title: Ventricular outputs, central blood flow distribution and flow pattern through the aortic isthmus of fetuses with simple transposition of the great arteries.
abstract: Our objective was to determine the impact of simple transposition of the great arteries (TGA) on fetal left ventricular (LV) and right ventricular (RV) performances and central circulatory dynamics including the aortic isthmus.
  
  
  
  Ventricular stroke volumes were calculated as the product of the cross-sectional area of the corresponding semi-lunar valve and the flow velocity integral through these valves. Volume flow in ductus arteriosus (QDA ) was evaluated using the same technique. Flow through the lungs (QLUNGS ) was calculated by subtracting net QDA from flow in main pulmonary artery [net QDA = QDA minus retrograde ductus arteriosus (DA) diastolic flow]. Relative performance of each ventricle expressed as percentage of combined cardiac output was also indirectly assessed by the aortic isthmus systolic index (ISI) (nadir of incisura/peak systolic of the Doppler waveforms in the isthmus); the relation between ISI and QLUNGS was investigated.
  
  
  
  Fifty-one fetuses with TGA were compared with 74 normal controls matched for gestational age. TGA fetuses had higher QLV at T2 (58.6 ± 9.4% vs. 43.4 ± 5.0%, p < 0.001) and T3 (53.7 ± 8.9% vs. 43.9 ± 5.7%, p < 0.001). QLUNGS was higher in fetuses with TGA, in the second (50.4 ± 16.3% vs. 39.0 ± 16.8%, p = 0.007) and third trimesters of gestation (52.8 ± 22.0% vs. 37.1 ± 16.3%, p = 0.005). No difference was found between ISI values from normal and TGA groups. A significant inverse correlation was observed between ISI and QLUNGS (r = -0.55, p = 0.006).
  
  
  
  Central distribution of combined cardiac output of fetuses with simple TGA is characterized by a greater QLUNGS leading to a dominant LV. In prenatal TGA, changes in QLUNGS could be monitored by measuring ISI. The clinical importance of this last observation deserves further investigations.
authors.affiliation: Pediatric Cardiology, CHU Sainte-Justine, University of Montreal, Montreal, Quebec, Canada.|Pediatric Department, Hospital Center of Avignon, Avignon, France.
authors.forename: Julie
authors.initials: J
authors.lastname: Blanc
authors.affiliation: Pediatric Cardiology, CHU Sainte-Justine, University of Montreal, Montreal, Quebec, Canada.
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Fouron
authors.affiliation: Pediatric Cardiology, Karolinska Institute, Stockholm, Sweden.
authors.forename: Sven-Erik
authors.initials: SE
authors.lastname: Sonesson
authors.affiliation: Pediatric Cardiology, CHU Sainte-Justine, University of Montreal, Montreal, Quebec, Canada.|Pediatric Cardiology, Cardiological Hospital Louis-Pradel, Lyon, France.
authors.forename: Marie-Josée
authors.initials: MJ
authors.lastname: Raboisson
authors.affiliation: Pediatric Cardiology, King's College, London, UK.
authors.forename: Ian
authors.initials: I
authors.lastname: Huggon
authors.affiliation: Pediatric Cardiology, CHU Sainte-Justine, University of Montreal, Montreal, Quebec, Canada.
authors.forename: Roxanne
authors.initials: R
authors.lastname: Gendron
authors.affiliation: Pediatric Cardiology, CHU Sainte-Justine, University of Montreal, Montreal, Quebec, Canada.
authors.forename: Annie
authors.initials: A
authors.lastname: Berger
authors.affiliation: Pediatric Cardiology, CHU Sainte-Justine, University of Montreal, Montreal, Quebec, Canada.
authors.forename: Sophie
authors.initials: S
authors.lastname: Brisebois
mesh_terms: D001013:Aorta, Thoracic / Q000000981:diagnostic imaging / Q000503:physiopathology*; D001783:Blood Flow Velocity; D002302:Cardiac Output; D018618:Echocardiography, Doppler, Color; D005260:Female; D005318:Fetal Heart / Q000000981:diagnostic imaging / Q000503:physiopathology*; D006352:Heart Ventricles / Q000000981:diagnostic imaging / Q000503:physiopathology*; D006801:Humans; D011247:Pregnancy; D012189:Retrospective Studies; D014188:Transposition of Great Vessels / Q000000981:diagnostic imaging / Q000503:physiopathology*; D016216:Ultrasonography, Prenatal
keywords: Transposition of the great arteries; fetus; lungs flow; ventricular outputs