title: Severe left heart obstruction with retrograde arch flow influences fetal cerebral and placental blood flow.
abstract: OBJECTIVE
  Decreased middle cerebral artery (MCA) pulsatility index (PI) is a marker of fetal brain-sparing in placental insufficiency and it is also found in fetuses with severe congenital heart disease. This study sought to explore the impact of anatomical subtypes in fetal heart disease on MCA-PI and head growth.
  
  
  METHODS
  We retrospectively reviewed fetal echocardiograms of pregnancies complicated by fetal hypoplastic left heart syndrome (HLHS; n = 42) with and without anatomic coarctation (n = 28 and n = 10, respectively), isolated severe aortic coarctation (n = 21), D-transposition of the great arteries (TGA; n = 11) and pulmonary outflow tract obstruction without forward flow across the pulmonary valve (POTO; n = 15), comparing observations with gestational age-matched controls (n = 89). No fetus had major extracardiac pathology or aneuploidy. MCA and umbilical artery (UA) PI, the cerebral placental ratio (CPR  =  MCA-PI/ UA-PI) and neonatal head circumference were obtained and expressed as Z-scores.
  
  
  RESULTS
  Lower MCA-PI, higher UA-PI and lower CPR were observed in fetal HLHS and isolated coarctation with reversed arch flow (n = 6) (P < 0.001) but not TGA, POTO or isolated coarctation with antegrade arch flow (n = 15) compared with controls. No difference was found between HLHS with anatomical coarctation and those without; however, MCA-PI correlated positively with neonatal head circumference in HLHS with reversed distal arch flow (r = 0.33, P < 0.05).
  
  
  CONCLUSIONS
  Severe left heart obstruction with reversed aortic arch flow is associated with altered fetal cerebral blood flow, and in these conditions, MCA-PI positively correlates with head growth. Anatomical arch obstruction itself may not be a contributing factor to altered MCA flow in fetal HLHS.
authors: Fetal & Neonatal Cardiology Program, Department of Pediatrics, Division of Cardiology, Women's & Children's Health Research Institute and Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, AB, Canada.
authors: Y
authors: Y
authors: Yamamoto
authors: N S
authors: NS
authors: Khoo
authors: P A
authors: PA
authors: Brooks
authors: W
authors: W
authors: Savard
authors: A
authors: A
authors: Hirose
authors: L K
authors: LK
authors: Hornberger
mesh_terms: D001013:Aorta, Thoracic / Q000473:pathology; D001017:Aortic Coarctation / Q000000981:diagnostic imaging / Q000473:pathology; D002560:Cerebrovascular Circulation / Q000502:physiology; D004452:Echocardiography; D005260:Female; D047109:Fetal Development / Q000502:physiology*; D005315:Fetal Diseases / Q000000981:diagnostic imaging / Q000473:pathology*; D005311:Fetal Hypoxia / Q000503:physiopathology; D006257:Head / Q000503:physiopathology*; D006801:Humans; D018636:Hypoplastic Left Heart Syndrome / Q000000981:diagnostic imaging / Q000473:pathology; D007231:Infant, Newborn; D020768:Middle Cerebral Artery / Q000000981:diagnostic imaging / Q000503:physiopathology*; D021041:Placental Circulation / Q000502:physiology; D011247:Pregnancy; D011673:Pulsatile Flow / Q000502:physiology*; D012189:Retrospective Studies; D014188:Transposition of Great Vessels / Q000000981:diagnostic imaging / Q000473:pathology
keywords: brain sparing; coarctation; fetal hemodynamics; hypoplastic left heart syndrome; middle cerebral artery flow