To determine: 1) the prevalence of persistent pulmonary hypertension (PPH) and its impact on postnatal outcome in infants with congenital diaphragmatic hernia (CDH) undergoing standardized management; 2) correlations between pre- and postnatal indicators and the presence of (refractory) PPH early in life. Retrospective analysis of prospectively collected data on a consecutive cohort of prenatally diagnosed isolated, left-sided CDH managed at two tertiary centers (UZLeuven and BCNatal) between 2008 and 2018. The primary outcome was the presence of PPH and refractory PPH (RPPH) on postnatal day 1, 7, 14, 28 and at discharge. PPH was defined as suprasystemic pulmonary arterial pressure on postnatal echocardiography and/or a preductal-postductal saturation difference >10%. RPPH was defined as the need of >1 drug to treat PPH or additional extra corporeal membrane oxygenation. Logistic regression analysis was performed to investigate the correlation between PPH or RPPH and observed-to-expected lung-to-head ratio (o/e LHR), liver herniation, gestational age (GA) at delivery and survival at discharge. Of the 179 neonates managed, 128(71%) survived till discharge. The prevalence of PPH decreased over time, from 68%(d1), 45%(d7), 33% (d14), 17% (d28) and 7% at discharge (χ2 for trend: p< 0.0001). On d1, but not later, the occurrence of any form of PPH correlated with mortality independently from other parameters. Conversely, all but one neonate without PPH at d1 (n=56) survived till discharge. The presence of RPPH, but not PPH on d7 and d14 correlated also to mortality independently from other parameters (Table 1). Also o/eLHR inversely correlated with the occurrence of PPH and RPPH from d1 until d14 independently from the other perinatal variables (Table 2). The presence and severity of PPH predicts mortality independently from other perinatal variables within the first two weeks of life. A smaller O/E LHR is inversely correlated with the chance to develop PPH within two weeks of life.View Large Image Figure ViewerDownload Hi-res image Download (PPT)