title: Abnormal myocardial blood flow in children with mild/moderate aortic stenosis.
abstract: OBJECTIVE
  To quantify myocardial blood flow in infants and children with mild or moderate aortic stenosis using adenosine-infusion cardiac magnetic resonance.
  
  
  BACKGROUND
  It is unclear whether asymptomatic children with mild/moderate aortic stenosis have myocardial abnormalities. In addition, cardiac magnetic resonance-determined normative myocardial blood flow data in children have not been reported.
  
  
  METHODS
  We studied 31 infants and children with either haemodynamically normal hearts (n=20, controls) or mild/moderate aortic stenosis (n=11). The left ventricular myocardium was divided into six segments, and the change in average segmental signal intensity during contrast transit was used to quantify absolute flow (ml/g/minute) at rest and during adenosine infusion by deconvolution of the tissue curves with the arterial input of contrast.
  
  
  RESULTS
  In all the cases, adenosine was well tolerated without complications. The mean pressure gradient between the left ventricle and the ascending aorta was higher in the aortic stenosis group compared with controls (24 versus 3 mmHg, p<0.001). Left ventricular wall mass was slightly higher in the aortic stenosis group compared with controls (65 versus 50 g/m², p<0.05). After adenosine treatment, both the absolute increase in myocardial blood flow (p<0.0001) and the hyperaemic flow significantly decreased (p<0.001) in children with mild/moderate aortic stenosis compared with controls.
  
  
  CONCLUSIONS
  Abnormal myocardial blood flow in children with mild/moderate aortic stenosis may be an important therapeutic target.
authors: 1Doernbecher Children's Hospital,Oregon Health & Science University,Portland,Oregon,United States of America.
authors: Erin
authors: E
authors: Madriago
authors: 1Doernbecher Children's Hospital,Oregon Health & Science University,Portland,Oregon,United States of America.
authors: Ronald
authors: R
authors: Wells
authors: 1Doernbecher Children's Hospital,Oregon Health & Science University,Portland,Oregon,United States of America.
authors: David J
authors: DJ
authors: Sahn
authors: 2Department of Surgery,Oregon Health & Science University,Portland,Oregon,United States of America.
authors: Brian S
authors: BS
authors: Diggs
authors: 1Doernbecher Children's Hospital,Oregon Health & Science University,Portland,Oregon,United States of America.
authors: Stephen M
authors: SM
authors: Langley
authors: 3Department of Anesthesiology,Oregon Health & Science University,Portland,Oregon,United States of America.
authors: Daniel J
authors: DJ
authors: Woodward
authors: 4Brigham and Women's Hospital,Harvard Medical School,Boston,Massachusetts,United States of America.
authors: Michael
authors: M
authors: Jerosch-Herold
authors: 1Doernbecher Children's Hospital,Oregon Health & Science University,Portland,Oregon,United States of America.
authors: Michael
authors: M
authors: Silberbach
mesh_terms: D000241:Adenosine / Q000008:administration & dosage*; D000293:Adolescent; D001024:Aortic Valve Stenosis / Q000150:complications*; D001783:Blood Flow Velocity; D002648:Child; D002675:Child, Preschool; D003287:Contrast Media; D003326:Coronary Circulation / Q000502:physiology*; D005260:Female; D006352:Heart Ventricles / Q000503:physiopathology*; D006801:Humans; D007223:Infant; D008297:Male; D016277:Ventricular Function, Left / Q000502:physiology*
chemical_list: D003287:Contrast Media; D000241:Adenosine
keywords: Congenital heart disease; aortic stenosis; contrast media; fibrosis; perfusion