Atherosclerosis is a type of arteriosclerosis. The name comes from the Greek words athero (meaning gruel or paste) and sclerosis (hardness). It's the term for the process of fatty substances, cholesterol, cellular waste products, calcium and fibrin (a clotting material in the blood) building up in the inner lining of an artery. The buildup that results is called plaque.
Arteriosclerosis is a general term for the thickening and hardening of arteries. Some hardening of arteries normally occurs when people grow older.
Plaque may partially or totally block the blood's flow through an artery. Two things that can happen where plaque occurs are:
- There may be bleeding (haemorrhage) into the plaque.
- A blood clot (thrombus) may form on the plaque's surface.
If either of these occurs and blocks the whole artery, a heart attack or stroke may result.
Atherosclerosis affects large and medium-sized arteries. The type of artery and where the plaque develops varies with each person.
Atherosclerosis is a slow, progressive disease that may start in childhood. In some people this disease progresses rapidly in their third decade. In others it doesn't become threatening until they're in their 50s or 60s.
How does atherosclerosis start?
It's a complex process. Exactly how atherosclerosis begins or what causes it isn't known, but some theories have been proposed. Many scientists think atherosclerosis starts because the innermost layer of the artery becomes damaged. This layer is called the endothelium. Three possible causes of damage to the arterial wall are:
- Elevated levels of cholesterol and triglyceride in the blood
- High blood pressure
- Cigarette smoke
Cigarette smoke greatly aggravates and speeds up the growth of atherosclerosis in the coronary arteries, the aorta and the arteries of the legs.
Because of the damage, over time fats, cholesterol, platelets, cellular debris and calcium are deposited in the artery wall. These substances may stimulate the cells of the artery wall to produce still other substances. This results in more cells accumulating in the innermost layer of the artery wall where the atherosclerotic lesions form. These cells accumulate, and many of them divide. At the same time, fat builds up within and around these cells. They also form connective tissue.
The innermost layer of the artery becomes markedly thickened by these accumulating cells and surrounding material. If the wall is thickened sufficiently, the diameter of the artery will be reduced and less blood will flow, thus decreasing the oxygen supply.
Often a blood clot forms and blocks the artery, stopping the flow of blood. If the oxygen supply to the heart muscle is reduced, a heart attack can occur. If the oxygen supply to the brain is cut off, a stroke can occur. And if the oxygen supply to the extremities occurs, gangrene can result.
Treatment
Treatments for atherosclerosis may include lifestyle changes, medicines, and medical procedures or surgery.
Goals of Treatment
The goals of treatment are to:
- Relieve symptoms
- Reduce risk factors in an effort to slow, stop, or reverse the buildup of plaque
- Lower the risk of blood clots forming
- Widen or bypass clogged arteries
- Prevent diseases related to atherosclerosis
Lifestyle Changes
Making lifestyle changes can often help prevent or treat atherosclerosis. For some people, these changes may be the only treatment needed.
- Follow a healthy eating plan to prevent or reduce high blood pressure and high blood cholesterol and to maintain a healthy weight.
- Increase your physical activity. Check with your doctor first to find out how much and what kinds of activity are safe for you.
- Lose weight, if you're overweight or obese.
- Quit smoking, if you smoke. Avoid exposure to second-hand smoke.
- Reduce stress.
Follow a Healthy Eating Plan
For a healthy eating plan less than 7 percent of your daily calories should come from saturated fat. This kind of fat is mainly found in meat and poultry, including dairy products. No more than 25 to 35 percent of your daily calories should come from all fats, including saturated, trans-, monounsaturated-, and polyunsaturated fats.
You also should have less than 200 mg a day of cholesterol. The amounts of cholesterol and the different kinds of fat in prepared foods can be found on the Nutrition Facts label.
Foods high in soluble fibre also are part of a healthy eating plan. They help block the digestive track from absorbing cholesterol. These foods include:
- Whole grain cereals such as oatmeal and oat bran
- Fruits such as apples, bananas, oranges, pears, and prunes
- Legumes such as kidney beans, lentils, chick peas, black-eyed peas, and lima beans
A diet high in fruits and vegetables can increase important cholesterol-lowering compounds in your diet. These compounds, called plant stanols or sterols, work like soluble fibre.
Fish are an important part of a heart healthy diet. They're a good source of omega-3 fatty acids, which may help protect the heart from blood clots and inflammation and reduce the risk for heart attack. Try to have fish about twice a week. Fish high in omega-3 fats are salmon, tuna (canned or fresh), and mackerel.
You also should try to limit the amount of sodium (salt) that you eat. This means choosing low-sodium and low-salt foods and "no added salt" foods and seasonings at the table or when cooking. The Nutrition Facts label on food packaging shows the amount of sodium in the item.
Try to limit drinks with alcohol. Too much alcohol will raise your blood pressure and triglyceride level. (Triglycerides are a type of fat found in the blood.) Alcohol also adds extra calories, which will cause weight gain. Men should have no more than two drinks containing alcohol a day. Women should have no more than one drink containing alcohol a day.
Dietary Approaches to Stop Hypertension
Try to focus your eating plan on fruits, vegetables, whole grains, and other foods that are heart healthy and lower in salt/sodium. Try eating fat-free or low-fat milk and dairy products, fish, poultry, and nuts. Reduce red meats to only twice weekly. Further reduce the intake of sweets, added sugars, and sugar-containing beverages.
Increase Physical Activity
Regular physical activity can lower many atherosclerosis risk factors, including LDL ("bad") cholesterol, high blood pressure, and excess weight. Physical activity also can lower your risk for diabetes and raise your levels of HDL cholesterol (the "good" cholesterol that helps prevent atherosclerosis).
Check with your doctor about how much and what kinds of physical activity are safe for you. Unless your doctor tells you otherwise, try to get at least 30 minutes of moderate-intensity activity on most or all days of the week. You can do the activity all at once or break it up into shorter periods of at least 10 minutes each.
Moderate-intensity activities include brisk walking, dancing, bowling, bicycling, gardening, and housecleaning.
More intense activities, such as jogging, swimming, and various sports, also may be appropriate for shorter periods.
Maintain a Healthy Weight
Maintaining a healthy weight can decrease your risk factors for atherosclerosis. A general goal to aim for is a body mass index (BMI) of less than 25. BMI measures your weight in relation to your height and gives an estimate of your total body fat.
A BMI between 25 and 29 is considered overweight. A BMI of 30 or more is considered obese. A BMI of less than 25 is the goal for preventing and treating atherosclerosis. Your doctor or other health care provider can help you determine an appropriate goal for you.
Quit Smoking
If you smoke or use tobacco, quit. Smoking can damage and tighten blood vessels and raise your risk for atherosclerosis.
Reduce Stress
Research shows that the most commonly reported "trigger" for a heart attack is an emotionally upsetting event—particularly one involving anger. Also, some of the ways people cope with stress, such as drinking, smoking, or overeating, aren't heart healthy.
Physical activity can help relieve stress and reduce other atherosclerosis risk factors. Many people also find that meditation or relaxation therapy helps them reduce stress.