HYPOPERFUSION AND HYPERPERFUSION IN THE IMMATURE LUNG - PULMONARY ARTERIAL DEVELOPMENT FOLLOWING LIGATION OF THE LEFT PULMONARY-ARTERY IN THE NEWBORN PIG

  • 1 January 1981
    • journal article
    • research article
    • Vol. 82  (2) , 281-292
Abstract
The left pulmonary artery and ductus arteriosus were ligated in 14 newborn pigs. Animals were put to death at intervals of 2-24 wk of age. In each animal a cardiac catheterization study was performed before sacrifice. Pulmonary arterial development in both lungs was studied by applying quantitative morphometric techniques to the injected an inflated specimens. In the right lung, pulmonary arterial pressure and resistance fell to normal after birth; structurally, muscularity remained high in arteries < 75 .mu.m in diameter. Size and number of intra-acinar arteries increased normally, not excessively, with age depsite the abnormally high flow. After 16 wk in all animals, muscularity incrased significantly in arteries of all sizes; mean pulmonary aterial pressure was 20-35 mm Hg, the pulmonary-systemic pressure ratio was 0.21 or more and total pulmonary vascular resistance was 0.16-0.4 torr/(ml/min per kg) (normal, 0.08). In the left lung, the axial pulmonary artery and its branches were small, decreasing in size with age and its elastic wall structure was disorganized. Small preacinar arteries showed obliterative change in the majority of animals put to death at 16 wk or more. Within the acinus the bronchial arterial blood supply ensured almost normal postnatal pulmonary arterial development, the vessels increasing in size and number although muscularity was reduced. Failure to perfuse 1 pulmonary artery in the immature animal changes growth and development of both lungs, and the findings are discussed in relation to the hyperperfused and hypoperfused lung in childhood.