CABG MODELS FLOW SIMULATION STUDY ON THE EFFECTS OF VALVE REMNANTS IN THE VENOUS GRAFT

2010 ◽  
Vol 10 (04) ◽  
pp. 593-609 ◽  
Author(s):  
FOAD KABINEJADIAN ◽  
LEOK POH CHUA ◽  
DHANJOO N. GHISTA ◽  
YONG SENG TAN
Keyword(s):  
Blood Flow ◽  
Artery Bypass ◽  
Atherosclerotic Lesion ◽  
Flow Simulation ◽  
Coronary Artery Bypass Grafts ◽  
Vein Grafts ◽  
Venous Valves ◽  
Surface Irregularities ◽  
Early Atherosclerotic Lesion ◽  
Blood Flow Patterns

Venous valves and sinuses are frequently observed in vein grafts in the coronary artery bypass grafts (CABG). However, from the biomedical engineering viewpoint, vein grafts are always assumed as smooth tubes in the existing simulations, and no effort has been made to investigate the effects of jaggedness of the graft inner wall due to the valve cusps remnants and valve sinus (in case of valve-stripped saphenous vein (SV) grafts) on the blood flow patterns and hemodynamic parameters (HPs). In this paper, the effects of the inner surface irregularities of a vein graft on the blood flow is investigated in the graft as well as in the distal anastomotic region, with a more realistic geometry of valve-stripped SV, by means of numerical simulation of pulsatile, Newtonian blood flow. The simulation results demonstrate that the valve remnants and sinuses cause disturbances in the flow field within the graft (due to vortices formation within the valve sinuses) and undesirable distribution of HPs, which can result in early atherosclerotic lesion development in the graft.

scholarly journals Biomechanics and Mechanobiology of Saphenous Vein Grafts

2018 ◽  
Vol 140 (2) ◽  
Author(s):  
Keith J. Gooch ◽  
Michael S. Firstenberg ◽  
Brittany S. Shrefler ◽  
Benjamin W. Scandling
Keyword(s):  
Artery Bypass ◽  
Surgical Techniques ◽  
Graft Patency ◽  
Coronary Artery Bypass Grafts ◽  
Mechanical Trauma ◽  
Mechanical Environment ◽  
Endoscopic Techniques ◽  
Vein Grafts ◽  
Arterial Circulation ◽  
Vein Graft Failure

Within several weeks of use as coronary artery bypass grafts (CABG), saphenous veins (SV) exhibit significant intimal hyperplasia (IH). IH predisposes vessels to thrombosis and atherosclerosis, the two major modes of vein graft failure. The fact that SV do not develop significant IH in their native venous environment coupled with the rapidity with which they develop IH following grafting into the arterial circulation suggests that factors associated with the isolation and preparation of SV and/or differences between the venous and arterial environments contribute to disease progression. There is strong evidence suggesting that mechanical trauma associated with traditional techniques of SV preparation can significantly damage the vessel and might potentially reduce graft patency though modern surgical techniques reduces these injuries. In contrast, it seems possible that modern surgical technique, specifically endoscopic vein harvest, might introduce other mechanical trauma that could subtly injure the vein and perhaps contribute to the reduced patency observed in veins harvested using endoscopic techniques. Aspects of the arterial mechanical environment influence remodeling of SV grafted into the arterial circulation. Increased pressure likely leads to thickening of the medial wall but its role in IH is less clear. Changes in fluid flow, including increased average wall shear stress, may reduce IH while disturbed flow likely increase IH. Nonmechanical stimuli, such as exposure to arterial levels of oxygen, may also have a significant but not widely recognized role in IH. Several potentially promising approaches to alter the mechanical environment to improve graft patency are including extravascular supports or altered graft geometries are covered.

Extensive Myocardial Blood Flow Distribution Through Individual Coronary Artery Bypass Grafts

CHEST Journal ◽  
1980 ◽  
Vol 77 (1) ◽  
pp. 17-23 ◽  
Author(s):  
Albert J. Kolibash ◽  
Richard P. Lewis ◽  
John S. Goodenow ◽  
Charles A. Bush ◽  
Marc R. Tetalman
Keyword(s):  
Blood Flow ◽  
Coronary Artery ◽  
Myocardial Blood Flow ◽  
Coronary Artery Bypass ◽  
Artery Bypass ◽  
Flow Distribution ◽  
Coronary Artery Bypass Grafts ◽  
Blood Flow Distribution ◽  
Bypass Grafts
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