Regional distribution of wall thickness and failure properties of human abdominal aortic aneurysm

Raghavan, Madhavan L.; Kratzberg, Jarin; Tolosa, Erasmo Magalhães Castro de; Hanaoka, Mauro; Walker, P. J.; Silva, Erasmo Simão da

doi:10.1016/j.jbiomech.2005.10.021

Cited by 236 publications

(255 citation statements)

References 13 publications

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“…The present model was an idealized model of an abdominal aorta lacking the non-uniformities in geometry in real patient data. A uniform wall thickness was chosen in aneurismal and non-aneurismal vessels, which were not realistic, especially in fully developed aneurysms [12,23,72]. Vessel wall remodeling during the development of an aneurysm was also disregarded in the study.…”

Section: Discussionmentioning

confidence: 99%

“…In computational simulations, vessel stress is calculated as a function of the vessel diameter [7,34], wall thickness [36,37], asymmetry [14,18,34,36], tortuosity [21], material property [17,24,29,38], calcification [15,22], intraluminal thrombus (ILT) [5,15,16,33], and blood flow [4, 9, 13, 14, 17, 20, 25, 26, 28-30, 32, 35-41]. Blood vessel strength is measured by ex vivo studies [11,12,23,31,44] or estimated by effective features such as ILT existence, sex, and genetic vulnerability [10]. Medical treatment techniques of aneurysms, mainly stent applications, are also investigated [35,40].…”

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confidence: 99%

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Investigation of material modeling in fluid–structure interaction analysis of an idealized three-layered abdominal aorta: aneurysm initiation and fully developed aneurysms

Şimşek

Kwon

2015

J Biol Phys

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Different material models for an idealized three-layered abdominal aorta are compared using computational techniques to study aneurysm initiation and fully developed aneurysms. The computational model includes fluid-structure interaction (FSI) between the blood vessel and the blood. In order to model aneurysm initiation, the medial region was degenerated to mimic the medial loss occurring in the inception of an aneurysm. Various cases are considered in order to understand their effects on the initiation of an abdominal aortic aneurysm. The layers of the blood vessel were modeled using either linear elastic materials or Mooney-Rivlin (otherwise known as hyperelastic) type materials. The degenerated medial region was also modeled in either linear elastic or hyperelastic-type materials and assumed to be in the shape of an arc with a thin width or a circular ring with different widths. The blood viscosity effect was also considered in the initiation mechanism. In addition, dynamic analysis of the blood vessel was performed without interaction with the blood flow by applying time-dependent pressure inside the lumen in a three-layered abdominal aorta. The stresses, strains, and displacements were compared for a healthy aorta, an initiated aneurysm and a fully developed aneurysm. The study shows that the material modeling of the vessel has a sizable effect on aneurysm initiation and fully developed aneurysms. Different material modeling of degeneration regions also affects the stressstrain response of aneurysm initiation. Additionally, the structural analysis without considering FSI (called noFSI) overestimates the peak von Mises stress by 52% at the interfaces of the layers.

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Investigation of material modeling in fluid–structure interaction analysis of an idealized three-layered abdominal aorta: aneurysm initiation and fully developed aneurysms

Şimşek

Kwon

2015

J Biol Phys

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“…Uniaxial stretch tests showed AAA specimen to be stiffer, less distensible, with decreased wall strength than healthy aortic tissue, attributed to their lower elastin content. 21,41,62 Initially, uniaxial testing of abdominal aortic tissue specimens was used to characterize the mechanical behavior of the tissue by using nonlinear hyperelastic material models of the isotropic Mooney-Rivlin formulation. 33,39 However, biaxial testing of AAA specimens that was used to characterize the directional stress-strain properties of the tissue, 56 indicated that AAA tissue is better characterized by hyperelastic material models with anisotropic properties, e.g., orthotropic material models.…”

Section: Biomechanical Propertiesmentioning

confidence: 99%

Patient-Based Abdominal Aortic Aneurysm Rupture Risk Prediction with Fluid Structure Interaction Modeling

et al. 2010

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Abstract-Elective repair of abdominal aortic aneurysm (AAA) is warranted when the risk of rupture exceeds that of surgery, and is mostly based on the AAA size as a crude rupture predictor. A methodology based on biomechanical considerations for a reliable patient-specific prediction of AAA risk of rupture is presented. Fluid-structure interaction (FSI) simulations conducted in models reconstructed from CT scans of patients who had contained ruptured AAA (rAAA) predicted the rupture location based on mapping of the stresses developing within the aneurysmal wall, additionally showing that a smaller rAAA presented a higher rupture risk. By providing refined means to estimate the risk of rupture, the methodology may have a major impact on diagnostics and treatment of AAA patients.

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“…The observation of a regional variation in the mechanical properties confirms the hypothesis that the degradation of the properties in the ATAA is localized rather than uniform [34]. To address the issue of the inhomogeneity of the ATAA, particularly when attempting to identify potential rupture conditions, it is necessary to consider the variation in mechanical properties at the millimeter scale [25,26,37].…”

Section: Introductionmentioning

confidence: 53%

Local mechanical properties of human ascending thoracic aneurysms

Davis

Luo

Avril

et al. 2016

Journal of the Mechanical Behavior of Biomedical Materials

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Ascending thoracic aortic aneurysms (ATAAs) are focal, asymmetric dilatations of the aortic wall which are prone to rupture. To identify potential rupture locations in advance, it is necessary to consider the inhomogeneity of the ATAA at the millimeter scale. Towards this end, we have developed a combined experimental and computational approach using bulge inflation tests, digital image correlation (DIC), and an inverse membrane approach to characterize the pointwise stress, strain, and hyperelastic properties of the ATAA. Using this approach, the pointwise hyperelastic material properties were identified on 10 human ATAA samples collected from patients undergoing elective surgery to replace their ATAAs with a graft. Our method was able to capture the varying levels of heterogeneity in the ATAA from regional to local. It was shown for the first time that the material properties in the ATAA are unmistakably heterogeneous at length scales between 1 mm and 1 cm, which are length scales where vascular tissue is typically treated as homogeneous. The distributions of the material properties for each patient were also examined to study the inter-and intra-patient variability. Large inter-subject variability was observed in the elastic properties.

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Regional distribution of wall thickness and failure properties of human abdominal aortic aneurysm

Cited by 236 publications

References 13 publications

Investigation of material modeling in fluid–structure interaction analysis of an idealized three-layered abdominal aorta: aneurysm initiation and fully developed aneurysms

Investigation of material modeling in fluid–structure interaction analysis of an idealized three-layered abdominal aorta: aneurysm initiation and fully developed aneurysms

Patient-Based Abdominal Aortic Aneurysm Rupture Risk Prediction with Fluid Structure Interaction Modeling

Local mechanical properties of human ascending thoracic aneurysms

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