The Pulmonary Vasculature in Complete Transposition of the Great Vessels, Judged from Lung Biopsies

Specimens of the lung taken for biopsy at operation on 80 patients with complete transposition of the great vessels were histologically studied in correlation with the clinical and hemodynamic data in these cases. In a group of 31 cases of intact ventricular septum and patent foramen ovale, the media of the pulmonary arteries was generally thinner than normal, and to a lesser extent that of the pulmonary veins was also, while the lumina of the vessels were wide. This was especially observed in cases in which the hematocrit was high. Possibly, this phenomenon is based on dilatation of the arteries and is related to the increased total blood volume. Intimal fibrosis, when observed, was suggestive of organized thrombi. In a group of 28 patients with ventricular septal defect and equal pressures in the left and right ventricles, there was generally marked medial hypertrophy and concentric intimal proliferation in the pulmonary arteries. In cases of pulmonic stenosis, on the other hand, the media of the pulmonary arteries was usually atrophic, while intimal fibrosis on the basis of thrombotic lesions was regularly present.