Related Experiment Video
Updated: Aug 18, 2026
Synergizing Antegrade Endoscopic with Bridging Vein Harvesting for Improvement of Great Saphenous Vein Graft Quality from the Lower Leg
Published on: November 19, 2019
Human saphenous vein coronary artery bypass graft morphology, geometry and hemodynamics
Richard L Leask1, Jagdish Butany, K Wayne Johnston
1Department of Chemical Engineering, McGill University, Montreal, Quebec. richard.leask@mcgill.ca
Insights
Coronary artery bypass graft (CABG) failure is linked to graft hemodynamics. Specific graft geometry, particularly at the hood, creates high wall shear stress, promoting intimal hyperplasia and potential graft failure.
Area of Science:
- Cardiovascular Surgery
- Biomedical Engineering
- Medical Imaging
Background:
- Coronary artery bypass graft (CABG) failure is a significant clinical challenge.
- Graft hemodynamics, especially wall shear stress, are implicated in CABG failure.
- Understanding graft morphology and its impact on hemodynamics is crucial for improving graft patency.
Purpose of the Study:
- To characterize the morphology and geometry of human saphenous vein CABGs.
- To investigate wall shear stress patterns within these grafts.
- To identify geometric features associated with intimal hyperplasia and potential graft failure.
Main Methods:
- Digital light microscopy was used to measure intimal thickness (IT) in 49 human saphenous vein CABGs.
- Anatomical corrosion casting was employed to replicate graft geometry.
- Flow models were created from casts to evaluate hemodynamics under steady and pulsatile flow conditions.
Main Results:
- Saphenous vein CABGs showed greatest intimal thickness at the hood and suture sites of the distal anastomosis after two months in situ.
- Graft casts revealed characteristic indentations and sharp curvatures, particularly at the hood.
- Flow models demonstrated significant increases in wall shear rate at the hood, proximal to the toe, correlating with local geometry.
Conclusions:
- The local geometry of the CABG hood significantly influences wall shear stress distribution.
- High spatial gradients in wall shear stress at the hood are a likely contributor to intimal hyperplasia.
- These findings highlight the importance of graft geometry in CABG failure mechanisms.
Abstract:
Coronary artery bypass graft (CABG) failure has been linked to graft hemodynamics, in particular wall shear stress. This study characterizes the morphology, geometry and wall shear stress patterns in human CABGs. The intimal thickness (IT) in 49 human saphenous vein CABGs was measured by digital light microscopy. The geometry of six saphenous vein CABGs was replicated by post-mortem infusion of Batson's #17 anatomical corrosion casting compound. Graft hemodynamics were evaluated in two flow models, fabricated from the casts, under steady (Re = 110) and pulsatile flow (Re = 110, alpha = 2) conditions. Saphenous vein CABGs in situ for more than 2 months had, on average, the greatest IT on the hood and suture sites of the distal anastomosis. Floor thickening was highly variable and significantly less than IT at the hood, suture site and graft body. All casts showed an indentation along the floor and 5/6 casts displayed a sharp local curvature on the hood. In both flow models, a large increase in wall shear rate occurred on the hood, just proximal to the toe. The local geometry of the hood created this large spatial gradient in wall shear stress which is a likely factor in hood intimal hyperplasia.
