Lung to head ratio in infants with congenital diaphragmatic hernia does not predict long term pulmonary hypertension.

PURPOSE: Lung-to-head ratio (LHR) has been used for antenatal evaluation of infants with congenital diaphragmatic hernia (CDH). We hypothesized that LHR was predictive of acute and chronic pulmonary hypertension in infants with CDH.

METHODS: Echocardiograms on all inborn infants with CDH (December 2001-March 2011) were reviewed. Echocardiograms at 1 and 3 months post-repair and most recent follow-up were assessed for presence of pulmonary hypertension (PAH). LHR, gestational age, birth weight, extracorporeal membrane oxygenation (ECMO), and death rate were obtained. Bivariate and multivariate analyses were performed.

RESULTS: 106 infants with CDH had LHR obtained at median 28 weeks gestation (median LHR=1.25 [range 0.4-5.3]). Median follow-up was 26.6 months (range 4.6-97.5). The long-term incidence of pulmonary hypertension was 16%. LHR was significantly associated with pulmonary hypertension at one month (p=0.0001) but not at 3 months (p=0.22) or long-term (p=0.54). LHR was predictive of ECMO use (p=0.01) and death (p=0.001).

CONCLUSIONS: The overall incidence of PAH in infants with CDH decreases over time. Prenatal LHR predicts PAH at one month but not long-term in infants with CDH. The ability for LHR to predict PAH at one month but not long term may suggest remodeling of the pulmonary vasculature over time.