Numerical modelling of simulated blood flow in idealized composite arterial coronary grafts: Transient flow

Abstract In composite arterial coronary grafts (CACGs), transport phenomena and geometry may considerably alter blood flow dynamics. CACGs aim at revascularizing pathological arteries according to the human anatomy. However, the exact mechanisms causing the failure of coronary bypass grafting are no...

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Bibliographic Details
Published in:Journal of biomechanics 2008-01, Vol.41 (1), p.25-39
Main Authors: Politis, A.K, Stavropoulos, G.P, Christolis, M.N, Panagopoulos, P.G, Vlachos, N.S, Markatos, N.C
Format: Article
Language:English
Subjects:
Algorithms
Atherosclerosis
Blood
Blood Flow Velocity - physiology
Cardiovascular disease
CFD
Composite arterial coronary grafts
Computer Simulation
Coronary Artery Bypass
Coronary artery disease
Coronary Circulation - physiology
Coronary Restenosis - physiopathology
Coronary Stenosis - physiopathology
Coronary vessels
Diastole - physiology
Endothelium
Hemorheology
Humans
Models, Biological
Physical Medicine and Rehabilitation
Pulsatile Flow - physiology
Pulsating flow
Shear stress
Stress, Mechanical
Studies
Systole - physiology
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Summary:Abstract In composite arterial coronary grafts (CACGs), transport phenomena and geometry may considerably alter blood flow dynamics. CACGs aim at revascularizing pathological arteries according to the human anatomy. However, the exact mechanisms causing the failure of coronary bypass grafting are not yet well elucidated. In the present study, computational fluid dynamics (CFD) techniques are applied for the simulation of multi-branched CACGs under physiologically realistic inflow waveforms. The numerical solution is obtained by a finite-volume method formulated in non-orthogonal, curvilinear coordinates and a multi-grid approach. The geometrical models, consisting of idealized and rigid vessels, include the typical T- and a rather new Π-graft configuration. The stenotic effect is also investigated by comparing computational results for three different degrees of area constriction, namely 25%, 50% and 75%, as well as the case without stenosis. Different grafting distances and various inflow rate ratios are imposed, to give an insight into haemodynamical alterations of CACGs and to study the process of restenosis. The results focus on the interaction between the grafts and coronary flows in terms of spatial and temporal variations of velocity and wall shear stress (WSS) distribution. Prominent variations among the different geometries, concerning the velocity profiles and secondary flow motion, are shown. Moreover, the residual flow emerging from different degrees of area constriction shows that low and oscillating shear stresses may arise for even moderate stenotic fields.
ISSN:0021-9290
1873-2380
DOI:10.1016/j.jbiomech.2007.08.007