A Disease of Atherosclerosis and Its Prevention

Atherosclerosis is a disease of the heart caused by fat deposits in the walls of blood vessels, mainly the arteries. Atherosclerosis can occur in any artery, but it usually occurs in larger arteries around the area where they branch. The place where atherosclerosis is found most commonly is in the coronary arteries. This disease can occur in anyone, but most commonly is found in males, smokers, people with high cholesterol levels, and people who do not exercise frequently.

Atherosclerosis can be found in some people in their late teens. It begins as small streaks of fat deposits just underneath the smooth lining of the arteries. Over time, the streaks of fat deposits become accumulations of fat, or plaque. Once plaques have become large enough to project into the artery, they break or crack. When this happens, the blood begins to clot over the plaque, obstructing the artery. A piece of the plaque may break off while in a large artery, and be carried through the bloodstream to a smaller vessel. When this blockage occurs, it is called an embolism. This process, caused by fat deposits, or plaque, often completely block a coronary artery, causing a heart attack.

There is no known reason as to why some people develop atherosclerosis and some people do not. There are, however, several risk factors associated with developing the disease. Some risk factors can be altered to be less at risk for developing atherosclerosis, while some factors cannot be changed. Age, heredity, and gender are risk factors that cannot be changed to lessen the risk of developing the disease. Risk factors that can be altered are smoking, cholesterol levels, obesity, and exercise.

High cholesterol levels in the blood increase the risk of developing atherosclerosis. Cholesterol is a normal fat found in the body, and makes up part of cell membranes and different types of hormones. In the bloodstream, cholesterol mixes with protein to form a lipoprotein. This allows the cholesterol to dissolve. There are two types of lipoproteins, LDL (low-density lipoprotein) and HDL (high-density lipoprotein). LDL is the lipoprotein that is responsible for supplying the cholesterol that forms plaques. LDL is often referred to as the "bad cholesterol". HDL takes cholesterol from different sites in the body to the liver, where it is disposed of. It is often referred to as the "good cholesterol" because it removes excess cholesterol from the body.

People with high levels of LDL are twice as likely to die from heart disease. If steps are taken to lower the cholesterol levels, the person's risk drops dramatically. If a person drops his/her cholesterol level by 15%, the risk of a heart attack is reduced by up to 30%. Smoking is a significant risk factor that can be altered. Smoking reduces the amount of HDL in the body, while increasing the amount of LDL. This increases the formation of plaques. Smoking also raises the pulse and narrows the coronary arteries. This increases the amount of work that the heart has to perform. Smokers are twice as likely to develop atherosclerosis. For heavy smokers, the risk triples. After a smoker quits, their risk for developing atherosclerosis drops to normal after about 2 years. High blood pressure also contributes to developing atherosclerosis. High blood pressure also increases the workload of the heart. When blood pressure is controlled, the risk of developing atherosclerosis is reduced to normal. Obesity is a risk factor for several reasons. For people who are 20% over their ideal weight, the risk of developing atherosclerosis increases by 50%. The heart has to work extra hard to pump blood through the extra tissue created by obesity. Regular exercise has been shown to increase the levels of HDL in the body, and at the same time decreasing the levels of LDL. Over time, exercise strengthens the heart. People who have already developed atherosclerosis can reduce the severity of plaques in the body by exercising regularly.

Atherosclerosis can also cause thrombosis and aneurysms. Thrombosis is a formation of a blood clot in the circulatory system. Blood does not usually clot inside a blood vessel because of the substances within the blood vessel that prevent clotting. Atherosclerosis damages the blood vessel surface, and the substances are no longer present. The rough surface of the plaque signals the clotting factors in the blood, and forms a clot over the damaged area. The clot actually narrows the blood vessel more than the plaque does. If the clot obstructs the artery completely, the tissues that the artery serves will be deprived of oxygen. Pieces of the clot can also break off and form embolisms in smaller vessels. People at high risk for heart attacks and strokes often take blood thinners for this reason. If atherosclerosis damages the wall of a blood vessel enough for it to lose its strength, an aneurysm develops. The pressure in the blood vessels causes the weakened area to stretch, which forms swollen "pouch". Aneurysms can occur anywhere in the body, but are most commonly found in abdomen where the aorta is located.

Atherosclerosis is often a preventable disease, but some risk factors cannot be changed. Atherosclerosis often is associated with many other diseases of the heart, and can cause many different problems. By regulating cholesterol levels, weight management, not smoking, and regular exercise, a person can put themselves at a lower risk than people who do the opposite.