Structural changes in the pulmonary arteries and veins in tetralogy of Fallot.

The pulmonary arteries or veins from 6 children with tetralogy of Fallot have been injected with a barium sulphate and gelatin mixture. The branching pattern of the airways, arteries, and veins was normal. At all ages quantitative studies showed a decrease in total lung volume and in both pulmonary artery and vein size. In the intra-acinar region small arteries and veins were increased in number but the alveolar number was decreased. The pulmonary arteries were relatively more muscular than normal as shown both by increased medial wall thickness and by extension of muscle into smaller vessels than is normal.