scholarly journals Oxidative Stress and Inflammatory Markers in Abdominal Aortic Aneurysm

Antioxidants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 602
Author(s):  
David Sánchez-Infantes ◽  
Meritxell Nus ◽  
Miquel Navas-Madroñal ◽  
Joan Fité ◽  
Belén Pérez ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Abdominal Aortic Aneurysm ◽  
Aortic Aneurysm ◽  
Wall Stress ◽  
Ultrasound Screening ◽  
Element Analysis ◽  
Inflammatory Infiltration ◽  
Screening Programs ◽  
Aneurysmal Wall ◽  
Abdominal Aortic

Abdominal aortic aneurysm (AAA) is increasing due to aging of the population and is a major cause of death among the elderly. Ultrasound screening programs are useful in early diagnosis, but aneurysm size is not always a good predictor of rupture. Our aim was to analyze the value of circulating molecules related to oxidative stress and inflammation as new biomarkers to assist the management of AAA. The markers were quantified by ELISA, and their expression in the aneurysmal wall was studied by real-time PCR and by immunostaining. Correlation analysis of the studied markers with aneurysm diameter and peak wall stress (PWS), obtained by finite element analysis, and multivariate regression analysis to assess potential confounding factors were performed. Our study shows an extensive inflammatory infiltration in the aneurysmal wall, mainly composed by T-cells, macrophages and B-cells and altered levels of reactive oxygen species (ROS), IgM, IgG, CD38, GDF15, S100A4 and CD36 in plasma and in the aneurysmal tissue of AAA patients compared with controls. Circulating levels of IgG, CD38 and GDF15 positively correlated with abdominal aortic diameter, and CD38 was correlated with PWS. Our data show that altered levels of IgG, CD38 and GDF15 have potential diagnostic value in the assessment of AAA.

scholarly journals A Methodology for the Derivation of Unloaded Abdominal Aortic Aneurysm Geometry With Experimental Validation

2016 ◽  
Vol 138 (10) ◽  
Author(s):  
Santanu Chandra ◽  
Vimalatharmaiyah Gnanaruban ◽  
Fabian Riveros ◽  
Jose F. Rodriguez ◽  
Ender A. Finol
Keyword(s):  
Finite Element ◽  
Abdominal Aortic Aneurysm ◽  
Aortic Aneurysm ◽  
Stress Component ◽  
Wall Stress ◽  
Patient Specific ◽  
Element Analysis ◽  
Nodal Surface ◽  
Abdominal Aortic ◽  
Peak Wall Stress

In this work, we present a novel method for the derivation of the unloaded geometry of an abdominal aortic aneurysm (AAA) from a pressurized geometry in turn obtained by 3D reconstruction of computed tomography (CT) images. The approach was experimentally validated with an aneurysm phantom loaded with gauge pressures of 80, 120, and 140 mm Hg. The unloaded phantom geometries estimated from these pressurized states were compared to the actual unloaded phantom geometry, resulting in mean nodal surface distances of up to 3.9% of the maximum aneurysm diameter. An in-silico verification was also performed using a patient-specific AAA mesh, resulting in maximum nodal surface distances of 8 μm after running the algorithm for eight iterations. The methodology was then applied to 12 patient-specific AAA for which their corresponding unloaded geometries were generated in 5–8 iterations. The wall mechanics resulting from finite element analysis of the pressurized (CT image-based) and unloaded geometries were compared to quantify the relative importance of using an unloaded geometry for AAA biomechanics. The pressurized AAA models underestimate peak wall stress (quantified by the first principal stress component) on average by 15% compared to the unloaded AAA models. The validation and application of the method, readily compatible with any finite element solver, underscores the importance of generating the unloaded AAA volume mesh prior to using wall stress as a biomechanical marker for rupture risk assessment.

Towards Patient-Specific Modeling of an Enlarging Abdominal Aortic Aneurysm

2009 ◽  
Author(s):  
S. Zeinali-Davarani ◽  
A. Sheidaei ◽  
S. Baek
Keyword(s):  
Abdominal Aortic Aneurysm ◽  
Aortic Aneurysm ◽  
Patient Specific ◽  
Element Analysis ◽  
Computational Framework ◽  
Aneurysmal Wall ◽  
Constrained Mixture ◽  
Abdominal Aortic ◽  
Modeling Stress ◽  
Patient Specific Modeling

There has been a clear need for better understanding of the progression of abdominal aortic aneurysm (AAA) and obtaining reliable prediction of the AAA rupture. Finite element analysis (FEA) using non-axisymmetric models of AAAs provides better estimation of stress distribution in the aneurysmal wall with complex shapes [1]. However, FEA alone does not provide a mathematical description for the evolution of an AAA through growth and remodeling (G&R). A computational framework for modeling stress-mediated growth and structural remodeling of the arterial wall under physiological and pathological conditions has been suggested using a constrained mixture assumption [2]. Stress-mediated enlargement of intracranial aneurysms has been investigated using idealized axisymmetric geometries [3,4]. The kinetics of stress-mediated turnover of collagen fiber families and degradation of elastin were found to have particular importance in the G&R of aneurysmal wall.

Automated Methodology for Determination of Stress Distribution in Human Abdominal Aortic Aneurysm

2005 ◽  
Vol 127 (5) ◽  
pp. 868-871 ◽  
Author(s):  
Madhavan L. Raghavan ◽  
Mark F. Fillinger ◽  
Steven P. Marra ◽  
Bernhard P. Naegelein ◽  
Francis E. Kennedy
Keyword(s):  
Abdominal Aortic Aneurysm ◽  
Aortic Aneurysm ◽  
Peak Stress ◽  
Wall Stress ◽  
Patient Specific ◽  
Element Analysis ◽  
Biomechanical Stress ◽  
Abdominal Aortic ◽  
Study Population ◽  
Peak Wall Stress

Knowledge of impending abdominal aortic aneurysm (AAA) rupture can help in surgical planning. Typically, aneurysm diameter is used as the indicator of rupture, but recent studies have hypothesized that pressure-induced biomechanical stress may be a better predictor. Verification of this hypothesis on a large study population with ruptured and unruptured AAA is vital if stress is to be reliably used as a clinical prognosticator for AAA rupture risk. We have developed an automated algorithm to calculate the peak stress in patient-specific AAA models. The algorithm contains a mesh refinement module, finite element analysis module, and a postprocessing visualization module. Several aspects of the methodology used are an improvement over past reported approaches. The entire analysis may be run from a single command and is completed in less than 1h with the peak wall stress recorded for statistical analysis. We have used our algorithm for stress analysis of numerous ruptured and unruptured AAA models and report some of our results here. By current estimates, peak stress in the aortic wall appears to be a better predictor of rupture than AAA diameter. Further use of our algorithm is ongoing on larger study populations to convincingly verify these findings.

Abdominal Aortic Aneurysm Rupture Risk Assessment Exploiting Dynamic (4D) CT Based Wall Motion Data and Finite Element Analysis

2013 ◽  
Author(s):  
Eleni Metaxa ◽  
Vasileios Vavourakis ◽  
Nikolaos Kontopodis ◽  
Konstantinos Pagonidis ◽  
Christos V. Ioannou ◽  
...  
Keyword(s):  
Abdominal Aortic Aneurysm ◽  
Aortic Aneurysm ◽  
Risk Estimation ◽  
Wall Stress ◽  
Aneurysm Rupture ◽  
Patient Specific ◽  
Rupture Risk ◽  
Element Analysis ◽  
Motion Data ◽  
Abdominal Aortic

Abdominal aortic aneurysm (AAA) disease is primarily a degenerative process, where rupture occurs when stress exerted on the aortic wall exceeds its failure strength. Therefore, knowledge of both the wall stress distribution and the mechanical properties of the AAA wall is required for patient specific rupture risk estimation.

scholarly journals The Association of Wall Mechanics and Morphology: A Case Study of Abdominal Aortic Aneurysm Growth

2011 ◽  
Vol 133 (10) ◽  
Author(s):  
Christopher B. Washington ◽  
Judy Shum ◽  
Satish C. Muluk ◽  
Ender A. Finol
Keyword(s):  
Abdominal Aortic Aneurysm ◽  
Aortic Aneurysm ◽  
Wall Stress ◽  
Aneurysm Rupture ◽  
Maximum Diameter ◽  
Least Squares Regression ◽  
Surveillance Period ◽  
Element Analysis ◽  
Abdominal Aortic ◽  
Peak Wall Stress

The purpose of this study is to evaluate the potential correlation between peak wall stress (PWS) and abdominal aortic aneurysm (AAA) morphology and how it relates to aneurysm rupture potential. Using in-house segmentation and meshing software, six 3-dimensional (3D) AAA models from a single patient followed for 28 months were generated for finite element analysis. For the AAA wall, both isotropic and anisotropic materials were used, while an isotropic material was used for the intraluminal thrombus (ILT). These models were also used to calculate 36 geometric indices characteristic of the aneurysm morphology. Using least squares regression, seven significant geometric features (p < 0.05) were found to characterize the AAA morphology during the surveillance period. By means of nonlinear regression, PWS estimated with the anisotropic material was found to be highly correlated with three of these features: maximum diameter (r = 0.992, p = 0.002), sac volume (r = 0.989, p = 0.003) and diameter to diameter ratio (r = 0.947, p = 0.033). The correlation of wall mechanics with geometry is nonlinear and reveals that PWS does not increase concomitantly with aneurysm diameter. This suggests that a quantitative characterization of AAA morphology may be advantageous in assessing rupture risk.

scholarly journals Abdominal Aortic Aneurysm: Evolving Controversies and Uncertainties

2018 ◽  
Vol 27 (02) ◽  
pp. 058-080 ◽  
Author(s):  
Davide Carino ◽  
Timur Sarac ◽  
Bulat Ziganshin ◽  
John Elefteriades
Keyword(s):  
Abdominal Aortic Aneurysm ◽  
Animal Models ◽  
Aortic Aneurysm ◽  
Abdominal Aorta ◽  
Renal Arteries ◽  
Ultrasound Screening ◽  
Screening Programs ◽  
Abdominal Aortic ◽  
Risk Of Rupture

AbstractAbdominal aortic aneurysm (AAA) is defined as a permanent dilatation of the abdominal aorta that exceeds 3 cm. Most AAAs arise in the portion of abdominal aorta distal to the renal arteries and are defined as infrarenal. Most AAAs are totally asymptomatic until catastrophic rupture. The strongest predictor of AAA rupture is the diameter. Surgery is indicated to prevent rupture when the risk of rupture exceeds the risk of surgery. In this review, we aim to analyze this disease comprehensively, starting from an epidemiological perspective, exploring etiology and pathophysiology, and concluding with surgical controversies. We will pursue these goals by addressing eight specific questions regarding AAA: (1) Is the incidence of AAA increasing? (2) Are ultrasound screening programs for AAA effective? (3) What causes AAA: Genes versus environment? (4) Animal models: Are they really relevant? (5) What pathophysiology leads to AAA? (6) Indications for AAA surgery: Are surgeons over-eager to operate? (7) Elective AAA repair: Open or endovascular? (8) Emergency AAA repair: Open or endovascular?

scholarly journals Predictors of Abdominal Aortic Aneurysm Risks

2020 ◽  
Vol 7 (3) ◽  
pp. 79
Author(s):  
Stephen J. Haller ◽  
Amir F. Azarbal ◽  
Sandra Rugonyi
Keyword(s):  
Risk Assessment ◽  
Abdominal Aortic Aneurysm ◽  
Aortic Aneurysm ◽  
Wall Stress ◽  
Patient Specific ◽  
Rupture Risk ◽  
Element Analysis ◽  
Computational Biomechanics ◽  
Wall Strength ◽  
Abdominal Aortic

Computational biomechanics via finite element analysis (FEA) has long promised a means of assessing patient-specific abdominal aortic aneurysm (AAA) rupture risk with greater efficacy than current clinically used size-based criteria. The pursuit stems from the notion that AAA rupture occurs when wall stress exceeds wall strength. Quantification of peak (maximum) wall stress (PWS) has been at the cornerstone of this research, with numerous studies having demonstrated that PWS better differentiates ruptured AAAs from non-ruptured AAAs. In contrast to wall stress models, which have become progressively more sophisticated, there has been relatively little progress in estimating patient-specific wall strength. This is because wall strength cannot be inferred non-invasively, and measurements from excised patient tissues show a large spectrum of wall strength values. In this review, we highlight studies that investigated the relationship between biomechanics and AAA rupture risk. We conclude that combining wall stress and wall strength approximations should provide better estimations of AAA rupture risk. However, before personalized biomechanical AAA risk assessment can become a reality, better methods for estimating patient-specific wall properties or surrogate markers of aortic wall degradation are needed. Artificial intelligence methods can be key in stratifying patients, leading to personalized AAA risk assessment.

Wall Stress Studies of Abdominal Aortic Aneurysm in a Clinical Model

2001 ◽  
Vol 15 (3) ◽  
pp. 355-366 ◽  
Author(s):  
Mano J. Thubrikar ◽  
Jihad Al-Soudi ◽  
Francis Robicsek
Keyword(s):  
Abdominal Aortic Aneurysm ◽  
Aortic Aneurysm ◽  
Wall Stress ◽  
Clinical Model ◽  
Stress Studies ◽  
Abdominal Aortic

scholarly journals The Role of Geometric Parameters in the Prediction of Abdominal Aortic Aneurysm Wall Stress

2010 ◽  
Vol 39 (1) ◽  
pp. 42-48 ◽  
Author(s):  
E. Georgakarakos ◽  
C.V. Ioannou ◽  
Y. Kamarianakis ◽  
Y. Papaharilaou ◽  
T. Kostas ◽  
...  
Keyword(s):  
Abdominal Aortic Aneurysm ◽  
Aortic Aneurysm ◽  
Wall Stress ◽  
Geometric Parameters ◽  
Aneurysm Wall ◽  
Abdominal Aortic ◽  
Abdominal Aortic Aneurysm Wall

Abstract 297: Segmental Aortic Stiffening is a Mechanism Driving Early Abdominal Aortic Aneurysm Pathogenesis

2014 ◽  
Vol 34 (suppl_1) ◽  
Author(s):  
Uwe Raaz ◽  
Alexander M Zöllner ◽  
Ryuji Toh ◽  
Futoshi Nakagami ◽  
Isabel N Schellinger ◽  
...  
Keyword(s):  
Abdominal Aortic Aneurysm ◽  
Aortic Aneurysm ◽  
Aortic Wall ◽  
Ex Vivo ◽  
Wall Stress ◽  
Finite Elements Analysis ◽  
External Application ◽  
Abdominal Aortic ◽  
Aneurysm Growth ◽  
Aortic Stiffening

Stiffening of the aortic wall is a phenomenon consistently observed in abdominal aortic aneurysm (AAA). However, its role in AAA pathophysiology is largely undefined. Using an established murine elastase-induced AAA model, we demonstrate that segmental aortic stiffening (SAS) precedes aneurysm growth. Finite elements analysis (FEA)-based wall stress calculations reveal that early stiffening of the aneurysm-prone aortic segment leads to axial (longitudinal) stress generated by cyclic (systolic) tethering of adjacent, more compliant wall segments. Interventional stiffening of AAA-adjacent segments (via external application of surgical adhesive) significantly reduces aneurysm growth. These changes correlate with reduced segmental stiffness of the AAA-prone aorta (due to equalized stiffness in adjacent aortic segments), reduced axial wall stress, decreased production of reactive oxygen species (ROS), attenuated elastin breakdown, and decreased expression of inflammatory cytokines and macrophage infiltration, as well as attenuated apoptosis within the aortic wall. Cyclic pressurization of stiffened aortic segments ex vivo increases the expression of genes related to inflammation and extracellular matrix (ECM) remodeling. Finally, human ultrasound studies reveal that aging, a significant AAA risk factor, is accompanied by segmental infrarenal aortic stiffening. The present study introduces the novel concept of segmental aortic stiffening (SAS) as an early pathomechanism generating aortic wall stress and thereby triggering AAA growth. Therefore monitoring SAS by ultrasound might help to better identify patients at risk for AAA disease and better predict the susceptibility of small AAA to further growth. Moreover our results suggest that interventional mechanical stiffening of the AAA-adjacent aorta may be further tested as a novel treatment option to limit early AAA growth.

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