A numerical study of blood flow in coronary artery bypass graft side-to-side anastomoses.
OBJECTIVE
When sequential grafts are used in multivessel coronary artery bypass grafting, the graft first supplies blood to one or more coronary arteries via a side-to-side anastomosis. We studied hemodynamics in idealized models of "parallel" and "diamond" side-to-side anastomoses, identifying features that might promote restenosis.


METHODS
Blood flow was computed in three representative anastomosis configurations: parallel side-to-side, diamond side-to-side, and end-to-side. We compared configurations and the effect of host-graft diameter ratio.


RESULTS
Hemodynamic patterns depended strongly on anastomosis geometry and graft/host diameter ratio. In the distal graft, the diamond configuration had large areas of low wall shear stress (WSS) and high spatial WSS gradients. In the proximal graft the unfavorable WSS patterns were comparable for all models, while the distal portion of the host artery the diamond model was best. Models with smaller host arteries had smaller regions of low WSS.


CONCLUSIONS
The parallel configuration was preferred over the diamond for maintaining graft patency, while the diamond configuration appeared best for maintaining host artery patency. Since graft patency is critical, parallel configurations seem hemodynamically advantageous. Larger graft/host ratios have better hemodynamic performance than smaller ones.
Department of Mechanical and Industrial Engineering, University of Toronto, Ontario, Canada.
Michael
M
Bonert
Jerry G
JG
Myers
Stephen
S
Fremes
James
J
Williams
C Ross
CR
Ethier
D000714:Anastomosis, Surgical / Q000295:instrumentation / Q000379:methods; D001158:Arteries / Q000503:physiopathology* / Q000601:surgery*; D001783:Blood Flow Velocity; D001807:Blood Vessel Prosthesis; D003198:Computer Simulation; D001026:Coronary Artery Bypass / Q000379:methods*; D019544:Equipment Failure Analysis / Q000379:methods; D020342:Finite Element Analysis; D006439:Hemodynamics; D006801:Humans; D008955:Models, Cardiovascular; D012680:Sensitivity and Specificity; D013314:Stress, Mechanical; D017539:Tunica Intima / Q000503:physiopathology