Evaluation of Normal Fetal Branch Pulmonary Artery Diameters Measured by Ultrasonography: A Comparison with Congenital Diaphragmatic Hernia

Abstract

Objective: The aim of this study was to examine the size of fetal branch pulmonary artery (PA) diameters in normal growth fetuses. Method: Fetal PA diameters were measured in 175 normal fetuses between 18 and 40 weeks of gestation from 2005 to 2006. In addition, 4 fetuses with left-sided congenital diaphragmatic hernia (CDH) from 2001 to 2006 were retrospectively reviewed. Branch PA diameters were measured from a cross-sectional image at the level of the three-vessel view (main PA, ascending aorta and superior vena cava) to demonstrate the long axis of both branch PAs whenever possible. Results: Both the left and right PA diameters were found to correlate strongly with the advancing gestational age (r = 0.78, p < 0.01, respectively). Left pulmonary artery to main pulmonary artery (LPA/MPA) ratio and right pulmonary artery to main pulmonary artery (RPA/MPA) ratio were calculated. These two parameters were almost constant throughout gestation. LPA in fetal left CDH was smaller than control. Both LPA/MPA and RPA/MPA were within the normal range in most cases. Conclusions: It is important to establish the normal range of branch PA diameters and it appears to be useful to compare the branch PA diameters in normal fetuses with that in cases of pulmonary hypoplasia.

Tricuspid Valve Dysplasia with Severe Tricuspid Regurgitation: Fetal Pulmonary Artery Size Predicts Lung Viability in the Presence of Small Lung Volumes

“…Pulmonary artery size in the fetus may be a better predictor of lung development and the potential for normal respiratory function than lung volume measurements alone, as recently demonstrated in patients with congenital diaphragmatic hernia [17,20] . In our case, initial blood gases revealed respiratory failure, likely as a consequence of small lung volumes.…”

Doppler Velocimetry of the Ductus Arteriosus in Normal Fetuses and Fetuses Suspected for Pulmonary Hypoplasia

“…Pulmonary blood flow represents approximately 15-20% of the cardiac output, and any increase in resistance in the pulmonary circuit will result in a shift of flow towards the duc- tus arteriosus to the descending aorta. If lung development is arrested and causes pulmonary hypoplasia, the development of the vascular bed may be impaired, which is associated with an increased pulmonary vascular resistance and reduced pulmonary arterial compliance [5][6][7][8][9][10][11][12][13] . However, different studies give contradictory results on whether there are typical Doppler patterns indicating pulmonary hypoplasia.…”

“…Postmortem studies suggest that pulmonary hypoplasia is also characterized by a decreased size of the pulmonary vascular bed, reduced vessel count per unit of lung tissue and increased muscularization in peripheral vessels. An increase in resistance in the pulmonary vascular bed will result in a shift of flow towards the ductus arteriosus, resulting in changes in pulmonary and ductal velocity waveforms [5][6][7][8][9][10][11][12][13] .…”

Impact of ductus arteriosus constriction and restrictive foramen ovale on global hemodynamics for term fetuses with d‐TGA

“…Overall, the 1D cardiovascular network consists of 85 vessels, including 49 arteries and 36 veins. The values of geometrical and mechanical properties of 1D vessels are taken from the published data 14–18 or scaled down from the adult data 19,20 with the allometric scaling law‐based approach, 21 as summarized in Table 1. The 1D Navier‐Stokes equations, which can integrate the interplay among vessel morphology (geometrical and mechanical properties), pulse wave propagation phenomena, and hemodynamics, are introduced to describe blood flows in the major vessels of the fetal CVS, such as 22 where A denotes the cross‐sectional area of the vessel, t the time, x the axial coordinate along the vessel, u the average axial velocity, p the average vessel internal pressure over the cross section, μ = 0.0035 Pa·s the blood viscosity, ρ = 1050 kg/m 3 the blood density, and ξ = 22 the viscous friction constant, respectively.…”