[Histological and ultrastructural changes in the liver in experimental pulmonary trunk stenosis at the stage of decompensation].

Pulmonary trunk stenosis was modeled in 25 dog puppies. Structural changes of liver were examined in 8 animals with circulatory decompensation and in 10 control dogs. Material was studied using histological, morphometric, stereometric and electron microscopical methods. Results showed that in decompensated pulmonary trunk stenosis with the hypoxia, the relaxation of the walls of both afferent and efferent hepatic vessels took place, the numbers and the degree of development of arterial adaptational structures (intimal musculature, muscular-elastic sphincters, and polypoid cushions) was reduced, while muscular bolsters in large and medium-sized vessels belonging to hepatic veins system, became atrophic. The adaptational mechanisms failure resulted in the development of chronic hepatic venous plethora.