Although deployed in the vasculature to expand vessel diameter and improve blood flow, protruding stent struts can create complex flow environments associated with flow separation and oscillating shear gradients. Given the association between magnitude and direction of wall shear stress (WSS) and endothelial phenotype expression, accurate representation of stent-induced flow patterns is critical if we are to predict sites susceptible to intimal hyperplasia. Despite the number of stents approved for clinical use, quantification on the alteration of hemodynamic flow parameters associated with the Gianturco Z-stent is limited in the literature. In using experimental and computational models to quantify strut-induced flow, the majority of past work has assumed blood or representative analogs to behave as Newtonian fluids. However, recent studies have challenged the validity of this assumption. We present here the experimental quantification of flow through a Gianturco Z-stent wire in representative Newtonian and non-Newtonian blood analog environments using particle image velocimetry (PIV). Fluid analogs were circulated through a closed flow loop at physiologically appropriate flow rates whereupon PIV snapshots were acquired downstream of the wire housed in an acrylic tube with a diameter characteristic of the carotid artery. Hemodynamic parameters including WSS, oscillatory shear index (OSI), and Reynolds shear stresses (RSS) were measured. Our findings show that the introduction of the stent wire altered downstream hemodynamic parameters through a reduction in WSS and increases in OSI and RSS from nonstented flow. The Newtonian analog solution of glycerol and water underestimated WSS while increasing the spatial coverage of flow reversal and oscillatory shear compared to a non-Newtonian fluid of glycerol, water, and xanthan gum. Peak RSS were increased with the Newtonian fluid, although peak values were similar upon a doubling of flow rate. The introduction of the stent wire promoted the development of flow patterns that are susceptible to intimal hyperplasia using both Newtonian and non-Newtonian analogs, although the magnitude of sites affected downstream was appreciably related to the rheological behavior of the analog. While the assumption of linear viscous behavior is often appropriate in quantifying flow in the largest arteries of the vasculature, the results presented here suggest this assumption overestimates sites susceptible to hyperplasia and restenosis in flow characterized by low and oscillatory shear.

References

References
1.
Moore
,
J. E.
, Jr.
, and
Berry
,
J. L.
, 2002, “
Fluid and Solid Mechanical Implications of Vascular Stenting
,”
Ann. Biomed. Eng.
,
30
, pp.
498
508
.
2.
Benard
,
N.
,
Coisne
,
D.
,
Donal
,
E.
, and
Perrault
,
R.
, 2003, “
Experimental Study of Laminar Blood Flow Through an Artery Treated by a Stent Implantation: Characterisation of Intra-Stent Wall Shear Stress
,”
J. Biomech.
,
36
, pp.
991
998
.
3.
Balakrishnan
,
B.
,
Tzafriri
,
A. R.
,
Seifert
,
P.
,
Groothuis
,
A.
,
Rogers
,
C.
, and
Edelman
,
E. R.
, 2005, “
Strut Position, Blood Flow, and Drug Deposition: Implications for Single and Overlapping Drug-Eluting Stents
,”
Circulation
,
111
, pp.
2958
2965
.
4.
Yazdani
,
S. K.
,
Moore
,
J. E.
, Jr.
,
Berry
,
J. L.
, and
Vlachos
,
P. P.
, 2004, “
DPIV Measurements in Stented Artery Models: Adverse Affects of Compliance Mismatch
,”
J. Biomech. Eng.
,
126
, pp.
559
566
.
5.
Berry
,
J. L.
,
Santamarina
,
A.
,
Moore
,
J. E.
, Jr.
,
Roychowdhury
,
S.
, and
Routh
,
W. D.
, 2000, “
Experimental and Computational Flow Evaluation of Coronary Stents
,”
Ann. Biomed. Eng.
,
28
, pp.
386
398
.
6.
Duraiswamy
,
N.
,
Schoephoerster
,
R. T.
,
Moreno
,
M. R.
, and
Moore
,
J. E.
, Jr
., 2007, “
Stented Artery Flow Patterns and Their Effects on the Artery Wall
,”
Annu. Rev. Fluid Mech.
,
39
, pp.
357
382
.
7.
LaDisa
,
J. F.
, Jr.
,
Guler
,
I.
,
Olson
,
L. E.
,
Hettrick
,
D. A.
,
Kersten
,
J. R.
,
Warltier
,
D. C.
, and
Pagel
,
P. S.
, 2003, “
Three-Dimensional Computational Fluid Dynamics Modeling of Alternations in Coronary Wall Shear Stress Produced by Stent Implantation
,”
Ann. Biomed. Eng.
,
31
, pp.
972
980
.
8.
LaDisa
,
J. F.
, Jr.
,
Olson
,
L. E.
,
Guler
,
I.
,
Hettrick
,
D. A.
,
Kersten
,
J.R.
,
Warltier
,
D. C.
, and
Pagel
,
P. S.
, 2005, “
Circumferential Vascular Deformation After Stent Implantation Alters Wall Shear Stress Evaluated With Time-Dependent 3D Computational Fluid Dynamics Models
,”
J. Appl. Physiol.
,
98
, pp.
947
957
.
9.
Charonko
,
J.
,
Karri
,
S.
,
Schmieg
,
J.
,
Prabhu
,
S.
, and
Vlachos
,
P.
, 2009, “
In Vitro, Time-Resolved PIV Comparison of the Effect of Stent Design on Wall Shear Stress
,”
Ann. Biomed. Eng.
,
37
, pp.
1310
1321
.
10.
Johnston
,
B. M.
,
Johnston
,
P. R.
,
Corney
,
S.
, and
Kilpatrick
,
D.
, 2006, “
Non-Newtonian Blood Flow in Human Right Coronary Arteries: Transient Simulations
,”
J. Biomech.
,
39
, pp.
1116
1128
.
11.
Mejia
,
J.
,
Mongrain
,
R.
, and
Bertrand
,
O. F.
, 2011, “
Accurate Prediction of Wall Shear Stress in a Stented Artery: Newtonian Versus Non-Newtonian Models
,”
J. Biomech. Eng.
,
133
, p.
074501
.
12.
Cavazzuti
,
M.
,
Atherton
,
M. A.
,
Collins
,
M. W.
, and
Barozzi
,
G. S.
, 2011, “
Non-Newtonian and Flow Pulsatility Effects in Simulation Models of a Stented Intracranial Aneurysm
,”
Proc. Inst. Mech. Eng., Part H: J. Eng. Med.
,
225
, pp.
597
609
.
13.
Benard
,
N.
,
Perrault
,
R.
, and
Coisne
,
D.
, 2006, “
Computational Approach to Estimating the Effects of Blood Properties on Changes in Intra-Stent Flow
,”
Ann. Biomed. Eng.
,
34
, pp.
1259
1271
.
14.
Berry
,
J. L.
,
Newman
,
V. S.
,
Ferrario
,
C. M.
,
Routh
,
W. D.
, and
Dean
,
R. H.
, 1996, “
A Method to Evaluate the Elastic Behavior of Vascular Stents
,”
J. Vasc. Interv. Radiol.
,
7
, pp.
381
385
.
15.
Johnston
,
C. R.
,
Lee
,
K.
,
Flewitt
,
J.
,
Moore
,
R.
,
Dobson
,
G. M.
, and
Thornton
,
G. M.
, 2010, “
The Mechanical Properties of Endovascular Stents: An In Vitro Assessment
,”
Cardiovasc. Eng.
,
10
, pp.
128
135
.
16.
Malina
,
M.
,
Brunkwall
,
J.
,
Ivancev
,
K.
,
Lindh
,
M.
,
Lindblad
,
B.
, and
Risberg
,
B.
, 1997, “
Renal Arteries Covered by Aortic Stents: Clinical Experience From Endovascular Grafting of Aortic Aneurysms
,”
Eur. J. Vasc. Endovasc. Surg.
,
14
, pp.
109
113
.
17.
May
,
A.
, and
Ell
,
C.
, 1998, “
Palliative Treatment of Malignant Esophagorespiratory Fistulas With Gianturco-Z Stents. A Prospective Clinical Trial and Review of the Literature on Covered Metal Stents
,”
Am. J. Gastroenterol.
,
93
, pp.
532
535
.
18.
Gaines
,
P. A.
,
Belli
,
A.-M.
,
Anderson
,
P. B.
,
McBride
,
K.
, and
Hemingway
,
A. P.
, 1994, “
Superior Vena Caval Obstruction Managed by the Gianturco Z Stent
,”
Clin. Radiol.
,
49
, pp.
202
208
.
19.
Davidian
,
M.
,
Kee
,
S. T.
,
Kato
,
N.
,
Semba
,
C. P.
,
Razavi
,
M. K.
,
Mitchell
,
R. S.
, and
Dake
,
M. D.
, 1998, “
Aneurysm of an Aberrant Right Subclavian Artery: Treatment With PTFE Covered Stentgraft
,”
J. Vasc. Surg.
,
28
, pp.
335
339
.
20.
Guivier-Curien
,
C.
,
Deplano
,
V.
,
Betrand
,
E.
,
Singland
,
J. D.
, and
Koskas
,
F.
, 2009, “
Analysis of Blood Flow Behavior in Custom Stent Grafts
,”
J. Biomech.
,
42
, pp.
1754
1761
.
21.
Cheng
,
S. W. K.
,
Lam
,
E. S. K.
,
Fung
,
G. S. K.
,
Ho
,
P.
,
Ting
,
A. C. W.
, and
Chow
,
K. W.
, 2008, “
A Computational Fluid Dynamic Study of Stent Graft Remodeling After Endovascular Repair of Thoracic Aortic Dissections
,”
J. Vasc. Surg.
,
48
, pp.
303
310
.
22.
Brookshier
,
K. A.
, and
Tarbell
,
J. M.
, 1994, “
Evaluation of a Transparent Blood Analog Fluid: Aqueous Xanthan Gum/Glycerin
,”
Biorheology
,
30
, pp.
107
116
.
23.
Liepsch
,
D. W.
, 1986, “
Flow in Tubes and Arteries—A Comparison
,”
Biorheology
,
23
, pp.
395
433
.
24.
Hochareon
,
P.
,
Manning
,
K. B.
,
Fontaine
,
A. A.
,
Tarbell
,
J. M.
, and
Deutsch
,
S.
, 2004, “
Wall Shear-Rate Estimation Within the 50cc Penn State Artificial Heart Using Particle Image Velocimetry
,”
J. Biomech Eng.
,
126
, pp.
431
437
.
25.
Kähler
,
C. J.
,
Scholz
,
U.
, and
Ortmanns
,
J.
, 2006, “
Wall-Shear-Stress and Near-Wall Turbulence Measurements Up to Single Pixel Resolution by Means of Long-Distance Micro-PIV
,”
Exp. Fluids
,
41
, pp.
327
341
.
26.
Peterson
,
S. D.
, and
Plesniak
,
M. W.
, 2008, “
The Influence of Inlet Velocity Profile and Secondary Flow on Pulsatile Flow in a Model Artery With Stenosis
,”
J. Fluid. Mech.
,
616
, pp.
263
301
.
27.
Schlichting
,
H.
, and
Gersten
,
K.
, 2000,
Boundary-Layer Theory
,
Springer-Verlag
,
Berlin, Germany
.
28.
Buchmann
,
N. A.
, and
Jermy
,
M. C.
, 2008, “
Blood Flow Measurements in Idealised and Patient Specific Models of the Human Carotid Artery
,” Proceedings of the 14th International Symposium on Applications of Laser Techniques to Fluid Mechanics, Lisbon, Portugal.
29.
Geoghegan
,
P. H.
,
Buchmann
,
N. A.
,
Spence
,
C. J. T.
,
Moore
,
S.
, and
Jermy
,
M.
, 2011, “
Fabrication of Rigid and Flexible Refractive Index Matched Flow Phantoms for Flow Visualisation and Optical Flow Measurements
,”
Exp. Fluids
,
52
, pp.
1331
1347
.
30.
Theunissen
,
R.
,
Scarano
,
F.
, and
Riethmuller
,
M. L.
, 2008, “
On Improvement of PIV Image Interrogation Near Stationary Interfaces
,”
Exp. Fluids
,
45
, pp.
557
572
.
31.
Masaryk
,
A. M.
,
Frayne
,
R.
,
Unal
,
O.
,
Krupinski
,
E.
, and
Strother
,
C. M.
, 1999, “
In Vitro and In Vivo Comparison of Three MR Measurement Methods for Calculating Vascular Shear Stress in the Internal Carotid Artery
,”
AJNR Am. J. Neuroradiol.
,
20
, pp.
237
245
.
32.
Lou
,
Z.
,
Yang
,
W.-J.
, and
Stein
,
P. D.
, 1993, “
Errors in the Estimation of Arterial Wall Shear Rates That Result From Curve Fitting of Velocity Profiles
,”
J. Biomech.
,
26
, pp.
383
390
.
33.
Ku
,
D. N.
,
Giddens
,
D. P.
,
Zarins
,
C. K.
, and
Glagov
,
S.
, 1985, “
Pulsatile Flow and Atherosclerosis in the Human Carotid Bifurcation. Positive Correlation Between Plaque Location and Low Oscillating Shear Stress
,”
Arterioscler., Thromb., Vasc. Biol.
,
5
, pp.
293
302
.
34.
Yoganathan
,
A. P.
,
Woo
,
Y.-R.
, and
Sung
,
H.-W.
, 1986, “
Turbulent Shear Stress Measurements in the Vicinity of Aortic Heart Valve Prostheses
,”
J. Biomech.
,
19
, pp.
433
442
.
35.
Nygaard
,
H.
,
Paulsen
,
P. K.
,
Hasenkam
,
J. M.
,
Pedersen
,
E. M.
, and
Rovsing
,
P. E.
, 1994, “
Turbulent Stresses Downstream of Three Mechanical Aortic Valve Prostheses in Human Beings
,”
J. Thorac. Cardiovasc. Surg.
,
107
, pp.
438
446
.
36.
Reneman
,
R. S.
,
Arts
,
T.
, and
Hoeks
,
A. P.
, 2006, “
Wall Shear Stress—An Important Determinant of Endothelial Cell Function and Structure—In the Arterial System In Vivo
,”
J. Vasc. Res.
,
43
, pp.
251
269
.
37.
Nordgaard
,
H.
,
Swillens
,
A.
,
Nordhaug
,
D.
,
Kirkeby-Garstad
,
I.
,
Van Loo
,
D.
,
Vitale
,
N.
,
Segers
,
P.
,
Haaverstad
,
R.
, and
Lovstakken
,
L.
, 2010, “
Impact of Competitive Flow on Wall Shear Stress in Coronary Surgery: Computational Fluid Dynamics of a LIMA-LAD Model
,”
Cardiovasc. Res.
,
88
, pp.
512
519
.
38.
Malek
,
A. M.
,
Alper
,
S. L.
, and
Izumo
,
S.
, 1999, “
Hemodynamic Shear Stress and Its Role in Atherosclerosis
,”
JAMA, J. Am. Med. Assoc.
,
282
, pp.
2035
2042
.
39.
Schirmer
,
C. M.
, and
Malek
,
A. M.
, 2007, “
Wall Shear Stress Gradient Analysis Within an Idealized Stenosis Using Non-Newtonian Flow
,”
Neurosurgery
,
61
, pp.
855
864
.
40.
Hemlinger
,
G.
,
Geiger
,
R. V.
,
Schreck
,
S.
, and
Nerem
,
R. M.
, 1991, “
Effects of Pulsatile Flow on Cultured Vascular Endothelial Cell Morphology
,”
J. Biomech. Eng.
,
113
, pp.
123
131
.
41.
Ku
,
D. N.
, and
Giddens
,
D. P.
, 1983, “
Pulsatile Flow in a Model Carotid Bifurcation
,”
Arterioscler., Thromb., Vasc. Biol.
,
3
, pp.
31
39
.
42.
Chong
,
C. K.
,
How
,
T. V.
, and
Harris
,
P. L.
, 2005, “
Flow Visualization in a Model of a Bifurcated Stent-Graft
,”
J. Endovasc. Ther.
,
12
, pp.
435
445
.
43.
Razavi
,
A.
,
Shirani
,
E.
, and
Sadeghi
,
M. R.
, 2011, “
Numerical Simulation of Blood Pulsatile Flow in a Stenoses Carotid Artery Using Different Rheological Models
,”
J. Biomech.
,
44
, pp.
2021
2030
.
44.
Gijsen
,
F. J. H.
,
van de Vosse
,
F. N.
, and
Janssen
,
J. D.
, 1999, “
The Influence of the Non-Newtonian Properties of Blood on the Flow in the Large Arteries: Steady Flow in a Carotid Bifurcation Model
,”
J. Biomech.
,
32
, pp.
601
608
.
45.
Chien
,
S
., 2008, “
Effects of Disturbed Flow on Endothelial Cells
,”
Ann. Biomed. Eng.
,
36
, pp.
554
562
.
46.
Lu
,
P. C.
,
Lai
,
H. C.
, and
Liu
,
J. S.
, 2001, “
A Reevaluation and Discussion on the Threshold Limit for Hemolysis in a Turbulent Shear Flow
,”
J. Biomech.
,
34
, pp.
1361
1364
.
47.
Slack
,
S. M.
, and
Turitto
,
V. T.
, 1993, “
Chapter 2: Fluid Dynamic and Hemorheologic Considerations
,”
Cardiovasc. Pathol.
,
2
, pp.
11S
21S
.
48.
Jiang
,
Z. L.
,
Yamaguchi
,
H.
,
Tanaka
,
H.
,
Takahashi
,
A.
,
Tanabe
,
S.
,
Utsuyama
,
N.
,
Ikehara
,
T.
,
Hosokawa
,
K.
,
Kinouchi
,
Y.
, and
Miyamoto
,
H.
, 1995, “
Blood Flow Velocity in the Common Carotid Artery in Humans During Graded Exercise on a Treadmill
,”
Eur. J. Appl. Physiol.
,
70
, pp.
234
239
.
49.
Robaina
,
S.
,
Jayachandran
,
B.
,
He
,
Y.
,
Frank
,
A.
,
Moreno
,
M. R.
,
Schoephoerster
,
R. T.
, and
Moore
,
J. E.
, Jr.
, 2003, “
Platelet Adhesion to Simulated Stented Surfaces
,”
J. Endovasc. Ther.
,
10
, pp.
978
986
.
50.
Sukavaeshvar
,
S.
,
Rosa
,
G. M.
, and
Solen
,
K. A.
, 2000, “
Enhancement of Stent-Induced Thromboembolism by Residual Stenoses: Contribution of Hemodynamics
,”
Ann. Biomed. Eng.
,
28
, pp.
182
193
.
51.
Peacock
,
J.
,
Hankins
,
S.
,
Jones
,
T.
, and
Lutz
,
R.
, 1995, “
Flow Instabilities Induced by Coronary Artery Stents: Assessment With an In Vitro Pulse Duplicator
,”
J. Biomech.
,
28
, pp.
17
26
.
52.
Lim
,
W. L.
,
Chew
,
Y. T.
,
Chew
,
T. C.
, and
Low
,
H. T.
, 2001, “
Pulsatile Flow Studies of a Porcine Bioprosthetic Aortic Valve In Vitro: PIV Measurements and Shear-Induced Blood Damage
,”
J. Biomech.
,
34
, pp.
1417
1427
.
53.
Bortolotto
,
L. A.
,
Hanon
,
O.
,
Franconi
,
G.
,
Boutouyrie
,
P.
,
Legrain
,
S.
, and
Girerd
,
X.
, 1999, “
The Aging Process Modifies the Distensibility of Elastic but not Muscular Arteries
,”
Hypertension
,
34
, pp.
889
892
.
54.
Ku
,
D. N.
, and
Liepsch
,
D.
, 1986, “
The Effects of Non-Newtonian Viscoelasticity and Wall Elasticity on Flow at a 90 Degrees Bifurcation
,”
Biorheology
,
23
, pp.
359
370
.
55.
Rhee
,
K.
, and
Tarbell
,
J. M.
, 1994, “
A Study of the Wall Shear Rate Distribution Near the End-To-End Anastomosis of a Rigid Graft and a Compliant Artery
,”
J. Biomech.
,
27
, pp.
329
338
.
56.
Dammers
,
R.
,
Tordoir
,
J. H. M.
,
Hameleers
,
J. M. M.
,
Kitslaar
,
P. J. E. H. M.
, and
Hoeks
,
A. P. G.
, 2002, “
Brachial Artery Shear Stress is Independent of Gender or Age and does not Modify Vessel Wall Mechanical Properties
,”
Ultrasound Med. Biol.
,
28
, pp.
1015
1022
.
57.
Cinar
,
Y.
,
Senyol
,
A. M.
, and
Duman
,
K.
, 2001, “
Blood Viscosity and Blood Pressure: Role of Temperature and Hyperglycemia
,”
Am. J. Hypertens.
,
14
, pp.
433
438
.
58.
Kähler
,
C. J.
,
Scharnowski
,
S.
, and
Cierpka
,
C.
, 2012, “
On the Resolution Limit of Digital Particle Image Velocimetry
,”
Exp. Fluids
,
52
, pp.
1629
1639
.
59.
Kähler
,
C. J.
,
Scharnowski
,
S.
, and
Cierpka
,
C.
, 2012, “
On the Uncertainty of Digital PIV and PTV Near Walls
,”
Exp. Fluids
,
52
, pp.
1641
1656
.
60.
Schlüter
,
T.
, and
Merzkirch
,
W.
, 1996, “
PIV Measurements of the Time-Averaged Flow Velocity Downstream of Flow Conditioners in a Pipeline
,”
Flow Meas. Instrum.
,
7
, pp.
173
179
.
You do not currently have access to this content.