Management Of Abdominal Aortic Aneurysms Research Articles

Chemical stabilization of the extracellular matrix attenuates growth of experimentally induced abdominal aorta aneurysms in a large animal model

ObjectiveThe goal of the present study was to test the safety and efficacy of chemical stabilization of the arterial extracellular matrix as a novel nonoperative treatment of abdominal aortic aneurysms (AAAs) in a clinically relevant large animal model. MethodsTo achieve matrix stabilization, we used 1,2,3,4,6-pentagalloylglucose (PGG), a noncytotoxic polyphenolic agent capable of binding to and stabilizing elastin and collagen against the action of degrading enzymes. We first optimized the therapeutic PGG formulation and time of exposure by in vitro testing on porcine aortas using phenol histologic staining with iron chloride, elastic recoil assays, and PGG quantification as a function of tissue thickness. We then induced AAAs in 16 swine using sequential balloon angioplasty and elastase/collagenase and calcium chloride treatment of the infrarenal segment. We monitored AAA induction and development using digital subtraction angiography. At 2 weeks after induction, after the AAAs had reached ∼66% arterial expansion, the swine were randomly assigned to 2 groups. In the treatment group, we delivered PGG to the aneurysmal aorta endoluminally using a weeping balloon and evaluated the AAA diameters using digital subtraction angiography for another 10 weeks. The control swine did not receive any treatment. For the safety evaluation, we collected blood and performed comprehensive metabolic panels and complete blood counts every 2 to 3 weeks for all the animals. The swine were routinely monitored for neurologic and physical attributes such as behavior, inactivity, alertness, appetite, discomfort, and weight gain. After euthanasia and full necropsy, we analyzed the AAA tissue samples for PGG content, elastic recoil, and histologic features. ResultsIn vitro, a single 2.5-minute intraluminal delivery of 0.3% PGG to the swine aorta was sufficient for PGG to diffuse through the entire thickness of the porcine arterial tissues and to bind with high affinity to the elastic lamellae, as seen by positive iron chloride staining, a reduction of elastic recoil, and an increase in PGG content. In vivo, the control swine AAA tissues were thickened and showed the typical aspects of AAA, including chronic inflammation, adventitial reactivity, smooth muscle cell proliferation, elastic lamellae degradation, and medial and adventitial calcification. Similar aspects were noted in the PGG-treated arteries, except for the lack of calcification and an apparent diminished hyperplasia. PGG treatment was effective in reducing AAA expansion and reversing the process of AAA dilation by reducing the aortic diameters to ≤30% by week 12 (P < .05). PGG was specifically localized to the aneurysmal segments as seen by histologic examination, the reduction of elastic recoil, and an increase in PGG content. PGG treatment did not affect the swine's neurologic or physical attributes, weight, blood chemistry, blood cells, or functionality of remote organs. The control, untreated swine exhibited progressive increases in AAA diameters up to a mean value of 104%. ConclusionsLocalized delivery of PGG to the aneurysmal aorta attenuated AAA growth and reversed the course of the disease in the swine AAA model. Such specificity for diseased tissue is unprecedented in nonoperative AAA treatment. This novel paradigm-shifting approach has the potential to revolutionize AAA management and save thousands of lives.

Spatial Distribution of Abdominal Aortic Aneurysm Surface Growth and Correlation with Diameter and Volume Expansion

Introduction - The management of Abdominal Aortic Aneurysms (AAAs) is currently based on maximum size and growth rate criteria. Large or rapidly growing AAAs are thought to be at an increased risk of rupture, thus being suitable for intervention. Size and growth are determined based on the maximum diameter alone. Nevertheless, this variable takes into account a single portion of the vessel, while expansion is non-uniform, characterized by significant spatial variability. We aim to quantify regional surface growth of a cohort of AAAs. Methods - This is a single institution study including 31 lesions. Each AAA should have at least one baseline and one follow-up CT scan. From those, 3-Dimensional AAA models were created by semi-automated segmentation using dedicated software. Maximum orthogonal diameter and total aneurysm volume were recorded and used to calculate annual growth rate. Regional surface growth was quantified using the VascForm algorithm, which is written in Matlab, adapted to aneurysm follow-up studies and has been recently validated.[1] In general it is based on non-rigid point cloud registration and the iterative closest point algorithm. Initially, surfaces are pre-aligned applying principal component analysis and a general deformation of the Source surface is performed in order to best match the Target. Then, the surfaces are finely matched through a non-rigid local deformation model and each point in the Source surface is placed closer to the Target surface. After the registration, the surface growth distribution is the discretized surface element growth distribution. Maximum and average surface growth were calculated and correlated with the diameter and volume growth rate. The Spearman rho correlation coefficients were calculated and the statistical significance was tested using a two-tailed test. In order to identify potential correlation between intraluminal thrombus deposition (ILT) and surface growth, the co-localization of maximum surface growth with initial ILT maximum thickness was examined. Results - Median annual surface growth was 6.7%(0%>68%) and maximum surface growth was 26%(12%>444%). Correlations between surface and diameter/volume growth are summarized in Table 1. In 48% of follow-ups (15/31), maximum surface growth occurred away from the site of maximum diameter and thus could not have been captured by the measurement of maximum diameter growth. Sixteen cases presented maximum surface growth away and fifteen at the region of maximum initial ILT thickness. AAAs in the former group had significantly lower initial ILT thickness (11.3 vs 19.5mm, p<0.001) compared to those in the latter.Tabled 1DmaxVolumeMaxSurfaceCorrelationCoefficient,465,544Sig. (2-tailed),014,009AvgSurfaceCorrelationCoefficient,389,866Sig. (2-tailed),045,000 Open table in a new tab Conclusion - Regional surface growth of AAAs is not uniform. Average and maximum surface growth are related to the diameter growth but the correlation is only moderate. Volume growth presents very strong correlation with average but only moderate correlation with maximum surface growth rate. Almost half of the lesions display maximum surface growth at a site different from that of maximum diameter. Regional growth is related to initial local amount of ILT. Surface growth provides a means to evaluate spatial distribution of AAA expansion which may be of value for rupture risk predictions. References Metaxa E, Iordanov I, Maravelakis E, Papaharilaou Y. A novel approach for local abdominal aortic aneurysm growth quantification. Medical & Biological Engineering. DOI 10.1007/s11517-016-1592-8.

Endovascular Aneurysm Sealing (EVAS). Outcomes and Anatomical Suitability, a Single Centre Experience.

Introduction: EVAS has been introduced in 2013, since then the instructions for use (IFU) have changed in order to improve safety of the technique. The most significant changes were a maximum neck diameter reduction to 28mm and a ratio of maximum aortic aneurysm diameter to maximum aortic blood lumen <1,4. The aim of this study is firstly to assess the suitability of EVAS and to report our preliminary results of elective repair of abdominal aortic aneurysm (AAA) using the original IFU. Secondly we want to identify if the patients of our original cohort would have also been suitable for EVAS using the new IFU. Methods: We have investigated all patient treated with EVAS between June 2013 and December 2016. All patients undergoing elective AAA repair where eligible to enter the analysis. We have identified age, co-morbidity, aneurysm size, anatomical morphology, mortality and complications. Patients were followed until October 2017. Regular Follow up consists of routine computertomograpy angiogram and Doppler ultrasound. Of each included patient, we investigated if the aneurysm morphology would still make them suitable to undergo EVAS repair under the new IFU. Results: 61 patients (median age 77,5 years, range 56-90; 51 men) with an abdominal aortic aneurysm were treated with the Nellix EVAS system at our institution. The median aneurysm diameter was 60mm (range 53-82). Aneurysm morphology was compliant in 47 patients (77%) with the old IFU and 11 patients (18%) with the new IFU. The majority of cases 42 (69%) were not suitable because of a high ratio between thrombus and flow lumen (≥ 1,4). Patients were followed up until the first October 2017 or date of death. Median follow up was 33 months. In follow up we identified 13 (21%) type 1A endoleaks of which 5 patients were inside the new IFU, 4 (7%) ruptures, and 4 (7%) limb occlusions. Overall mortality was 18% of which 10% (6 patients) was aneurysm related and 7% (4 patients) died of unknown cause. Conclusion: In conclusion EVAS with the new IFU for the management of AAA is only suitable for a small percentage of our patients and in our cohort there was a high mortality rate and incidence of Type 1a endoleaks.

Contemporary Analysis of Intact Abdominal Aortic Aneurysm Repair by Treatment Method

Introduction: The long-term results of the landmark randomised trials comparing EVAR and open aneurysm repair (OAR) were challenged when recent recommendations of abdominal aortic aneurysm management were being based on them. In the last two decades since those trials were conducted, improvement in perioperative medicine, refined patient selection and advances in graft technology resulted in lower operative mortality. However, the impact of EVAR and OAR on long-term patient survival has been controversial (1, 2). The aim of this study was to compare the outcomes of OAR and EVAR in the recent era. Methods: This was an observational study. Both national administrative and clinical vascular databases were interrogated to capture all patients that underwent a planned AAA repair from the 1st of January 2010 until the 31st of December 2014. The data was matched by using unique patient identifying numbers, and death dates were obtained from national mortality database. Open repair and EVAR using 2nd 3rd generation endografts were included, trial devices and fenestrated/branched configuration were excluded. Logistic regression models were used to determine predictors of 30-day mortality, and Cox proportional hazards model was used to determine predictors of survival. The censoring date for survival analysis was the 31st of January 2018. The national ethics committee approved this study. Results: Overall, 1220 patients underwent aneurysm repair, of which 62 patients were excluded. The mean age was 74 years and 218 (18.2%) patients were females. There were 615 (53.1%) patients on whom an EVAR was performed and the median (interquartile range) AAA diameter was 61 (55-70)mm. The 30-day mortality after OAR and EVAR was 3.5% and 0.7% respectively (adjusted OR: 5.5 [95%CI:1.8-16.4]). The median and maximum follow-up was 4.5 and 8 years respectively. The crude survival curves crossed at 18 months and after adjusting for confounders, EVAR was associated with a HR 1.5 (95%CI:1.2-1.9). Patients who underwent an EVAR had a higher aneurysm-related mortality. Other prognostic factors that were also associated with a lower survival rate were: increased age, being female, and having renal impairment and ischaemic heart disease. Conclusion: In this real world setting using the current endografts devices and technology, patients who underwent EVAR enjoyed a lower short mortality but this benefit disappeared at 2 years follow-up. OAR had a higher survival rate in the long term. Disclosure: Nothing to disclose

Ultrasound Surveillance of Common Iliac Artery Aneurysms

The surveillance of patients with common iliac artery aneurysms (CIAA) does not follow a defined protocol such as the one adopted for the management of abdominal aortic aneurysms. This study explores CIAA growth rate, and seeks to determine correlations with related parameters which may serve to influence aneurysm expansion with the view of devising an effective local surveillance protocol. Vascular laboratories across the UK were invited to participate in an online survey. Questions were designed to assess current clinical practice in regards to the surveillance of patients with CIAA. Additionally, a retrospective audit was performed using the clinical reports of patients attending a regional vascular laboratory to undergo an aorto-iliac duplex scan (USS). Expansion rate of aneurysms was studied in patients who had ≥2 USS scans; data was recorded at 6 and/or 12 monthly intervals up to 5years. Kaplan Meier estimates of patient mortality (all cause) and intervention rate during the surveillance period were performed. Patient age, initial CIAA diameter, bilateral/unilateral CIAA and coinciding aortic aneurysm diameter were recorded to determine if these specific features were associated with CIAA growth rates. Pearson's correlation coefficient was used to determine the strength of association between variables. Nine hundred and ninety-five of one thousand and sixty patient records were suitable for review: 21.6% (215/995) of patients had a CIAA. Isolated CIAA accounted for 23% (50/215). Mean CIAA growth was 1.5±0.3mm/year. A strong correlation was found between CIAA diameter versus time from diagnosis (r=0.820; P=0.004); CIAA with smaller initial diameters (15-20mm) expanded more rapidly than those of larger diameter at diagnosis (r=0.871; P=0.005). CIAA measured at >30mm demonstrated an unpredictable growth trajectory which was also evident in those CIAA coinciding with larger AAA (>50mm; r=0.208; P=0.655). The results obtained in this study may form the basis for a dedicated CIAA surveillance protocol.

Updates on Ultrasonography Imaging in Abdominal Aortic Aneurysm.

Abdominal aortic aneurysms (AAAs) are life-threatening and are associated with >80% mortality when they rupture. Therefore, detecting these aneurysms before they rupture is critical. Ultrasonography is a non-invasive tool that is used for screening AAAs by measuring abdominal aorta diameter. A recent meta-analysis demonstrated the positive effects of ultrasonography. To date, aneurysm diameter is the most reliable predictor for aneurysm rupture and is used as a criterion for surgical intervention. However, some AAAs rupture at small diameters. Therefore, a better predictor for AAA rupture that is independent of aneurysm diameter is needed. Recently, an aortic wall strain examined using ultrasonography has been reported to have a potential in predicting AAA rupture. Since the introduction of endovascular aneurysm repair (EVAR), a paradigm shift has occurred in the management of AAAs. EVAR is broadly spread with the advantage of early favorable results but with concerning endoleak complications. At present, computed tomography angiography (CTA) is considered to be a gold standard for surveillance following EVAR, but it encounters some problems, such as contrast usage or radiation exposure. Ultrasonography offers an examination free from these problems and can this be an alternative to CTA. In this review article, current trends and new technologies regarding AAA assessment using ultrasonography are introduced.

Management of abdominal aortic aneurysm and concomitant malignant disease.

Concomitant malignant disease and abdominal aortic aneurysms (AAA) represent a challenging issue in terms of treatment priority, timing and perspectives. This systematic review provides an overview of the available literature about AAA and concomitant malignant disease. We conducted a literature search of all the English-language medical literature in Medline (through PubMed), Embase, Clinical Trial databases and the Cochrane Library up to December 31st, 2018. The literature about AAA and concomitant malignant disease is mostly based on retrospective small case series. Two recently published meta-analyses focusing on the management of AAA and concomitant abdominal neoplasms came to the same conclusion "treat what is most threatening or symptomatic first." The threshold to treat asymptomatic AAA should not be altered in patients with AAA and concomitant cancer including cases under chemotherapy. An asymptomatic AAA of at least 55 mm anatomically suitable for EVAR, should only be treated first in patients with at least a life expectancy of two years followed by staged cancer surgery two weeks later. Decisions about management of AAA and concomitant malignant disease should be based on clinical judgment applied individually in a multidisciplinary setting ("treat first what kills first"). The indication for treatment is not different than in patients with AAA without cancer. A staged approach is preferable and ideally the AAA should be excluded by endovascular means if anatomically suitable. An international registry should be initiated to gather more evidence about the management and outcomes of patients with AAA and concomitant carcinoma.

Variation in the elective management of small abdominal aortic aneurysms and physician practice patterns

ObjectiveRecent vascular societal guidelines have recommended an abdominal aortic aneurysm (AAA) size threshold for elective intervention; however, limited data have documented how well these AAA diameter benchmarks are being met. The objective of this study was to analyze variation in management of AAAs based on diameter and to determine the physician's rationale for intervention on small AAAs in relation to recommended treatment guidelines. MethodsA retrospective review of a statewide vascular surgery registry of all elective endovascular or open surgical AAA repairs from January 2012 to January 2016 was performed. Patients were dichotomized on the basis of aortic diameter at time of intervention into either guideline size AAAs or small AAAs, which were defined as <5.5 cm in men, <5.0 cm in women, or with growth <1.0 cm/y. An internal review was conducted of all small AAAs to determine the physician's rationale for intervention. The primary outcomes were variation in adherence to recommended treatment guidelines and the physician's rationale for treatment of small AAAs. Risk-adjusted major complication and mortality rates were calculated at 30 days and 1 year using a propensity score matching analysis. ResultsAmong the 3932 patients who underwent an elective AAA repair, 485 (12.3%) were repaired at diameters smaller than recommended by guidelines. The median AAA size in the small AAA cohort was 5.1 cm (interquartile range, 4.7-5.3 cm) vs 5.6 cm (interquartile range, 5.2-6.1 cm) in the guideline-based group. Percentage of small AAA repairs varied widely between hospitals from 1.4% to 44.4%. The physician's rationale for the majority of early interventions included the patient's anxiety (12.0%), combined aortoiliac occlusive disease (14.8%), aneurysm anatomy (28.2%), and does not adhere to guidelines (30%). The small AAA cohort had no significant difference in the 30-day or 1-year risk-adjusted mortality in comparison to guideline size AAAs. ConclusionsDespite well-established aortic diameter threshold guidelines, marked variation exists both at the hospital level and in terms of the physician's rationale for the management of elective AAA repairs. These findings demonstrate the challenge of providing uniform care for patients with AAAs despite established guidelines.

Management of air bubble within the excluded aneurysm sac in the early period after endovascular management of abdominal aortic aneurysm

Management of air bubble within the excluded aneurysm sac in the early period after endovascular management of abdominal aortic aneurysm

Abdominal Aortic Aneurysm Segmentation Using Convolutional Neural Networks Trained with Images Generated with a Synthetic Shape Model.

An abdominal aortic aneurysm (AAA) is a ballooning of the abdominal aorta, that if not treated tends to grow and rupture. Computed Tomography Angiography (CTA) is the main imaging modality for the management of AAAs, and segmenting them is essential for AAA rupture risk and disease progression assessment. Previous works have shown that Convolutional Neural Networks (CNNs) can accurately segment AAAs, but have the limitation of requiring large amounts of annotated data to train the networks. Thus, in this work we propose a methodology to train a CNN only with images generated with a synthetic shape model, and test its generalization and ability to segment AAAs from new original CTA scans. The synthetic images are created from realistic deformations generated by applying principal component analysis to the deformation fields obtained from the registration of few datasets. The results show that the performance of a CNN trained with synthetic data to segment AAAs from new scans is comparable to the one of a network trained with real images. This suggests that the proposed methodology may be applied to generate images and train a CNN to segment other types of aneurysms, reducing the burden of obtaining large annotated image databases.

Stent graft coverage of dual-stent strategy in the management of abdominal aortic aneurysms

Treating an abdominal aortic aneurysm (AAA) with a stent graft (SG) and a multilayer stent (MS) is a key technology in isolating flow fields. Clinically, dual stents (an SG in the proximal and an MS in the distal of AAA) are used for treatment of AAA, but only a few studies have examined the relationship between SG coverage and treatment effects. Through numerical simulation of the hemodynamics after SG and MS implantation, the SG coverage and position were simulated at 0% (0 mm), 25% (13.75 mm), 50% (27.5 mm), and 75% (41.25 mm). With increasing SG coverage, the pressure on the aneurysm sac wall and the flow of branch vessels gradually decreased, and the lower wall shear stress (WSS) gradually increased. The changes in pressure, lower WSS, and the mass flow rate of the branch vessels did not change significantly. The coverage of the SG has a nonsignificant effect on hemodynamics in the treatment of AAA; the implantation position need not be very precise. This research can provide theoretic support for clinicians’ decision-making.

Randomized Placebo-Controlled Trial Assessing the Effect of 24-Week Fenofibrate Therapy on Circulating Markers of Abdominal Aortic Aneurysm: Outcomes From the FAME -2 Trial.

BackgroundThere is no drug therapy for abdominal aortic aneurysm (AAA). FAME‐2 (Fenofibrate in the Management of Abdominal Aortic Aneurysm 2) was a placebo‐controlled randomized trial designed to assess whether administration of 145 mg of fenofibrate/d for 24 weeks favorably modified circulating markers of AAA.Methods and ResultsPatients with AAAs measuring 35 to 49 mm and no contraindication were randomized to fenofibrate or identical placebo. The primary outcome measures were the differences in serum osteopontin and kallistatin concentrations between groups. Secondary analyses compared changes in the circulating concentration of AAA‐associated proteins, and AAA growth, between groups using multivariable linear mixed‐effects modeling. A total of 140 patients were randomized to receive fenofibrate (n=70) or placebo (n=70). By the end of the study 3 (2.1%) patients were lost to follow‐up and 18 (12.9%) patients had ceased trial medication. A total of 85% of randomized patients took ≥80% of allocated tablets and were deemed to have complied with the medication regimen. Patients’ allocated fenofibrate had expected reductions in serum triglycerides and estimated glomerular filtration rate, and increases in serum homocysteine. No differences in serum osteopontin, kallistatin, or AAA growth were observed between groups.ConclusionsAdministering 145 mg/d of fenofibrate for 24 weeks did not significantly reduce serum concentrations of osteopontin and kallistatin concentrations, or rates of AAA growth in this trial. The findings do not support the likely benefit of fenofibrate as a treatment for patients with small AAAs.Clinical Trial Registration URL: http://www.anzctr.org.au. Unique identifier: ACTRN12613001039774.

Editor's Choice – Mid-term Migration and Device Failure Following Endovascular Aneurysm Sealing with the Nellix Stent Graft System – a Single Centre Experience

Endovascular aneurysm sealing (EVAS) with the Nellix stent graft system is a novel concept in the management of abdominal aortic aneurysm (AAA) that aims to reduce the prevalence of all endoleaks following endovascular repair. There are few data describing the longer-term durability of this approach. The aim was to report the longer-term outcomes following EVAS in a single centre. This is a retrospective review of all patients that underwent Nellix at Cambridge University Hospitals Foundation Trust. Factors that are described as device failure include secondary sac rupture, graft explantation, further surgical procedures for Type 1 endoleak, or major migration of the stent grafts with pressurisation of the aortic sac. A total of 161 patients have been treated with Nellix. The indications included primary AAA (n=115), ruptured AAA (n=4), salvage of other aortic grafts (n=18), primary iliac aneurysm (n=6), and chimney EVAS (ChEVAS) for pararenal AAA (n=18). In total there have been 42 graft failures in patients treated with EVAS for primary AAA. The 4 year freedom from graft failure was 42% in patients treated for primary AAA. Failures mostly occurred more than 2 years post-Nellix implant. There were eight secondary sac ruptures (incidence 2.4 per 100 person years) and there have been 14 graft explants. Failure of aneurysm sealing following treatment with Nellix has been more common than anticipated and can cause aortic rupture. Post-operative surveillance of Nellix stent grafts is crucial to identify features of failure.

Invited commentary

Invited commentary

Fenofibrate and Telmisartan in the Management of Abdominal Aortic Aneurysm.

This mini-review provides the rationale and updated progress for ongoing randomized controlled trials assessing fenofibrate and telmisartan efficacy to limit abdominal aortic aneurysm (AAA) growth. There remains an urgent need to identify a drug therapy that will limit AAA growth. Data from preclinical and human studies indicate that fenofibrate and telmisartan have the potential to slow aortic destruction. Fenofibrate has been shown to reduce serum and tissue levels of the proinflammatory protein osteopontin, as well as reducing macrophage recruitment to the aortic wall, both of which are integral processes in the development and progression of AAAs. Telmisartan acts via blockade of the angiotensin II receptor, type 1, and also as a peroxisome proliferator-activated receptor gamma agonist. In turn, this inhibits the production of a range of biomarkers associated with AAA progression, including transforming growth factor-beta one, osteoprotegerin, osteopontin and matrix metalloproteinase- 9. Based on these findings, there are currently three randomized controlled trials assessing both fenofibrate and telmisartan as potential interventions to limit aneurysm growth in AAA patients. Fenofibrate and telmisartan have potential as repurposed medications to limit AAA growth, and randomized trials for further assessment in AAA patients are ongoing.

Geometric surrogates of abdominal aortic aneurysm wall mechanics

The maximum diameter criterion is the most important factor in the clinical management of abdominal aortic aneurysms (AAA). Consequently, interventional repair is recommended when an aneurysm reaches a critical diameter, typically 5.0 cm in the United States. Nevertheless, biomechanical measures of the aneurysmal abdominal aorta have long been implicated in AAA risk of rupture. The purpose of this study is to assess whether other geometric characteristics, in addition to maximum diameter, may be highly correlated with the AAA peak wall stress (PWS). Using in-house segmentation and meshing algorithms, 30 patient-specific AAA models were generated for finite element analysis using an isotropic constitutive material for the AAA wall. PWS, evaluated as the spatial maximum of the first principal stress, was calculated at a systolic pressure of 120 mmHg. The models were also used to calculate 47 geometric indices characteristic of the aneurysm geometry. Statistical analyses were conducted using a feature reduction algorithm in which the 47 indices were reduced to 11 based on their statistical significance in differentiating the models in the population (p < 0.05). A subsequent discriminant analysis was performed and 7 of these indices were identified as having no error in discriminating the AAA models with a significant nonlinear regression correlation with PWS. These indices were: Dmax (maximum diameter), T (tortuosity), DDr (maximum diameter to neck diameter ratio), S (wall surface area), Kmedian (median of the Gaussian surface curvature), Cmax (maximum lumen compactness), and Mmode (mode of the Mean surface curvature). Therefore, these characteristics of an individual AAA geometry are the highest correlated with the most clinically relevant biomechanical parameter for rupture risk assessment. We conclude that the indices can serve as surrogates of PWS in lieu of a finite element modeling approach for AAA biomechanical evaluation.

Abdominal aortic aneurysm management: Are clinical staff aware of the screening programme?

Abdominal aortic aneurysm management: Are clinical staff aware of the screening programme?

TARGETING ENDOPLASMIC RETICULUM STRESS AS A THERAPY TO MANAGE ABDOMINAL AORTIC ANEURYSM DISEASE

Objective: Abdominal aortic aneurysm (AAA) is a degenerative vascular disease with high morbidity and mortality. It has a prevalence of 4–8% in men over the age of 65 years that is increasing in association with the aging population. Clinical management of AAA is limited to elective surgical repair while an effective pharmacotherapy is awaited. Therefore, we aim to determine whether inhibition of endoplasmic reticulum stress is an effective therapy to reduce aortic wall degeneration occurring in AAA. Design and method: The endoplasmic stress activation was studied by real Time PCR, Western Blot and by immunostaining in a cohort of AAA samples from 100 patients compared with abdominal aorta from 20 healthy donors and in abdominal aorta of a mouse model of AAA (apolipoprotein E–deficient mice infused with angiotensin II for 4 weeks with osmotic minipumps). In males and females mice, the aortic diameter was monitored and recorded by ultrasonography at 0, 7, 14, 21 and 28 days of Ang II infusion and blood pressure was measured by tail-cuff method. The phenylbutyrate sodium or PBA and Tauroursodeoxycholic Acid or Tudca as classic endoplasmic reticulum stress inhibitors, were administered intraperitoneally for 3 days a week to hipertensive mice. Results: In human AAA the endoplasmic reticulum stress induction was assessed by enhanced expression of ATF6, IRE-1, XBP-1 and CHOP and by an increase in protein expression of active ATF6 and XBP1 and of the pro-apoptotic protein CHOP. This was accompanied by an exacerbated apoptosis in vascular wall measured by TUNEL and by cleaved caspase-3 and by an increase in NADPH oxidase expression and in superoxide anion production. In the abdominal aorta of the murine AAA model the gene expression of ATF4, GRP78 and IRE-1 was increased while no differences were found in ATF6 or CHOP between AAA and control mice. The administration of PBA and Tudca decreased the incidence of AAA by reducing the abdominal aortic dilatation, systolic blood pressure and aorta wall disorganization. Conclusions: Our results evidence that inhibition of ER stress is a potential therapy to reduce aortic dilatation and medial wall destruction in AAA.

Management of Abdominal Aortic Aneurysms with Atypical Renal Artery Anatomy

Renal artery anomalies occur at a rate of 1-2% and present a challenge to aortic surgeons. We describe adjuncts used to manage such anatomic variants.

Resultados preliminares en el análisis de elementos finitos de aneurismas de aorta abdominal en rango no quirúrgico

IntroductionThe diagnosis and management of abdominal aortic aneurysms currently relies on the maximal aortic diameter, which grows in an unpredictable manner. The aim of this study was to compare the results of the biomechanical variables using finite elements analysis between the 2 groups of small aneurysms (group I 40-49mm, group II 50-54mm). MethodsA total of 23 patients with abdominal aortic aneurysm (group I N=14, group II N=9) who had undergone a thoraco-abdominal angio computed tomography in this hospital were prospectively identified. Abdominal aortic aneurysms diameter, peak wall rupture (PWR), PWR Index, Rupture Risk Equivalent Diameter (RRED) abdominal aortic aneurysms and thrombus volume were measured and calculated using finite element analysis software. The variability between maximum abdominal aortic aneurysms diameter and RRED was also determined. ResultsAn increased PWS, PWRR, and RRED, was observed in group II. Moreover, 5 (21.74%) patients had a positive variability (>0.5mm), and 2 of them (8.70%) had a PWRR >0.5, which is associated with a higher aneurysm rupture risk. ConclusionPWR and PWRR are elevated in group II, perhaps secondary to a larger abdominal aortic aneurysms diameter. Further studies are required before using this software in clinical decisions.