Laminar and turbulent numerical simulations of steady flow in an aneurysm model were carried out over Reynolds numbers ranging from 300 to 3600. The numerical simulations are validated with Digital Particle Image Velocimetry (DPIV) measurements, and used to study the fluid dynamic mechanisms that characterize aneurysm deterioration, by correlating them to in vitro blood platelet deposition results. It is shown that the recirculation zone formed inside the aneurysm cavity creates conditions that promote thrombus formation and the viability of rupture. Wall shear stress values in the recirculation zone are around one order of magnitude less than in the entrance zone. The point of reattachment at the distal end of the aneurysm is characterized by a pronounced wall shear stress peak. As the Reynolds number increases in laminar flow, the center of the recirculation region migrates toward the distal end of the aneurysm, increasing the pressure at the reattachment point. Under fully turbulent flow conditions (Re = 3600) the recirculation zone inside the aneurysm shrinks considerably. The wall shear stress values are almost one order of magnitude larger than those for the laminar cases. The fluid dynamics mechanisms inferred from the numerical simulation were correlated with measurements of blood platelet deposition, offering useful explanations for the different morphologies of the platelet deposition curves.

1.
Aarts
P. A.
,
van Den
M. M.
,
Broek
S. A. T.
,
Prins
G. W.
,
Kuiken
D. C.
,
Sixma
J. J.
, and
Heethaar
R. M.
,
1988
, “
Blood Platelets Are Concentrated Near the Wall and Red Blood Cells, in the Center in Flowing Blood
,”
Arteriosclerosis
, Vol.
8
, pp.
819
824
.
2.
Bluth
E. I.
,
Murphey
S. M.
,
Hollier
L. H.
, and
Sullivan
M. A.
,
1990
, “
Color Flow Doppler in the Evaluation of Aortic Aneurysms
,”
Int. Angio.
, Vol.
9
, pp.
8
10
.
3.
Budwig
R.
,
Elgar
D.
,
Hooper
H.
,
Slippy
J.
,
1993
, “
Steady Flow in Abdominal Aortic Aneurysm Models
,”
J. Biomed. Engr.
, Vol.
115
, pp.
418
423
.
4.
Caro
C. G.
,
Fitzgerald
J. M.
, and
Schroter
R. C.
,
1971
, “
Atheroma and Wall Shear. Observation, Correlation and Proposal of a Shear Dependent Mass Transfer Mechanism for Atherogenesis
.”
Proc. Royal Soc. London, Series B
, Vol.
177
, pp.
109
159
.
5.
Christenson
J. T.
,
Mergerman
J.
,
Hanel
K. C.
,
L’ltalien
G. J.
,
Strauss
H. W.
, and
Abbott
W. M.
,
1981
, “
The Effect of Blood Plow Rates on Platelet Deposition in PTFE Arterial Bypass Grafts
,”
Trans. ASAIO
, Vol.
27
, pp.
188
191
.
6.
Dorbin
P. B.
,
1989
, “
Pathophysiology and Pathogenesis of Aortic Aneurysms
,”
Surg. Clin of N. Amer.
, Vol.
69
, pp.
689
703
.
7.
Drexler, D. J., and Hoffman, A. H., 1985, “Steady Flow through Several Aneurysm Models,” Proc. Eleventh Ann. NE Bioengr. Conf., W. Kuklinsky and W. Ohley, eds., pp. 147–150.
8.
Eckstein
E. C.
, and
Belgacem
F.
,
1991
, “
Model of Platelet Transport in Flowing Blood with Drift and Diffusion Terms
,”
Biophys. J.
, Vol.
60
, pp.
53
69
.
9.
Ernst
C. B.
,
1993
, “
Abdominal Aortic Aneurysm
,”
New England J. Med.
, Vol.
328
(
16
), pp.
1167
72
.
10.
Folie
B. J.
, and
Mclntire
L. V.
,
1989
, “
Mathematical Analysis of Mural Thrombogenesis: Concentration Profiles of Platelet-Activating Agents and Effects of Viscous Shear Flow
,”
Biophysical J.
, Vol.
56
(
1
), pp.
1121
1141
.
11.
Friedman
M. H.
,
Hutchins
G. M.
, and
Bargeron
C. B.
,
1981
, “
Correlation Between Intimal Thickness and Fluid Shaer in Human Arteries
,”
Atherosclerosis
, Vol.
39
, pp.
425
436
.
12.
Friedman
M. H.
,
Bargeron
C. B.
,
Duncan
D. D.
,
Hutchins
G. M.
, and
Mark
F. F.
,
1992
, “
Effects of Arterial Compliance and Non-Newtonian Rehology on Correlation Between Intimal Thickness and Wall Shear
,”
ASME JOURNAL OF BIOMECHANICAL ENGINEERING
, Vol.
109
, pp.
317
320
.
13.
Fry
D. L.
,
1968
, “
Acute Vascular Endothelial Changes Associated With Increased Blood Velocity Gradients
,”
Circulation Research
, Vol.
22
, pp.
165
197
.
14.
Fukushima
T.
,
Matszuzawa
T.
, and
Homma
T.
,
1986
, “
Visualization and Finite Element Analysis of Pulsatile Flow in Models of Abdominal Aortic Aneurysm
,”
Biorehology
, Vol.
26
, pp.
109
130
.
15.
Ingoldby
C. J. H.
,
Wujanto
R.
,
Mitchell
J. E.
,
1986
, “
Impact of Vascular Surgery on Community Mortality From Ruptured Aortic Aneurysms
,”
Br. J. Surg.
, Vol.
73
, pp.
551
3
.
16.
Johansen
K. H.
,
1982
, “
Aneurysms
,”
Scientific American
, Vol.
247
, pp.
110
125
.
17.
Karino
T.
, and
Goldsmith
H. L.
,
1979
a, “
Aggregation of Human Platelets in an Annular Vortex Distal to a Tubular Expansion
,”
Microvasc. Research
, Vol.
17
, pp.
217
237
.
18.
Karino
T.
, and
Goldsmith
H. L.
,
1979
b, “
Adhesion of Human Platelets to Collagen on the Walls Distal to a Tubular Expansion
,”
Microvasc. Research
, Vol.
17
, pp.
238
262
.
19.
Karino, T., Goldsmith, H. L., Motomiya, M., Mabuchi, S., and Sohara, Y., 1987, “Flow Patterns in Vessels of Simple and Complex Geometries,” Blood in Contact with Natural and Artificial Surfaces, Leonard, E. F., Turitto, V. T., and Vroman, L., eds., New York Academy of Sciences, New York, pp. 422–441.
20.
Ku
D. N.
,
Giddens
D. P.
,
Zarins
Z. S.
, and
Glagov
S.
,
1985
, “
Pulsatile Flow and Atherosclerosis in Human Carotid Bifurcation
,”
Atherosclerosis
, Vol.
5
, pp.
1047
60
.
21.
Lelah
M. D.
,
Lamprecht
L. K.
, and
Cooper
S. L.
,
1984
, “
A Canine Ex Vivo Series Shunt for Evaluating Thrombus Deposition on Polymer Surfaces
,”
J. Biomed. Mater. Res.
, Vol.
18
, pp.
475
496
.
22.
Muraki
N.
,
1983
, “
Ultrasonic Studies of the Abdominal Aorta with Special Reference to Hemodynamic Considerations on Thrombus Formation in the Abdominal Aortic Aneurysm
,”
J. Japanese College Angiology
, Vol.
23
, pp.
401
413
.
23.
Perktold
K.
,
1987
, “
On the Paths of Fluid Particles in an Axisymmetric Aneurysm
,”
J. Biomechanics
, Vol.
20
, pp.
311
317
.
24.
Schoephoerster
R. T.
,
Oynes
F.
,
Nunez
H.
,
Kapadvanjwala
M.
, and
Dewanjee
M. K.
,
1993
, “
Effects of Local Geometry and Fluid Dynamics on Regional Platelet Deposition on Artificial Surfaces
,”
Artherosclerosis and Thrombosis 13
, Vol.
12
, pp.
1806
1813
.
25.
Steiger
H. J.
,
1990
, “
Pathophysiology and Development of Rupture of Cerebral Aneurysms
,”
Acta Neurchir. Suppl. (Wien)
, Vol.
48
, pp.
1
57
.
26.
Stein
P. D.
, and
Sabbah
H. N.
,
1974
, “
Measured Turbulence and its Effect on Thrombus Formation
,”
Circ. Research.
, Vol.
35
, pp.
608
614
.
27.
Tangelder
G. J.
,
Slaaf
D. W.
,
Teirlink
H. C.
,
Alewijnse
R.
, and
Reneman
R. S.
,
1982
, “
Localization Within a Thin Optical Section of Fluorescent Blood Platelets Flowing in a Microvessel
,”
Microvasc. Res.
, Vol.
23
, pp.
214
230
.
28.
Taylor
T. W.
, and
Yamaguchi
T.
,
1994
, “
Three Dimensional Simulation of Blood Flow in an Abdominal Aortic Aneurysm-Steady and Unsteady Flow Cases
,”
J. Biomech. Engr.
, Vol.
116
, pp.
89
97
.
29.
Thomas
P. R. S.
, and
Stewart
R. D.
,
1988
,
Br. J. Surg.
, Vol.
73
, pp.
101
3
.
30.
Willert
C. E.
, and
Gharib
M.
,
1991
, “
Digital Particle Image Velocimetry
,”
Experiments in Fluids
, Vol.
10
, pp.
181
193
.
31.
Wille
S. O.
,
1981
, “
Pulsating Pressure and Flow in an Arterial Aneurysm Simulated in a Mathematical Model
,”
J. Biomed. Engr.
, Vol.
3
, pp.
153
158
.
32.
Young
D. F.
,
1979
, “
Fluid Mechanics of Arterial Stenosis
,”
ASME JOURNAL OF BLOMECHANICAL ENGINEERING
, Vol.
101
, pp.
101
157
.
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