What is atherosclerosis?

Atherosclerosis is a disease process in which plaque (a mixture of cholesterol, calcium, and blood-clotting materials) builds up on the inner walls of the arteries. Atherosclerosis narrows arteries and causes them to harden, thicken, and become less elastic.
Narrowing of the carotid arteries is most commonly related to atherosclerosis (a build-up of plaque, which is a deposit of fatty substances, cholesterol, cellular waste products, calcium, and fibrin in the inner lining of an artery). Atherosclerosis, or "hardening of the arteries," is a vascular disease (disease of the arteries and veins).

It is unknown exactly how atherosclerosis begins or what causes it. Atherosclerosis is a slow, progressive, vascular disease that may start as early as childhood. However, the disease has the potential to progress rapidly. It is generally characterized by the accumulation of fatty deposits along the innermost layer of the arteries. If the disease process progresses, plaque formation may take place.

This thickening narrows the arteries and can decrease blood flow or completely block the flow of blood to the brain.
Atherosclerosis is a buildup of plaques (fat, cholesterol and other substances) in arteries that, over time, can narrow them and block blood flow.
The inner surfaces of the healthy arteries are smooth and flexible, and permit blood to flow freely and reach the muscle of the heart. When walls become clogged with scar tissue that includes fatty materials, the result is a condition known as atherosclerosis.

Many factors can contribute to atherosclerosis, some of which are: high blood pressure, elevated blood cholesterol, smoking, diabetes, a family history of atherosclerosis, and lack of regular physical activity. In some cases the reduced flow of blood to the heart can cause angina (chest pain, arm or throat discomfort), shortness of breath, or a heart attack. When blockage is severe, bypass surgery may be required to reroute the blood supply around a damaged or blocked coronary artery, a process known as "bypass grafting."
Anthony L. Komaroff, MD
Internal Medicine
The coronary arteries supply the heart's cells Two main arteries, the right coronary artery and the left coronary artery, deliver the entire supply of blood and oxygen. Like the branches of a tree, each main artery divides into progressively smaller channels that carry blood to the heart muscle cells. Any these arteries, large or small, can be narrowed by a buildup of fatty plaque. This buildup is known medically as atherosclerosis. This term combines two Greek words, athere (porridge) and sclerosis (hardening). The name is accurate: in atherosclerosis, the artery walls become filled with soft, mushy deposits that eventually make the artery hard, stiff, and narrow.
Mark B. Lampert, MD
Cardiology (Cardiovascular Disease)
Atherosclerosis is the process of cholesterol plaque building up in the arteries. Learn more from Dr. Mark Lampert on behalf of NorthShore University HealthSystem about Atherosclerosis.

Eric Olsen
Atherosclerosis is a buildup of fatty deposits inside the coronary arteries that will eventually restrict the flow of blood to the heart muscle. The buildup occurs slowly and probably begins in childhood, and it can take decades for the buildup to become severe enough to cause clinically manifest symptoms. But well before these deposits begin to affect our physical health, we're likely to experience a sense of disquiet, a subtle sense of early fatigability, a loss of zest for life, perhaps even low-grade depression.
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When plaque begins to accumulate in the arteries, the condition is called atherosclerosis. Plaque is caused by high cholesterol.  Your arteries are responsible for delivering oxygen to the various areas of the body. If these blood vessels become blocked, major health complications can develop like strokes or heart attacks
Dr. Mehmet Oz, MD
Cardiology (Cardiovascular Disease)
Atherosclerosis is a medical condition in which a fatty substance called plaque builds up on the inside walls of blood vessels, which can slow or eventually block the flow of blood. When this occurs in the coronary arteries, it is termed coronary artery disease, or CAD. To learn more about atherosclerosis and CAD, watch this animation.

Jack E. Dawson Jr., MD
Cardiology (Cardiovascular Disease)
Atherosclerosis is a technical term for plaque formation in the artery that can interfere with blood flow and cause damage in the organ supplied. After one or more risk factors causes damage to the wall of the inner lining of the artery, the repair process begins. This process is inflammation. The process becomes overwhelmed by constant exposures to the offending elements that produce damage. For instance, a high fatty meal, high blood pressure, cigarette smoking and high blood pressure are each damaging by themselves; but since they can all occur at one time, the repair system is unable to switch off and continues the inflammation intended to repair. This beneficial process, gone awry, then aggravates the plaque buildup process until switched off by significant lifestyle changes and medications, such as statins. If the process is not slowed or stopped, it progresses. The resulting plaque produced eventually constricts the blood flow to the heart muscle and results in muscle damage, a heart attack. Damage in other organ systems can also result if plaque restrictions are allowed to starve those organs from the life-giving blood and cause a stroke, kidney damage or problems with circulation to the legs.

Coronary Artery Disease, Coronary Heart Disease, Ischemic Heart Disease and Arteriosclerotic Cardiovascular Disease are different names for the same disease. The disease is caused by atherosclerosis, a buildup of fatty deposits in the coronary arteries.

Coronary arteries supply blood to the heart. When a blockage occurs in a coronary artery, blood flow to the heart muscle is decreased. The decrease becomes most evident during exertion, when the heart muscle works harder and needs more oxygen-enriched blood. By preventing the much needed increase in blood flow, a blockage deprives the heart of oxygen, thereby causing the heart muscle to hurt. Chest pain from this scenario is called angina or Angina Pectoris. If cell death occurs, then it is called an infarction. A heart attack is cell death of heart muscle (myocardium) therefore a heart attack is called a Myocardial Infarction.

The condition that causes Coronary Artery Disease, angina and heart attacks is called atherosclerosis, a more general term for the hardening of the arteries. Atherosclerosis is one type of arteriosclerosis that can cause a buildup of fatty material (atheromas and plaques) along the inner lining of arteries.

The blockages can cause a number of different outcomes, depending on where they occur:

  • When the blockage occurs in a coronary artery, it can cause chest pain (angina).
  • When the blockage is complete, it may cause a heart attack (Myocardial Infarction or MI).
  • When the blockage occurs in one of the arteries close to the brain, a stroke can occur.
  • When the blockage occurs in a leg artery, it can cause Peripheral Vascular Disease and can cause pain while walking called intermittent claudication.

Hardening of the arteries takes many years to develop - decades really - and the condition can easily go unnoticed. Symptoms, such as angina, can indicate the condition gradually. However, it also can go unnoticed until it becomes evident in a sudden and severe way - such as a heart attack.

Robert S. Kaufmann, MD
Internal Medicine
Atherosclerosis is a disease in which plaque builds up on the insides of your arteries. Arteries are blood vessels that carry oxygen-rich blood to your heart and other parts of your body.

Plaque is made up of fat, cholesterol, calcium, and other substances found in the blood. Over time, plaque hardens and narrows your arteries. The flow of oxygen-rich blood to your organs and other parts of your body is reduced. This can lead to serious problems, including heart attack, stroke, or even death.

This answer from the National Heart, Lung, and Blood Institute has been reviewed and/or edited by Dr. Robert S. Kaufmann.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.