Sh. Kute et Da. Vorp, The effect of proximal artery flow on the hemodynamics at the distal anastomosis of a vascular bypass graft: Computational study, J BIOMECH E, 123(3), 2001, pp. 277-283
Citations number
41
Categorie Soggetti
Multidisciplinary
Journal title
JOURNAL OF BIOMECHANICAL ENGINEERING-TRANSACTIONS OF THE ASME
The formation of distal anastomotic intimal hyperplasia (IH), one common mo
de of bypass graft failure, has been shown To occur in the areas of disturb
ed flow particular to this sire. The nature of the flow in the segment of a
rtery proximal to the distal anastomosis varies from case to case depending
on the clinical situation presented A partial stenosis of a bypassed arter
ial segment may allow residual prograde flow through the proximal artery en
tering the distal anastomosis of the graft. A complete stenosis may allow f
or zero flow in the proximal artery segment or retrograde flow due to the p
resence of small collateral vessels upstream. Although a number of investig
ations an the hemodynamics at the distal anastomosis of an end-to-side bypa
ss graft have been conducted, there has not been a uniform treatment of the
proximal artery flow condition. As a result, direct comparison of results
from study to study may nor be appropriate. The purpose of this work was to
perform a three-dimensional computational investigation to study the effec
t of the proximal artery flow condition (i.e., prograde, zero, and retrogra
de flow) on the hemodynamics at the distal end-to-side anastomosis. We used
the finite volume method to solve the full Navier-Stokes equations for ste
ady flow through an idealized geometry of the distal anastomosis. We calcul
ated the flow field and local wall shear stress (WSS) and WSS gradient (WSS
G) everywhere in the domain, We also calculated the severity parameter (SP)
, a quantification of hemodynamic variation, at the anastomosis. Our model
showed a marked difference in both the magnitude and spatial distribution o
f WSS and WSSG. For example, the maximum WSS magnitude on the floor of the
artery proximal to the anastomosis for the prograde and zero flow cases is
1.8 and 3.9 dynes/cm(2), respectively, while it is increased to 10.3 dynes/
cm(2) in the retrograde flow case, Similarly: the maximum value of WSSG mag
nitude on the floor of the artery proximal to the anastomosis for the progr
ade pou case is 4.9 dynes/cm(3), while it is increased to 13.6 and 24.2 dyn
es/cm(3), respectively, in the zero and retrograde flow cases. The value of
SP is highest for the retrograde flow case (13.7 dynes/cm(3)) and 8.1 and
12.1 percent lower than this for the prograde (12.6 dynes/cm(3)) and zero (
12.0 dynes/cm(3)) flow cases, respectively. Our model results suggest that
the flow condition in the proximal artery is an important determinant of th
e hemodynamics at the distal anastomosis of end-to-side vascular bypass gra
fts. Because hemodynamic forces affect the response of vascular endothelial
cells, the flow situation in the proximal artery may affect IH formation a
nd, therefore, long-term graft patency. Since surgeons have some control ov
er the flow: condition in the proximal artery, results from this study coul
d help determine which flow condition is clinically optimal.