Flow separation in the renal arteries.

Sabbah, Hani N.; Hawkins, Earl T.; Stein, Paul D.

doi:10.1161/01.atv.4.1.28

Cited by 19 publications

(4 citation statements)

References 30 publications

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“…Previously reported in vivo flow measurements in aorta and renal arteries (Sabbah et al 1984) were used to determine the appropriate boundary conditions for the CFD analysis. To ensure that the flow entering the renal arteries was fully developed, a parabolic streamwise velocity profile (Equation (1)) was implemented as an inlet boundary condition.…”

Section: Resultsmentioning

confidence: 99%

Spiral blood flow in aorta–renal bifurcation models

Javadzadegan

Simmons

Barber

2015

Computer Methods in Biomechanics and Biomedical Engineering

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The presence of a spiral arterial blood flow pattern in humans has been widely accepted. It is believed that this spiral component of the blood flow alters arterial haemodynamics in both positive and negative ways. The purpose of this study was to determine the effect of spiral flow on haemodynamic changes in aorta-renal bifurcations. In this regard, a computational fluid dynamics analysis of pulsatile blood flow was performed in two idealised models of aorta-renal bifurcations with and without flow diverter. The results show that the spirality effect causes a substantial variation in blood velocity distribution, while causing only slight changes in fluid shear stress patterns. The dominant observed effect of spiral flow is on turbulent kinetic energy and flow recirculation zones. As spiral flow intensity increases, the rate of turbulent kinetic energy production decreases, reducing the region of potential damage to red blood cells and endothelial cells. Furthermore, the recirculation zones which form on the cranial sides of the aorta and renal artery shrink in size in the presence of spirality effect; this may lower the rate of atherosclerosis development and progression in the aorta-renal bifurcation. These results indicate that the spiral nature of blood flow has atheroprotective effects in renal arteries and should be taken into consideration in analyses of the aorta and renal arteries.

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Section: Resultsmentioning

confidence: 99%

Spiral blood flow in aorta–renal bifurcation models

Javadzadegan

Simmons

Barber

2015

Computer Methods in Biomechanics and Biomedical Engineering

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“…24 This phenomenon might be the result of a physiologic flow reversal, as it is seen in some pulsatile flow studies. 31 Figure 3 shows the time dependent study for the physiological and the most severe pathological condition. The pressure variation shows the dependence of the position in the arterial tree and follows a gradual proximal to distal distribution.…”

Section: Resultsmentioning

confidence: 99%

Hemodynamic Modeling of the Intrarenal Circulation

et al. 2013

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Three dimensional, time dependent numerical simulations of healthy and pathological conditions in a model kidney were performed. Blood flow in a kidney is not commonly investigated by computational approach, in contrast for example, to the flow in a heart. The flow in a kidney is characterized by relatively small Reynolds number (100 < Re < 0.01-laminar regime). The presented results give insight into the structure of such flow, which is hard to measure in vivo. The simulations have suggested that venous thrombosis is more likely than arterial thrombosis-higher shear rate observed. The obtained maximum velocity, as a result of the simulations, agrees with the observed in vivo measurements. The time dependent simulations show separation regimes present in the vicinity of the maximum pressure value. The pathological constriction introduced to the arterial geometry leads to the changes in separation structures. The constriction of a single vessel affects flow in the whole kidney. Pathology results in different flow rate values in healthy and affected branches, as well as, different pulsate cycle characteristic for the whole system.

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“…At angles close to perpendicular or obtuse angles, the curvature of the streamlines increases, causing backflow and vorticity, which lowers pressure [16] . This turbulent flow increases the turbulent kinetic energy (TKE), which can impair endothelial function, resulting in a higher risk of atherosclerosis development in the region of renal artery branching [17] . It has been demonstrated that disturbed flow might be associated with serious negative effects such as atherosclerosis [18] or aneurysm [19] .…”

Section: Introductionmentioning

confidence: 99%

Optimal Renal Artery-Aorta Angulation Revealed by Flow Simulation

Csonka

Nagy

Stella

et al. 2023

Kidney Blood Press Res

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Introduction In blood circulation, the vessel branching angle may have hemodynamic consequences. We hypothesized that there is a hemodynamically optimal range for the renal artery branching angle. Methods Posttransplant kinetics of eGFR (estimated glomerular filtration rate) data were analyzed regarding the donor and implant sides (right-to-right, left-to-right position) (n=46). The renal artery branching angle from the aorta of a randomly selected population was measured using an X-ray angiogram (n=44). Computational fluid dynamics simulation was used to elucidate the hemodynamic effects of angulation. Results, and Discussion Renal transplant patients receiving a right donor kidney to the right side showed faster adaptation and higher eGFR values than those receiving a left donor kidney to the right side (eGFR: 65±7 vs 56±6 ml/min/1.73 m2; P <0.01). The average left side branching angle was 78°, and the right side was 66°. Simulation results showed that pressure, volume flow and velocity were relatively constant between 58° and 88°, indicating that this range is optimal for the kidneys. The turbulent kinetic energy shows no significant change between 58° and 78°. Conclusion The results suggest that there is an optimal range for renal artery branching angle from the aorta where hemodynamic vulnerability caused by the degree of angulation is the lowest, which should be considered during kidney transplantations.

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Flow separation in the renal arteries.

Cited by 19 publications

References 30 publications

Spiral blood flow in aorta–renal bifurcation models

Spiral blood flow in aorta–renal bifurcation models

Hemodynamic Modeling of the Intrarenal Circulation

Optimal Renal Artery-Aorta Angulation Revealed by Flow Simulation

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