Saturday, December 5, 2009

The Role of Cholesterol in a Heart Attack

At what levels should I be alarmed by my total cholesterol?

Total cholesterol should be less than 200 but it depends on the composite health picture of the patient, ie , how many other risk factors are present. We look at the good and bad cholesterol more than the total cholesterol. Here are some heart healthy good cholesterol and bad cholesterol numbers suggested by the American Heart Association.

What is the difference between good cholesterol and bad cholesterol?

Good cholesterol or HDL (high density lipoprotei ) helps protect against heart disease. Bad cholesterol or LDL (low density lipoprotein) and is associated with heart disease. 

How do each of these cholesterol types operate to help fight or cause the heart disease?

LDL transports cholesterol and invades the endothelium or lining of the blood vessels. When too much LDL (bad) cholesterol circulates in the blood, it can slowly build up in the inner walls of the arteries that feed the heart and brain. Together with other substances, it can form plaque, a thick, hard deposit that can narrow the heart arteries and make them less flexible. This condition is known as atherosclerosis.

HDL transports cholesterol from the arteries to the liver where it can be eliminated from the body. Some experts believe that that HDL removes excess cholesterol from arterial plaque, thus slowing its buildup.

How low is too low for the levels of good cholesterol?

HDL of less than 40 is too low for men1, and less than 50 is too low for women2.

What can be done to lower bad cholesterol?

Exercise, diet, weight loss, eating less animal fats, using cholesterol lowering medications such as statins , cholestyramine, and ezetemibe.3.

What can be done to raise good cholesterol?

Niacin, fenofibrates, fish oil, exercise, weight loss.

What are the differences between the advertised cholesterol lowering drugs?

Cholesterol lowering medications include
Statins
Ezetimibe
Fibrates
Bile acid binding resins
Niacin


Statins are the most commonly used medications. They are in the class known as HMG CO-A reductase inhibitors. They work by blocking the production of the cholesterol in the liver. They are highly effective at lowering total cholesterol and LDL cholesterol. They also lower triglycerides and modestly raise HDL, the good cholesterol.. They have been used since the 1980s and overall are considered to be safe. They include Pravachol, Lipitor, Zocor, Lescol, Mevacor, and Crestor.

Crestor is a very powerful statin that has been shown to reduce LDL cholesterol better than any of the other statins. However, at higher dosages 40 mg or more, it has been shown to have a slightly higher than expected amount of muscle inflammation associated with it.

Side effects of statins may include nausea, malaise, elevation of liver tests and muscle aches or cramps.

Zetia, or ezetimibe, works by inhibiting cholesterol absorption in the intestine.

It lowers cholesterol modestly (15-20% compared with statins at 35%) when taken on its own. It is often used in combination with a statin thereby providing patients with a dual mechanism of reduction of cholesterol to further reduce LDL in those patients who are not yet at their goal cholesterol, despite being on a statin.

The side effect profile of ezetimibe is essentially similar to placebo, based on the medical literature; however, some patients will complain of abdominal discomfort. In the overwhelming majority of patients, however, no side effects are noted.

Fibrates lower the production of triglycerides and can increase HDL production. Some brand names are Lopid, Tricor and Atromid. Side effects may include heart burn, abdominal pain, bowel movement changes, elevated liver enzymes, and muscle aches.

Bile acid resins such as Questran, Colestid, WelChol work inside the intestine. They bind bile from the liver that is flowing into the intestine and prevent it from being reabsorbed into the circulatory system. Bile is made largely from cholesterol, so these drugs work by depleting the body's supply of cholesterol. The most common side effects are constipation, gas and upset stomach.

Niacin is a B-complex vitamin which in high doses in prescription form (Niaspan) lowers LDL and raises HDL.

The side effects of flushing, itching, tingling, and headache can be severe. These symptoms may be reduced if the dose of niacin is raised slowly and if it is taken at night with food and if aspirin 165 mg is taken about 30 minutes before taking the niacin. It is also reported to help if it is taken with a cup of yogurt.

Are there everyday things I should avoid if I am on some of these drugs?

Grapefruit juice increases the levels of the statins and it is best avoided. Alcohol consumption should be discussed with your doctor.

What are fenofibrates and where would you get them?

They are another class of cholesterol lowering medications which are given by prescription.

After one heart attack how likely is it the patient will have another?

This is unknown, but having one heart attack does increase the risk of having another episode.