title: Local Diameter, Wall Stress, and Thrombus Thickness Influence the Local Growth of Abdominal Aortic Aneurysms.
abstract: To investigate the influence of the local diameter, the intraluminal thrombus (ILT) thickness, and wall stress on the local growth rate of abdominal aortic aneurysms.
  
  
  
  The infrarenal aortas of 90 asymptomatic abdominal aortic aneurysm (AAA) patients (mean age 70 years; 77 men) were retrospectively reconstructed from at least 2 computed tomography angiography scans (median follow-up of 1 year) and biomechanically analyzed with the finite element method. Each individual AAA model was automatically sliced orthogonally to the lumen centerline and represented by 100 cross sections with corresponding diameters, ILT thicknesses, and wall stresses. The data were grouped according to these parameters for comparison of differences among the variables.
  
  
  
  Diameter growth was continuously distributed over the entire aneurysm sac, reaching absolute and relative median peaks of 3.06 mm/y and 7.3%/y, respectively. The local growth rate was dependent on the local baseline diameter, the local ILT thickness, and for wall segments not covered by ILT, also on the local wall stress level (all p<0.001). For wall segments that were covered by a thick ILT layer, wall stress did not affect the growth rate (p=0.08).
  
  
  
  Diameter is not only a strong global predictor but also a local predictor of aneurysm growth. In addition, and independent of the diameter, the ILT thickness and wall stress (for the ILT-free wall) also influence the local growth rate. The high stress sensitivity of nondilated aortic walls suggests that wall stress peaks could initiate AAA formation. In contrast, local diameters and ILT thicknesses determine AAA growth for dilated and ILT-covered aortic walls.
authors.affiliation: Department of Civil Engineering, University of Calgary, Alberta, Canada gmartufi@ucalgary.ca.|Department of Solid Mechanics, Royal Institute of Technology, Stockholm, Sweden.
authors.forename: Giampaolo
authors.initials: G
authors.lastname: Martufi
authors.affiliation: Department of Vascular Surgery, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Moritz
authors.initials: M
authors.lastname: Lindquist Liljeqvist
authors.affiliation: Department of Cardiovascular Surgery, University Hospital of Liege, Belgium.
authors.forename: Natzi
authors.initials: N
authors.lastname: Sakalihasan
authors.affiliation: Division of Vascular and Endovascular Surgery, University of Perugia, Hospital S. M. Misericordia, Perugia, Italy.|Clinic for Vascular and Endovascular Surgery, Münster University Hospital, Münster, Germany.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Panuccio
authors.affiliation: Department of Vascular Surgery, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Rebecka
authors.initials: R
authors.lastname: Hultgren
authors.affiliation: Department of Vascular Surgery, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Joy
authors.initials: J
authors.lastname: Roy
authors.affiliation: Department of Solid Mechanics, Royal Institute of Technology, Stockholm, Sweden.
authors.forename: T Christian
authors.initials: TC
authors.lastname: Gasser
mesh_terms: D000368:Aged; D001012:Aorta, Abdominal; D017544:Aortic Aneurysm, Abdominal / Q000473:pathology*; D001019:Aortic Rupture; D000072226:Computed Tomography Angiography; D018450:Disease Progression; D005260:Female; D006801:Humans; D008297:Male; D013927:Thrombosis / Q000473:pathology*; D016896:Treatment Outcome
keywords: abdominal aortic aneurysm; aneurysm diameter; aneurysm growth; finite element analysis; intraluminal thrombus; mechanical stress; wall stress