This is a disease of the arterial wall in which the layer thickens, causing narrowing of the channel and thus, impairing blood flow.

It can occur in any area of the body, but is most important when it happens in the heart, brain or blood vessels leading to the brain.

The narrowing is due to the formation of plaques (raised patches) in the inner lining of the arteries. These plaques consist of low-density lipoproteins, decaying muscle cells, fibrous tissue, clumps of blood platelets, cholesterol,...