Biomechanics of Coronary Artery and Bypass Graft Disease: Potential New Approaches

John, Lindsay C.H.

doi:10.1016/j.athoracsur.2008.07.023

Cited by 42 publications

(30 citation statements)

References 65 publications

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“…Generally, the wall shear stress is lowest along the inner curvature and it becomes greater as the curvature increases [9]. This is partly in line with the results of this study.…”

Section: Discussionsupporting

confidence: 90%

“…According to a recent review [9], the relevant biomechanical factors predisposing to host coronary artery and bypass graft disease are classified into primary and secondary factors. The primary biomechanical factors are (1) low-wall shear stress or highly oscillatory wall shear stress and (2) high-wall mechanical stress or strain.…”

Section: Discussionmentioning

confidence: 99%

“…Low-wall shear stress and high-wall mechanical stress/strain are the primary biomechanical factors predisposing a patient to coronary bypass graft disease [9]. Various factors including vessel geometry and coronary artery movement have been identified as directly affecting the primary biomechanical factors [10-12].…”

Section: Introductionmentioning

confidence: 99%

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

Choi

Hong

Kwon

et al. 2011

Korean J Thorac Cardiovasc Surg

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BackgroundAlthough 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 MethodsThe 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.ResultsThis 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.ConclusionBiomechanical factors are speculated to contribute to the graft patency in coronary artery bypass grafting.

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“…Generally, the wall shear stress is lowest along the inner curvature and it becomes greater as the curvature increases [9]. This is partly in line with the results of this study.…”

Section: Discussionsupporting

confidence: 90%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

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

Choi

Hong

Kwon

et al. 2011

Korean J Thorac Cardiovasc Surg

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show abstract

“…Besides these, vessel geometry and wall structure are the other mechanic factors involved. 13) Low shear stress is mostly encountered in bending and bifurcating zones of the arteries. 14) Endothelial cells become exposed to multiple factors that would result in progression of atherosclerosis and this effect triggers and accelerates inflammatory changes in the vascular wall.…”

Section: Discussionmentioning

confidence: 99%

Should Right Coronary Bypass Grafts Be Anastomosed Proximal or Distal to the Crux? A Comparison of Graft Patencies

Aksüt

Köksal

Kocamaz

et al. 2012

Ann Thorac Cardiovasc Surg

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Aim: Late occlusion of bypass grafts is one of the main issues associated with long-term survival after coronary artery bypass grafting (CABG) surgery. Left coronary system is generally revascularized using arterial conduits, whereas saphenous venous grafts are used for right coronary system. We investigated the prognostic factors that are related to the patency and risk of occlusion of saphenous venous grafts used for revascularization of diseased right coronary arteries. Patients and Method: 92 patients who underwent CABG operation including a right coronary artery (RCA) bypass using saphenous venous graft (SVG) between January 2003 and July 2010 were evaluated retrospectively. Mean time of follow up was 66.9 ± 27.2 months (range 104-13 months). Grafts patencies were investigated using coronary angiography, and associated risk factors for mortality and morbidity were determined during the mid-term and long-term follow up. During the data collection phase, a significant association was noticed between patency of right coronary bypass grafts and site of distal anastomoses on RCA. Thus, patients were divided into two groups, according to the site of anastomosis. Right coronary anastomoses were performed either proximal (Group A, n = 44) or distal (Group B, n = 46) to the crux of the RCA (PDA). Results: Patency rates were similar in-group A (50% occluded and 50% patent) whereas patency rates were significantly higher in-group B (occluded 16.7%, patent 83.3%, p = 0.001). Mean age was significantly higher in-group A compared to Group B (p <0.05); however, there was no statistically significant difference between the two groups with regard to risk factors associated with cardiovascular disease (p >0.05). Also, mean diameter of the target vessel was significantly higher in-group A (p <0.01). Conclusion: Based on the results of our study we suggest that even though an appropriate segment for anastomosis is available proximal to the crux of the RCA, right posterior descending artery (PDA) should be preferred for revascularization when RCA is the target vessel in CABG.

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“…Hemodynamics has been widely acknowledged to have significant influence on the arterial diseases. Flow disturbances are confirmed to be related to the intimal hyperplasia and arterial thrombosis [8, 9]. Wall shear stress (WSS) may play an important role in graft patency after CABG [10].…”

Section: Introductionmentioning

confidence: 99%

Impact of Competitive Flow on Hemodynamics in Coronary Surgery: Numerical Study of ITA-LAD Model

Ding

Liu²,

Wang³

et al. 2012

Computational and Mathematical Methods in Medicine

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Competitive flow from native coronary artery is considered as a major factor in the failure of the coronary artery bypass grafts. However, the physiological effects are not very clear. The aim is to research the impact of competitive flow caused by different left anterior descending (LAD) artery stenosis degrees on hemodynamics in internal thoracic artery (ITA) bypass graft. An idealized ITA-LAD model was built in CAD tools. The degree of the competitive flow was divided into five classes according to different LAD stenosis degrees: higher (no stenosis), secondary (30% stenosis), reduced (50% stenosis), lower (75% stenosis) and no competitive flow (fully stenosis). Finite volume method was employed for the numerical simulation. The flow velocity distributions, wall shear stress and oscillatory shear index were analyzed. Results showed that higher competitive flow in the bypass graft would produce unbeneficial wall shear stress distribution associating with endothelial dysfunction and subsequent graft failure. The coronary bypass graft surgery was preferred to be carried out when the LAD stenosis was higher than 75%.

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Biomechanics of Coronary Artery and Bypass Graft Disease: Potential New Approaches

Cited by 42 publications

References 65 publications

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

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

Should Right Coronary Bypass Grafts Be Anastomosed Proximal or Distal to the Crux? A Comparison of Graft Patencies

Impact of Competitive Flow on Hemodynamics in Coronary Surgery: Numerical Study of ITA-LAD Model

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