Coronary Artery Disease

Coronary artery disease, also called simply heart disease, is a condition in which the coronary arteries (the blood vessels that supply blood to the heart muscle) become blocked, cutting off blood flow and, therefore, oxygen to the heart muscle. This damages the heart, causing it to malfunction. Coronary artery disease is the leading cause of death in the United States for both men and women. Nearly 20 percent of men aged 65 to 69 have had a heart attack, and nearly 30 percent of men aged 80 to 84 have had a heart attack. Nearly half of all men who die of coronary artery disease are not aware that they have the disease.

The following risk factors increase your risk of developing heart disease:

  • Family history. Your chances of having coronary artery disease are much greater if either of your parents had heart disease before age 65.
  • High blood pressure. This condition makes the heart pump harder, increasing the size of the heart muscle and, thereby, the chance of heart failure; it can directly damage coronary arteries.
  • Smoking. Smokers have a 70 percent greater chance of developing coronary artery disease than nonsmokers.

High cholesterol levels. High levels of cholesterol in the bloodstream lead to the formation of fatty deposits in the walls of the coronary arteries, causing them to narrow and obstruct blood flow.

  1. Excess weight puts added strain on the heart, increases the risk of high blood pressure, and leads to higher levels of cholesterol in the blood. Inactivity. Regular exercise helps control cholesterol levels and weight. It also helps keep the heart strong and healthy.
  2. More than 80 percent of people with diabetes die of some form of blood vessel or heart disease.

Heart, Blood, and Circulation

Atherosclerosis

The heart receives its blood supply from the three coronary arteries that leave the aorta just outside the left ventricle. Like a tree, these three major arteries divide into smaller and smaller blood vessels until the entire heart wall is penetrated by hundreds of tiny blood vessels.

Coronary artery disease is caused by various gradual changes that occur in the coronary arteries. Collectively these changes are referred to as arteriosclerosis, which means hardening and thickening (literally "scarring") of the wall. Atherosclerosis is the most common type of arteriosclerosis. Atherosclerosis is the gradual thickening and hardening of an artery's inner wall by the formation of fatty deposits called plaques. These plaques cause narrowing of the artery's internal channel, thereby reducing the flow of blood (and oxygen) to the heart. This is similar to the way layers of minerals form a deposit inside a water pipe; as the minerals accumulate, the stream of water becomes steadily smaller.

Atherosclerosis

Atherosclerosis is the buildup of a cholesterol-containing substance called plaque inside arteries. Plaque often has a fatty core with a hard coating.The buildup of plaque can reduce or block the flow of blood to vital organs.

Atherosclerosis

Atherosclerosis is the buildup of a cholesterol-containing substance called plaque inside arteries. Plaque often has a fatty core with a hard coating.The buildup of plaque can reduce or block the flow of blood to vital organs.

Plaque and Blood Clots

A buildup of plaque inside an artery is often the start of a blood clot. Plaque tends to crack (top).Your body interprets these cracks as injuries and forms blood clots around them to seal them and allow them to heal (center). If a clot inside a coronary artery grows large enough (bottom), it can block blood flow in the artery and cause a heart attack.

Plaque and Blood Clots

A buildup of plaque inside an artery is often the start of a blood clot. Plaque tends to crack (top).Your body interprets these cracks as injuries and forms blood clots around them to seal them and allow them to heal (center). If a clot inside a coronary artery grows large enough (bottom), it can block blood flow in the artery and cause a heart attack.

Common

Health

Concerns

As the plaques become thicker, their surface becomes rougher. This encourages formation of blood clots within the artery. Small pieces of a blood clot can break off and travel through the bloodstream and block smaller blood vessels, causing a heart attack or stroke.

Atherosclerosis occurs more commonly in the coronary arteries than in other arteries of the body. The thickening of the artery wall progresses slowly until only a trickle of blood moves through the narrowed channel. The process may continue at the same rate until a small artery has been closed completely. As the artery gradually closes, the blood supply to the heart muscle becomes inadequate, causing heart damage.

Coronary artery disease is the most common result of an inadequate blood supply to the heart muscle. The most common symptom of coronary artery disease is angina (see below); the most serious consequence is a heart attack.

Angina

Angina is temporary moderate to severe pain or pressure in the chest. Sometimes the pain extends to the left shoulder and down the left arm or to the throat, jaw, and lower teeth. Occasionally it will reach the right side of the body. Many people describe their symptoms as discomfort rather than pain. Angina is caused by a lack of oxygen to the heart muscle.

Healthy coronary arteries can readily meet the heart's demands for oxygen. However, if the coronary arteries have become narrowed or hardened as a result of atherosclerosis, they cannot supply adequate blood to the heart muscle during times of increased demand, resulting in angina.

Angina associated with coronary artery disease usually occurs during times of exertion, emotional stress, or after a large meal, when the heart pumps faster and harder, trying to keep up with the body's increased oxygen demands. Often angina is worse when exertion follows a meal. Angina usually is worse in cold weather; walking into the wind or moving from a warm room to the cold air outdoors can trigger angina.

An episode of angina usually lasts fewer than 15 minutes and subsides with rest. Symptoms of angina that last longer than this may actually be a heart attack in progress, and you should seek immediate help. (See "Warning Signs of a Heart Attack," page 209.) Since heart disease develops unnoticed in many people, angina is considered to be a beneficial warning sign. If you experience angina, see your doctor as soon as possible.

Unstable angina refers to angina in which the established pattern of symptoms changes, or suddenly worsens. For example, angina pain usually remains constant and predictable from one episode to the next. But with unstable angina, the person may experience unpredictable changes, such as more severe pain, more frequent attacks, or attacks occurring with less exertion or during rest. These kinds of changes usually signal a rapid progression of coronary artery disease, with increasing blockage of the coronary artery, possibly because a blood clot has formed or a piece of plaque has broken away from the artery wall. The risk of heart attack is high. Unstable angina is a medical emergency that requires immediate treatment.

Although angina is most often caused by coronary artery disease, it also can result from other factors, such as defects in the aortic valve. Because the aortic valve is near the opening of the coronary arteries, these abnormalities may reduce blood flow into the coronary arteries and limit the amount of oxygen that goes to the heart. Another possible cause of angina is arterial spasm, in which, for reasons not fully understood, sudden temporary constriction or spasms occur in a coronary artery. Also, severe anemia (see page 238) may reduce the supply of oxygen to the heart, resulting in angina. Not everyone with an inadequate blood supply to the heart muscle experiences angina. Doctors do not yet understand why.

Angina is usually easy to recognize, but there are times when it mimics other conditions unrelated to the heart and blood vessels, such as indigestion and gas-troesophageal reflux disease (GERD; see page 262). Diagnosis can often be made by a physical examination and an exercise stress test (which evaluates heart rate, blood pressure, electrical activity of the heart, and symptoms of angina and other problems related to inadequate blood supply to the heart while a person walks or runs on a treadmill or rides a stationary bicycle).

Treatment for angina includes learning to reduce and deal positively with stress, decreasing cholesterol intake, and losing weight if you are overweight. A wide variety of medications are available that reduce blood pressure, slow the heart rate, or widen the blood vessels. In addition, other medications are available that can help prevent the buildup of plaque in the arteries. If necessary, surgical procedures can be performed to bypass, clear, or widen the diseased coronary arteries.

Heart, Blood, and Circulation

Heart Attack

A heart attack is sudden death of a portion of the heart muscle that has been deprived of its blood supply. Most heart attacks are caused by blockage of a coronary artery. The blockage may be caused by a slow-growing plaque (fatty deposit) that blocks blood flow in the artery or by a quicker event, such as when a plaque ruptures or tears, causing a blood clot to form and clog the artery. Nearly 95 percent of sudden heart attacks are caused by a ruptured plaque and subsequent blood clot formation, which slows or prevents blood flow to the heart muscle.

When a blood clot forms on the rough surface of a plaque in the arterial wall, blocking an artery completely and suddenly, the result is often a sudden heart attack. Doctors also call this a "coronary thrombosis" or a "coronary occlusion." Heart damage occurs very quickly following blockage of a coronary artery. The

Common

Health

Concerns affected heart tissue begins to deteriorate, and damage becomes permanent after about 6 minutes. This is why the speed of response to a heart attack is critical. The more quickly a person is treated, the better the chances of limiting damage to the heart.

For the heart muscle to function properly, it needs a continuous supply of oxygen-rich blood from the coronary arteries. The body has a remarkable ability to adapt to changing conditions—even narrowing of the coronary arteries—to ensure this continuous supply of blood. For example, if an artery starts to close gradually by thickening of its inner lining, and sometimes if it is closed by a blood clot, neighboring arteries gradually increase in size and send out new branches to supply adequate blood to the threatened area. This process is known as the formation of "collateral circulation."

In most cases, when a blood clot blocks a branch of the coronary artery, the symptoms appear suddenly, although it may take minutes, hours, or even days for the clot to grow large enough to block the artery. The time required for blockage to occur depends on the width of the channel inside the artery. If the artery is small and has narrowed gradually over a period of years, so that good collateral circulation is already present, blockage by a blood clot may cause mild symptoms or none at all. On the other hand, if the artery is large and there has been only slight narrowing, sudden obstruction by a blood clot may cause severe discomfort.

Rarely, a heart attack may occur when a clot from another part of the heart breaks away and lodges in the coronary artery. Another uncommon cause of a heart attack is a spasm in a coronary artery that stops blood flow. The causes of such spasms are usually unknown.

The symptoms and extent of a heart attack depend on factors such as the size of the blocked artery, the width of the channel inside the artery, the suddenness of the blockage, the extent to which an adequate collateral circulation has formed, and the general condition of the heart at the time of the attack.

The pain of a heart attack is usually, but not always, severe. Like angina, the pain occurs in the center of the chest and may spread to the back, left arm, or jaw; less often the pain spreads to the right arm. Because many people have strong denial capabilities ("It can't be happening to me!"), they may downgrade the severity of the pain and attribute it to some other cause, such as indigestion. Other symptoms of a heart attack include a heavy pounding of the heart, feeling faint or fainting, restlessness or anxiety, and sweating. The lips, hands, or feet may turn slightly blue. Older people may become disoriented or confused. Irregular heartbeats (arrhythmia) may seriously interfere with the heart's ability to pump effectively and may precede a heart attack.

Two of three people who have heart attacks experience intermittent chest pain, shortness of breath, or fatigue a few days beforehand. Some people may think these symptoms are nothing more than an angina episode. The key is to be able to recognize the difference between angina and the pain caused by a heart attack, which is usually more severe, lasts longer, and does not go away with rest or after taking nitroglycerin.

One of five people who have a heart attack has only mild symptoms or none at all. Such "silent" heart attacks are often diagnosed after the fact through a routine electrocardiogram (ECG; an examination of the electrical activity of the heart). Many of these silent attacks go unnoticed because they affect a less crucial part of the heart or because the person having the attack may have an unusually high tolerance for pain.

Heart, Blood, and Circulation

Warning Signs of a Heart Attack

Become familiar with the warning signs of a heart attack so you can seek immediate help if you or someone you know begins to experience them. The most common symptoms of a heart attack include:

  • sudden, strong pain, pressure, fullness, or squeezing in the center of the chest that lasts more than just a few minutes and is not relieved by rest
  • chest pain that spreads to the shoulders, neck, jaw, or arms
  • chest discomfort accompanied by shortness of breath, light-headedness or fainting, sweating, cold or clammy skin, nausea or vomiting, or loss of consciousness

Less common heart attack symptoms are:

  • other kinds of chest pain or stomach or abdominal pain
  • unexplained anxiety, weakness, or fatigue
  • palpitations, a cold sweat, or pale skin

A heart attack is a medical emergency. If you have any of the symptoms described above, call 911 or your local emergency number, or call an ambulance service, and ask for immediate transportation to a hospital emergency department. If you are with a person who has any of these symptoms, call 911 or your local emergency number, or take him or her to the nearest hospital emergency department without delay.

Other conditions may mimic a heart attack. These conditions include pneumonia, a blood clot in the lung (pulmonary embolism), inflammation of the membrane that surrounds the heart (pericarditis), fracture of a rib, spasm of the esophagus, indigestion, gastroesophageal reflux disease, and chest muscle tenderness after injury or exertion. An ECG and measurement of certain enzymes in the blood can confirm the diagnosis of a heart attack within a few hours. In many instances, an ECG can show when a person is having a heart attack. Several abnormalities may appear on the ECG, depending on the extent and the location of heart muscle damage. If a person has had a previous heart attack, however, the current heart muscle damage may be difficult to detect. If the results of a few

Common

Health

Concerns

ECGs taken over the course of several hours are normal, the doctor usually considers a heart attack less likely but will wait for the results of blood enzyme tests before making a diagnosis.

The levels of certain enzymes in the blood can be measured to help diagnose a heart attack. For example, an elevated level of heart-muscle enzymes called troponins in the blood is an indication of damage to the heart muscle that results from a heart attack. The level of troponins increases about 4 to 6 hours after a heart attack, peaks 10 to 24 hours after the attack, and can be detected in the blood for about a week. Troponin levels are usually checked when a person is admitted to the hospital with chest pain and a possible heart attack and at 8-hour intervals for about 24 hours.

Another heart-muscle enzyme, called CK-MB, is also released into the blood when heart muscle is damaged. Elevated levels show up in the blood within 6 hours of a heart attack and they persist for 36 to 48 hours. Levels of CK-MB usually are checked when the person is admitted to the hospital and at 6- to 8-hour intervals over the next 24 hours.

If ECG and enzyme test results do not provide enough information to diagnose a heart attack, imaging techniques such as echocardiography (an ultrasound examination of the heart) or radionuclide scanning (see page 213) may be performed. An echocardiogram may show reduced motion in part of the wall of the left ventricle (the part of the heart that pumps blood to the body), suggesting damage from a heart attack. A radionuclide scan may show a persistent reduction in blood flow to a specific area of the heart muscle, suggesting a scar (dead tissue) caused by a heart attack.

Why You Should Take CPR Training

Cardiopulmonary resuscitation (CPR) is a critically important technique that could help you save the life of someone you love. CPR is used to revive a person when his or her breathing or heartbeat stops—a sign of sudden death. Sudden death can be caused by a number of events, including a heart attack, poisoning, drowning, choking, suffocation, electrocution, and smoke inhalation. The CPR procedures attempt to restart the person's breathing and heartbeat, employing techniques that keep the person's airway open, use rescue breathing to administer oxygen, and apply rhythmic pressure to the chest to force the heart to pump blood. Use CPR until emergency medical personnel arrive.

Your local hospital or fire department, the local chapters of the American Red Cross or the American Heart Association, or your employer all may offer CPR training courses. Ask your doctor about CPR classes in your community. Take advantage of these opportunities for training because your knowledge could make the difference between life and death for someone. Once you learn the CPR procedures, practice them often so you won't forget the correct procedures when you need them the most. CPR should be performed only by people trained in this procedure.

When dealing with a possible heart attack, speed is vital. Half of the deaths caused by heart attacks occur within the first 3 or 4 hours after symptoms begin. The faster a heart attack victim gets to a hospital emergency department, the better the chances of survival. Anyone experiencing symptoms of a possible heart attack (see "Warning Signs of a Heart Attack," page 209) should seek immediate medical attention. If aspirin is available, encourage the person to swallow one tablet. Aspirin helps reduce the blood's tendency to clot, thereby reducing the chances of dying of a heart attack by 20 percent.

A person suspected of having a heart attack is usually admitted to a hospital's cardiac care unit (CCU). In the CCU, a person's heart rhythm and blood pressure and the amount of oxygen in the blood are closely monitored to assess heart damage. Nurses in these units are specially trained to deal with cardiac emergencies. Upon arrival, the patient is immediately given a thrombolytic (clot-dissolving) medication such as tissue plasminogen activator (tPA), streptokinase, or urokinase. These drugs are most effective if given within 6 hours of the start of the heart attack symptoms. If a blocked coronary artery can be cleared quickly, damage to heart tissue may be prevented or limited. After 6 hours, restoring blood flow to the heart does not help very much. Early treatment with thrombolytic drugs can increase blood flow and limit heart tissue damage. Aspirin, which prevents platelets from forming blood clots, or heparin, which also stops clotting, may enhance the effectiveness of treatment with thrombolytic drugs.

A beta-blocker drug also is given to slow down the heart rate and make the heart work less hard to pump blood through the body. Reducing the heart's workload also helps limit damage to the heart. Oxygen is given through a face mask, or via a tube with prongs inserted into the nostrils. This therapy increases the oxygen content in the blood, which provides more oxygen to the heart and helps to keep heart tissue damage to a minimum. Some physicians recommend coronary angioplasty (see page 216) to open the coronary arteries or coronary artery bypass surgery (see page 216) after a heart attack instead of treatment with thrombolytic drugs.

Depending on the extent of the heart attack, you may be released from the hospital for home rest within days. Your doctor will probably advise you to stay in bed and rest for several days and to avoid excitement, physical exertion, and emotional stress. If you smoke, your doctor will tell you to quit immediately (see page 107); smoking is a major risk factor for coronary artery disease and heart attack.

It is normal to feel anxious and depressed after a heart attack. Because severe anxiety can stress the heart, the doctor may prescribe a mild tranquilizer. To deal with the depression and with denial of illness, which also is common after a heart attack, patients and their families are encouraged to talk about their feelings with doctors, nurses, and social workers. Many hospitals where cardiac

Heart, Blood, and Circulation

Common

Health

Concerns

Sex and Heart Disease surgery is performed offer support groups in which people who have recovered from heart attacks or cardiac surgery have been trained to work as peer counselors for recuperating inpatients.

In general, most people who survive for a few days after a heart attack can expect to recover fully. However, about 10 percent, usually those who continue to have angina, irregular heart rhythm, or heart failure, will die within a year. Most of those deaths will occur within the first 3 to 4 months. To promote recovery and to help avoid possible future heart attacks, survivors usually are prescribed heart medications, cholesterol-lowering drugs (see "Medications for Heart Disease," page 214), a low-fat diet, and regular sessions of aerobic exercise in a cardiac rehabilitation program.

Men with heart disease face exceptional challenges to their sexuality. Distressing pain and other symptoms make it difficult to feel comfortable, much less sexually aroused. Many men with heart disease are afraid to have sex because they and their partner fear that the increased physical exertion could cause chest pain or even another heart attack. But most men with heart problems can have sex without causing any physical problems. Talking to your doctor about such a delicate subject can be uncomfortable, but you need to find out what your limits are. Even if your heart condition is so serious it restricts your ability to have intercourse, you still can be affectionate and intimate with your partner in other ways. For example, you could bring your partner to orgasm using your hand or mouth. Remember that heart disease should never prevent you from having a loving and caring relationship with your partner.

Managing Heart Disease

Once you are released from the hospital after a heart attack, your treatment will focus on long-range preventive care. Your doctor will recommend that you make lifestyle changes such as eating a healthy diet, exercising regularly, losing weight if you are overweight, and quitting smoking if you smoke. In addition, your doctor will want to monitor your condition with regularly scheduled checkups and tests, and he or she may prescribe medication to reduce risk factors for heart disease such as high blood pressure or high cholesterol level.

Tests for Heart Disease Physicians use a number of procedures to evaluate a person's risk for heart problems, the progress a person is making after a heart attack or surgery, and the status of a person's heart and circulatory system. These procedures include:

  • Continuous ECG monitoring of the heart's electrical activity with a Holter monitor. The monitor, which is worn around the neck or over the shoulder, records an ECG for 24 hours, so the doctor can monitor an arrhythmia (abnormal heartbeat) or episodes of silent ischemia (inadequate blood flow to the heart).
  • Exercise stress testing is an evaluation of heart rate, blood pressure, electrical activity of the heart, and symptoms of angina and other problems related to inadequate blood supply to the heart while a person walks or runs on a treadmill or rides a stationary bicycle. This test can help determine the severity of coronary artery disease and the ability of the heart to respond to a reduced blood supply. The test may be performed before or shortly after the person leaves the hospital to help determine how well he is doing after the heart attack and whether ischemia is continuing. If this test reveals an arrhythmia or ischemia, drug treatment may be recommended. If ischemia persists, a physician may recommend coronary arteriography to determine whether coronary angioplasty (see page 216) or coronary artery bypass surgery (see page 216) is needed to restore blood flow to the heart.

Radionuclide scanning combined with exercise stress testing may provide a physician with information about the person's angina. This test involves injecting a radioactive substance that travels through the bloodstream to a target organ and using a special camera to produce an image of that organ. Radionuclide scanning not only confirms the presence of ischemia but also identifies the area and the amount of heart muscle affected. Exercise echocardiography is a procedure in which ultrasound images of the heart (echocardiograms) are obtained while a person walks or runs on a treadmill. The test is harmless and shows heart size, movement of the heart muscle, blood flow through the heart valves, and valve function. Echocardiography is performed while the person is at rest and at the peak of exercise. When ischemia is present, the pumping motion of the wall of the left ventricle appears abnormal. Angiography allows blood vessels to be seen on film. A catheter (a thin, flexible tube) is usually inserted into the femoral artery, a large blood vessel in the groin area, and moved up through the aorta (the main artery in the body) and into the coronary arteries. A contrast medium (dye) is injected through the catheter into the artery to be examined, and a series of rapid-sequence X rays (similar to a movie) are taken. Narrowing and blood flow inside the arteries are clearly visible, allowing the physician to determine whether the arteries can be treated by bypass surgery or angioplasty. Occasionally angiography is used to detect spasm in coronary arteries that do not have any plaques. Certain medications are given to stimulate a spasm during the procedure to help diagnose the condition.

Computed tomography (CT) scanning, a diagnostic procedure in which a computer is used to construct

Heart, Blood, and Circulation

Common

Health

Concerns cross-sectional X-ray images of the heart and coronary arteries, helps to detect calcification in the artery walls, which is associated with atherosclerosis. A faster version of CT scanning is used to examine artery walls for structural and functional abnormalities associated with a heart attack.

Medications for Heart Disease Medications are available to improve blood flow and to minimize symptoms associated with coronary artery disease. The following four types of drugs are frequently used for treating heart disease:

  • Beta-blockers interfere with the effects of epinephrinelike hormones in the body that normally increase heart rate and blood pressure. Beta-blockers reduce the resting heart rate. During exercise they limit the increase in heart rate, decreasing the body's demand for oxygen. Beta-blockers lower the risk of heart attacks and sudden death for people with coronary artery disease. Beta-blockers are estimated to reduce the risk of cardiac death by about 25 percent when taken by people who have had a heart attack. The more serious the heart attack, the more benefit these drugs provide. Possible side effects include slow heartbeat, fatigue, and erectile dysfunction. Some examples of beta-blockers are atenolol, metoprolol, and propranolol.
  • Nitrate drugs such as nitroglycerin dilate (widen) the blood vessels, improving blood flow. Both short-acting and long-acting nitrates are available. A small tablet of nitroglycerin placed under the tongue usually relieves an episode of angina in 1 to 3 minutes. The effects of this short-acting nitrate drug last about 30 minutes. People with chronic stable angina are advised to carry nitroglycerin with them at all times. Some people learn through experience to take nitroglycerin just before reaching the level of exertion they know can induce their angina.

Long-acting nitrate drugs are taken one to four times daily. They are available as skin patches or as a paste, which is absorbed through the skin over many hours. Over time, long-acting nitrates lose their ability to provide relief. Most doctors recommend that people try going 8- to 12-hour periods without taking the drug, to help maintain its effectiveness. Possible side effects include headache, flushing of the skin, and dizziness.

  • Calcium channel blockers prevent blood vessels from constricting and interfering with blood flow. These drugs are also used to treat certain types of arrhythmias because they can slow the heart rate. Possible side effects include headache, flushing of the skin, and dizziness. Some examples of calcium channel blockers are amlodipine, diltiazem, and verapamil.
  • Anticlotting drugs such as aspirin are helpful. Platelets are cell fragments circulating in the blood that are necessary for clot formation during a bleeding episode or when blood vessels are injured. But when platelets collect on the surface of a plaque on an artery wall, the resulting clot formation (thrombosis) can narrow or block the artery and cause a heart attack. Aspirin binds to platelets and keeps them from clumping on blood vessel walls, reducing the risk of death from a blocked coronary artery. Regular aspirin use can reduce the risk of death and the risk of a second heart attack by 15 to 30 percent. People with a sensitivity to aspirin may take prescription medications that help prevent blood clots, such as dipyridamole and ticlopidine, as a substitute.

If you have heart disease and your cholesterol levels are high, your doctor may recommend that you take cholesterol-lowering medication. Different cholesterol-lowering drugs work in different ways. For example, some drugs decrease blood levels of LDL ("bad") cholesterol, while others increase levels of HDL ("good") cholesterol. Still others work by lowering triglyceride (another type of fat) levels in your blood. Your doctor will prescribe a particular medication for you, depending on your individual needs. You may need to take this medication for the rest of your life. Cholesterol-lowering medications include the following:

  • Bile acid-binding resins prevent absorption of cholesterol into the blood and stimulate the liver to remove cholesterol from the bloodstream. Possible side effects include bloating, cramping, and diarrhea. Examples of bile acid-binding resins include cholestyramine and colestipol.
  • Fibrates (also called fibric acid derivatives) decrease blood levels of triglycerides. These drugs also can decrease LDL cholesterol and moderately increase HDL cholesterol levels. People who take fibrates have a slightly increased risk of developing gallstones (see page 276) and gallbladder disease. Examples of fibrates include gemfibrozil and fenofibrate.
  • HMG CoA reductase inhibitors (also called statin drugs) block the action of an enzyme (HMG CoA reductase) in the liver, thereby significantly decreasing production of cholesterol in the liver. Possible side effects include occasional muscle aches and nausea. Very rarely, liver damage may occur. Examples of statin drugs include atorvastatin and simvastatin.
  • Niacin (nicotinic acid) is a vitamin that decreases production of LDL cholesterol in the liver. Depending on the dosage, it also can increase HDL cholesterol levels. Possible side effects include bloating, cramping, and diarrhea. Very rarely, niacin may damage the liver. A variety of nonprescription versions of niacin are available over-the-counter.
  • Probucol decreases blood levels of LDL cholesterol but also can decrease blood levels of HDL cholesterol. Diarrhea is the most common side effect of this medication.

You will need to watch for possible side effects while taking certain cholesterol-lowering medications and report them to your physician. Your doctor may ask you to try to live with some side effects for a few weeks to see if your body adjusts to it. Also, your doctor will carefully monitor your cholesterol levels and liver function regularly through blood tests.

Heart, Blood, and Circulation

Common

Health

Concerns

Surgical Procedures for Heart Disease Atherosclerosis and the resulting coronary artery disease are progressive. This means that once these problems develop, they will continue to worsen until they are successfully treated. When lifestyle changes or medication cannot control the progression of the disease, surgery may be necessary. Possible procedures performed to treat this condition include coronary artery bypass surgery, coronary angioplasty, and placement of a stent.

Coronary artery bypass surgery, commonly called bypass surgery, is highly effective for people who have angina and whose coronary artery disease is not widespread. Bypass surgery is the procedure most widely used to treat coronary artery disease due to atherosclerosis. It can improve exercise tolerance, reduce symptoms, and decrease the amount of medication needed. Bypass surgery is most likely to benefit people who have severe angina that cannot be controlled with medication, a normally functioning heart, and no previous heart attacks. About 85 percent of patients who undergo bypass surgery experience complete or significant relief of symptoms.

The procedure involves grafting (transplanting healthy tissue from one part of the body to another) veins or arteries onto the coronary artery to receive blood flow, thereby "bypassing" the obstructed area. Usually the bypass veins are taken from the leg. Most surgeons also use at least one artery as a graft. The bypass artery usually is taken from beneath the chest wall. These arteries rarely develop atherosclerosis, and more than 90 percent of them remain open and work properly 10 years after the bypass surgery. Vein grafts may become obstructed and, after 5 years, a third or more of them may be completely blocked. In such cases the procedure may need to be repeated.

Coronary angioplasty, also called balloon angioplasty, is performed to open a narrowed or blocked coronary artery. The procedure begins with insertion of a hollow needle into the femoral artery in the leg. A long guide wire is threaded

Blockage v

Bypass — Right coronary artery

Coronary Artery Bypass

In this example, two bypasses using replacement blood vessels from other parts of the body have been created to reroute blood around blockages in the right and left coronary arteries.

Bypass

Blockage v

Bypass — Right coronary artery

Coronary Artery Bypass

In this example, two bypasses using replacement blood vessels from other parts of the body have been created to reroute blood around blockages in the right and left coronary arteries.

Left anterior descending artery

Bypass

Blockage

Left coronary artery

Left anterior descending artery through the needle and into the arterial system, through the aorta, and into the obstructed coronary artery. A catheter (a thin, flexible tube) with a balloon attached to its tip is threaded over the guide wire and into the obstructed artery. The catheter is positioned so the balloon is at the level of the obstruction. The balloon is then inflated and deflated several times, for several seconds each time. The inflated balloon compresses the plaque against the artery wall, widening the narrowed channel and restoring blood flow. The catheter and guide wire are then withdrawn.

Between 80 and 90 percent of arteries that are treated with angioplasty are opened. In about 20 to 30 percent of cases, the coronary artery becomes obstructed again (called restenosis) within 6 months, often within a few weeks after the procedure. Angioplasty is then repeated. This procedure may be used to successfully control coronary artery disease over the long term.

Stent placement is a newer procedure that has been performed more frequently in the past several years. Essentially it is angioplasty, with an additional step. Once the obstructed artery has been opened, a tiny metallic or plastic wire mesh (stent) is placed inside the artery to keep it open. This procedure may reduce the risk of restenosis by half.

Numerous studies have shown that success rates of angioplasty are about the same as those of bypass surgery. Most studies comparing these two procedures are now focusing on economics. Recent studies give the edge to bypass surgery in terms of the cost of treating patients over the long term.

Weight Loss Funnel

Weight Loss Funnel

Who Else Wants To Discover The 3 Most Effective Fat Burning Methods The Weight Loss Industry Does NOT Want You To Know About.

Get My Free Ebook


Post a comment