PURPOSE--To analyze macro and microscopic features of atherosclerotic plaques located in bifurcation of coronary arteries, defining their spatial disposition in those sites. METHODS--We studied 38 bifurcations of coronary arteries of patients whose cause of death was related to coronary artery disease. Histologic sections of 0.5mm were sequentially made from the main artery to the secondary branches. They were stained with hematoxilin-eosin technique.

Histological analysis evaluated:

a) morphologic composition of the plaques, b) degree of obstruction and c) plaque's disposition. RESULTS--a) Plaque's composition: fibrolipid plaques constituted 80 per cent of the cases and mingled focal atrophy of the media at the base of the plaque in 61 per cent with spots of total destruction and rupture of the elastic layers in 30 per cent ; b) degree of obstruction: ranged from 20 per cent to 95 per cent , with average 60 +/- 28 per cent ; c) disposition of plaques: we verified morphologic variation along the plaque, most of them (71 per cent ) being eccentric at bifurcation and not reaching the beginning of flow divider walls. CONCLUSION--Atherosclerotic plaques located in bifurcation of coronary arteries of adults are often fibrolipid plaques, eccentric, and their spatial disposition on those sites spare the beginning of the inner walls, reaching the outer walls