Introduction: We sought to define the fetal hemodynamic patterns of late gestation human fetuses with a range of congenital heart malformations that present with neonatal cyanosis using magnetic resonance imaging.
Methods: Blood flow was measured in the major vessels of normal late gestation human fetuses and fetuses with cyanotic congenital heart disease using phase contrast MRI with metric optimized gating. Oxygen saturations were measured in the major vessels of a subset of late gestation normal human fetuses and fetuses with cyanotic congenital heart disease using vascular T2 mapping on a 1.5T MRI system.
Results: Flow data was obtained in 50 normal fetuses (mean GA: 36.7 weeks SD 1.0 weeks) and 127 fetuses with CHD (mean GA: 36.0 weeks SD 1.6 weeks). Oximetry data were obtained in 30 normal fetuses and 47 fetuses with CHD. Our findings include lower CVO in fetuses with CHD with single ventricle physiology, with the lowest CVO observed in fetuses with severe forms of Ebstein’s Anomaly (EA). SVC flow was elevated in fetuses with transposition and reduced in fetuses with EA. Fetuses with left heart obstruction such as hypoplastic left heart syndrome have lower AAo flow and higher MPA and DA flow, while fetuses with right heart obstruction such as tetralogy of Fallot (TOF) and tricuspid atresia (TA) with ventriculo-arterial concordance have higher AAo flow and lower MPA and DA flow. Umbilical venous oxygen saturations (SaO2) are lower in patients with HLHS, TGA and TOF, while both ascending aortic and superior vena caval SaO2 are lower in all of the CHD types studied.
Conclusion: Congenital cardiac malformations result in significant changes in circulatory physiology which may account for some of the abnormalities in fetal development that have been described in newborns and fetuses with CHD.
Joshua Van Amerom– Research Analist, Division of Paediatric Cardiology, Hospital for Sick Children, University of Toronto
Davide Marini– Cardiologist, Division of Cardiology, Hospital for Sick Children and University of Toronto
Brahmdeep Saini– PhD Candidate, The Hospital for Sick Children and University of Toronto
Jessie Mei Lim– PhD Candidate, Division of Paediatric Cardiology, Hospital for Sick Children, University of Toronto
Edgar Jaeggi– Cardiologist, Division of Paediatric Cardiology, Hospital for Sick Children, University of Toronto
John Kingdom– Obstetrician, Maternal-Fetal Medicine, Mount Sinai Hospital and Obstetrics and Gynaecology, University of Toronto
Christopher Macgowan– Senior Scientist, Translational Medicine, Hospital for Sick Children and Department of Medical Biophysics, University of Toronto
Mike Seed– Division Head, Cardiology, Division of Cardiology, Hospital for Sick Children and Department of Paediatrics, University of Toronto