Abdominal aortic aneurysms (AAAs) represent permanent, localized dilations of the abdominal aorta that can be life-threatening if progressing to rupture. Evaluation of risk of rupture depends on understanding the mechanical behavior of patient AAA walls. In this project, a series of patient AAA wall tissue samples have been evaluated through a combined anamnestic, mechanical, and histopathologic approach. Mechanical properties of the samples have been characterized using a novel, strain-controlled, planar biaxial testing protocol emulating the in vivo deformation of the aorta. Histologically, the tissue ultrastructure was highly disrupted. All samples showed pronounced mechanical stiffening with stretch and were notably anisotropic, with greater stiffness in the circumferential than the axial direction. However, there were significant intrapatient variations in wall stiffness and stress. In biaxial tests in which the longitudinal stretch was held constant at 1.1 as the circumferential stretch was extended to 1.1, the maximum average circumferential stress was 330 ± 70 kPa, while the maximum average axial stress was 190 ± 30 kPa. A constitutive model considering the wall as anisotropic with two preferred directions fit the measured data well. No statistically significant differences in tissue mechanical properties were found based on patient gender, age, maximum bulge diameter, height, weight, body mass index, or smoking history. Although a larger patient cohort is merited to confirm these conclusions, the project provides new insight into the relationships between patient natural history, histopathology, and mechanical behavior that may be useful in the development of accurate methods for rupture risk evaluation.

References

References
1.
Ashton
,
H. A.
,
Buxton
,
M. J.
,
Day
,
N. E.
,
Kim
,
L. G.
,
Marteau
,
T. M.
,
Scott
,
R. A.
,
Thompson
,
S. G.
, and
Walker
,
N. M.
,
2002
, “
The Multicentre Aneurysm Screening Study (Mass) Into the Effect of Abdominal Aortic Aneurysm Screening on Mortality in Men: A Randomized Control Trial
,”
Lancet
,
360
, pp.
1531
1539
.
2.
Lederle
,
F. A.
,
Johnson
,
G. R.
,
Wilson
,
S. E.
,
Ballard
,
D. J.
,
Jordan
,
W. D.
, Jr.
,
Blebea
,
J.
,
Littooy
,
F. N.
,
Freischlag
,
J. A.
,
Bandyk
,
D.
,
Rapp
,
J. H.
, and
Salam
,
A. A.
,
2002
, “
Veterans Affairs Cooperative Study, I. Rupture Rate of Large Abdominal Aortic Aneurysms in Patients Refusing or Unfit for Elective Repair
,”
J. Am. Med. Assoc.
,
287
(
22
), pp.
2968
2972
.
3.
Karkos
,
C.
,
Mukhodpadhyay
,
U.
,
Papakostas
,
I.
,
Ghosh
,
J.
,
Thomson
,
G.
, and
Hughes
,
R.
,
2000
, “
Abdominal Aortic Aneurysm: The Role of Clinical Examination and Opportunistic Detection
,”
Eur. J. Vasc. Endovasc. Surg.
,
19
(
3
), pp.
299
303
.
4.
Davis
,
M.
,
Harris
,
M.
, and
Earnshaw
,
J. J.
,
2013
, “
Implementation of the National Health Service Abdominal Aortic Aneurysm Screening Program in England
,”
J. Vasc. Surg.
,
57
(
5
), pp.
1440
1445
.
5.
Lederle
,
F. A.
,
2009
, “
The Natural History of Abdominal Aortic Aneurysm
,”
Acta Chir. Belg.
,
109
(
1
), pp.
7
12
.
6.
CDC
,
2015
, “
National Center for Health Statistics
,” Centers for Disease Control and Prevention, Atlanta, GA, accessed, June 2015, www.cdc.gov/nchs/deaths.htm
7.
Grootenboer
,
N.
,
Bosch
,
J.
,
Hendriks
,
J. M.
, and
van Sambeek
,
M. R. H. M.
,
2009
, “
Epidemiology, Aetiology, Risk of Rupture and Treatment of Abdominal Aortic Aneurysms: Does Sex Matter?
,”
Eur. J. Vasc. Endovasc. Surg.
,
38
(
3
), pp.
278
284
.
8.
Lederle
,
F. A.
,
Wilson
,
S. E.
,
Johnson
,
G. R.
,
Reinke
,
D. B.
,
Littooy
,
F. N.
,
Acher
,
C. W.
,
Ballard
,
D. J.
,
Messina
,
L. M.
,
Gordon
,
I. L.
,
Chute
,
E. P.
,
Krupski
,
W. C.
,
Busuttil
,
S. J.
,
Barone
,
G. W.
,
Sparks
,
S.
,
Graham
,
L. M.
,
Rapp
,
J. H.
,
Makaroun
,
M. S.
,
Moneta
,
G. L.
,
Cambria
,
R. A.
,
Makhoul
,
R. G.
,
Eton
,
D.
,
Ansel
,
H. J.
,
Freischlag
,
J. A.
, and
Bandyk
,
D.
,
2002
, “
Immediate Repair Compared With Surveillance of Small Abdominal Aortic Aneurysms
,”
N. Engl. J. Med.
,
346
(
19
), pp.
1437
1444
.
9.
Nevitt
,
M. P.
,
Ballard
,
D. J.
, and
Hallett
,
J. W.
,
1989
, “
Prognosis of Abdominal Aortic Aneurysms: A Population Based Study
,”
N. Engl. J. Med.
,
321
(
15
), pp.
1009
1014
.
10.
Thompson
,
S.
,
Brown
,
L.
,
Sweeting
,
M.
,
Bown
,
M.
,
Kim
,
L.
,
Glover
,
M.
,
Buxton
,
M.
, and
Powell
,
J.
,
2013
, “
Systematic Review and Meta-Analysis of the Growth and Rupture Rates of Small Abdominal Aortic Aneurysms: Implications for Surveillance Intervals and Their Cost-Effectiveness
,”
Health Technol. Assess.
,
17
(41), pp.
1
118
.
11.
Fillinger
,
M. F.
,
Raghavan
,
M. L.
,
Marra
,
S. P.
,
Cronenwett
,
J. L.
, and
Kennedy
,
F. E.
,
2002
, “
In Vivo Analysis of Mechanical Wall Stress and Abdominal Aortic Aneurysm Rupture Risk
,”
J. Vasc. Surg.
,
36
(
3
), pp.
589
597
.
12.
Fillinger
,
M. F.
,
2007
, “
Who Should We Operate on and How Do We Decide: Predicting Rupture and Survival in Patients With Aortic Aneurysm
,”
Semin. Vasc. Surg.
,
20
(
2
), pp.
121
127
.
13.
Larsson
,
E.
,
Labruto
,
F.
,
Gasser
,
T.
,
Swedenborg
,
J.
, and
Hultgren
,
R.
,
2011
, “
Analysis of Aortic Wall Stress and Rupture Risk in Patients With Abdominal Aortic Aneurysm With a Gender Perspective
,”
J. Vasc. Surg.
,
54
(
2
), pp.
295
299
.
14.
Tong
,
J.
,
Cohnert
,
T.
,
Regitnig
,
P.
, and
Holzapfel
,
G. A.
,
2011
, “
Effects of Age on the Elastic Properties of the Intraluminal Thrombus and the Thrombus-Covered Wall in Abdominal Aortic Aneurysms: Biaxial Extension Behaviour and Material Modelling
,”
Eur. J. Vasc. Endovasc. Surg.
,
42
(
2
), pp.
207
219
.
15.
Dorfmann
,
A.
,
Wilson
,
C.
,
Edgar
,
E. S.
, and
Peattie
,
R. A.
,
2010
, “
Evaluating Patient-Specific Abdominal Aortic Aneurysm Wall Stress Based on Flow-Induced Loading
,”
Biomech. Model. Mechanobiol.
,
9
(
2
), pp.
127
139
.
16.
Ahamed
,
T.
,
Dorfmann
,
L.
, and
Ogden
,
R. W.
,
2016
, “
Modelling of Residually Stressed Materials With Application to AAA
,”
J. Mech. Behav. Biomed. Mater.
,
61
, pp.
221
234
.
17.
Campa
,
J. S.
,
Greenhalgh
,
R. M.
, and
Powell
,
J. T.
,
1987
, “
Elastin Degradation in Abdominal Aortic Aneurysms
,”
Atherosclerosis
,
65
, pp.
12
21
.
18.
Choke
,
E.
,
Cockerill
,
G.
,
Wilson
,
W. R. W.
,
Sayed
,
S.
,
Dawson
,
J.
,
Loftus
,
I.
, and
Thompson
,
M. M.
,
2005
, “
A Review of Biological Factors Implicated in Abdominal Aortic Aneurysm Rupture
,”
Eur. J. Vasc. Endovasc. Surg.
,
30
(
3
), pp.
227
244
.
19.
He
,
C. M.
, and
Roach
,
M. R.
,
1994
, “
The Composition and Mechanical Properties of Abdominal Aortic Aneurysm
,”
J. Vasc. Surg.
,
20
(
1
), pp.
6
13
.
20.
Summer
,
D. S.
,
Hokanson
,
D. S.
, and
Strandness
,
D. E. J.
,
1970
, “
Stress Strain Characteristics and Collagen Elastin Content of Abdominal Aortic Aneurysms
,”
Surg. Gynecol. Obstet.
,
130
(
3
), pp.
459
466
.
21.
McGee
,
G. S.
,
Baxter
,
B. T.
,
Shively
,
V. P.
,
Chisholm
,
R.
,
McCarthy
,
W. J.
,
Flinn
,
W. R.
,
Yao
,
J. S. T.
, and
Pearce
,
W. H.
,
1991
, “
Aneurysm or Occlusive Disease-Factors Determining the Clinical Course of Atherosclerosis of the Infrarenal Aorta
,”
Surgery
,
110
(
2
), pp.
370
376
.https://www.ncbi.nlm.nih.gov/pubmed/1858045
22.
Vorp
,
D. A.
,
2007
, “
Biomechanics of Abdominal Aortic Aneurysm
,”
J. Biomech.
,
40
(
9
), pp.
1887
1902
.
23.
Maier
,
A.
,
Gee
,
M. W.
,
Reeps
,
C.
,
Eckstein
,
H. H.
, and
Wall
,
W. A.
,
2010
, “
Impact of Calcifications on Patient-Specific Wall Stress Analysis of Abdominal Aortic Aneurysms
,”
Biomech. Model. Mechanobiol.
,
9
(
5
), pp.
511
521
.
24.
Buijs
,
R. V.
,
Willems
,
T. P.
,
Tio
,
R. A.
,
Boersma
,
H. H.
,
Tielliu
,
I. F.
,
Slart
,
R. H.
, and
Zeebregts
,
C. J.
,
2013
, “
Calcification as a Risk Factor for Rupture of Abdominal Aortic Aneurysm
,”
Eur. J. Vasc. Endovasc. Surg.
,
46
(
5
), pp.
542
548
.
25.
Vande Geest
,
J. P.
,
Sacks
,
M. S.
, and
Vorp
,
D. A.
,
2006
, “
The Effects of Aneurysm on the Biaxial Mechanical Behavior of Human Abdominal Aorta
,”
J. Biomech.
,
39
(
7
), pp.
1324
1334
.
26.
Tong
,
J.
,
Schriefl
,
A. J.
,
Cohnert
,
T.
, and
Holzapfel
,
G. A.
,
2013
, “
Gender Differences in Biomechanical Properties, Thrombus Age, Mass Fraction and Clinical Factors of Abdominal Aortic Aneurysms
,”
Eur. J. Vasc. Endovasc. Surg.
,
45
(
4
), pp.
364
372
.
27.
O'Leary
,
S. A.
,
Healey
,
D. A.
,
Kavanagh
,
E. G.
,
Walsh
,
M. T.
,
McGloughlin
,
T. M.
, and
Doyle
,
B. J.
,
2014
, “
The Biaxial Biomechanical Behavior of Abdominal Aortic Aneurysm Tissue
,”
Ann. Biomed. Eng.
,
42
(
12
), pp.
2440
2450
.
28.
Holzapfel
,
G. A.
,
Sommer
,
G.
, and
Regitnig
,
P.
,
2004
, “
Anisotropic Mechanical Properties of Tissue Components in Human Atherosclerotic Plaques
,”
ASME J. Biomech. Eng.
,
126
(
5
), pp.
657
665
.
29.
Abu-Farha
,
F.
,
Hector
,
L. G.
, Jr.
, and
Khraisheh
,
M.
,
2009
, “
Cruciform-Shaped Specimens for Elevated Temperature Biaxial Testing of Lightweight Materials
,”
J.O.M.
,
61
(8), pp.
48
56
.
30.
Waldman
,
S. D.
, and
Lee
,
J. M.
,
2005
, “
Effect of Sample Geometry on the Apparent Biaxial Mechanical Behaviour of Planar Connective Tissues
,”
Biomaterials
,
26
(
35
), pp.
7504
7513
.
31.
Pancheri
,
F. P.
, and
Dorfmann
,
A.
,
2014
, “
Strain Controlled Biaxial Tension of Natural Rubber: New Experimental Data
,”
Rubber Chem. Technol.
,
87
(
1
), pp.
120
138
.
32.
Hansen
,
F.
,
Bergqvist
,
D.
,
Mangell
,
P.
,
Rydén
,
A.
,
Sonesson
,
B.
, and
Länne
,
T.
,
1993
, “
Non-Invasive Measurement of Pulsatile Vessel Diameter Change and Elastic Properties Human Arteries: A Methodological Study
,”
Clin. Physiol.
,
13
(
6
), pp.
631
643
.
33.
Länne
,
T.
,
Stale
,
H.
,
Bengtsson
,
H.
,
Gustafsson
,
D.
,
Bergqvist
,
D.
,
Sonesson
,
B.
,
Lecerof
,
H.
, and
Dahl
,
P.
,
1992
, “
Noninvasive Measurement of Diameter Changes in the Distal Abdominal Aorta in Man
,”
Ultrasound Med. Biol.
,
18
(
5
), pp.
451
457
.
34.
ABAQUS, Inc
.,
2013
, “
Abaqus, Theory Manual
,” Dassault Systèmes Simulia, Waltham, MA, Version 6.13.
35.
Demiray
,
H.
,
1972
, “
A Note on the Elasticity of Soft Biological Tissues
,”
J. Biomech.
,
5
(
3
), pp.
309
311
.
36.
Holzapfel
,
G. A.
,
Gasser
,
T. C.
, and
Ogden
,
R. W.
,
2000
, “
A New Constitutive Framework for Arterial Wall Mechanics and a Comparative Study of Material Models
,”
J. Elasticity
,
61
, pp.
1
48
.
37.
Ogden
,
R. W.
,
1997
,
Non-Linear Elastic Deformations
,
Dover Publications
,
New York
.
38.
Pancheri
,
F. Q.
,
Eng
,
C. M.
,
Lieberman
,
D. E.
,
Biewener
,
A. A.
, and
Dorfmann
,
L.
,
2014
, “
A Constitutive Description of the Anisotropic Response of the Fascia Lata
,”
J. Mech. Behav. Biomed.
,
30
, pp.
306
323
.
39.
Pancheri
,
F. Q.
,
Eng
,
C. M.
,
Lieberman
,
D. E.
,
Biewener
,
A. A.
, and
Dorfmann
,
L.
,
2015
, “
Corrigendum to: A Constitutive Description of the Anisotropic Response of the Fascia Lata
,”
J. Mech. Behav. Biomed.
,
50
, pp.
308
310
.
40.
Buzzi-Ferraris
,
G.
, and
Manenti
,
F.
,
2009
, “
Kinetic Models Analysis
,”
Chem. Eng. Sci.
,
64
(
5
), pp.
1061
1074
.
41.
Junqueira
,
L. C.
, and
Carneiro
,
J.
,
2005
,
Basic Histology: Text & Atlas
,
11th ed.
,
McGraw-Hill Lange
,
New York
.
42.
Baxter
,
B. T.
,
Terrin
,
M. C.
, and
Dalman
,
R. L.
,
2008
, “
Medical Management of Small Abdominal Aortic Aneurysms
,”
Circulation
,
117
(
14
), pp.
1883
1889
.
43.
Wilmink
,
T. B. M.
,
Quick
,
C. R. G.
, and
Day
,
N. E.
,
1999
, “
The Association Between Cigarette Smoking and Abdominal Aortic Aneurysms
,”
J. Vasc. Surg.
,
30
(
6
), pp.
1099
1105
.
44.
Nagy
,
R.
,
Csobay-Novák
,
C.
,
Lovas
,
A.
,
Sótonyi
,
P.
, and
Bojtár
,
I.
,
2015
, “
Non-Invasive in vivo Time-Dependent Strain Measurement Method in Human Abdominal Aortic Aneurysms: Towards a Novel Approach to Rupture Risk Estimation
,”
J. Biomech.
,
48
(
10
), pp.
1876
1886
.
45.
Polzer
,
S.
,
Gasser
,
T. C.
,
Bursa
,
J.
,
Staffa
,
R.
,
Vlachovsky
,
R.
,
Man
,
V.
, and
Skacel
,
P.
,
2013
, “
Importance of Material Model in Wall Stress Prediction in Abdominal Aortic Aneurysms
,”
Med. Eng. Phys.
,
35
(
9
), pp.
1282
1289
.
46.
Gasser
,
T. D.
,
Gallinetti
,
S.
,
Xing
,
X.
,
Forsell
,
C.
,
Swedenborg
,
J.
, and
Roy
,
J.
,
2012
, “
Spatial Orientation of Collagen Fibers in the Abdominal Aortic Aneurysm's Wall and Its Relation to Wall Mechanics
,”
Acta Biomater.
,
8
(
8
), pp.
3091
3103
.
47.
Schulze-Bauer
,
C. A. J.
,
Morth
,
C.
, and
Holzapfel
,
G. A.
,
2003
, “
Passive Biaxial Mechanical Response of Aged Human Iliac Arteries
,”
ASME J. Biomech. Eng.
,
125
(
3
), pp.
395
406
.
48.
Sommer
,
G.
,
Regitnig
,
P.
,
Koeltringer
,
L.
, and
Holzapfel
,
G. A.
,
2010
, “
Biaxial Mechanical Properties of Intact and Layer-Dissected Human Carotid Arteries at Physiological and Supraphysiological Loadings
,”
Am. J. Physiol.-Heart C
,
298
(
3
), pp.
H898
H912
.
49.
Sommer
,
G.
, and
Holzapfel
,
G. A.
,
2012
, “
3D Constitutive Modeling of the Biaxial Mechanical Response of Intact and Layer-Dissected Human Carotid Arteries
,”
J. Mech. Behav. Biomed. Mater.
,
5
(
1
), pp.
116
128
.
50.
Reeps
,
C.
,
Maier
,
A.
,
Pelisek
,
J.
,
Härtl
,
F.
,
Grabher-Meier
,
V.
,
Wall
,
W. A.
,
Essler
,
M.
,
Eckstein
,
H. H.
, and
Gee
,
M. W.
,
2013
, “
Measuring and Modeling Patient-Specific Distributions of Material Properties in Abdominal Aortic Aneurysm Wall
,”
Biomech. Model. Mechanobiol.
,
12
(
4
), pp.
717
733
.
51.
Ogden
,
R. W.
,
Saccomandi
,
G.
, and
Sgura
,
I.
,
2004
, “
Fitting Hyperelastic Models to Experimental Data
,”
Comput. Mech.
,
34
(
6
), pp.
484
502
.
52.
Lindeman
,
J. H. N.
,
Ashcroft
,
B. A.
,
Beenakker
,
J. W. M.
,
van Es
,
M.
,
Koekkoek
,
N. B. R.
,
Prins
,
F. A.
,
Tielemans
,
J. F.
,
Abdul-Hussien
,
H.
,
Bank
,
R. A.
, and
Oosterkamp
,
T. H.
,
2010
, “
Distinct Defects in Collagen Microarchitecture Underlie Vessel-Wall Failure in Advanced Abdominal Aneurysms and Aneurysms in Marfan Syndrome
,”
Proc. Natl. Acad. Sci.
,
107
(
2
), pp.
862
865
.
53.
Wilson
,
K.
,
Lindholt
,
J.
,
Hoskins
,
P.
,
Heickendorff
,
L.
,
Vammen
,
S.
, and
Bradbury
,
A.
,
2001
, “
The Relationship Between Abdominal Aortic Aneurysm Distensibility and Serum Markers of Elastin and Collagen Metabolism
,”
Eur. J. Vasc. Endovasc. Surg.
,
21
(
2
), pp.
175
178
.
54.
Erhart
,
P.
,
Grond-Ginsbach
,
C.
,
Hakimi
,
M.
,
Lasitschka
,
F.
,
Dihlmann
,
S.
,
Böckler
,
D.
, and
Alexander Hyhlik-Dürr
,
A.
,
2014
, “
Finite Element Analysis of Abdominal Aortic Aneurysms: Predicted Rupture Risk Correlates With Aortic Wall Histology in Individual Patients
,”
J. Endovasc. Ther.
,
21
(
4
), pp.
556
564
.
55.
Rissland
,
P.
,
Alemu
,
Y.
,
Einav
,
S.
,
Ricotta
,
J.
, and
Bluestein
,
D.
,
2009
, “
Abdominal Aortic Aneurysm Risk of Rupture: Patient-Specific FSI Simulations Using Anisotropic Model
,”
ASME J. Biomech. Eng.
,
131
(
3
), p.
031001
.
56.
Raut
,
S. S.
,
Jana
,
A.
,
De Oliveira
,
V.
,
Muluk
,
S. C.
, and
Finol
,
E. A.
,
2013
, “
The Importance of Patient-Specific Regionally Varying Wall Thickness in Abdominal Aortic Aneurysm Biomechanics
,”
ASME J. Biomech. Eng.
,
135
(
8
), p.
81010
.
57.
Tierney
,
A. P.
,
Callanan
,
A.
, and
McGloughlin
,
T. M.
,
2012
, “
Use of Regional Mechanical Properties of Abdominal Aortic Aneurysms to Advance Finite Element Modeling of Rupture Risk
,”
J. Endovasc. Ther.
,
19
(
1
), pp.
100
114
.
58.
Polzer
,
S.
, and
Gasser
,
T. C.
,
2015
, “
Biomechanical Rupture Risk Assessment of Abdominal Aortic Aneurysm Based on a Novel Probabilistic Rupture Risk Index
,”
J. R. Soc. Interface
,
12
(
113
), p.
20150852
.
59.
Imura
,
T.
,
Yamamoto
,
K.
,
Kanamori
,
K.
,
Mikami
,
T.
, and
Yasuda
,
H.
,
1986
, “
Non-Invasive Ultrasonic Measurement of the Elastic Properties of the Human Abdominal Aorta
,”
Cardiovasc. Res.
,
20
(
3
), pp.
208
214
.
60.
Tavares Monteiro
,
J.
,
Simão da Silva
,
E.
,
Raghavan
,
M.
,
Puech-Leão
,
P.
,
Higuchi
,
M.
, and
Otoch
,
J.
,
2013
, “
Histologic, Histochemical, and Biomechanical Properties of Fragments Isolated From the Anterior Wall of Abdominal Aortic Aneurysms
,”
J. Vasc. Surg.
,
59
, pp.
1393
1401
.
61.
Vande Geest
,
J. P.
,
Wang
,
D. H. J.
,
Wisniewski
,
S. R.
,
Makaroun
,
M. S.
, and
Vorp
,
D. A.
,
2006
, “
Towards a Noninvasive Method for Determination of Patient-Specific Wall Strength Distribution in Abdominal Aortic Aneurysms
,”
Ann. Biomed. Eng.
,
34
(
7
), pp.
1098
1106
.
62.
Buijs
,
R. V.
,
Willems
,
T. P.
,
Tio
,
R. A.
,
Boersma
,
H. H.
,
Tielliu
,
I. F.
,
Slart
,
R. H.
, and
Zeebregts
,
C. J.
,
2013
, “
Calcification as a Risk Factor for Rupture of Abdominal Aortic Aneurysm
,”
Eur. J. Vasc. Endovasc. Surg.
,
46
(5), pp.
542
548
.
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