Analysis of flow patterns in a patient-specific thoracic aortic aneurysm model

Tan, F. P. P.; Borghi, Alessandro; Mohiaddin, Raad H.; Wood, Nigel B.; Thom, Simon; Xu, Xiao Yun

doi:10.1016/j.compstruc.2008.09.007

Cited by 75 publications

(55 citation statements)

References 56 publications

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“…34,37,38,41,42 However, in a large amount of computational studies on thoracic aorta hemodynamics, a constant flow rate division is prescribed at the supra-aortic branches, as in scheme S1, generally assuming that 5% of the total inlet mass flows into each branch during the entire cardiac cycle. 8,[21][22][23]36 From our measurements, it is evident that (1) a 5% average flow diversion in every branch is not a realistic approximation for subject-specific models, as confirmed by other studies, 37,42 and that (2) there is no reason to believe that the flow diversion is constant during the cardiac cycle. 34 As previously discussed, the flow diversion toward the supra-aortic vessels affects flow separation and reattachment conditions and as a consequence WSS-based indicators values.…”

Section: Discussionsupporting

confidence: 76%

On the Use of In Vivo Measured Flow Rates as Boundary Conditions for Image-Based Hemodynamic Models of the Human Aorta: Implications for Indicators of Abnormal Flow

et al. 2011

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The purpose of this study is to investigate how the imposition of personalized, non-invasively measured blood flow rates as boundary conditions (BCs) influences image-based computational hemodynamic studies in the human aorta. We extracted from 4D phase-contrast MRI acquisitions of a healthy human (1) the geometry of the thoracic aorta with supra-aortic arteries and (2) flow rate waveforms at all boundaries. Flow simulations were carried out, and the implications that the imposition of different BC schemes based on the measured flow rates have on wall shear stress (WSS)-based indicators of abnormal flow were analyzed. Our results show that both the flow rate repartition among the multiple outlets of the aorta and the distribution and magnitude of the WSS-based indicators are strongly influenced by the adopted BC strategy. Keeping as reference hemodynamic model the one where the applied BC scheme allowed to obtain a satisfactory agreement between the computed and the measured flow rate waveforms, differences in WSS-based indicators up to 49% were observed when the other BC strategies were applied. In conclusion, we demonstrate that in subject-specific computational hemodynamics models of the human aorta the imposition of BC settings based on non-invasively measured flow rate waveforms influences indicators of abnormal flow to a large extent. Hence, a BCs set-up assuring realistic, subject-specific instantaneous flow rate distribution must be applied when BCs such as flow rates are prescribed.

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Section: Discussionsupporting

confidence: 76%

On the Use of In Vivo Measured Flow Rates as Boundary Conditions for Image-Based Hemodynamic Models of the Human Aorta: Implications for Indicators of Abnormal Flow

et al. 2011

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“…The flow patterns observed here, are characterized by helical flow and large recirculation zone. Same results found in literature for the blood flow in presence of the aneurysm (Tan et al, 2008;Boutsianis et al, 2009). Disturbed flow induced by sudden expansion of the flow stream, results in additional stresses acting on the aneurysm wall that may be responsible for further aortic dilation.…”

Section: Discussionsupporting

confidence: 73%

“…Regions of high WSS are likely to lead to matrix degradation by expression of plasmin, matrix-metalloproteinases and smooth muscle cells apoptosis (Ekaterinas et al, 2006). This may cause degenerative lesions of aneurysmal wall, altering the wall thickness and eventually causing rupture (Tan et al, 2008).…”

Section: Wall Shear Stress Analysismentioning

confidence: 99%

An analysis of blood flow dynamics in AAA

Bernad¹,

Bernad²,

Barbat³

et al. 2011

Etiology, Pathogenesis and Pathophysiology of Aortic Aneurysms and Aneurysm Rupture

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“…The computationally cheaper RANS models are used for computing the flow in more complex geometries. From the various RANS models proposed to model arterial flows [15,45,46] it is probably the k − models [47] that are considered most suitable to describe the turbulent behaviour of these confined flows. Hence, the validation of these models for clinically relevant problems will certainly be the topic of future research.…”

Section: Discussionmentioning

confidence: 99%

Towards computational modelling of aortic stenosis

Loon

2009

Numer Methods Biomed Eng

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SUMMARYIn this paper fluid-structure interaction models of bioprosthetic or native aortic valves are proposed for the assessment of aortic stenosis severity. The fictitious domain approach is applied for the blood-valve interaction and the valve and root geometry are defined such that geometrical changes can easily be made. Clinically relevant scenarios are demonstrated using the models by introducing variable stroke volumes, differently shaped valve and root, leaflet fusion or calcifications. Systolic behaviour of the valves is observed and the severity of the occlusions is evaluated using the following clinically relevant criteria: geometrical orifice area, trans-valvular pressure gradient, effective orifice area and Energy loss coefficient. Within this context, the benefits, shortcomings and potential of the presented three-dimensional models are identified and discussed.

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Analysis of flow patterns in a patient-specific thoracic aortic aneurysm model

Cited by 75 publications

References 56 publications

On the Use of In Vivo Measured Flow Rates as Boundary Conditions for Image-Based Hemodynamic Models of the Human Aorta: Implications for Indicators of Abnormal Flow

On the Use of In Vivo Measured Flow Rates as Boundary Conditions for Image-Based Hemodynamic Models of the Human Aorta: Implications for Indicators of Abnormal Flow

An analysis of blood flow dynamics in AAA

Towards computational modelling of aortic stenosis

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