A histopathological study on the alteration on the pulmonary arterioles in the acquired valvular heart diseases (author's transl)

Abstract

The vasculature in the pulmonary circulation is known to have specific anatomic architecture and in this view point that alteration of the arterioles in pulmonary circulation attracts much attention of the physiologists, thoracic surgeons and pulmonary pathologists. Extensive pathological surveys of the hypertensive pulmonary vasculature have been hitherto reported, however, the vigorous studies of the pulmonary arterioles in acquired heart diseases should await further clarification. In this connection, the author has investigated the changes of the pulmonary arterioles in acqu'red heart diseases by the light microscope and electron microscope as well. The specimens were available either autopsy or surgical biopsy.For clarification of the alteration of the connective tissue involving the collagen fibrils and elastic fibers, the periodic acid methenarnine silver (PAM) stain and tannic acid stain (Mizuhira et al.) have been applied. The studied cases are as follows: Forty-three cases of autopsy; Aortic valvular disease (AVD) 15 cases, Mitral valvular disease (MVD) 20 cases, Combined valvular disease (CVD) 8 cases. Ten cases of surgical biopsy ; AVD 3 cases, MVD 3 cases, CVD 4 cases.Based on the criteria of Heath & Edwards, the relatively slight cases reveal swelling of the endothelial cells, medial fibrosis and edema, however, in cases which involved moderate or advanced pathological changes reveal intensive proliferation of PAM positive collagen fibrils of irregular configuration and increase of elastic fibers in media and adventitia. The latter is selectively demonstrated with tannic acid stain. The changes are frequently observed in rather in the mitral valvular disease than the aortic valvular disease. More detailed investigation reveals the sclerotic changes particularly involving the media and adventitia. These changes are also observed in cases of Grade 1 (Heath & Edwards) not only the severe cases which may be classified as Grade 3. The initial sclerotic changes involving the arterioles. eventually give the persisting derangement of the circulatory disturbance and finally may cause the sclerotic changes of the arteries at higher level.