The impact of fetal endoscopic tracheal occlusion in isolated left-sided congenital diaphragmatic hernia on left-sided cardiac dimensions

Objectives: Fetal endoscopic tracheal occlusion (FETO) is offered to fetuses with congenital diaphragmatic hernia (CDH) and severe lung hypoplasia to promote lung growth and may secondarily affect left heart growth. The effects of FETO on left heart hypoplasia (LHH) are not described post-CDH repair. Methods: A retrospective analysis was performed for fetuses with left-sided CDH who underwent FETO and severity-matched controls from 2007 to 2016 at our institution. Echocardiographic, ultrasound, and MRI data were reviewed. Left heart dimensions were assessed prenatally and postnatally. Primary clinical outcome evaluated was death. Results: Twelve FETO patients and 18 controls were identified. Fetal LHH was noted in both groups and worsened after FETO. Postnatal mitral valve dimensions were larger in the FETO group pre-CDH repair (P=.03). Post-CDH repair, mitral valve and left ventricular dimensions were not significantly different between groups (P=.79 and P=.63 respectively) while FETO aortic valve dimensions were smaller (P=.04). Extracorporeal membrane oxygenation use was lower in the FETO group. No associations were found between left heart dimensions and outcomes. Conclusion: Although increased lung growth was seen after FETO, fetal LHH persisted with relative normalization seen post-repair. Persistent LHH post-FETO could be secondary to a small contribution of pulmonary venous return to the fetal left heart and increased intrathoracic pressures post-FETO.