Significance of the pulmonary vascular bed in congenital heart disease. V. Lesions of the left side of the heart causing obstruction of the pulmonary venous return.

A microscopic study was made of the lungs of 18 patients with congenital malformations of the heart in which there was obstruction of pulmonary venous drainage. Alterations in various components of the pulmonary vascular bed and of the lung parenchyma were described and correlated with the clinical course and the type of malformation present. A quantitative evaluation of the pulmonary arterial thickening was made by determining the lumen:wall ratio of small vessels. The anatomic alterations found in these children were compared to those of adults with acquired mitral stenosis.