Intimal thickening in the coronary arteries of infants and children as an indicator of risk factors for coronary heart disease.

Narrowings of the coronary arteries were measured in 94 infants aged less than 1 year who died in hospital and 102 1- to 16-year-old children who died accidentally. The arteries were transformed mathematically to circles. The degree of narrowing caused by intimal thickening was determined as the ratio of intimal area to the original luminal area. This ratio was further transformed to percentage. The degree of narrowing varied between 0 and 58% (mean 20%). The mean degree of narrowing in the left coronary artery during the first year of life was 17% and, between 12 and 15 years, 34%. Narrowing was greater in males (P = 0.02), when all the 333 coronary samples were included in the analysis. The birthplaces of the subjects' grandparents were traced from population registers and it was found that narrowing in the left coronary artery of infants was greater in those descended from grandparents from eastern Finland, an area of high mortality from coronary heart disease (CHD). Intimal thickening in infants and children seems to be a morphological manifestation of hereditary predisposition to CHD.