Numerical Investigation on the Geometrical Effects of Novel Graft Designs for Peripheral Artery Bypass Surgery

Keshmiri, Amir; Ruiz-Soler, Andres; McElroy, Michael; Kabinejadian, Foad

doi:10.1016/j.procir.2015.11.005

Cited by 15 publications

(14 citation statements)

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“…The localisation of various lesions including atherosclerosis, intimal hyperplasia and intimal thickening have been extensively studied and are related to different local haemodynamic metrics [5][6][7]21,[39][40][41] . These haemodynamic parameters can be directly derived from the flow velocity fields obtained by CFD simulations.…”

Section: Resultsmentioning

confidence: 99%

Impact of Using Conventional Inlet/Outlet Boundary Conditions on Haemodynamic Metrics in a Subject-Specific Rabbit Aorta

McElroy

Keshmiri

2017

Proc Inst Mech Eng H

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Computational fluid dynamics is a tool capable of accurately measuring metrics currently used to predict the behaviour of cardiovascular diseases. This study quantifies the impact various commonly used inlet and outlet boundary conditions have on various shear rate-based haemodynamic metrics currently used for predicting the localisation of cardiovascular diseases. Simulations are conducted on an accurately represented rabbit aorta configuration and comparison has been made against available in vivo data. The boundary conditions studied include two different inlet profiles, three outlet boundary conditions, and steady-state versus pulsatile flow cases. Large variations were found in the results, particularly when using different outlet boundary conditions, and the discrepancies were evaluated both quantitatively and qualitatively. The results clearly highlight the importance of the type of boundary condition used when simulating complex cardiovascular models. By restricting the attention to the flow within the aorta and the intercostal branches, the results suggest that prescribing transient simulation and fully developed flow at the inlet are not required. Furthermore, assuming the widely accepted low wall shear stress theory of Caro, it was found that Murray's law-based outlet boundary condition returns the most physiologically accurate results when compared to in vivo data.

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Section: Resultsmentioning

confidence: 99%

Impact of Using Conventional Inlet/Outlet Boundary Conditions on Haemodynamic Metrics in a Subject-Specific Rabbit Aorta

McElroy

Keshmiri

2017

Proc Inst Mech Eng H

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“…Higher number of ridges, however, would reduce the cross-sectional area and consequently increase the resistance against the flow. They may also result in an increase of pressure at the leading edge of the ridges, which can lead to deposition of cholesterol, calcium, cellular debris and fatty substances [46]. …”

Section: Resultsmentioning

confidence: 99%

“…In fact, in a very recent clinical investigation, Bechara [21] carried out a single-centre study on patients undergoing infrainguinal bypass using VFT’s spiral laminar flow graft against Propaten and found that the VFT’s graft had not led to higher patency rates in comparison to the conventional ePTFE grafts. This finding highlights the need for further investigation on the design and optimisation of the grafts with spiral ridges [46]. …”

Section: Discussionmentioning

confidence: 99%

Numerical Assessment of Novel Helical/Spiral Grafts with Improved Hemodynamics for Distal Graft Anastomoses

et al. 2016

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In the present work, numerical simulations were conducted for a typical end-to-side distal graft anastomosis to assess the effects of inducing secondary flow, which is believed to remove unfavourable flow environment. Simulations were carried out for four models, generated based on two main features of 'out-of-plane helicity' and 'spiral ridge' in the grafts as well as their combination. Following a qualitative comparison against in vitro data, various mean flow and hemodynamic parameters were compared and the results showed that helicity is significantly more effective in inducing swirling flow in comparison to a spiral ridge, while their combination could be even more effective. In addition, the induced swirling flow was generally found to be increasing the wall shear stress and reducing the flow stagnation and particle residence time within the anastomotic region and the host artery, which may be beneficial to the graft longevity and patency rates. Finally, a parametric study on the spiral ridge geometrical features was conducted, which showed that the ridge height and the number of spiral ridges have significant effects on inducing swirling flow, and revealed the potential of improving the efficiency of such designs.

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“…These results are in agreement with those obtained by Keshmiri et al . 12 . The above observation has an important implication on the peripheral artery bypass surgeries, since the rotation of the blood flow has been found as clockwise in the left common iliac arteries and anticlockwise in the right common iliac arteries 34, 41 .…”

Section: Discussionmentioning

confidence: 99%

Optimisation of a Novel Spiral-Inducing Bypass Graft Using Computational Fluid Dynamics

Ruiz-Soler

Kabinejadian

Slevin

et al. 2017

Sci Rep

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Graft failure is currently a major concern for medical practitioners in treating Peripheral Vascular Disease (PVD) and Coronary Artery Disease (CAD). It is now widely accepted that unfavourable haemodynamic conditions play an essential role in the formation and development of intimal hyperplasia, which is the main cause of graft failure. This paper uses Computational Fluid Dynamics (CFD) to conduct a parametric study to enhance the design and performance of a novel prosthetic graft, which utilises internal ridge(s) to induce spiral flow. This design is primarily based on the identification of the blood flow as spiral in the whole arterial system and is believed to improve the graft longevity and patency rates at distal graft anastomoses. Four different design parameters were assessed in this work and the trailing edge orientation of the ridge was identified as the most important parameter to induce physiological swirling flow, while the height of the ridge also significantly contributed to the enhanced performance of this type of graft. Building on these conclusions, an enhanced configuration of spiral graft is proposed and compared against conventional and spiral grafts to reaffirm its potential benefits.

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Numerical Investigation on the Geometrical Effects of Novel Graft Designs for Peripheral Artery Bypass Surgery

Cited by 15 publications

References 0 publications

Impact of Using Conventional Inlet/Outlet Boundary Conditions on Haemodynamic Metrics in a Subject-Specific Rabbit Aorta

Impact of Using Conventional Inlet/Outlet Boundary Conditions on Haemodynamic Metrics in a Subject-Specific Rabbit Aorta

Numerical Assessment of Novel Helical/Spiral Grafts with Improved Hemodynamics for Distal Graft Anastomoses

Optimisation of a Novel Spiral-Inducing Bypass Graft Using Computational Fluid Dynamics

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