Morphological changes of the heart arteries in experimental stenosis of the pulmonary artery trunk and their reversibility after correction of the defect.

Experimental stenosis of the pulmonary artery trunk was induced in 48 puppies, and using a comprehensive histomicrometric method the condition of the heart arteries was investigated during the defect and after its correction. Six to twelve months after the operation, the young dogs developed cardiac hypertrophy, hyperplasia of the minute branches of the coronary arteries and hypertrophic-hyperplastic changes in the wall of the coronary arteries at all levels of their branching. In 18 puppies, the stenosis was corrected, which after 6 to 12 months led to a regression of the hypertrophic changes in the heart and its vessels. At the same time, the arterial bed got gradually adapted to the new conditions of circulation, which was manifested by the fact that part of the minute arteries changed into closing-type arteries, and blood flow in them decreased.