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Agrafiotis, E; Mayer, C; Grabenwöger, M; Zimpfer, D; Regitnig, P; Mächler, H; Holzapfel, GA.
Global and local stiffening of ex vivo-perfused stented human thoracic aortas: A mock circulation study.
Acta Biomater. 2023; 161:170-183 Doi: 10.1016/j.actbio.2023.02.028
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Führende Autor*innen der Med Uni Graz
Agrafiotis Emmanouil
Co-Autor*innen der Med Uni Graz
Mächler Heinrich
Mayer Christian
Regitnig Peter
Zimpfer Daniel
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Abstract:
The effects of thoracic endovascular repair (TEVAR) on the biomechanical properties of aortic tissue have not been adequately studied. Understanding these features is important for the management of endograft-triggered complications of a biomechanical nature. This study aims to examine how stent-graft implantation affects the elastomechanical behavior of the aorta. Non-pathological human thoracic aortas (n=10) were subjected to long-standing perfusion (8h) within a mock circulation loop under physiological conditions. To quantify compliance and its mismatch in the test periods without and with a stent, the aortic pressure and the proximal cyclic circumferential displacement were measured. After perfusion, biaxial tension tests (stress-stretch) were carried out to examine the stiffness profiles between non-stented and stented tissue, followed by a histological assessment. Experimental evidence shows: (i) a significant reduction in aortic distensibility after TEVAR, indicating aortic stiffening and compliance mismatch, (ii) a stiffer behavior of the stented samples compared to the non-stented samples with an earlier entry into the nonlinear part of the stress-stretch curve and (iii) strut-induced histological remodeling of the aortic wall. The biomechanical and histological comparison of the non-stented and stented aortas provides new insights into the interaction between the stent-graft and the aortic wall. The knowledge gained could refine the stent-graft design to minimize the stent-induced impacts on the aortic wall and the resulting complications. STATEMENT OF SIGNIFICANCE: Stent-related cardiovascular complications occur the moment the stent-graft expands on the human aortic wall. Clinicians base their diagnosis on the anatomical morphology of CT scans while neglecting the endograft-triggered biomechanical events that compromise aortic compliance and wall mechanotransduction. Experimental replication of endovascular repair in cadaver aortas within a mock circulation loop may have a catalytic effect on biomechanical and histological findings without an ethical barrier. Demonstrating interactions between the stent and the wall can help clinicians make a broader diagnosis such as ECG-triggered oversizing and stent-graft characteristics based on patient-specific anatomical location and age. In addition, the results can be used to optimize towards more aortophilic stent grafts.
Find related publications in this database (using NLM MeSH Indexing)
Humans - administration & dosage
Aorta, Thoracic - diagnostic imaging, pathology
Blood Vessel Prosthesis - administration & dosage
Blood Vessel Prosthesis Implantation - methods
Mechanotransduction, Cellular - administration & dosage
Endovascular Procedures - methods
Stents - administration & dosage
Aortic Aneurysm, Thoracic - pathology
Prosthesis Design - administration & dosage
Treatment Outcome - administration & dosage

Find related publications in this database (Keywords)
Endovascular repair
Compliance mismatch
Aortic stiffening
Histological remodelling
Biaxial extension test
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