On the Impact of Intraluminal Thrombus Mechanical Behavior in AAA Passive Mechanics
2015 (English)In: Annals of Biomedical Engineering, ISSN 0090-6964, E-ISSN 1521-6047, Vol. 43, no 9, 2253-2264 p.Article in journal (Refereed) Published
Intraluminal thrombus (ILT) is a pseudo-tissue that develops from coagulated blood, and is found in most abdominal aortic aneurysms (AAAs) of clinically relevant size. A number of studies have suggested that ILT mechanical characteristics may be related to AAA risk of rupture, even though there is still great controversy in this regard. ILT is isotropic and inhomogeneous and may appear as a soft (single-layered) or stiff (multilayered fibrotic) tissue. This paper aims to investigate how ILT constitution and topology influence the magnitude and location of peak wall stress (PWS). In total 21 patient-specific AAAs (diameter 4.2-5.4 cm) were reconstructed from computer tomography images and biomechanically analyzed using state-of-the-art modeling assumptions. Results indicated that PWS correlated stronger with ILT volume (rho = 0.44, p = 0.05) and minimum thickness of ILT layer (rho = 0.73, p = 0.001) than with maximum AAA diameter (rho = 0.05, p = 0.82). On average PWS was 20% (SD 12%) higher for FE models that used soft instead of stiff ILT models (p < 0.001). PWS location strongly correlated with sites of minimum ILT thickness in the section of maximum AAA diameter and was independent from ILT stiffness. In addition, ILT heterogeneity, i.e., the spatial composition of soft and stiff thrombus tissue, can considerably influence stress in the AAA wall. The present study is limited to identification of influential biomechanical factors, and how its findings translate to an AAA rupture risk assessment remains to be explored by clinical studies.
Place, publisher, year, edition, pages
2015. Vol. 43, no 9, 2253-2264 p.
Intra-luminal thrombus (ILT), Abdominal aortic aneurysm (AAA), Patient-specific, Image-based, Zero pressure geometry, FEA, Anisotropy
Other Mechanical Engineering
IdentifiersURN: urn:nbn:se:kth:diva-172662DOI: 10.1007/s10439-015-1267-xISI: 000358646600022PubMedID: 25636600ScopusID: 2-s2.0-84937532647OAI: oai:DiVA.org:kth-172662DiVA: diva2:850795
QC 201509022015-09-022015-08-272015-09-02Bibliographically approved