[Massive pulmonary embolism in dogs without pulmonary hypertension (author's transl)]

Copolymer granules (diameter 35-300 micron) were injected i.v. in 10 dogs to produce pulmonary hypertension. Not in a single dog, however, pulmonary pressure arose permanently, though up to 15 g of granules had been embolized over several months. Histological examination of the lung revealed that the granules are situated mainly outside the arteries. Necrotizing arteritis destroys the vessel wall and allows the emboli to leve the lumen. Abundant granulation tissue prevents severe hemorrhage. The inflammatory process decreases after months, leaving the vessel wall patent and free of emboli.