Numerical and experimental models of post-operative realistic flows in stenosed coronary bypasses

Bertolotti, Christine; Deplano, Valérie; Fuseri, Jean; Dupouy, Patrick

doi:10.1016/s0021-9290(01)00027-6

Cited by 73 publications

(56 citation statements)

References 42 publications

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“…The boundary conditions for the simulation are: 1. At the inlet sections of coronary and graft, longitudinal velocities with blunt or flat profiles are imposed according to the physiological flowrates measured in a human coronary bypass a few days after CABG surgery [7]. The extended graft and coronary are allowed for the flat inlet velocity profiles to fully develop.…”

Section: Simulating Conditions and Methodsmentioning

confidence: 99%

“…excessive tissue overgrowth and renewed plaque formation) tend to develop in the vicinity of distal anastomosis and result in early graft failure [2][3][4][5][6]. IH has been extensively reviewed, and clinical observations indicate that IH predominantly occurs in four regions of anastomosis [7]: the heel, the toe, the suture-line, and the floor opposite the anastomosis (Figure 1). Many factors influence the initiation and development of IH and restenosis, for example a physiological and biomechanical mismatch between the graft and coronary artery, mural injury, local hemodynamics, etc.…”

Section: Introductionmentioning

confidence: 99%

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Numerical Simulation of Physiological Blood Flow in 2-way Coronary Artery Bypass Grafts

Qiao

Liu

Li³

et al. 2005

J Biol Phys

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Abstract. The Coronary Artery Bypass Graft (CABG) yields excellent results and remains the modern standard of care for treatment of occlusive disease in the cardiovascular system. However, the development of anastomotic Intimal Hyperplasia (IH) and restenosis can compromise the mediumand-long term effects of the CABG. This problem can be correlated with the geometric configuration and hemodynamics of the bypass graft. A novel geometric configuration was proposed for the CABG with two symmetrically implanted grafts for the purpose of improving the hemodynamics. Physiological blood flows in two models of bypass grafts were simulated using numerical methods. One model was for the conventional bypass configuration with a single graft (1-way model); the other model was for the proposed bypass configuration with two grafts (2-way model). The temporal and spatial distributions of hemodynamics, such as flow patterns and Wall Shear Stress (WSS) in the vicinity of the distal anastomoses, were analyzed and compared. Calculation results showed that the 2-way model possessed favorable hemodynamics with uniform longitudinal flow patterns and WSS distributions, which could decrease the probability of restenosis and improve the effect of the surgical treatment. Concerning the limitations of the 2-way bypass grafts, it is necessary to perform animal experiments to verify the viability of this novel idea for the CABG.

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Section: Simulating Conditions and Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of Physiological Blood Flow in 2-way Coronary Artery Bypass Grafts

Qiao

Liu

Li³

et al. 2005

J Biol Phys

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“…displacement of the flow channel and solid must be compatible [11], traction must be at equilibrium [12], and fluid obeys the no-slip condition [13]:…”

Section: Boundary and Interface Conditionsmentioning

confidence: 99%

“…Numerical simulation based on Finite Element method was carried out. Bertolotti et al [13] studied three-dimensional transient flows of fluid through coronary arterial bypass grafting using the inflow rates obtained from in vivo measurements in patients who had gone through coronary bypass surgery a few days before. The interplay between the fluid flows and the graft has been investigated.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of Turbulent Blood Flow in the System of Coronary Arteries with Stenosis

Kaewbumrung¹,

Wiwatanapataphee²,

Orankitjaroen³

et al. 2017

J Biom Biostat

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In this paper, we propose a mathematical model of turbulence flow of fluid through a deformable channel to study the pulsatile blood flow in the coronary system with arterial stenosis. Blood is assumed to be an incompressible nonNewtonian fluid and its motion is considered as turbulent and modelled by the mass and momentum conservations with turbulent mixing energy and specific dissipation rate. The mechanical deformation of the arterial wall is modelled by a hyperelastic differential equation. The pulsatile behaviour during each heartbeat is assigned on the entrance and exit boundaries. Numerical simulation based on the Finite Element method for the solution of arterial wall deformation, and the Arbitrary Lagrangian Eulerian Finite Volume method for the turbulence fluid-flow solution is used to investigate the effect of stenosis severity at the proximal part of the left anterior descending artery on the blood velocity, the pressure distribution and the wall shear stresses along the flow direction.

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“…However, only a few of these studies have in vitro physical models to verify their numerical models [15][16][17][18][19][20][21][22]. The physical model of CABG is very valuable to assess the flow fields parameters practically.…”

Section: Introductionmentioning

confidence: 99%

Numerical and Physical Models of Distal Anastomosis in Coronary Artery Bypass Grafting

Long¹,

Yang²

2017

Proceedings of the 2016 International Conference on Biological Engineering and Pharmacy (BEP 2016)

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Abstract-The progressive anastomotic intimal hyperplasia has been considered as a major failure reason for coronary artery bypass grafting (CABG), which is associated with the abnormality of the hemodynamic conditions. We designed a set of plexiglass models which can serve as in vitro cells or tissue culture bioreactors, also serve as mechanical flow chambers in a physical perfusion system of CABG. The models of distal anastomosis with different angles were made of plexiglass material. The anastomotic angles α in three models are 60°, 30° and 15°, respectively. The numerical simulation models, reproducing from these physical models, were set up using a computer fluid dynamic (CFD) software. First, the numerical results showed that in the model with α=60° there is a high velocity characteristic on the floor of the host artery opposite the graft orifice, where significant intimal thickening is likely to occur. Decreasing α, the peak velocity will move to the outlet of host artery. Second, the stagnant flow region depends directly on the distance D (The distance from the heel of the graft to the center of stenosed site), the larger is the value of D, and the longer is the stagnant region. We also found the residual flow which is harmful to the orifice region and the distal portion of anastomotic gradually became more slender as severity of the stenosis increased. The results suggest that anastomotic angle and stenosed site are very important factors for preoperative investigation. A smaller α can eliminate the stagnation and decrease the risk of intimal thickening at the anastomotic junction, while a shorter D can decrease stagnant region. The results also showed that our perfusion system and the physical models are feasible for CABG studies.

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Numerical and experimental models of post-operative realistic flows in stenosed coronary bypasses

Cited by 73 publications

References 42 publications

Numerical Simulation of Physiological Blood Flow in 2-way Coronary Artery Bypass Grafts

Numerical Simulation of Physiological Blood Flow in 2-way Coronary Artery Bypass Grafts

Numerical Simulation of Turbulent Blood Flow in the System of Coronary Arteries with Stenosis

Numerical and Physical Models of Distal Anastomosis in Coronary Artery Bypass Grafting

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