Numerical Evaluation and Experimental Validation of Pressure Drops Across a Patient-Specific Model of Vascular Access for Hemodialysis

Botti, Lorenzo Alessio; Canneyt, Koen Van; Kaminsky, Rado; Claessens, Tom; Planken, R. Nils; Verdonck, Pascal; Remuzzi, Andrea; Antiga, Luca

doi:10.1007/s13239-013-0162-6

Cited by 22 publications

(29 citation statements)

References 31 publications

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“…These values are substantially lower than those obtained in previous studies that observed unsteady flow in the vein. 43,44,51 This is in line with the expectation that more stable flow is associated with a reduced pressure drop.…”

Section: Pressure Dropssupporting

confidence: 87%

“…The nature of this recirculating region changes through the pulse cycle. However, fine-scale separated vortical structures, associated with highfrequency flow unsteadiness in previous studies, [42][43][44]51,55 are absent.…”

Section: Methodsmentioning

confidence: 66%

“…We note that this mesh resolution is lower than that employed by Iori et al 42 However, it is similar to that employed in other studies of unsteady flow in AVF. 43,51 Moreover, performance of the optimal configuration will be assessed with a higher-resolution simulation in Sec. III.…”

Section: Methodsmentioning

confidence: 99%

“…25 More recent work, undertaken specifically in the context of vascular fluid mechanics, includes studies of stenotic flows, 26 pulsatile flow in curved pipes, [27][28][29][30] flow in helical pipes, [31][32][33][34] and flow at junctions. [35][36][37] In terms of simulating flow in AVF configurations, there have been a range of previous Computational Fluid Dynamics (CFD) studies, including 1D simulations, [38][39][40] 2D simulations, 41 3D simulations with rigid walls in idealised geometries, [42][43][44][45][46][47] 3D simulations with rigid walls in more realistic geometries, [48][49][50][51][52][53][54][55] and simulations with distensible walls. 56 Of these studies, several investigated flow unsteadiness.…”

Section: Introductionmentioning

confidence: 99%

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Suppressing unsteady flow in arterio-venous fistulae

et al. 2017

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Arterio-Venous Fistulae (AVF) are regarded as the “gold standard” method of vascular access for patients with end-stage renal disease who require haemodialysis. However, a large proportion of AVF do not mature, and hence fail, as a result of various pathologies such as Intimal Hyperplasia (IH). Unphysiological flow patterns, including high-frequency flow unsteadiness, associated with the unnatural and often complex geometries of AVF are believed to be implicated in the development of IH. In the present study, we employ a Mesh Adaptive Direct Search optimisation framework, computational fluid dynamics simulations, and a new cost function to design a novel non-planar AVF configuration that can suppress high-frequency unsteady flow. A prototype device for holding an AVF in the optimal configuration is then fabricated, and proof-of-concept is demonstrated in a porcine model. Results constitute the first use of numerical optimisation to design a device for suppressing potentially pathological high-frequency flow unsteadiness in AVF.

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Section: Pressure Dropssupporting

confidence: 87%

Section: Methodsmentioning

confidence: 66%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Suppressing unsteady flow in arterio-venous fistulae

et al. 2017

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“…Principle Quantity Measurement type pressure sensor [37,17,18,4,6,39,38,11,10,26] various pressure bulk, instantaneous, ≥ kHz flow sensor [35,37,17,18,6,39,38,11,10,26] various flow rate bulk, instantaneous, ≥ kHz LDV [35] optical velocity point, instantaneous, ≥ kHz VDUS [22,21] acoustic velocity point, average * , O(10) Hz PIV [4,19,12,2,27,15,28,3] optical velocity grid of points, instantaneous, O(10) Hz UIV [20] acoustic velocity grid of points, instantaneous, O(10 − 1000) Hz PLIF [3] optical concentration 2D plane, instantaneous, O(10) Hz CDUS [22,21] acoustic velocity 2D plane, average * , O(10) Hz Different methods exist to measure bulk pressure and flow rate, including Pitot tube-type and piezo-electric pressure sensors, and paddle wheel or ultrasoundbased flow rate sensors (for more information, see e.g. [36]).…”

Section: Methodsmentioning

confidence: 99%

Review of Experimental Modelling in Vascular Access for Hemodialysis

Drost

Alam

Houston

et al. 2017

Cardiovasc Eng Tech

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This paper reviews applications of experimental modelling in vascular access for hemodialysis. Different techniques that are used in in-vitro experiments are bulk pressure and flow rate measurements, Laser Doppler Velocimetry (LDV) and Vector Doppler Ultrasound (VDUS) point velocity measurements, and wholefield measurements such as Particle Image Velocimetry (PIV), Ultrasound Imaging Velocimetry (UIV), Colour Doppler Ultrasound (CDUS), and Planar Laser Induced Fluorescence (PLIF). Of these methods, the ultrasound techniques can also be used in-vivo, to provide realistic boundary conditions to in-vitro experiments or numerical simulations. In the reviewed work, experimental modelling is mainly used to support computational models, but also in some cases as a tool on its own. It is concluded that, to further advance the utility of computational modelling in vascular access research, a rigorous verification and validation procedure should be adopted. Experimental modelling can play an important role in both in-vitro The final publication is available at Springer via http://dx.doi.org/10.1007/s13239-017-0311-4 2 S. Drost et al.validation, and the quantification of the accuracy, uncertainty, and reproducibility of in-vivo measurement methods.

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Modeling hemodynamics in intracranial aneurysms: Comparing accuracy of CFD solvers based on finite element and finite volume schemes

Botti

Paliwal

Conti

et al. 2018

Numer Methods Biomed Eng

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Image-based computational fluid dynamics (CFD) has shown potential to aid in the clinical management of intracranial aneurysms, but its adoption in the clinical practice has been missing, partially because of lack of accuracy assessment and sensitivity analysis. To numerically solve the flow-governing equations, CFD solvers generally rely on 2 spatial discretization schemes: finite volume (FV) and finite element (FE). Since increasingly accurate numerical solutions are obtained by different means, accuracies and computational costs of FV and FE formulations cannot be compared directly. To this end, in this study, we benchmark 2 representative CFD solvers in simulating flow in a patient-specific intracranial aneurysm model: (1) ANSYS Fluent, a commercial FV-based solver, and (2) VMTKLab multidGetto, a discontinuous Galerkin (dG) FE-based solver. The FV solver's accuracy is improved by increasing the spatial mesh resolution (134k, 1.1m, 8.6m, and 68.5m tetrahedral element meshes). The dGFE solver accuracy is increased by increasing the degree of polynomials (first, second, third, and fourth degree) on the base 134k tetrahedral element mesh. Solutions from best FV and dGFE approximations are used as baseline for error quantification. On average, velocity errors for second-best approximations are approximately 1 cm/s for a [0,125] cm/s velocity magnitude field. Results show that high-order dGFE provides better accuracy per degree of freedom but worse accuracy per Jacobian nonzero entry as compared with FV. Cross-comparison of velocity errors demonstrates asymptotic convergence of both solvers to the same numerical solution. Nevertheless, the discrepancy between underresolved velocity fields suggests that mesh independence is reached following different paths.

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Numerical Evaluation and Experimental Validation of Pressure Drops Across a Patient-Specific Model of Vascular Access for Hemodialysis

Cited by 22 publications

References 31 publications

Suppressing unsteady flow in arterio-venous fistulae

Suppressing unsteady flow in arterio-venous fistulae

Review of Experimental Modelling in Vascular Access for Hemodialysis

Modeling hemodynamics in intracranial aneurysms: Comparing accuracy of CFD solvers based on finite element and finite volume schemes

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