Abdominal aortic aneurysm

Integrated particle image velocimetry and fluid-structure interaction analysis for patient-specific abdominal aortic aneurysm studies

BACKGROUND

Understanding the hemodynamics of an abdominal aortic aneurysm (AAA) is crucial for risk assessment and treatment planning. This study introduces a low-cost, patient-specific in vitro AAA model to investigate hemodynamics using particle image velocimetry (PIV) and flow-simulating circuit, validated through fluid-structure interaction (FSI) simulations.

METHODS

In this study, 3D printing was employed to manufacture a flexible patient-specific AAA phantom using a lost-core casting technique. A pulsatile flow circuit was constructed using off-the-shelf components. A particle image velocimetry (PIV) setup was built using an affordable laser source and global shutter camera, and finally, the flow field inside the AAA was analyzed using open-source software. Fluid-structure interaction (FSI) simulations were performed to enhance our understanding of the flow field, and the results were validated by PIV analysis. Both steady-state and transient flow conditions were investigated.

RESULTS

Our experimental setup replicated physiological conditions, analyzing arterial wall deformations and flow characteristics within the aneurysm. Under constant flow, peak wall deformations and flow velocities showed deviations within - 12% to + 27% and - 7% to + 5%, respectively, compared to FSI simulations. Pulsatile flow conditions further demonstrated a strong correlation (Pearson coefficient 0.85) in flow velocities and vectors throughout the cardiac cycle. Transient phenomena, particularly the formation and progression of vortex structures during systole, were consistently depicted between experimental and numerical models.

CONCLUSIONS

By bridging high-fidelity experimental observations with comprehensive computational analyses, this study underscores the potential of integrated methodologies in enhancing our understanding of AAA pathophysiology. The convergence of realistic AAA phantoms, precise PIV measurements at affordable cost point, and validated FSI models heralds a new paradigm in vascular research, with significant implications for personalized medicine and bioengineering innovations.

A two-scale numerical study on the mechanobiology of abdominal aortic aneurysms

Abdominal aortic aneurysms (AAAs) are a serious condition whose pathophysiology is related to phenomena occurring at different length scales. To gain a better understanding of the disease, this work presents a multi-scale computational study that correlates AAA progression with microstructural and mechanical alterations in the tissue. Macro-scale geometries of a healthy aorta and idealized aneurysms with increasing diameter are developed on the basis of existing experimental data and subjected to physiological boundary conditions. Subsequently, microscopic representative volume elements of the abluminal side of each macro-model are employed to analyse the local kinematics at the cellular scale. The results suggest that the formation of the aneurysm disrupts the micromechanics of healthy tissue, which could trigger collagen growth and remodelling by mechanosensing cells. The resulting changes to the macro-mechanics and microstructure of the tissue seem to establish a new homeostatic state at the cellular scale, at least for the diameter range investigated.

Dynamic Loading-A New Marker for Abdominal Aneurysm Growth?

The growing possibilities of non-invasive heart rate and blood pressure measurement with mobile devices allow vital data to be continuously collected and used to assess patients' health status. When it comes to the risk assessment of abdominal aortic aneurysms (AAA), the continuous tracking of blood pressure and heart rate could enable a more patient-specific approach. The use of a load function and an energy function, with continuous blood pressure, heart rate, and aneurysm stiffness as input parameters, can quantify dynamic load on AAA. We hypothesise that these load functions correlate with aneurysm growth and outline a possible study procedure in which the hypothesis could be tested for validity. Subsequently, uncertainty quantification of input quantities and derived quantities is performed.

Human abdominal aortic aneurysm (AAA): Evidence for an autoimmune antigen-driven disease

Abdominal aortic aneurism (AAA) is a complex immunological disease with a strong genetic component, and one of the ten leading causes of death of individuals 55-74 years old worldwide. Strong evidence has been accumulated suggesting that AAA is an autoimmune specific antigen-driven disease. Mononuclear cells infiltrating AAA lesions comprised of T and B lymphocytes and other cells expressing early-, intermediate- and late-activation antigens, and the presence of antigen-presenting cells have been documented, demonstrating an ongoing immune response. The three components of the trimolecular complex, T-cell receptor (TCR)/peptide (antigen)/HLA have been identified in AAA, and specifically: (i) clonal expansions of T-cell clones in AAA lesions; (ii) the association of AAA with particular HLA Class I and Class II; and (iii) self or nonself putative AAA-associated antigens. IgG autoantibodies recognizing proteins present in normal aortic tissue have been reported in patients with AAA. Molecular mimicry, defined as the sharing of antigenic epitopes between microorganisms (bacteria, viruses) and self antigens, maybe is responsible for T-cell responses and antibody production in AAA. Also, the frequency and the suppressor activity of CD4 + CD25 + FOXP3+ Tregs and the expression of FOXP3 transcripts and protein have been reported to be significantly impaired in AAA patients vs normal donors.

Multiscale simulations suggest a protective role of neo-adventitia in abdominal aortic aneurysms

Abdominal aortic aneurysms (AAAs) are a dangerous cardiovascular disease, the pathogenesis of which is not yet fully understood. In the present work a recent mechanopathological theory, which correlates AAA progression with microstructural and mechanical alterations in the tissue, is investigated using multiscale models. The goal is to combine these changes, within the framework of mechanobiology, with possible mechanical cues that are sensed by vascular cells along the AAA pathogenesis. Particular attention is paid to the formation of a 'neo-adventitia' on the abluminal side of the aortic wall, which is characterized by a highly random (isotropic) distribution of collagen fibers. Macro- and micro-scale results suggest that the formation of an AAA, as expected, perturbs the micromechanical state of the aortic tissue and triggers a growth and remodeling (G&R) reaction by mechanosensing cells such as fibroblasts. This G&R then leads to the formation of a thick neo-adventitia that appears to bring the micromechanical state of the tissue closer to the original homeostatic level. In this context, this new layer could act like a protective sheath, similar to the tunica adventitia in healthy aortas. This potential 'attempt at healing' by vascular cells would have important implications on the stability of the AAA wall and thus on the risk of rupture. STATEMENT OF SIGNIFICANCE: Current clinical criteria for risk assessment in AAAs are still empirical, as the causes and mechanisms of the disease are not yet fully understood. The strength of the arterial tissue is closely related to its microstructure, which in turn is remodeled by mechanosensing cells in the course of the disease. In this study, multiscale simulations show a possible connection between mechanical cues at the microscopic level and collagen G&R in AAA tissue. It should be emphasized that these micromechanical cues cannot be visualized in vivo. Therefore, the results presented here will help to advance our current understanding of the disease and motivate future experimental studies, with important implications for AAA risk assessment.

CCL7 contributes to angiotensin II-induced abdominal aortic aneurysm by promoting macrophage infiltration and pro-inflammatory phenotype

Chemokine C‐C motif ligand 7 (CCL7), a member of CC chemokine subfamily, plays pivotal roles in numerous inflammatory diseases. Hyper‐activation of inflammation is an important characteristic of abdominal aortic aneurysm (AAA). Therefore, in the present study, we aimed to determine the effect of CCL7 on AAA formation. CCL7 abundance in aortic tissue and macrophage infiltration were both increased in angiotensin II (Ang II)‐induced AAA mice. Ex vivo, CCL7 promoted macrophage polarization towards M1 phenotype. This effect was reversed by the blockage of CCR1, a receptor of CCL7. CCL7 up‐regulated JAK2/STAT1 protein level in macrophage, and CCL7‐induced M1 activation was suppressed by JAK2/STAT1 pathway inhibition. To verify the effect of CCL7 on AAA in vivo, either CCL7‐neutralizing antibody (CCL7‐nAb) or vehicles were intraperitoneally injected 24 hours prior to Ang II infusion and subsequently every three days for 4 weeks. CCL7‐nAb administration significantly attenuated Ang II‐induced luminal and external dilation as well as pathological remodelling. Immunostaining showed that CCL7‐nAb administration significantly decreased aneurysmal macrophage infiltration. In conclusion, CCL7 contributed to Ang II‐induced AAA by promoting M1 phenotype of macrophage through CCR1/JAK2/STAT1 signalling pathway.

Examining the impact of psychological distress on short-term postoperative outcomes after elective endovascular aneurysm repair (EVAR)

PURPOSE

Preoperative psychological factors have an impact on postoperative outcomes and there is a paucity of research in vascular surgery. The objective of this study was to examine the impact of preoperative psychological factors on short-term postoperative outcomes in an infrarenal endovascular aneurysm repair (EVAR) cohort.

METHODS

A prospective, multi-centre observational study was conducted across three vascular units in England. English-speaking participants who were older than 18 years, able to provide informed consent and awaiting an elective standard infrarenal EVAR were eligible for the study. A total of 46 patients undergoing elective infrarenal AAA repair were assessed preoperatively with the State Trait Anxiety Inventory (STAI), Beck's Depression Inventory (BDI-II) and Life Orientation Test-Revised (LOT-R). Data on five short-term postoperative outcomes was collected and analysed using Spearman's rank correlations.

RESULTS

Higher preoperative anxiety levels (ρ = 0.38, p = 0.01), and depression scores (ρ = 0.36, p = 0.02) were moderately correlated with an increased length of postoperative critical care stay. Higher levels of preoperative depression were moderately correlated with greater postoperative opioid analgesia use (ρ = 0.34, p = 0.02). No correlation was witnessed between optimism scores and postoperative outcomes. No correlation was witnessed with respect to total length of stay, number of complications, or time to mobilisation.

CONCLUSIONS

There is a potential link between preoperative psychological well-being and short-term postoperative outcomes in an EVAR cohort. Further work is necessary to validate this link and examine the role of preoperative interventions in optimising the psychological well-being of patients undergoing EVAR.

Numerical study on the effect of stent shape on suture forces in stent-grafts

Second-generation stent-grafts (SGs) have addressed many of the mechanical problems reported for first-generation endoprostheses, such as graft tear and stent rupture; however, suture wear and detachment due to pulsatile fatigue remains an issue. Numerical studies on the mechanical behavior of these endoprostheses usually model the attachment between stents and graft as a continuous ''tie'' constraint, which does not provide information on the mechanical loads acting on individual sutures. This paper presents a suitable approach for Finite Element (FE) simulations of SGs which allows for a qualitative evaluation of the loads acting on sutures. Attachment between stents and graft is modeled as rigid beams at discrete locations of the endoprostheses, and the reaction forces on the beams are analyzed. This modeling strategy is employed for four different SG models (two Z-stented commercial models and two circular-stented models) subjected to a severe 180° U-bend, followed by intraluminal pressurization. Results show that, for all models, the majority of sutures is experiencing fluctuating forces within a cardiac cycle (between 80 and 120 mmHg), which points to pulsatile fatigue as potential failure mode. In addition, the highest loads are concentrated in kinks and, for Z-stented models, at the apexes of stents. Moreover, suture loads for circular-stented models are lower than for Z-stented models, indicating better resistance to suture detachment. All these observations are in line with experimental results published in the literature, and, therefore, the procedure herein proposed may serve as a valuable tool in the development of new SG models with better suture resistance to pulsatile wear and fatigue.

The TAGA Study: A Study of Factors Determining Aortic Diameter in Families at High Risk of Abdominal Aortic Aneurysm Reveal Two New Candidate Genes

A variety of disorders are known to be related with aortic geometry, among them abdominal aortic aneurysm (AAA). This work aims to present the main determinants of abdominal aortic diameter in a new cohort of families at high risk of AAA. The Triple-A Genomic Analysis (TAGA) study comprises 407 individuals related in 12 families. Each family was collected through a proband with AAA. We calculated heritability and genetic correlations between abdominal aortic diameter and clinical parameters. A genome-wide linkage scan was performed based on 4.6 million variants. A predictive model was calculated with conditional forest. Heritability of the abdominal aortic diameter was 34%. Old age, male sex, higher height, weight, creatinine levels in serum, and better lung capacity were the best predictors of aortic diameter. Linkage analyses suggested the implication of Epidermal Growth Factor Receptor (EGFR) and Betacellulin (BTC) genes with aortic diameter. This is the first study to evaluate genetic components of variation of the aortic diameter in a population of AAA high-risk individuals. These results reveal EGFR, a gene that had been previously implicated in AAA, as a determinant of aortic diameter variation in healthy genetically enriched individuals, and might indicate that a common genetic background could determine the diameter of the aorta and future risk of AAA.

Clonally expanded alpha-chain T-cell receptor (TCR) transcripts are present in aneurysmal lesions of patients with Abdominal Aortic Aneurysm (AAA)

Abdominal aortic aneurysm (AAA) is a life-threatening immunological disease responsible for 1 to 2% of all deaths in 65 year old or older individuals. Although mononuclear cell infiltrates have been demonstrated in AAA lesions and autoimmunity may be responsible for the initiation and account for the propagation of the disease, the information available about the pathogenesis of AAA is limited. To examine whether AAA lesions from patients with AAA contain clonally expanded α-chain TCR transcripts, we amplified by the non-palindromic adaptor-PCR (NPA-PCR)/Vα-specific PCR and/or the Vα-specific PCR these α-chain TCR transcripts. The amplified transcripts were cloned and sequenced. Substantial proportions of identical α-chain TCR transcripts were identified in AAA lesions of 4 of 5 patients, demonstrating that clonally expanded T cells are present in these AAA lesions. These results were statistically significant by the bimodal distribution. Three of 5 of these patients were typed by DNA-based HLA-typing and all three expressed DRB1 alleles containing the DRβGln70 amino acid residue that has been demonstrated to be associated with AAA. All three patients exhibited clonally expanded T cells in AAA lesions. Four of the 5 patients with AAA who exhibited clonal expansions of α-chain TCR transcripts, also exhibited clonal expansions of β-chain TCR transcripts in AAA lesions, as we have demonstrated previously (J Immunol 192:4897, 2014). αβ TCR-expressing T cells infiltrating AAA lesions contain T-cell clones which have undergone proliferation and clonal expansion in vivo in response to as yet unidentified specific antigens that may be self or nonself. These results provide additional evidence supporting the hypothesis that AAA is a specific antigen-driven T-cell autoimmune disease.

Dilating Vascular Diseases: Pathophysiology and Clinical Aspects

Atherosclerotic disease of the vessels is a significant problem affecting mortality and morbidity all over the world. However, dilatation of the vessels either in the arterial system or in the venous territory is another vessel disease. Varicocele, pelvic, and peripheral varicose veins and hemorrhoids are aneurysms of the venous vascular regions and have been defined as dilating venous disease, recently. Coronary artery ectasia, intracranial aneurysm, and abdominal aortic aneurysm are examples of arterial dilating vascular diseases. Mostly, they have been defined as variants of atherosclerosis. Although there are some similarities in terms of pathogenesis, they are distinct from atherosclerotic disease of the vessels. In addition, pathophysiological and histological similarities and clinical coexistence of these diseases have been demonstrated both in the arterial and in the venous system. This situation underlies the thought that dilatation of the vessels in any vascular territory should be considered as a systemic vessel wall disease rather than being a local disease of any vessel. These patients should be evaluated for other dilating vascular diseases in a systematic manner.

Predictors Associated With Increased Prevalence of Abdominal Aortic Aneurysm in Chinese Patients with Atherosclerotic Risk Factors

OBJECTIVE/BACKGROUND

Epidemiological screening studies have demonstrated that the prevalence of abdominal aortic aneurysm (AAA) of Asian origin appears to be low and so increases uncertainty about the cost effectiveness of screening for AAAs in Chinese people. Some studies have demonstrated a higher prevalence of AAA in patients with atherosclerotic risk factors. The purpose of the study was to determine the prevalence of AAA and to explore the high risk group of AAA in Chinese patients with atherosclerotic risk factors.

METHODS

From November 2014 to July 2015, a prospective observational study was conducted in Guangdong General Hospital. In total, 1582 consecutive patients with atherosclerotic risk factors and undergoing coronary angiography for suspected or known coronary artery disease were enrolled to be screened for AAA by abdominal aortic ultrasound. Because of inadequate ultrasound image quality, the analysis was based on the 1541 (97.4%) patients whose abdominal aortic ultrasound images were adequate.

RESULTS

The prevalence of AAA was 1.6% in the whole study population and 2.9% in male patients aged over 65 years. In multivariate analysis, age ≥ 65 years (p = .029), smoking (p = .037), hypertension (p = .026), and aortic root diameter > 30 mm (p = .003) were independent predictors of AAA. The prevalence of AAA was 0% (0/153) in patients without any independent predictor, 0.6% (3/502) in patients with one predictor, 1.0% (6/597) in patients with two predictors, 4.8% (12/249) in patients with three predictors, and up to 10% (4/40) in patients with four predictors (p<.001; p value for trend < .001).

CONCLUSION

Age ≥ 65 years, smoking, hypertension, and aortic root diameter > 30 mm emerged as independent predictors of AAA in Chinese patients. Stepwise increases in the prevalence of AAA were found to depend on the number of independent predictors. Ultrasound screening for AAA could be considered in these high risk patients, especially those with three or four predictors.

Global and regional burden of aortic dissection and aneurysms: mortality trends in 21 world regions, 1990 to 2010

A comprehensive and systematic assessment of the global burden of aortic aneurysms (AA) has been lacking. Therefore, we estimated AA regional deaths and years of life lost (YLL) in 21 regions worldwide for 1990 and 2010. We used the GBD (Global Burden of Disease) 2010 study causes of death database and the cause of death ensemble modeling approach to assess levels and trends of AA deaths by age, sex, and GBD region. The global AA death rate per 100,000 population was 2.49 (95% CI: 1.78 to 3.27) in 1990 and 2.78 (95% CI: 2.04 to 3.62) in 2010. In 1990 and 2010, the highest mean death rates were in Australasia and Western Europe: 8.82 (95% CI: 6.96 to 10.79) and 7.69 (95% CI: 6.11 to 9.57) in 1990 and 8.38 (95% CI: 6.48 to 10.86) and 7.68 (95% CI: 6.13 to 9.54) in 2010. YLL rates by GBD region mirrored the mortality rate pattern. Overall, men had higher AA death rates than women: 2.86 (95% CI: 1.90 to 4.22) versus 2.12 (95% CI: 1.33 to 3.00) in 1990 and 3.40 (95% CI: 2.26 to 5.01) versus 2.15 (95% CI: 1.44 to 2.89) in 2010. The relative change in median death rate was +0.22 (95% CI: 0.10 to 0.33) in developed nations versus +0.71 (95% CI: 0.28 to 1.40) in developing nations. The smallest relative changes in median death rate were noted in North America high income, Central Europe, Western Europe, and Australasia, with estimates of +0.07 (95% CI: -0.26 to 0.37), +0.08 (95% CI: -0.02 to 0.23), +0.09 (95% CI: -0.02 to 0.21), and +0.22 (95% CI: -0.08 to 0.46), respectively. The largest increases were in Asia Pacific high income, Southeast Asia, Latin America tropical, Oceania, South Asia, and Central Sub-Saharan Africa. Women rather than men drove the increase in the Asia Pacific high-income region: the relative change in median rates was +2.92 (95% CI: 0.6 to 4.35) versus +1.05 (95% CI: 0.61 to 2.42). In contrast to high-income regions, the observed pattern in developing regions suggests increasing AA burden, which portends future health system challenges in these regions.

Structural analysis of adventitial collagen to feature aging and aneurysm formation in human aorta

OBJECTIVE

Adventitial collagen structure provides the aorta with tensile strength. Like other collagen-rich tissues, it can be affected by internal factors including aging and location. We determined whether the structural characteristics of human aortic adventitial collagen change with aging, location, and aneurysm formation.

METHODS

Nonatherosclerotic nonaneurysmal (NANA) human abdominal aortas were collected from 15 individuals who had died of noncardiovascular diseases (<40 years old, NANA young, n = 5; >60 years old, NANA old, n = 5). The architecture of adventitial collagen in the aortas was assessed by scanning electron microscopy, and fiber orientation was assessed by polarized microscopy with two-dimensional fast Fourier transform. We then analyzed retardation as an anisotropic property of adventitial collagen by polarized light microscopy. The orientation and retardation of NANA aortas were compared with those of abdominal aortic specimens from patients who were surgically treated for abdominal aortic aneurysm (AAA) (>60 years old, n = 11).

RESULTS

Adventitial collagen of the abdominal aortas on scanning electron microscopy images appeared as wavy, ropy fibers in aortas from young individuals (NANA young, n = 5) and were essentially flattened in those from older patents (NANA old, n = 5) and from those with AAA. Collagen fibers were thicker but sparser in the adventitia of aortas with AAA. Orientation maintained in the collagen fibers of NANA aortas (n = 15) on two-dimensional fast Fourier transform analysis was unrelated to either location or age and did not differ between NANA aortas and those with AAA. However, collagen fibrils in NANA aortas (n = 15) were significantly less retarded only at the level of the inferior mesenteric artery compared with other aortic locations. In addition, retardation was significantly reduced in abdominal aortas with AAA at the level of the inferior mesenteric artery.

CONCLUSIONS

The basic structure of adventitial collagen fiber was maintained in abdominal aortas regardless of location or age. Because the molecular structure at the subfibril level changed at abdominal aorta and enhanced in aortas with AAA, alterations in the molecular structure of adventitial collagen might be associated with aneurysmal formation.

Abdominal aortic aneurysm presenting as a claudication

Back pain and radiating pain to the legs are the most common symptoms encountered in routine neurosurgical practice and usually originates from neurogenic causes including spinal stenosis. The clinial symptoms are often confused with symptoms of peripheral neuropathy, musculo-skeletal disease and vascular disease in elderly patients. Because it is not easy to distinguish out the cause of symptoms by only physical examination, routine spinal MRI is checked first to rule out the spinal diseases in most outpatient clinics. Although it is obvious that spinal MRI is a very strong tool to investigate the spinal circumferences, most spine surgeons ignore the importance of looking at all aspects of their imaging and of remembering the extra-spinal causes of radiculopathy. A 68-year-old man who presented with a sudden aggravated both leg claudication. Although his symptom was mimicked for his long standing neurogenic claudication due to spinal stenosis diagnosed previously, abdominal aortic aneurysm(AAA) was found on routine lumbar MRI and it was repaired successfully. We emphasize to spinal surgeons the importance of remembering to look wider on routine MRI images when considering differential diagnoses in the outpatient clinic and to remember the extra-spinal causes of radiculopathy, especially when encountering in elderly patients.

Aneurysmal lesions of patients with abdominal aortic aneurysm contain clonally expanded T cells

Abdominal aortic aneurysm (AAA) is a common disease with often life-threatening consequences. This vascular disorder is responsible for 1-2% of all deaths in men aged 65 years or older. Autoimmunity may be responsible for the pathogenesis of AAA. Although it is well documented that infiltrating T cells are essentially always present in AAA lesions, little is known about their role in the initiation and/or progression of the disease. To determine whether T cells infiltrating AAA lesions contain clonally expanded populations of T cells, we amplified β-chain TCR transcripts by the nonpalindromic adaptor-PCR/Vβ-specific PCR and/or Vβ-specific PCR, followed by cloning and sequencing. We report in this article that aortic abdominal aneurysmal lesions from 8 of 10 patients with AAA contained oligoclonal populations of T cells. Multiple identical copies of β-chain TCR transcripts were identified in these patients. These clonal expansions are statistically significant. These results demonstrate that αβ TCR(+) T lymphocytes infiltrating aneurysmal lesions of patients with AAA have undergone proliferation and clonal expansion in vivo at the site of the aneurysmal lesion, in response to unidentified self- or nonself Ags. This evidence supports the hypothesis that AAA is a specific Ag-driven T cell disease.

Abdominal aortic aneurysms targeted by functionalized polysaccharide microparticles: a new tool for SPECT imaging

Aneurysm diagnostic is nowadays limited by the lack of technology that enables early detection and rupture risk prediction. New non invasive tools for molecular imaging are still required. In the present study, we present an innovative SPECT diagnostic tool for abdominal aortic aneurysm (AAA) produced from injectable polysaccharide microparticles radiolabeled with technetium 99m (^99mTc) and functionalized with fucoidan, a sulfated polysaccharide with the ability to target P-Selectin. P-Selectin is a cell adhesion molecule expressed on activated endothelial cells and platelets which can be found in the thrombus of aneurysms, as well as in other vascular pathologies.

Microparticles with a maximum hydrodynamic diameter of 4 µm were obtained by crosslinking the polysaccharides dextran and pullulan. They were functionalized with fucoidan. In vitro interactions with human activated platelets were assessed by flow cytometry that demonstrated a specific affinity of fucoidan functionalized microparticles for P-Selectin expressed by activated platelets. For in vivo AAA imaging, microparticles were radiolabeled with ^99mTc and intravenously injected into healthy and AAA rats obtained by elastase perfusion through the aorta wall. Animals were scanned by SPECT imaging. A strong contrast enhancement located in the abdominal aorta of AAA rats was obtained, while no signal was obtained in healthy rats or in AAA rats after injection of non-functionalized control microparticles. Histological studies revealed that functionalized radiolabeled polysaccharide microparticles were localized in the AAA wall, in the same location where P-Selectin was expressed.

These microparticles therefore constitute a promising SPECT imaging tool for AAA and potentially for other vascular diseases characterized by P-Selectin expression. Future work will focus on validating the efficiency of the microparticles to diagnose these other pathologies and the different stages of AAA. Incorporation of a therapeutic molecule is also considered.

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.

Importance of endothelial NF-κB signalling in vascular remodelling and aortic aneurysm formation

AIMS

Vascular remodelling and aortic aneurysm formation are induced mainly by inflammatory responses in the adventitia and media. However, relatively little is known about the mechanistic significance of endothelium in the pathogenesis of these vascular disorders. The transcription factor nuclear factor-kappa B (NF-κB) regulates the expressions of numerous genes, including those related to pro-inflammatory responses. Therefore, to investigate the roles of endothelial pro-inflammatory responses, we examined the impact of blocking endothelial NF-κB signalling on intimal hyperplasia and aneurysm formation.

METHODS AND RESULTS

To block endothelial NF-κB signalling, we used transgenic mice expressing dominant-negative IκBα selectively in endothelial cells (E-DNIκB mice). E-DNIκB mice were protected from the development of cuff injury-induced neointimal formation, in association with suppressed arterial expressions of cellular adhesion molecules, a macrophage marker, and inflammatory factors. In addition, the blockade of endothelial NF-κB signalling prevented abdominal aortic aneurysm formation in an experimental model, hypercholesterolaemic apolipoprotein E-deficient mice with angiotensin II infusion. In this aneurysm model as well, aortic expressions of an adhesion molecule, a macrophage marker, and inflammatory factors were suppressed with the inhibited expression and activity of matrix metalloproteinases in the aorta.

CONCLUSION

Endothelial NF-κB activation up-regulates adhesion molecule expression, which may trigger macrophage infiltration and inflammation in the adventitia and media. Thus, the endothelium plays important roles in vascular remodelling and aneurysm formation through its intracellular NF-κB signalling.

Noncardiac vascular disease in rheumatoid arthritis: increase in venous thromboembolic events?

OBJECTIVE

To investigate the incidence of noncardiac vascular disease in a community-based incidence cohort of patients with rheumatoid arthritis (RA) and compare it to that in the general population and to investigate trends in the incidence of noncardiac vascular disease in patients with RA.

METHODS

A population-based inception cohort of patients with incident RA between January 1, 1980 and December 31, 2007 in Olmsted County, Minnesota and a cohort of non-RA subjects from the same population base was assembled and followed up until December 31, 2008. Venous thromboembolic, cerebrovascular, and peripheral arterial events were ascertained by medical record review.

RESULTS

The study population included 813 patients with RA with a mean±SD age of 55.9±15.7 years (68% women) and an average length of followup of 9.6±6.9 years. Compared to non-RA subjects of similar age and sex, patients diagnosed as having RA between 1995 and 2007 had a higher incidence (%) of venous thromboembolism (cumulative incidence±SE 6.7±1.7 versus 2.8±1.1, respectively; P=0.005) but similar rates of cerebrovascular and peripheral arterial events. Among patients with RA, the incidence of venous thromboembolic, cerebrovascular, and peripheral arterial events was similar in the 1995-2007 time period compared to the 1980-1994 time period.

CONCLUSION

Our findings indicate that the incidence of venous thromboembolism is increased in patients with RA compared to non-RA subjects. The incidence of cerebrovascular events and peripheral vascular disease events is similar in patients with RA compared to non-RA subjects. Among patients with RA, the incidence of noncardiac vascular disease has remained stable in recent decades.

A positron emission tomography/computed tomography (PET/CT) evaluation of asymptomatic abdominal aortic aneurysms: another point of view

BACKGROUND

To assess the prevalence of increased (18)F-fluorodeoxyglucose (FDG) uptake in aneurysmal walls, adopting a case-control approach in a population of asymptomatic patients with abdominal aortic aneurysm (AAA).

METHODS

This study included 40 males (mean age: 74 years, range: 59-93 years), consecutive, white Caucasian patients, with asymptomatic infrarenal AAA. The mean diameter of AAA was 4.9 cm (range: 4.8-5.4 cm), detected by computed tomography (CT) scan. Control Subjects: 44 age-matched controls subjects (mean age: 71 years, range: 59-85 years, 24 males, 20 females) who were selected according to a case-control criterion among a population of patients without any clinical evidence of atherosclerotic disease. Patients and controls underwent simultaneous FDG-positron emission tomography (PET) and CT imaging from the skull base to the femoral neck by using an integrated PET/CT scanner. PET/CT studies were analysed both visually and quantitatively. For quantitative analysis, circular CT-based regions of interest (ROIs) were drawn on the AAA, on all the aortic segments, and on the large vessel included in the study (carotid, subclavian, and iliac arteries). FDG uptake was quantified by calculating the mean and maximum standardized uptake values (SUVs) within each ROI and normalizing for the blood-pool SUV to obtain the final target-to-background ratio. Arterial calcium load was graded according to a semiquantitative five-point scale based on calcification of the arterial ring.

RESULTS

Metabolic activity in the aneurysmal aortic segment was even lower with respect to both the adjacent--nonaneurysmal--samples of patient group and the corresponding arterial segments of control subjects (P < 0.001 and P < 0.01, respectively). In visual analysis, no patients showed an increased focal uptake of degree adequate to identify the aneurysmal arterial wall. AAA patients showed significantly higher values of total calcium load (ACL) than controls in ascending aorta and subclavian and iliac arteries (P < 0.01), and only in AAA patient group, a significant correlation was present between values of ACL in both iliac arteries and abdominal aorta on one side and wall metabolic activity in the same arteries on the other (P < 0.05).

CONCLUSIONS

In conclusion, our results suggest that FDG hot spot, as well an increased diffuse uptake of FDG, in PET/CT studies is an extremely rare finding in patients with AAA of diameter close to surgical indications.

Fast track echo of abdominal aortic aneurysm using a real pocket-ultrasound device at bedside

BACKGROUND

Ultraminiaturization of echographic systems extraordinarily provides the image "within" the clinical examination. Abdominal aorta aneurysm (AAA) diagnosis based on conventional evaluation with a dedicated operator and ultrasound machine is still controversial due to the lack of evidence of the proposed management and guidelines' cost-effectiveness. We hypothesized that less expensive ultraportable devices could identify AAA with the same level of accuracy as conventional approaches.

METHODS

A first step of this study was to validate the VSCAN's image capabilities in patients referred to the vascular Doppler laboratory. Abdominal aorta measurements were performed by an experienced physician using conventional equipment followed by a second blinded physician using the ultraportable device VSCAN. Then, 204 patients hospitalized in our cardiology institute were prospectively included for a systematic screening of AAA at bedside using the VSCAN in order to determine the feasibility and impact of fast track evaluation compared to clinical examination.

RESULTS

A strong correlation was obtained between measurements of abdominal aorta diameters using the two ultrasound systems (r = 0.98, CI: 0.97-0.99, P < 0.001) with 100% of agreement for AAA diagnosis. In the second part of the study, visualization and measurement of the transverse diameter of the abdominal aorta was obtained in 199 patients, resulting in a feasibility of 97.5%. Among these patients, 18 AAAs were detected, which corresponds to a prevalence of 9%, whereas clinical evaluation did not detect any of them. Patients with AAA were more likely men (77.77% vs. 57.45%, P < 0.05) and hypertensive (88.8% vs. 56.9%, P < 0.05) as compared to those without AAA. Two patients with large AAA were quickly referred to the surgery department.

CONCLUSION

Considering its low cost, diagnostic accuracy, and widespread availability, screening for AAA using an ultraportable ultrasound device such as VSCAN by an experienced physician is promising and should be used as an extension of routine physical examination in vascular patients.

Direct relationship between cell density and FDG uptake in asymptomatic aortic aneurysm close to surgical threshold: an in vivo and in vitro study

PURPOSE

Conflicting results have been reported about the clinical value of fluorodeoxyglucose (FDG) imaging in predicting the risk of rupture of abdominal aortic aneurysm (AAA). The present study tests the hypothesis that FDG uptake is low in asymptomatic noninflammatory AAA due to the low cell density in aneurysmal walls.

METHODS

Positron emission tomography (PET)/CT imaging was performed in 12 consecutive candidates for AAA surgical repair and in 12 age- and sex-matched controls. At intervention, aneurysmal walls were cut into three sequential blocks. Block A was frozen to cut three 5-μm slices for incubation with 2-3 MBq of FDG for 5 min. Block C was first incubated with the same tracer solution for the same time and subsequently frozen to cut three 5-μm slices. Autoradiographic images were coregistered with immunohistochemical pictures of cell density, type and DNA synthesis as assessed on block B.

RESULTS

No visible uptake in abdominal aorta occurred in any patient or control subject. Immunohistochemistry documented a severe loss of wall structure, with low numbers of cells. Tracer retention directly correlated with overall cell density and with prevalence of cells synthesizing DNA. The metabolic nature of FDG uptake was confirmed by the selective effect of preliminary freezing that decreased tracer content by 90% in regions with high cell density and only by 34% in cold acellular areas.

CONCLUSION

The loss of tissue structure and the marked decrease in cell density account for the low prevalence of positive findings at FDG PET imaging, at least in asymptomatic patients bearing AAAs whose diameter is close to surgical indication.

Cost-effectiveness of screening for abdominal aortic aneurysm in the Netherlands and Norway

Background

The aim of this study was to determine the cost-effectiveness of ultrasound screening for abdominal aortic aneurysm (AAA) in men aged 65 years, for both the Netherlands and Norway.

Methods

A Markov model was developed to simulate life expectancy, quality-adjusted life-years, net health benefits, lifetime costs and incremental cost-effectiveness ratios for both screening and no screening for AAA. The best available evidence was retrieved from the literature and combined with primary data from the two countries separately, and analysed from a national perspective. A threshold willingness-to-pay (WTP) of €20 000 and €62 500 was used for data from the Netherlands and Norway respectively.

Results

The additional costs of the screening strategy compared with no screening were €421 (95 per cent confidence interval 33 to 806) per person in the Netherlands, and the additional life-years were 0·097 (−0·180 to 0·365), representing €4340 per life-year. For Norway, the values were €562 (59 to 1078), 0·057 (−0·135 to 0·253) life-years and €9860 per life-year respectively. In Norway the results were sensitive to a decrease in the prevalence of AAA in 65-year-old men to 1 per cent, or lower. Probabilistic sensitivity analyses indicated that AAA screening has a 70 per cent probability of being cost-effective in the Netherlands with a WTP threshold of €20 000, and 70 per cent in Norway with a threshold of €62 500.

Conclusion

Using this model, screening for AAA in 65-year-old men would be highly cost-effective in both the Netherlands and Norway.

Acute abdominal pain in the older adult

Abdominal pain in older adults is a concerning symptom common to a variety of diagnoses with high morbidity and mortality. Organizing the differential into categories based on pathology (inflammatory, obstructive, vascular, or other causes) provides a framework for the history, physical, and diagnostic studies. An organized approach and treatment and considerations specific to the geriatric population are discussed.

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.

Initial stress and nonlinear material behavior in patient-specific AAA wall stress analysis

Rupture risk estimation of abdominal aortic aneurysms (AAA) is currently based on the maximum diameter of the AAA. A more critical approach is based on AAA wall stress analysis. For that, in most cases, the AAA geometry is obtained from CT-data and treated as a stress free geometry. However, during CT imaging, the AAA is subjected to a time-averaged blood pressure and is therefore not stress free. The aim of this study is to evaluate the effect of neglecting these initial stresses (IS) on the patient-specific AAA wall stress as computed by finite element analysis. Additionally, the contribution of the nonlinear material behavior of the AAA wall is evaluated. Thirty patients with maximum AAA diameters below the current surgery criterion were scanned with contrast-enhanced CT and the AAA's were segmented from the image data. The mean arterial blood pressure (MAP) was measured immediately after the CT-scan and used to compute the IS corresponding with the CT geometry and MAP. Comparisons were made between wall stress obtained with and without IS and with linear and nonlinear material properties. On average, AAA wall stresses as computed with IS were higher than without IS. This was also the case for the stresses computed with the nonlinear material model compared to the linear material model. However, omitting initial stress and material nonlinearity in AAA wall stress computations leads to different effects in the resulting wall stress for each AAA. Therefore, provided that other assumptions made are not predominant, IS cannot be discarded and a nonlinear material model should be used in future patient-specific AAA wall stress analyses.

Relation of common carotid artery lumen diameter to general arterial dilating diathesis and abdominal aortic aneurysms: the Tromsø Study

In a cross-sectional, population-based study in Tromsø, Norway, the authors investigated correlations between lumen diameter in the right common carotid artery (CCA) and the diameters of the femoral artery and abdominal aorta and whether CCA lumen diameter was a risk factor for abdominal aortic aneurysm (AAA). Ultrasonography was performed in 6,400 men and women aged 25-84 years during 1994-1995. An AAA was considered present if the aortic diameter at the level of renal arteries was greater than or equal to 35 mm, the infrarenal aortic diameter was greater than or equal to 5 mm larger than the diameter of the level of renal arteries, or a localized dilation of the aorta was present. CCA lumen diameter was positively correlated with abdominal aortic diameter (r = 0.3, P < 0.01) and femoral artery diameter (r = 0.2, P < 0.01). In a multivariable adjusted model, CCA lumen diameter was a significant predictor of AAA in both men and women (for the fifth quintile vs. the third, odds ratios were 1.9 (95% confidence interval: 1.2, 2.9) and 4.1 (95% confidence interval: 1.5, 10.8), respectively). Thus, CCA lumen diameter was positively correlated with femoral and abdominal aortic artery diameter and was an independent risk factor for AAA.

Chlamydial lipopolysaccharide (cLPS) is present in atherosclerotic and aneurysmal arterial wall--cLPS levels depend on disease manifestation

BACKGROUND

The role of Chlamydia pneumoniae in peripheral atherosclerosis disease and abdominal aortic aneurysm (AAA) remains unclear. Chlamydial lipopolysaccharide (cLPS) detection is a method used conventionally in routine chlamydial diagnosis of gynecological or ophthalmic samples.

METHODS

We compared cLPS concentrations, as well as other markers of bacterial load, in plaques and sera of patients operated on for carotid artery stenosis (n=110), aorto-occlusive disease (n=22), or AAAs (n=50) at the Helsinki University Central Hospital.

RESULTS

The median levels of cLPS in plaques were 2.28, 0.80, and 0.29 ng/ml in AAA, aorto-occlusive disease, and carotid artery stenosis patients, respectively (P<.001, Kruskal-Wallis). cLPS in serum correlated with LPS binding protein levels (Spearman's rho=0.52, P<.001), suggesting that the presence of chlamydiae is sufficient to produce an innate immune response reaction in these patients. Serum inflammatory markers interleukin 6 and highly sensitive C-reactive protein also correlate with cLPS (Spearman's rho=0.42 and 0.51, respectively, P<.001).

CONCLUSIONS

cLPS is present in arterial disease, and the potential role of C. pneumoniae in the pathogenesis of both peripheral atherosclerosis disease and AAA should not be forgotten. cLPS has a positive correlation with serum inflammatory markers, but this is no proof of a causal association.

Inhibition of development of experimental aortic abdominal aneurysm in rat model by atorvastatin through inhibition of macrophage migration

Recently, atherosclerosis has been considered to be the result of inflammation. Interestingly, hydroxymethylglutaryl-coenzyme (HMG-Co) A inhibitors (statins), which are clinically used as lipid-lowering agents, have been reported to have various anti-inflammatory effects. As abdominal aortic aneurysm (AAA) is a common degenerative condition associated with atherosclerosis, this study was designed to investigate the inhibitory effect of a statin, atorvastatin, on aneurysm formation apart from its lipid-lowering effect. We employed an elastase-induced rat AAA model, as statins do not lower cholesterol in rats. Mean aneurysm diameter was significantly smaller in the atorvastatin treatment group as compared to control at 4 weeks after surgery (P<0.05). Interestingly, atorvastatin inhibited the expression of ICAM and MCP-1, followed by the suppression of macrophage recruitment into the aortic wall at 1 week after operation. A significant reduction in MMP-12, but not MMP-2, -3 and -9, expression was also observed by treatment with atorvastatin at 1 week after surgery. In addition, synthesis of collagen and elastin in the vascular wall were significantly increased by atorvastatin. Here, the present study demonstrated a direct effect of atorvastatin to inhibit the progression of aortic aneurysm, independent of its lipid-lowering effect. This study suggests new therapeutic aspects of statins to inhibit the progression of aneurysms.

Abdominal Aortic Aneurysm

An abdominal aortic aneurysm (AAA) is defined as a localized dilation of the artery that is 1.5 times the diameter of the normal segment. The most common location for an aortic aneurysm is the infrarenal segment where a diameter that exceeds 3 cm in diameter is considered aneurysmal. Duplex ultrasonography and spiral computerized tomography are the imaging modalities most commonly performed to detect the longitudinal and transverse diameter of the aorta. The prevalence of AAA may be increasing. Smoking, male gender, and increasing age are the most powerful predictors of AAA. Considering the higher prevalence of hypertension, it is surprising that the prevalence of AAA among African-American men is 39% less than white men. The risk of rupture is independently associated with female gender, large initial aneurysm diameter, lower forced expiratory volume in the first second, current smoking, and higher mean blood pressure. Inflammation rather than atherosclerosis may be essential to the development of AAA. Treatment is directed at smoking cessation and control of blood pressure and lipids. Beta blockers (propranolol) have not been shown to modify aneurysm growth rates, but drop out rates in the studies have been high. Antibiotics do show a modest benefit. Surgery is generally performed when the aneurysm exceeds 5.5 cm in men. For women, an AAA size between 4.5 cm and 5.0 cm is recommended for elective repair.

Low vitamin B6, and not plasma homocysteine concentration, as risk factor for abdominal aortic aneurysm: a retrospective case-control study

BACKGROUND

Hyperhomocysteinemia has been associated with vascular disease in many epidemiologic studies, but only a few have reported on the relation between hyperhomocysteinemia and aneurysms of the abdominal aorta (AAAs). Although these studies showed higher homocysteine concentrations in patients with AAA than in controls, little attention had been given to possible confounding factors. Most patients with AAA are of older age, have an impaired renal function, and have other risk factors for cardiovascular disease. This matched case-control study investigated the relation between homocysteine concentration (before and after methionine loading) and AAA, taking into account possible confounders such as age, sex, and concentrations of creatinine and B vitamins.

METHODS

Patients with a history of AAA were recruited from the outpatient clinic; 60% had already undergone surgery for their AAA. They were asked to invite a friend or neighbor to participate as a control subject (age-matched and sex-matched). Concentrations of homocysteine, vitamin B6, vitamin B12, folate, and creatinine were determined in the fasting state, and blood was taken for methylenetetrahydrofolate reductase (MTHFR) mutation analysis. Six hours after oral methionine loading, the postmethionine load homocysteine concentration was determined.

RESULTS

Univariate analysis showed an odds ratio (OR) of 2.2 (95% confidence interval (CI), 0.9 to 5.5) for the risk of AAA for the highest quartile of homocysteine concentration. After adjustment for creatinine, the OR was markedly reduced to 1.24 (95% CI, 0.42 to 3.66), and this risk further attenuated in the multivariate analysis. Univariate analysis of the B vitamins showed an increased risk of AAA for the bottom quartile of vitamin B6 (OR, 3.75; 95% CI, 1.22 to 11.54), which even increased after adjustments. The relative risk associated with the MTHFR 677TT polymorphism was 2.1 (95% CI, 0.9 to 5.3).

CONCLUSION

Vitamin B6, but not homocysteine, is an independent risk factor for AAA. The role of vitamin B6 in the pathogenesis of AAA needs to be further elucidated.

Abdominal aortic aneurysm is a specific antigen-driven T cell disease

To determine whether monoclonal/oligoclonal T cells are present in abdominal aortic aneurysm (AAA) lesions, we amplified beta-chain T cell receptor (TCR) transcripts from these lesions by the nonpalindromic adaptor (NPA)-polymerase chain reaction (PCR)/V-beta-specific PCR followed by cloning and sequencing. Sequence analysis revealed the presence of substantial proportions of identical beta-chain TCR transcripts in AAA lesions in 9 of 10 patients examined, strongly suggesting the presence of oligoclonal populations of alphabeta TCR+ T cells. We have also shown the presence of oligoclonal populations of gammadelta TCR+ T cells in AAA lesions. Sequence analysis after appropriate PCR amplification and cloning revealed the presence of substantial proportions of identical VgammaI and VgammaII TCR transcripts in 15 of 15 patients examined, and of Vdelta1 and Vdelta2 TCR transcripts in 12 of 12 patients. These clonal expansions were very strong. All these clonal expansions were statistically significant by the binomial distribution. In other studies, we determined that mononuclear cells infiltrating AAA lesions express early- (CD69), intermediate- (CD25, CD38), and late- (CD45RO, HLA class II) activation antigens. These findings suggest that active ongoing inflammation is present in the aortic wall of patients with AAA. These results demonstrate that oligoclonal alphabeta TCR+ and gammadelta TCR+T cells are present in AAA lesions. These oligoclonal T cells have been clonally expanded in vivo in response to yet unidentified antigens. Although the antigenic specificity of these T cells remains to be determined, these T cells may play a significant role in the initiation and/or the propagation of the AAA. It appears that AAA is a specific antigen-driven T cell disease.

Pathology, natural history and treatment of abdominal aortic aneurysms

With increasing age of the population and improvement of diagnostic tools, the incidence of abdominal aortic aneurysms (AAA) has been rising steadily. Despite an improvement in operative and interventional treatment options, AAA is the cause of death in 1-3% of men over 65 years of age in industrial countries, mostly due to rupture [1]. Therefore, routine screening for AAA by ultrasonography has been postulated in the past: a 60 year old man with an abdominal aortic diameter of less than 3 cm has a life-time risk of developing AAA close to zero. However, routine screening has not been found to be cost effective. Despite of the results of two well-designed studies, the limits of AAA qualifying the patient for surgery or intervention in contrast to conservative treatment is still a matter of debate. The present review article summarizes the current knowledge of the pathology, incidence, risks, natural course as well as symptoms and current treatment strategies of AAA on the basis of the recent literature.

Hypertension accelerated experimental abdominal aortic aneurysm through upregulation of nuclear factor kappaB and Ets

In this study, we focused on the effect of hypertension on the transcription factors nuclear factor kappaB (NFkappaB) and ets in the mechanisms of abdominal aortic aneurysm (AAA), and we investigated how hypertension affects the progression of AAA. AAA was produced by elastase perfusion in hypertensive rats and normotensive rats. The size of AAA rapidly increased in hypertensive rats as compared with normotensive rats. Western blot analysis demonstrated that the expression of matrix metalloproteinase (MMP)-2, -3 , -9, and -12, as well as intercellular adhesion molecule, was increased in hypertensive AAA rats, accompanied by upregulation of NFkappaB and ets. Moreover, in situ zymography showed that the activity of MMPs was increased in the aorta of a hypertensive AAA model as compared with that in a normotensive AAA model. Interestingly, transfection of chimeric decoy oligodeoxynucleotide (ODN) resulted in significant inhibition of aortic dilatation both in normotensive and hypertensive rats at 4 weeks after transfection. Destruction of elastic fibers was also significantly inhibited by transfection of chimeric decoy ODN in both hypertensive rats and normotensive rats. The expression of MMP-2, -3, -9, and -12, as well as intercellular adhesion molecule, was significantly attenuated by the chimeric decoy ODN, accompanied by inhibition of the migration of macrophages. Also, the effect of chimeric decoy ODN was confirmed in an organ culture. The present study demonstrated that hypertension accelerated the progression of experimental AAA through upregulation of NFkappaB and ets. Inhibition of NFkappaB and ets could be a novel therapeutic strategy to treat AAA in hypertensive patients.

Severe extra-articular disease manifestations are associated with an increased risk of first ever cardiovascular events in patients with rheumatoid arthritis

BACKGROUND

Rheumatoid arthritis is associated with increased cardiovascular mortality and morbidity.

OBJECTIVE

To assess the effect of severe extra-articular rheumatoid arthritis (ExRA) manifestations on the risk of cardiovascular disease (CVD) in patients with rheumatoid arthritis.

METHODS

Patients with ExRA (n = 81) according to predefined criteria and controls (n = 184) without evidence of extra-articular disease were identified from a large research database of patients with rheumatoid arthritis. In a structured review of the medical records, the occurrence and the date of onset of clinically diagnosed CVD events were noted. Cox proportional hazards models were used to estimate the effect of ExRA on the risk of first ever CVD events after the diagnosis of rheumatoid arthritis. ExRA manifestations were modelled as time-dependent covariates, with adjustment for age, sex and smoking at the diagnosis of rheumatoid arthritis. Onset of erosive disease and rheumatoid factor seropositivity were entered as time-dependent variables. Patients were followed until onset of CVD, death or loss to follow-up.

RESULTS

ExRA was associated with a significantly increased risk of first ever CVD events (p<0.001), and also with an increased risk of new-onset coronary artery disease, adjusted for age, sex and smoking (hazard ratio (HR): 3.16; 95% confidence interval (95% CI: 1.58 to 6.33). The association between ExRA and any first ever CVD event remained significant when controlling for age, sex, smoking, rheumatoid factor and erosive disease (HR: 3.25; 95% CI: 1.59 to 6.64).

CONCLUSION

Severe ExRA manifestations are associated with an increased risk of CVD events in patients with rheumatoid arthritis. This association is not due to differences in age, sex, smoking, rheumatoid factor or erosive joint damage. It is suggested that systemic extra-articular disease is a major determinant of cardiovascular morbidity in rheumatoid arthritis.

Abdominal Aortic Aneurysm Repair in Octogenarians: Outcomes and Predictors

OBJECTIVES

This study was undertaken to evaluate predictors and outcomes of octogenarians who underwent abdominal aortic aneurysm repair.

DESIGN

A prospective observational study.

MATERIALS AND METHODS

Between January 1st, 1997 and April 15th, 2005, 31 octogenarians were admitted to our Department with the diagnosis of abdominal aortic aneurysm. Mean follow-up time was 53.7+/-27.2 months. All patients were in good clinical condition and represented a selected healthy group of octogenarians.

RESULTS

The overall perioperative (30-days) mortality rate was 3.1%. The total in-hospital morbidity rate was 22.6%. Overall survival estimates at 48 and 96 months were 81+/-8% and 46+/-21%, respectively. The actuarial freedom from aneurysm-related death at 48 and 96 months was 96+/-4% and 96+/-4%, respectively. The actuarial freedom from aneurysm-unrelated death at 48 and 96 months was 84+/-7% and 48+/-21%. Only coronary artery disease was a significant predictor of survival using multivariate stepwise logistic regression analysis.

CONCLUSIONS

In this series, AAA surgery was carried out in selected octogenarians without affecting long-term survival.

Community-based, nonprofit organization-sponsored ultrasonography screening program for abdominal aortic aneurysms is effective at identifying occult aneurysms

Early diagnosis of abdominal aortic aneurysm (AAA), prior to rupture, is vital for optimizing patient survival. An abdominal ultrasonography examination of an asymptomatic individual to check for the presence of an AAA, however, is not presently reimbursed by health insurance in the United States. This article reports the results of one nonprofit, community-based screening program, run by Aneurysm Outreach, Inc. (AOI; www.alink.org). AOI offered free screening for AAA to anyone who met the criteria of being (1) over 60 years old; (2) over 50 years old, male, and with positive family history for AAA; or (3) over 55 years old, female, and with positive family history for AAA. AOI organized 21 ultrasonographic screening events between September 2001 and November 2004, and the number of participants per event varied from 24 to 240. Altogether 3,088 individuals met the screening criteria and 22 of them were already known to have AAAs. Thirty-six (1.2%) individuals were excluded from the final analysis due to poor quality of the ultrasonographic images. Among the remaining 3,030 individuals, a dilatation of the aorta was detected and confirmed in 61 (2.0%) individuals, in 4.3% of the screened males and in 0.6% of the screened females. Thirteen individuals had their AAAs repaired surgically. The frequencies of males and current smokers were significantly higher in the AAA group than in the group with normal-size aorta (male AAA 83.6% vs. normal 42.0%, p < 0.0001; smoker AAA 54.9% vs. normal 18.1%, p < 0.0001). The mean age was significantly higher in the AAA group than in the group with normal-size aorta (AAA 71.0 +/- 6.2 vs. normal 68.4 +/- 7.0, p = 0.005). In conclusion, the results of this community-based free ultrasonographic screening program are in agreement with randomized controlled screening programs and emphasize the need for systematic screening programs and the importance of finding individuals harboring AAAs before their rupture.