What Is Atherosclerosis?
Atherosclerosis (often spelled athersclerosis) 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.
Atherosclerosis plaque itself consists of fatty substances, 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 (atherosclerosis).
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 buildup 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, fatty substances (such as LDL and vLDL cholesterol) and minerals (such as calcium and other metals) 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 and repair effectively. If the arteries narrow, such 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.
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 in the arteries is the presence of a substance called "C-reactive protein" (CRP) in the blood. Levels of this marker (C-reactive protein) 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 buildup 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:
- 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
- Cramping pains in the calves (intermittent claudication)
- Pain in the hips and thighs (may be present depending on which arteries are blocked)
Click here for atherosclerosis risk factors and wellness tips.
What laboratory tests assess heart attack risk?
Heart attack risk can be assessed by measuring a wide range of markers,
including: CRP (c-reactive protein), homocysteine, transferrin, total cholesterol, HDL and LDL, fibrinogen (a globulin that affects blood coagulation), and apolipoproteinB (apoB) and apolipoproteinA-1 (apoA-1) levels, as well as apo ratios - the higher ApoB/APO A-1 ratio may signal an increased risk of cardiovascular disease. (apoB carries LDL and VLDL cholesterol) (apoA-1 carries HDL cholesterol)
One comprehensive test that can assess all these important heart health predictors from just one blood sample is called the Comprehensive Cardiovascular Report (CCR), and it's available from Great Smokies Diagnostic Laboratories.
Talk to your doctor about requesting the CCR test, or a similar type of test, to get an overall picture of your heart health risk, because simply writing a prescription for statins to address individual symptoms is a tunnel-vision treatment.
- Scientific opposition to the cholesterol hypothesis
- Statin Drugs - A Critical Review of the Risk vs Benefit Research
*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.