[Dilatation of the pulmonary artery in pulmonary stenosis].

Dilatation of the pulmonary artery occurs frequently in cases of valvular pulmonary stenosis and is often called "poststenotic." We determined the diameter of the pulmonary artery angiocardio-graphically and compared this with the data obtained by heart catheterization in cases of pulmonary stenosis and of idiopathic dilatation of the pulmonary artery. Features are presented which constitute arguments in favor of Laubry 's suggestion that we are dealing with two (different abnormalities , namely, a valvular stenosis and a dilatation of the pulmonary artery though hydraulic forces may contribute to the final development of the dilatation. D ILATATION of the pulmonary artery is observed in the majority of cases of pure valvular pulmonary stenosis. This dilatation is often called poststenotic, on the assumption that it results from the stenosis. It is thought that whirls are formed in the blood flow distal to the stenosis, which cause the dilatation. The investigation of Cavina,2 who succeeded in producing pulmonary stenosis in rabbits, is sometimes referred to in support of this hypothesis. In these experiments, a dilata-tion of the pulmonary artery was also repeatedly brought about. Histologic examination of the wall of the pulmonary artery, however, led Cavina to the conclusion that the dilatation was due to the disturbed nutrition of the pulmonary arterial wall, since the vasa vasorum were also occluded by the silk thread applied around the pulmonary artery to produce the stenosis. Cavina has emphatically pointed out that, in his opinion, the stenosis itself cannot be regarded as the causative factor. Halsted,6 who observed the development of "a mild dilata-tion distal to partial ligation of the terminal aorta." also stated that "it is not denied that the paralysis of the vasomotor nerves and the occlusion of the vasa vasoruin may possibly play some part in the manifestation". Recently, Holman7 has expressed the opinion that the dilatation of the pulmonary artery is the result of the stenosis; he based this opinion upon experiments using elastic rubber tubing. 719 We propose to report some clinical findings which, in our opinion, are difficult to reconcile with the conclusion of Holman and also of others. METHOD The diameter of the pulmonary artery was (le-termine(l in patients with various degrees of pure pulmonary stenosis. In order to judge the size of the pulmonary artery, as a rule the degree of prominence of the pulmonary arch in x-ray films or during screening in the frontal and oblique positions, …