EP06.73: Assessment of the severity of lung hypoplasia before fetoscopic endoluminal tracheal occlusion in fetuses affected by congenital diaphragmatic hernia using observed/expected total fetal lung volume

In fetuses with Congenital Diaphragmatic Hernia (CDH), ultrasound (US) measurement of observed/expected lung to head ratio (O/E LHR) is used as a proxy of lung size and to select candidates for Fetoscopic Endoluminal Tracheal Occlusion (FETO). Observed/expected Total Fetal Lung Volume (O/E TFLV) is another way to estimate fetal lung size based on lung volumes measured using MRI. The objective was to compare O/E TFLV against O/E LHR to predict survival in CDH fetuses who underwent FETO. Retrospective cohort study of 26 fetuses who underwent FETO for isolated severe or moderate CDH. All fetuses underwent US and MRI assessment at referral. O/E LHR was calculated from US scans and O/E TFLV with % of liver herniation were measured from MRIs. Based on US imaging, severe CDH (O/E LHR<25%) or moderate CDH (O/E LHR >=25% irrespectively of liver herniation) groups were created. O/E TFLV, percentage of liver herniation and 6 months survival were compared between “Severe” and “Moderate” CDH groups. Prediction of survival based on O/E TFLV and O/E LHR were evaluated using ROC curves. There were 9/26(34.6%) in the Severe CDH group. FETO was performed at 28.4[25.7-31.3] weeks and gestational age at delivery was 35.4[30.7-40.1] weeks. Survival at 6 months was 22/26(84.6%). O/E TFLV were similar between the Severe (25.95[14.6-30.8]%) and Moderate CDH group (25.86[12.4-32.3], p = 0.82). Percentage of liver herniation (32[18-43]% vs. 33[11.3-61]%, p = 0.94) and 6 months survival (severe: 8/9[88.9%] vs moderate: 14/17[82.4%], p = 1) were also similar. There was no significant difference in the prediction of survival between O/E TFLV (AUC = 0.75) and O/E LHR (AUC = 0.50, p = 0.14). Evaluation of fetal lung size using pre-FETO MRI scan O/E TFLV shows no differences with the predictive value of O/E LHR for 6 months survival.