[A new experimental model of pulmonary hypertension in dog using an adjustable pulmonary artery band]

In order to study pathogenesis, reversibility, and treatment of pulmonary hypertension in congenital heart disease, a new experimental model to induce pulmonary vascular diseases has been designed. Previous models by other investigators were anastomosis between a systemic artery and pulmonary artery of one lung lobe, and these could not provide constant induction of pulmonary vascular diseases. Furthermore the postoperative mortalities in their experiences were quite high and acute iatrogenic pathological changes such as bleeding, edema and emphysema developed in the pulmonary vasculature and parenchyma of the anastomosed lobe. Use of our adjustable pulmonary artery band has eliminated such unwanted complications. The surgical procedure includes an end-to-side anastomosis of the left main pulmonary artery to the descending thoracic aorta, and banding of the anastomosed pulmonary artery using the adjustable band. The band was gradually loosened by extrathoracic manipulation during three to four weeks observation after operation. This technique provided dogs to survive sufficiently long enough and with a high success rate, and to produce extremely advanced pulmonary vascular diseases. Of the twenty dogs operated such, eighteen survived the first postsurgical week and thirteen dogs developed hypertensive pulmonary vascular diseases. Development of the medial hypertrophy was evident at one week and gradually advanced. In eight weeks, intimal cellular proliferation (Grade 2 of the Heath & Edwards' classification) became apparent. In twelve weeks, the intimal proliferation became fibrous and acellular (Grade 3) and caused complete obstruction of the lumen of some muscular arteries. In twenty weeks specimen, typical plexiform lesions (Grade 4) and dilatation lesions (Grade 5) involved the small muscular arteries in the whole left lung.(ABSTRACT TRUNCATED AT 250 WORDS)