A stent is a device designed to restore flow through constricted arteries. These tubular scaffold devices are delivered to the afflicted region and deployed using minimally invasive techniques. Stents must have sufficient radial strength to prop the diseased artery open. The presence of a stent can subject the artery to abnormally high stresses that can trigger adverse biologic responses culminating in restenosis. The primary aim of this investigation was to investigate the effects of varying stent “design parameters” on the stress field induced in the normal artery wall and the radial displacement achieved by the stent. The generic stent models were designed to represent a sample of the attributes incorporated in present commercially available stents. Each stent was deployed in a homogeneous, nonlinear hyperelastic artery model and evaluated using commercially available finite element analysis software. Of the designs investigated herein, those employing large axial strut spacing, blunted corners, and higher amplitudes in the ring segments induced high circumferential stresses over smaller areas of the artery’s inner surface than all other configurations. Axial strut spacing was the dominant parameter in this study, i.e., all designs employing a small stent strut spacing induced higher stresses over larger areas than designs employing the large strut spacing. Increasing either radius of curvature or strut amplitude generally resulted in smaller areas exposed to high stresses. At larger strut spacing, sensitivity to radius of curvature was increased in comparison to the small strut spacing. With the larger strut spacing designs, the effects of varying amplitude could be offset by varying the radius of curvature and vice versa. The range of minimum radial displacements from the unstented diastolic radius observed among all designs was less than 90μm. Evidence presented herein suggests that stent designs incorporating large axial strut spacing, blunted corners at bends, and higher amplitudes exposed smaller regions of the artery to high stresses, while maintaining a radial displacement that should be sufficient to restore adequate flow.

1.
American Heart Association
, 2004, “
Heart and Stroke Statistical Update: 2004 Update
.”
2.
Kastrati
,
A.
,
Mehilli
,
J.
,
Dirschinger
,
J.
,
Pache
,
J.
,
Ulm
,
K.
,
Schulen
,
H.
,
Seyfarth
,
M.
,
Schmitt
,
C.
,
Blasini
,
R.
,
Neumann
,
F. J.
, and
Schomig
,
A.
, 2001, “
Restenosis After Coronary Placement of Various Stent Types
,”
Am. J. Cardiol.
0002-9149,
87
, pp.
34
39
.
3.
Regar
,
E.
,
Sianos
,
G.
,
Serruys
,
P. W.
, 2001, “
Stent Development and Local Drug Delivery
,”
Br. Med. Bull.
0007-1420,
59
, pp.
227
248
.
4.
Rogers
,
C.
,
Tseng
,
D. Y.
,
Squire
,
J. C.
, and
Edelman
,
E. R.
, 1999, “
Balloon-Artery Interactions During Stent Placement: A Finite Element Analysis Approach to Pressure, Compliance, and Stent Design as Contributors to Vascular Injury
,”
Circ. Res.
0009-7330,
84
(
4
), pp.
378
383
.
5.
Migliavacca
,
F.
,
Petrini
,
L.
,
Colombo
,
M.
,
Auricchio
,
F.
, and
Pietrabissa
,
R.
, 2002, “
Mechanical Behavior of Coronary Stents Investigated Through the Finite Element Method
,”
J. Biomech.
0021-9290,
35
(
6
), pp.
803
811
.
6.
Migliavacca
,
F.
,
Petrini
,
L.
,
Montanari
,
V.
,
Quagliana
,
I.
,
Auricchio
,
F.
, and
Dubini
,
G.
, 2005, “
A Predictive Study of the Mechanical Behaviour of Coronary Stents by Computer Modelling
,”
Med. Eng. Phys.
1350-4533,
27
(
1
), pp.
13
18
.
7.
Lally
,
C.
,
Dolan
,
F.
, and
Prendergast
,
P. J.
, 2005, “
Cardiovascular Stent Design and Vessel Stresses: A Finite Element Analysis
,”
J. Biomech.
0021-9290,
38
(
8
), pp.
1574
1581
.
8.
Berry
,
J. L.
,
Manoach
,
E.
,
Mekkaoui
,
C.
,
Rolland
,
P. H.
,
Moore
,
J. E.
, Jr.
, and
Rachev
,
A.
, 2002, “
Hemodynamics and Wall Mechanics of a Compliance Matching Stent: In Vitro and In Vivo Analysis
,”
J. Vasc. Interv Radiol.
1051-0443,
13
, pp.
97
105
.
9.
Holzapfel
,
G. A.
,
Stadler
,
M.
, and
Schulze-Bauer
,
C. A.
, 2002, “
A Layer-Specific Three-Dimensional Model for the Simulation of Balloon Angioplasty Using Magnetic Resonance Imaging and Mechanical Testing
,”
Ann. Biomed. Eng.
0090-6964,
30
(
6
), pp.
753
767
.
10.
Holzapfel
,
G. A.
,
Sommer
,
G.
, and
Regitnig
,
P.
, 2004, “
Anisotropic Mechanical Properties of Tissue Components in Human Atherosclerotic Plaques
,”
ASME J. Biomech. Eng.
0148-0731,
126
(
5
), pp.
657
665
.
11.
Higashida
,
R. T.
,
Meyers
,
P. M.
,
Phatouros
,
C. C.
,
Connors
,
J. J.
,
Barr
,
J. D.
, and
Sacks
,
D.
, 2004, “
Reporting Standards for Carotid Artery Angioplasty and Stent Placement
,”
Stroke
0039-2499,
35
(
5
), pp.
112
134
.
12.
Serruys
,
P. W.
, and
Kutryk
,
M. J. B.
, 2000,
Handbook of Coronary Stents
,
3rd
Edition,
Martin Dunitz Ltd.
,
London
.
13.
Humphrey
,
J. D.
,
Kang
,
T.
,
Sakarda
,
T.
, and
Anjanappa
,
M.
, 1993, “
Computer-Aided Vascular Experimentation: A New Electromechanical Test System
,”
Ann. Biomed. Eng.
0090-6964,
21
(
1
), pp.
33
43
.
14.
Holzapfel
,
G. A.
, 2000, “
A New Constitutive Framework for Arterial Wall Mechanics and a Comparative Study of Material Models
,”
J. Elast.
0374-3535,
61
, pp.
1
48
.
15.
Farb
,
A.
,
Weber
,
D. K.
,
Kolodgie
,
F. D.
,
Burke
,
A. P.
, and
Virmani
,
R.
, 2002, “
Morphological Predictors of Restenosis After Coronary Stenting in Humans
,”
Circulation
0009-7322,
105
(
25
), pp.
2974
2980
.
16.
Kollros
,
P. R.
,
Bates
,
S. R.
,
Mathews
,
M. B.
,
Horwitz
,
A. L.
, and
Glagov
,
S.
, 1987, “
Cyclic AMP Inhibits Increased Collagen Production by Cyclically Stretched Smooth Muscle Cells
,”
Lab. Invest.
0023-6837,
56
(
4
), pp.
410
417
.
17.
Sumpio
,
B. E.
,
Banes
,
A. J.
,
Levin
,
L. G.
, and
Johnson
,
G.
, Jr.
, 1987, “
Mechanical Stress Stimulates Aortic Endothelial Cells to Proliferate
,”
J. Vasc. Surg.
0741-5214,
6
(
3
), pp.
252
256
.
18.
Sumpio
,
B. E.
,
Banes
,
A. J.
,
Buckley
,
M.
, and
Johnson
,
G.
, Jr.
, 1988, “
Alterations in Aorticl Endothelial Cell Morphology and Cytoskeletal Protein synthesis During Cyclic Tensional Deformation
,”
J. Vasc. Surg.
0741-5214,
7
(
1
), pp.
130
138
.
19.
Frank
,
A. O.
,
Walsh
,
P. W.
, and
Moore
,
J. E.
, Jr.
, 2002, “
Computational Fluid Dynamics and Stent Design
,”
Artif. Organs
0160-564X,
26
(
7
), pp.
614
624
.
20.
Williamson
,
S. D.
, and
Lam
,
Y.
, 2003, “
On the Sensitivity of Wall Stresses in Diseased Arteries to Variable Material Properties
,”
ASME J. Biomech. Eng.
0148-0731,
125
, pp.
147
155
.
You do not currently have access to this content.