Bronchiolar Morphology After Systemic Arterial Interruption

Abstract

To assess ischemic lesions as a fac tor in obliterative bronchiolitis after lung transplantation, the authors sev ered the left bronchial arteries of 15 dogs, together with the left stem bronchus, the latter being immedi ately reanostomosed. They examined the bronchioles at weekly intervals up to three and a half months. On the week chosen each dog was anesthe tized, totally heparinized, and exsan guino-perfused with saline. Just after heart arrest, the thoracic aorta was injected with a barium solution until this white medium appeared in the bronchial arteries. The heart-lung blocs were excised en bloc, submitted to soft-tissue x ray, fixed, and then sliced to 1 cm. Corresponding right and left 5-mm-thick samples of these slices were prepared for contact mi croradiography followed by histo logic 5-to-20-micron-thick, stained, correlated specimens. For two weeks the left bronchial arteries remained empty, but there was no necrosis or edema. Between two and four weeks barium solution appeared in the bronchial arteries, and the bronchio lar epithelium had become multi stratified. Later the left bronchian giogram became similar to the right, but there were more folds of the mu cosa and a little submucosal fibrosis. These studies provide proof that no significant ischemic lesions occurred during repermeation of the bronchio lar vascular bed. Ischemia, if exist ent, is not a significant factor in obliterative bronchiolitis.