Postnatal acute renal failure after fetal exposure to angiotensin receptor blockers

Sustained activation of the renin-angiotensin-aldosteron system after fetal exposure to AT1 blockers: Effects on kidney and bone in a preterm newborn

The renin-angiotensin-aldosterone system (RAAS) plays a key role in development of fetal kidney. Angiotensin-converting enzyme (ACE) inhibitors or angiotensin II receptor type 1 (AT1) antagonists alter RAAS-signaling compromising metanephrogenesis, and vascular and tubular development. The result is a fetal "RAS blockage syndrome" that may occur not only following exposure during the second and third trimester, but also after the use of these drugs at the beginning of pregnancy. The in-utero exposure to AT1 antagonists is not confined exclusively to the risk of neonatal renal failure, but also to skull ossification defect that worsens the neonatal prognosis. We report the case of early arterial hypertension development, marked increase of plasma renin and aldosterone, severe hypocalvaria, and low bone mineralization in a female preterm infant in-utero exposed to AT1 antagonists.

Quantifying Proximal Collecting Tubule Deficiency in Angiotensin-Converting Enzyme Inhibitor and Angiotensin II Receptor Blocker Fetopathy

INTRODUCTION

Angiotensin-Converting Enzyme Inhibitors and Angiotensin II Receptor Blockers (AAs) are used for several indications, with cessation recommended in pregnancy due to toxic effects. AA fetopathy phenotype is similar to renal tubular dysgenesis including reduced proximal convoluted tubules (PCTs). Our study aimed to quantify the reduction of PCTs in fetuses and infants with prenatal exposure to AAs.

MATERIALS AND METHODS

We identified 5 fetal AA exposure cases that underwent autopsy at our institution between 2011 and 2018 and compared with 5 gestational age-matched controls. Immunohistochemistry with CD10 and epithelial membrane antigen (EMA) was utilized.

RESULTS

CD10 and EMA identified a median PCT density of 19.0% ± 12.3% in AA fetopathy patients, significantly less than controls (52.8% ± 4.4%; p < 0.0001). One case with in utero cessation had a PCT density of 34.2% ± 0.2%. Among other AA fetopathy findings, 1 case demonstrated unilateral renal vein thrombosis and 4 had hypocalvaria.

CONCLUSIONS

We have quantified the reduction in AA fetopathy PCT density, and demonstrated in utero cessation may recover PCT differentiation. Future studies may benefit from calculating PCT percentage as a potential biomarker to correlate with post-natal renal function and maternal factors including medication type, dosage, duration, and time from medication cessation.

Valsartan exposure in pregnancy with resultant anhydramnios and chronic kidney disease in a late preterm infant

In utero exposure to angiotensin II receptor blockers (ARBs) has fetotoxic effects including renal failure, oligohydramnios and lung hypoplasia. We present the case of a 24-year-old woman who presented to the maternity services in the 34th week of her first pregnancy. She was taking valsartan for hypertension. Ultrasound showed a structurally normal fetus with anhydramnios. The patient was admitted and valsartan was discontinued. She had spontaneous preterm delivery at 35 weeks' gestation of a baby girl. The baby's urine output was minimal in the first week of life and she was transferred to a paediatric hospital for specialist nephrology input. At 6 months of age, she requires ongoing nephrology follow-up and she remains on treatment for hypertension and anaemia. This case demonstrates the serious adverse effects resulting from ARB exposure in utero, and highlights the importance of avoiding fetotoxic medications in women of childbearing age.