title: Apparent Aortic Stiffness in Children With Pulmonary Arterial Hypertension: Existence of Vascular Interdependency?
abstract: Left ventricular dysfunction, mediated by ventricular interdependence, has been associated with negative outcomes in children with pulmonary arterial hypertension (PAH). Considering the dilation of the pulmonary arteries as a paramount sign of PAH, we hypothesized that the ascending aorta will present signs of apparent stiffness in children with PAH and that this effect may be because of mechanical interaction with the dilated main pulmonary artery (MPA).
  
  
  
  Forty-two children with PAH and 26 age- and size-matched controls underwent comprehensive cardiac magnetic resonance evaluation. Assessment of aortic stiffness was evaluated by measuring pulse wave velocity, aortic strain, and distensibility. Children with PAH had significantly increased pulse wave velocity in the ascending aorta (3.4 versus 2.3 m/s for PAH and controls, respectively;P=0.001) and reduced aortic strain (23% versus 29%;P<0.0001) and distensibility (0.47 versus 0.64%/mm Hg;P=0.02). Indexed MPA diameter correlated with pulse wave velocity (P=0.04) and with aortic strain (P=0.02). The ratio of MPA to aortic size correlated with pulse wave velocity (P=0.0098), strain (P=0.0099), and distensibility (P=0.015). Furthermore, aortic relative area change was associated with left ventricular ejection fraction (P=0.045) and ventricular-vascular coupling ratio (P=0.042).
  
  
  
  Pediatric PAH patients have increased apparent ascending aortic stiffness, which was strongly associated with the degree of MPA distension. We speculate that distension of the MPA may play a major role in limiting full aortic expansion during systole, which modulates left ventricular performance and impacts systemic hemodynamics in pediatric PAH.
authors.affiliation: From the Division of Cardiology, Heart Institute, Children's Hospital Colorado (M.S., D.D.I., B.F., K.S.H., U.T.), Department of Bioengineering, College of Engineering and Applied Sciences (M.S., D.D.I., V.K., K.S.H., U.T.), Division of Pulmonology, Breathing Institute, Children's Hospital Colorado (S.H.A.), and Department of Radiology, Children's Hospital Colorado (L.P.B.), University of Colorado Denver/Anschutz Medical Campus; and Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, IL (A.J.B.). michal.schafer@ucdenver.edu.
authors.forename: Michal
authors.initials: M
authors.lastname: Schäfer
authors.affiliation: From the Division of Cardiology, Heart Institute, Children's Hospital Colorado (M.S., D.D.I., B.F., K.S.H., U.T.), Department of Bioengineering, College of Engineering and Applied Sciences (M.S., D.D.I., V.K., K.S.H., U.T.), Division of Pulmonology, Breathing Institute, Children's Hospital Colorado (S.H.A.), and Department of Radiology, Children's Hospital Colorado (L.P.B.), University of Colorado Denver/Anschutz Medical Campus; and Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, IL (A.J.B.).
authors.forename: D Dunbar
authors.initials: DD
authors.lastname: Ivy
authors.affiliation: From the Division of Cardiology, Heart Institute, Children's Hospital Colorado (M.S., D.D.I., B.F., K.S.H., U.T.), Department of Bioengineering, College of Engineering and Applied Sciences (M.S., D.D.I., V.K., K.S.H., U.T.), Division of Pulmonology, Breathing Institute, Children's Hospital Colorado (S.H.A.), and Department of Radiology, Children's Hospital Colorado (L.P.B.), University of Colorado Denver/Anschutz Medical Campus; and Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, IL (A.J.B.).
authors.forename: Steven H
authors.initials: SH
authors.lastname: Abman
authors.affiliation: From the Division of Cardiology, Heart Institute, Children's Hospital Colorado (M.S., D.D.I., B.F., K.S.H., U.T.), Department of Bioengineering, College of Engineering and Applied Sciences (M.S., D.D.I., V.K., K.S.H., U.T.), Division of Pulmonology, Breathing Institute, Children's Hospital Colorado (S.H.A.), and Department of Radiology, Children's Hospital Colorado (L.P.B.), University of Colorado Denver/Anschutz Medical Campus; and Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, IL (A.J.B.).
authors.forename: Alex J
authors.initials: AJ
authors.lastname: Barker
authors.affiliation: From the Division of Cardiology, Heart Institute, Children's Hospital Colorado (M.S., D.D.I., B.F., K.S.H., U.T.), Department of Bioengineering, College of Engineering and Applied Sciences (M.S., D.D.I., V.K., K.S.H., U.T.), Division of Pulmonology, Breathing Institute, Children's Hospital Colorado (S.H.A.), and Department of Radiology, Children's Hospital Colorado (L.P.B.), University of Colorado Denver/Anschutz Medical Campus; and Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, IL (A.J.B.).
authors.forename: Lorna P
authors.initials: LP
authors.lastname: Browne
authors.affiliation: From the Division of Cardiology, Heart Institute, Children's Hospital Colorado (M.S., D.D.I., B.F., K.S.H., U.T.), Department of Bioengineering, College of Engineering and Applied Sciences (M.S., D.D.I., V.K., K.S.H., U.T.), Division of Pulmonology, Breathing Institute, Children's Hospital Colorado (S.H.A.), and Department of Radiology, Children's Hospital Colorado (L.P.B.), University of Colorado Denver/Anschutz Medical Campus; and Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, IL (A.J.B.).
authors.forename: Brian
authors.initials: B
authors.lastname: Fonseca
authors.affiliation: From the Division of Cardiology, Heart Institute, Children's Hospital Colorado (M.S., D.D.I., B.F., K.S.H., U.T.), Department of Bioengineering, College of Engineering and Applied Sciences (M.S., D.D.I., V.K., K.S.H., U.T.), Division of Pulmonology, Breathing Institute, Children's Hospital Colorado (S.H.A.), and Department of Radiology, Children's Hospital Colorado (L.P.B.), University of Colorado Denver/Anschutz Medical Campus; and Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, IL (A.J.B.).
authors.forename: Vitaly
authors.initials: V
authors.lastname: Kheyfets
authors.affiliation: From the Division of Cardiology, Heart Institute, Children's Hospital Colorado (M.S., D.D.I., B.F., K.S.H., U.T.), Department of Bioengineering, College of Engineering and Applied Sciences (M.S., D.D.I., V.K., K.S.H., U.T.), Division of Pulmonology, Breathing Institute, Children's Hospital Colorado (S.H.A.), and Department of Radiology, Children's Hospital Colorado (L.P.B.), University of Colorado Denver/Anschutz Medical Campus; and Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, IL (A.J.B.).
authors.forename: Kendall S
authors.initials: KS
authors.lastname: Hunter
authors.affiliation: From the Division of Cardiology, Heart Institute, Children's Hospital Colorado (M.S., D.D.I., B.F., K.S.H., U.T.), Department of Bioengineering, College of Engineering and Applied Sciences (M.S., D.D.I., V.K., K.S.H., U.T.), Division of Pulmonology, Breathing Institute, Children's Hospital Colorado (S.H.A.), and Department of Radiology, Children's Hospital Colorado (L.P.B.), University of Colorado Denver/Anschutz Medical Campus; and Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, IL (A.J.B.).
authors.forename: Uyen
authors.initials: U
authors.lastname: Truong
mesh_terms: D000293:Adolescent; D000367:Age Factors; D001011:Aorta / Q000000981:diagnostic imaging / Q000503:physiopathology*; D062186:Arterial Pressure; D001696:Biomechanical Phenomena; D006328:Cardiac Catheterization; D002648:Child; D004108:Dilatation, Pathologic; D005260:Female; D006801:Humans; D006976:Hypertension, Pulmonary / Q000175:diagnosis / Q000503:physiopathology*; D019028:Magnetic Resonance Imaging, Cine; D008297:Male; D011651:Pulmonary Artery / Q000000981:diagnostic imaging / Q000503:physiopathology*; D063177:Pulse Wave Analysis; D012189:Retrospective Studies; D013314:Stress, Mechanical; D013997:Time Factors; D059289:Vascular Stiffness; D016277:Ventricular Function, Left; D055815:Young Adult
keywords: aortic stiffness; heart rate; interdependency; pediatric pulmonary hypertension; pulse wave analysis