Pathology of the pulmonary vascular tree. IV. Structural changes in the pulmonary vessels in chronic left ventricular failure.

Previous studies in this series demonstrated structural changes in the pulmonary vascular bed as the result of mitral valvular disease and other cardiac disorders. The present study demonstrates changes in the lungs as the result of chronic left ventricular failure; these changes were like those produced by mitral stenosis. The most pronounced disturbance was medial hypertrophy. The exact mechanism is not known, but it probably is related to increased pulmonary venous pressure. We TITH the increased knowledge of cardiovascular physiology imparted by means of cardiac catheterization, parallel interest has been manifested in the structural changes that occur in the pulmonary vascular tree under various conditions, especially those associated with increased pulmonary arterial pressure. In earlier studies it has been demonstrated that in mitral stenosis' 2 and in mitral insufficiency,3 as well as in other cardiac disorders, structural changes may occur in the pulmonary vascular bed.4 When cardiac disease creates an impediment to pulmonary venous outflow, the pulmonary vascular changes are primarily those of medial hyper-trophy of the muscular arteries. Chronic left ventricular failure, like mitral stenosis or mitral insufficiency, is associated with impaired pulmonary venous outflow and increased pulmonary "capillary" and arterial pressures.5-9 The thought that this functional 801 derangement might be associated with de-monstrable structural changes in the pulmonary vascular tree led to the present study on histologic changes in the pulmonary vessels in cases of chronic left ventricular failure. MATERIAL AND METHODS Initially, it was desired to have three groups as follows: Group 1 included cases in which chronic left ventricular failure had resulted from calcific aortic stenosis or systemic hypertension. Group 2 included cases of calcific aortic stenosis or systemic hypertension without left ventricular failure. Group 3 included cases in which cardiovascular disease was absent. Later, a fourth group was studied; this group was made up of cases in which mitral stenosis was present. Emphysema10 and other forms of pulmonary disease and aging may be associated with structural abnormalities in the pulmonary vascular tree. In order to exclude such cases as far as possible, records of patients 60 years of age or more were not included. Selection of cases for study included histo-logic examination of pulmonary tissue from persons potentially to be included in one group or another without knowledge at the time of this examination into which group the case would be placed if em-physema and other pulmonary diseases were not present. If pulmonary disease was …