Arterio-Venous Fistula: Two Cases Realistic Numerical Blood Flow Simulations

Kharboutly, Zaher; Treutenaere, J.M.; Claude, I.; Legallais, Cécile

doi:10.1109/iembs.2007.4352955

Cited by 4 publications

(4 citation statements)

References 8 publications

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“…Our results are in line with previous CFD investigations of AVFs both in idealized and patient specific models presented at only one time instant. 8,14,15 Flow patterns in the curved regions of the geometry resulted in higher WSS values on the outer curvature and lower WSS on the inner curvature. The low WSS areas corresponded to recirculation regions.…”

Section: Discussionmentioning

confidence: 98%

“…36 In AVF investigations, CFD was shown to be a powerful tool for describing flow fields in both idealized models and patient specific geometries. 4,8,15 However, those analyses were performed at single time points, and do not provide a comprehensive correlation of flow factors to the vessel remodeling that is observed in longitudinal studies.…”

Section: Introductionmentioning

confidence: 99%

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Vascular Remodeling in Autogenous Arterio-Venous Fistulas by MRI and CFD

et al. 2012

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Hemodynamic parameters play an important role in regulating vascular remodeling in arterio-venous fistula (AVF) maturation. Investigating the changes in hemodynamic parameters during AVF maturation is expected to improve our understanding of fistula failure, but very little data on actual temporal changes in human AVFs is available. The present study aimed to assess the feasibility of using a noncontrast-enhanced MRI protocol combined with CFD modeling to relate hemodynamic changes to vascular remodeling following native AVF placement. MR angiography (MRA) and MR velocimetry (MRV) data was acquired peri-operatively, 1 month, and 3 months later in three patients. Vascular geometries were obtained by segmentation of the MRA images. Pulsatile flow simulations were performed in the patient specific vascular geometries with time-dependent boundary conditions prescribed from MRV measurements. A principal result of the study is the description of WSS changes over time in the same patients. The disturbed flow observed in the venous segments resulted in a variability of the WSS distribution and could be responsible for the non-uniform remodeling of the vessel. The artery did not show regions of disturbed flow upstream from the anastomosis, which would be consistent with the uniform remodeling. MRI use demonstrated the ability to provide a comprehensive evaluation of clinically relevant information for the investigation of upper extremity AVFs. 3D geometry from MRA in combination with MRV provides the opportunity to perform detailed CFD analysis of local hemodynamics in order to determine flow descriptors affecting fistula maturation.

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Section: Discussionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Vascular Remodeling in Autogenous Arterio-Venous Fistulas by MRI and CFD

et al. 2012

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“…The images have been segmented and the complete AVF lumen has been reconstructed following the method described by Kharboutly et al . In order to image the artery and the vein during the same acquisition, a contrast bolus was injected in the patient's opposite arm.…”

Section: Methodsmentioning

confidence: 99%

“…We first mesh the lateral surface of the lumen and then generate the volume mesh of the fluid domain. The latter consists of a hybrid mesh, with seven prismatic cells in the boundary layer and tetrahedral cells in the vessel core (see for more details on the mesh generation).…”

Section: Methodsmentioning

confidence: 99%

Numerical simulation of the fluid structure interactions in a compliant patient‐specific arteriovenous fistula

Decorato

Kharboutly

Vassallo

et al. 2013

Numer Methods Biomed Eng

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The objective of the study is to investigate numerically the fluid-structure interactions (FSI) in a patient-specific arteriovenous fistula (AVF) and analyze the degree of complexity that such a numerical simulation requires to provide clinically relevant information. The reference FSI simulation takes into account the non-Newtonian behavior of blood, as well as the variation in mechanical properties of the vascular walls along the AVF. We have explored whether less comprehensive versions of the simulation could still provide relevant results. The non-Newtonian blood model is necessary to predict the hemodynamics in the AVF because of the predominance of low shear rates in the vein. An uncoupled fluid simulation provides informative qualitative maps of the hemodynamic conditions in the AVF; quantitatively, the hemodynamic parameters are accurate within 20% maximum. Conversely, an uncoupled structural simulation with non-uniform wall properties along the vasculature provides the accurate distribution of internal wall stresses, but only at one instant of time within the cardiac cycle. The FSI simulation advantageously provides the time-evolution of both the hemodynamic and structural stresses. However, the higher computational cost renders a clinical use still difficult in routine.

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