Structural rebuilding of pulmonary vessels at various haemodynamic shifts in the lesser circulation.

The rebuilding of pulmonary vessels at hypo- and hypertension in the lesser circulation was studied in 41 puppy dogs, in which hypotension had been induced by stenosing the pulmonary artery. Eighteen animals were successively sacrificed 6--9 months after the surgery. Histological examinations revealed atrophic and sclerotic lesions of the pulmonary arteries. In the remaining 23 animals, various anastomoses were formed between the systemic and pulmonary circulation systems, which led to the formation of hypertrophic and hyperplastic alterations in the pulmonary vessels and to pulmonary hypertension.