How do cholesterol and fatty plaques slowly narrow your arteries?
The artery disease behind the most common kind of heart attack usually starts in childhood and stays silent for decades, until a plaque suddenly breaks.
▶ Start the storyAtherosclerosis is a slow build-up of fatty deposits, called , in the walls of arteries. It is a chronic disease, driven by elevated blood levels of cholesterol, primarily , and it narrows arteries over many years. This lesson describes how it works; it is not medical advice.
Cholesterol travels around the body inside particles. , low-density lipoprotein, is one of the main kinds of particle that transport fat molecules through the fluid outside cells. LDL particles deliver cholesterol into the wall of an artery, and it is elevated blood levels of LDL that drive the disease. In the wall the cholesterol is released and oxidised, which attracts immune cells called . They swallow the oxidised fat and swell into foam cells, and when those die they keep the inflammation going. Under the microscope the early lesion looks like a fatty streak.
Over time the lesion becomes a plaque made of fat, cholesterol, immune cells, calcium and other substances from the blood. A protective fibrous cap forms over the fatty centre. The plaque narrows the artery and limits the flow of oxygen-rich blood to the tissue it feeds. The strange thing is how quiet this is: atherosclerosis is typically symptom-free for decades, because arteries enlarge at plaque locations and blood flow is not at first affected. Early processes likely begin in childhood, and almost everyone is affected to some degree by 65.
The dangerous moment comes when the thin covering of a plaque ruptures. That exposes its fatty centre to the blood, a clot forms and can block the artery, and if it happens in an artery feeding the heart muscle the result can be a heart attack. Plaque rupture is in fact the most common cause of heart attacks. In 2004 US data, a heart attack or sudden cardiac death was the first symptom in about 66 percent of men and 47 percent of women.
66% / 47%
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Recap
LDL carries cholesterol into the artery wall, immune cells swallow it, and the resulting inflamed plaque narrows the artery or ruptures.
💡 A trick to remember it · Think of grease in a drain: it builds up quietly layer by layer, and the real danger comes when a lump suddenly breaks loose and jams the pipe.
Surprising fact · It likely begins in childhood, and almost everyone is affected to some degree by age 65.
Sources (4)
No source, no claim. Every fact in this lesson (18 claims) cites at least one of these.