title: Increased ascending aortic wall stress in patients with bicuspid aortic valves.
abstract: BACKGROUND
  Patients with bicuspid aortic valves (BAV) are at increased risk of ascending aortic dilatation, dissection, and rupture. We hypothesized that ascending aortic wall stress may be increased in patients with BAV compared with patients with tricuspid aortic valves (TAV).
  
  
  METHODS
  Twenty patients with BAV and 20 patients with TAV underwent electrocardiogram-gated computed tomographic angiography. Patients were matched for diameter. The thoracic aorta was segmented, reconstructed, and triangulated to create a mesh. Utilizing a uniform pressure load of 120 mm Hg, and isotropic, incompressible, and linear elastic shell elements, finite element analysis was performed to predict 99th percentile wall stress.
  
  
  RESULTS
  For patients with BAV and TAV, aortic root diameter was 4.0 ± 0.6 cm and 4.0 ± 0.6 cm (p = 0.724), sinotubular junction diameter was 3.6 ± 0.8 cm and 3.6 ± 0.7 cm (p = 0.736), and maximum ascending aortic diameter was 4.0 ± 0.8 cm and 4.1 ± 0.9 cm (p = 0.849), respectively. The mean 99 th percentile wall stress in the BAV group was greater than in the TAV group (0.54 ± 0.06 MPa vs 0.50 ± 0.09 MPa), though this did not reach statistical significance (p = 0.090). When normalized by radius, the 99 th percentile wall stress was greater in the BAV group (0.31 ± 0.06 MPa/cm vs 0.27 ± 0.03 MPa/cm, p = 0.013).
  
  
  CONCLUSIONS
  Patients with BAV, regardless of aortic diameter, have increased 99 th percentile wall stress in the ascending aorta. Ascending aortic three-dimensional geometry may account in part for the increased propensity to aortic dilatation, rupture, and dissection in patients with BAV.
authors.affiliation: Department of Surgery, Hospital of the University of Pennsylvania, Philadelphia, PA, USA.
authors.forename: Derek P
authors.initials: DP
authors.lastname: Nathan
authors.forename: Chun
authors.initials: C
authors.lastname: Xu
authors.forename: Ted
authors.initials: T
authors.lastname: Plappert
authors.forename: Benoit
authors.initials: B
authors.lastname: Desjardins
authors.forename: Joseph H
authors.initials: JH
authors.lastname: Gorman
authors.forename: Joseph E
authors.initials: JE
authors.lastname: Bavaria
authors.forename: Robert C
authors.initials: RC
authors.lastname: Gorman
authors.forename: Krishnan B
authors.initials: KB
authors.lastname: Chandran
authors.forename: Benjamin M
authors.initials: BM
authors.lastname: Jackson
mesh_terms: D001013:Aorta, Thoracic / Q000000981:diagnostic imaging / Q000503:physiopathology*; D017545:Aortic Aneurysm, Thoracic / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology*; D001021:Aortic Valve / Q000002:abnormalities*; D018450:Disease Progression; D004452:Echocardiography; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D006349:Heart Valve Diseases / Q000150:complications / Q000151:congenital* / Q000503:physiopathology; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D014655:Vascular Resistance