Repression of wall shear stress inside cerebral aneurysm at bifurcation of anterior cerebral artery by stents

Yamaguchi, Ryuhei; Tanaka, Gaku; Líu, Hao; Ujiié, Hiroshi

doi:10.1007/s00380-015-0665-1

Cited by 3 publications

(4 citation statements)

References 30 publications

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“…A simple bare-metal stent was used for two aneurysm models represented by spherical intracranial aneurysms induced at the side wall and the apex of bifurcation [28,29] , where aneurysms often develop and rupture (Figs.1 and 2) (cases 1 and 2, respectively) [30] . The first model (case 1) has a spherical aneurysm at the side wall.…”

Section: Methodsmentioning

confidence: 99%

“…With an inner diameter d 0 = 7 mm of straight circular tube, the aneurysm was ideally spherical with neck width (N), depth (D) and aspect ratio (AR) of 10 mm, 10 mm and 1.0, respectively [33] . Figure 2 shows a schema of the geometry of the aneurysm model that simulates a saccular intracranial aneurysm at the apex of bifurcation between the arterial cerebral artery (ACA) (A1-A2) and anterior communicating artery (ACoA) [29] . The model was connected to an afferent tube (diameter, d 0 = 8 mm) representing the proximal section of ACA (A1), and to efferent tubes (diameter, d 1 = 6 mm and d 2 = 3 mm) representing the distal section of ACA (A2) and the lateral section of ACoA, respectively.…”

Section: Methodsmentioning

confidence: 99%

“…Furthermore, since in this aneurysm model it is difficult to realize the size of 2.2 mm as diameter of the afferent vessel [32] , the diameter of 8mm in the afferent vessel was selected (approximately 4 fold larger than that of human ACA (A1)). We adjusted the mean Reynolds number of about 435 in ACA (A1) [29] .…”

Section: Methodsmentioning

confidence: 99%

“…Schema of aneurysm model at apex of bifurcation with stent (AR = 2.0). Reprinted with permission[29].…”

mentioning

confidence: 99%

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Suppression of Wall Shear Stress inside Intracranial Aneurysms by Simple Stents

et al. 2018

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The effect of a simple bare-metal stent on suppression of wall shear stress inside a spherical intracranial aneurysm model was experimentally examined by two dimensional particle image velocimetry in vitro. The flow model simulated an intracranial aneurysm induced both at the side wall and at the apex of bifurcation in the cerebral arteries. In order to assess the simple bare metal stent characteristics, the variation of wall shear stress was examined using both stented and non-stented models. The flow behavior inside the stented aneurysm was not smooth and wall shear stress was significantly smaller inside the aneurysm. For both models, the maximum and the temporal and spatial averaged wall shear stress in the stented model is reduced by at least 50 % smaller than those in the non-stented models. Stent deployment effectively suppresses the temporal and spatial variations, and the magnitude of wall shear stress. Consequently, even simple stent might be an effective treatment to retard the progress of cerebral aneurysms.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

“…Schema of aneurysm model at apex of bifurcation with stent (AR = 2.0). Reprinted with permission[29].…”

mentioning

confidence: 99%

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Suppression of Wall Shear Stress inside Intracranial Aneurysms by Simple Stents

et al. 2018

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Effects of arterial blood flow on walls of the abdominal aorta: distributions of wall shear stress and oscillatory shear index determined by phase-contrast magnetic resonance imaging

et al. 2015

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Although abdominal aortic aneurysms (AAAs) occur mostly inferior to the renal artery, the mechanism of the development of AAA in relation to its specific location is not yet clearly understood. The objective of this study was to evaluate the hypothesis that even healthy volunteers may manifest specific flow characteristics of blood flow and alter wall shear or oscillatory shear stress in the areas where AAAs commonly develop. Eight healthy male volunteers were enrolled in this prospective study, aged from 24 to 27. Phase-contrast magnetic resonance imaging (MRI) was performed with electrocardiographic triggering. Flow-sensitive four-dimensional MR imaging of the abdominal aorta, with three-directional velocity encoding, including simple morphological image acquisition, was performed. Information on specific locations on the aortic wall was applied to the flow encodes to calculate wall shear stress (WSS) and oscillatory shear index (OSI). While time-framed WSS showed the highest peak of 1.14 ± 0.25 Pa in the juxtaposition of the renal artery, the WSS plateaued to 0.61 Pa at the anterior wall of the abdominal aorta. The OSI peaked distal to the renal arteries at the posterior wall of the abdominal aorta of 0.249 ± 0.148, and was constantly elevated in the whole abdominal aorta at more than 0.14. All subjects were found to have elevated OSI in regions where AAAs commonly occur. These findings indicate that areas of constant peaked oscillatory shear stress in the infra-renal aorta may be one of the factors that lead to morphological changes over time, even in healthy individuals.

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