Bilateral Renal Agenesis—Interpreting the RAFT Trial

Bilateral renal agenesis is historically considered to be universally fatal, due to pulmonary hypoplasia resulting from failure to maintain adequate amniotic fluid from fetal urine production in the first half of pregnancy. This fundamental dictum from perinatal-neonatal medicine has been challenged by the RAFT trial in this issue of JAMA. The authors performed a multicenter nonrandomized clinical trial of pregnancies complicated by bilateral renal agenesis and anhydramnios due to fetal anuria to assess whether the infants of participants who agreed to serial amnioinfusions initiated prior to 26 weeks’ gestation to promote lung development would survive to 14 days of life or longer and receive placement of dialysis access. Even before the RAFT trial results were published, there was controversy about serial amnioinfusions for fetal bilateral renal agenesis. A key concern has been whether the goal for survival benefit is worth the risks (eg, complications associated with prematurity, dialysis, life-limiting kidney disease). In the RAFT trial, study participants were assessed, treated, delivered, and followed up at 1 of 9 US fetal therapy centers. Of the 18 participants who underwent serial amnioinfusions, all delivered preterm, and 82% of neonates met the primary outcome of survival to at least 14 days and receipt of access to dialysis. However, of the survivors, only 35% (n = 6) survived to discharge; 2 died after discharge of infectious complications and cardiac arrest, respectively, and 3 had a stroke. There were no surviving neonates among the 3 participants who selected expectant management. The authors conclude that they were able to mitigate pulmonary hypoplasia, but at what cost?