Study of fibrous plaques occurring in the coronary arteries of children.

The pathology of the coronary arteries of children, in relation to atherosclerotic involvement, appeared as a pathology of the main emergence areas and branching points of the left coronary artery and particularly of the anterior descending artery. The first atherosclerotic lesions occurred as non-raised fibrous plaques in 2% of children 6--10 years old and in 4% of children and juveniles 11--15 years old. In the latter age group fatty streaks and gelatinous plaques were also seen in 6% of the subjects; in their appearance they lag behind fibrous plaques by 5--8 years. Indirect evidence was obtained that some branch pads or cushions might be converted into fibrous plaques. The transitional aspects included edema, histolysis (elastolysis, collagenolysis, ground-substance depletion and degenerative cell changes), followed by reorganization and homogeneization of the pre-existing heterogeneous microarchitecture; in a final stage the prevalent processes seemed to be the nodular proliferation of smooth muscle cells and the abundant neoformation of collagen fibers. In essence the results show that in atherosclerosis the coronary arteries are involved in a different sequence and histogenetic pattern than the aorta.