The formation of distal anastomotic intimal hyperplasia (IH), one common mode of bypass graft failure, has been shown to occur in the areas of disturbed flow particular to this site. The nature of the flow in the segment of artery proximal to the distal anastomosis varies from case to case depending on the clinical situation presented. A partial stenosis of a bypassed arterial segment may allow residual prograde flow through the proximal artery entering the distal anastomosis of the graft. A complete stenosis may allow for zero flow in the proximal artery segment or retrograde flow due to the presence of small collateral vessels upstream. Although a number of investigations on the hemodynamics at the distal anastomosis of an end-to-side bypass 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 not be appropriate. The purpose of this work was to perform a three-dimensional computational investigation to study the effect of the proximal artery flow condition (i.e., prograde, zero, and retrograde 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 steady flow through an idealized geometry of the distal anastomosis. We calculated the flow field and local wall shear stress (WSS) and WSS gradient (WSSG) 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 of 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/cm2, respectively, while it is increased to 10.3 dynes/cm2 in the retrograde flow case. Similarly, the maximum value of WSSG magnitude on the floor of the artery proximal to the anastomosis for the prograde flow case is 4.9 dynes/cm3, while it is increased to 13.6 and 24.2 dynes/cm3, respectively, in the zero and retrograde flow cases. The value of SP is highest for the retrograde flow case (13.7 dynes/cm3) and 8.1 and 12.1 percent lower than this for the prograde (12.6 dynes/cm3) and zero (12.0 dynes/cm3) flow cases, respectively. Our model results suggest that the flow condition in the proximal artery is an important determinant of the hemodynamics at the distal anastomosis of end-to-side vascular bypass grafts. Because hemodynamic forces affect the response of vascular endo- thelial cells, the flow situation in the proximal artery may affect IH formation and, therefore, long-term graft patency. Since surgeons have some control over the flow condition in the proximal artery, results from this study could help determine which flow condition is clinically optimal.

1.
Imparato
,
A. M.
,
Bracco
,
A.
,
Kim
,
G. F. E.
, and
Zeff
,
R. Z.
,
1972
, “
Intimal and Neointimal Fibrous Proliferation Causing Failure of Arterial Reconstruction
,”
Surgery
,
72
, pp.
1007
1017
.
2.
Nikkari
,
S. T.
, and
Clowes
,
A. W.
,
1994
, “
Restenosis After Vascular Reconstruction
,”
Ann. Med.
,
26
, pp.
95
100
.
3.
Clowes, A. W., 1995, “Pathologic Intimal Hyperplasia As a Response to Vascular Injury and Reconstruction,” in: Vascular Surgery, R. B. Rutherford, ed., 4th ed., W. B. Saunders Company, Philadelphia, pp. 285–295.
1.
Bassiouny
,
H. S.
,
White
,
S.
,
Glagov
,
S.
,
Choi
,
E.
,
Giddens
,
D. P.
, and
Zarins
,
C. K.
,
1992
, “
Anastomotic Intimal Hyperplasia: Mechanical Injury or Flow Induced
,”
J. Vasc. Surg.
,
15
, pp.
708
716
;
2.
Discussion 716–717.
1.
Logerfo
,
F.
,
Quist
,
W.
,
Nowak
,
M.
,
Crawshaw
,
H.
, and
Haudenschild
,
C.
,
1983
, “
Downstream Anastomotic Hyperplasia. A Mechanism of Failure in Dacron Arterial Grafts
,”
Ann. Surg.
,
197
, pp.
479
483
.
2.
Ojha
,
M.
,
1993
, “
Spatial and Temporal Variations of Wall Shear Stress Within an End-to-Side Arterial Anastomosis Model
,”
J. Biomech.
,
26
, pp.
1377
1388
.
3.
Ojha
,
M.
,
Ethier
,
C.
,
Johnston
,
K.
, and
Cobbold
,
R.
,
1990
, “
Steady and Pulsatile Flow Fields in an End-to-Side Arterial Anastomosis Model
,”
J. Vasc. Surg.
,
12
, pp.
747
753
.
4.
Steinman
,
D.
,
Vinh
,
B.
,
Ethier
,
C.
,
Ojha
,
M.
,
Cobbold
,
R.
, and
Johnston
,
K.
,
1993
, “
A Numerical Simulation of Flow in a Two-Dimensional End-to-Side Anastomosis Model
,”
ASME J. Biomech. Eng.
,
115
, pp.
112
118
.
5.
Sottiurai
,
V. S.
,
Yao
,
J. S.
,
Batson
,
R. C.
,
Sue
,
S. L.
,
Jones
,
R.
, and
Nakamura
,
Y. A.
,
1989
, “
Distal Anastomotic Intimal Hyperplasia: Histopathologic Character and Biogenesis
,”
Ann. Vasc. Surg.
,
3
, pp.
26
33
.
6.
Davies
,
P. F.
, and
Tripathi
,
S. C.
,
1993
, “
Mechanical Stress Mechanisms and the Cell. an Endothelial Paradigm
,”
Circ. Res.
,
72
, pp.
239
245
.
7.
Fry
,
D. L.
,
1968
, “
Acute Vascular Endothelial Changes Associated With Increased Blood Velocity Gradients
,”
Circ. Res.
,
22
, pp.
165
197
.
8.
Malek
,
A. M.
, and
Izumo
,
S.
,
1995
, “
Control of Endothelial Cell Gene Expression by Flow
,”
J. Biomech.
,
28
, pp.
1515
1528
.
9.
Resnick
,
N.
, and
Gimbrone
,
M. A.
, Jr.,
,
1995
, “
Hemodynamic Forces Are Complex Regulators of Endothelial Gene Expression
,”
FASEB J.
,
9
, pp.
874
882
.
10.
Kleinstreuer
,
C.
,
Lei
,
M.
, and
Archie
,
J. P.
,
1996
, “
Flow Input Waveform Effects on the Temporal and Spatial Wall Shear Stress Gradients in a Femoral Graft–Artery Connector
,”
ASME J. Biomech. Eng.
,
118
, pp.
506
510
.
11.
Lei
,
M.
,
Kleinstreuer
,
C.
, and
Archie
,
J. P.
,
1997
, “
Hemodynamic Simulations and Computer-Aided Designs of Graft–Artery Junctions
,”
ASME J. Biomech. Eng.
,
119
, pp.
343
348
.
12.
Henry
,
F.
,
Collins
,
M.
,
Hughes
,
P.
, and
How
,
T.
,
1996
, “
Numerical Investigation of Steady Flow in Proximal and Distal End-to-Side Anastomoses
,”
ASME J. Biomech. Eng.
,
118
, pp.
302
310
.
13.
Inzoli
,
F.
,
Migliavacca
,
F.
, and
Pennati
,
G.
,
1996
, “
Numerical Analysis of Steady Flow in Aorto-Coronary Bypass 3-D Model
,”
ASME J. Biomech. Eng.
,
118
, pp.
172
179
.
14.
Crawshaw
,
H. M.
,
Quist
,
W. C.
,
Serallach
,
E.
,
Valeri
,
C. R.
, and
Logerfo
,
F. W.
,
1980
, “
Flow Disturbance at the Distal End-to-Side Anastomosis. Effect of Patency of the Proximal Outflow Segment and Angle of Anastomosis
,”
Arch. Surg.
,
115
, pp.
1280
1284
.
15.
Hofer
,
M.
,
Rappitsch
,
G.
,
Perktold
,
K.
,
Trubel
,
W.
, and
Schima
,
H.
,
1996
, “
Numerical Study of Wall Mechanics and Fluid Dynamics in End-to-Side Anastomoses and Correlation to Intimal Hyperplasia
,”
J. Biomech.
,
29
, pp.
1297
12308
.
16.
Loth
,
F.
,
Jones
,
S.
,
Giddens
,
D.
,
Bassiouny
,
H.
,
Glagov
,
S.
, and
Zarins
,
C.
,
1997
, “
Measurements of Velocity and Wall Shear Stress Inside a PTFE Vascular Graft Model Under Steady Flow Conditions
,”
ASME J. Biomech. Eng.
,
119
, pp.
187
194
.
17.
White
,
S.
,
Zarins
,
C.
,
Giddens
,
D.
,
Bassiouny
,
H.
,
Loth
,
F.
,
Jones
,
S.
, and
Glagov
,
S.
,
1993
, “
Hemodynamic Patterns in Two Models of End-to-Side Vascular Graft Anastomoses: Effects of Pulsatility, Flow Division, Reynolds Number, and Hood Length
,”
ASME J. Biomech. Eng.
,
115
, pp.
104
111
.
18.
Lei
,
M.
,
Archie
,
J. P.
, and
Kleinstreuer
,
C.
,
1997
, “
Computational Design of a Bypass Graft That Minimizes Wall Shear Stress Gradients in the Region of the Distal Anastomosis
,”
J. Vasc. Surg.
,
25, pp
637
646
.
19.
Hsieh
,
H. J.
,
Li
,
N. Q.
, and
Frangos
,
J. A.
,
1993
, “
Pulsatile and Steady Flow Induces C-Fos Expression in Human Endothelial Cells
,”
J. Cell Physiol.
,
154
, pp.
143
151
.
20.
Ranjan
,
V.
, and
Diamond
,
S. L.
,
1993
, “
Fluid Shear Stress Induces Synthesis and Nuclear Localization of C-Fos in Cultured Human Endothelial Cells
,”
Biochem. Biophys. Res. Commun.
,
196
, pp.
79
84
.
21.
Hsieh
,
H. J.
,
Cheng
,
C. C.
,
Wu
,
S. T.
,
Chiu
,
J. J.
,
Wung
,
B. S.
, and
Wang
,
D. L.
,
1998
, “
Increase of Reactive Oxygen Species (ROS) in Endothelial Cells by Shear Flow and Involvement of ROS in Shear-Induced C-Fos Expression
,”
J. Cell Physiol.
,
175
, pp.
156
162
.
22.
Nagel
,
T.
,
Resnick
,
N.
,
Dewey
,
C. F.
, Jr.
, and
Gimbrone
,
M. A.
, Jr.
,
1999
, “
Vascular Endothelial Cells Respond to Spatial Gradients in Fluid Shear Stress by Enhanced Activation of Transcription Factors
,”
Arterioscler., Thromb., Vasc. Biol.
,
19
, pp.
1825
1834
.
23.
DePaola
,
N.
,
Gimbrone
, Jr.,
M. A.
,
Davies
,
P. F.
, and
Dewey
, Jr.,
C. F.
,
1992
, “
Vascular Endothelium Responds to Fluid Shear Stress Gradients [Published Erratum Appears in Arterioscler. Thromb., 1993 Mar;13(3):465]
,”
Arterioscler. Thromb.
,
12
, pp.
1254
1257
.
24.
Liu
,
S. Q.
,
1999
, “
Focal Expression of Angiotensin II Type 1 Receptor and Smooth Muscle Cell Proliferation in the Neointima of Experimental Vein Grafts: Relation to Eddy Blood Flow
,”
Arterioscler., Thromb., Vasc. Biol.
,
19
, pp.
2630
2639
.
25.
Bertolotti
,
C.
, and
Deplano
,
V.
,
2000
, “
Three-Dimensional Numerical Simulations of Flow Through a Stenosed Coronary Bypass [in Process Citation
],”
J. Biomech.
,
33
, pp.
1011
1022
.
26.
Hughes
,
P.
, and
How
,
T.
,
1996
, “
Effects of Geometry and Flow Division on Flow Structures in Models of the Distal End-to-Side Anastomosis
,”
J. Biomech.
,
29
, pp.
855
872
.
27.
Li
,
X.-M.
and
Rittgers
,
S. E.
,
1999
, “
Hemodynamic Factors at the Distal End-to-Side Anastomosis of a Bypass Graft With Different POS:DOS Ratios
,” Proc. ASME Bioengineering Conference,
ASME BED
-Vol.
42
, pp.
225
226
.
28.
Perktold
,
K.
,
Resch
,
M.
, and
Peter
,
R.
,
1991
, “
Three- Dimensional Numerical Analysis of Pulsatile Flow and Wall Shear Stress in the Carotid Artery Bifurcation
,”
J. Biomech.
,
24
, pp.
409
420
.
29.
Fei
,
D. Y.
,
Thomas
,
J. D.
, and
Rittgers
,
S. E.
,
1994
, “
The Effect of Angle and Flow Rate Upon Hemodynamics in Distal Vascular Graft Anastomoses: a Numerical Model Study
,”
ASME J. Biomech. Eng.
,
116
, pp.
331
336
.
30.
Moore
,
J. A.
,
Steinman
,
D. A.
,
Prakash
,
S.
,
Johnston
,
K. W.
, and
Ethier
,
C. R.
,
1999
, “
A Numerical Study of Blood Flow Patterns in Anatomically Realistic and Simplified End-to-Side Anastomoses
,”
ASME J. Biomech. Eng.
,
121
, pp.
265
272
.
31.
Okadome
,
K.
,
Yukizane
,
T.
,
Mii
,
S.
, and
Sugimachi
,
K.
,
1990
, “
Ultrastructural Evidence of the Effects of Shear Stress Variation on Intimal Thickening in Dogs With Arterially Transplanted Autologous Vein Grafts
,”
J. Cardiovasc. Surg. (Torino)
,
31
, pp.
719
726
.
32.
Painter
,
T. A.
,
1991
, “
Myointimal Hyperplasia: Pathogenesis and Implications. 2. Animal Injury Models and Mechanical Factors
,”
Artif. Organs
,
15
, pp.
103
118
.
33.
Ishibashi
,
H.
,
Sunamura
,
M.
, and
Karino
,
T.
,
1995
, “
Flow Patterns and Preferred Sites of Intimal Thickening in End-to-End Anastomosed Vessels
,”
Surgery
,
117
, pp.
409
420
.
34.
Cucina
,
A.
,
Sterpetti
,
A. V.
,
Borrelli
,
V.
,
Pagliei
,
S.
,
Cavallaro
,
A.
, and
D’Angelo
,
L. S.
,
1998
, “
Shear Stress Induces Transforming Growth Factor-Beta 1 Release by Arterial Endothelial Cells
,”
Surgery
,
123
, pp.
212
217
.
35.
Huynh
,
T. T.
,
Davies
,
M. G.
,
Trovato
,
M. J.
,
Svendsen
,
E.
, and
Hagen
,
P. O.
,
1999
, “
Alterations in Wall Tension and Shear Stress Modulate Tyrosine Kinase Signaling and Wall Remodeling in Experimental Vein Grafts
,”
J. Vasc. Surg.
,
29
, pp.
334
344
.
36.
Keynton
,
R.S.
,
Evancho
,
M. M.
,
Sims
,
R. L.
, and
Rittgers
,
S. E.
,
1999
, “
The Effect of Graft Caliber Upon Wall Shear Within in Vivo Distal Vascular Anastomoses
,”
ASME J. Biomech. Eng.
,
121
, pp.
79
88
.
37.
Ray
,
L
,
O’Connor
,
J.
,
Davis
,
C.
,
Hall
,
D.
,
Mansfield
,
P.
,
Rittenhouse
,
E.
,
Smith
,
J.
,
Wood
,
S.
, and
Sauvage
,
L.
,
1979
, “
Axillofemoral Bypass: a Critical Reappraisal of Its Role in the Management of Aortoiliac Occlusive Disease
,”
Am. J. Surg.
,
138
, pp.
117
128
.
You do not currently have access to this content.