title: Low rate of prenatal diagnosis among neonates with critical aortic stenosis: insight into the natural history in utero.
abstract: OBJECTIVE
  To better understand the natural history and spectrum of fetal aortic stenosis (AS), we aimed to (1) determine the prenatal diagnosis rate of neonates with critical AS and a biventricular (BV) outcome, and (2) describe the findings at fetal echocardiography in patients diagnosed prenatally.
  
  
  METHODS
  A multicenter, retrospective study was performed on neonates who presented with critical AS and who were discharged with a BV outcome from 2000 to 2013. The prenatal diagnosis rate was compared with that reported for hypoplastic left heart syndrome (HLHS). We reviewed fetal echocardiographic findings in patients who were diagnosed prenatally.
  
  
  RESULTS
  In only 10 (8.5%) of 117 neonates with critical AS and a BV outcome was the diagnosis made prenatally, a rate significantly lower than that for HLHS in the contemporary era (82%; P < 0.0001). Of the 10 patients diagnosed prenatally, all had developed left ventricular dysfunction by a median gestational age of 33 (range, 28-35) weeks. When present, Doppler abnormalities such as retrograde flow in the aortic arch (n = 2), monophasic mitral inflow (n = 3) and left-to-right flow across the foramen ovale (n = 8) developed late in gestation (median 33 weeks).
  
  
  CONCLUSIONS
  The prenatal diagnosis rate of critical AS and a BV outcome among neonates is very low, probably owing to a relatively normal four-chamber view in mid-gestation with development of significant obstruction in the third trimester. The natural history contrasts with that of severe mid-gestation AS with evolving HLHS and suggests that the gestational timing of development of significant AS has an important impact on subsequent left-heart growth in utero.
authors.affiliation: Department of Cardiology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.
authors.forename: L R
authors.initials: LR
authors.lastname: Freud
authors.forename: A
authors.initials: A
authors.lastname: Moon-Grady
authors.forename: M C
authors.initials: MC
authors.lastname: Escobar-Diaz
authors.forename: N L
authors.initials: NL
authors.lastname: Gotteiner
authors.forename: L T
authors.initials: LT
authors.lastname: Young
authors.forename: D B
authors.initials: DB
authors.lastname: McElhinney
authors.forename: W
authors.initials: W
authors.lastname: Tworetzky
mesh_terms: D001024:Aortic Valve Stenosis / Q000175:diagnosis* / Q000196:embryology; D004562:Electrocardiography; D005260:Female; D005865:Gestational Age; D006340:Heart Rate, Fetal; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D011247:Pregnancy; D011263:Pregnancy Trimester, Third; D012189:Retrospective Studies; D016216:Ultrasonography, Prenatal; D014481:United States
keywords: aortic stenosis; aortic valvuloplasty; congenital heart disease; fetal cardiology; prenatal diagnosis