Despite regular progress in neonatal intensive care, congenital diaphragmatic hernia (CDH) diagnosed antenatally is still associated with up to 80% mortality. It is impossible to predict which fetus with CDH will survive or not.
Objective: To identify reliable antenatal predictors of outcome and of pulmonary hypoplasia (PH) in fetuses with CDH.
Design: Retrospective study.
Setting: Paediatric intensive care unit of a university children's hospital.
Patients and methods: Antenatal parameters and presence of left ventricular hypoplasia in utero were compared retrospectively to outcome and to presence of PH in 32 consecutive newborn infants with antenatally diagnosed CDH. Antenatal parameters included: gestational age at diagnosis, herniated organs, associated malformations and presence of polyhydramnios. Size of the cardiac ventricles, the aorta (Ao) and the pulmonary artery (PA) were obtained by fetal echocardiography, from which we calculated a cardioventricular index (left ventricle/right ventricle, LV/RV) and a cardiovascular index (Ao/PA). Delivery was planned in order to provide ventilatory and hemodynamic management. In case of death, PH was assessed according to the following criteria: the lung weight/body weight index and the radial alveolar count. For statistical comparisons, patients were separated into two groups: the hypoplasia group (H) and the non-hypoplasia group (NH).
Results: Thirty-two pregnancies were delivered. Twenty-six newborns died (81%), 6 survived (19%). When comparing non-survivors to survivors, predictors of poor outcome were: mean gestational age at diagnosis (23 vs 28 weeks, p = 0.002), intrathoracic stomach (20 vs 1 s, p = 0.01) and associated malformations (6 vs 0). Cardiac ventricular disproportion, expressed by the LV/RV ratio, appeared to correlate well with a poor outcome (0.63 in non-survivors vs 0.93 in survivors, p = 0.03) and with PH (0.63 in the H group vs 0.95 in the NH group, p = 0.03).
Conclusions: Our study confirmed the factors for a poor prognosis associated with CDH previously described in the literature, but none with a consistent demonstration of accuracy. LV hypoplasia may be a more accurate predictor of outcome and of PH but it has to be assessed by prospective studies with larger samples. Further basic science and Doppler-flow studies may be helpful to understand the natural history and pathophysiology of LV hypoplasia in CDH.