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. 2011 Apr;44(2):89-98.
doi: 10.5090/kjtcs.2011.44.2.89. Epub 2011 Apr 14.

Influences of Geometric Configurations of Bypass Grafts on Hemodynamics in End-to-Side Anastomosis

Jae-Sung Choi  1 , Sung Chul Hong, Hyuck Moon Kwon, Sang-Ho Suh, Jeong Sang Lee
Affiliations

Influences of Geometric Configurations of Bypass Grafts on Hemodynamics in End-to-Side Anastomosis

Jae-Sung Choi et al. Korean J Thorac Cardiovasc Surg. 2011 Apr.

Abstract

Background: Although considerable efforts have been made to improve the graft patency in coronary artery bypass surgery, the role of biomechanical factors remains underrecognized. The aim of this study is to investigate the influences of geometric configurations of the bypass graft on hemodynamic characteristics in relation to anastomosis.

Materials and methods: The Numerical analysis focuses on understanding the flow patterns for different values of inlet and distal diameters and graft angles. The Blood flow field is treated as a two-dimensional incompressible laminar flow. A finite volume method is adopted for discretization of the governing equations. The Carreau model is employed as a constitutive equation for blood. In an attempt to obtain the optimal aorto-coronary bypass conditions, the blood flow characteristics are analyzed using in vitro models of the end-to-side anastomotic angles of 45°, 60° and 90°. To find the optimal graft configurations, the mass flow rates at the outlets of the four models are compared quantitatively.

Results: This study finds that Model 3, whose bypass diameter is the same as the inlet diameter of the stenosed coronary artery, delivers the largest amount of blood and the least pressure drop along the arteries.

Conclusion: Biomechanical factors are speculated to contribute to the graft patency in coronary artery bypass grafting.

Keywords: Anastomosis, surgery; Computer simulation; Coronary artery bypass; Hemodynamics.

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Figures

Fig. 1
Fig. 1
Geometric configuration of end-to-side coronary artery bypass grafting (m=Mass flow rate; d=Diameter of bypass graft; D=Diameter of coronary artery).
Fig. 2
Fig. 2
Geometric mesh of the model for numerical analysis.
Fig. 3
Fig. 3
Pressure variations along the coronary arteries and bypass grafts for an anastomotic angle of 45°.
Fig. 4
Fig. 4
Pressure variations along the coronary arteries and bypass grafts for an anastomotic angle of 60°.
Fig. 5
Fig. 5
Pressure variations along the coronary arteries and bypass grafts for an anastomotic angle of 90°.
Fig. 6
Fig. 6
Wall shear stress distributions along the outer wall of the bypass grafts for different anastomotic angles.
Fig. 7
Fig. 7
Wall shear stress distributions along the outer wall of the stenosed coronary artery for different anastomotic angles.
Fig. 8
Fig. 8
Wall shear stress distributions along the inner wall of the bypass grafts for different anastomotic angles.
See this image and copyright information in PMC

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