Coronary arteries in fetuses, infants, and juveniles.

The coronary arteries of young individuals ranging from fetuses to young adults were studied. Sclerotic lesions were not demonstrated in the coronary arteries of fetuses. In infants the early stages of arteriosclerosis were frequently present and consisted of rupture, degeneration and re-generation of the internal elastic membrane, deposition of mucopolysaccharide, and proliferation of endothelial cells and fibroblasts. These alterations were most prominent in infants of 3 to 4 months. In older individuals there was an apparent decrease in the rate of intimal fibrosis. The lesions of the coronary arteries of young individuals were identical with the early phases of arterio-sclerosis in adults. IN A previous study of the coronary arteries it was observed that many different patho-logic processes participated in the development of arteriosclerosis and that these processes had an orderly sequence of evolution.' The earliest pathologic lesions were deposition of muco-polysaccharide in the intima, rupture and degeneration of elastic tissue, and proliferation of subendothelial fibroblasts; these were followed by regeneration of elastic tissue and formation of collagen fibers in plaques; the later stages were characterized by deposition of lipid and cholesterol, hyaline degeneration of fibrous connective tissue, calcification, intra-mural hemorrhage, and thrombosis. The purpose of the present study is to determine the nature and frequency of pathologic processes in the coronary arteries of young individuals. MATERIALS ANSD METHODS The hearts of 105 individuals were examined. The ages varied from fetuses of 31 2 months' gestation to young adults in their early twenties. The ages and sexes are shown in table 1. In all of the individuals death had occurred suddenly, without prior clinical evidence of illness, and usually from a violent physical injury. The proximal segments of the left anterior, left circumflex, and right coronary arteries were removed and fixed in formalin, and paraffin sections were prepared. The sections were stained with hematoxylin and cosin, Weigert's elastic-tissue stain, colloidal iron-prussian blue stain for acid mucopoly-saccharide,2 and a modification of the aldehy-de-fuchsin reaction3 for elastic tissue. In and the San Francisco Heart Association. 263 many cases, frozen sections of coronary arteries were stained with oil-red 0 and hematoxylin and contiguous sections were stained bya the procedures used for paraffin sections. RESULTS Fetuses. The coronary arteries of fetuses were the only ones in which no pathologic processes were observed (fig. 1A). The intima consisted of a single layer of endothelial cells lying directly on the internal elastic membrane. The internal elastic …