Fetal Endotracheal Occlusion (FETO) in the Resolution of Pulmonary Hypertension in Fetuses With Severe CDH

Congenital diaphragmatic hernia (CDH) occurs when the diaphragm fails to fully fuse and leaves a portal through which abdominal structures can migrate into the thorax. In the more severe cases, the abdominal structures remain in the thoracic cavity and compromise the development of the lungs. Infants born with this defect have a decreased capacity for gas exchange; mortality rates after birth have been reported between 40-60%. Now that CDH can be accurately diagnosed by mid-gestation, a number of strategies have been developed to repair the hernia and promote lung tissue development. Fetal tracheal occlusion (FETO), using a fetoscopically delivered and removed balloon device, has been used to temporarily occlude the trachea and increase lung distension in CDH to allow the lungs to develop and has been shown to increase survival at birth. The role of FETO in the resolution of pulmonary hypertension in fetuses with severe left- and right- sided CDH remains unclear. Our recent observation that FETO is associated with a higher proportion of infants who resolve their pulmonary hypertension by the age of 1 year as compared with those who have not had FETO, is based on a retrospective cohort study, which, as with any such design, has some intrinsic limitations. Thus, a prospective cohort study that is appropriately powered to confirm or disprove this encouraging observation is needed. If our preliminary observation is confirmed, resolution of PH by the age of 1 year could be added to the benefits of the FETO procedure in severe left and right-sided CDH cases. The investigators will perform 40 FETO procedures on fetuses diagnosed prenatally with severe right- or left-sided CDH, and outcome data will be compared with that of a control group of severe right- or left-sided CDH who will not undergo the FETO procedure because of medical or social issues. Because the prevalence of left-sided CDH is higher than right-side CDH, the investigators will perform 25 FETO procedures in left sided CDH and 15 in right-sided CDH, and these outcomes will be compared to a cohort of 40 non FETO cases.