Fetal Echocardiography and Hyperoxia Testing after Serial Amnioinfusions: Results from the RAFT Trial Bilateral Renal Agenesis Arm

Objective: Pulmonary hypoplasia and severe pulmonary hypertension associated with severe oligo/anhydramnios may be mitigated by amnioinfusion in fetal bilateral renal agenesis (BRA). We report fetal cardiovascular testing in liveborn BRA subjects of the Renal Anhydramnios Fetal Therapy (RAFT) Trial. Methods: Fetuses in the BRA RAFT trial cohort underwent third trimester echocardiography with maternal hyperoxia (MH). Echocardiographic parameters, compared between baseline and MH, are presented for expectant management and amnioinfusion participants using descriptive and inferential statistics. Results: Of 20 BRA pregnancies, 17 had amnioinfusions and 3 expectant management; 13 had fetal echocardiograms. Middle cerebral artery pulsatility index (PI) increased with MH (1.82 vs. 2.12, P=0.032), as tended umbilical artery PI (0.89 vs 1.02, P=0.056), without change in cardiac output or right ventricular percentage of the output, as expected. Fetuses in the intervention arm showed significant decrease in pulmonary artery PI; compared to no decrease or an increase in the control arm. All fetuses with clear reactivity had favorable respiratory status at 30 days of life. Minimal reactivity (<10%) was not predictive of poor outcome. Pulmonary artery branch dimensions were significantly larger in the treated fetuses. Conclusions: Fetal echocardiography with MH provides antenatal evidence of rescued pulmonary phenotype in BRA fetuses undergoing serial percutaneous amnioinfusions.