A comparison of the role of the bronchial arteries in bronchiectasis and in experimental ligation of the pulmonary artery.

The hypertrophy of the bronchial arteries in bronchiectasis has been known to surgeons ever since resection of the lung had been practised for this condition. Histologists have noticed and commented upon the extreme vascularity of the tissue round the bronchiectatic sacs, and have tried to explain this as part of the general inflammatory change. The physiological importance and significance of this bronchial artery hypertrophy have only recently been appreciated. By means of perfusion experiments, followed by the preparation of complete vascular casts in neoprene, it has been possible to demonstrate accurately the anatomical extent of this hypertrophy, and to show that an extensive anastomosis develops between the bronchial arteries and the pulmonary arteries in these lungs. Moreover, the vascular pathology is comparable to that which occurs in the experimental dog after ligation of the pulmonary artery. This is a surprising observation, as the stimulus to the development of the bronchial collateral circulation appears to be so dissimilar in the two cases.