title: Altered aortic 3D hemodynamics and geometry in pediatric Marfan syndrome patients.
abstract: BACKGROUND
  Blood flow dynamics make it possible to better understand the development of aortopathy and cardiovascular events in patients with Marfan syndrome (MFS). Aortic 3D blood flow characteristics were investigated in relation to aortic geometry in children and adolescents with MFS.
  
  
  METHODS
  Twenty-five MFS patients (age 15.6 ± 4.0 years; 11 females) and 21 healthy controls (age 16.0 ± 2.6 years; 12 females) underwent magnetic resonance angiography and 4D flow CMR for assessment of thoracic aortic size and 3D blood flow velocities. Data analysis included calculation of aortic diameter and BSA-indexed aortic dimensions (Z-score) along the thoracic aorta, 3D mean systolic wall shear stress (WSSmean) in ten aortic segments and assessment of aortic blood flow patterns.
  
  
  RESULTS
  Aortic root (root), ascending (AAo) and descending (DAo) aortic size was significantly larger in MFS patients than healthy controls (Root Z-score: 3.56 ± 1.45 vs 0.49 ± 0.78, p < 0.001; AAo Z-score 0.21 ± 0.95 vs -0.54 ± 0.64, p = 0.004; proximal DAo Z-score 2.02 ± 1.60 vs 0.56 ± 0.66, p < 0.001). A regional variation in prevalence and severity of flow patterns (vortex and helix flow patterns) was observed, with the aortic root and the proximal DAo (pDAo) being more frequently affected in MFS. MFS patients had significantly reduced WSSmeanin the proximal AAo (pAAo) outer segment (0.65 ± 0.12 vs. 0.73 ± 0.14 Pa, p = 0.029) and pDAo inner segment (0.74 ± 0.17 vs. 0.87 ± 0.21 Pa, p = 0.021), as well as higher WSSmeanin the inner segment of the distal AAo (0.94 ± 0.14 vs. 0.84 ± 0.15 Pa, p = 0.036) compared to healthy subjects. An inverse relationship existed between pDAo WSSmeanand both pDAo diameter (R = -0.53, p < 0.001) and % diameter change along the pDAo segment (R = -0.64, p < 0.001).
  
  
  CONCLUSIONS
  MFS children and young adults have altered aortic flow patterns and differences in aortic WSS that were most pronounced in the pAAo and pDAo, segments where aortic dissection or rupture often originate. The presence of vortex flow patterns and abnormal WSS correlated with regional size of the pDAo and are potentially valuable additional markers of disease severity.
authors.affiliation: Department of Radiology, Feinberg School of Medicine, Northwestern University , Chicago, IL, USA. r.vanderpalen@lumc.nl.|Division of Pediatric Cardiology, Department of Pediatrics, Leiden University Medical Center, Albinusdreef 2, 2333, ZA, Leiden, The Netherlands. r.vanderpalen@lumc.nl.
authors.forename: Roel L F
authors.initials: RL
authors.lastname: van der Palen
authors.affiliation: Department of Radiology, Feinberg School of Medicine, Northwestern University , Chicago, IL, USA.
authors.forename: Alex J
authors.initials: AJ
authors.lastname: Barker
authors.affiliation: Department of Radiology, Feinberg School of Medicine, Northwestern University , Chicago, IL, USA.
authors.forename: Emilie
authors.initials: E
authors.lastname: Bollache
authors.affiliation: Department of Radiology, Feinberg School of Medicine, Northwestern University , Chicago, IL, USA.|Department of Cardiac Sciences, Stephenson Cardiac Imaging Centre, University of Calgary - Cumming School of Medicine, Calgary, AB, Canada.
authors.forename: Julio
authors.initials: J
authors.lastname: Garcia
authors.affiliation: Department of Medical Imaging, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Rose
authors.affiliation: Department of Radiology, Feinberg School of Medicine, Northwestern University , Chicago, IL, USA.|Department of Radiology, Academic Medical Center, Amsterdam, The Netherlands.
authors.forename: Pim
authors.initials: P
authors.lastname: van Ooij
authors.affiliation: Department of Pediatrics, Division of Pediatric Cardiology, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA.
authors.forename: Luciana T
authors.initials: LT
authors.lastname: Young
authors.affiliation: Division of Pediatric Cardiology, Department of Pediatrics, Leiden University Medical Center, Albinusdreef 2, 2333, ZA, Leiden, The Netherlands.
authors.forename: Arno A W
authors.initials: AA
authors.lastname: Roest
authors.affiliation: Department of Radiology, Feinberg School of Medicine, Northwestern University , Chicago, IL, USA.|Department of Biomedical Engineering, McCormick School; of Engineering, Northwestern University, Chicago, IL, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Markl
authors.affiliation: Department of Radiology, Feinberg School of Medicine, Northwestern University , Chicago, IL, USA.|Department of Pediatrics, Division of Pediatric Cardiology, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA.|Department of Pediatrics, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
authors.forename: Joshua D
authors.initials: JD
authors.lastname: Robinson
authors.affiliation: Department of Radiology, Feinberg School of Medicine, Northwestern University , Chicago, IL, USA.|Department of Medical Imaging, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA.|Department of Pediatrics, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
authors.forename: Cynthia K
authors.initials: CK
authors.lastname: Rigsby
mesh_terms: D000293:Adolescent; D000367:Age Factors; D001013:Aorta, Thoracic / Q000000981:diagnostic imaging* / Q000503:physiopathology; D001783:Blood Flow Velocity; D002318:Cardiovascular Diseases / Q000000981:diagnostic imaging* / Q000209:etiology / Q000503:physiopathology; D016022:Case-Control Studies; D002648:Child; D005260:Female; D006439:Hemodynamics; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D008382:Marfan Syndrome / Q000150:complications* / Q000175:diagnosis; D055420:Perfusion Imaging / Q000379:methods*; D011237:Predictive Value of Tests; D012039:Regional Blood Flow; D013314:Stress, Mechanical; D013997:Time Factors
keywords: 4D flow; Aorta hemodynamics; Aortic geometry; Children; Marfan syndrome