Abdominal Aneurysm Research Articles

Heart rate variability as a dynamic marker of surgeons' stress during vascular surgery.

A surgeon experiences elevated stress levels when operating. Acute stress is linked to cognitive overload, worsening surgical performance. Chronic stress poses a significant risk to a surgeon's health. Identifying intraoperative stress may allow for preventative strategies that reduce surgeons' stress and subsequently improve patient outcomes. The aim of this study was to assess the feasibility of using heart rate variability as a marker of stress during vascular surgery. A total of 11 senior surgeons were evaluated performing three different vascular surgery procedures. Heart rate variability metrics (low-frequency to high-frequency ratio and standard deviation of the normal-normal interval) were determined from single-lead ECG traces at predetermined procedural performance points. State-Trait Anxiety Inventory-6, a validated stress tool, was used to assess surgeon-reported stress. Subjective reports of procedural difficulty were also collected. One-way ANOVA compared heart rate variability at key performance points with baseline. Pearson's coefficient assessed correlation between heart rate variability and subjective stress. Data were collected for six carotid endarterectomies, six open abdominal aortic aneurysm repairs, and five lower limb bypasses. Heart rate variability metrics indicating markedly greater stress were observed at key performance points across all procedures. Peaks in stress were consistent across different surgeons performing the same procedure. A significant correlation was observed between heart rate variability metrics and subjective State-Trait Anxiety Inventory-6 stress reports (r = 0.768, P =<0.001). The most difficult procedural steps reported corresponded with heart rate variability metrics displaying the greatest stress. Heart rate variability may be a viable approach to assess intraoperative stress and cognitive load during vascular surgery and could be used to evaluate whether a theatre intervention (for example timeout) could reduce stress in areas of surgical difficulty.

O64 ENHANCED EXPRESSION AND MEDIAL LAYER LOCALIZATION OF ELASTASE-2, AN ANGIOTENSIN ENZYME: IMPACT ON ABDOMINAL AORTIC ANEURYSM HALLMARKS IN MICE

Abdominal aortic aneurysm (AAA) is a pathological dilation of the abdominal aorta that can lead to death, with no pharmacological treatment available other than repair surgery. Continuous angiotensinII (AngII) infusion induces AAA in mice. Elastase-2 (ELA-2), a chymotrypsin-serine protease and an elastase family member, acts as an AngII enzyme in arteries and contributes to resistance arteries and vascular remodeling in animal models. Therefore, ELA-2 is a potential factor in AAA formation and/or development. We sought to investigate the expression and localization of ELA-2 in AAA-induced mice. Methods: Male wild-type (C57bl/6,WT) and ELA-2knockout (CELA-2aTm1Bdr; ELA-2KO) mice treated with saline (WT+Sal n=10, ELA-2KO+Sal, n=9) or AngII (1.500ng/kg/min, WT+AngII n=8, ELA-2KO+AngII n=8) for twenty-eight days by subcutaneously mini-pumps infusion. Vascular ultrasonography (US, Vevo2100) analyzed, before and after treatment, aortic expansion index, aortic systolic and diastolic diameter parameters. The immunofluorescence for ELA-2, aorta layer, and histologic staining to collagen, elastin, and fibrosis was analyzed. A correlation between ELA-2 and US was done. Results: WT+AngII mice developed AAA, and ELA-2KO mice did not have AAA by infusion of Ang II. Aorta ELA-2 expression up-regulated in WT-AngII vs. WT+Sal (p=0.0001). Aortic systolic diameter increased in the WT+AngII vs WT+Sal (0.8vs.1.5 mm, p&lt;0.0001). Aortic diastolic diameter increases in the WT+AngII vs WT+Sal (1.2 vs.0.6 mm, p&lt;0.0001). The aortic expansion index decreases in WT+Ang II vs WT+Sal (11.4 vs.17.1%, p=0.0008). WT+AngII aorta has higher collagen deposition and fibrosis and lower elastin than WT+Saline (p=0.001). ELA-2KO+AngII vs. ELA-2KO+SAL showed no difference in elastin, collagen, and fibrosis. The analyzed parameters characteristic of AAA showed a positive correlation with ELA-2 in aorta middle layer in WT+AngII, where AAA develops. Conclusion: ELA-2 expression is up-regulated in AAA mice’s aorta and may contribute to developing aneurysms. ELA-2KO might be less susceptible to developing AAA induced by AngII infusion. Therefore, ELA-2 plays a significant role in AAA pathophysiology and could be a potential target for therapeutic treatment to prevent AAA development.

Metformin Improves the Function of Abdominal Aortic Aneurysm Patient-Derived Aortic Smooth Muscle Cells

Type 2 diabetes mellitus (T2DM) is a cardiovascular risk factor. Paradoxically, a decreased risk of abdominal aortic aneurysm (AAA) presence and growth rate is described among patients with T2DM, associated with metformin use. This study aimed to investigate the effect of metformin on AAA patient derived aortic smooth muscle cell (SMC) function. Aortic biopsies were obtained from patients with AAA (n = 21) and controls (n = 17) during surgery. The SMCs of non-pathological aortic controls, non-diabetic patients with AAA, and diabetic patients with AAA were cultured from explants and treated with or without metformin. The SMC contractility was measured upon ionomycin stimulation, as well as metabolic activity, proliferation, and migration. Then, mRNA and protein expression of markers for contraction, metabolic activity, proliferation, and inflammation were measured. The mRNA expression of KLF4 and GYS1, genes involved in metabolic activity, differed between the SMCs from non-diabetic and diabetic patients with AAA before metformin stimulation (p < .041). However, the effect of metformin on the various SMC functions was similar between non-diabetic and diabetic patients with AAA. Upon stimulation, metformin increased the contractility of AAA patient SMCs (p = .001). The mRNA expression of smoothelin, a marker for the contractile phenotype, increased in the SMCs of patients with AAA after treatment with metformin (p = .006). An increase in metabolic activity (p < .001) and a decrease in proliferation (p < .001) and migration were found in the SMCs of controls and patients with AAA with metformin. Increased mRNA expression of PPARγ, a nuclear receptor involved in mitochondrial biogenesis (p < .009), and a decrease in gene expression of Ki-67, a marker for proliferation (p < .005), were observed. Gene expression of inflammation markers MCP-1 and IL-6, and protein expression of NF-κB p65 decreased after treatment with metformin in patients with AAA. This study found that metformin increases contractility and metabolic activity, and reduces proliferation, migration, and inflammation in aortic SMCs in vitro.

Risk factors for abdominal aortic aneurysm in patients with diabetes

ObjectiveAlthough diabetes has been shown to be negatively associated with development of abdominal aortic aneurysm (AAA), patients with diabetes may still develop aneurysms. In this study, we examined risk factors for the development of AAA in patients with diabetes. MethodsAdults >50 years of age with diabetes who underwent health screening between 2009 and 2012 were followed for incident AAA until December 31, 2019. Cox proportional hazard regression models were used to calculate multivariate hazard ratios (HRs) and 95% confidence intervals (CIs) for risk factors associated with AAA. ResultsAmong 1,913,066 participants (55.3% men), 6996 AAA cases were identified during a mean follow-up of 7.7 years. Increased AAA risk was observed for age ≥65 years (HR, 2.69; 95% CI, 2.55-2.83), men (HR, 1.81; 95% CI, 1.69-1.94), smoking (former smoker ≥20 pack-years [PY]; HR, 1.75; 95% CI, 1.61-1.89; current smoker <20 PY; HR, 1.76; 95% CI, 1.59-1.94; current smoker ≥20 PY; HR, 2.40; 95% CI, 2.23-2.59), abdominal obesity (HR, 1.30; 95% CI, 1.23-1.38), and comorbidities, including hypertension (HR, 1.63; 95% CI, 1.53-1.73), dyslipidemia (HR, 1.35; 95% CI, 1.29-1.42), chronic kidney disease (HR, 1.52; 95% CI, 1.44-1.61), and cardiovascular disease (HR, 1.71; 95% CI, 1.58-1.86). Heavy (HR, 0.67; 95% CI, 0.61-0.74) and mild alcohol consumption (HR, 0.78; 95% CI, 0.74-0.83), overweight (HR, 0.87; 95% CI, 0.81-0.93) and obesity (HR, 0.81; 95% CI, 0.75-0.87), longer diabetes duration (≥5 years: HR, 0.74; 95% CI, 0.70-0.78), and using three or more oral hypoglycemic agents (OHA) (HR, 0.84; 95% CI, 0.79-0.90) were associated with decreased AAA risk, whereas insulin use was associated with a marginally increased risk (HR, 1.09; 95% CI, 1.00-1.18). Among the OHAs, metformin (HR, 0.95; 95% CI, 0.90-1.00), thiazolidinediones (HR, 0.87; 95% CI, 0.79-0.97), and sulfonylureas (HR, 0.88; 95% CI, 0.83-0.93) were associated with a decreased risk of AAA. ConclusionsAlthough diabetes is associated with decreased AAA risk, those with comorbid cardiometabolic diseases, abdominal obesity, and a smoking history should be aware of an increased AAA risk. Further studies are warranted to verify the potential use of OHAs for decreasing AAA risk.

Single-Cell RNA Sequencing Deconstructs the Distribution of Immune Cells Within Abdominal Aortic Aneurysms in Mice.

Inflammation is a key component in the development of abdominal aortic aneurysm (AAA), yet insights into the roles of immune cells and their interactions in this process are limited. Using single-cell RNA transcriptomic analysis, we deconstructed the CD45+ cell population in elastase-induced murine AAA at the single-cell level. We isolated each group of immune cells from murine AAA tissue at different time points and divided them into several subtypes, listed the remarkable differentially expressed genes, explored the developmental trajectories of immune cells, and demonstrated the interactions among them. Our findings reveal significant differences in several immune cell subsets, including macrophages, dendritic cells, and T cells, within the AAA microenvironment compared with the normal aorta. Especially, conventional dendritic cell type 1 exclusively existed in the AAA tissue rather than the normal aortas. Via CellChat analysis, we identified several intercellular communication pathways like visfatin, which targets monocyte differentiation and neutrophil extracellular trap-mediated interaction between neutrophils and dendritic cells, which might contribute to AAA development. Some of these pathways were validated in human AAA. Despite the absence of external pathogenic stimuli, AAA tissues develop a complex inflammatory microenvironment involving numerous immune cells. In-depth studies of the inflammatory network shall provide new strategies for patients with AAA.

Aortic aneurysm: pathophysiology and therapeutic options.

Aortic aneurysm (AA) is an aortic disease with a high mortality rate, and other than surgery no effective preventive or therapeutic treatment have been developed. The renin-angiotensin system (RAS) is an important endocrine system that regulates vascular health. The ACE2/Ang-(1-7)/MasR axis can antagonize the adverse effects of the activation of the ACE/Ang II/AT1R axis on vascular dysfunction, atherosclerosis, and the development of aneurysms, thus providing an important therapeutic target for the prevention and treatment of AA. However, products targeting the Ang-(1-7)/MasR pathway still lack clinical validation. This review will outline the epidemiology of AA, including thoracic, abdominal, and thoracoabdominal AA, as well as current diagnostic and treatment strategies. Due to the highest incidence and most extensive research on abdominal AA (AAA), we will focus on AAA to explain the role of the RAS in its development, the protective function of Ang-(1-7)/MasR, and the mechanisms involved. We will also describe the roles of agonists and antagonists, suggest improvements in engineering and drug delivery, and provide evidence for Ang-(1-7)/MasR's clinical potential, discussing risks and solutions for clinical use. This study will enhance our understanding of AA and offer new possibilities and promising targets for therapeutic intervention.

Chronic intermittent hypoxia facilitates the development of angiotensin II-induced abdominal aortic aneurysm in male mice.

Obstructive sleep apnea (OSA), characterized by episodes of intermittent hypoxia (IH), is highly prevalent in patients with abdominal aortic aneurysm (AAA). However, whether IH serves as an independent risk factor for AAA development remains to be investigated. Here, we determined the effects of chronic (6 mo) IH on angiotensin (Ang II)-induced AAA development in C57BL/6J male mice and investigated the underlying mechanisms of IH in cultured vascular smooth muscle cells (SMCs). IH increased the susceptibility of mice to develop AAA in response to Ang II infusion by facilitating the augmentation of the abdominal aorta's diameter as assessed by transabdominal ultrasound imaging. Importantly, IH with Ang II augmented aortic elastin degradation and the expression of matrix metalloproteinases (MMPs), mainly MMP8, MMP12, and a disintegrin and metalloproteinase-17 (ADAM17) as measured by histology and immunohistochemistry. Mechanistically, IH increased the activities of MMP2, MMP8, MMP9, MMP12, and ADAM17, while reducing the expression of the MMP regulator reversion-inducing cysteine-rich protein with Kazal motifs (RECK) in cultured SMCs. Aortic samples from human AAA were associated with decreased RECK and increased expression of ADAM17 and MMPs. These data suggest that IH facilitates AAA development when additional stressors are superimposed and that this occurs in association with an increased presence of aortic MMPs and ADAM17, potentially due to IH-induced modulation of RECK expression. These findings support a plausible synergistic link between OSA and AAA and provide a better understanding of the molecular mechanisms underlying the pathogenesis of AAA.NEW & NOTEWORTHY IH facilitates Ang II-induced abdominal aortic diameter expansion and AAA development in C57BL/6J male mice. IH upregulates the expression of specific MMPs such as MMP8, MMP12, and ADAM17. IH directly suppresses RECK expression and increases MMPs activity in SMCs. Human AAA tissues exhibit a downregulation of RECK and an upregulation of ADAM17 and MMPs.

Early results from the pivotal trial substudy of the GORE EXCLUDER conformable endoprosthesis in angulated necks

ObjectiveTo report the investigational device exemption study 1-year clinical outcomes of the high neck angulation (HNA) substudy of the GORE EXCLUDER Conformable AAA Endoprosthesis (EXCC) for treatment of infrarenal abdominal aortic aneurysms (AAAs). MethodsThis study is a prospective, multicenter clinical trial conducted in the United States and included core laboratory assessment of imaging and independent event adjudication. Anatomical criteria for enrollment in the HNA substudy included infrarenal aortic neck angulation >60° and ≤90° with aortic neck length ≥10 mm. Primary safety end points included estimated blood loss of >1000 mL, death, stroke, myocardial infarction, bowel ischemia, paraplegia, respiratory failure, renal failure, and thromboembolic events. Primary effectiveness end points included technical success, absence from type I and III endoleaks, migration (≥10 mm), sac enlargement (≥5 mm), sac rupture, and conversion to open repair. ResultsBetween January 2018 and February 2022, 95 patients were enrolled in the HNA substudy across 35 sites. Of the 95 patients, 71 (74.7%) were male and the cohort average age was 74.4 years. The mean infrarenal proximal aortic neck angle was 71.6° and the mean AAA size was 62.9 mm. Overall technical success was achieved in 93 patients (97.9%). Freedom from a primary safety end point through 30 days was 96.7%; 3 (3.3%) patients had an estimated blood loss of >1000 mL. Freedom from the primary effectiveness at 12 months was achieved in 94.8%. Four patients (4.3%) had a type IA endoleak; intervention after the procedure was not required and no subsequent interventions or sac enlargement were noted in these patients. At 12 months, 29 patients (39.7%) experienced a type II endoleak and 1 (1.3%) patient experienced AAA sac expansion of ≥5 mm. Through 12 months, 1 patient (1.3%) had a conversion to open surgical repair. There were no aneurysm-related deaths, ruptures, or migration through 12 months. ConclusionsThe investigational device exemption study demonstrates safety and effectiveness of the GORE EXCLUDER Conformable AAA Endoprosthesis device in AAA with highly angulated necks (>60° and ≤90°) are preserved at the 12-month follow-up.

Quercetin Promotes Abdominal Aortic Aneurysm Regression Through the RAGE/PI3K/AKT/mTOR Axis

Objective: Abdominal aortic aneurysms (AAA) are a common critical cardiovascular disease with high morbidity and mortality rates. Quercetin, a flavonoid and a traditional Chinese medicinal ingredient commonly found in vegetables and fruits, has a favorable inhibitory effect on experimental aneurysms without side effects. This study aimed to model elastase AAA and investigate the mechanism of action of quercetin in alleviating AAA. Methods: Quercetin was administered at a dose of 60 mg/kg once daily starting on the day of AAA induction for 5 weeks. The therapeutic effect of quercetin on AAA was demonstrated using biochemical assays, observation of pathological tissue sections, Elastic Van Gieson staining, immunohistochemistry, molecular docking simulations, and Western blot protein validation. Results: Our study showed that quercetin treatment significantly alleviated abdominal aortic vessel wall dilatation, elastin degradation and adhesion to surrounding tissues caused by elastase. Additionally, quercetin significantly inhibited the mRNA and protein expression of the receptor for advanced glycation end products(RAGE)/ phosphatidylinositol 3-kinase (PI3K)/ phosphatidylinositol 3-kinase (AKT) / mammlian target of rapamycin (mTOR) pathway. Conclusion: Quercetin can alleviate abdominal aortic injury caused by elastase via RAGE/PI3K/AKT/mTOR and provide experience in clinical use.

Anatomical Suitability of Iliac Branch Devices for East Asian Patients with Abdominal Aortic Aneurysm

This study aimed to identify the iliac artery characteristics of East Asian patients with abdominal aortic aneurysms (AAAs) and to evaluate anatomical suitability rates with current iliac branch devices (IBDs). This was a single centre, retrospective, cross sectional study. Patients diagnosed with AAA between 2008 and 2023 were enrolled. The morphological parameters of the iliac arteries were measured, and their eligibility for four IBDs (Cook ZBIS, Gore IBE, E-Liac IBD, and G-Iliac IBD) was evaluated according to the manufacturer's latest instructions for use (IFU). Among 1 144 AAAs observed in the study, 45.5% (n= 521) presented with concurrent common iliac artery aneurysm (CIAA). In total, 304 patients (26.6%) and 371 iliac arteries necessitated internal iliac artery (IIA) reconstruction. The anatomical suitability rates for the Cook ZBIS, Gore IBE, E-Liac IBD, and G-Iliac IBD were 18.9%, 21.8%, 11.9%, and 22.6%, respectively. The E-Liac IBD exhibited a significantly lower anatomical suitability rate compared with the other three devices (p < .001). The primary IBD exclusion criteria were: a common iliac artery (CIA) length of < 50 mm for Cook ZBIS (n= 211, 56.9%); an IIA diameter of < 6.5 mm or > 13.5 mm for Gore IBE (n= 177, 47.7%); and a CIA bifurcation diameter of < 18 mm both for E-Liac IBD and G-Iliac IBD (n= 244, 65.8%). A total of 198 patients (53.4%) failed to meet the anatomical criteria for any device, while 112 (30.2%) qualified for just one device, 26 (7.0%) for two devices, 25 (6.7%) for three devices, and 10 (2.7%) for all four devices. A significant proportion of East Asian patients with AAA present with concurrent CIAA, necessitating substantial IIA reconstruction. IBD techniques show low anatomical suitability rates among the East Asian population, with 53.4% of patients failing to meet anatomical criteria for any IBD based on the manufacturer's IFU.

Aortic Uptake of 18F-NaF and 18F-FDG and Calcification Predict the Development of Abdominal Aortic Aneurysms and Is Attenuated by Drug Therapy.

Abdominal aortic aneurysms expand over time and increase the risk of fatal ruptures. To predict expansion, the isolated assessment of 18F-fluorodeoxyglucose (FDG) and sodium fluoride (NaF) uptake or calcification volume in aneurysms has been investigated with variability in results. We systematically evaluated whether 18F-FDG and 18F-NaF uptake was predictive of abdominal aortic aneurysm expansion. Seventy-four male Sprague-Dawley rat abdominal aortic aneurysm models were imaged using positron emission tomography-computed tomography with 18F-FDG and 18F-NaF at 1, 2, 4, 6, and 8 weeks after CaCl2 or saline stimulation. In the 1-week cohort (n=25), the correlation between 18F-FDG or 18F-NaF uptake and pathological markers was investigated. In the time course cohort (n=49), animals received either atorvastatin, losartan, aldactone, or risedronate to assess the effect of these drugs, and the relationship between aortic size and sequential 18F-FDG and 18F-NaF uptake or calcification volume was examined. In the 1-week cohort, the maximum standard unit value of 18F-FDG and 18F-NaF uptake correlated with CD68- (r=0.82; P=0.001) and von Kossa staining-positive areas (r=0.89; P<0.001), respectively. In the time course cohort, 18F-FDG and 18F-NaF uptake changed in a time-dependent manner and drugs attenuated this uptake. Specifically, 18F-FDG showed high uptake at weeks 1 and 2, whereas a high 18F-NaF uptake was noted throughout the study period. Atorvastatin and risedronate showed a decreased and increased aortic size, respectively. The final aortic area correlated well with 18F-FDG and 18F-NaF uptake and calcification volume, especially at 1 and 2 weeks (18F-NaF [1 week]: r=0.61, 18F-FDG [2 weeks]: r=0.51, calcification volume [1 week]: r=0.59; P<0.001). Multiple linear regression analysis showed that the combination of these factors predicted the final aortic size, with 18F-NaF uptake at 1 week being the strongest predictor. The uptake of 18F-NaF and 18F-FDG and the calcification volume at appropriate times correlated with the development of abdominal aortic aneurysms, with 18F-NaF uptake being the strongest predictor.

Three-Year Outcomes of a US Pivotal Trial Substudy for Conformable Endoprosthesis in >=10 mm Non-Angulated Neck Anatomy

To report the midterm clinical outcomes from the GORE® EXCLUDER® Conformable AAA Endoprosthesis system (EXCC) pivotal regulatory trial in the United States (U.S.). This is a prospective, multicenter, investigational device exemption clinical trial at 31 US. sites with Core Laboratory assessment of imaging and independent adjudication of safety. The study enrolled patients with abdominal aortic aneurysms (AAA) with a minimum proximal landing zone ≥10mm and proximal neck angulation of ≤60 degrees between December 2017 and February 2019 as part of a larger study to gain indications of the EXCC device. Endpoints included patient survival, freedom from secondary interventions, and stent-graft related outcomes. There were 80 patients enrolled (88.8% male, mean 73.5± 8.14 years-old). Mean maximum aortic diameter was 57.7±8.0mm (range, 42.5-82.7). There was 100% freedom from type I and III endoleak and aneurysm-related mortality at 36-months. Freedom from secondary intervention was 91.9± (0.83, 0.96, 95% C.I.) at 36-months. There were no device fractures, migrations (≥10mm), or aneurysm ruptures. At 36months, thirteen patients (26.5%) had type 2 endoleak, 32 patients (58.2%) had AAA sac regression, 17 (30.9%) had no change in diameter, and 6 (10.9%) had sac enlargement. Seven patients (8.8%) through 36months underwent reintervention. The 3-year outcomes have continued to show an adequate safety and efficacy profile of the EXCC device with no aneurysm related mortality or Type I/III endoleak. These results demonstrate durability for an EVAR device in US regulatory trials.

Aorto caval fistulas.

The purpose of this paper is to examine and assess the outcomes following open repair in 39 patients who experienced aorto-caval fistula (ACF) resulting from the spontaneous rupture of an abdominal aortic aneurysm (AAA). We reviewed the clinical records of all patients surgically treated with open repair for ACF at the Clinic for Vascular and Endovascular Surgery of the Serbian Clinical Center in Belgrade, Serbia, from January 2012 to February 2023. All of the patients in this series were consecutive and had aorto-caval fistula from AAA. No patients were excluded from the procedure due to the life-threatening nature of the state. A follow-up assessment was performed during the follow-up examination or by telephone interview with the patient or a family member. All patients were male, with mean age 67.4±8.3 years (range: 52-83 years). The 30-day mortality rate in our cohort was 35.9%, with three (7.7%) intraoperative deaths, and 11 deaths in the postoperative period (28.2%). A total of 25 patients out of 39 (64.1%) in the original cohort have survived the surgery and the postoperative period and were followed-up for a total of 67.1 person-years. The mean follow-up was 3.7±2.2 years (range 0.25-8.4 years). Two patients (8.0%) died during the follow-up, 16 patients (64.0%) survived, and seven (28.0%) were lost to follow-up. The long-term mortality rate in the cohort that survived the postoperative period was 3.0/100 person-years. ACF caused by spontaneous AAA rupture into the inferior caval vein or iliac veins is a relatively rare, life-threatening condition which requires prompt treatment. An exact preoperative diagnosis is essential for perioperative strategy. As the comparison of our results with the results from contemporary literature indicates, wherever possible endovascular repair should be considered since it results might be superior to open repair.

Impaired Pre-operative Ambulatory Capacity in Patients Undergoing Elective Endovascular Infrarenal Abdominal Aortic Aneurysm Repair is Associated with Increased Peri-operative Death

While ambulatory capacity is a readily assessable clinical indicator of functional status, its association with outcomes after endovascular aneurysm repair (EVAR) remains underexplored. This study aimed to investigate the association between pre-operative ambulatory status and outcomes following elective EVAR. A retrospective review of the multi-institutional Vascular Quality Initiative database was conducted for all patients who underwent elective infrarenal EVAR from 2009 - 2022. Patients were categorised into independent ambulation and impaired ambulation groups. A propensity score matched analysis was performed to produce two well matched cohorts in a 1:1 ratio without replacement. The primary outcome was 30 day death. Secondary outcomes included one year survival and in hospital major complications. Among 11 474 patients, 10 539 (91.8%) were independently ambulatory pre-operatively. Propensity score matching resulted in 885 matched pairs. The impaired ambulation group, although older (mean 77.6 vs. 76.3 years; p= .001), showed comparable baseline characteristics. Post-operatively, the impaired ambulation group had higher cumulative in hospital complications and death as well as 30 day death. Even after adjustment for age, impaired pre-operative ambulation was associated with increased in hospital and 30 day death (hazard ratio [HR] 2.27, 95% confidence interval [CI] 1.26 - 3.95; p= .006). Multivariable analysis demonstrated increasing cumulative risk of 30 day death in the setting of impaired pre-operative ambulatory status with age > 75 years requiring post-operative red blood cell transfusion > 2 units (HR 5.75, 95% CI 2.09 - 15.88; p < .001). Beyond 30 days, impaired pre-operative ambulation was not associated with increased one year death (HR 1.09, 95% CI 0.81 - 1.48; p= .570). Among patients who underwent elective infrarenal EVAR in this matched analysis, impaired pre-operative ambulatory capacity was associated with an increased risk of in hospital and 30 day death, further compounded by advanced age and post-operative transfusion. As such, a threshold higher than the traditional size criteria should be considered in shared decision making when determining options for the management of abdominal aortic aneurysm in this high risk cohort.

Abstract P227: Potential roles of vascular glucose transporter 1 in development of abdominal aortic aneurysm induced by angiotensin II

It has been reported that pharmacological inhibition of glycolysis attenuated abdominal aortic aneurysm (AAA) development in mice. Glucose transporters (GLUTs) incorporate glucose as a first step of glycolysis. GLUT1 over-expression in vascular smooth muscle cell (VSMC) appears to enhance atherosclerosis in a mouse model. In angiotensin II (AngII) plus BAPN model of mouse AAA, silencing of VSMC AngII type 1 rec receptors attenuated AAA development and rupture which was associated with less immune cell infiltration to the aortas. However, the role of VSMC GLUT1 in AAA remains elusive. Here we tested our hypothesis that VSMC GLUT1 deletion attenuates AAA development and rupture in mice. Rat aortic VSMC were obtained by the explant method. Media glucose consumption of cultured VSMCs was evaluated in the presence or absence of angiotensin II (AngII, 100 nM) stimulation and GLUT1 inhibitor BAY-876. GLUT1 floxed mice were crossed with tamoxifen-inducible SMMHC-Cre mice. At 6 weeks of age, mice were injected with 2 mg/kg tamoxifen for 5 days. Significant vascular GLUT1 silencing was confimed with immunofluorescent chemistry. As a control, tamoxifen-treated SMMHC-Cre male mice were utilized. At 8 weeks, AngII (1 μg/kg/min) was delivered for 4 weeks. In addition, mice were received 1 mg/mL BAPN during the first 2 weeks of AngII infusion. After 4weeks, all animals were euthanized and maximal external diameter of the abdominal aorta was measured. In cultured VSMC, glucose consumption increased by AngII was attenuated by pretreatment of 100 nM BAY-876. AngII plus BAPN significantly developed AAA in control mice. However, silencing of VSMC GLUT1 did not affect AAA development by AngII plus BAPN. The survival rate due to aortic rupture in VSMC GLUT1 silenced mice and control mice treated with BAPN and AngII were 60.0% and 57.1%, respectively. AngII induced hypertension in control mice and VSMC GLUT1 silenced mice. Although GLUT1 may be a primary VSMC GLUT to enhance glucose utilization in response to AngII stimulation, VSMC GLUT1 silencing did not alter AngII-dependent AAA development or rupture in a mouse model. Since pharmacological inhibition of GLUT attenuated AAA and associated macrophage infiltration, it is possible that GLUT1 or other GLUT expressed in macrophages may contribute to development of AAA. In conclusion, VSMC GLUT1 silencing did not alter AngII-dependent AAA development or rupture in a mouse model.

The overall outcome of aortoduodenal syndrome following endovascular vs open surgical interventions

ObjectiveAortoduodenal syndrome (ADS) is a direct compression of an abdominal aortic aneurysm against the superior mesenteric artery or the abdominal wall, causing mechanical bowel obstruction. The first such case was reported by Canadian Professor William Osler in 1905. This clinical condition is mainly treated surgically to relieve the obstruction either by open aneurysm repair or gastrointestinal bypasses and, recently, by endovascular interventions. This systematic review aimed to assess the outcomes of different interventions in terms of symptomatic improvement thoroughly, peri- and post-intervention aneurysmal size, and overall survival rates. MethodsGoogle Scholar, Pubmed, and the Cochrane Library databases were searched by two independent reviewers to collect case reports and short case series on aortodudenal syndrome written in English and published from January 2000 to July 2023. ResultsThis review was conducted on 28 articles published from 2001 to 2023, with a total of 30 cases included. The mean age of the patients was 73.76 ± 7.7 years; nausea and vomiting (97%), abdominal pain (73%), abdominal distention (63%) were the most common symptoms among presentation. Twenty-four patients (80%) had comorbidities; only 7 of them were known to have abdominal aortic aneurysm. The aneurysmal sac at presentation ranged from 3.8 to 11.0 cm, with a mean size of 7.2 ± 2.2 cm. Eleven patients (36.7%) underwent endovascular aortic repair (EVAR), and 17 patients (56.7%) had open aortic repair, and 2 patients (6.6%) had a gastrointestinal bypass, either gastrojejunostomy or Roux-en-Y gastric bypass. The size of the aneurysmal sac was reported for eight patients who underwent EVAR ranging from 3.8 to 11.0 cm with a mean size of 7.27 ± 2.65 cm before the intervention; after the intervention, the mean size was 6.48 ± 2.26 cm. Mortality was reported in two patients; one underwent gastrojejunostomy and the other underwent EVAR. ConclusionsAortoduodenal syndrome remains a rare condition; the choice of surgical intervention is affected by patient factors, surgeon experience, and resource availability. That necessitates tailoring a management plan for each patient.

A Novel Preoperative Risk Score to Identify Patients at High Risk for Nonhome Discharge after Elective Open Abdominal Aortic Aneurysm Repair

Non-home discharge (NHD) to a rehabilitation or skilled nursing facility after vascular surgery is poorly described despite its impact on patients. For home-dwelling patients undergoing elective surgery, the need for postoperative NHD can have meaningful implications on quality of life, long-term outcomes, and healthcare spending. Understanding post-surgical NHD risk is essential to preoperative counseling and shared decision making. This is particularly true for the treatment of abdominal aortic aneurysms as the postoperative course can vary between open and endovascular surgery. We aimed to identify independent predictors of NHD following elective open abdominal aortic aneurysm repair (OAR), and to create a clinically useful preoperative risk score. Elective OAR cases were queried from the SVS Vascular Quality Initiative from years 2013-2022. A risk score was created by splitting the data set into two-thirds for development and one-third for validation. A parsimonious stepwise hierarchical multivariable logistic regression controlling for hospital level variation was performed in the development dataset, and the beta-coefficients were used to assign points for a risk score. The score was then validated, and model performance assessed. Overall, 8,274 patients were included and 1,502 (18.2%) required NHD. At baseline, patients who required NHD were more likely to be ≥ 80 years old (23.6% vs. 6.5%), female (35.9% vs. 23.1%), not independently ambulatory (14.6% vs. 4.3%), anemic (24.4% vs. 13.9%), have COPD (41.6% vs. 30.7%), ASA class ≥ 4 (41.0% vs. 32.5%), and a supraceliac proximal clamp (9.8% vs. 5.7%; all P<0.05). Multivariable analysis in the development group identified the following independent predictors of NHD: age ≥ 80 years, not independently ambulatory, proximal clamp location, hypogastric artery occlusion, anemia (Hb <12 g/dL), chronic obstructive pulmonary disease, female sex, hypertension, and American Society of Anesthesiologists class ≥ 4. These were then used to create a 14-point risk score. Patients were stratified into three groups based upon their risk score: low risk (0-4 points; n=4,966) with an NHD rate of 9.9%, moderate risk (5-6 points; n=2,442) with an NHD rate of 25.5%, and high risk (≥ 7 points; n=886) with an NHD rate of 44.6%. The risk score had good predictive ability with c-statistic=0.73 for model development and c-statistic=0.72 in the validation dataset. This novel risk score can predict NHD following elective OAR using characteristics that can be identified preoperatively. Utilization of this score may allow for improved risk assessment, preoperative counseling, and shared decision making.

Fenestrated and Branched Endovascular Aortic Aneurysm Repair for Treating Juxtarenal Aneurysms: An Update.

Fenestrated and branched endovascular aortic aneurysm repair (f-EVAR, b-EVAR, respectively) are technically challenging procedures that have evolved over the last decade for complex aortic aneurysms. They are alternatives to surgical repair for suprarenal and juxtarenal aortic aneurysms. A Pubmed database was reviewed by searching keywords related to f-EVAR, b-EVAR, and juxta renal abdominal aortic aneurysm (AAA) from the last five years to see current indications, contemporary techniques, and results of these techniques for juxtarenal aneurysms. Over the years, f-EVAR and b-EVAR have improved, with high technical success (>95%) and mortality rates of 1-5% for pararenal and 5-10% for thoracoabdominal aortic aneurysms. Key Words: Fenestrated-branched endovascular repair, Fenestrated EVAR, Branched EVAR, Juxtarenal aortic aneurysm.

Retroperitoneal vs transperitoneal approach for nonruptured open conversion after endovascular aneurysm repair

ObjectiveSeveral studies comparing the transperitoneal (TP) and retroperitoneal (RP) approach for abdominal aortic aneurysm (AAA) repair suggest that the RP approach may result in lower rates of perioperative mortality and morbidity. However, data comparing these approaches for open conversion are lacking. This study aims to evaluate the association between the type of approach and outcomes following open conversion after endovascular aneurysm repair (EVAR). MethodsWe included all patients who underwent open conversion after EVAR between 2010 and 2022 in the Vascular Quality Initiative. Patients presenting with rupture were excluded. The primary outcome was perioperative mortality. The secondary outcomes included perioperative complications and 5-year mortality. Inverse probability weighting was used to adjust for factors with statistical or clinical significance. Logistic regression was used to assess perioperative mortality and complications in the weighted cohort. The 5-year mortality was evaluated using Kaplan-Meier and Cox regression. ResultsWe identified 660 patients (39% RP) who underwent open conversion after EVAR. Compared with TP, RP patients were older (75 years [interquartile range, 70-79 years] vs 73.5 years [interquartile range, 68-79 years]; P < .001), and more frequently had prior myocardial infarction (33% vs 22%; P = .002). Compared with the TP approach, the RP approach was used less frequently in cases of associated iliac aneurysm (19% vs 27%; P = .026), but more frequently with associated renal bypass (7.8% vs 1.7%; P < .001) and by high-volume physicians (highest quintile, >7 AAA annually: 41% vs 17%; P < .001) and in high-volume centers (highest quintile, >35 AAA annually: 36% vs 20%; P < .001). RP patients, compared with TP patients, were less likely to have external iliac or femoral distal anastomosis (8.2% vs 21%; P < .001), and an infrarenal clamp (25% vs 36%; P < .001). Unadjusted perioperative mortality was not significantly different between approaches (RP vs TP: 3.8% vs 7.5%; P = .077). After risk adjustment, RP patients had similar odds of perioperative mortality (adjusted odds ratio [aOR], 0.49; 95% confidence interval [CI], 0.22-1.10; P = .082), and lower odds of intestinal ischemia (aOR, 0.26; 95% CI, 0.08-0.86; P = .028) and in-hospital reintervention (aOR, 0.43; 95% CI, 0.22-0.85; P = .015). No significant differences were found in the other perioperative complications or 5-year mortality (aHR, 0.79; 95% CI, 0.47-1.32; P = .37). ConclusionsOur findings suggest that the RP approach may be associated with a lower adjusted odds of perioperative complications compared with the TP approach. The RP approach should be considered for open conversion after EVAR when feasible.

Feasibility of contrast-enhanced ultrasound in the detection and classification of endoleaks after endovascular aneurysm repair.

Endoleaks are common complications after endovascular aneurysm repair (EVAR) for abdominal aortic aneurysm (AAA). Computed tomographic angiography (CTA)/digital subtraction angiography (DSA) is considered the gold standard for evaluating contrast-enhanced ultrasound (CEUS) accuracy in the detection and classification of endoleaks. In recent years, CEUS has been widely used in this field. This study aimed to analyze the accuracy of CEUS in the detection and classification of endoleaks after EVAR. The data of 98 patients who underwent abdominal aorta CEUS from November 2017 to September 2023 in the ultrasound (US) department of Beijing Hospital were retrospectively analyzed. All the patients underwent EVAR of AAA before CEUS and CTA/DSA, and had complete clinical data. The CEUS and CTA/DSA results were compared to detect endoleaks and categorize the specific types of endoleaks. Among the 98 patients, 74 were male and 24 were female. The patients had an average age of 74.8±9.8 years (range, 43-90 years). Among the 98 patients, 37 (37.8%) endoleaks were detected by CEUS, of which 8 were type Ia, 2 were type Ib, 15 were type II, 7 were type III, 2 were type IV, 2 were type Ia combined with type III, and 1 was type II combined with type III. In addition, among these 98 patients, 39 (39.8%) endoleaks were detected by CTA/DSA, of which 8 were type Ia, 3 were type Ib, 18 were type II, 6 were type III, 2 were type Ia combined with type III, 1 was type II combined with type III, and 1 was type Ib combined with type II. The sensitivity and specificity of CEUS in the detection of endoleaks were 92.3% and 98.3%, respectively. CEUS and CTA/DSA had similar diagnostic efficacy and good consistency in the detection and classification of endoleaks (Kappa value: 0.914, P<0.01). CEUS has high sensitivity and specificity in the detection and classification of endoleaks following EVAR, and its diagnostic efficacy is similar to that of CTA/DSA. In addition, US is safe, non-invasive and repeatable, and thus is worthy of extensive clinical application.