scholarly journals Effect of intraluminal thrombus on wall stress in patient-specific models of abdominal aortic aneurysm

2002 ◽  
Vol 36 (3) ◽  
pp. 598-604 ◽  
Author(s):  
David H.J. Wang ◽  
Michel S. Makaroun ◽  
Marshall W. Webster ◽  
David A. Vorp
Keyword(s):  
Abdominal Aortic Aneurysm ◽  
Aortic Aneurysm ◽  
Wall Stress ◽  
Patient Specific ◽  
Intraluminal Thrombus ◽  
Abdominal Aortic

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.

Intraluminal thrombus and risk of rupture in patient specific abdominal aortic aneurysm – FSI modelling

2009 ◽  
Vol 12 (1) ◽  
pp. 73-81 ◽  
Author(s):  
Danny Bluestein ◽  
Kris Dumont ◽  
Matthieu De Beule ◽  
John Ricotta ◽  
Paul Impellizzeri ◽  
...  
Keyword(s):  
Abdominal Aortic Aneurysm ◽  
Aortic Aneurysm ◽  
Patient Specific ◽  
Intraluminal Thrombus ◽  
Abdominal Aortic ◽  
Risk Of Rupture

Effect of Variations in Intraluminal Thrombus Constitutive Properties on Abdominal Aortic Aneurysm Wall Stress: A Parametric Study

2001 ◽  
Author(s):  
Elena S. Di Martino ◽  
David H. J. Wang ◽  
Alberto Redaelli ◽  
Michel S. Makaroun ◽  
David A. Vorp
Keyword(s):  
Abdominal Aortic Aneurysm ◽  
Aortic Aneurysm ◽  
Parametric Study ◽  
Wall Stress ◽  
Transverse Diameter ◽  
Intraluminal Thrombus ◽  
Arterial Blood ◽  
Aneurysm Wall ◽  
Abdominal Aortic ◽  
Constitutive Parameters

Abstract The prevalence of abdominal aortic aneurysm (AAA) is growing together with population age, being 8.8% in a population above 65 years according to a recent study [1]. Deciding between elective surgical repair of AAA and watchful management is a complex issue due to the lack of reliable rupture risk indices. The maximum transverse diameter of AAA is most commonly used in clinical practice to base this decision. From a biomechanical viewpoint, AAA rupture is related to the balance between the stresses acting on the wall and strength of the wall tissue. Many different factors contribute to the stress within the aortic aneurysm wall, including the presence of intraluminal thrombus (ILT) [2–5], the local surface curvature [6] and material characteristics of the AAA wall [7], and the presence of local “stress concentrators” due to calcifications or local thinning. As regards the ILT, its role with respect to aneurysm wall stresses has given rise to many hypotheses. Some studies show that the pressure inside the thrombus is not reduced with respect to the arterial blood pressure, some, including studies from the authors, state a possible protective role [2–5]. Previously in our laboratory, a nonlinear, hyperelastic constitutive model was developed for ILT, and the parameters for which were determined through ex-vivo experimentation [8]. The purpose of this study was to investigate the reliability of using the same population-mean values of ILT constitutive parameters for estimates of wall stress distribution in all AAA. For this, we performed a parametric study in which the ELT constitutive parameters were varied within a physiological range and aortic wall stresses were evaluated.

A Large Strain Hyperelastic Constitutive Model for Intraluminal Thrombus From Abdominal Aortic Aneurysm

1999 ◽  
Author(s):  
David H. J. Wang ◽  
Michel S. Makaroun ◽  
Marshall W. Webster ◽  
David A. Vorp
Keyword(s):  
Abdominal Aortic Aneurysm ◽  
Aortic Aneurysm ◽  
Constitutive Model ◽  
Large Strain ◽  
Constitutive Models ◽  
Wall Stress ◽  
Accurate Estimation ◽  
Elastic Model ◽  
Intraluminal Thrombus ◽  
Abdominal Aortic

Abstract Rupture of abdominal aortic aneurysm (AAA) occurs when the wall stress acting on the dilated aortic wall exceeds the strength of the tissue. Therefore, accurate estimation of the wall stress distribution in AAA may be a clinically useful tool to predict their rupture. A majority of AAA contains a laminated, stationary, intraluminal thrombus (ILT) (Harter et al., 1982). Previous investigations have shown that ILT may significantly alter the wall stress acting on AAA (Inzoli et al., 1993; Mower et al., 1997; Stringfellow et al., 1987; Vorp et al., 1998; Di Martino et al., 1998). However, all of those studies used a simplified linear elastic model for ILT. This is inappropriate and can lead to inaccuracies since both AAA wall and contained ILT undergo large deformation during the cardiac cycle (Vorp et al., 1996). Therefore, to accomplish accurate stress analysis of AAA, appropriate constitutive models for both the wall and ILT are necessary. Our group has previously proposed a finite strain constitutive model for the AAA wall (Raghavan et al., in press). The purpose of this work was to derive a more suitable constitutive model and the associated mechanical properties for the ILT within AAA.

Patient-specific models of wall stress in abdominal aortic aneurysm: a comparison between MR and CT

2006 ◽  
Author(s):  
Sander de Putter ◽  
Marcel Breeuwer ◽  
Frans N. van de Vosse ◽  
Ursula Kose ◽  
Frans A. Gerritsen
Keyword(s):  
Abdominal Aortic Aneurysm ◽  
Aortic Aneurysm ◽  
Wall Stress ◽  
Patient Specific ◽  
Abdominal Aortic

Fully Coupled vs. Partially Coupled Fluid-Structure Interaction Methods for Patient-Specific Abdominal Aortic Aneurysm Biomechanics

2007 ◽  
Author(s):  
Christine M. Scotti ◽  
Ender A. Finol
Keyword(s):  
Abdominal Aortic Aneurysm ◽  
Aortic Aneurysm ◽  
Fluid Structure Interaction ◽  
Wall Stress ◽  
Patient Specific ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Abdominal Aortic ◽  
Mechanical Factors ◽  
Fully Coupled

Primary among the mechanical factors linked with abdominal aortic aneurysm (AAA) rupture is peak wall stress, frequently quantified as either the maximum principal or Von Mises stress exerted along the diseased arterial wall. Intraluminal pressure, as an impinging normal force on the wall, has been hypothesized as the dominant influence on this stress and thus the majority of numerical modeling studies of AAA mechanics have focused on static computational solid stress (CSS) predictions [1,2]. Unfortunately, retrospective studies comparing the magnitude of wall stress with the failure strength of the aneurysmal wall have yet to consistently predict the outcome for patient-specific AAAs [3,4]. Previous studies have shown that hemodynamics also plays a significant role in both the biological and mechanical factors that exist within AAAs. In the present investigation, partially and fully coupled fluid-structure interaction (p-FSI and f-FSI, respectively) computations of patient-specific AAA models are presented and compared to identify the effect of fluid flow in the biomechanical environment of these aneurysms.

Sign in / Sign up

Export Citation Format

Share Document