Perinatal changes of right ventricle-pulmonary artery coupling and its value in predicting persistent pulmonary hypertension of the newborn.

Background: Right ventricle-pulmonary artery (RV-PA) coupling is an independent predictor of outcome in pulmonary arterial hypertension in adults. Here, we aimed to investigate the changes in RV-PA coupling during the perinatal period, and to evaluate its performance on predicting persistent pulmonary hypertension of the newborn (PPHN).

Methods: A total of 1196 fetuses underwent a dedicated echocardiography screening for foetal heart defects during second trimester (24-27 weeks' gestation), third trimester (34-37 weeks' gestation) and neonatal period (within 14 days after delivery) with the measurement of tricuspid annular plane systolic excursion (TAPSE) and mean pulmonary artery pressure (MPAP). The RV-PA coupling (TAPSE/MPAP ratio) was calculated.

Results: Six fetuses were diagnosed as persistent pulmonary hypertension of the newborn (PPHN). In normal fetuses, RV-PA coupling had been increasing from the second trimester to the third trimester and then to the neonatal period (0.12 ± 0.02 vs. 0.18 ± 0.05 vs. 0.23 ± 0.08 mm/mmHg, p < 0.05), while it had been decreasing during the same period of time in abnormal fetuses (0.18 ± 0.02 vs. 0.17 ± 0.02 vs. 0.17 ± 0.01 mm/mmHg, p < 0.05). There was a strong positive correlation between RV-PA coupling and gestational age (GA) in normal fetuses (r = 0.71, p < 0.0001). The area under receiver operating characteristic curve (AUC) of 0.989 for RV-PA coupling during second trimester was superior to that for RV-PA coupling during third trimester (AUC: 0.536) in predicting PPHN. The optimal cutoff value was 0.16 mm/mmHg, with a sensitivity of 100.00%, a specificity of 96.36% and an accuracy of 97.73%.

Conclusion: RV-PA coupling had close relation with GA in normal fetuses. It was a strong predictor of PPHN.