Fibrin thrombosis in monocrotaline pyrrole-induced cor pulmonale in rats.

Investigations were carried out to determine the lung lesions responsible for the development of pulmonary heart disease, cor pulmonale, in rats treated with monocrotaline pyrrole or monocrotaline. Animals with right ventricular hypertrophy showed microscopic lung alterations consisting of alveolar edema; fibrin thrombi with partial to complete occlusion of arteries, arterioles, capillaries, and veins; connective tissue proliferation of alveolar septae; cellular hyperplasia of septae; and medial hypertrophy of arterioles. Due to the high incidence of fibrin thrombi in animals with right ventricular hypertrophy, we believe that formation of fibrin thrombi plays a decisive role in the development of chemically induced cor pulmonale.