Cholesterol is a type of lipid (fat) that's used by the body to make hormones and vitamin D and aid in the digestion of food. The liver makes about 1,000 milligrams of cholesterol/day. We also get cholesterol in our diet. The main sources of dietary cholesterol are animal products, like meats, milk and eggs.

Cholesterol is transported in the blood in the form of a protein package, called a lipoprotein. There are two important forms of lipoproteins. LDL, or low-density lipoprotein, circulates in the blood and deposits itself along the walls of the arteries. HDL, or high-density lipoprotein, picks up LDL cholesterol and carries it back to the liver for processing. LDL is often considered the "bad" cholesterol. When there are high levels of LDL in the blood, the excess builds along the inner walls of the arteries. It mixes with other substances in the blood to form thick, hardened deposits known as plaque (a disease process known as atherosclerosis). As the plaque builds, the affected area of the artery narrows, slowing the flow of blood. The artery can become completely blocked when a blood clot becomes trapped in the narrowed artery or when the plaque closes off the artery. The part of the body fed by the affected artery is deprived of oxygen and the tissue dies. In the heart, artery blockage leads to a heart attack. In the brain, it causes a stroke.

Doctors currently recommend cholesterol screening at least every five years for everyone 20 and older. Ideal total cholesterol levels for adults are less than 200 mg/dL. Total cholesterol levels of 200 to 239 mg/dL are considered borderline high and levels of 240 mg/dL are high. Experts also recommend measurement of HDL and LDL since those lipoproteins are important factors in the development of atherosclerosis. Optimal levels of LDL are less than 100 mg/dL. Levels of 160-89 mg/dL of LDL are high and 190 mg/dL and above are very high. Higher levels of HDL are considered protective for heart disease. Ideal HDL levels should be 60 mg/dL or higher. HDL levels of 40 mg/dL or lower are considered a major risk factor for heart disease.

Treating High LDL Cholesterol
There are several treatments that can be used to lower LDL. Initially, doctors recommend a cholesterol-lowering diet, weight management and a program of regular physical activity. Some patients may also need medications that lower LDL cholesterol levels and/or raise HDL levels.

In some cases, LDL levels remain elevated despite several different treatment methods. About one in 500 people have a condition called familial hypercholesterolemia, which is characterized by high LDL levels. Patients typically develop significant or severe heart disease by their 30s or 40s. One treatment that may be useful for these patients and others with very high, untreatable LDL cholesterol is called apheresis.

LDL Apheresis
Apheresis is a process where certain components of the blood are removed. The process is similar to dialysis for the kidneys. Blood is drained through an IV line into a special machine which removes the blood plasma (the watery portion in which cholesterol travels). The remaining blood components are mixed with a replacement plasma or saline solution and put back into the body through another IV line. The treatment occurs in a continual process over several hours.

Standard apheresis can help lower cholesterol, but the treatment also filters out the good (HDL) cholesterol, important antibodies and clotting factors. However, some newer machines specifically target the LDL cholesterol. During LDL apheresis, the blood is passed through a special filter. As the blood flows through the filter, LDL cholesterol is bound to a column of special material that attracts the lipoprotein. Everything else passes through the filter and is given back to the patient. Treatment lasts about three to four hours.

Research shows LDL apheresis can reduce LDL cholesterol levels by up to 80 percent. Studies also find patients have reduced levels of chest pain, decreased plaque volume and a 50 percent decrease in the incidence of coronary events. Since the body continues to make cholesterol, the treatment must be repeated about every two to four weeks.

Doctors say LDL apheresis is an expensive procedure that's typically reserved for patients who are unable to lower their cholesterol levels despite several different attempts at treatment. The therapy may also be advised for patients who are unable to tolerate cholesterol-lowering medications.

AUDIENCE INQUIRY
For information about high cholesterol or heart disease:
American Heart Association, http://www.americanheart.org, or contact your local chapter
National Heart, Lung and Blood Institute, http://www.nhlbi.nih.gov

Source: Medstar