Human saphenous vein coronary artery bypass graft morphology, geometry and hemodynamics.
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.
Leask
Richard L
RL
Department of Chemical Engineering, McGill University, Montreal, Quebec. richard.leask@mcgill.ca
Butany
Jagdish
J
Johnston
K Wayne
KW
Ethier
C Ross
CR
Ojha
Matadial
M
D000368:Aged; D001783:Blood Flow Velocity; D001794:Blood Pressure; D002102:Cadaver; D001026:Coronary Artery Bypass / Q000379:methods*; D003331:Coronary Vessels / Q000473:pathology / Q000503:physiopathology* / Q000601:surgery*; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D008953:Models, Anatomic; D008955:Models, Cardiovascular; D012501:Saphenous Vein / Q000473:pathology / Q000503:physiopathology* / Q000637:transplantation*; D033081:Shear Strength