Echocardiographic findings of pulmonary atresia or critical pulmonary stenosis and intact ventricular septum in utero

Abstract

Background: Neonates with right ventricular outflow obstruction and intact ventricular septum show serious hemodynamic problems, such as severe hypoxemia, congestive heart failure due to massive tricuspid regurgitation, respiratory distress related to huge pulmonary hypoplasia or ventricular dysfunction due to right ventricle-coronary communication. Recent advances in fetal diagnosis include many cases of in utero diagnosis of pulmonary atresia or critical pulmonary stenosis and intact ventricular septum.

Method: Among the fetuses examined from April 1994 to March 1998, five fetuses were found with pulmonary atresia (PA) or critical pulmonary stenosis (CPS). Fetal echocardiograms were reviewed to elucidate the accuracy of fetal information and the efficacy of fetal diagnosis in the perinatal management of patient with CPS or PA and intact ventricular septum.

Results: The five cases were divided into two groups: two with a very small right ventricle (group 1) and three with a tripartite right ventricle (group 2). Fetal cardiomegaly and right atrial dilatation were prominent in group 2, whereas cardiac sizes were normal in group 1. Serial fetal examination in one group 2 fetus revealed developing right ventricular hypertrophy in utero. All group 2 cases showed massive tricuspid regurgitation (TR). Estimated right ventricular pressures from TR always exceeded the systemic blood pressures of gestational age-matched neonates. Reversed flow through the ductus arteriosus was recorded in both groups and ductus-dependent pulmonary circulation after birth was anticipated. Patency of both tricuspid and pulmonary valves was difficult to recognize in utero, as was right ventricle-coronary artery communication. Four of the five cases were maternally transported and survived palliative and/or definitive intervention. One fetus with chromosomal abnormality was observed without intervention during infancy and received palliative surgery when she was two years old.

Conclusion: Fetal hemodynamic information was useful for making decisions not only after birth, but also in utero, and may eventually result in improving the prognosis of babies with PA/CPS. Serial observation of the fetuses with PA/CPS may also suggest the possible pathogenesis of PA/CPS in utero.