Experimental pulmonary embolism by platelet agglutinates in dogs.

It is probable that small fibrin thrombi are constantly being formed in the venous system and become impacted in the lungs. The lungs of dogs are able to lyse several hundred millilitres of fresh blood clot injected into the venous system over a period of months and the animals' pulmonary arterial pressure remains normal (Marshall and Allison, 1962). Small emboli may, however, be composed of the formed elements of the blood such as platelets and leucocytes, and these emboli may be less susceptible to lysis and more able to produce a cumulative effect resulting in pulmonary hypertension. The present study was made to investigate the immediate physiological effect and the ultimate pathological effect of repeated pulmonary embolism by platelet agglutinates in dogs.