Fetoscopic Endoluminal Tracheal Occlusion (FETO) for Severe Left Diaphragmatic Hernia (CDH)

Despite advances in prenatal diagnosis and postnatal therapies, including extracorporeal membrane oxygenation (ECMO), inhaled nitric oxide therapy, and ventilator strategies that minimize ventilator-induced lung injury, morbidity and mortality rates for babies with congenital diaphragmatic hernia (CDH) remain high. The survival relates to the degree of prenatal lung compression and the subsequent impairment of pulmonary function following delivery. Prenatal assessment by ultrasound or magnetic resonance imaging allows to estimate the severity by relating the circumference of the lung contralateral to the hernia to the fetal head circumference lung to head ratio (LHR) and by noting the degree of upward herniation of the liver. Based on the observed to expected lung to head ratio (O/E LHR), prenatally diagnosed congenital diaphragmatic hernia can be prognostically assessed. While overall survival of congenital diaphragmatic hernia is approximately 60%, an O/E LHR \<25% is associated with survival between 11-24%. The rationale for fetal therapy in severe congenital diaphragmatic hernia is to restore adequate lung growth for neonatal survival. Prenatal tracheal occlusion obstructs the normal egress of lung fluid during pulmonary development leading to increased lung tissue stretch, increased cell proliferation, and accelerated lung growth. European colleagues have developed intrauterine endoscopic techniques (fetoscopy) to position and remove endoluminal tracheal balloons in utero (fetoscopic endotracheal occlusion = FETO). Recently, the Belgium group published summary results of FETO showing an improved survival in 175 patients with isolated left CDH from 24% to 49%. We hypothesize that FETO can be performed and may increase survival and decrease morbidity when compared to standard prenatal care for the treatment of severe CDH in the most severe group of fetuses with left CDH (O/E LHR \< 30%). FETO therapy will be considered in two subgroups: those with and O/E LHR \<