Prenatal prediction of neonatal survival in cases diagnosed with congenital diaphragmatic hernia using abdomen-to-thorax ratio determined by ultrasonography

Aim The aim of this study was to evaluate the usefulness of abdomen-to-thorax ratio (ATR) measured by antenatal ultrasonography for predicting neonatal survival of fetuses with congenital diaphragmatic hernia (CDH). Material and Methods We identified 75 fetuses who were prenatally diagnosed with CDH and delivered in Seoul National University Hospital from 1998 to 2012, retrospectively. Of these, 40 cases who met the following criteria were included: (i) singleton pregnancy; (ii) a case that had available ultrasonographic images; and (iii) a neonate in whom follow-up until discharge from the hospital was available. ATR was measured as follows: each anteroposterior distance (APD) in the abdominal and thoracic cavity was measured in the same midsagittal plane with the fetal neutral position. A thoracic APD was measured from the back to the distal end of the sternum and an abdominal APD from the back to the most protruding abdominal surface. ATR is the ratio of the abdominal APD versus the thoracic APD. Results Survival rates were 57.5%. There were significant differences in ATR, lung-head ratio (LHR), observed/expected-LHR, quantitative lung index and intrathoracic liver between survivors and non-survivors. Regression analysis demonstrated that only ATR and intrathoracic position of the liver were independent predictors of survival. ATR by multivariate analysis had the most influence on survival rate (P= 0.002). The area under the receiver-operator curve for prediction of survival from ATR was 0.770 (P = 0.004). The diagnostic cut-off value for ATR was 0.96. Conclusions Because ATR is effective to predict neonatal survival in CDH fetuses and is easy to measure, it can be used as another powerful parameter for managing CDH fetuses.