The Change of the Vessel Markings by Ligation of the Branch of the Pulmonary Artery

In relation with the collapse therapy of the lung, I observed the change of vessel markings of the lobe when the secondary atrophy of the lung occurs by ligation of pulmonary artery. Using a cat weighing 2-3 kg, I obtained specimens by infusing dyes in a living cat at various periods after operation. The results were as follows. 1) There were observed no dangerous symptoms by the ligation of the branch of the pulmonary artery. The necrosis of the ligated lobe did not occur. 2) Directly after the ligation there occurs a formation of a collateral pathway by a capillary communication from the vessels of the bronchial wall which extends to the wall of the alveolus, then by the newly built vessels which came outside the lobe through the adhesion with the peripheral area of it. 3) By ligation a thrombus will be formed in the pulmonary artery but a circulating pathway can be noticed inside the thrombus. This is considered to be a circulating pathway retrogradely to the pulmonary artery through the capillary net work of the alveolus wall by the vessels of the bronchial walls and the vessels which invaded from the outside of the lobe through the adhering portion. A week after the ligation the thrombus is nearly absorbed and the recovery of the circulation inside the pulmonary artery can be noticed. 4) The change of the lobe which occurs by the ligation of the branch of the pulmonary artery can be applied clinically