How does atherosclerosis develop?

Although the exact process is not completely understood, scientists have described three different stages of atherosclerosis that lead to clogged arteries. These stages do not necessarily occur in order, nor is there always a progression from one stage to the next.

The fatty streak

The first evidence of atherosclerosis can be found in children 10 to 14 years old. The "fatty streak" appears as a yellow streak running inside the walls of the major arteries, such as the aorta. The streak consists of cholesterol, white blood cells, and other cellular matter. The fatty streak by itself does not cause symptoms of heart disease but can develop into a more advanced form of atherosclerosis, called fibrous plaque.

The plaque

A plaque forms in the inner layer of the artery. The plaque consists of large numbers of cells that are filled with cholesterol. When a plaque grows in the artery, it may block blood flow, causing the symptoms of stable angina.

Complicated lesion

The last stage of atherosclerosis occurs when the plaque breaks open, exposing the cholesterol and tissue underneath. Blood clots form in response to this rupture and cause symptoms of a heart attack and unstable angina.