Association between intrapulmonary arterial Doppler parameters and degree of lung growth as measured by lung-to-head ratio in fetuses with congenital diaphragmatic hernia

Objectives To describe the association between the intrapulmonary circulation and the degree of lung growth in fetuses with congenital diaphragmatic hernia (CDH). Methods Thirty-six fetuses with isolated left CDH at 22-29 weeks of gestation were studied. four groups were defined according to lung-to-bead ratio (LHR), expressed as the ratio of observed to expected LHR for gestational age (O/E LHR). Pulsatility index (PI), peak systolic velocity (PSV), peak early-diastolic reversed flow (PEDRF), end-diastolic velocity (EDV), acceleration time (AT), time averaged velocity (TAV) and the ratio AT to ejection time (AT/ET) were measured in all fetuses in the proximal arterial branch of both lungs. For analysis, Doppler values were converted to Z-scores. Results It was possible to record all Doppler parameters from the contralateral lung of all CDH fetuses, and from the ipsilateral lung in 28 (77.7%). PEDRF significantly increased in relation to the decrease in O/E LHR in both lungs (contralateral: r = -0. 65, P = 0.01; ipsilateral: r = -0.43, P = 0.02). PI increased significantly with the reduction in O/E LHR but only on the side contralateral to the hernia (r = -0.55, P = 0.02). In the ipsilateral pulmonary artery, PI values showed a significant overall increase but no differences were observed among the O/E LHR groups. PSV, EDV and TA V were reduced in both lungs with respect to normal values, but no association was found with the O/E LHR. No changes in AT or AT/ET were observed in either lung. Conclusions PEDRF is quick and easy to calculate, and showed the strongest and most consistent correlation with O/E LHR. The association between PEDRF and LHR might be an additional parameter that could help to establish prognosis in fetuses with CDH. Copyright (c) 2008 ISUOG. Published by John Wiley & Sons, Ltd.