title: Wall shear stress and flow patterns in the ascending aorta in patients with bicuspid aortic valves differ significantly from tricuspid aortic valves: a prospective study.
abstract: OBJECTIVE
  We compared flow and wall shear stress (WSS) patterns in the ascending aorta of individuals with either bicuspid aortic valve (BAV) or tricuspid aortic valve (TAV) using four-dimensional cardiovascular magnetic resonance (4D-CMR). BAV are known to be associated with dilation and dissection of the ascending aorta. However, the cause of vessel disease in patients with BAVs is unknown. Inborn connective tissue disease and also dilation secondary to increased WSS because of altered blood flow patterns in the ascending aorta are discussed as causes for dilation of the aorta. WSS can be estimated non-invasively by 4D-CMR.
  
  
  RESULTS
  Eighteen, otherwise, healthy individuals with functionally normal BAVs were compared prospectively with an age- and sex-matched control group of healthy individuals with TAV. Blood flow data were obtained by 4D-CMR visualization and WSS was calculated with specific software tools. Eighty-five per cent of the individuals with BAVs showed a high-grade helical flow pattern in the ascending aorta compared with 6% of the individuals with TAV. WSS in the ascending aorta was significantly altered in individuals with BAVs compared with TAV.
  
  
  CONCLUSIONS
  WSS and flow patterns in the ascending aorta in patients with BAVs without concomitant valve or vessel disease are significantly different compared with TAV. The significantly higher shear forces may have an impact on the development of aortic dilation in patients with BAVs.
authors.affiliation: Department of Pediatric Cardiology and Congenital Heart Disease, Technische Universität München, Lazarettstrasse 36, 80636 Munich, Germany. meierhofer@dhm.mhn.de
authors.forename: Christian
authors.initials: C
authors.lastname: Meierhofer
authors.forename: Eike Philipp
authors.initials: EP
authors.lastname: Schneider
authors.forename: Christine
authors.initials: C
authors.lastname: Lyko
authors.forename: Andrea
authors.initials: A
authors.lastname: Hutter
authors.forename: Stefan
authors.initials: S
authors.lastname: Martinoff
authors.forename: Michael
authors.initials: M
authors.lastname: Markl
authors.forename: Alfred
authors.initials: A
authors.lastname: Hager
authors.forename: John
authors.initials: J
authors.lastname: Hess
authors.forename: Heiko
authors.initials: H
authors.lastname: Stern
authors.forename: Sohrab
authors.initials: S
authors.lastname: Fratz
mesh_terms: D000293:Adolescent; D000328:Adult; D001011:Aorta / Q000000981:diagnostic imaging* / Q000502:physiology*; D001021:Aortic Valve / Q000002:abnormalities* / Q000000981:diagnostic imaging / Q000502:physiology; D000082882:Bicuspid Aortic Valve Disease; D001783:Blood Flow Velocity / Q000502:physiology*; D055424:Cardiac-Gated Imaging Techniques; D016022:Case-Control Studies; D002648:Child; D005260:Female; D006330:Heart Defects, Congenital / Q000000981:diagnostic imaging / Q000503:physiopathology; D006349:Heart Valve Diseases / Q000000981:diagnostic imaging*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D011446:Prospective Studies; D012984:Software; D014261:Tricuspid Valve / Q000000981:diagnostic imaging* / Q000502:physiology*; D014463:Ultrasonography