What Is It?
Atherosclerosis is the build up of a waxy plaque on the inside of blood vessels. It affects only the inner lining of an artery and is characterized by plaque deposits that block the flow of blood, and is often called arteriosclerosis. Atherosclerosis, a progressive process responsible for most heart disease, is a type of arteriosclerosis or hardening of the arteries. Plaque is made of fatty substances, cholesterol, waste products from the cells, calcium, and fibrin, a stringy material that helps blood to clot. As the inner layer of the artery wall thickens, the artery's diameter is reduced, and blood flow and oxygen delivery are decreased (World of Health 2007). Plaques can rupture or crack open, causing the sudden formation of a blood clot (thrombosis). Atherosclerosis can cause a heart attack if it completely blocks the blood flow in the heart or coronary arteries. It can cause a stroke if it completely blocks the brain or carotid arteries. Atherosclerosis can also occur in the arteries of the neck, kidneys, thighs, and arms, causing kidney failure or gangrene that leads to amputation.
Description:
The arteries are blood vessels that carry blood from the heart to all parts of the body. Arteries are made up of several layers of tissue that are normally soft and pliable. The layers must be able to expand and contract as blood passes through them. Arteries often become leathery and rigid. When that happens, blood may flow less easily through the arteries. The hardening of arteries is called arteriosclerosis. Many factors can cause arteriosclerosis. Normal aging, high blood pressure, and certain diseases, such as diabetes, are common causes of arteriosclerosis. Atherosclerosis is a special form of arteriosclerosis. In atherosclerosis, only the inner lining of the artery is affected. Fatty materials deposit on the lining of the artery, forming a larger and larger mass. The mass is usually called a plaque. It becomes more and more difficult for blood to flow through the artery. Eventually the artery may close completely (2007). The formation of a plaque in an artery can lead to a number of cardiovascular problems. If the plaque forms in an artery that leads to the heart, it may block the flow of blood to the heart, and a heart attack may occur. If the plaque occurs in an artery that leads from the heart, it may prevent the brain from getting the blood and oxygen it needs. The result is a stroke. The plaque may also break off from the artery wall and travel through the bloodstream. It may then block an artery somewhere else in the body, a process known as thrombosis. A thrombosis that blocks an artery in the heart produces a condition known as a coronary thrombosis. Atherosclerosis can occur anywhere in the body. It can affect arteries of the neck, kidneys, thighs, and arms. In such cases, the interruption of blood flow can produce many medical conditions, such as kidney failure and gangrene (death of tissue).
Symptoms:
The symptoms of atherosclerosis vary somewhat depending on the location of a plaque. If the plaque occurs in the arteries of the heart, the patient may experience chest pain, heart attack, or sudden death. A plaque in the brain may lead to sudden dizziness, weakness, loss of speech, or blindness. In arteries of the leg, plaques can lead to cramping and fatigue in the legs when walking. A plaque in the kidneys can cause high blood pressure that is difficult to treat.
Description:
The arteries are blood vessels that carry blood from the heart to all parts of the body. Arteries are made up of several layers of tissue that are normally soft and pliable. The layers must be able to expand and contract as blood passes through them. Arteries often become leathery and rigid. When that happens, blood may flow less easily through the arteries. The hardening of arteries is called arteriosclerosis. Many factors can cause arteriosclerosis. Normal aging, high blood pressure, and certain diseases, such as diabetes, are common causes of arteriosclerosis. Atherosclerosis is a special form of arteriosclerosis. In atherosclerosis, only the inner lining of the artery is affected. Fatty materials deposit on the lining of the artery, forming a larger and larger mass. The mass is usually called a plaque. It becomes more and more difficult for blood to flow through the artery. Eventually the artery may close completely (2007). The formation of a plaque in an artery can lead to a number of cardiovascular problems. If the plaque forms in an artery that leads to the heart, it may block the flow of blood to the heart, and a heart attack may occur. If the plaque occurs in an artery that leads from the heart, it may prevent the brain from getting the blood and oxygen it needs. The result is a stroke. The plaque may also break off from the artery wall and travel through the bloodstream. It may then block an artery somewhere else in the body, a process known as thrombosis. A thrombosis that blocks an artery in the heart produces a condition known as a coronary thrombosis. Atherosclerosis can occur anywhere in the body. It can affect arteries of the neck, kidneys, thighs, and arms. In such cases, the interruption of blood flow can produce many medical conditions, such as kidney failure and gangrene (death of tissue).
Symptoms:
The symptoms of atherosclerosis vary somewhat depending on the location of a plaque. If the plaque occurs in the arteries of the heart, the patient may experience chest pain, heart attack, or sudden death. A plaque in the brain may lead to sudden dizziness, weakness, loss of speech, or blindness. In arteries of the leg, plaques can lead to cramping and fatigue in the legs when walking. A plaque in the kidneys can cause high blood pressure that is difficult to treat.
- In the coronary (heart) arteries: Chest pain, heart attack, or sudden death.
- In the carotid (brain) arteries: Sudden dizziness, weakness, loss of speech, or blindness.
- In the femoral (leg) arteries: Disease of the blood vessels in the outer parts of the body (peripheral vascular disease) causes cramping and fatigue in the calves when walking.
- In the renal (kidney) arteries: High blood pressure that is difficult to treat.
Beltina (n.d.)
What Causes It?
The exact cause of atherosclerosis is not known. Some researchers consider it to be a natural consequence of aging. But that theory does not explain the actual process of the disease. What is known is that people with certain risk factors are much more likely to develop atherosclerosis than people without those risk factors. Some risk factors are beyond a person's control. For example, some people seem to be genetically more inclined to develop atherosclerosis than other people. Also, the disorder is more common among older than younger people. A person is not able to do much about his or her heredity or the aging process (Gale 2007).
Some risk factors, however, are under a person's control. These factors include:
Some risk factors for atherosclerosis that cannot be changed include:
Some risk factors, however, are under a person's control. These factors include:
- Cigarette/tobacco smoking: Smoking increases the risk of developing atherosclerosis. It also increases the risk of dying from heart disease. Second-hand smoke may also increase risk.
- High blood cholesterol: Cholesterol is a soft, waxy substance produced naturally by the body. It also occurs in many foods, such as meat, eggs, and other animal products. A certain amount of cholesterol is needed to keep the body healthy. But high levels of cholesterol can increase the risk of atherosclerosis.
- High triglycerides: Triglycerides (pronounced tri-GLIS-uh-ride) are a form of fat. High levels of trigylcerides have been linked with various kinds of artery disease.
- High blood pressure: Blood pressure higher than normal (normal is 140 over 90) can make the heart work hard. Both the heart and arteries may become weak.
- Physical inactivity: Lack of exercise increases the risk of atherosclerosis.
- Obesity: Excess weight strains the heart. Both heart and arteries may be damaged.
- Diabetes mellitus: Many diabetics die from heart attacks caused by atherosclerosis.
Some risk factors for atherosclerosis that cannot be changed include:
- Heredity: People whose family members have had atherosclerosis are at risk for the disorder.
- Gender: Before age sixty men are more likely to have atherosclerosis than women. After sixty, the risk is equal for men and women.
- Age: The risk for atherosclerosis increases with age.
This image here depicts the progression of Atherosclerosis (The Gale Encyclopedia of Science 2010)
How Do We Fix It?
Mild cases of atherosclerosis can often be treated with changes in lifestyle. Patients can reduce the amount of fats and cholesterol in their diet, quit smoking, lose weight, and become more physically active. For more serious forms of atherosclerosis, other treatments may be necessary. These include the use of drugs and various forms of surgery. A class of drugs that is used with atherosclerosis are designed to lower cholesterol. If the amount of cholesterol in the blood is reduced, the chance that plaques will form is also reduced. Aspirin may also be recommended because it tends to cause blood to become thinner (2007). One form of surgery used with atherosclerosis is angioplasty. In angioplasty a catheter tipped with a balloon is inserted into a blood vessel in the patient's thigh or arm. The catheter is then pushed upwards into the artery where a plaque exists. At that point, the balloon is inflated. The balloon pushes on the plaque. It may squeeze the plaque enough to open the artery to its normal size. Blood is then able to again flow through the artery. Bypass surgery may also be used to treat atherosclerosis. In bypass surgery, the portion of an artery that is blocked by plaque is clamped off. A blood vessel is taken from some other part of the patient's body and inserted just before and just after the section of artery that has been blocked off (2007). Blood is given a new pathway to flow through the body, bypassing the damaged artery. Bypass surgery is completely successful in about 70 percent of all cases and partially successful in another 20 percent. The key to reducing the risk for atherosclerosis is to reduce the risk factors over which an individual has control, which includes:
A protein called apolipoprotein E, which can exist in several different forms, is coded for by a gene found on chromosome 19. It is important for removing excess cholesterol from the blood, and does so by carrying cholesterol to receptors on the surface of liver cells. Defects in apolipoprotein E sometimes result in its inability to bind to the receptors, which leads to an increase a person's blood cholesterol and consequently their risk of atherosclerosis. Currently, a debate is raging over how the various mutated forms of apolipoprotein E affect the body. As a result, many of the treatments proposed remain in their experimental phase. For example, gene therapy is always a theoretical option in "curing" the disease; you would have to replace the mutated gene out with a fully functioning one. In this case, the gene would be located on chromosome 19, specifically the one coded for the protein call apolipoprotein. While mice are proving useful for modeling the human disease, a great deal of research is still required before we can fully understand the mechanisms that regulate the levels of lipoproteins—like apolipoprotein E—in the blood.
- Eating a healthy diet low in cholesterol and triglycerides. The diet should be high in fruits and vegetables.
- Exercising regularly. Physical activity can lower blood pressure and help control weight.
- Maintaining a desirable body weight.
- Stopping--or never starting--to use tobacco. Even people who smoke can reduce their risk of atherosclerosis by giving up the habit.
- Seeking treatment for hypertension. Hypertension is another name for high blood pressure. High blood pressure is probably a hereditary condition, but it can be brought under control by certain changes in lifestyle. These changes include reducing the amount of sodium and fat in the diet, exercising, learning how to manage stress, giving up smoking, and drinking alcohol in moderation.
A protein called apolipoprotein E, which can exist in several different forms, is coded for by a gene found on chromosome 19. It is important for removing excess cholesterol from the blood, and does so by carrying cholesterol to receptors on the surface of liver cells. Defects in apolipoprotein E sometimes result in its inability to bind to the receptors, which leads to an increase a person's blood cholesterol and consequently their risk of atherosclerosis. Currently, a debate is raging over how the various mutated forms of apolipoprotein E affect the body. As a result, many of the treatments proposed remain in their experimental phase. For example, gene therapy is always a theoretical option in "curing" the disease; you would have to replace the mutated gene out with a fully functioning one. In this case, the gene would be located on chromosome 19, specifically the one coded for the protein call apolipoprotein. While mice are proving useful for modeling the human disease, a great deal of research is still required before we can fully understand the mechanisms that regulate the levels of lipoproteins—like apolipoprotein E—in the blood.