Fluid Flow Structure in Arterial Bypass Anastomosis

Su, Chun-Jen; Lee, Denz; Tran‐Son‐Tay, Roger; Shyy, Wei

doi:10.1115/1.1934056

Cited by 16 publications

(17 citation statements)

References 26 publications

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“…CFD has also been employed to investigate anastomotic regions of bypass grafts. 4,5,25,31,38 Although these studies were motivated similarly by pathological responses observed in particular at the distal anastomosis of arterial bypass grafts, the simulations focussed at arterial blood flow; as such they did not deal with the fluid mechanics of AV connections.…”

Section: Introductionmentioning

confidence: 99%

A Numerical Tool for the Coupled Mechanical Assessment of Anastomoses of PTFE Arterio-venous Access Grafts

Ngoepe

Reddy

Kahn

et al. 2011

Cardiovasc Eng Tech

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The anastomotic angle is assumed to affect the performance of arterio-venous (AV) access grafts by altering wall shear stress (WSS) and wall tension. The objective of this study was to develop a coupled numerical tool to assess fluid and structural anastomotic mechanics of a straight upper arm access graft. 3D computational fluid dynamics (CFD) and finite element (FE) models were developed for arterial and venous anastomoses with different graft attachment angles. The fluid simulations were executed using flow velocity profiles for anastomotic inlets obtained from a whole-graft CFD model. A mesh adaptation algorithm was developed to couple CFD and FE meshes and capture fluid structure interactions. The coupling algorithm enabled transfer of blood pressure (BP) and WSS predicted with the CFD models to the FE models as loadings. The deformations induced in the FE models were used to update the CFD geometries after which BP and WSS were recalculated and the process repeated until equilibrium between fluid and solid models. Maximum BP in the vein was 181 mmHg. WSS peaked at 2.3 and 0.7 Pa and the structural wall stress reached 3.38 and 3.36 kPa in arterial and venous anastomosis. Since flow-induced wall tension has been identified as a contributor to access graft failure along with WSS, the computational tool will be useful in studying the coupled mechanics in these grafts. Initial investigations of arterial and venous anastomotic end-to-side configuration indicated a slightly better performance of the 90°configuration over 135°a rterial and 45°venous configurations.

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Section: Introductionmentioning

confidence: 99%

A Numerical Tool for the Coupled Mechanical Assessment of Anastomoses of PTFE Arterio-venous Access Grafts

Ngoepe

Reddy

Kahn

et al. 2011

Cardiovasc Eng Tech

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“…The posterior mean and covariance can be computed as (6) and (7) where is the correlation matrix computed using the training points; the th element of this matrix is computed as . is the correlation between the new point and the training points and .…”

Section: Bayesian Modelingmentioning

confidence: 99%

“…In the case of grafting, graft failure may occur due to the compliance mismatch at the junction between the native vessel and the graft [5]. In addition, there is some evidence to suggest that the geometry of the arterial bypass can significantly influence the postoperative haemodynamic environment [6], [7]. Hence, selection of an optimal shape and a suitable material for a bypass graft could play a critical role in inhibiting mechanical failure.…”

Section: Introductionmentioning

confidence: 99%

Predictive Haemodynamics in a One-Dimensional Human Carotid Artery Bifurcation. Part II: Application to Graft Design

Kolachalama¹,

Bressloff

Nair

et al. 2008

IEEE Trans. Biomed. Eng.

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Abstract-A Bayesian surrogate modeling technique is proposed that may be able to predict an optimal bypass graft configuration for patients suffering with stenosis in the internal carotid artery (ICA). At the outset, this statistical technique is considered as a means for identifying key geometric parameters influencing haemodynamics in the human carotid bifurcation. This methodology uses a design of experiments (DoE) technique to generate candidate geometries for flow analysis. A pulsatile one-dimensional Navier-Stokes solver incorporating fluid-wall interactions for a Newtonian fluid which predicts pressure and flow in the carotid bifurcation (comprising a stenosed segment in the internal carotid artery) is used for the numerical simulations. Two metrics, pressure variation factor (PVF) and maximum pressure ( ) are employed to directly compare the global and local effects, respectively, of variations in the geometry. The values of PVF and are then used to construct two Bayesian surrogate models. These models are statistically analyzed to visualize how each geometric parameter influences PVF and . Percentage of stenosis is found to influence these pressure based metrics more than any other geometric parameter. Later, we identify bypass grafts with optimal geometric and material properties which have low values of PVF on five test cases with 70%, 75%, 80%, 85%, and 90% stenosis in the ICA, respectively.

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“…Nowadays, the use of computational techniques in fluid dynamics to analyze physiological flows involving blood is an area of intensive research (Maurits et al, 2007;Pedrizzetti and Perktold, 2003;Sousa et al, 2012;Su et al, 2005). Blood flow is normally laminar but the periodic unsteadiness or pulsatile nature of the flow makes possible the transition to turbulence when the artery diameter decreases and velocities increase.…”

Section: Introductionmentioning

confidence: 99%