Fetal pulmonary artery diameters and their association with lung hypoplasia and postnatal outcome in congenital diaphragmatic hernia.

Objective: We hypothesized that fetal branch pulmonary artery (PA) diameters indirectly reflect lung mass and are associated with postnatal outcome in cases of isolated congenital diaphragmatic hernia (CDH).

Study Design: We retrospectively reviewed echocardiograms of fetuses with CDH, measuring branch PA diameters and other echocardiographic parameters. Antenatal parameters were correlated with postmortem lung weights in 5 fetuses after pregnancy termination. Fetal echocardiographic measures were correlated with outcome variables in 29 live-born infants with CDH to identify antenatal indices associated with postnatal death and respiratory morbidity.

Results: Antenatal branch PA size correlated with postmortem lung weights from 5 terminated fetuses (r = 0.87). In 26 cases of left CDH in which the fetus continued to term, the ipsilateral branch PA diameter was significantly smaller than the contralateral branch PA diameter at presentation (P <.001). In these fetuses, a larger contralateral PA diameter was associated with worse postnatal survival (P =.049). Among survivors with left CDH, the main PA z score and the discrepancy between right and left PA diameters correlated positively with duration of supplemental oxygen requirement (P =.019 and P =.022, respectively) and ventilation (P =.036 and P =.012, respectively). Serial antenatal studies in 8 of 10 cases revealed progressive ipsilateral PA hypoplasia.

Conclusion: Antenatal branch PA size correlates with postmortem lung weight. A larger contralateral PA, and significant branch PA discrepancy and larger main PA diameter, best correlate with postnatal death and respiratory morbidity, respectively. Progressive ipsilateral PA hypoplasia suggests progressive in utero lung hypoplasia in cases of CDH.