[The anatomicofunctional picture of the atherosclerotic lesion].

The natural history of atherosclerotic disease is characterized by a first asymptomatic phase, when the lesion develops and a second one, the more dramatic symptomatic phase, when the mature plaques, which represent the progression of the early lesions, and their complications produce a wide range of clinical phenomena. After 1 year of age all children show changes in coronary arterial wall, consisting of cell proliferations, which may be considered as precursors of atherosclerosis. These cells migrate from the tunica media of the coronary artery, proliferate, may synthetize connective tissue and lose the ability to degrade plasma lipoproteins. As a consequence, they may be laden of cholesterol, which accounts for fatty streaks. Later on, near 25% of 15-20 year old children are found to be affected by silent non-obstructive coronary atherosclerotic plaques, which consist of raised lesions, the fibrous plaque, made up of frequently lipid laden cells and fibrous tissue. The lesion-prone area is chiefly the proximal anterior descending coronary artery at the site where the worst precursors of atherosclerosis are usually detected. The medial coat of the vessel retain at this stage a good thickness, which accounts for the vasoreactivity of the coronary artery in youths and young-adults. The trigger in the cascade of dynamic events which lead to the advanced lesions remains a mystery. The plaque is not a static immutable structure, but is subjected to growth with consequent stenosis of the lumen and continuing modification and remodelling which involve all the 3 coats of the arterial wall