Fetal Surgery for Moderate Left Sided Congenital Diaphragmatic Hernia.

Isolated Congenital Diaphragmatic Hernia (CDH) can be diagnosed in the prenatal period, and remains associated with a 30 % chance of perinatal death and morbidity mainly because of pulmonary hypoplasia and pulmonary hypertension. In addition, in the survivors there is a high rate of morbidity with evidence of bronchopulmonary dysplasia in more than 70% of cases. The risk for these can be predicted prenatally by the ultrasonographic measurement of the observed/expected lung area to head circumference ratio (O/E LHR) which is a measure of pulmonary hypoplasia. Also position of the liver is predictive of outcome. The proposing consortium has developed a prenatal therapeutic approach, which consists of percutaneous fetoscopic endoluminal tracheal occlusion (FETO) with subsequent removal of the balloon. Both procedures are performed percutaneously, there is now experience with more than 150 cases and it has been shown to be safe for the mother. We have witnessed an improvement of survival in fetuses with a predicted chance of survival of less than 30% (referred to as fetuses with severe pulmonary hypoplasia; O/E LHR \<25% and liver herniation) to 55% on average. Also there is an apparent reduction in morbidity with the rate of bronchopulmonary dysplasia decreasing from the estimated rate of more than 70% to less than 40% in the same severity group. Further we have shown that results of FETO are predicted by LHR measurement prior to the procedure, so that better results can be expected in fetuses with larger lung size. Therefore we now aim to offer FETO to fetuses with moderate CDH (=O/E LHR 25-34.9%, irrespective of the liver position as well as O/E LHR 35-44.9% with intrathoracic herniation of the liver). When managed expectantly the estimated rate of postnatal survival is 55%. This trial will test whether temporary fetoscopic tracheal occlusion rather than expectant management during pregnancy, both followed by standardized postnatal management increases survival or