Survival of neonates born with kidney failure during the initial hospitalization

Bilateral renal agenesis: fetal intervention and outcomes

Bilateral renal agenesis (BRA) is a fetal anomaly which leads to anhydramnios and resultant pulmonary hypoplasia. Historically, this anomaly was universally fatal early in the neonatal period due to the severity of the associated lung disease. Over the last 30 years, innovations in fetal therapies-specifically, serial amnioinfusions-have led to instances of infant pulmonary survival and initiation of postnatal dialysis, raising the possibility that early neonatal death may not be inevitable. Amnioinfusions are not without risk, and maternal complications can include prelabor rupture of membranes, preterm labor, infection, and bleeding. The data detailing neonatal outcomes are still limited and actively being collected. Two case series and one non-randomized clinical trial have supplied most of the known outcome data for infants with BRA after prenatal amnioinfusion. Although there are survivors reported in the literature, mortality remains high, with many deaths in infancy due to dialysis-associated sepsis. In addition, previously unknown morbidities have been documented in these infants, including neurologic injury. These challenges, in addition to the mechanical difficulties of providing dialysis to extremely small infants, can result in significant burdens for patients and their caregivers and moral distress for the health care team. The present review aims to explain the pathophysiology of BRA, detail the historical context and rationale for serial amnioinfusions to treat the pulmonary insufficiency associated with BRA, describe the available data regarding outcomes of infants born following prenatal amnioinfusions, discuss ethical issues surrounding this fetal intervention, and describe critical aspects of prenatal counseling for patients considering the intervention.

An Ethical Analysis of Therapy for Severe Congenital Kidney and Urinary Tract Anomalies

Technological advancements before and after delivery have greatly altered the counseling of pregnant patients facing a fetal diagnosis of severe oligohydramnios or anhydramnios secondary to congenital anomalies of the kidneys and urinary tract. Once considered a nearly uniformly lethal abnormality, long-term survival may now be possible secondary to prenatal innovations aimed at restoring the amniotic fluid volume and the availability of more advanced neonatal dialysis techniques. However, these available therapies are far from perfect. The procedures are onerous for pregnant patients without a guarantee of success, and families must prepare themselves for the complex life-long medical care that will be necessary for surviving individuals. Multidisciplinary counseling is imperative to help pregnant individuals understand the complexity of these conditions and assist them in exercising their right to informed decision-making. Moreover, as with any developing field of medicine, providers must contend with ethical questions related to the treatment options, including questions regarding patient-hood, distributive justice, and the blurred lines between research, innovation, and standard care. These ethical questions are best addressed in a multidisciplinary fashion with consideration of multiple points of view from various subspecialties. Only by seeing the entirety of the picture can we hope to best counsel patients about these highly complex situations and help navigate the most appropriate care path.

Neonatal Survival After Serial Amnioinfusions for Bilateral Renal Agenesis: The Renal Anhydramnios Fetal Therapy Trial

Importance

Early anhydramnios during pregnancy, resulting from fetal bilateral renal agenesis, causes lethal pulmonary hypoplasia in neonates. Restoring amniotic fluid via serial amnioinfusions may promote lung development, enabling survival.

Objective

To assess neonatal outcomes of serial amnioinfusions initiated before 26 weeks' gestation to mitigate lethal pulmonary hypoplasia.

Design, Setting, and Participants

Prospective, nonrandomized clinical trial conducted at 9 US fetal therapy centers between December 2018 and July 2022. Outcomes are reported for 21 maternal-fetal pairs with confirmed anhydramnios due to isolated fetal bilateral renal agenesis without other identified congenital anomalies.

Exposure

Enrolled participants initiated ultrasound-guided percutaneous amnioinfusions of isotonic fluid before 26 weeks' gestation, with frequency of infusions individualized to maintain normal amniotic fluid levels for gestational age.

Main Outcomes and Measures

The primary end point was postnatal infant survival to 14 days of life or longer with dialysis access placement.

Results

The trial was stopped early based on an interim analysis of 18 maternal-fetal pairs given concern about neonatal morbidity and mortality beyond the primary end point despite demonstration of the efficacy of the intervention. There were 17 live births (94%), with a median gestational age at delivery of 32 weeks, 4 days (IQR, 32-34 weeks). All participants delivered prior to 37 weeks' gestation. The primary outcome was achieved in 14 (82%) of 17 live-born infants (95% CI, 44%-99%). Factors associated with survival to the primary outcome included a higher number of amnioinfusions (P = .01), gestational age greater than 32 weeks (P = .005), and higher birth weight (P = .03). Only 6 (35%) of the 17 neonates born alive survived to hospital discharge while receiving peritoneal dialysis at a median age of 24 weeks of life (range, 12-32 weeks).

Conclusions and Relevance

Serial amnioinfusions mitigated lethal pulmonary hypoplasia but were associated with preterm delivery. The lower rate of survival to discharge highlights the additional mortality burden independent of lung function. Additional long-term data are needed to fully characterize the outcomes in surviving neonates and assess the morbidity and mortality burden.

Trial Registration

ClinicalTrials.gov Identifier: NCT03101891.