title: Studying the expansion of small abdominal aortic aneurysms: is there a role for peak wall stress?
abstract: OBJECTIVE
  The aim of this paper was to study the characteristics of three distending small abdominal aortic aneurysms (AAAs), with an increase in maximal diameter from 5 to 5.5 cm or above.
  
  
  METHODS
  Peak Wall Stress (PWS) in the presence and absence of intraluminal thrombus (ILT) was evaluated in 3 cases of small AAAs (5 cm), at initial presentation and after their expansion, at maximum diameters ≥5.5 cm using finite element analysis. Furthermore, AAA sac volume (Vsac), the percentage volume of ILT (ILT%) and the percentage change of Vsac (ΔV%) and ILT (ILT%) were estimated and the location of PWS was recorded.
  
  
  RESULTS
  Two AAA expanded from 5cm to 5.5 cm in a period of 6 months after initial presentation, with increase of sac volume by 20% and 30%, respectively. The third AAA expanded to a diameter of 6.5 cm after a follow-up period of 13 months, with a subsequent increase in sac volume of 78%. The expansion of AAA max diameter did not correlate with differences in peak wall stress (PWS) values at the initial presentation, ranging from 20.5 to 21.3 Nt/cm2.
  
  
  CONCLUSIONS
  PWS values cannot solely serve as a predictive tool for small AAA expansion. Small AAA expansion seem to be a multifactorial process, not solely described by PWS values but rather by a combination of mechanical, hemodynamic and biological factors.
authors.affiliation: Department of Vascular Surgery, University of Crete Medical School, Heraklion, Greece.
authors.forename: E
authors.initials: E
authors.lastname: Georgakarakos
authors.forename: C
authors.initials: C
authors.lastname: Ioannou
authors.forename: Y
authors.initials: Y
authors.lastname: Papaharilaou
authors.forename: T
authors.initials: T
authors.lastname: Kostas
authors.forename: G
authors.initials: G
authors.lastname: Kozyrakis
authors.forename: A
authors.initials: A
authors.lastname: Katsamouris
mesh_terms: D001012:Aorta, Abdominal / Q000000981:diagnostic imaging / Q000503:physiopathology*; D017544:Aortic Aneurysm, Abdominal / Q000000981:diagnostic imaging / Q000503:physiopathology*; D001027:Aortography / Q000379:methods; D018450:Disease Progression; D020342:Finite Element Analysis; D006439:Hemodynamics; D006801:Humans; D008297:Male; D013314:Stress, Mechanical; D013927:Thrombosis / Q000503:physiopathology; D013997:Time Factors; D014057:Tomography, X-Ray Computed