Pathological studies of the animals replaced totally with the artificial heart. Part I. Concerning lungs, natural heart, and brain.

Pathological studies using routine pathological technics, microangiography and electron microscopy were performed on the 28 goats with an artificial heart (including 2 goats which survived for 30 and 37 days). In this paper, the brain, natural heart, and lungs of the goats were discussed. No special findings were seen in the brain except for rare infarcted areas. The natural heart almost always showed infarction-like lesions in the sub-endocardium and myocardium at the cut surface. The longer the animal survive, these findings became the more serious. The light microscopic findings on the lungs were classified into 6 groups. The most important findings of them are massive, diffuse exsudation with hemorrhage and its changes to chronic status. The main pathophysiological status, causing the pulmonary lesions, seemed to be peripheral circulatory insufficiency with increased permeability of peripheral vessels, especially of venulae. Thrombi were detected more frequently in the kidneys and lungs than in any other organs. The vascular walls where the thrombi were attached to, where often seen to be damaged, so that almost all thrombi were thought to be formed in the local vessels in situ, but not in the artificial heart. The main clinical causes to the pulmonary insufficiency were thought to be surgical operation including anesthesia, functional incompleteness of the artificial heart, etc.