Third-trimester percentage predicted lung volume and percentage liver herniation as prognostic indicators in congenital diaphragmatic hernia

Background: Over the last two decades, fetal imaging has greatly improved, and new prenatal imaging measurements have been developed to characterize congenital diaphragmatic hernia (CDH) severity.

Objective: To determine the best prenatal imaging predictor of postnatal CDH outcomes, including use of extracorporeal membrane oxygenation (ECMO) and in-hospital mortality, with particular attention to the percentage of liver herniation (%LH) as a predictor. Additionally, we sought to guide best practices across hospital systems including improved models of prenatal risk assessment.

Materials and methods: We conducted a retrospective review of infants with left CDH who were prenatally diagnosed. We analyzed prenatal imaging measurements including observed-to-expected (O/E) lung-to-head ratio (LHR) on US, percentage predicted lung volume (PPLV) on MRI, and O/E total fetal lung volume (TFLV) and %LH on MRI. We compared prenatal imaging characteristics for infants with (1) in-hospital postnatal mortality and (2) use of ECMO. Then we performed multivariate logistic regression to determine independent predictors of postnatal outcomes.

Results: We included 63 infants with a median gestation of 34 weeks at the time of prenatal MRI. Low O/E LHR (31.2 vs. 50, P < 0.0001), PPLV (14.7 vs. 22.6, P < 0.0001) and O/E TLFV (24.6 vs. 38.3, P < 0.0001) and high %LH (15.1 vs. 2.1, P = 0.0006) were associated with worse postnatal outcomes; however, only PPLV was predictive of survival and need for ECMO on multivariable analysis. PPLV survival to discharge model showed an area under the curve (AUC) of 0.93 (95% confidence interval [CI]: 0.86, 0.99), P < 0.0001; and an odds ratio of 68.7 (95% CI: 6.5-2,302), P = 0.003. PPLV need for ECMO model showed AUC = 0.87 (95% CI: 0.78, 0.96), P < 0.0001; and odds ratio = 20.1 (95% CI: 3.1-226.3), P = 0.011.

Conclusion: Low O/E LHR, PPLV and O/E TFLV and high %LH in the third trimester are associated with worse postnatal outcomes. PPLV most strongly predicted outcome using a logistic regression model. Percentage of liver herniation was not an independent predictor of outcomes.