Morphometric study on pulmonary arterial thickness in pulmonary hypoplasia.

This study addresses the question of whether pulmonary hypoplasia is associated with structural changes of the pulmonary arteries. Quantitative (medial thickness, external radius) and qualitative (airway level) parameters of pulmonary arteries were assessed in eight hypoplastic lungs and eight lungs from age-matched fetuses without underlying primary pulmonary disease. The gestational ages ranged from 16 to 40 weeks. Relative medial thickness of the pulmonary arteries was related to the external radius and to the type of accompanying airway. Medial thickness was significantly higher in pulmonary hypoplasia than in normal fetal lungs. In contrast to normal fetal lungs, muscular arteries extended to the intra-acinar level in pulmonary hypoplasia. These arteries had medial thickness values up to a maximum of 80%.