Objective: The aim of the study was to determine the utility of ultrasonographically recorded blood flow waveforms of the pulmonary artery in the diagnosis of pulmonary hypoplasia.
Study design: The normal values of the pulsatility index and peak systolic flow of pulmonary arterial blood velocity waveforms were determined in 300 uncomplicated single fetus pregnancies with well-established gestational ages between 24 and 40 weeks. We also measured the same parameters in 5 fetuses at high risk for development of severe pulmonary hypoplasia. We also determined the radial alveolar count and microvessel density, representing the extent of angiogenesis, in tissue specimens collected at autopsy from normal and hypoplastic lungs and stained both with hematoxylin and eosin and immunohistochemically for factor VIII.
Results: In healthy fetuses the pulsatility index values of both the right and left pulmonary arteries diminished significantly with advancing gestation, whereas the peak systolic velocity increased significantly with advancing gestation. In fetuses with pulmonary hypoplasia pulsatility index values were high and the peak systolic flow was significantly lower than in healthy fetuses. Histologic examination showed a lower radial alveolar count and poorer angiogenesis in fetuses with pulmonary hypoplasia than in healthy fetuses.
Conclusion: Doppler ultrasonographic determination of pulmonary artery blood velocity waveforms is a useful tool for the diagnosis of pulmonary hypoplasia.