica nanoparticles (IL-1Ra@MMSN) were designed and synthesized to target macrophage-mediated chronic aortic inflammation for AAA treatment. IL-1Ra@MMSN showed high IL-1Ra-loading efficiency, great stability and pH-responsive drug-releasing property. IL-1Ra@MMSN specially phagocytosed by macrophages can protect against oxidative stress injury and promoted the M2 polarization via transforming growth factor-β (TGF-β) signaling in vitro. Furthermore, IL-1Ra@MMSN exhibited good lesion targeting ability, hemocompatibility and biocompatibility in angiotensin II-induced murine AAA model. In vivo experiments also confirmed the excellent treatment efficacy in reducing AAA formation and progression via protecting aortic wall integrity and promoting anti-inflammatory microenvironment. Taken together, the current study demonstrated that IL-1Ra@MMSN is a promising nanoplatform for early intervention of AAA, which provides a novel treatment strategy based on anti-inflammatory immune regulation.

Identifying nexilin as a central gene in neutrophil-driven abdominal aortic aneurysm pathogenesis

OBJECTIVES

Abdominal aortic aneurysm (AAA) is an inflammation-driven disease in which neutrophil infiltration is critical to its progression. This study aims to explore the molecular mechanisms behind neutrophil infiltration in AAA and identify key regulatory genes.

METHODS

We utilized weighted gene co-expression network analysis (WGCNA) and differential gene expression analysis to compare AAA and healthy abdominal aortic tissues. Functional enrichment analysis and a protein-protein interaction (PPI) network were constructed to understand gene functions. Machine learning algorithms were applied to identify key hub genes, followed by in vivo validation using an ApoE-/- mouse model.

RESULTS

Neutrophils, NK cells, and pDCs were significantly increased in AAA tissues. WGCNA identified 234 genes associated with neutrophil infiltration, of which 39 were significantly differentially expressed. Functional enrichment analysis highlighted roles in actin-related processes and pathways. Nexilin (NEXN) was consistently identified as a key hub gene negatively correlated with immune cell infiltration. In vivo validation confirmed that NEXN inhibits AAA progression in ApoE-/- mice by regulating immune cell infiltration.

CONCLUSION

NEXN plays a crucial role in modulating neutrophil infiltration in AAA. These findings provide new molecular insights into AAA pathogenesis and suggest NEXN as a potential target for AAA therapy.

Aged Garlic Extract Attenuates CaCl2-Induced Abdominal Aortic Aneurysm Formation by Inhibiting Matrix Metalloproteinase 9 Expression in Macrophages

Abdominal aortic aneurysm (AAA) is a local enlargement of the abdominal aorta with the risk of its fatal rupture. With lack of established medical treatments reducing the AAA growth, the development of treatment strategies for AAA is warranted. In this study, we examined whether aged garlic extract (AGE), which reportedly has vasoprotective effects, attenuates AAA formation in an animal model. AAAs were induced via CaCl2 application to the abdominal aortas of C57BL/6J mice. The intake of an AGE-containing diet attenuated the aortic dilatation after AAA induction. Histological analysis showed that the degradation of elastic fibers in AAAs was mild in mice fed AGE compared to that in control mice. In addition, the expression of matrix metalloproteinase 9 (MMP9), a proteolytic enzyme degrading aortic tissue, was decreased in AAAs from mice fed with AGE. In cultured macrophages, AGE significantly inhibited tumor necrosis factor (TNF)-α-induced Mmp9 mRNA expression. Furthermore, AGE attenuated TNF-α-induced extracellular signal-regulated kinase (ERK) phosphorylation and c-fos mRNA expression, suggesting the suppressive effect of AGE on ERK-c-Fos-MMP9 axis induced by TNF-α. The present findings indicate that AGE diminishes AAA formation by mitigating tissue destruction, highlighting the potential cardiovascular benefits of AGE intake.

The Justification of Open Surgical Repair for an Abdominal Aortic Aneurysm: A Retrospective Comparison of Outcomes of Endovascular Aneurysm Repair and a Brief Review of the Literature

Background: Abdominal aortic aneurysms (AAAs) are life-threatening conditions that require timely intervention to prevent rupture. Endovascular aneurysm repair (EVAR) is preferred due to faster recovery and lower perioperative risk; however, intraoperative failure and long-term complications highlight the continued significance of open surgical repair (OSR) and the need for improved risk assessment. Methods: This retrospective study analyzed data from 210 patients who underwent EVAR (n = 163) or OSR (n = 47) at a single center. Clinical characteristics, complications, reintervention rates, and 30-day mortality were recorded. EVAR-to-OSR conversion and mortality predictors in AAA treatments were identified. Results: The overall mortality rate was 9.5% (20/210 patients), with 12 patients (7.3%) in the EVAR group and 8 patients (17%) in the OSR group (p = 0.085). Five patients required early and six required late conversion to open surgery. In follow-ups beyond 30 days, the reintervention rate for EVAR was higher (HR: 1.2, 95% CI: 0.4-3.6; p = 0.754). According to the multivariable analysis, rupture (p = 0.045), female sex (p = 0.018), body weight (p = 0.003), and aortic size index (p = 0.019) were significant predictors of mortality, whereas OSR was not (p = 0.212). Conclusions: Treatment optimization requires a balanced approach, integrating both EVAR and OSR based on patient-specific factors. Maintaining expertise in both techniques is essential to ensure the best possible outcomes, and OSR should remain a viable option when clinically indicated.

Interferon stimulated gene 15 (ISG15) modulates phenotype of vascular smooth muscle cells and pathological vascular remodeling

INTRODUCTION

Inflammation is a major determinant of abdominal aortic aneurysms (AAA). Interferon stimulated gene 15 (ISG15) has a role in vascular remodelling in AAA. This study investigates the mechanisms whereby ISG15 might affect vascular remodeling and function.

METHODS

We used vascular smooth muscle cells (VSMC) from wild type (ISG15+/+) o ISG15 knockout (ISG15-/-) mice, aorta from ISG15+/+ and ISG15-/- mice infused with angiotensin II (1.44mg/kg/day, sc, 14 days), and human AAA. We also performed a model of recombinant ISG15 infusion (rISG15, sc, 100 and 500ng/day, 14 days) in mice.

RESULTS

In VSMC, ISG15 deficiency increased the expression of contractile (Acta2, Tagln) and synthetic (Fn1, Col1a2, Col3, Col4) markers and decreased the expression of the calcification marker Spp1. Ang II infusion changed the expression of phenotype markers differently in aorta from ISG15+/+ or ISG15-/- mice. ISG15 expression showed a negative correlation with expression of contractile markers (ACTA2, CNN1), and with COL3a1, in human samples from patients with AAA or with stenotic aorto-iliac pathology. rISG15 infusion induced hypotrophic vascular remodelling in mesenteric arteries without affecting vascular mechanics. Aorta of ISG15-/- mice contracted more to thromboxane A2 analogue U46619, compared to ISG15-/-mice. Both aorta and mesenteric arteries from rISG15-treated mice showed less contractility than control mice.

CONCLUSIONS

ISG15 participates in pathological vascular remodeling probably by modulating VSMC phenotype. These changes could also impact in the vascular function.

CIDEC/FSP27 exacerbates obesity-related abdominal aortic aneurysm by promoting perivascular adipose tissue inflammation

Abdominal aortic aneurysm (AAA) is strongly correlated with obesity, partially due to the abnormal expansion of abdominal perivascular adipose tissue (PVAT). Cell death-inducing DNA fragmentation factor-like effector C (CIDEC), also known as fat-specific protein 27 (FSP27) in rodents, is specifically expressed in adipose tissue where it mediates lipid droplet fusion and adipose tissue expansion. Whether and how CIDEC/FSP27 plays a role in AAA pathology remains elusive. Here, we show that FSP27 exacerbates obesity and angiotensin Ⅱ (Ang Ⅱ)-induced AAA progression. FSP27 deficiency in mice inhibited high-fat diet-induced PVAT expansion and inflammation. Both global and adipose tissue-specific FSP27 ablation significantly decreased obesity-related AAA incidence. Deficiency of FSP27 in adipocytes abrogated matrix metalloproteinase-12 (MMP12) expression in aortic tissues. Infiltrated macrophages, which partially colocalize with MMP12, were significantly decreased in the FSP27-deficient aorta. Mechanistically, knockdown of Fsp27 in 3T3-L1 adipocytes inhibited C-C motif chemokine ligand 2 (CCL2) expression and secretion through a c-Jun N-terminal kinase (JNK)-dependent pathway, thereby leading to reduced induction of macrophage migration, while Cidec overexpression rescued this effect. Overall, our study demonstrates that CIDEC/FSP27 in adipose tissue contributes to obesity-related AAA formation, at least in part, by enhancing PVAT inflammation and macrophage infiltration, thus shedding light on its significance as a key regulator in the context of obesity-related AAA.

Prediction of the need for surgery in patients with unruptured abdominal aortic aneurysm based on SOFA score

OBJECTIVE

This retrospective study aimed to explore the association and clinical value of sequential organ failure assessment (SOFA) score on the predictors of adverse events in patients with unruptured abdominal aortic aneurysms (AAA).

METHODS

A total of 322 patients from Medical Information Mart for Intensive Care IV database were enrolled. Logistic regression was conducted to explore the association between SOFA and primary outcome (need for surgery, NFS). Receiver operating characteristic (ROC) and nomogram analyses were used to assess its performance for predicting NFS. We also explored the association and clinical value of SOFA on secondary outcomes including hospital length of stay (LOS), ICU-LOS, and in-hospital mortality by linear and logistic regression analyses, generalized additive model, ROC, and decision curve analysis.

RESULTS

Totally 291 patients underwent the surgery. High SOFA score significantly correlated with NFS both in crude and adjusted models (all P<0.05). SOFA had a relatively favorable prediction performance on NFS (AUC = 0.701, 95%CI: 0.596-0.802). After adjusting for related diseases, its prediction performance was increased. When SOFA was combined with lactate and gender, the model showed an AUC of 0.888 (95%CI: 0.759-1.000) and 0.3-0.9 prediction possibility. Further, the SOFA also showed significant relationship with hospital-LOS, ICU-LOS, and in-hospital mortality (all P<0.05), and exerted some value in the prediction of 7-day hospital-LOS (AUC = 0.637, 95%CI: 0.575-0.686) and in-hospital mortality (AUC = 0.637, 95%CI: 0.680-0.845).

CONCLUSIONS

SOFA score was related to the NFS and can be regarded as a useful indicator for predicting the NFS in patients with AAA.

Integrative analysis of single-Cell RNA sequencing and experimental validation in the study of abdominal aortic aneurysm progression

BACKGROUND

Abdominal aortic aneurysm (AAA) is a complex vascular disorder characterized by the progressive dilation of the abdominal aorta, with a high risk of rupture and mortality. Understanding the cellular interactions and molecular mechanisms underlying AAA development is critical for identifying potential therapeutic targets.

METHODS

This study utilized datasets GSE197748, GSE164678 and GSE183464 from the GEO database, encompassing bulk and single-cell RNA sequencing data from AAA and control samples. We performed principal component analysis, differential expression analysis, and functional enrichment analysis to identify key pathways involved in AAA. Cell-cell interactions were investigated using CellPhoneDB, focusing on fibroblasts, vascular smooth muscle cells (VSMCs), and macrophages. We further validated our findings using a mouse model of AAA induced by porcine pancreatic enzyme infusion, followed by gene expression analysis and co-immunoprecipitation experiments.

RESULTS

Our analysis revealed significant alterations in gene expression profiles between AAA and control samples, with a pronounced immune response and cell adhesion pathways being implicated. Single-cell RNA sequencing data highlighted an increased proportion of pro-inflammatory macrophages, along with changes in the composition of fibroblasts and VSMCs in AAA. CellPhoneDB analysis identified critical ligand-receptor interactions, notably collagen type I alpha 1 chain (COL1A1)/COL1A2-CD18 and thrombospondin 1 (THBS1)-CD3, suggesting complex communication networks between fibroblasts and VSMCs. In vivo experiments confirmed the upregulation of these genes in AAA mice and demonstrated the functional interaction between COL1A1/COL1A2 and CD18.

CONCLUSION

The interaction between fibroblasts and VSMCs, mediated by specific ligand-receptor pairs such as COL1A1/COL1A2-CD18 and THBS1-CD3, plays a pivotal role in AAA pathogenesis.

Impact of Geometric Attributes on Abdominal Aortic Aneurysm Rupture Risk: An In Vivo FSI-Based Study

Reported in this paper is a cutting-edge computational investigation into the influence of geometric characteristics on abdominal aortic aneurysm (AAA) rupture risk, beyond the traditional measure of maximum aneurysm diameter. A Comprehensive fluid-structure interaction (FSI) analysis was employed to assess risk factors in a range of patient scenarios, with the use of three-dimensional (3D) AAA models reconstructed from patient-specific aortic data and finite element method. Wall shear stress (WSS), and its derivatives such as time-averaged WSS (TAWSS), oscillatory shear index (OSI), relative residence time (RRT) and transverse WSS (transWSS) offer insights into the force dynamics acting on the AAA wall. Emphasis is placed on these WSS-based metrics and seven key geometric indices. By correlating these geometric discrepancies with biomechanical phenomena, this study highlights the novel and profound impact of geometry on risk prediction. This study demonstrates the necessity of a multidimensional assessment approach, future efforts should complement these findings with experimental validations for an applicable approach for clinical use.

Nonlinear biomechanical behaviour of extracranial carotid artery aneurysms in the framework of Windkessel effect via FSI technique

Extracranial carotid artery aneurysms (ECCA) lead to rupture and neurologic symptoms from embolisation, with potentially fatal outcomes. Investigating the biomechanical behaviour of EECA with blood flow dynamics is crucial for identifying regions more susceptible to rupture. A coupled three-dimensional (3D) Windkessel-framework and hyperelastic fluid-structure interaction (FSI) analysis of ECCAs with patient-specific geometries, was developed in this paper with a particular focus on hemodynamic parameters and the arterial wall's biomechanical response. The blood flow has been modelled as non-Newtonian, pulsatile, and turbulent. The biomechanical characteristics of the aneurysm and artery are characterised employing a 5-parameter Mooney-Rivlin hyperelasticity model. The Windkessel effect is also considered to efficiently simulate pressure profile of the outlets and to capture the dynamic changes over the cardiac cycle. The study found the aneurysm carotid artery exhibited the high levels of pressure, wall shear stress (WSS), oscillatory shear index (OSI), and relative residence time (RRT) compared to the healthy one. The deformation of the arterial wall and the corresponding von Mises (VM) stress were found significantly increased in aneurysm cases, in comparison to that of no aneurysm cases, which strongly correlated with the hemodynamic characteristics of the blood flow and the geometric features of the aneurysms. This escalation would intensify the risk of aneurysm wall rupture. These findings have critical implications for enhancing treatment strategies for patients with extracranial aneurysms.

Local Morphologic and Hemodynamic Analyses for the Prediction of Abdominal Aortic Aneurysm Rupture Based on Patient-Specific CTA and Computational Modeling

OBJECTIVE

Extensive research has focused on the evaluation of rupture risks in abdominal aortic aneurysms (AAAs) through comprehensive morphologic and hemodynamic analyses, primarily considering the AAA as a whole entity. This study tried to identify the high-risk rupture sites of AAAs more precisely before the fatal process based on morphologic and hemodynamic analyses at the local segment.

METHODS

Computed tomography angiography of a specific AAA patient was conducted at the follow-up 4 months before rupture, 1 day before rupture, the day of the rupture, and 15 days after endovascular aortic repair. The evolution of local morphology and the hemodynamic characteristics at these critical timepoints were investigated based on patient-specific reconstructions and computational fluid dynamics.

RESULTS

The morphologic and hemodynamic parameters of the rupture region vary continuously in the process of AAA development and rupture. The surface area and volume of the rupture segment were gradually enlarged at the follow-up 4 months before rupture (47.33 cm2; 67.35 mL), 1 day before rupture (57.23 cm2; 85.24 mL), and on the day of the rupture (62.41cm2; 104.73ml). A prominent decrease in time-averaged wall shear stress and velocity for the rupture segment is observed. The percentages of the lowest time-averaged wall shear stress (<0.1 Pa) area are increased in the AAA region (20.42%, 33.85%, and 53.00%, separately).

CONCLUSIONS

The results based on precisely rebuilt geometries for the complete follow-ups of patient-specific computed tomography angiography demonstrate that notable morphologic and hemodynamic evolutions have occurred in the local segment of the AAA, which was further proved at the rupture site. The significant changes occurring at the local segment may provide valuable information for the evaluation of aneurysm rupture risk and locate the most probable site of rupture.

CLINICAL IMPACT

Capturing the entire process of AAA rupture through CTA imaging is a rare occurrence in clinical practice. The evolution of morphology and hemodynamic characteristics observed in the illustrated results provides valuable insights for clinicians to monitor the state of AAA from a different perspective. These findings suggest that variations in morphology and hemodynamics within the local segment of the AAA might serve as an alternative approach for predicting the rupture risk of AAA.

A bibliometric and visualization analysis of global trends and frontiers on macrophages in abdominal aortic aneurysms research

BACKGROUND

Macrophages are key regulators of the inflammatory and innate immune responses. Researchers have shown that aberrant expression of macrophages contributes to the development of abdominal aortic aneurysms (AAA). However, a comprehensive bibliometric analysis exploring the research status and knowledge mapping of this area is lacking. This study aimed to explore the research status, knowledge mapping and hotspots of macrophages in AAA research from a bibliometric perspective.

METHODS

In this study, we retrieved articles published between 2000 and 2022 on macrophages associated with AAA research from the Web of Science Core Collection (WoSCC) database. The retrieved literature data were further analyzed using Citespace and VOSviewer software.

RESULTS

A total of 918 qualified publications related to AAA-associated macrophages were retrieved. The number of publications in this field has been increasing annually. China and the United States were the 2 main drivers in this field, contributing to more than 64% of the publications. In addition, the US had the most publications, top institutions, and expert researchers, dominating in research on macrophages in AAA. The Harvard University was the most productive institution, with 60 publications. The journal with the most publications was Arteriosclerosis, Thrombosis, and Vascular Biology (86). Daugherty Alan was the most prolific author (28 publications) and he was also the most cited co- author. Furthermore, the exploration of established animal models, macrophage-related inflammatory-microenvironment, macrophage-related immune mechanism, clinical translation and molecular imaging research remained future research directions in this field.

CONCLUSIONS

Our findings offered new insights for scholars in this field. They will help researchers explore new directions for their work.

Vascular Impairment, Muscle Atrophy, and Cognitive Decline: Critical Age-Related Conditions

The triad of vascular impairment, muscle atrophy, and cognitive decline represents critical age-related conditions that significantly impact health. Vascular impairment disrupts blood flow, precipitating the muscle mass reduction seen in sarcopenia and the decline in neuronal function characteristic of neurodegeneration. Our limited understanding of the intricate relationships within this triad hinders accurate diagnosis and effective treatment strategies. This review analyzes the interrelated mechanisms that contribute to these conditions, with a specific focus on oxidative stress, chronic inflammation, and impaired nutrient delivery. The aim is to understand the common pathways involved and to suggest comprehensive therapeutic approaches. Vascular dysfunctions hinder the circulation of blood and the transportation of nutrients, resulting in sarcopenia characterized by muscle atrophy and weakness. Vascular dysfunction and sarcopenia have a negative impact on physical function and quality of life. Neurodegenerative diseases exhibit comparable pathophysiological mechanisms that affect cognitive and motor functions. Preventive and therapeutic approaches encompass lifestyle adjustments, addressing oxidative stress, inflammation, and integrated therapies that focus on improving vascular and muscular well-being. Better understanding of these links can refine therapeutic strategies and yield better patient outcomes. This study emphasizes the complex interplay between vascular dysfunction, muscle degeneration, and cognitive decline, highlighting the necessity for multidisciplinary treatment approaches. Advances in this domain promise improved diagnostic accuracy, more effective therapeutic options, and enhanced preventive measures, all contributing to a higher quality of life for the elderly population.

Investigating the effects of percutaneous endovascular aneurysm repair for abdominal aortic aneurysm on the lumen size of the common femoral artery

BACKGROUND

Percutaneous endovascular aneurysm repair (PEVAR) is the definitive therapy of choice for abdominal aortic aneurysms worldwide. However, current literature regarding the anatomic changes in the common femoral artery (CFA) post-PEVAR is sparse and contradictory, and a significant proportion of these studies did not control for the potential confounding effects of ethnicity. Thus, this study aims to investigate the anatomical effects of PEVAR on the CFA using an Asian study cohort.

METHODS

Between January 2019 and September 2023, the records of 113 patients who received PEVAR were reviewed. Groins with previous surgical interventions were excluded. The most proximate pre- and postoperative CT angiography of patients receiving PEVAR via the Perclose ProGlide™ Suture-Mediated Closure System were retrospectively analysed for changes in both the CFA inner luminal diameter (ID) and outer diameter (OD), the latter also encompassing the arterial walls. Access site complications within 3 months post-PEVAR were also recorded per patient.

RESULTS

One hundred seventeen groins from 60 patients were included in this study, with 1 report of pseudoaneurysm. The CFA ID exhibited a 0.167 mm decrease (p-value = 0.0403), while the OD decreased by 0.247 mm (p-value = 0.0107). This trend persisted when the data was separately analysed with the common cardiovascular risk factors of diabetes mellitus, hypertension and hyperlipidaemia.

CONCLUSION

Our analysis demonstrated a statistically significant decrease in the CFA diameters post-PEVAR. However, the percentage changes were below established flow-limiting values, as reflected by the single access site complication reported. Hence, our findings give confidence in the safety profile of this procedure, even with the reported smaller baseline CFA lumen size in Asians. Moving forward, similar longer-term studies should be considered to characterise any late postoperative effects.

The Role of Integrated Air Transport System in Managing Patients with Abdominal Aortic Aneurysm Rupture

OBJECTIVE

Ruptured abdominal aortic aneurysms (rAAAs) are highly morbid emergencies. Not all hospitals are equipped to repair them, and an air ambulance network may aid in regionalising specialty care to quaternary referral centres. The association between travel distance by air ambulance and rAAA mortality in patients transferred as an emergency for repair was examined.

METHODS

A retrospective review of institutional data. Adults with rAAA (2002 - 2019) transferred from an outside hospital (OSH) to a single quaternary referral centre for repair via air ambulance were identified. Patients who arrived via ground transport or post-repair at an OSH for continued critical care were excluded. Patients were divided into near and far groups based on the 75th percentile of the straight line travel distance (> 72 miles) between hospitals. The primary outcome was 30 day mortality. Multivariable logistic regression was used to assess the association between distance and mortality after adjusting for age, sex, ethnicity, cardiovascular comorbidities, and repair type.

RESULTS

A total of 290 patients with rAAA were transported a median distance of 40.4 miles (interquartile range 25.5, 72.7) with 215 (74.1%) near and 75 (25.9%) far patients. Both the near and far groups had similar ages, sex, and ethnicity. There was no difference in pre-operative loss of consciousness, intubation, or cardiac arrest between groups. Endovascular aneurysm repair utilisation and intra-operative aortic occlusion balloon use were also similar. Neither the observed (26.8% vs. 23.9%, p = .61) nor the adjusted odds ratio (0.70, 95% confidence interval 0.36 - 1.39, p = .32) 30 day mortality rate differed significantly between the near and far groups.

CONCLUSION

Increasing distance travelled during transfer by air ambulance was not associated with worse outcomes in patients with rAAA. The findings support the regionalisation of rAAA repair to large quaternary centres via an integrated and robust air ambulance network.

CTA-Based Radiomics and Area Change Rate Predict Infrarenal Abdominal Aortic Aneurysms Patients Events: A Multicenter Study

RATIONALE AND OBJECTIVES

Clinical assessment of abdominal aortic aneurysm (AAA) intervention and rupture risk relies primarily on maximum diameter, but studies have shown that sole dependence on diameter has limitations. CTA-based radiomics, aneurysm and lumen area change rates (AACR, LACR) are measured to predict potential AAA events.

MATERIALS AND METHODS

Between January 2017 and November 2022, 260 AAA patients from four centers who underwent two preoperative CTA examinations were included in this retrospective study. The endpoint event is defined as AAA rupture or repair. Patients were categorized into event and no-event groups based on the occurrence of endpoint event during follow-up. AACR and LACR were assessed using baseline and follow-up CTA, with radiomics features extracted from the baseline images. C-statistics and the Kaplan-Meier analysis were used to evaluate the predictive performance.

RESULTS

A total of 193 eligible infrarenal AAA patients were included, 176 (91.2%) were man and 17 (8.8%) were woman. The median follow-up was 33.4 (14.2, 57.4) months. Seven models were constructed, comprising the aneurysm-based Radscore model, lumen-based Radscore model, intraluminal thrombus (ILT)-based Radscore model, AACR model, LACR model, clinical model (including high-density lipoprotein, D-dimer, and baseline aneurysm diameter), and a merged model. On the external validation set, the C-index of seven models were 0.713 (0.574-0.853), 0.642 (0.499-0.786), 0.727 (0.600-0.854), 0.619 (0.484-0.753), 0.680 (0.530-0.830), 0.690 (0.557-0.824) and 0.760 (0.651-0.869), in that order. In the Kaplan-Meier analysis, the merged model was best-divided patients into high/low-risk groups with Log-rank p < 0.0001. The AARC and LARC between non-event and event groups have significant differences (AACR: 1.4 cm2/y vs. 2.3 cm2/y, p < 0.0001; LACR: 0.3 cm2/y vs. 1.1 cm2/y, p < 0.0001).

CONCLUSION

CTA-based radiomics, AACR and LACR have good predictive value for outcome event in infrarenal AAA patients.

NINJ1 Facilitates Abdominal Aortic Aneurysm Formation via Blocking TLR4-ANXA2 Interaction and Enhancing Macrophage Infiltration

Abdominal aortic aneurysm (AAA) is a common and potentially life-threatening condition. Chronic aortic inflammation is closely associated with the pathogenesis of AAA. Nerve injury-induced protein 1 (NINJ1) is increasingly acknowledged as a significant regulator of the inflammatory process. However, the precise involvement of NINJ1 in AAA formation remains largely unexplored. The present study finds that the expression level of NINJ1 is elevated, along with the specific expression level in macrophages within human and angiotensin II (Ang II)-induced murine AAA lesions. Furthermore, Ninj1flox/flox and Ninj1flox/floxLyz2-Cre mice on an ApoE-/- background are generated, and macrophage NINJ1 deficiency inhibits AAA formation and reduces macrophage infiltration in mice infused with Ang II. Consistently, in vitro suppressing the expression level of NINJ1 in macrophages significantly restricts macrophage adhesion and migration, while attenuating macrophage pro-inflammatory responses. Bulk RNA-sequencing and pathway analysis uncover that NINJ1 can modulate macrophage infiltration through the TLR4/NF-κB/CCR2 signaling pathway. Protein-protein interaction analysis indicates that NINJ1 can activate TLR4 by competitively binding with ANXA2, an inhibitory interacting protein of TLR4. These findings reveal that NINJ1 can modulate AAA formation by promoting macrophage infiltration and pro-inflammatory responses, highlighting the potential of NINJ1 as a therapeutic target for AAA.

Innovation in pathogenesis and management of aortic aneurysm

Aortic aneurysm (AA) refers to the persistent dilatation of the aorta, exceeding three centimeters. Investigating the pathophysiology of this condition is important for its prevention and management, given its responsibility for more than 25000 deaths in the United States. AAs are classified based on their location or morphology. various pathophysiologic pathways including inflammation, the immune system and atherosclerosis have been implicated in its development. Inflammatory markers such as transforming growth factor β, interleukin-1β, tumor necrosis factor-α, matrix metalloproteinase-2 and many more may contribute to this phenomenon. Several genetic disorders such as Marfan syndrome, Ehler-Danlos syndrome and Loeys-Dietz syndrome have also been associated with this disease. Recent years has seen the investigation of novel management of AA, exploring the implication of different immune suppressors, the role of radiation in shrinkage and prevention, as well as minimally invasive and newly hypothesized surgical methods. In this narrative review, we aim to present the new contributing factors involved in pathophysiology of AA. We also highlighted the novel management methods that have demonstrated promising benefits in clinical outcomes of the AA.

Comparative Analysis of Micro-Computed Tomography and 3D Micro-Ultrasound for Measurement of the Mouse Aorta

Aortic aneurysms, life-threatening and often undetected until they cause sudden death, occur when the aorta dilates beyond 1.5 times its normal size. This study used ultrasound scans and micro-computed tomography to monitor and measure aortic volume in preclinical settings, comparing it to the well-established measurement using ultrasound scans. The reproducibility of measurements was also examined for intra- and inter-observer variability, with both modalities used on 8-week-old C57BL6 mice. For inter-observer variability, the μCT (micro-computed tomography) measurements for the thoracic, abdominal, and whole aorta between observers were highly consistent, showing a strong positive correlation (R2 = 0.80, 0.80, 0.95, respectively) and no significant variability (p-value: 0.03, 0.03, 0.004, respectively). The intra-observer variability for thoracic, abdominal, and whole aorta scans demonstrated a significant positive correlation (R2 = 0.99, 0.96, 0.87, respectively) and low variability (p-values = 0.0004, 0.002, 0.01, respectively). The comparison between μCT and USS (ultrasound) in the suprarenal and infrarenal aorta showed no significant difference (p-value = 0.20 and 0.21, respectively). μCT provided significantly higher aortic volume measurements compared to USS. The reproducibility of USS and μCT measurements was consistent, showing minimal variance among observers. These findings suggest that μCT is a reliable alternative for comprehensive aortic phenotyping, consistent with clinical findings in human data.

Associations of Preoperative Nutritional Status and Sarcopenia With Mortality in Patients With Abdominal Aortic Aneurysm After Open and Endovascular Abdominal Aortic Aneurysm Repair: A Retrospective Study

OBJECTIVE

The effect of preoperative malnutrition and sarcopenia on outcomes in patients with abdominal aortic aneurysm (AAA) after open surgical repair (OSR) and endovascular abdominal aortic aneurysm repair is undefined. The authors conducted the study to address this issue in this population.

DESIGN

A retrospective observational study.

SETTING

A large tertiary hospital.

PARTICIPANTS

Patients with AAA who underwent OSR and endovascular aneurysm repair (EVAR).

INTERVENTIONS

Evaluation of nutritional status (Nutritional Risk Screening 2002 [NRS 2002] and the Controlling Nutritional Status [CONUT] scores), muscle size (skeletal muscle index), and postoperative parameters.

MEASUREMENTS AND MAIN RESULTS

A total of 199 patients were reviewed from January 2020 to December 2022. Patients weew categorized into group A (CONUT <4) and group B (CONUT ≥4) based on whether their CONUT scores were less than 4. The mortality (p = 0.004) and the incidence of Clavien-Dindo class III complications (p = 0.007) in group B were higher than those in group A. CONUT score was an independent risk factor for midterm mortality (hazard ratio 1.329; 95% CI, 1.104-1.697; p = 0.002) and Clavien-Dindo class III complications (odds ratio 1.225; 95% CI, 1.012-1.482; p = 0.037) according to univariate and multivariate analyses, whereas NRS 2002 score and sarcopenia were not. Kaplan-Meier curves showed a lower midterm survival rate in group B (log-rank p < 0.001).

CONCLUSION

In patients with AAA undergoing OSR or EVAR, a CONUT score ≥4 was associated with increased Clavien-Dindo class III complications and mortality. Preoperative nutritional status should be evaluated and optimized in this high-risk population.

N6-methyladenosine-associated genetic variants in NECTIN2 and HPCAL1 are risk factors for abdominal aortic aneurysm

Although N6-methyladenosine (m6A) modification has been implicated in the pathogenesis of abdominal aortic aneurysm (AAA), the relationship between m6A-associated single nucleotide polymorphisms (m6A-SNPs) and AAA remains unknown. This study used integrative multi-omics analysis and clinical validation approaches to systematically identify potential m6A-SNPs connected with AAA risk. We found that rs6859 and rs10198139 could modulate the expression of local genes, NECTIN2 and HPCAL1, respectively, which exhibited upregulation in AAA tissues, and their risk variants were significantly correlated with an increased susceptibility to AAA. Incorporating rs6859 and rs10198139 improved the efficiency of AAA risk prediction compared to the model considering only conventional risk factors. Additionally, these two SNPs were predicted to be located within the regulatory sequences, and rs6859 showed a substantial impact on m6A modification levels. Our findings suggest that m6A-SNPs rs6859 and rs10198139 confer an elevated risk of AAA, possibly by promoting local gene expression through an m6A-mediated manner.

The impact of dyslipidemia on prognosis of patients after endovascular abdominal aortic aneurysm repair

Introduction

Dyslipidemia is common in patients with abdominal aortic aneurysm (AAA). However, there is insufficient research on the impact of dyslipidemia on the postoperative outcomes of patients with AAA after endovascular aortic aneurysm repair (EVAR). This study aimed to determine the impact of dyslipidemia on the prognosis of patients with AAA treated with EVAR.

Method

We retrospectively reviewed patients with AAA who underwent EVAR at our hospital between 2010 and 2020. The baseline characteristics and prognoses of patients in the dyslipidemia and non-dyslipidemia groups were analyzed.

Results

A total of 641 patients were included; the prevalence of dyslipidemia in patients with AAA was 42.3% (271/641), and the mean follow-up time was 63.37 ± 26.49 months. The prevalence of diabetes (10.0% vs. 15.1%, P = 0.050), peripheral arterial disease (17.3% vs. 25.8%, P = 0.018), and chronic kidney disease (3.0% vs. 6.3%, P = 0.043) was higher in the dyslipidemia group. The three-year all-cause mortality rate after EVAR was 9.98% (64/641), and there was no difference in the incidence of all-cause mortality (10.27% vs. 9.59%, P = 0.778) between the two groups. A total of 36 (5.62%) major adverse cardiovascular and cerebrovascular events (MACCEs) were observed within 3 years and were more common in patients with dyslipidemia (2.97% vs. 9.59%, P < 0.001). The incidence of stent-related complications in all patients was 19.97% (128/641), and there was no difference in the incidence of stent-related complications between the two groups (22.16% vs. 16.97%, P = 0.105); however, the incidence of type I endoleak in the dyslipidemia group was lower than that in the non-dyslipidemia group (9.19% vs. 4.06%, P = 0.012). Cox-regression analysis showed that high level of high-density lipoprotein cholesterol (HDL-C) was the protective factor (HR, 0.203, 95% CI, 0.067-0.616, P = 0.005) for MACCES, but it was the risk factor for type I endoleak (HR, 2.317, 95% CI, 1.202-4.466, P = 0.012).

Conclusion

Dyslipidemia did not affect the mortality of patients with AAA who underwent EVAR; however, it may increase the incidence of MACCEs. Dyslipidemia may decrease the incidence of type I endoleaks after EVAR; however, further studies are warranted. We should strengthen the postoperative management of patients with dyslipidemia, prevent the occurrence of MACCEs.

Microwave Imaging System Based on Signal Analysis in a Planar Environment for Detection of Abdominal Aortic Aneurysms

A proof-of-concept of a microwave imaging system for the fast detection of abdominal aortic aneurysms is shown. This experimental technology seeks to overcome the factors hampering the fast screening for these aneurysms with the usual equipment, such as high cost, long-time operation or hazardous exposure to chemical substances. The hardware system is composed of 16 twin antennas mastered by a microcontroller through a switching network, which connects the antennas to the measurement instrument for sequential measurement. The software system is run by a computer, mastering the whole system, automatizing the measurement process and running the signal processing and medical image generation algorithms. Two image generation algorithms are tested: Delay-and-Sum (DAS) and Improved Delay-and-Sum (IDAS). Own-modified versions of these algorithms adapted to the requirements of our system are proposed. The system is carefully calibrated and fine-tuned with known objects placed at known distances. An experimental proof-of-concept is shown with a human torso phantom, including an aorta phantom and an aneurysm phantom placed in different positions. The results show good imaging capabilities with the potential for detecting and locating possible abdominal aortic aneurysms and reporting acceptable errors.

Doxycycline induces mitochondrial dysfunction in aortic smooth muscle cells

The antibiotic doxycycline is known to inhibit inflammation and was therefore considered as a therapeutic to prevent abdominal aortic aneurysm (AAA) growth. Yet mitochondrial dysfunction is a key-characteristic of clinical AAA disease. We hypothesize that doxycycline impairs mitochondrial function in the aorta and aortic smooth muscle cells (SMCs). Doxycycline induced mitonuclear imbalance, reduced proliferation and diminished expression of typical contractile smooth muscle cell (SMC) proteins. To understand the underlying mechanism, we studied krüppel-like factor 4 (KLF4). The expression of this transcription factor was enhanced in SMCs after doxycycline treatment. Knockdown of KLF4, however, did not affect the doxycycline-induced SMC phenotypic changes. Then we used the bioenergetics drug elamipretide (SS-31). Doxycycline-induced loss of SMC contractility markers was not rescued, but mitochondrial genes and mitochondrial connectivity improved upon elamipretide. Thus while doxycycline is anti-inflammatory, it also induces mitochondrial dysfunction in aortic SMCs and causes SMC phenotypic switching, potentially contributing to aortic aneurysm pathology. The drug elamipretide helps mitigate the harmful effects of doxycycline on mitochondrial function in aortic SMC, and may be of interest for treatment of aneurysm diseases with pre-existing mitochondrial dysfunction.

PINK1 dominated mitochondria associated genes signature predicts abdominal aortic aneurysm with metabolic syndrome

Abdominal aortic aneurysm (AAA) is typically asymptomatic but a devastating cardiovascular disorder, with overall mortality exceeding 80 % once it ruptures. Some patients with AAA may also have comorbid metabolic syndrome (MS), suggesting a potential common underlying pathogenesis. Mitochondrial dysfunction has been reported as a key factor contributing to the deterioration of both AAA and MS. However, the intricate interplay between metabolism and mitochondrial function, both contributing to the development of AAA, has not been thoroughly explored. In this study, we identified candidate genes related to mitochondrial function in AAA and MS. Subsequently, we developed a nomoscore model comprising hub genes (PINK1, ACSL1, CYP27A1, and SLC25A11), identified through the application of two machine learning algorithms, to predict AAA. We observed a marked disparity in immune infiltration profiles between high- and low-nomoscore groups. Furthermore, we confirmed a significant upregulation of the expression of the four hub genes in AAA tissues. Among these, ACSL1 showed relatively higher expression in LPS-treated RAW264.7 cell lines, while CYP27A1 exhibited a notable decrease. Moreover, SLC25A11 displayed a significant upregulation in AngII-treated VSMCs. Conversely, the expression level of PINK1 declined in LPS-stimulated RAW264.7 cell lines but significantly increased in AngII-treated VSMCs. In vivo experiments revealed that the activation of PINK1-mediated mitophagy inhibited the development of AAA in mice. In this current study, we have innovatively identified four mitochondrial function-related genes through integrated bioinformatic analysis. This discovery sheds light on the regulatory mechanisms and unveils promising therapeutic targets for the comorbidity of AAA and MS.

Multifunctional role of nanoparticles for the diagnosis and therapeutics of cardiovascular diseases

The increasing burden of cardiovascular disease (CVD) remains responsible for morbidity and mortality worldwide; their effective diagnostic or treatment methods are of great interest to researchers. The use of NPs and nanocarriers in cardiology has drawn much interest. The present comprehensive review provides deep insights into the use of current and innovative approaches in CVD diagnostics to offer practical ways to utilize nanotechnological interventions and the critical elements in the CVD diagnosis, associated risk factors, and management strategies of patients with chronic CVDs. We proposed a decision tree-based solution by discussing the emerging applications of NPs for the higher number of rules to increase efficiency in treating CVDs. This review-based study explores the screening methods, tests, and toxicity to provide a unique way of creating a multi-parametric feature that includes cutting-edge techniques for identifying cardiovascular problems and their treatments. We discussed the benefits and drawbacks of various NPs in the context of cost, space, time and complexity that have been previously suggested in the literature for the diagnosis of CVDs risk factors. Also, we highlighted the advances in using NPs for targeted and improved drug delivery and discussed the evolution toward the nano-cardiovascular potential for medical science. Finally, we also examined the mixed-based diagnostic approaches crucial for treating cardiovascular disorders, broad applications and the potential future applications of nanotechnology in medical sciences.

The future for the therapeutics of abdominal aortic aneurysm: engineered nanoparticles drug delivery for abdominal aortic aneurysm

Abdominal aortic aneurysm (AAA) is a severe cardiovascular disease with a high mortality rate. Several screening and diagnostic methods have been developed for AAA early diagnosis. Open surgery and endovascular aortic repair (EVAR) are clinically available for patients who meet the indications for surgery. However, for non-surgical patients, limited drugs exist to inhibit or reverse the progression of aneurysms due to the complex pathogenesis and biological structure of AAA, failing to accumulate precisely on the lesion to achieve sufficient concentrations. The recently developed nanotechnology offers a new strategy to address this problem by developing drug-carrying nanoparticles with enhanced water solubility and targeting capacity, prolonged duration, and reduced side effects. Despite the rising popularity, limited literature is available to highlight the progression of the field. Herein, in this review, we first discuss the pathogenesis of AAA, the methods of diagnosis and treatment that have been applied clinically, followed by the review of research progressions of constructing different drug-loaded nanoparticles for AAA treatment using engineered nanoparticles. In addition, the feasibility of extracellular vesicles (EVs) and EVs-based nanotechnology for AAA treatment in recent years are highlighted, together with the future perspective. We hope this review will provide a clear picture for the scientists and clinicians to find a new solution for AAA clinical management.

Disulfiram protects against abdominal aortic aneurysm by ameliorating vascular smooth muscle cells pyroptosis

PURPOSE

Recent studies demonstrated that pyroptosis is involved in abdominal aortic aneurysm (AAA) progression, suggesting a potential target for AAA treatment. This study aimed to identify if disulfiram could inhibit angiotensin II (Ang II)-induced vascular smooth muscle cells (VSMCs) damage, thereby exerting protective effects on AAA.

METHODS

The AAA mouse model was established by continuous subcutaneous Ang II infusion for 28 days. Then aortic tissue of the mice was isolated and subjected to RNA sequencing, qRT-PCR, Western blotting, and immunofluorescence staining. To explore the therapeutic effect of disulfiram, mice were orally administered disulfiram (50 mg/kg/day) or vehicle for 28 days accompanied with Ang II infusion. Pathological changes in aortic tissues were measured using microultrasound imaging analysis and histopathological analysis. In addition, inflammatory response, pyroptosis, and oxidative stress damage were examined in mouse aortic vascular smooth muscle (MOVAS) cells stimulated with Ang II in vitro.

RESULTS

The RNA sequencing and bioinformatic analysis results suggested that pyroptosis- and inflammation-related genes were significantly upregulated in AAA, consistent with the results of qRT-PCR and Western blotting. Most importantly, the therapeutic effect of disulfiram on AAA was identified in our study. First, disulfiram administration significantly attenuated Ang II-induced inflammation, pyroptosis, and oxidative stress in VSMCs, which is associated with the inhibition of the NF-κB-NLRP3 pathway. Second, in-vivo studies revealed that disulfiram treatment reduced AAA formation and significantly ameliorated collagen deposition and elastin degradation in the aortic wall.

CONCLUSION

Our findings suggest that disulfiram has a novel protective effect against AAA by inhibiting Ang II-induced VSMCs pyroptosis.

Association between the non-HDL-cholesterol to HDL- cholesterol ratio and abdominal aortic aneurysm from a Chinese screening program

BACKGROUND

Abdominal aortic aneurysms (AAAs) can result in high mortality upon rupture but are usually undiagnosed because of the absence of symptoms in the early stage. Ultrasound screening is regarded as an impactful way to prevent the AAA-related death but cannot be performed efficiently; therefore, a target population, especially in Asia, for this procedure is lacking. Additionally, although dyslipidaemia and atherosclerosis are associated with AAA. However, it remains undetermined whether the non-high-density lipoprotein-cholesterol to high-density lipoprotein-cholesterol ratio (NHHR) is associated with AAA. Therefore, this study was aimed at examining whether NHHR is associated with AAA.

METHOD

A total of 9559 participants who underwent AAA screening at Guangdong Provincial People's Hospital and through screening in two communities in Dongguan, from June 2019 to June 2021 joined in this screening program. The diagnosis of AAA was confirmed by the ultrasound examination of the abdominal aorta rather than any known or suspected AAA. Clinical and laboratory data of participants were collected. The participants were separated into a normal group and an AAA group according to the abdominal aortic status. To eliminate confounding factors, a propensity score matching (PSM) approach was utilized. The independent relationship between NHHR and AAA was assessed through the utilization of multivariable logistic regression analysis. In addition, internal consistency was evaluated through subgroup analysis, which controlled for significant risk factors.

RESULTS

Of all the participants, 219 (2.29%) participants were diagnosed with AAA. A significant elevation in NHHR was identified in the AAA group when contrasted with that in the normal group (P < 0.001). As demonstrated by the results of the multivariable logistic regression analysis, AAA was independently associated with NHHR before (odds ratio [OR], 1.440, P < 0.001) and after PSM (OR, 1.515, P < 0.001). Significant extension was observed in the areas under the receiver operating characteristic curves (AUROCs) of NHHR compared to those of single lipid parameters before and after PSM. An accordant association between NHHR and AAA in different subgroups was demonstrated by subgroup analysis.

CONCLUSION

In the Chinese population, there is an independent association between NHHR and AAA. NHHR might be propitious to distinguish individuals with high risk of AAA.

Brucella-infected abdominal aortic aneurysm: management strategies for an uncommon aneurysm

Objective

The occurrence of Brucella-induced abdominal aortic aneurysms is an exceedingly rare phenomenon, yet it stands as one of the most severe complications within this context. The combined utilization of serological testing and imaging diagnostics has been validated as an effective approach for the identification of Brucella-induced abdominal aortic aneurysms. Presently, the predominant therapeutic strategies encompass antibiotic treatment and surgical intervention. Nonetheless, ongoing controversies persist concerning the establishment of diagnostic criteria, the optimal timing and selection of antibiotic regimens, and the nuanced decision between open surgical procedures and endovascular interventions. Through a meticulous analysis of cases originating from our institution as well as a comprehensive review of previously documented instances, we aim to engage in a detailed discourse on the salient diagnostic and therapeutic facets surrounding Brucella-induced abdominal aortic aneurysms.

Methods

We conducted a retrospective summary of three cases involving Brucella-induced abdominal aortic aneurysms treated within our institution. Furthermore, we performed a comprehensive PubMed search, without imposing restrictions on language or publication year, to identify pertinent literature pertaining to Brucella-induced abdominal aortic aneurysms. The selection criteria primarily focused on case reports delineating occurrences of abdominal aortic aneurysms attributed to Brucella infection.

Results

We present three distinct cases of Brucella-induced abdominal aortic aneurysms managed at our institution, providing comprehensive insights into the employed diagnostic and therapeutic approaches. Additionally, over the past five decades, a total of 24 cases in 23 publications of Brucella-induced abdominal aortic aneurysms have been reported on PubMed. The earliest report dates back to 1976.

Conclusion

Our analysis suggests that Brucella-induced abdominal aortic aneurysm is characterized by a remarkably low incidence but is associated with a substantial risk of life-threatening complications. The integration of serological and imaging assessments assumes pivotal importance in facilitating prompt diagnosis of this condition. The prompt initiation of targeted antibiotic therapy is recommended, and the selection of appropriate surgical strategies should be guided by considerations including aneurysm dimensions and morphological attributes. The timely identification and intervention carry utmost significance in retarding disease advancement and ameliorating unfavorable clinical outcomes.

Early Progression of Abdominal Aortic Aneurysm is Decelerated by Improved Endothelial Barrier Function via ALDH2-LIN28B-ELK3 Signaling

The involvement of endothelial barrier function in abdominal aortic aneurysm (AAA) and its upstream regulators remains unknown. Single-cell RNA sequencing shows that disrupted endothelial focal junction is an early (3 days) and persistent (28 days) event during Angiotensin II (Ang II)-induced AAA progression. Consistently, mRNA sequencing on human aortic dissection tissues confirmed downregulated expression of endothelial barrier-related genes. Aldehyde dehydrogenase 2 (ALDH2), a negative regulator of AAA, is found to be upregulated in the intimal media of AAA samples, leading to testing its role in early-stage AAA. ALDH2 knockdown/knockout specifically in endothelial cells (ECs) significantly increases expression of EC barrier markers related to focal adhesion and tight junction, restores endothelial barrier integrity, and suppresses early aortic dilation of AAA (7 and 14 days post-Ang II). Mechanically, ELK3 acts as an ALDH2 downstream regulator for endothelial barrier function preservation. At the molecular level, ALDH2 directly binds to LIN28B, a regulator of ELK3 mRNA stability, hindering LIN28B binding to ELK3 mRNA, thereby depressing ELK3 expression and impairing endothelial barrier function. Therefore, preserving vascular endothelial barrier integrity via ALDH2-specific knockdown in ECs holds therapeutic potential in the early management of AAAs.

Evidence on the need for early identification of asymptomatic true abdominal aortic aneurysm in pregnancy: A case report

Pregnant women are more likely to face cardiovascular disease than non-pregnant women. However, abdominal aortic aneurysm is an extremely rare complication of pregnancy. Abdominal aortic aneurysms in pregnancy are difficult to identify in the early stage and are often diagnosed only when the symptoms have manifested. We report the case of a multiparous 35-year-old patient with a history of abnormal ascending aorta and ruled-out Marfan syndrome by genetic testing. After a multidisciplinary medical team evaluation, she delivered a live baby by cesarean section at 37 weeks of gestation, and the abdominal aortic aneurysm was repaired simultaneously. This case offers evidence-based recommendations for obstetricians to carry out preventive imaging examination for pregnant women with similar risk factors and provide successful experience in prenatal examination for similar diseases.

Swiss Vascular Biobank: Evaluation of Optimal Extraction Method and Admission Solution for Preserving RNA from Human Vascular Tissue

Proper biobanking is essential for obtaining reliable data, particularly for next-generation sequencing approaches. Diseased vascular tissues, having extended atherosclerotic pathologies, represent a particular challenge due to low RNA quality. In order to address this issue, we isolated RNA from vascular samples collected in our Swiss Vascular Biobank (SVB); these included abdominal aortic aneurysm (AAA), peripheral arterial disease (PAD), healthy aorta (HA), and muscle samples. We used different methods, investigated various admission solutions, determined RNA integrity numbers (RINs), and performed expression analyses of housekeeping genes (ACTB, GAPDH), ribosomal genes (18S, 28S), and long non-coding RNAs (MALAT1, H19). Our results show that RINs from diseased vascular tissue are low (2-4). If the isolation of primary cells is intended, as in our SVB, a cryoprotective solution is a better option for tissue preservation than RNAlater. Because RNA degradation proceeds randomly, controls with similar RINs are recommended. Otherwise, the data might convey differences in RNA degradation rather than the expressions of the corresponding genes. Moreover, since the 18S and 28S genes in the diseased vascular samples were degraded and corresponded with the low RINs, we believe that DV200, which represents the total RNA's disintegration state, is a better decision-making aid in choosing samples for omics analyses.

Effects of miR-33 Deficiency on Metabolic and Cardiovascular Diseases: Implications for Therapeutic Intervention

MicroRNAs (miRNAs) are small noncoding RNAs that post-transcriptionally inhibit gene expression. These small molecules are involved in several biological conditions such as inflammation, cell growth and proliferation, and regulation of energy metabolism. In the context of metabolic and cardiovascular diseases, miR-33 is of particular interest as it has been implicated in the regulation of lipid and glucose metabolism. This miRNA is located in introns harboured in the genes encoding sterol regulatory element-binding protein (SREBP)-1 and SREBP-2, which are key transcription factors involved in lipid biosynthesis and cholesterol efflux. This review outlines the role of miR-33 in a range of metabolic and cardiovascular pathologies, such as dyslipidaemia, nonalcoholic fatty liver disease (NAFLD), obesity, diabetes, atherosclerosis, and abdominal aortic aneurysm (AAA), and it provides discussion about the effectiveness of miR-33 deficiency as a possible therapeutic strategy to prevent the development of these diseases.

Rivaroxaban in patients with abdominal aortic aneurysm and high-sensitivity C-reactive protein elevation (BANBOO): study protocol for a randomized, controlled trial

BACKGROUND

Abdominal aortic aneurysm (AAA) is a fatal disease due to the tendency to rupture. The drug treatment for small AAA without surgical indications has been controversial. Previous studies showed that high-sensitivity C-reactive protein (hs-CRP) had become a potential biomarker of the disease, and the anti-inflammatory effect of rivaroxaban for AAA had been well established. Thus, we hypothesized that rivaroxaban could control the progression of AAA in patients with hs-CRP elevation.

METHODS

The study is a prospective, open-label, randomized, controlled clinical trial. Sixty subjects are recruited from the General Hospital of Northern Theatre Command of China. Subjects are randomly assigned (1:1) to the intervention arm (rivaroxaban) or control arm (aspirin). The primary efficacy outcome is the level of serum hs-CRP at 6 months. The secondary outcomes include imaging examination (the maximal diameter of AAA, the maximal thickness of mural thrombus, and the length of aneurysm), major adverse cardiovascular and cerebrovascular events (MACCE, including AAA transformation, non-fatal myocardial infarction, acute congestive heart failure, stent thrombosis, ischemia-driven target vessel revascularization, vascular amputation, stroke, cardiovascular death, and all-cause death), and other laboratory tests (troponin T, interleukin 6, D-dimer, and coagulation function).

DISCUSSION

The BANBOO trial tested the effect of rivaroxaban on the progression of AAA in patients with elevated Hs-CRP for the first time.

TRIAL REGISTRATION

ChiCTR2100051990, ClinicalTrials.gov, registered on 12 October 2021.

Vascular Biology of arterial aneurysms

OBJECTIVE

This review aims to analyze biomolecular and cellular events responsible for arterial aneurysm formation with particular attention to vascular remodeling that determines the initiation and the progression of arterial aneurysm, till rupture.

METHODS

This review was conducted searching libraries such as Web of Science, Scopus, ScienceDirect and Medline. Used keywords with various combinations were: "arterial aneurysms", "biology", "genetics", "proteomics", "molecular", "pathophysiology" and extracellular matrix" RESULTS: There are several genetic alterations responsible of syndromic and non-syndromic disease that predispose to aneurysm formation. ECM imbalance, mainly due to the alteration of vascular smooth muscle cells (VSMCs) homeostasis, overexpression of metalloproteinases (MPs) and cytokines activation, determines weakness of the arterial wall that dilates thus causing aneurysmal disease. Altered mechanotransduction in the ECM may also trigger and sustain anomalous cellular and biochemical signaling. Different cell population such as VSMCs, macrophages, perivascular adipose tissue (PVAT) cells, vascular wall resident stem cells (VWRSCs) are all involved at different levels CONCLUSIONS: Improving knowledge in vascular biology may help researchers and physicians in better targeting aneurysmal disease in order to better prevent and better treat such important disease.

The impact of neighborhood social disadvantage on abdominal aortic aneurysm severity and management

OBJECTIVE

Recent studies have highlighted socioeconomic disparities in the severity and management of abdominal aortic aneurysm (AAA) disease. However, these studies focus on individual measures of social disadvantage such as income and insurance status. The area deprivation index (ADI), a validated measure of neighborhood deprivation, provides a more comprehensive assessment of social disadvantage. Therefore, we examined the impact of ADI on AAA severity and its management.

METHODS

We identified all patients who underwent endovascular or open repair of an AAA in the Vascular Quality Initiative registry between 2003 and 2020. An ADI score of 1 to 100 was assigned to each patient based on their residential zip code, with higher ADI scores corresponding with increasing deprivation. Patients were categorized by ADI quintiles. Outcomes of interest included rates of ruptured AAA (rAAA) repair versus an intact AAA repair and rates of endovascular repair (EVAR) versus the open approach. Logistic regression was used to evaluate for an independent association between ADI quintile and these outcomes.

RESULTS

Among 55,931 patients who underwent AAA repair, 6649 (12%) were in the lowest ADI quintile, 11,692 (21%) in the second, 15,958 (29%) in the third, 15,035 (27%) in the fourth, and 6597 (12%) in the highest ADI quintile. Patients in the two highest ADI quintiles had a higher proportion of rAAA repair (vs intact repair) compared with those in the lowest ADI quintile (8.8% and 9.1% vs 6.2%; P < .001). They were also less likely to undergo EVAR (vs open approach) when compared with the lowest ADI quintile (81% and 81% vs 88%; P < .001). There was an overall trend toward increasing rAAA and decreasing EVAR rates with increasing ADI quintiles (P < .001). In adjusted analyses, when compared with patients in the lowest ADI quintile, patients in the highest ADI quintile had higher odds of rAAA repair (odds ratio, 1.4; 95% confidence interval, 1.2-1.8; P < .001) and lower odds of undergoing EVAR (odds ratio, 0.54; 95% confidence interval, 0.45-0.65; P < .001).

CONCLUSIONS

Among patients who underwent AAA repair in the Vascular Quality Initiative, those with higher neighborhood deprivation had significantly higher rates of rAAA repair (vs intact repair) and lower rates of EVAR (vs open approach). Further work is needed to better understand neighborhood factors that are contributing to these disparities to identify community-level targets for improvement.

The SNP rs4591246 in pri-miR-1-3p is associated with abdominal aortic aneurysm risk by regulating cell phenotypic transformation via the miR-1-3p/TLR4 axis

Emerging evidence reveals that single nucleotide polymorphism (SNP) within miRNAs can affect the risk of cardiovascular diseases. However, the role of miRNA SNPs in abdominal aortic aneurysm (AAA) is unclear. This study aimed to determine the association between SNPs in pri-miR-1-3p and AAA risk, as well as its underlying molecular mechanism. SNP genotyping was performed in 335 AAA patients and 335 controls using the KASP method and tissue miR-1-3p expression was measured by qRT-PCR. The biological effects of significant SNP were validated using in vitro studies. We found that the rs4591246 variant genotype was correlated with increased AAA risk and tissue miR-1-3p expression was reduced in AAA patients as compared with control subjects. An in silico approach predicted that the rs4591246 polymorphism altered the secondary structure and stability of pri-miR-1-3p, and in vitro evidence suggested that the rs4591246 polymorphism affected mature miR-1-3p expression. And luciferase assays verified TLR4 as a direct target gene of miR-1-3p. Further functional experiments demonstrated that the rs4591246 variant genotype could promote Ang II-induced cell phenotypic switching by suppressing mature miR-1-3p expression and in turn upregulating TLR4 expression, but this effect was rescued in the presence of TLR4 siRNA. In conclusion, as a promising genetic biomarker for AAA susceptibility, the SNP rs4591246 may exert its effects on AAA risk by regulating cell phenotypic transformation via the miR-1-3p/TLR4 axis.

Abdominal aortic aneurysm growth rates in patients undergoing local ultrasound surveillance

Objectives

Abdominal aortic aneurysm ultrasound surveillance varies between hospitals in the United Kingdom. University Hospitals Bristol and Weston adopt a 6-monthly surveillance interval for 4.5-4.9 cm abdominal aortic aneurysm, which is a deviation from nationally recommended 3-monthly intervals. Assessment of abdominal aortic aneurysm growth rate, and the concurrent impact of abdominal aortic aneurysm risk factors and medications prescribed for risk factors, may inform whether this change in surveillance intervals is safe and appropriate.

Methods

This analysis was conducted retrospectively. A total of 1312 abdominal aortic aneurysm ultrasound scans from 315 patients between January 2015 and March 2020 were split into 0.5 cm groups, ranging from 3.0 to 5.5 cm. Abdominal aortic aneurysm growth rate was assessed with one-way analysis of variance. The impact of risk factors and risk factor medication on abdominal aortic aneurysm growth rate was analysed using multivariate and univariate linear regression and Kruskal-Wallis tests. Patient cause of death among surveillance patients was recorded.

Results

Abdominal aortic aneurysm growth rate was significantly associated with increased abdominal aortic aneurysm diameter (p < 0.001). There was a significant whole-group reduction in growth rate from 0.29 to 0.19 cm/year in diabetics compared to non-diabetics (p = 0.02), supported by univariate linear regression (p = 0.04). In addition, gliclazide patients had lower growth rate compared to patients not on the medication (p = 0.04). One abdominal aortic aneurysm rupture occurred <5.5 cm resulting in death.

Conclusion

Abdominal aortic aneurysm measuring 4.5-4.9 cm had a mean growth rate of 0.3 cm/year (± 0.18 cm/year). Therefore, mean growth rate and variability suggest patients are unlikely to surpass surgical threshold of 5.5 cm between the 6-monthly surveillance scans, supported by low rupture rates. This suggests the surveillance interval for 4.5-4.9 cm abdominal aortic aneurysm is a safe and appropriate deviation from national guidance. In addition, it may be pertinent to consider diabetic status when designing surveillance intervals.

Anaesthesia for vascular emergencies - a state of the art review

In this state-of-the-art review, we discuss the presenting symptoms and management strategies for vascular emergencies. Although vascular emergencies are best treated at a vascular surgical centre, patients may present to any emergency department and may require both immediate management and safe transport to a vascular centre. We describe the surgical and anaesthetic considerations for management of aortic dissection, aortic rupture, carotid endarterectomy, acute limb ischaemia and mesenteric ischaemia. Important issues to consider in aortic dissection are extent of the dissection and surgical need for bypasses in addition to endovascular repair. From an anaesthetist's perspective, aortic dissection requires infrastructure for massive transfusion, smooth management should an endovascular procedure require conversion to an open procedure, haemodynamic manipulation during stent deployment and prevention of spinal cord ischaemia. Principles in management of aortic rupture, whether open or endovascular treatment is chosen, include immediate transfer to a vascular care centre; minimising haemodynamic changes to reduce aortic shear stress; permissive hypotension in the pre-operative period; and initiation of massive transfusion protocol. Carotid endarterectomy for carotid stenosis is managed with general or regional techniques, and anaesthetists must be prepared to manage haemodynamic, neurological and airway issues peri-operatively. Acute limb ischaemia is a result of embolism, thrombosis, dissection or trauma, and may be treated with open repair or embolectomy, under either general or local anaesthesia. Due to hypercoagulability, there may be higher numbers of acutely ischaemic limbs among patients with COVID-19, which is important to consider in the current pandemic. Mesenteric ischaemia is a rare vascular emergency, but it is challenging to diagnose and associated with high morbidity and mortality. Several peri-operative issues are common to all vascular emergencies: acute renal injury; management of transfusion; need for heparinisation and reversal; and challenging postoperative care. Finally, the important development of endovascular techniques for repair in many vascular emergencies has improved care, and the availability of transoesophageal echocardiography has improved monitoring as well as aids in surgical placement of endovascular grafts and for post-procedural evaluation.

High-Strength Injectable Hydrogel into Perivascular Interstitial Space Enhances Arterial Adventitial Stress

Injectable hydrogels with strong mechanical properties have significant potential for biomedical applications, including the development of electronic skin, intelligent medical robots, as well as tissue engineering. In this study, we report on an injectable hydrogel with notable tensile strength and adhesion properties, achieved through cross-linking thiol-terminated four-arm poly (ethylene glycol) using silver-doped nano-hydroxyapatite, modified with dopamine. Subsequently, the hydrogel was injected in vivo through the perivascular interstitial space of rats. The hydrogel wrapped around the damaged abdominal aortic adventitia, which greatly increases the stress strength of the arterial adventitia. We found that the hydrogel was characterized by excellent biocompatibility, and it induced little immune response over a span of 21 days post-implantation. This simple and minimally invasive vascular protection strategy appears promising for the treatment of vascular diseases, such as abdominal aortic aneurysm (AAA).