Evolution of the wall shear stresses during the progressive enlargement of symmetric abdominal aortic aneurysms

Salsac, Anne‐Virginie; Sparks, Steven R.; Chomaz, Jean‐Marc; Lasheras, Juan C.

doi:10.1017/s002211200600036x

Cited by 103 publications

(100 citation statements)

References 63 publications

(49 reference statements)

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“…This description of the flow phenomena in pulsatile flow through a Gaussian shaped model aneurysm agrees very well with what was found in experiments by Salsac et al (2006). These authors also observed that the vortex motions within the dilatation induce strong spatial and temporal variations of the wall shear stress, especially near the distal end.…”

Section: Discussionsupporting

confidence: 89%

“…Again, this agrees with what was found by us. Our computational approach allowed us to investigate a somewhat larger range of parameter values than Salsac et al (2006). Our results support the conclusion of Salsac et al (2006) that longer aneurysms are less pathological than short ones.…”

Section: Discussionsupporting

confidence: 74%

“…Recently, several studies have been carried out to elucidate how these differences may affect the pathogenesis of abdominal aneurysms. The studies of Salsac et al (2006) and Sheard (2009) were based on a flow rate waveform obtained from a healthy male subject at rest. The difficulty is that the flow rate waveform varies significantly with the location in the aorta.…”

Section: Fluid Flowmentioning

confidence: 99%

“…Various quantities have been introduced by different authors to investigate the response of endothelial cells to wall shear stress variations. Examples are the cycle-averaged wall shear stress and the cycle-averaged magnitude of that stress, quantities that are defined as in Salsac et al (2006),…”

Section: Numerical Proceduresmentioning

confidence: 99%

“…The pulsatile flow rate waveform in this comparison is that used by Salsac et al (2006) and Sheard (2009), which is called Q3 here and is shown in figure 26. The flow parameters have the values Re = 330 and Wo = 10.7.…”

Section: Sensitivity To Geometrical Detailsmentioning

confidence: 99%

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Dynamics of pulsatile flow through model abdominal aortic aneurysms

2014

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To contribute to the understanding of flow phenomena in abdominal aortic aneurysms, numerical computations of pulsatile flows through aneurysm models and a stability analysis of these flows were carried out. The volume flow rate waveforms into the aneurysms were based on measurements of these waveforms, under rest and exercise conditions, of patients suffering abdominal aortic aneurysms. The Reynolds number and Womersley number, the dimensionless quantities that characterize the flow, were varied within the physiologically relevant range, and the two geometric quantities that characterize the model aneurysm were varied to assess the influence of the length and maximal diameter of an aneurysm on the details of the flow. The computed flow phenomena and the induced wall shear stress distributions agree well with what was found in PIV measurements by Salsac et al. (J. Fluid Mech., vol. 560, 2006, pp. 19-51). The results suggest that long aneurysms are less pathological than short ones, and that patients with an abdominal aortic aneurysm are better to avoid physical exercise. The pulsatile flows were found to be unstable to three-dimensional disturbances if the aneurysm was sufficiently localized or had a sufficiently large maximal diameter, even for flow conditions during rest. The abdominal aortic aneurysm can be viewed as acting like a 'wavemaker' that induces disturbed flow conditions in healthy segments of the arterial system far downstream of the aneurysm; this may be related to the fact that one-fifth of the larger abdominal aortic aneurysms are found to extend into the common iliac arteries. Finally, we report a remarkable sensitivity of the wall shear stress distribution and the growth rate of three-dimensional disturbances to small details of the aneurysm geometry near the proximal end. These findings suggest that a sensitivity analysis is appropriate when a patient-specific computational study is carried out to obtain a quantitative description of the wall shear stress distribution.

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Section: Discussionsupporting

confidence: 89%

Section: Discussionsupporting

confidence: 74%

Section: Fluid Flowmentioning

confidence: 99%

Section: Numerical Proceduresmentioning

confidence: 99%

Section: Sensitivity To Geometrical Detailsmentioning

confidence: 99%

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Dynamics of pulsatile flow through model abdominal aortic aneurysms

2014

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A comparison of hemodynamic metrics and intraluminal thrombus burden in a common iliac artery aneurysm

Kelsey

Powell

Norman

et al. 2016

Numer Methods Biomed Eng

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Aneurysms of the common iliac artery (CIAA) are most commonly seen in association with an abdominal aortic aneurysm (AAA). Isolated CIAAs, in the absence of an AAA, are uncommon. Similar to AAAs, CIAA may develop intraluminal thrombus (ILT). As isolated CIAAs have a contralateral common iliac artery for comparison, they provide an opportunity to study the haemodynamic mechanisms behind ILT formation.In this study, we compared a large isolated CIAA and the contralateral iliac artery using computational fluid dynamics (CFD) to determine if haemodynamic metrics correlate with the location of ILT. We performed a comprehensive CFD study and investigated the residence time of platelets and monocytes, velocity fields, time-averaged wall shear stress (TAWSS), oscillatory shear index (OSI) and endothelial cell activation potential (ECAP). We then correlated these data to ILT burden determined with computed tomography (CT).We found that high cell residence times, low TAWSS, high OSI and high ECAP all correlate with regions of ILT development. Our results show agreement with previous hypotheses of thrombus formation in AAA and provide insights into the computational haemodynamics of iliac artery aneurysms.

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Investigation of the hemodynamic flow conditions and blood‐induced stresses inside an abdominal aortic aneurysm by means of a SPH numerical model

Aricò

Sinagra

Nagy

et al. 2019

Numer Methods Biomed Eng

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The estimation of blood flow-induced loads occurring on the artery wall is affected by uncertainties hidden in the complex interaction of the pulsatile flow, the mechanical parameters of the artery, and the external support conditions. To circumvent these difficulties, a specific tool is developed by combining the aorta displacements measured by an electrocardiogram-gated-computed tomography angiography, with the blood velocity field computed by a smoothed particle hydrodynamics (SPH) numerical model. In the present work, the SPH model has been specifically adapted to the solution of the 3D Navier-Stokes equations inside a domain with boundaries of prescribed motion. Images of the abdominal aorta aneurysm (AAA) of a 44-year-old female patient were acquired during a stabilized cardiac cycle by electrocardiogram-gated-computed tomography angiography. The in vivo kinematic field inside the pulsating arterial wall was estimated by using recent technology, which makes it possible to follow the shape of the arterial wall during a cardiac cycle. We compare the flow conditions and the blood-induced loads, computed by the numerical model under the assumption of a moving arterial wall, with the corresponding results obtained assuming three rigid wall geometries of the vessel during the cardiac cycle. Significant differences were found for the wall shear stress distribution. K E Y W O R D Saneurysm, arterial wall, infrarenal abdominal aorta, moving boundary, shear stresses, SPH | INTRODUCTIONAbdominal aortic aneurysms (AAAs) are localized and permanent dilatation of the infrarenal abdominal aorta. The related health risk is due to thrombus growth and development, rupture of the aortic wall, and degenerative effects of endothelial cells because of alteration of the flow field inside the aortic lumen. 1 The origin and development of AAAs are not clearly understood. The coupling between physiological changes of the intimal and medial layers of the arterial wall and the mechanical stimuli of the hemodynamic stresses acting on the vessel wall could be one of the origins. 2-5 Past studies 6,7 have shown that the "disturbed" flow conditions inside the lumen, such as regions of high and very low values of wall shear stress (WSS), and large temporal and spatial WSS gradients,

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Evolution of the wall shear stresses during the progressive enlargement of symmetric abdominal aortic aneurysms

Cited by 103 publications

References 63 publications

Dynamics of pulsatile flow through model abdominal aortic aneurysms

Dynamics of pulsatile flow through model abdominal aortic aneurysms

A comparison of hemodynamic metrics and intraluminal thrombus burden in a common iliac artery aneurysm

Investigation of the hemodynamic flow conditions and blood‐induced stresses inside an abdominal aortic aneurysm by means of a SPH numerical model

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