Pulmonary Vasoreactivity to Materno-Fetal Hyperoxygenation Testing in Fetuses with Hypoplastic Left Heart

The aim of the study was to describe the response of fetal lung vasculature to maternal hyperoxygenation (MH) in the case of prenatally diagnosed hypoplastic left heart (HLH) with intact or restrictive (IAS/RAS) and without restriction of the atrial septum. Furthermore, the ability of MH to differentiate between newborns with HLH who do not require immediate atrial septostomy and newborns who will undergo immediate left atrial septoplasty after birth was evaluated.

Cross-sectional prospective study of fetuses ≥ 26 weeks of gestation with prenatally diagnosed HLH. Lung perfusion (LP) was qualitatively assessed by color Doppler interrogation and LP was quantitatively measured using the pulsatility index for veins (PIV). Measurements were performed both with the mother breathing room air (LPRA) and after receiving 100% oxygen for 10 minutes (LPMH). The oxygen test was defined as positive if MH led to an increase in lung perfusion and as negative if MH did not lead to an increase.

A total number of 22 pregnancies with hypoplasia of the left heart structures were included. 6/20 cases presented with an intact or restrictive atrial septum (IAS/RAS). All of these fetuses presented with a reduced LPRA. MH led to an increase in LP in 2/6 cases. The overall 30-day-survival rate was 83.3% (5/6). In 14/20 fetuses an open septum was detected. 11 cases had a normal LPRA, and the LPRA was reduced in 3/14 fetuses. The overall 30-day-survival rate was 92.9% (13/14).

MH might be a useful adjunct in the assessment of pulmonary vasculopathy in fetuses with HLH.