Atherosclerosis, Cardiovascular Disease

WHAT IS ATHEROSCLEROSIS?

Atherosclerosis is a disease of the arteries in which a fatty/wax-like substance (plaque) is deposited on the inside of the arterial walls. As this substance builds up, it causes the arteries to narrow. Over time, this narrowing prevents the blood from flowing properly through the arteries, giving rise to congestive heart failure, heart attack, or stroke.
Plaque itself consists of fatty substances, oxidized cholesterol, cellular waste products and calcium. If part of this plaque breaks away, it can travel in the bloodstream to a point where the artery is narrow enough for the plaque to completely block it. If the affected artery feeds the heart, a heart attack may result, and if it feeds the brain, a stroke may result.

Atherosclerosis also causes high blood pressure (hypertension). As the blood is forced through the narrowed arteries, it exerts more pressure on the walls. This also increases the risk of stroke and heart attack. Angina (chest pain) is another condition caused by narrowing of the arteries.

HOW DOES ATHEROSCLEROSIS PROGRESS?

Atherosclerosis is a slow, complex disease that starts in childhood. As a person ages, atherosclerosis is likely to worsen as more plaque is deposited in the arteries. In some people—even those in their 30s—atherosclerosis progresses quickly. While the exact cause of atherosclerosis remains unknown, many researchers believe that the build-up of plaque begins when the innermost layer (endothelium or intima) of the artery becomes damaged by free radical attack (oxidation) and associated inflammation. Either as the body’s attempt to repair this damage, or simply because they become trapped, oxidized fatty substances (such as LDL cholesterol) and minerals (such as calcium) collect at the site of the damage forming a plaque that narrows the affected artery opening.

Note: Arteries carry blood rich in oxygen and nutrients to the tissues of the body, providing the fuel needed by the cells to function properly. If the arteries narrow as is the case with atherosclerosis, less nutrients and oxygen will be delivered to the tissues associated with those narrowed arteries. Lowered nutrient and oxygen supply leads to progressive cell death and loss of tissue function.

HOW COMMON IS ATHEROSCLEROSIS?

Just how much of the population has atherosclerosis is hard to determine. However, approximately one in six North Americans have cardiovascular disease in some form or another, and most of these diseases begin with atherosclerosis.

ATHEROSCLEROSIS AND INFLAMMATION

Recently, many heart experts have been examining the role played by inflammation in the development of atherosclerosis (and therefore, more advanced stages of heart disease). Many now believe that there is a link between arterial damage, the inflammatory process and coronary atherosclerosis. One of the indications of inflammation is the presence of a substance called “C-reactive protein” (CRP) in the blood. Levels of this marker are elevated when heart disease is present because the plaque in diseased arteries typically contains inflammatory cells. In a survey of 388 British men aged 50-69, the prevalence of coronary artery disease increased 1.5 fold for each doubling of CRP levels*.

It follows that reduction of damage and inflammation within the arteries may inhibit plaque build-up and thereby reduce risk of atherosclerosis and associated heart conditions.

WHAT ARE ATHEROSCLEROSIS WARNING SIGNS?

The specific symptoms of atherosclerosis depend on what arteries are affected.

When arteries to the brain are affected, atherosclerosis warning signs include:

• Headaches
• Dizzy spells
• Ringing of ear
• Memory problems
• Poor concentration
• Mood changes

When arteries to the heart are affected, atherosclerosis warning signs include:

• Chest pain (angina)
• Elevated blood pressure

When arteries to the arms or legs are affected, atherosclerosis warning signs include:

• Aching muscles
• Fatigue
• Cramping pains in the calves (intermittent claudication).
• Pain in the hips and thighs (may be present depending on which arteries are blocked).

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*Mendall MA, Patel P., Ballam L., et al. C-reactive protein and its relation to cardiovascular risk factor: A population based cross sectional study. BMJ. 1996;312:1061-1065.