title: Characterization of CMR-derived haemodynamic data in children with pulmonary arterial hypertension.
abstract: OBJECTIVE
  Paediatric pulmonary arterial hypertension (PAH) is manifested as increased arterial pressure and vascular resistive changes followed by progressive arterial stiffening. The aim of this study was to characterize regional flow haemodynamic patterns and markers of vascular stiffness in the proximal pulmonary arteries of paediatric PAH patients, and to explore the association with right ventricular (RV) function.
  
  
  RESULTS
  Forty paediatric PAH patients and 26 age- and size-matched controls underwent cardiac magnetic resonance studies in order to compute time-resolved wall shear stress metrics, oscillatory shear index (OSI), and vascular strain as measured by relative area change (RAC), and RV volumetric and functional parameters. Phase-contrast imaging planes were positioned perpendicular to the mid-main and right pulmonary arteries (MPA and RPA, respectively). Compared with controls, the PAH group had decreased systolic wall shear stress (dyne cm-2) and RAC (%) in both MPA (WSSsys: 6.5 vs. 4.3, P < 0.0001; RAC: 36 vs. 25, P < 0.0001) and RPA (WSSsys: 11.2 vs. 7.3, P < 0.0001; strain: 37 vs. 30, P < 0.05). The OSI was significantly higher in the MPA of PAH subjects (0.46 vs. 0.17, P < 0.05). WSS measured in the MPA correlated positively with RAC (r = 0.63, P < 0.0001) and RV ejection fraction (%) (r = 0.63, P < 0.0001).
  
  
  CONCLUSIONS
  Wall shear stress, the principal haemodynamic force driving endothelial functional changes, is severely decreased in paediatric PAH patients and correlates with increased stiffness in the proximal pulmonary vasculature and reduced RV function.
authors.affiliation: Department of Pediatrics, Section of Cardiology, Children's Hospital Colorado, Denver-Aurora, CO, USA.|Department of Bioengineering, University of Colorado, Research 2 - Building P15, Anschutz Medical Campus, 12700 E 19th Avenue, Aurora, CO 80045-2560, USA.
authors.forename: Michal
authors.initials: M
authors.lastname: Schäfer
authors.affiliation: Department of Pediatrics, Section of Cardiology, Children's Hospital Colorado, Denver-Aurora, CO, USA.
authors.forename: D Dunbar
authors.initials: DD
authors.lastname: Ivy
authors.affiliation: Department of Radiology, Northwestern University, Chicago, IL, USA.
authors.forename: Alex J
authors.initials: AJ
authors.lastname: Barker
authors.affiliation: Department of Bioengineering, University of Colorado, Research 2 - Building P15, Anschutz Medical Campus, 12700 E 19th Avenue, Aurora, CO 80045-2560, USA.
authors.forename: Vitaly
authors.initials: V
authors.lastname: Kheyfets
authors.affiliation: Department of Bioengineering, University of Colorado, Research 2 - Building P15, Anschutz Medical Campus, 12700 E 19th Avenue, Aurora, CO 80045-2560, USA.
authors.forename: Robin
authors.initials: R
authors.lastname: Shandas
authors.affiliation: Department of Pediatrics, Section of Pulmonology, Children's Hospital Colorado, Denver-Aurora, CO, USA.
authors.forename: Steven H
authors.initials: SH
authors.lastname: Abman
authors.affiliation: Department of Pediatrics, Section of Cardiology, Children's Hospital Colorado, Denver-Aurora, CO, USA.|Department of Bioengineering, University of Colorado, Research 2 - Building P15, Anschutz Medical Campus, 12700 E 19th Avenue, Aurora, CO 80045-2560, USA.
authors.forename: Kendall S
authors.initials: KS
authors.lastname: Hunter
authors.affiliation: Department of Pediatrics, Section of Cardiology, Children's Hospital Colorado, Denver-Aurora, CO, USA.|Department of Bioengineering, University of Colorado, Research 2 - Building P15, Anschutz Medical Campus, 12700 E 19th Avenue, Aurora, CO 80045-2560, USA.
authors.forename: Uyen
authors.initials: U
authors.lastname: Truong
mesh_terms: D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D003287:Contrast Media; D005260:Female; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D006976:Hypertension, Pulmonary / Q000000981:diagnostic imaging* / Q000401:mortality / Q000503:physiopathology; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D011379:Prognosis; D011652:Pulmonary Circulation / Q000502:physiology; D012016:Reference Values; D012720:Severity of Illness Index; D033081:Shear Strength; D013318:Stroke Volume / Q000502:physiology*; D015996:Survival Rate; D059289:Vascular Stiffness; D016278:Ventricular Function, Right
chemical_list: D003287:Contrast Media
keywords: paediatric pulmonary arterial hypertension; stiffness; wall shear stress