Fetal aortic stenosis and changes in amniotic fluid natriuretic peptides

Objective Natriuretic peptides, especially brain natriuretic peptide (BNP), have demonstrated great usefulness in pediatric and adult cardiology. We studied their usefulness, based on amniotic fluid concentrations, in an ovine model of fetal aortic stenosis and in response to fetal cardiac intervention. Study Design After their natural history was established with gestation (n = 18 fetuses), natriuretic peptide levels were measured in a fetal model of aortic stenosis (50-60 days; term, 148 days; n=9) and were correlated to the severity of fetal heart disease. Response to fetal cardiac intervention in 3 hydropic fetuses was also assessed. Significance was established with 2-sided paired t -tests at a probability value of Results Amniotic fluid BNP (but not atrial natriuretic peptide) concentrations were elevated significantly with aortic stenosis (181.9 ± 109.9 pg/mL vs 50.0 ± 40.5 pg/mL in control fetuses), especially if complicated with hydrops (283 ± 74.4 pg/mL), and were correlated positively with the severity of stenosis and left ventricle hypertrophy. In the 1 animal surviving fetal intervention, BNP levels normalized. Conclusion Amniotic fluid BNP concentrations correlate with the severity of fetal aortic stenosis.