Fetal pulmonary artery stiffness is a strong predictor of persistent pulmonary hypertension of the newborn - An echocardiographic study.

Objective: Pulmonary artery stiffness (PAS) is a strong and independent predictor of mortality in adult patients with pulmonary hypertension (PH). But the change in PAS during perinatal period remains unknown. Here, we aimed to explore the feasibility and performance of PAS on predicting persistent pulmonary hypertension of the newborn (PPHN).

Methods: 1325 fetuses underwent a dedicated echocardiography screening for fetal heart defects during second trimester, third-trimester and neonatal period with the measurement of acceleration time (PAAT) and maximal frequency shift (MFS) of pulmonary artery flow. PAS (MFS/PAAT ratio) was calculated.

Results: Six fetuses were diagnosed as PPHN. Compared with the normal fetuses, those with PH had greater values of PAS during each period of time (second trimester, 52.6(46.2-54.5) vs. 32.4(28.0-39.4) kHz/s, p = 0.0003; third trimester, 52.9(46.1-55.3) vs. 29.7(27.3-33.3) kHz/s, p = 0.0002; neonatal period, 127.4(85.2-150.8) vs. 26.6(22.7-35.0) kHz/s, p < 0.0001). There was a statistically significant correlation between PAS and mean pulmonary artery pressure (p < 0.05) but no correlation between PAS and gestational age (p > 0.05) whether in normal fetuses or not. The area under receiver operating characteristic curve (AUC) of 0.97 for PAS during third trimester was superior to that for PAS during second trimester (AUC, 0.94) in predicting PPHN. The optimal cutoff value of PAS during third trimester was 37.40 KHz/s, with a sensitivity of 100%, a specificity of 91%, and an accuracy of 92%.

Conclusion: There was a significant difference in PAS between normal fetuses and those with PH. PAS has a power performance on predicting PPHN.