Pathomorphometrical characteristics of atherosclerosis in youth. A multinational investigation of WHO/World Heart Federation (1986-1996), using atherometric system.

Background And Aim: From 1986 to 1996, 1339 autopsies were performed on children and young adults, aged 5-34 years, in 18 countries of five continents in the course of the multinational investigation of the World Health Organization/International Society and Federation Cardiology (WHO/ISFC), "Pathobiological Determinants of Atherosclerosis in Youth" (PBDAY). A set of 966 left-half thoracic and 947 left-half abdominal aortae and 958 right coronary arteries were processed in the Center of Investigations and References of Atherosclerosis of Havana (CIRAH), i.e., one of the Reference Centers of the PBDAY. Pathomorphological and morphometrical analyses were carried out by a well-established method, the Atherometric System (AS).

Methods And Results: By qualitative analysis AS permitted the identification of each type of atherosclerotic lesions (AL). The quantitative analysis, using a digitizer (MYPAC-Japan, a PC-Pentium 200 Mhz-32 MB RAM), and the software Atherosoft, allowed the measurement of the intima surface occupied by any kind of AL, and estimation of the volume occupied and thus the degree of obstruction and stenosis of the lumen. The autopsy data were divided into three age groups: a) 5 to 14 years; b) 15 to 24 years and c) 25 to 34 and processed by age and sex. The commercial package NCSS was utilized for statistical analysis of the data.

Conclusions: Of particular interest were the following findings: a) Atherosclerosis increases with age; b) Fatty streaks (FS) were always present already at 5 years of age, independent of the country, climate, state of nourishment, type and amount of foods and the habits and lifestyle of the population studied. FS progressed most rapidly from 15 to 24 years. The fibrous plaque began to appear slowly at the end of the second and rapidly progressed after the third decades. The severe plaque was rarely observed before 30 years of age; it appeared in the fourth decade and then progressed slowly, but steadily.