title: The impact of intraluminal thrombus failure on the mechanical stress in the wall of abdominal aortic aneurysms.
abstract: OBJECTIVE
  The role of the intraluminal thrombus (ILT) in abdominal aortic aneurysm (AAA) rupture is controversial, and it is still not clear if an ILT increases or decreases AAA rupture risk. Specifically, signs of bleeding in the ILT are considered to increase AAA rupture risk. To further explore this hypothesis, intact AAAs (n = 4) with clear signs of fissures in the ILT, identified by computed tomography angiography (CTA) were investigated.
  
  
  METHODS
  Two different cases of ILT fissuring were investigated, where (1) ILT fissures were extracted directly from the CTA data and (2) a hypothetical fissure was introduced in the otherwise-intact ILT tissue. Wall stress distributions were predicted based on detailed Finite Element (FE) models.
  
  
  RESULTS
  ILT fissures extracted from CTA data locally increase the mechanical stress in the underlying wall by up to 30%. The largest impact on wall stress was observed if the ILT crack reaches the aneurysm wall, or if it involves large parts of the ILT. By contrast, a concentric failure in the medial ILT, which does not reach the aneurysm wall, has almost no impact on wall stress distribution. Hypothetical ILT fissures that connect the lumen with the wall cause a twofold increase of the stress in the underlying wall.
  
  
  CONCLUSIONS
  ILT fissures increase the stress in the underlying wall, whereas regions other than that remain unaffected. If ILT fissures reach the wall or involve large parts of the ILT, the resulting increase in wall stress could possibly cause AAA rupture.
authors.affiliation: Department of Solid Mechanics, Brno University of Technology, Czech Republic. polzer@seznam.cz
authors.forename: S
authors.initials: S
authors.lastname: Polzer
authors.forename: T C
authors.initials: TC
authors.lastname: Gasser
authors.forename: J
authors.initials: J
authors.lastname: Swedenborg
authors.forename: J
authors.initials: J
authors.lastname: Bursa
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D017544:Aortic Aneurysm, Abdominal / Q000150:complications* / Q000000981:diagnostic imaging / Q000503:physiopathology; D001019:Aortic Rupture / Q000209:etiology* / Q000503:physiopathology; D001027:Aortography / Q000379:methods; D003198:Computer Simulation; D005260:Female; D020342:Finite Element Analysis; D006801:Humans; D008297:Male; D008955:Models, Cardiovascular; D011379:Prognosis; D018570:Risk Assessment; D013314:Stress, Mechanical; D013927:Thrombosis / Q000150:complications* / Q000000981:diagnostic imaging / Q000503:physiopathology; D014057:Tomography, X-Ray Computed