Necrotizing pulmonary arteriopathy associated with pulmonary hypertension.

The occurrence of pulmonary arteriosclerosis and arteriolosclerosis has long been recognized. Such structural changes in the pulmonary vasculature have usually been considered to represent an adaptation to alterations in the haemodynamics of the lesser circulation. In particular, their presence has been related to pulmonary hypertension, and they have been compared to the changes which occur in the systemic vasculature in association with hypertension of the major circulation. It is interesting that there does not appear to be a pulmonary arteriolar counterpart of the hyaline sclerosis of the smaller systemic arterioles which is so characteristic of " essential " systemic hypertension; the explanation of the nonoccurrence of this type of hypertensive arteriolar change in the pulmonary vasculature is probably to be found in the structural differences which exist between pulmonary and systemic arterioles. There are remarkably few published observations concerning the association of pulmonary hypertension with necrotizing pulmonary arteriolar lesions which might be considered to be analogous to the necrosis of systemic arterioles seen in cases of malignant systemic hypertension. Parker and Weiss (1936) studied the lungs in a series of cases of mitral stenosis. In five of these cases in which there was clinical and morbid anatomical evidence of severe embarrassment of the pulmonary circulation they observed necrotizing pulmonary arteriolitis in addition to hyperplastic arteriolosclerosis. They stressed the similarity between these structural changes in the pulmonary arterioles and those which are found in renal arterioles in cases of malignant systemic hypertension. Desclin and Gepts described a similar case in which mitral stenosis was associated with arteriolosclerosis and arteriolitis affecting only the pulmonary vessels; they likened the arteriolitis to polyarteritis nodosa, and suggested that the various vascular changes corresponded to the conditions grouped by Rossle (1933) as the rheumatoid affections of blood vessels. Only two cases have been reported in which a congenital cardiovascular malformation was associated with a necrotizing arteriopathy limited to the pulmonary arterial tree. In both instances the patient was a boy, aged 11 years, who had been known since birth to have a cardiac lesion which caused exertional dyspnoea and