Abdominal Aortic Aneurysm Group Research Articles

Diagnostic value of uric acid to high-density lipoprotein cholesterol ratio in abdominal aortic aneurysms

Background Abdominal aortic aneurysm (AAA) is highly lethal upon onset of acute aortic diseases (AAD) or rupture. Dyslipidaemia and hyperuricaemia are important risk factors for the development of AAA and AAD as well as aortic disease-related death. The aim of this study was to explore whether uric acid (UA) to high-density lipoprotein cholesterol (HDL-C) ratio (UHR) can be used as an independent predictor of the presence of AAA or AAD. Methods Three hundred subjects, including 100 AAA patients (AAA group), 100 AAD patients (AAD group) and 100 controls (CON group), were recruited in this study. UHR and other serum samples were obtained upon the patients’ admission before any medical treatment. The optimal cut-off points of UHR were determined using receiver operating characteristic (ROC) curve analysis. Results The UHR in AAA group was significantly higher than that in CON group, but there was no significant difference between AAD group and CON group. The optimal cut-off point of UHR for AAA was 7.78 (sensitivity 84.7%, specificity 62.4%, and AUC 0.811; p < 0.001), and UHR (OR: 1.122, 95%CI: 1.064-1.184; p < 0.001) was found to be an independent factor for predicting AAA after adjusting for traditional AAA risk factor. Conclusion UHR can be widely used in clinical practice as an auxiliary tool for screening AAA. The optimal cut-off point for UHR to AAA was determined for the first time in Chinese subjects.

Biomechanical Characterization of Abdominal Aortic Aneurysm: The Rupture Mechanism

In this work, a four-week-old male C57Bl/6 mouse model of abdominal aortic aneurysm (AAA) was developed to examine the AAA rupture mechanism. Immunofluorescence staining was adopted for quantifying the degradation of elastin, and Picrosirius Red staining was adopted for evaluating the density of collagen. Atomic force microscopy with two probe tip sizes of 5 µm and 20 nm was adopted for mechanical characterization of the AAA. The microstructure changes and stiffness changes in both AAA samples and controlled samples were inspected. The degradation of elastin, wall thickening, formation of micro vessels, and increased density of collagen were observed in the AAA samples. The AAA samples also exhibited fragmented texture from AFM scanning. The histogram of stiffness measurements of the AAA samples with a 20 nm tip demonstrated two unique peak frequencies of stiffness intervals (0–10 kPa and 40–50 kPa). The stiffer regions were correlated with the increased density of collagen, as shown in the immunofluorescence images. The softer regions, combined with the fragmented texture, could be the key index contributing to the initiation and propagation of AAA rupture. Overall, the AAA group showed a higher stiffness than the control group (50.77 ± 62.4 kPa vs. 40.6 ± 51.86 kPa). The findings from this work may help in explaining ruptures in small AAA (&lt;5.5 mm), which account for ten percent of all AAA ruptures. Additionally, the observations in this study may help develop early detection methods and innovative treatments for AAA.

Systematic Review and Meta-Analysis of the Incidence of Rupture, Repair, and Death of Small and Large Abdominal Aortic Aneurysms under Surveillance.

The ultimate goal of treating patients with abdominal aortic aneurysms (AAAs) is to repair them when the risk of rupture exceeds the risk of repair. Small AAAs demonstrate a low rupture risk, and recently, large AAAs just above the threshold (5.5-6.0 cm) seem to be at low risk of rupture as well. The present review aims to investigate the outcomes of AAAs under surveillance through a comprehensive systematic review and meta-analysis. PubMed, Embase, and the Cochrane Central Register were searched (22 March 2022; PROSPERO; #CRD42022316094). The Cochrane and PRISMA statements were respected. Blinded systematic screening of the literature, data extraction, and quality assessment were performed by two authors. Conflicts were resolved by a third author. The meta-analysis of prevalence provided estimated proportions, 95% confidence intervals, and measures of heterogeneity (I2). Based on I2, the heterogeneity might be negligible (0-40%), moderate (30-60%), substantial (50-90%), and considerable (75-100%). The primary outcome was the incidence of AAA rupture. Secondary outcomes included the rate of small AAAs reaching the threshold for repair, aortic-related mortality, and all-cause mortality. Fourteen publications (25,040 patients) were included in the analysis. The outcome rates of the small AAA group (<55 mm) were 0.3% (95% CI 0.0-1.0; I2 = 76.4%) of rupture, 0.6% (95% CI 0.0-1.9; I2 = 87.2%) of aortic-related mortality, and 9.6% (95% CI 2.2-21.1; I2 = 99.0%) of all-cause mortality. During surveillance, 21.4% (95% CI 9.0-37.2; I2 = 99.0%) of the initially small AAAs reached the threshold for repair. The outcome rates of the large AAA group (>55 mm) were 25.7% (95% CI 18.0-34.3; I2 = 72.0%) of rupture, 22.1% (95% CI 16.5-28.3; I2 = 25.0%) of aortic-related mortality, and 61.8% (95% CI 47.0-75.6; I2 = 89.1%) of all-cause mortality. The sensitivity analysis demonstrated a higher rupture rate in studies including <662 subjects, patients with a mean age > 72 years, >17% of female patients, and >44% of current smokers. The rarity of rupture and aortic-related mortality in small AAAs supports the current conservative management of small AAAs. Surveillance seems indicated, as one-fifth reached the threshold for repair. Large aneurysms had a high incidence of rupture and aortic-related mortality. However, these data seem biased by the sparse and heterogeneous literature overrepresented by patients unfit for surgery. Specific rupture risk stratified by age, gender, and fit-for-surgery patients with large AAAs needs to be further investigated.

A Ratio Between Infrarenal and Suprarenal Aortic Diameters Corrects for Absolute Aortic Diameter Variations due to Patients' Sex and Body Size.

Aortic diameters may differ significantly between patients with different gender and body size. The aim of this study was to relate absolute aortic diameters to age, sex, height, and weight of the patients and to correct for these factors by calculating the ratio between the infrarenal and the suprarenal aortic diameters. A total of 458 patients who underwent elective endovascular aneurysm repair (EVAR) between 2004 and 2018 were included. The aortic anatomy in this group of elective EVAR patients was compared with a control group of 75 patients without an abdominal aortic aneurysm (AAA). The aortic diameter was measured at 4 suprarenal points and 4 infrarenal points. Ratios were calculated by dividing the mean infrarenal neck diameter by 4 suprarenal measurements. Patients in the aneurysm group had significantly larger suprarenal and infrarenal aortic diameters. The ratios between the mean infrarenal neck diameter and all 4 suprarenal measurements were larger in the AAA group than in the control group. In both groups, there was a significant correlation between the mean infrarenal neck diameter and sex, height, weight, and body surface area (BSA). However, in both groups, all 4 ratios between the mean infrarenal neck diameter and suprarenal aortic diameters were not correlated with age, sex, height, weight, or BSA, except for the ratio between the mean infrarenal neck diameter and the aortic diameter measurement proximal to the upper renal artery, which was correlated to weight and BSA in the control group. The mean infrarenal neck diameter is correlated with sex, height, weight, and BSA. However, when the suprarenal aortic diameter was used as an internal control for the mean infrarenal neck diameter, we were able to correct for these variations in aortic diameters due to sex and body size. The clinical relevance of this ratio in patients treated by EVAR has yet to be assessed in future research. In the assessment for EVAR suitability the absolute diameter of the aneurysm neck is taken into account. We believe that using absolute diameters is not the appropriate way to assess this suitability, but that patient characteristics such as age, gender and body size, should be factored into this assessment. In this paper, we show that suprarenal and infrarenal aortic diameters are both significantly increased in patients with an aneurysm compared with patients without an aneurysm. Besides, we found that mean infrarenal aortic diameter is correlated with sex, height, weight, and body surface area. Finally, we propose a new ratio system, using suprarenal diameters as an internal control, to correct for aortic diameter variations due to sex and body size.

Association of Genetic Polymorphisms with Abdominal Aortic Aneurysm in the Processes of Apoptosis, Inflammation, and Cholesterol Metabolism.

Background and Objectives: This study aims to identify the minor allele of the single nucleotide polymorphisms (SNPs) DAB2IP rs7025486, IL6R rs2228145, CDKN2BAS rs10757278, LPA rs3798220, LRP1 rs1466535, and SORT1 rs599839 in order to assess the risk of abdominal aortic aneurysm (AAA) formation and define the linkage among these SNPs. Materials and Methods: A case-control study with AAA patients (AAA group) and non-AAA controls (control group) was carried out in a study population. DNA was isolated from whole blood samples; the SNPs were amplified using PCR and sequenced. Results: In the AAA group of 148 patients, 87.2% of the patients were male, 64.2% had a history of smoking, and 18.2% had relatives with AAA. The mean ± SD of age, BMI, and aneurysmal diameter in the AAA group were 74.8 ± 8.3 years, 27.6 ± 4.6 kg/m2, and 56.2 ± 11.8 mm, respectively. In comparison with 50 non-AAA patients, there was a significantly elevated presence of the SNPs DAB2IP rs7025486[A], CDKN2BAS rs10757278[G], and SORT1 rs599839[G] in the AAA group (p-values 0.040, 0.024, 0.035, respectively), while LPA rs3798220[C] was significantly higher in the control group (p = 0.049). A haplotype investigation showed that the SNPs DAB2IP, CDKN2BAS, and IL6R rs2228145[C] were significantly elevated in the AAA group (p = 0.037, 0.037, and 0.046) with minor allele frequencies (MAF) of 25.5%, 10.6%, and 15.4%, respectively. Only DAB2IP and CDKN2BAS showed significantly higher occurrences of a mutation (p = 0.028 and 0.047). Except for LPA, all SNPs were associated with a large aortic diameter in AAA (p < 0.001). Linkage disequilibrium detection showed that LPA to DAB2IP, to IL6R, to CDKN2BAS, and to LRP1 rs1466535[T] had D' values of 70.9%, 80.4%, 100%, and 100%, respectively. IL6R to LRP1 and to SORT1 had values for the coefficient of determination (r2) of 3.9% and 2.2%, respectively. Conclusions: In the investigated study population, the SNPs CDKN2BAS rs10757278, LPA rs3798220, SORT1 rs599839, DAB2IP rs7025486, and IL6R rs2228145 were associated with the development of abdominal aortic aneurysms. Individuals with risk factors for atherosclerosis and/or a family history of AAA should be evaluated using genetic analysis.

Regional and Global Aortic Pulse Wave Velocity in Patients with Abdominal Aortic Aneurysm

Abdominal aortic aneurysm (AAA) is commonly defined as a localised dilatation with a diameter > 30 mm. The pathophysiology of AAA includes chronic inflammation and enzymatic degradation of elastin, possibly increasing aortic wall stiffness and pulse wave velocity (PWV). Whether aortic stiffness is more prominent in the abdominal aorta at the aneurysm site is not elucidated. The aim of this study was to evaluate global and regional aortic PWV in patients with AAA. Experimental study of local PWV in the thoracic descending and abdominal aorta in patients with AAA and matched controls. The study cohort comprised 25 patients with AAA > 30 mm (range 36 - 70 mm, all male, age range 65 - 76 years) and 27 age- and sex-matched controls free of AAA. PWV was measured with applanation tonometry (carotid-femoral PWV, cfPWV) as well as 4D flow MRI technique, assessing regional aortic PWV. Blood pressure and anthropometrics were measured. Global aortic PWV was greater in men with AAA than controls, both by MRI (AAA 8.9 ± 2.4 m/s vs. controls 7.1 ± 1.5 m/s; p = .007) and cfPWV (AAA 11.0 ± 2.1 m/s vs. controls 9.3 ± 2.3 m/s; p = .007). Regionally, PWV was greater in the abdominal aorta in the AAA group (AAA 7.0 ± 1.8 m/s vs. controls 5.8 ± 1.0 m/s; p = .022), but similar in the thoracic descending aorta (AAA 8.7 ± 3.2 m/s vs. controls 8.2 ± 2.4 m/s; p = .59). Furthermore, PWV was positively associated with indices of central adiposity both in men with AAA and controls. PWV is higher in men with AAA compared with matched controls in the abdominal but not the thoracic descending aorta. Furthermore, aortic stiffness was linked with central fat deposition. It remains to be seen whether there is a causal link between AAA and increased regional aortic stiffness.

Dysregulations of Key Regulators of Angiogenesis and Inflammation in Abdominal Aortic Aneurysm.

Abdominal aortic aneurysm (AAA) is a chronic vascular disease caused by localized weakening and broadening of the abdominal aorta. AAA is a clearly underdiagnosed disease and is burdened with a high mortality rate (65-85%) from AAA rupture. Studies indicate that abnormal regulation of angiogenesis and inflammation contributes to progression and onset of this disease; however, dysregulations in the molecular pathways associated with this disease are not yet fully explained. Therefore, in our study, we aimed to identify dysregulations in the key regulators of angiogenesis and inflammation in patients with AAA in peripheral blood mononuclear cells (using qPCR) and plasma samples (using ELISA). Expression levels of ANGPT1, CXCL8, PDGFA, TGFB1, VEGFB, and VEGFC and plasma levels of TGF-alpha, TGF-beta 1, VEGF-A, and VEGF-C were found to be significantly altered in the AAA group compared to the control subjects without AAA. Associations between analyzed factors and risk factors or biochemical parameters were also explored. Any of the analyzed factors was associated with the size of the aneurysm. The presented study identified dysregulations in key angiogenesis- and inflammation-related factors potentially involved in AAA formation, giving new insight into the molecular pathways involved in the development of this disease and providing candidates for biomarkers that could serve as diagnostic or therapeutic targets.

Eleven-Year Outcomes of a Screening Project for Abdominal Aortic Aneurysm (AAA) in 65-Year-Old Men.

Since 2011, the Department of Vascular Surgery at Oslo University Hospital has offered screening for abdominal aortic aneurysm (AAA) to 65-year-old men living in Oslo, Norway. The aim of this study was to evaluate the effect of the screening project on AAA-related mortality and rupture and repair rates in the screened population. This cohort study included men that participated in AAA screening at the Department of Vascular Surgery at Oslo University Hospital in the period May 2011 to September 2019. All men with screen-detected AAA (aortic diameter ≥30 mm) and subaneurysmal aortic dilatation (aortic diameter 25-29 mm) were included. A stratified (1:1 with the subaneurysm group), randomized selection of men with normal aortic diameter (<25 mm) upon screening was also included. The follow-up data on events (ruptures, repairs, and deaths) after screening were collected retrospectively from patient electronic medical records at Oslo University Hospital, the National Population Register and the Norwegian Cause of Death Registry (CoDR). In total, 2048 men were included, with a median follow-up time of 7.1 years (IQR 3.8). Among men with screen-detected AAA, 0.6% died of AAA-related causes (0.9 AAA-related deaths per 1000 person-years). The rupture rate was 0.3% among men with screen-detected AAA or subaneurysmal aortic dilatation, giving an incidence of 0.5 ruptures per 1000 person-years. The overall repair rate in the AAA group was 20.6% (36.1 repairs per 1000 person-years) and 0.6% (0.9 repairs per 1000 person-years) in the subaneurysm group. In a population screened for AAA, the incidence of rupture and the AAA-related mortality was very low. Almost one-fifth of the participants with screen-detected AAA underwent elective repair, representing a group that might have presented with rupture if untreated. These results indicate that screening is valuable in preventing AAA rupture and AAA-related mortality.

Psychosocial consequences after screening of abdominal aortic aneurysm among 65 year old men

BackgroundIn order to reduce the incidence of abdominal aortic aneurysm rupture and mortality, the Swedish Medical Council has introduced a national abdominal aortic aneurysm (AAA) screening program that offers ultrasound examination of 65-year-old men. Screening programmes of AAA may confer both benefits and harms. The study aim was to investigate the psychosocial consequences of AAA screening among men with screening-detected AAA as compared to men identified as AAA-negative at screening, using an AAA-specific questionnaire. MethodsThis cross-sectional study investigated the psychosocial consequences of AAA screening measured with a condition-specific questionnaire. This study focused on the Experience of the Diagnosis and the Screening Procedure in terms of Anxiety, Sense of Dejection and Existential Values. One hundred and fifty-eight men with AAA (63%) and 275 with normal aorta size (55%) completed the diagnosis-specific questionnaire. ResultsNinety-six percent of men with screening detected AAA did not regret the screening examination, the corresponding figure for controls being 99.6%. Seventy percent of AAA patients were surprised that something was wrong in their body. Some (85%) of men with AAA were current or previous smokers, about half of them (45%) felt guilty about it and 78% of the current smokers in the AAA group had considered stopping smoking. Both groups considered changing lifestyle, although at a higher rate (32%) among AAA cases than controls (20%), with differences both in intention to change their ways to exercise (p = 0.019) and food intake (p = 0.001).Intergroup differences were identified for the majority of items as captured by the questionnaire where men identified with AAA reported more negative psycho-social consequences for all evaluated items except for the items: Regret of the screening examination (p = 0.069) and feeling terrified (p = 0.10). Fifty-one percent of AAA cases stated that they feared rupture, and 12% were anxious about rupture during sexual activity whereas 57% were worried about rupture during intense physical activity. ConclusionMen who were diagnosed with AAA reported more psychosocial consequences compared to controls; still only a minority of AAA cases reported psychosocial consequences in greater occurrence. To some degree, men with AAA also feared rupture during various types of activities. There appears to be a need for improved patient information and easy access to caregivers for men with screening-detected AAA, which might help to reduce psychosocial consequences associated with the diagnosis.

Abdominal aortic aneurysm volume and relative intraluminal thrombus volume might be auxiliary predictors of rupture-an observational cross-sectional study.

The study aimed to identify differences and compare anatomical and biomechanical features between elective and ruptured abdominal aortic aneurysms (AAAs). Data (clinical, anatomical, and biomechanical) of 98 patients with AAA, 75 (76.53%) asymptomatic (Group aAAA) and 23 (23.46%) ruptured AAA (Group rAAA), were prospectively collected and analyzed. Anatomical, morphological, and biomechanical imaging markers like peak wall stress (PWS) and rupture risk equivalent diameter (RRED), comorbid conditions, and demographics were compared between the groups. Biomechanical features were assessed by analysis of Digital Imaging and Communication in Medicine images by A4clinics (Vascops), and anatomical features were assessed by 3Surgery (Trimensio). Binary and multiple logistic regression analysis were used and adjusted for confounders. Accuracy was assessed using receiving operative characteristic (ROC) curve analysis. In a multivariable model, including gender and age as confounder variables, maximal aneurysm diameter [MAD, odds ratio (OR) = 1.063], relative intraluminal thrombus (rILT, OR = 1.039), and total aneurysm volume (TAV, OR = 1.006) continued to be significant predictors of AAA rupture with PWS (OR = 1.010) and RRED (OR = 1.031). Area under the ROC curve values and correct classification (cc) for the same parameters and the model that combines MAD, TAV, and rILT were measured: MAD (0.790, cc = 75%), PWS (0.713, cc = 73%), RRED (0.717, cc = 55%), TAV (0.756, cc = 79%), rILT (0.656, cc = 60%), and MAD + TAV + rILT (0.797, cc = 82%). Based on our results, in addition to MAD, other important predictors of rupture that might be used during aneurysm surveillance are TAV and rILT. Biomechanical parameters (PWS, RRED) as valuable predictors should be assessed in prospective clinical trials. Similar studies on AAA smaller than 55 mm in diameter, even difficult to organize, would be of even greater clinical value.

Patients with abdominal aortic aneurysms have reduced levels of microRNA 122-5p in circulating exosomes.

There are currently no specific biomarkers to identify patients with abdominal aortic aneurysms (AAAs). Circulating exosomes contain microRNAs (miRNA) that are potential biomarkers for the presence of disease. This study aimed to characterize the exosomal miRNA expression profile of patients with AAAs in order to identify novel biomarkers of disease. Patients undergoing duplex ultrasound (US) or computed tomography (CT) for screening or surveillance of an AAA were screened to participate in the study. Cases with AAA were defined as having a max aortic diameter >3 cm. Circulating plasma exosomes were isolated using Cushioned-Density Gradient Ultracentrifugation and total RNA was extracted. Next Generation Sequencing was performed on the Illumina HiSeq4000 SE50. Differential miRNA expression analysis was performed using DESeq2 software with a Benjamini-Hochberg correction. MicroRNA expression profiles were validated by Quantitative Real-Time PCR. A total of 109 patients were screened to participate in the study. Eleven patients with AAA and 15 non-aneurysmal controls met study criteria and were enrolled. Ultrasound measured aortic diameter was significantly larger in the AAA group (mean maximum diameter 4.3 vs 2.0 cm, P = 6.45x10-6). More AAA patients had coronary artery disease (5/11 vs 1/15, P = 0.05) as compared to controls, but the groups did not differ significantly in the rates of peripheral arterial disease and chronic obstructive pulmonary disease. A total of 40 miRNAs were differentially expressed (P<0.05). Of these, 18 miRNAs were downregulated and 22 were upregulated in the AAA group compared to controls. After false discovery rate (FDR) adjustment, only miR-122-5p was expressed at significantly different levels in the AAA group compared to controls (fold change = 5.03 controls vs AAA; raw P = 1.8x10-5; FDR P = 0.02). Plasma exosomes from AAA patients have significantly reduced levels of miRNA-122-5p compared to controls. This is a novel exosome-associated miRNA that warrants further investigation to determine its use as a diagnostic biomarker and potential implications in AAA pathogenesis.

Single-cell transcriptome in silico analysis reveals conserved regulatory programs in macrophages/monocytes of abdominal aortic aneurysm from multiple mouse models and human.

Abdominal aortic aneurysm (AAA) is a life-threatening disease and there is currently a lack of effective treatment to prevent it rupturing. ScRNA-seq studies of AAA are still lacking. In the study, we analyzed the published AAA scRNA-seq datasets from the mouse elastase-induced model, CaCl2 treatment model, Ang II-induced model and human by using bioinformatic approaches and in silico analysis. A total of 26 cell clusters were obtained and 11 cell types were identified from multiple mouse AAA models. Also, the proportion of Mφ/Mo increased in the AAA group and Mφ/Mo was divided into seven subtypes. There were significant differences in transcriptional regulation patterns of Mφ/Mo in different AAA models. The enrichment pathways of upregulated or downregulated genes from Mφ/Mo in the three mouse datasets were different. The actived regulons of Mφ/Mo had strong specificity and the repressed regulons showed high consistency. The co-upregulated genes as well as actived regulons and co-downregulated genes as well as repressed regulons were closely correlated and formed regulatory networks. Mφ/Mo from human AAA dataset was divided into five subtypes. The proportion of three macrophage subpopulations increased but the proportion of two monocyte subpopulations decreased. In the AAA group, the upregulated or downregulated genes of Mφ/Mo were enriched in different pathways. After further analyzing the genes in Mφ/Mo of both mouse and human scRNA-seq datasets, two genes were upregulated in the four datasets, IL-1B and THBS1. In conclusion, in silico analysis of scRNA-seq revealed that Mφ/Mo and their regulatory related genes as well as interaction networks played an important role in the pathogenesis of AAA.

Association between Anthropometric Measurements and Vascular Disease: A Cross Sectional Study

The aim of this article is to assess the most studied anthropometric measurements in a population of patients with vascular disease (VD) such as chronic venous disease (CVD), carotid stenosis (CS), abdominal aortic aneurysm (AAA), and peripheral artery disease (PAD). This is a cross sectional study that recruited consecutive patients with VD (CVD, CS, AAA, PAD) referred to Vascular Surgery Units of two hospitals in the period July 2019–March 2022. Several anthropometric measurements such as height, weight, body mass index (BMI), waist circumference, waist-to-BMI, waist-to-hip ratio (WHR), A Body Shape Index (ABSI), waist-to-stature ratio (WSR) were recorded. In a one-way ANOVA test, no statistical significance for all anthropometric variables were found, but the post hoc analysis performed with Tuckey test, show significant difference for height (p-value: 0.017) and WHR (p-value: 0.005) when compared AAA and CS groups with CVD, respectively. Height seems positively associated with AAA, and negatively associated with CVD. WHR seems positively associated with CS and negatively associated with CVD. Further studies are needed to clarify the role of anthropometric measures as independent predictors for vascular disease onset, progression, and response to treatments.

Survey of Food Intake in Patients with Abdominal Aortic Aneurysm.

Abdominal aortic aneurysm (AAA) is a vascular disease that involves asymptomatic progressive expansion of the abdominal aorta. Aneurysm rupture is associated with a high mortality rate. Dietary conditions may be associated with the development and rupture of AAA. However, the relationship between nutrition and AAA is not completely understood. In this study, a nutrition survey was conducted using a brief self-administered diet history questionnaire (BDHQ) to evaluate the relationship between AAA and dietary habits. One-hundred and twenty-six Japanese people participated in the nutrition survey. Food intake status was analyzed in four groups: the analyzed group-1 (all men), analyzed group-2 (men with smoking history), analyzed group-3 (all women) and analyzed group-4 (women without smoking history). In group-2 and group-3, the intake of citrus fruits was significantly lower in the AAA group than in the non-AAA group. In group-2, the intake of soybean and soybean products was significantly lower in the AAA group than in the non-AAA group. In analyzed group-3, the intake of other vegetables (vegetables except for green and yellow vegetables and soybeans) and seafood was significantly lower in the AAA group than in the non-AAA group. This study suggests that AAA onset may be associated with low intake of fruits, soybeans, vegetables, and seafood.

Risk of various cancers in adults with abdominal aortic aneurysms.

The cause of death for patients with an abdominal aortic aneurysm (AAA) can be related to the AAA itself. However, cancer-related mortality could also be a contributing factor. In the present study, we examined the hypothesis that an association exists between AAAs and certain cancers. Information from 2009 to 2015 was extracted from the Korean National Health Insurance Service database. We included 14,920 participants with a new diagnosis of an AAA. Propensity score matching by age and sex with disease-free patients was used to select the control group of 44,760 participants. The primary end point of the present study was a new diagnosis of various cancers. The hazard ratio (HR) for cancer incidence was higher in the AAA group than in the control group for hepatoma, pancreatic cancer, and lung cancer (HR, 1.376, 1.429, and 1.394, respectively). In the case of leukemia, the HR for cancer occurrence was not significantly higher in the AAA group than in the control group. However, when stratified by surgery, the HR was significantly higher for the surgical group (HR, 3.355), especially for endovascular aneurysm repair (HR, 3.864). We found that AAAs are associated with an increased risk of cancer, in particular, hepatoma, pancreatic cancer, and lung cancer, even after adjusting for several comorbidities. Thus, continued follow-up is necessary for patients with an AAA to permit the early detection of the signs and symptoms of cancer.

Impact of Bifidobacterium adolescentis in patients with abdominal aortic aneurysm: a cross-sectional study.

The relationships between various diseases and the human gut microbiota (GM) have been revealed. However, the relationships between the human abdominal aortic aneurysm (AAA) and GM remains unknown. The aim of this cross-sectional study was to clarify the association between the human AAA and GM. Stool samples from 30 consecutive patients with AAA before aneurysm repair and those of 30 controls without vascular diseases were analyzed by 16S rRNA gene (V3-4) sequencing using an Illumina MiSeq system and QIIME 2. There was no significant difference in age (75 vs. 75 years) or gender (80% vs. 87% males) between the groups. No significant difference in GM composition was observed in principal coordinate analysis between the two groups, whereas the AAA group showed a significantly lower abundance of Bifidobacterium adolescentis (p<0.01) at the species level than the controls. This study demonstrated that the abundance of B. adolescentis decreased in patients with AAA. This is the first study to show the characteristics of the GM in patients with AAA. Studies are needed to reveal if causal relationships exists between the human AAA and GM.

Revealing the Intercellular Communication Changes of Human Abdominal Aortic Aneurysms at Single-cell Resolution

Abstract Background: Abdominal aortic aneurysm (AAA) is a chronic vascular inflammation progression with a high mortality. However, intercellular communication has not been sufficiently explored in human AAA tissue. Aims: Here, we investigated available single-cell RNA sequencing data generated from human AAA. Results: These cells were divided into 27 clusters and 6 main cell types, such as T-cells, B-cells, myeloid cells, neutrophils, endothelial cells, and fibroblasts. Immune cells were present in AAA tissues more than control. In addition, we established an intercellular communication network and observed a more pronounced enrichment of TGFB1, CCL, VEGF, IL6, and complement pathways in the AAA group compared to the control group. Conclusion: Together, our analyses provide beneficial insight into cell–cell communication and expand channels for the effective immunotherapy development of AAA in the future.

Kinetics of d-lactate and ischemia-modified albumin after abdominal aortic surgery and their ability to predict intestinal ischemia

ObjectivesAcute intestinal ischemia is a severe complication of abdominal aortic surgery that is difficult to diagnose early and therefore to treat adequately and timely. In this study the perioperative kinetics of d-lactate and ischemia-modified albumin (IMA) are described and the predictive value of these markers for the early diagnosis of acute intestinal ischemia is assessed. Design & methodsThis non-randomised, single-centre cohort study enrolled 50 patients with abdominal aortic aneurysm (AAA) and 30 patients with aortoiliac occlusive disease (AOID). Serum d-lactate and IMA were assessed pre-, intra-, and postoperatively at eight defined time points. ResultsThe highest serum d-lactate was at 6 h after complete declamping of the vascular graft. The highest predictive power of d-lactate was at 3 h after complete declamping (AUC 0.857). IMA was found to be higher in the AAA group in ischemic patients 10 min after complete declamping than in the AOID group. The highest predictive values of IMA were at 1 h after aortic cross-clamping (AUC 0.758) and 3 and 6 h after complete declamping (0.745 and 0.721, respectively). Moreover, the multivariate model with both markers at 3 h after complete declamping improved the detection of intestinal ischemia (AUC 0.894). ConclusionsSerum levels of IMA and d-lactate seem to be influential predictive markers for postoperative intestinal ischemia, especially after 3 h from complete declamping of vascular reconstruction.

Abstract 14040: Mechanical Aortic Strain Promotes Expression of Proteolytic Matrix Markers in Abdominal Aortic Aneurysm

Introduction: Serum biomarkers for abdominal aortic aneurysms (AAA) have been identified, but the prognostic relevance has remained unclear. Mechanical activation of aortic VSMCs can elicit production of interleukin-6 (IL-6), a cytokine consistently elevated in AAA. Expecting that stressed native aortic cells may drive degenerative remodeling, we hypothesize that biomarkers focused on matrix proteolysis may be elaborated directly from the aortic wall and assessed as an indicator of aortic strain. Methods: AAA was induced in C57Bl/6 mice with peri-adventitial CaCl 2 (n=5). Terminal procedure at 21 days quantified aortic diameter (AoD) by digital microscopy, obtained blood sampling, and collected aortic tissue. Aortic ultrasound (Vevo3100 with VevoVasc Software) was conducted on Days 0 and 21 to assess AoD and aortic strain parameters. Tissue and serum were analyzed to quantify IL-6 and the proteolytic matrix markers: matrix metalloproteinase-9 (MMP-9), Cathepsin S (CtsS), Cystatin C (CysC), and osteoprotegerin (OPG). Aortic VSMCs underwent mechanical stimulation with 12% Stretch and subsequent QPCR for expression of proteolytic matrix markers (n=4). Groups were analyzed by T-test and ANOVA. Results: At 21 days, all mice in AAA group developed true aneurysms by digital microscopy (&gt;50% dilation compared to internal baseline), and this correlated to measurements from transabdominal ultrasound. Aortic strain assessment indicated increased stiffness parameters in AAA (elevated Pulse Wave Velocity, decreased Distensibility, and decreased Global Radial Strain). The AAA group also had significantly elevated levels of IL-6, MMP-9, and OPG (p&lt;0.05 versus Control for each), with a trend toward increased CtsS and CysC. Alternatively, Stretch VSMCs demonstrated upregulated expression of IL-6, CysC, and OPG (p&lt;0.05 vs Static), while the proteases MMP-9 and CtsS remained unchanged. Conclusion: Mechanical activation of aortic VSMCs can stimulate expression of biomarker proteins associated with AAA, but protease production may rely on the inflammatory infiltrate to promote degenerative matrix remodeling. Further investigation into the source of common AAA biomarkers will provide insight for effective integration into patient care.

Abstract 11064: Role of Renin-Angiotensin System Axis in Human Abdominal Aortic Aneurysm

Introduction: Renin-Angiotensin System (RAS) regulates the cardiovascular system and has been implicated in the development of abdominal aortic aneurysm (AAA). RAS modulates function via balancing the ACE/Chymase/AngII-AT1 receptor and ACE-2/Ang(1-7)-Mas receptor axis. Preferential activation of the ACE/Chymase/AngII-AT1 receptor pathway of the RAS contributes to dysregulation of cardiovascular system and disease while the Ang(1-7)-MasR axis contributes to anti-inflammatory pathways. Therefore, identifying the RAS axis mechanism involved in growth, progression, or the risk of rupture in AAA humans could bring a novel treatment perspective. Hypothesis: We hypothesize that in the AAA, the local RAS is altered such as it favours the ACE/AngII/AT1R axis while decreasing the ACE-2/Ang(1-7)/MasR pathway, with consequent AAA development. Objective: We sought to investigate the expression of RAS components in the AAA human aorta. Methods: Aorta tissue from AAA patients (n=21) was collected during the AAA conventional repair surgery, and aorta control aortas were obtained from organ donors (Control, n=11). Protein expression of renin, chymase, ACE, ACE-2 AT1, AT2, and MAS receptors was analyzed by Western Blotting. Results: Our AAA cohort consisted mostly males (76.6% AAA vs. 63.6% Control, p=0.68), smokers or ex-smokers (90.4% AAA vs. 36.3% Control, p=0.002) and most of them had hypertension(71.4% AAA vs. 36.3% Control, p=0.07). Analysis of protein expression in the AAA group showed that ACE and AT1 receptors were upregulated compared with Control (p=0.05; p=0.02, respectively,), while chymase expression was decreased in AAA compared to the control (p=0.03). Additionally, the AAA group showed downregulation in ACE-2 and AT2 compared with Control (respectively, p=0.01, p=0.03). There was no significant difference in the expression of renin and MAS receptors between groups (p=0.52, p=0.41, respectively,). Conclusions: Our data show that the ACE/AT1R axis was upregulated while ACE-2 and AT2 receptors were downregulated in the AAA aorta. Our results implicate local RAS in AAA development and warrant further studies.