Method dependent limits in a study on the natural history of coronary and cerebral atherosclerosis.

Important discrepancies were revealed in a study on human coronary and cerebral atherosclerosis among data furnished by gross inspection and by light microscopy. The character of atherosclerotic lesions, the meaning of the terms "normal intimas" "fatty streaks", "fibrous plaques" and "complicated lesions", the type of the early atherosclerotic lesions, the age period of the onset of these early lesions, their sequence of development, their relationship to advanced lesions--all appeared method dependent. The gross inspection alone led not only to an oversimplified, but also to a distorded view on the natural history of atherosclerosis, since it overlooked the role of intimal necrosis, incorporated microthrombi, fibromuscular plaques, mucoid plaques and foam cell-rich plaques in atherogenesis. The degree and extent to which the early stages of atherosclerotic involvement remained undetected by gross inspection was surprisingly great. The difference between the number of atherosclerotic plaques recorded on microscopic and macroscopic examination of the same vascular segments was statistically significant (p less than 0.01). Our results suggest that all basic studies of human atherosclerosis must include intermingled macroscopic and microscopic examination of the same arterial segments and require the use of an adequate terminology.