(979) Mind the gap: identifying opportunities for fetal intervention for congenital diaphragmatic hernia in Ireland

To identify potential cases for fetoscopic endoluminal tracheal occlusion (FETO) in a historical cohort of fetuses with congenital diaphragmatic hernia (CDH).

Study Design:

We conducted a retrospective observational cohort study of fetuses with CDH managed in a single tertiary center spanning 14 years (2008 to 2021). Following ethical approval, cases were identified and data extracted from a fetal anomaly register. Archived images were reviewed to calculate observed-to-expected lung-to-head (O/E LHR) ratio based on TOTAL trial criteria. Potential cases for FETO: (1) singleton gestation at diagnosis < 30wks; (2) moderate-to-severe O/E LHR ratio < 45%; and (3) absence of genetic or extra-thoracic anomalies.

Results:

65 fetuses with CDH were identified. Median gestation at diagnosis was 22.3wks (IQR 21.1-26.6), with 50 being diagnosed at < 30wks’ gestation. CDH was left-sided in 42 (84%), right-sided in 6 (12%) and bilateral in 2 (4%). Of the 48 with unilateral CDH, O/E LHR was calculated in 32 cases, of which 14 (44%) were moderate (liver-up in 4) and 9 (28%) severe (O/E LHR < 25%). Four cases were further excluded because of extra-thoracic (n=2) or known genetic anomalies (n=2), leaving 19 (29%) of the 65 fetuses potentially eligible for FETO.

Conclusion:

Approximately one-third of historical cases of CDH in our center would have been eligible for FETO. Inconsistent classification of severity of CDH and/or referral for fetal MRI, late diagnosis, and the absence of national data likely contributed to fewer identifiable cases. Standardization of anomaly screening, uptake of validated assessments of O/E LHR, and increasing awareness of FETO have led to increasing referral for CDH in our center over time. Global uptake of FETO in recent years presents an opportunity for further development of fetal intervention in Ireland. Establishing a National Clinical Referral Pathway for CDH with concentrated emerging expertise across fetal, neonatal and paediatric centers should aim to improve outcomes and ‘close the gap’.