TY - JOUR
T1 - Quantifying stent-induced damage in coronary arteries by investigating mechanical and structural alterations
T2 - Quantifying stent-induced vascular damage
AU - Geith, Markus A
AU - Nothdurfter, Laurenz
AU - Heiml, Manuel
AU - Agrafiotis, Emmanouil
AU - Gruber, Markus
AU - Sommer, Gerhard
AU - Schratzenstaller, Thomas G
AU - Holzapfel, Gerhard A
N1 - Copyright © 2020 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
PY - 2020/10/15
Y1 - 2020/10/15
N2 - Vascular damage develops with diverging severity during and after percutaneous coronary intervention with stent placement and is the prevailing stimulus for in-stent restenosis. Previous work has failed to link mechanical data obtained in a realistic in vivo or in vitro environment with data collected during imaging processes. We investigated whether specimens of porcine right coronary arteries soften when indented with a stent strut shaped structure, and if the softening results from damage mechanisms inside the fibrillar collagen structure. To simulate the multiaxial loading scenario of a stented coronary artery, we developed the testing device 'LAESIO' that can measure differences in the stress-stretch behavior of the arterial wall before and after the indentation of a strut-like stamp. The testing protocol was optimized according to preliminary experiments, more specifically equilibrium and relaxation tests. After chemical fixation of the specimens and subsequent tissue clearing, we performed three-dimensional surface and second-harmonic generation scans on the deformed specimens. We analyzed and correlated the mechanical response with structural parameters of high-affected tissue located next to the stamp indentation and low-affected tissue beyond the injured area. The results reveal that damage mechanisms, like tissue compression as well as softening, fiber dispersion, and the lesion extent, are direction-dependent, and the severity of them is linked to the strut orientation, indentation pressure, and position. The findings highlight the need for further investigations by applying the proposed methods to human coronary arteries. Additional data and insights might help to incorporate the observed damage mechanisms into material models for finite element analyses to perform more accurate simulations of stent-implantations.
AB - Vascular damage develops with diverging severity during and after percutaneous coronary intervention with stent placement and is the prevailing stimulus for in-stent restenosis. Previous work has failed to link mechanical data obtained in a realistic in vivo or in vitro environment with data collected during imaging processes. We investigated whether specimens of porcine right coronary arteries soften when indented with a stent strut shaped structure, and if the softening results from damage mechanisms inside the fibrillar collagen structure. To simulate the multiaxial loading scenario of a stented coronary artery, we developed the testing device 'LAESIO' that can measure differences in the stress-stretch behavior of the arterial wall before and after the indentation of a strut-like stamp. The testing protocol was optimized according to preliminary experiments, more specifically equilibrium and relaxation tests. After chemical fixation of the specimens and subsequent tissue clearing, we performed three-dimensional surface and second-harmonic generation scans on the deformed specimens. We analyzed and correlated the mechanical response with structural parameters of high-affected tissue located next to the stamp indentation and low-affected tissue beyond the injured area. The results reveal that damage mechanisms, like tissue compression as well as softening, fiber dispersion, and the lesion extent, are direction-dependent, and the severity of them is linked to the strut orientation, indentation pressure, and position. The findings highlight the need for further investigations by applying the proposed methods to human coronary arteries. Additional data and insights might help to incorporate the observed damage mechanisms into material models for finite element analyses to perform more accurate simulations of stent-implantations.
KW - Coronary artery
KW - Damage mechanism
KW - Indentation test
KW - Mechanical properties
KW - Micro-structure
KW - Percutaneous coronary intervention
KW - Second-harmonic generation imaging
KW - Softening
KW - Stent
KW - Vascular injury
UR - http://www.scopus.com/inward/record.url?scp=85090933625&partnerID=8YFLogxK
U2 - 10.1016/j.actbio.2020.08.016
DO - 10.1016/j.actbio.2020.08.016
M3 - Article
C2 - 32858190
SN - 1878-7568
VL - 116
SP - 285
EP - 301
JO - Acta Biomaterialia
JF - Acta Biomaterialia
ER -