Epidemiology and potential for prevention of abdominal aortic aneurysm

The effect of exercise training intervention for patients with abdominal aortic aneurysm on cardiovascular and cardiorespiratory variables: an updated meta-analysis of randomized controlled trials

OBJECTIVE

The purpose of this meta-analysis was to evaluate the effect of exercise training intervention in patients with abdominal aortic aneurysm (AAA).

METHODS

Eight randomized controlled trials (RCTs) that recruited 588 AAA patients were extracted using 4 databases (PubMed, Embase, Wanfang Data, and Cochrane Library). Physiological and biochemistry parameters that included in this study are high-sensitivity C-reactive protein (hs-CRP), respiratory peak oxygen uptake rate (VO2peak), triglyceride (TG), total cholesterol (TC), anaerobic threshold (AT), the diameter of AAA, high density lipoprotein cholesterol (HDL), low density lipoprotein cholesterol (LDL), and matrix metalloproteinase-9 (MMP-9). Standard mean difference (SMD) was used to assess the between group effect.

RESULTS

This meta-analysis was synthesized with findings from RCTs and found that hs-CRP (SMD, - 0.56 mg/dL; 95% CI: - 0.90 to 0.22; P = 0.001), VO2peak (SMD, 0.4 mL/kg/min; 95% CI, 0.21 to 0.60; P < 0.001), TG (SMD, - 0.39 mg/dL; 95% CI: - 0.02 to 0.77; P = 0.04), and AT (SMD, 0.75 mL/kg/min; 95% CI, 0.54 to 0.96; P < 0.001) were significantly improved in the exercise groups, while the size of AAA (SMD, - 0.15; 95% CI: - 0.36 to 0.06; P = 0.15), TC (SMD, 0.16 mg/dL; 95% CI: - 0.10 to 0.42; P = 0.23), HDL/LDL ratio (SMD, - 0.06; 95% CI: - 0.32 to 0.20; P = 0.64), HDL (SMD, - 0.09; 95% CI: - 0.39 to 0.20; P = 0.54), LDL (SMD, 0.08; 95% CI: - 0.21 to 0.38; P = 0.59), and MMP-9 (SMD, - 0.23 mg/dL; 95% CI: - 0.53 to 0.06; P = 0.12) did not differ in the exercise groups compared with the controls.

CONCLUSION

Exercise intervention improved some of the CVD risk factors but not all, hs-CRP, VO2peak and AT were significantly improved after exercise intervention, while, changes of MMP-9, the size of AAA, and the overall lipids profile were not. Exercise intervention provides an additional solution for improving cardiorespiratory capacity and health status among AAA patients, and might lead to a delay of AAA progression.

The Function and Therapeutic Potential of Circular RNA in Cardiovascular Diseases

Circular RNA (circRNA) has a closed-loop structure, and its 3' and 5' ends are directly covalently connected by reverse splicing, which is more stable than linear RNA. CircRNAs usually possess microRNA (miRNA) binding sites, which can bind miRNAs and inhibit miRNA function. Many studies have shown that circRNAs are involved in the processes of cell senescence, proliferation and apoptosis and a series of signalling pathways, playing an important role in the prevention and treatment of diseases. CircRNAs are potential biological diagnostic markers and therapeutic targets for cardiovascular diseases (CVDs). To identify biomarkers and potential effective therapeutic targets without toxicity for heart disease, we summarize the biogenesis, biology, characterization and functions of circRNAs in CVDs, hoping that this information will shed new light on the prevention and treatment of CVDs.

Ruptured Aortic Aneurysm and Dissection Related Death: an Autopsy Database Analysis

Acute aortic catastrophes (AAC), mainly ruptured aneurysms and dissections, lead all other vascular conditions in morbidity and mortality, even if intervention occurs. The aim of our study was to give a descriptive overview of the demographic and pathological characteristics of AAC. Between 1994 and 2013, 80,469 autopsies were performed at Semmelweis University hospitals in Budapest. After collecting the autopsy reports we were able to create the AAC database upon which we conducted our analysis. We found 567 cases of AAC. The cause of death in 120 of them was classified as a non-ruptured aorta with malperfusion or distal embolization. Of the remaining 447 cases, in 305 the cause of death was a ruptured aortic aneurysm (rAA), and in 142 it was a ruptured aortic dissection (rAD). The distribution of rAA cases was 34.4% thoracal, 4.3% thoracoabdominal, and 61.3% abdominal. We found female dominance where the rAA was thoracal. In rAD cases, 84% were Stanford A and 16% Stanford B type. In both groups we found different pathological distributions. In the prehospital group, the number of thoracal ruptures was considerable. 88% of the patients with Stanford A dissection died in the prehospital or perioperative period. The most progressive AACs were ruptures of intrapericardial aneurysms and Stanford A dissections., however survival rate can be elevated by using rapid imaging examination and immediate surgical intervention. We want to highlight that our study contains such gender differences, which are worth to be taken into consideration.

Circular RNA expression profile and its potential regulative role in human abdominal aortic aneurysm

Background

This study aimed to identify the differentially expressed circular RNAs (circRNAs) between human abdominal aortic aneurysm (AAA) and the control group.

Methods

High-throughput sequencing was applied to determine the circRNA expression profiles of 4 paired aortic samples. Real-time quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was carried out to testify 6 randomly selected dysregulated circRNAs. Kyoto Encyclopedia of Genes and Genomes and Gene ontology (GO) analysis were conducted for functional annotation of the parental genes. Additionally, interaction networks between circRNA and 5 putative microRNA (miRNA) partners were constructed.

Results

Finally, 411 differentially expressed circRNAs were discovered, including 266 downregulated and 145 upregulated circRNAs. Compared with the control group, the expression level of hsa (Homo sapiens) _circ_0005360 (LDLR) and hsa_circ_0002168 (TMEM189) were proved significantly lower in the AAA group by qRT-PCR. Regarding upregulated circRNAs, the most enriched GO molecular function, biological process and cellular component terms were poly(A) RNA binding, negative regulation of transcription from RNA polymerase II promoter and nucleoplasm, respectively. Moreover, circRNA/miRNA interaction networks showed that hsa_circ_0005360/miR-181b and hsa_circ_0002168/miR-15a axis might have a regulative role in human AAA.

Conclusions

This study revealed new circRNAs potentially related to the pathogenesis of AAA. Further experimental studies are warranted to clarify the potential molecular mechanisms.

Nationwide Epidemiologic Study of Abdominal Aortic Aneurysms in Korea: A Cross-Sectional Study Using National Health Insurance Review and Assessment Service Data

Purpose

The prevalence and treatment patterns of abdominal aortic aneurysm (AAA) vary according to ethnicity and region. This study analyzed nationwide data on the epidemiology, practice patterns, and mortality rates of AAA in Korea.

Materials and Methods

Data from patients treated for AAA from 2012 to 2016 were extracted from the Korean Health Insurance Review and Assessment (HIRA) database.

Results

A total of 30,766 patients in Korea had treatment codes for AAA and 2,618 patients were treated for ruptured AAA. Of the 6,356 patients treated surgically, 1,849 and 4,507 underwent open surgical aneurysmal repairs (OSAR) or endovascular aneurysmal repairs (EVAR), respectively. The number of surgical treatments performed annually for AAA increased from 1,129 cases in 2012 to 1,501 cases in 2016. The number of EVAR cases increased from 753 to 1,109 during these five years, while the number of OSAR cases remained similar, at 376 and 392, respectively. The 30-day mortality rates after EVAR and OSAR were 4.2% and 10.6%, respectively. The mortality rates were significantly higher in patients with hypertension, dyslipidemia, chronic renal disease, diabetes mellitus, and congestive heart failure. There were significant differences in the prevalence, proportion of EVAR, and mortality rates according to the regional area.

Conclusion

The prevalence of AAA and the proportion of EVAR in Korea increased in the past 5 years, while the rupture rate and the proportion of OSAR remained similar. To minimize mortality and regional discrepancies, nationwide registry and treatment standardization are needed.

Meta-analysis of the growth rates of abdominal aortic aneurysm in the Chinese population

Background

Several studies on the growth rates of abdominal aortic aneurysm (AAA) in Chinese population have been conducted; however, this issue remains unclear. The aim of this study is to systematically review published data of the AAA growth rates among people in China.

Methods

We conducted a comprehensive search of multiple databases to identify all studies of AAA growth in the Chinese population from inception until June 2017. AAA growth rates were combined to yield the growth rates at specified aneurysm diameter ranges, with using a random-effects model or fixed-effects model according to heterogeneity.

Results

A total of 8257 studies were initially identified and only 4 studies were eventually included. A random-effects analysis showed that the growth rates of AAA in Chinses population is ranging from 0.18 cm/year to 0.75 cm/year. The pooled mean growth rates among individuals with aneurysm measuring 3.0–3.9 cm, 4.0–5.9 cm and ≧ 6.0 cm in diameter were 0.21 cm/year (95% CI: 0.19 cm/year to 0.23 cm/year), 0.38 cm/year (95% CI: 0.33 cm/year to 0.43 cm/year), and 0.71 cm/year (95% CI: 0.64 cm/year to 0.77 cm/year) respectively. Further analysis found that the pooled mean growth rates for individuals with small AAA (diameters measuring 3.0–4.9 cm) was 0.28 cm/year (95% CI: − 0.06 cm/year to 0.61 cm/year)`and for individuals with large AAA (diameters ≥5.0 cm) was 0.75 cm/year (95% CI: 0.20 cm/year to 1.3 cm/year). Finally, meta-regression showed a strong trend of linear relationship between AAA growth rate and aneurysm diameter.

Conclusions

The growth rates of AAA in the Chinese population increase with AAA enlargement and appear to range from 0.18 cm/year in the smallest AAAs to 0.75 cm/year when the diameter exceeds 6 cm. However, based on current studies, it is difficult to estimate the accurate average AAA growth rate in Chinese patients. More large-scale, high-quality studies are required to achieve that. Overall, AAA growth rate increase with increased aneurysm diameter.

Electronic supplementary material

The online version of this article (10.1186/s12872-019-1160-x) contains supplementary material, which is available to authorized users.

Potential Medication Treatment According to Pathological Mechanisms in Abdominal Aortic Aneurysm

Abdominal aortic aneurysm (AAA) is a vascular disease with high mortality. Because of the lack of effective medications to stop or reverse the progression of AAA, surgical operation has become the most predominant recommendation of treatment for patients. There are many potential mechanisms, including inflammation, smooth muscle cell apoptosis, extracellular matrix degradation, oxidative stress, and so on, involving in AAA pathogenesis. According to those mechanisms, some potential therapeutic drugs have been proposed and tested in animal models and even in clinical trials. This review focuses on recent advances in both pathogenic mechanisms and potential pharmacologic therapies of AAA.

Anatomical location, sex, and age influence murine arterial circumferential cyclic strain before and during dobutamine infusion

Background

One of the primary biomechanical factors influencing arterial health is their deformation across the cardiac cycle, or cyclic strain, which is often associated with arterial stiffness. Deleterious changes in the cardiovascular system, e.g., increased arterial stiffness, can remain undetected until the system is challenged, such as under a cardiac stressor like dobutamine.

Purpose

To quantify cyclic strain in mice at different locations along the arterial tree prior to and during dobutamine infusion, while evaluating the effects of sex and age.

Study Type

Control/cohort study.

Animal Model

Twenty C57BL/6 mice; male, female; ∼12 and 24 weeks of age; n = 5 per group.

Field Strength/Sequence

7T; CINE MRI with 12 frames, velocity compensation, and prospective cardiac gating.

Assessment

Prior to and during the infusion of dobutamine, Green–Lagrange circumferential cyclic strain was calculated from perimeter measurements derived from CINE data acquired at the carotid artery, suprarenal and infrarenal abdominal aorta, and iliac artery.

Statistical Tests

Analysis of variance (ANOVA) followed by post‐hoc tests was used to evaluate the influence of dobutamine, anatomical location, sex, and age.

Results

Heart rates did not differ between groups prior to or during dobutamine infusion (P = 0.87 and P = 0.08, respectively). Dobutamine increased cyclic strain in each group. Within a group, increases in strain were similar across arteries. At the suprarenal aorta, strain was reduced in older mice at baseline (young 27.6 > mature 19.3%, P = 0.01) and during dobutamine infusion (young 53.0 > mature 36.2%, P = 0.005). In the infrarenal aorta, the response (dobutamine – baseline) was reduced in older mice (young 21.9 > mature 13.5%, P = 0.04).

Data Conclusion

Dobutamine infusion increases circumferential cyclic strain throughout the arterial tree of mice. This effect is quantifiable using CINE MRI. The results demonstrate that strain prior to and during dobutamine is influenced by anatomical location, sex, and age.

Level of Evidence: 3

Technical Efficacy: Stage 2

J. Magn. Reson. Imaging 2019;49:69–80.

Mobilization of the lumbar spine in a 76-year-old male with mechanical low back pain and an abdominal aortic aneurysm: A case report

BACKGROUND

Abdominal aortic aneurysms (AAAs) are found in 1-12% of older males. Low back pain (LBP) is prevalent with incidence increasing with age and can respond to manual therapy (MT). To date, the safety of the application of MT for LBP in the presence of a known AAA has not been reported. This case reports on the short-term effects of MT in a patient with LBP and AAA and pre- and post-therapy imaging.

CASE DESCRIPTION

A 76-year-old male presented with mechanical LBP, groin pain, and a known 4.2-cm AAA. A lumbar magnetic resonance imaging showed significant multilevel abnormalities. Abdominal screening did not elicit back or groin pain. Lumbar and hip range of motion and accessory motion testing reproduced his complaints. He was treated with lumbar and hip MT.

OUTCOMES

After three visits, he reported that his groin pain resolved, and his back pain could be managed with home exercise. He reported a +6 on the global rating of change. Repeated follow-up imaging of his AAA demonstrated no significant change of his AAA.

DISCUSSION

No immediate adverse events were recorded, and repeated follow-up imaging indicated no significant AAA expansion. Considering that mobilization causes similar displacement to active motion, research into the safety of MT in this population is warranted as are guidelines for appropriate initial and ongoing clinical screening during treatment in this population.

Deficiency of FAM3D (Family With Sequence Similarity 3, Member D), A Novel Chemokine, Attenuates Neutrophil Recruitment and Ameliorates Abdominal Aortic Aneurysm Development

Supplemental Digital Content is available in the text.

Objective—

Chemokine-mediated neutrophil recruitment contributes to the pathogenesis of abdominal aortic aneurysm (AAA) and may serve as a promising therapeutic target. FAM3D (family with sequence similarity 3, member D) is a recently identified novel chemokine. Here, we aimed to explore the role of FAM3D in neutrophil recruitment and AAA development.

Approach and Results—

FAM3D was markedly upregulated in human AAA tissues, as well as both elastase- and CaPO₄-induced mouse aneurysmal aortas. FAM3D deficiency significantly attenuated the development of AAA in both mouse models. Flow cytometry analysis indicated that FAM3D^−/− mice exhibited decreased neutrophil infiltration in the aorta during the early stage of AAA formation compared with their wild-type littermates. Moreover, application of FAM3D-neutralizing antibody 6D7 through intraperitoneal injection markedly ameliorated elastase-induced AAA formation and neutrophil infiltration. Further, in vitro coculture experiments with FAM3D-neutralizing antibody 6D7 and in vivo intravital microscopic analysis indicated that endothelial cell–derived FAM3D induced neutrophil recruitment. Mechanistically, FAM3D upregulated and activated Mac-1 (macrophage-1 antigen) in neutrophils, whereas inhibition of FPR1 (formyl peptide receptor 1) or FPR2 significantly blocked FAM3D-induced Mac-1 activation, indicating that the effect of FAM3D was dependent on both FPRs. Moreover, specific inhibitors of FPR signaling related to Gi protein or β-arrestin inhibited FAM3D-activated Mac-1 in vitro, whereas FAM3D deficiency decreased the activation of both FPR-Gi protein and β-arrestin signaling in neutrophils in vivo.

Conclusions—

FAM3D, as a dual agonist of FPR1 and FPR2, induced Mac-1-mediated neutrophil recruitment and aggravated AAA development through FPR-related Gi protein and β-arrestin signaling.

An evaluation of the effect of an angiotensin-converting enzyme inhibitor on the growth rate of small abdominal aortic aneurysms: a randomised placebo-controlled trial (AARDVARK)

BACKGROUND

Although data are inconsistent, angiotensin-converting enzyme inhibitors (ACE-Is) have been associated with a reduced incidence of abdominal aortic aneurysm (AAA) rupture in analysis of administrative databases.

OBJECTIVES

(1) To investigate whether or not the ACE-I perindopril (Coversyl arginine, Servier) reduces small AAA growth rate and (2) to evaluate blood pressure (BP)-independent effects of perindopril on small AAA growth and to compare the repeatability of measurement of internal and external aneurysm diameters.

DESIGN

A three-arm, multicentre, single-blind, randomised placebo-controlled trial.

SETTING

Fourteen hospitals in England.

PARTICIPANTS

Men or women aged ≥ 55 years with an AAA of 3.0-5.4 cm in diameter by internal or external measurement according to ultrasonography and who met the trial eligibility criteria.

INTERVENTIONS

Patients were randomised to receive 10 mg of perindopril arginine daily, 5 mg of the calcium channel blocker amlodipine daily or placebo daily.

MAIN OUTCOME MEASURES

The primary outcome was AAA diameter growth using external measurements in the longitudinal plane, which in-trial studies suggested was the preferred measure. Secondary outcome measures included AAA rupture, AAA repair, modelling of the time taken for the AAA to reach the threshold for intervention (5.5 cm) or referral for surgery, tolerance of study medication (measured by compliance, adverse events and quality of life) and a comparison of the repeatability of measures of internal and external AAA diameter. Patients were followed up every 3-6 months over 2 years.

RESULTS

In total, 227 patients were recruited and randomised into the three groups, which were generally well matched at baseline. Multilevel modelling was used to determine the maximum likelihood estimates for AAA diameter growth. No significant differences in the estimates of annual growth were apparent [1.68 (standard error 0.02) mm, 1.77 (0.02) mm and 1.81 (0.02) mm in the placebo, perindopril and amlodipine groups, respectively]. Similarly, no significant differences in the slopes of modelled growth over time were apparent between perindopril and placebo (p = 0.78) or between perindopril and amlodipine (p = 0.89). The results were essentially unaffected by adjustment for potential confounders. Compliance, measured by pill counts, was good throughout (> 80% at all visit time points). There were no significant in-trial safety concerns. Six patients withdrew because of adverse events attributed to the study medications (n = 2 perindopril, n = 4 amlodipine). No patients ruptured their AAA and 27 underwent elective surgery during the trial (n = 9 placebo, n = 10 perindopril, n = 8 amlodipine).

CONCLUSIONS

We were unable to demonstrate a significant impact of perindopril compared with placebo or amlodipine on small AAA growth over a 2-year period. Furthermore, there were no differences in the times to reach a diameter of 5.5 cm or undergo surgery among the three groups. Perindopril and amlodipine were well tolerated by this population. External AAA measurements were found to be more repeatable than internal measurements. The observed AAA growth measurement variability was greater than that expected pre trial. This, combined with slower than expected mean growth rates, resulted in our having limited power to detect small differences between growth rates and hence this adds uncertainty to the interpretation of the results. Several further analyses are planned including a multivariate analysis of determinants of AAA growth, an evaluation of the possible differential effect of perindopril on fast AAA growth and an investigation into the roles of central BP and BP variability on AAA growth.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN51383267.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 20, No. 59. See the NIHR Journals Library website for further project information. The NIHR Biomedical Research Centre based at Imperial College NHS Trust supported the trial. Servier provided perindopril at no charge.

Carotid Access for Endovascular Repair of Aortic Pathology: A Systematic Review

BACKGROUND

Endovascular repair is now preferred to open access for the management of aortic diseases. This is typically performed via the femoral artery; however, not all patients are eligible for this. This systematic review summarizes the current evidence for utilizing the carotid artery as an alternative access route.

METHODS

A systematic review was conducted as per the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines using 4 electronic databases.

RESULTS

The search found 11 case reports representing 12 patients eligible for analysis (mean age 64.5 years). This included 3 thoracic aneurysms, 3 abdominal aneurysms, 4 penetrating ulcers, 1 endoleak, and 1 pseudoaneurysm. An open procedure was contraindicated in 83% (10/12) due to the poor physiological fitness of the patient. In 75% (9/12) of cases, traditional endovascular access was contraindicated by severe iliac disease. The remainder were contraindicated because of an existing ligated aortic stump (1/12, 8.3%) or technical difficulty with graft deployment via the femoral artery (2/12, 16.7%). There was 1 death, with the 30-day mortality 8.3%. The same patient suffered the only spinal ischemia before death (8.3%). There were no cases of stroke (0%), with one case of transient ischemic attack (8.3%).

CONCLUSIONS

Although there is a relative paucity of literature, this study demonstrates when traditional endovascular access is impossible and an open procedure contraindicated, carotid artery access for endovascular repair of aortic pathology is a viable alternative with good 30-day survival and low rates of neurological sequelae.

Sex Chromosome Complement Defines Diffuse Versus Focal Angiotensin II-Induced Aortic Pathology

OBJECTIVE

Aortic pathologies exhibit sexual dimorphism, with aneurysms in both the thoracic and abdominal aorta (ie, abdominal aortic aneurysm [AAA]) exhibiting higher male prevalence. Women have lower prevalence of aneurysms, but when they occur, aneurysms progress rapidly. To define mechanisms for these sex differences, we determined the role of sex chromosome complement and testosterone on the location and progression of angiotensin II (AngII)-induced aortic pathologies.

APPROACH AND RESULTS

We used transgenic male mice expressing Sry (sex-determining region Y) on an autosome to create Ldlr (low-density lipoprotein receptor)-deficient male mice with an XY or XX sex chromosome complement. Transcriptional profiling was performed on abdominal aortas from XY or XX males, demonstrating 1746 genes influenced by sex chromosomes or sex hormones. Males (XY or XX) were either sham-operated or orchiectomized before AngII infusions. Diffuse aortic aneurysm pathology developed in XY AngII-infused males, whereas XX males developed focal AAAs. Castration reduced all AngII-induced aortic pathologies in XY and XX males. Thoracic aortas from AngII-infused XY males exhibited adventitial thickening that was not present in XX males. We infused male XY and XX mice with either saline or AngII and quantified mRNA abundance of key genes in both thoracic and abdominal aortas. Regional differences in mRNA abundance existed before AngII infusions, which were differentially influenced by AngII between genotypes. Prolonged AngII infusions resulted in aortic wall thickening of AAAs from XY males, whereas XX males had dilated focal AAAs.

CONCLUSIONS

An XY sex chromosome complement mediates diffuse aortic pathology, whereas an XX sex chromosome complement contributes to focal AngII-induced AAAs.

Psychosocial consequences in men taking part in a national screening program for abdominal aortic aneurysm

Screening for abdominal aortic aneurysm (AAA) has proven to reduce AAA-related mortality, but how the knowledge of having an untreated AAA affects health and daily life requires further clarification. The aim was to investigate the psychosocial consequences and sense of coherence (SOC) in 65-year-old men diagnosed with AAA and participating in a national screening program during a 6-month follow-up compared with men with no AAA. The single-center cohort study included 52 men with AAA and 118 men without AAA. A questionnaire including the Short Form 36 Health Survey, Hospital Anxiety and Depression Scale, SOC, questions concerning stress, and questions related to AAA were answered at baseline and after 6 months. Men with AAA reported more problems with physical functioning, pain, and general health than men with a normal aorta at baseline. After 6 months, men with AAA still reported more problems with physical functioning and stress in relation to disease than men with normal aortic diameter. No differences were observed between groups in SOC, anxiety, and depression. A significantly higher satisfaction with information from the physician and desire to learn about the AAA diagnosis was reported at baseline compared with that at follow-up. Having knowledge about the AAA diagnosis may moderately impact physical health and perceived stress, and in combination with the increased prevalence of other cardiovascular diseases, may lead to impaired perceived health for men diagnosed with AAA.

Natural History Of an Untreated Type 1 Endoleak: A Case Report

We present a case of giant abdominal aortic aneurysm greater than 17 cm complicated by an endoleak, demonstrating the natural history of an untreated Type 1 endoleak.

Precise treatment of aortic aneurysm by three-dimensional printing and simulation before endovascular intervention

In this study, three-dimensional printing (3Dp) models and simulation surgeries (SSs) were applied in two challenging aortic cases. The first was an abdominal aortic aneurysm with a complex neck, and the second was a thoracic aortic dissection aneurysm (TADA) with an angled arch. In order to avoid unpredictable obstacles and difficulties, we made optimal surgical plans by using 3D models and virtual simulations. Based on preoperative evaluation system, the surgical plans seemed more reasonable and time-saving.

The Association of Serum Thrombomodulin with Endothelial Injuring Factors in Abdominal Aortic Aneurysm

Background. The aim of the present study was to evaluate the concentration of serum thrombomodulin (sTM) in the AAA patients and to examine its correlation with various factors which may potentially participate in the endothelial injury. Materials and Methods. Forty-one patients with AAA were involved and divided into subgroups based on different criteria. Concentration of sTM was measured using enzyme-linked-immunosorbent assay (ELISA). The results were compared with those obtained in 30 healthy age- and sex-matched volunteers. Results. The higher concentration of sTM was observed in AAA patients compared with those in controls volunteers [2.37 (1.97–2.82) ng/mL versus 3.93 (2.43–9.20) ng/mL, P < 0.001]. An elevated sTM associated significantly with increased triglycerides (TAG) [P = 0.022], cholesterol [P = 0.029], hsCRP [P = 0.031], and advanced glycation end products (AGEs) [P = 0.033]. Conclusions. The elevation of serum sTM level suggests that endothelial damage occurs in AAA pathogenesis. The correlations observed indicate that lipids abnormalities, inflammation, and oxidative stress may be involved in this destructive process.

Female Mice With an XY Sex Chromosome Complement Develop Severe Angiotensin II-Induced Abdominal Aortic Aneurysms

BACKGROUND

Abdominal aortic aneurysms (AAAs) are a deadly pathology with strong sexual dimorphism. Similar to humans, female mice exhibit far lower incidences of angiotensin II-induced AAAs than males. In addition to sex hormones, the X and Y sex chromosomes, and their unique complements of genes, may contribute to sexually dimorphic AAA pathology. Here, we defined the effect of female (XX) versus male (XY) sex chromosome complement on angiotensin II-induced AAA formation and rupture in phenotypically female mice.

METHODS

Female low-density lipoprotein receptor (Ldlr) deficient mice with an XX or XY sex chromosome complement were infused with angiotensin II for 28 days to induce AAAs. Abdominal aortic lumen diameters were quantified by ultrasound, whereas AAA diameters were quantified at study end point. DNA microarrays were performed on abdominal aortas. To mimic males, female mice were administered a single dose of testosterone as neonates or as adults before angiotensin II infusions.

RESULTS

Female Ldlr^-/- deficient mice with an XX and XY sex chromosome complement had similar sex organ weights and low serum testosterone concentrations. Abdominal aortas from female XY mice selectively expressed Y chromosome genes, whereas genes known to escape X inactivation were higher in XX females. The majority of aortic gene differences in XY versus XX females fell within inflammatory pathways. AAA incidences doubled and aneurysms ruptured in XY females. AAAs from XY females exhibited inflammation, and plasma interleukin-1β concentrations were increased in XY females. Moreover, aortas from XY females had augmented matrix metalloproteinase activity and increased oxidative stress. Last, testosterone exposure applied chronically, or as a single bolus at postnatal day 1, markedly worsened AAA outcomes in XY in comparison with XX adult females.

CONCLUSIONS

An XY sex chromosome complement in phenotypic females profoundly influenced aortic gene expression profiles and promoted AAA severity. When XY females were exposed to testosterone, aneurysm rupture rates were striking. Mechanisms for augmented AAA severity in XY females include increased inflammation, augmented matrix metalloproteineases, and oxidative stress. Our results demonstrate that genes on the sex chromosomes regulate aortic vascular biology and contribute to sexual dimorphism of AAAs. Sex chromosome genes may serve as novel targets for sex-specific AAA therapeutics.

National trends for open and endovascular repair of aneurysms in Korea: 2004-2013

The introduction of endovascular aneurysm repair has led to a dramatic decline in open aneurysm repair. The aim of this report was to evaluate Korean national trends for the treatment of aneurysms. A serial, cross-sectional study of time trends of patients who underwent aneurysm repair between 2004 and 2013 was conducted. Data from the Health Insurance Review and Assessment Service were used to evaluate the trends of aneurysm repair in the Korean population and to analyze the trends of open and endovascular aneurysm repair among Medicare beneficiaries. A linear-by-linear association was performed to determine alterations in the rates at which these aneurysm repair techniques were performed. A total of 32,130 patients underwent aneurysm repair between 2004 and 2013. The proportion of patients who underwent open repair decreased from 94.0% in 2004 to 54.9% in 2013; whereas the proportion of patients who underwent endovascular repair increased from 6.0% in 2004 to 45.1% in 2013. During the study period, the number of patients undergoing endovascular repair of aortic aneurysms significantly increased from 82 to 1,396 (relative risk, 16.17; 95% confidence interval: 12.94-20.21). Endovascular repair of abdominal aortic aneurysms (AAAs)overtook open repair between 2010 and 2011. The frequency of open aneurysm repair increased 1.2-fold, with an overall downward trend. The prevalence of endovascular repair markedly increased 15.3-fold. These findings indicated that, in Korea, the endovascular repair of AAAs overtook open repair as the most common technique between 2010 and 2011.

Clinical utility of transthoracic echocardiography for screening abdominal aortic aneurysm: a prospective study in a Japanese population

BACKGROUND

The aim of the present study was to evaluate the clinical utility of transthoracic echocardiography (TTE) for screening abdominal aortic aneurysm (AAA) and to identify important TTE indices associated with AAA in a Japanese population.

METHODS

We prospectively studied 1912 patients who were referred for TTE. AAA was defined as ≥ 30 mm in size.

RESULTS

The abdominal aorta was visualized in 95.1% (1818/1912) by TTE. AAA was identified in 2.6% (47/1818). The aortic root size was significantly larger in patients with AAA than those without (36.0 ± 4.1 vs. 31.7 ± 4.2 mm, p < 0.001). The aortic root size had a fair correlation with abdominal aortic size (r = 0.31, p < 0.001). The aortic root size of ≥ 34 mm was predictive of AAA by receiver operating characteristic curve analysis (area under the curve = 0.78, p < 0.001). Multiple logistic regression analysis revealed that aortic root size (Hazard ratio 1.23, p < 0.001) and age (Hazard ratio 1.05, p = 0.013) were the independent predictors of AAA.

CONCLUSIONS

The feasibility of the abdominal aortic visualization during TTE was excellent. The aortic root size measured by TTE was the independent predictor of AAA. Screening for AAA during TTE appeared to be useful especially in the older patients with a large (≥34 mm) aortic root.

Improved trends in patient survival and decreased major complications after emergency ruptured abdominal aortic aneurysm repair

BACKGROUND

Improved trends in patient survival and decreased major complications after emergency ruptured abdominal aortic aneurysm (AAA) repair. Emergency AAA repair carries a high risk of morbidity and mortality. This study seeks to examine morbidity and mortality trends from the National Surgical Quality Improvement Program (NSQIP) database, and identify potential risk factors.

METHODS

All emergency AAA repairs were identified using the NSQIP database from 2005 to 2011. Univariate analysis (using the Student t, χ(2), and Fisher's exact tests) and multivariate logistic regression was performed to examine trends in mortality and morbidity.

RESULTS

Out of 2761 patients who underwent emergency AAA repair, 321 (11.6%) died within 24 hours of surgery. Of the remaining 2440 patients, 1133 (46.4%) experienced major complications and 459 (18.8%) died during the postoperative period. From 2005 to 2011, there was a significant decrease in patient mortality, particularly in patients who survived the perioperative period (P = .002). Total complications increased overall (P < .0001); however, major complications decreased from 58.7% in 2005 to 42.6% in 2011 (P < .0001) among patients who survived beyond 24 hours. The use of endovascular aortic repair (EVAR) increased over the study period (P < .0001). On multivariate analysis of patients who survived past the initial 24-hour period, advancing age (odds ratio [OR], 1.1; 95% confidence interval [CI], 1.0-1.1), chronic obstructive pulmonary disease (OR, 2.6; 95% CI, 1.7-4.1), dependent functional status (OR, 2.0; 95% CI, 1.2-3.2), and presence of a major complication (OR, 3.1; 95% CI, 2.0-5.0) were significantly associated with death, whereas presence of a senior resident (OR, 0.4; 95% CI, 0.3-0.6) or fellow (OR 0.3; 95% CI, 0.2-0.6) was inversely associated with death. EVAR was not associated with death, but was associated with 30-day complications (OR, 0.5; 95% CI, 0.3-0.6).

CONCLUSIONS

Patient survival has increased from 2005 to 2011 after emergency AAA repair, with a significant improvement particularly in patients who survive past the first 24 hours. EVAR was not associated with mortality, but was protective of 30-day complications. Although the total number of complications increased, the number of major complications decreased over the study period, suggesting that newer techniques and patient care protocols may be improving outcomes.

Isolated testicular pain mimicking ruptured abdominal aortic aneurysm in a nonagenarian

Ruptured abdominal aortic aneurysm commonly presents as acute abdominal or lower back pain and hemodynamic instability. We discuss the case of a 90-year-old patient who presented to the emergency unit with a 3-day history of left testicular pain. Ultrasound scan demonstrated and a computed tomography scan confirmed a 6 cm in diameter ruptured abdominal aortic aneurysm with enlargement and hematoma of the left psoas muscle causing the symptoms. This atypical presentation highlights the need for clinical vigilance and emergency physician–performed ultrasound scan in the older patients with seemingly benign testicular symptoms.

Advanced complicated diabetes mellitus is associated with a reduced risk of thoracic and abdominal aortic aneurysm rupture: a population-based cohort study

BACKGROUND

Studies have associated diabetes mellitus (DM) with the reduced risk of abdominal aortic aneurysm and thoracic aortic aneurysm and dissection. We used the national insurance data of Taiwan to examine these correlations for an Asian population. The association was also evaluated by DM severity.

METHODS

We identified 160,391 patients with type 2 DM diagnosed from 1998 to 2008 and 646,710 comparison subjects without DM, frequency matched by diagnosis date, sex and age (mainly the elderly). The DM severity was partitioned into advanced and uncomplicated status according to DM-related comorbidities.

RESULTS

By the end of 2010, the overall pooled incidence rate of thoracic aortic aneurysm and abdominal aortic aneurysm was 15% lower in the type 2 DM cohort than in non-DM cohort, with an adjusted hazard ratio of 0.64 [95% confidence interval (CI) 0.56-0.74] in the multivariable Cox model. Patients with advanced type 2 DM were significantly associated with reduced thoracic aortic aneurysm rupture and abdominal aortic aneurysm without rupture, with adjusted hazard ratios of 0.50 (95% CI 0.35-0.71) and 0.53 (95% CI 0.40-0.69), respectively. Uncomplicated type 2 DM was also associated with reduced abdominal aortic aneurysm without rapture (aHR = 0.58, 95% CI 0.45-0.74).

CONCLUSIONS

Our results demonstrate that patients with diabetes in this Asian population have reduced prevalence of thoracic and abdominal aortic aneurysms. The observed paradoxical inverse relationship between severity of DM and aortic aneurysms is clear. Further research is required to investigate the underlying mechanisms for the reduced risk of aortic aneurysms associated with diabetes.

Ruptured abdominal aortic aneurysms: decreasing incidence may reduce the impact of a Scottish screening programme

Objectives

The aim of this study was to determine whether there has been a change in annual ruptured abdominal aortic aneurysm admissions and elective abdominal aortic aneurysm repairs in a tertiary vascular surgery department.

Methods

All patients admitted with ruptured abdominal aortic aneurysm from 1987 to 2009 and all undergoing elective abdominal aortic aneurysm repair from 1995 to 2009 were identified from the local surgical audit database. Annual ruptured abdominal aortic aneurysm admissions were calculated and compared in the first and second halves of the study period.

Results

During a 23-year period, 888 patients (male 728, female 158, gender was not documented for two patients) were identified with a ruptured abdominal aortic aneurysm. The annual number of admissions remained relatively constant from 1987 to 1997, with a mean of 44 (95% CI 39.91–48.09). There was a significant decrease to a mean of 33.67 per annum (95% CI 28.53–38.8) in the period 1998–2009, p = 0.006. The mean mortality was 39.8% and showed no significant decrease. There was no increase in the number of elective abdominal aortic aneurysm repairs during the study period.

Conclusions

This study suggests that the incidence of ruptured abdominal aortic aneurysms is decreasing, mirroring the trend seen in other cardiovascular disease. As such, further analysis as to the cost-effectiveness of a Scottish screening programme is merited.

Discovery of Cathepsin S Inhibitor LY3000328 for the Treatment of Abdominal Aortic Aneurysm

Cathepsin S (Cat S) plays an important role in many pathological conditions, including abdominal aortic aneurysm (AAA). Inhibition of Cat S may provide a new treatment for AAA. To date, several classes of Cat S inhibitors have been reported, many of which form covalent interactions with the active site Cys25. Herein, we report the discovery of a novel series of noncovalent inhibitors of Cat S through a medium-throughput focused cassette screen and the optimization of the resulting hits. Structure-based optimization efforts led to Cat S inhibitors such as 5 and 9 with greatly improved potency and drug disposition properties. This series of compounds binds to the S2 and S3 subsites without interacting with the active site Cys25. On the basis of in vitro potency, selectivity, and efficacy in a CaCl2-induced AAA in vivo model, 5 (LY3000328) was selected for clinical development.

Management of Aneurysmal Disease of the Aorta

Aneurysm of the aorta is largely a disease of the elderly. The incidence/prevalence of the disease has steadily increased in recent times, mainly because of the increase in awareness among patients/physicians and better imaging modalities. Early diagnosis and treatment of this disease holds the key to success and plays a part in prevention of catastrophic complications. With advancements in endovascular and surgical innovations, repair of aneurysmal disease has made significant progress, translating into better survival and long-term benefits. However, with significant morbidity and mortality associated with this disease, there is still a need for further research.

Functional and molecular imaging techniques in aortic aneurysm disease

PURPOSE OF REVIEW

Functional and molecular aortic imaging has shown great promise for evaluation of aortic disease, and may soon augment conventional assessment of aortic dimensions for the clinical management of patients.

RECENT FINDINGS

A range of imaging techniques is available for evaluation of patients with aortic disease. Magnetic resonance blood flow imaging can identify atherosclerosis prone aortic regions and may be useful for predicting aneurysm growth. Computational modeling can demonstrate significant differences in wall stress between abdominal aortic aneurysms of similar size and may better predict rupture than diameter alone. Metabolic imaging with fluorodeoxyglucose-PET [(FDG)-PET] can identify focal aortic wall inflammation that may portend rapid progression of disease. Molecular imaging with probes that target collagen and elastin can directly exhibit changes in the vessel wall associated with disease.

SUMMARY

The complexity of aortic disease is more fully revealed with new functional imaging techniques than with conventional anatomic analysis alone. This may better inform surveillance imaging regimens, medical management and decisions regarding early intervention for aortic disease.

"Off-the-shelf" devices for complex aortic aneurysm repair

BACKGROUND

Fenestrated devices currently require a 3- to 4-week manufacturing period before implantation; as such, there have been efforts to develop "off-the-shelf" (OTS) devices to reduce the time before definitive treatment can be accomplished. We examined all patients treated for complex aortic problems at our institution during the past 12 months to evaluate the suitability and early outcomes of the OTS devices vs commercially available endovascular options.

METHODS

Between July 2012 and September 2013, patients undergoing aortic aneurysm repair were extracted from a prospectively managed aortic database. Two OTS devices, the Cook (Bloomington, Ind) p-Branch and the Endologix (Irvine, Calif) Ventana device, were being evaluated through clinical trials during this time frame. The custom Cook Zenith fenestrated endovascular (ZFEN) device was also available and approved by the U.S. Food and Drug Administration (FDA) during the study period.

RESULTS

Of 224 aortic aneurysms treated at our institution during this period, there were a total of 85 patients with type IV thoracoabdominal aneurysms including juxtarenal aneurysms. Only 23 patients (27%) met anatomic criteria for OTS devices, with 16 patients having these investigational devices implanted. The major exclusion criterion for the p-Branch device was renal axial or circumferential position; the limiting factor for Ventana was infrasuperior mesenteric artery neck length restriction. Five of the patients who would have fit criteria for an OTS device had an FDA-approved (ZFEN) device implanted instead, and two patients opted for open repair as a result of follow-up requirements. An additional 25 patients received custom-designed (ZFEN) devices (n = 30; 35%), whereas 37 (44%) others did not meet criteria for any available endovascular device and were repaired with alternative management strategies. The mean age and maximal aortic diameter of the two cohorts (OTS and ZFEN) were 71.8 years and 72.7 years (P = NS) and 61.3 mm and 58.5 mm (P = NS), respectively. Technical success was 100%, with an overall 30-day mortality of 2.1% (n = 1, ZFEN). Major complications occurred in eight patients (17%; two OTS, six ZFEN).

CONCLUSIONS

Whereas OTS device strategies will reduce the waiting times for patients with complex aortic aneurysmal disease, a significant number will still require custom-made device repair until additional device designs become available. Early experience with OTS devices does not demonstrate any significant renal risks; however, the treatment numbers are low and should be interpreted with caution until larger confirmatory studies are published. Further studies comparing the outcomes of these techniques are required to establish the best approach to handle endovascular repair of complex aortic aneurysm.

Prevalence and trends of the abdominal aortic aneurysms epidemic in general population--a meta-analysis

OBJECTIVE

To conduct a meta-analysis assessing the prevalence and trends of the abdominal aortic aneurysms (AAA) epidemic in general population.

METHOD

Studies that reported prevalence rates of AAA from the general population were identified through MEDLINE, EMBASE, Web of Science, and reference lists for the period between 1988 and 2013. Studies were included if they reported prevalence rates of AAA in general population from the community. In stratified analyses possible sources of bias, including areas difference, age, gender and diameter of aneurysms were examined. Publication bias was assessed with Egger's test method.

RESULTS

56 studies were identified. The overall pooled prevalence of AAA was 4.8% (4.3%, 5.3%). Stratified analyses showed the following results, areas difference: America 2.2% (2.2%, 2.2%), Europe 2.5% (2.4%, 2.5%), Australia 6.7% (6.5%, 7.0%), Asia 0.5% (0.3%, 0.7%); gender difference: male 6.0% (5.3%, 6.7%), female 1.6% (1.2%, 1.9%); age difference: 55-64years 1.3% (1.2%, 1.5%), 65-74 years 2.8% (2.7%, 2.9%), 75-84 years1.2%(1.1%, 1.3%), ≥85years0.6% (0.4%, 0.7%); aortic diameters difference: 30-39 mm, 3.3% (2.8%, 3.9%), 40-49 mm,0.7% (0.4%,1.0%), ≥50 mm, 0.4% (0.3%, 0.5%). The prevalence of AAA has decreased in Europe from 1988 to 2013. Hypertension, smoking, coronary artery disease, dyslipidemia, respiratory disease, cerebrovascular disease, claudication and renal insufficiency were risk factors for AAA in Europe.

CONCLUSION

AAA is common in general population. The prevalence of AAA is higher in Australia than America and Europe. The pooled prevalence in western countries is higher than the Asia. Future research requires a larger database on the epidemiology of AAA in general population.

Reference diameters of the abdominal aorta and iliac arteries in the Korean population

PURPOSE

It is important to know the normal diameter of artery throughout the body so that clinicians are able to determine when an artery becomes aneurysmal. However, there are no previous studies on the normal diameter of arteries in the general Korean population. The purpose of this article is to determine the normal reference diameters of the abdominal aorta and iliac arteries in the Korean population.

MATERIALS AND METHODS

We recruited the study population from three cities in Korea for the abdominal aortic aneurysm (AAA) screening. We measured the diameter of the aorta and iliac arteries. We analyzed the reference diameter of the population without AAA. The results were analyzed by Student's t-test and ANOVA on SPSS version 19. A p value <0.05 was considered to be statistically significant.

RESULTS

One thousand two hundred and twenty-nine people were enrolled. 478 men and 751 women, with a mean age of 63.9 ± 10.1 years (range 50 to 91) were examined. Eleven out of 1229 (0.89%) were diagnosed with AAA. In the population of 1218 people without AAA, the mean diameters (cm) of male/female were 2.20/2.11 (p<0.001) at suprarenal, 2.04/1.90 (p<0.001) at renal, 1.90/1.79 (p<0.001) at infrarenal, 1.22/1.17 (p<0.001) at right iliac and 1.47/1.15 (p=0.097) at the left iliac, respectively. There was a significantly larger diameter in the male population. The diameter of each level increased with age.

CONCLUSION

The normal reference diameter of the infrarenal abdominal aorta in the Korean population is 1.9 cm in males and 1.79 cm in females. The diameter of the abdominal aorta increases with age.

Changes in abdominal aortic aneurysm rupture and short-term mortality, 1995-2008: a retrospective observational study

OBJECTIVE

To examine the modern epidemiology of abdominal aortic aneurysm (AAA) rupture and short-term AAA-related mortality after the introduction of endovascular aneurysm repair (EVAR).

BACKGROUND

Previous epidemiologic studies have demonstrated stable rates of AAA repair, repair mortality, and AAA rupture. Recently, EVAR has been introduced as a less invasive treatment method, and its use has expanded to more than 75% of elective AAA repairs.

METHODS

We identified Medicare beneficiaries undergoing AAA repair and those hospitalized with a ruptured AAA during the period 1995 to 2008 and calculated standardized annual rates of AAA-related deaths due to either elective repair or rupture.

RESULTS

A total of 338,278 patients underwent intact AAA repair during the study period. There were 69,653 patients with AAA rupture, of whom 47,524 underwent repair. Intact repair rates increased substantially in those older than 80 years (57.7-92.3 per 100,000, P < 0.001) but decreased in those 65 to 74 years old (81.8-68.9, P < 0.001). A decline in ruptures with and without repair was seen in all age groups. By 2008, 77% of all intact repairs and 31% of all rupture repairs were performed with EVAR (P < 0.001). Operative mortality declined during the study period for both intact (4.9%-2.4%, P < 0.001) and ruptured (44.1%-36.3%, P < 0.001) AAA repair. Short-term AAA-related deaths decreased by more than half (26.1-12.1 per 100,000, P < 0.001), with the greatest decline occurring in those older than 80 years (53.7-27.3, P < 0.001).

CONCLUSIONS

A recent decline in AAA rupture and short-term AAA-related mortality is demonstrated and likely related in part to the introduction and expansion of EVAR. This is due to decreased deaths from ruptures (with and without repair) and decreased mortality with intact repairs, particularly in patients older than 80 years.

Ruptured abdominal aortic aneurysm: the state of play

BACKGROUND

Ruptured abdominal aortic aneurysm (rAAA) remains a challenging problem: 2,410 cases were treated in Germany in 2010. Ruptured abdominal aortic aneurysm should be suspected in patients over age 50 who complain of pain in the abdomen or back and in whom examination reveals a pulsatile abdominal mass. The incidence of hospitalization for rAAA is 12 per 100,000 persons over age 65 per year (statistics for Germany, 2010), and rAAA carries an overall mortality of 80%.

METHODS

The current state of knowledge of rAAA was surveyed in a selective review of pertinent literature retrieved by an electronic search in the PubMed, Web of Science, and Cochrane Library databases with the keywords "abdominal aortic aneurysm," "ruptured," "open repair," and "endovascular." Publications in English or German up to and including March 2012 were considered, among them the Clinical Practice Guidelines of the European Society for Vascular Surgery (1).

RESULTS AND CONCLUSIONS

Recent reports show that the treatment of rAAA is still fraught with high mortality and high perioperative morbidity. Improvement is needed. It would be advisable for the care of rAAA to be centralized in specialized vascular centers implementing defined treatment pathways. Systematic screening, too, would be beneficial. An increasing number of reports suggest that endovascular treatment with stent prostheses improves outcomes; more definitive evidence on this matter will come from prospective, randomized trials that are now in progress.

Macrophage-derived angiopoietin-like protein 2 accelerates development of abdominal aortic aneurysm

OBJECTIVE

Recently, we reported that angiopoietin-like protein 2 (Angptl2) functions in various chronic inflammatory diseases. In the present study, we asked whether Angptl2 and its associated chronic inflammation contribute to abdominal aortic aneurysm (AAA).

METHODS AND RESULTS

Immunohistochemistry revealed that Angptl2 is abundantly expressed in infiltrating macrophages within the vessel wall of patients with AAA and in a CaCl(2)-induced AAA mouse model. When Angptl2-deficient mice were used in the mouse model, they showed decreased AAA development compared with wild-type mice, as evidenced by reduction in aneurysmal size, less severe destruction of vessel structure, and lower expression of proinflammatory cytokines and matrix metalloproteinase-9. However, no difference in the number of infiltrating macrophages within the aortic aneurysmal vessel wall was observed between genotypes. AAA development was also significantly suppressed in wild-type mice that underwent Angptl2-deficient bone marrow transplantation. Expression levels of proinflammatory cytokines and metalloproteinase-9 in Angptl2-deficient macrophages were significantly decreased, and those decreases were rescued by treatment of Angptl2 deficient macrophages with exogenous Angptl2.

CONCLUSIONS

Macrophage-derived Angptl2 contributes to AAA development by inducing inflammation and degradation of extracellular matrix in the vessel wall, suggesting that targeting the Angptl2-induced inflammatory axis in macrophages could represent a new strategy for AAA therapy.

Changing Epidemiology of Abdominal Aortic Aneurysms in England and Wales

Background—

Recent studies from Australia, New Zealand, and Sweden have reported declines in abdominal aortic aneurysm (AAA) incidence, prevalence, and mortality. This finding may have important implications for screening programs. This study determined trends in AAA incidence and mortality in England and Wales.

Methods and Results—

Cause-specific mortality data for England and Wales were obtained from UK Office for National Statistics, and hospital admissions and procedures data for England were obtained from Hospital Episode Statistics from 2001 to 2009. Poisson regression models were constructed to estimate the relative change over time. Age-standardized rates for AAA mortality in England and Wales fell significantly by 35.7% from 2001 to 2009, which was largely due to a 35.3% drop in age-standardized ruptured AAA deaths. During the same period, ruptured AAA admissions and emergency AAA repairs in England declined by 29.3% and 35.5%, respectively. In contrast, nonruptured AAA admissions remained static, and nonemergency AAA repairs increased by 17.2%. The average ages for hospital admissions for nonruptured AAAs and ruptured AAAs increased by 0.19 years of age per annum ( P <0.001) and 0.09 years of age per annum ( P <0.001), respectively. Nonruptured AAA admissions increased by 21.4% in age band 75 years or more but declined by 11.7% in ages <75 years.

Conclusions—

AAA mortality, ruptured AAA admission, and emergency AAA repair have declined in England and Wales. However, nonruptured AAA admission has remained steady, with an increasing rate in older population offsetting a decreasing rate in younger population. This suggests a shift in AAA presentation to the older population. Present screening strategies may need reassessment to include consideration for increasing the age at which to screen men for AAAs.

Screening for abdominal aortic aneurysms

Ruptured AAA ranks as the 15th leading cause of death overall in the United States, and the 10th leading cause of death in men older than 55 years. Early identification of AAA can save livesand diminish cost. Screening programs havebeen implemented and studied in other countries and have shown a measurable and significant reduction in overall rate of aneurysm-related death. Currently, one-time screening of a small number of ever-smoking men when they turn 65 screening is not widely used in the United States and Medicare, at best, provides one-time screening of a small number of ever-smoking men when they turn 65 years old. Because more than 30,000 individuals in the United States die each year of ruptured AAA, a great deal of progress must be made to eradicate rupture from aneurysmal disease. A more comprehensive system of screening is required and this should be uniformly applied to the U.S. population. It is hoped that scoring systems such as the one outlined in this article, if widely adopted, can greatly enhance screening for aneurysmal disease and prevent the high mortality that stems from this serious vascular disease.

Abdominal aortic aneurysm is associated with a variant in low-density lipoprotein receptor-related protein 1

Abdominal aortic aneurysm (AAA) is a common cause of morbidity and mortality and has a significant heritability. We carried out a genome-wide association discovery study of 1866 patients with AAA and 5435 controls and replication of promising signals (lead SNP with a p value < 1 × 10(-5)) in 2871 additional cases and 32,687 controls and performed further follow-up in 1491 AAA and 11,060 controls. In the discovery study, nine loci demonstrated association with AAA (p < 1 × 10(-5)). In the replication sample, the lead SNP at one of these loci, rs1466535, located within intron 1 of low-density-lipoprotein receptor-related protein 1 (LRP1) demonstrated significant association (p = 0.0042). We confirmed the association of rs1466535 and AAA in our follow-up study (p = 0.035). In a combined analysis (6228 AAA and 49182 controls), rs1466535 had a consistent effect size and direction in all sample sets (combined p = 4.52 × 10(-10), odds ratio 1.15 [1.10-1.21]). No associations were seen for either rs1466535 or the 12q13.3 locus in independent association studies of coronary artery disease, blood pressure, diabetes, or hyperlipidaemia, suggesting that this locus is specific to AAA. Gene-expression studies demonstrated a trend toward increased LRP1 expression for the rs1466535 CC genotype in arterial tissues; there was a significant (p = 0.029) 1.19-fold (1.04-1.36) increase in LRP1 expression in CC homozygotes compared to TT homozygotes in aortic adventitia. Functional studies demonstrated that rs1466535 might alter a SREBP-1 binding site and influence enhancer activity at the locus. In conclusion, this study has identified a biologically plausible genetic variant associated specifically with AAA, and we suggest that this variant has a possible functional role in LRP1 expression.

Trends in incidence and mortality from abdominal aortic aneurysm in New Zealand

BACKGROUND

This study examined trends in abdominal aortic aneurysm (AAA) incidence and mortality in New Zealand (NZ) and compared these with mortality rates from England and Wales.

METHODS

Cause-specific death data were obtained from the NZ Ministry of Health, UK Office for National Statistics and National Archives (for England and Wales). The NZ National Minimum Data Set provided hospital discharge data from July 1994 to June 2009.

RESULTS

In 2005-2007 the age-standardized AAA mortality rate for men was 33·3 per cent less in NZ than in England and Wales (5·21 versus 7·81 per 100 000), whereas for women it was 9·8 per cent less (2·12 versus 2·35 per 100 000). Standardized mortality rates in NZ fell by 53·0 per cent for men and 34·1 per cent for women from 1991 to 2007. Between 1991-1992 and 2005-2007 the probability of a 65-year-old dying from an AAA fell by 28·2 per cent (from 1·872 to 1·344 per cent) in men, and by 6·3 per cent (from 0·837 to 0·784 per cent) in women. New AAA admission and hospital death rates in NZ peaked in 1999 for men, and in 2001 for women, and have since declined sharply. Hospital mortality ratios have also fallen, except for women with a ruptured aneurysm.

CONCLUSION

The burden of AAA disease has been falling since at least 1991 in NZ, and since 1995 in England and Wales. Although survival appears to be improving, most of the reduction is due to lower disease incidence.

Prevalence of abdominal aortic aneurysm in Chinese patients with severe coronary artery disease

BACKGROUND

The Asian population is believed to have lower incidence of abdominal aortic aneurysm (AAA), and hence, the benefit of screening is uncertain. The size of native aorta in Asians, which shall affect the definition of AAA, has also never been reported. Our study investigated the prevalence of AAA and the infra-renal aortic diameter (AD) in Chinese patients with severe coronary artery disease.

METHODS

This is a prospective observational study of infra-renal aortic size for patients who had coronary artery bypass surgery by ultrasound. The patients' demographics, important co-morbidities and maximum AD were recorded.

RESULTS

The study included 624 consecutive Chinese patients (mean age = 63.2 years). The mean maximum infra-renal AD was 17.5 mm for men and 14.8 mm for women. The presence of AAA was defined as maximum AD greater than 30 mm. The result was also compared with an alternate definition that defines AAA as maximum AD of greater than 1.5 times of the group's mean. Eleven patients had an AD greater than 30 mm, and the prevalence of AAA was only 1.8%. With AAA defined as maximum AD of 1.5 times greater than the group's mean, 19 patients had AAA. The prevalence of AAA in this high-risk group would become 3% overall.

CONCLUSION

The prevalence of AAA in Chinese patients was low, and the result did not support routine screening. The smaller mean infra-renal AD in Chinese merits validation by large-scale study and consideration when deciding threshold for small AAA repair in our locality.