All of the organs and tissues in the body need a blood supply in order to function, because blood carries oxygen and sources of energy. It is the heart's job to pump oxygen-rich blood through the huge network of arteries that extend throughout the body, including pumping blood into vessels that supply the heart muscle itself. These vessels, called coronary arteries, lie on the outside of the heart muscle.

Coronary Artery Disease (CAD) or Ischemic Heart Disease (IHD) is a condition affecting these arteries that run on the surface of the heart and supply blood to the heart muscles. The most common cause of CAD is atherosclerosis, where fatty deposits including cholesterol and other fats, calcium and certain other elements carried in the blood build up as a plaque on the inside of artery walls. This tends to reduce the flow through the arteries and therefore, less oxygen and other nutrients reach the heart muscle. This can lead to problems ranging from pain in the chest to heart attack, heart failure, or rhythm abnormalities and sudden cardiac death. The chest pain (angina pectoris), or a heart attack (myocardial infarction) are manifestation of the same disease, the difference being that of severity. If it affects the arteries supplying the brain, a stroke (paralysis attack) may result.

Angina usually occurs when the heart has to work harder than usual, as during exercise or emotion. There is pressure, tightness or pain in chest, arm, neck, back or jaw. The part of the heart muscle normally supplied with oxygen by the narrowed artery cannot get enough blood. With rest or medicines like Sorbitrate or Isordil, the heart's demand for blood is met temporarily and so pain disappears. There is no permanent damage to the heart. With a heart attack, a narrowed artery is suddenly blocked completely by a clot forming at the point of narrowing. The part of the heart muscle supplied by that artery does not receive any oxygen and begins to die. This can damage the heart's ability to pump blood and causes chest pain, which does not disappear with rest. Symptoms of a heart attack may also include shortness of breath, sweating, weakness or dizziness.

Angina usually occurs when the heart has to work harder than usual, as during exercise or emotion. There is pressure, tightness or pain in chest, arm, neck, back or jaw. The part of the heart muscle normally supplied with oxygen by the narrowed artery cannot get enough blood. With rest or special tablets (Sorbitrate or Isordil), the heart's demand for blood goes back to normal and pain goes away. There is no permanent damage to the heart.

With a heart attack, a narrowed artery is suddenly blocked completely by a clot forming at the point of narrowing. The part of the heart muscle supplied by that artery does not receive any oxygen and begins to die. This can damage the heart's ability to pump blood and causes chest pain, which does not disappear with rest. Symptoms of a heart attack may also include shortness of breath, sweating, weakness or dizziness.

Current understanding of the this disease process, though somewhat complex, is as follows:

• A number of environmental or physical factors are involved in triggering excess amounts of unstable particles known as oxygen-free radicals , which bind with and alter other molecules, a process called oxidation. (The particles are released as part of normal bodily processes, but environmental toxins, such as smoking, can produce excess amounts.)
• When free radicals are released in artery linings, they react with and oxidize low-density lipoproteins (LDL). (Lipoproteins are sphere-shaped bodies that carry cholesterol, and LDL is the well-known villain referred to as the "bad cholesterol.")
• LDL deposits mushy layers of oxidized cholesterol on the walls of the artery.
• The cholesterol accumulates.
• The injuries to the arteries during this process signal the immune system to release white blood cells (particularly those called neutrophils and macrophages) at the site. This initiates an important and damaging process called the inflammatory response.
• Macrophages literally "eat" foreign debris, in this case oxidized cholesterol, and become foamy cells that attach to smooth muscle cells causing them to build up.
• Over time the cholesterol hardens and forms plaque, which builds up on the walls of the arteries.
• The immune system, sensing further harm, releases other factors called cytokines, which attract more white blood cells and perpetuate the whole cycle, causing persistent injury to the arteries.
• Injured inner vessel walls fail to produce enough nitric oxide , a substance critical for maintaining blood vessel elasticity.
• Eventually these calcified (hardened) and inelastic arteries become narrower (a condition known as stenosis). As this process continues, blood flow slows and prevents sufficient oxygen-rich blood from reaching the heart.
• Such oxygen deprivation in vital cells is called ischemia. When it affects the coronary arteries, it causes injury to the tissues of the heart.
• Heart attack can occur as a result of one or two effects of atherosclerosis:
  1. If the artery becomes completely blocked and ischemia becomes so extensive that oxygen-bearing tissues around the heart die.
  2. If the plaque itself develops fissures or tears. Blood platelets adhere to the site to seal off the plaque and a blood clot (thrombus) forms. A heart attack can then occur if the blood clot formed completely blocks the passage of oxygen-rich blood to the heart.

Types of Angina:

Stable Angina
Stable angina is predictable chest pain. Although less serious than unstable angina, it can be extremely painful. It is usually relieved by rest and responds well to medical treatment (typically nitroglycerin). Any event that increases oxygen demand can cause an angina attack. Some typical triggers include the following:

• exercise,
• cold weather,
• emotional tension, or
• large meals.

Angina attacks can occur at any time during the day, but a high proportion seems to take place between the hours of 4:00 AM and noon.

Unstable Angina
Unstable angina is a much more serious situation and is often an intermediate stage between stable angina and a heart attack. A patient is usually diagnosed with unstable angina under one or more of the following conditions:

• Pain awakens a patient or occurs during rest.
• A patient who has never experienced angina has severe or moderate pain during mild exertion (walking two level blocks or climbing one flight of stairs).
• Stable angina has progressed in severity and frequency within a two-month period, and medications are less effective in relieving its pain.

Prinzmetal's Angina
A third type of angina, called variant or Prinzmetal's angina, is caused by a spasm of a coronary artery. It almost always occurs when the patient is at rest. Irregular heartbeats are common, but the pain is generally relieved immediately with treatment.

Silent Ischemia
Some people with severe coronary artery disease do not experience angina pain, a condition known as silent ischemia , which some experts attribute to abnormal processing of heart pain by the brain. Diabetics also may not report pain. This is a dangerous condition because patients have no warning signs of heart disease.

RISK FACTORS

Risk factors are not necessarily an inevitable result of aging but are primarily related to lifestyle and environmental factors. The good news is that many if not all can be modified with a combination of a low-fat diet, weight loss, exercise, and medications. Over the past decades, heart disease declined in both men and women as they quit smoking, improved dietary habits and took to regular exercise.

Reducing Multiple Risk Factors
The risk for heart disease increases with multiple risk factors, importantly unhealthy cholesterol or lipid levels, obesity, smoking, and hypertension. (For example, a cluster of risk factors called syndrome X poses a particularly high risk for heart and other diseases. It consists of having high blood sugar, high blood pressure, low HDL cholesterol, and high triglycerides. The syndrome, which occurs in about 3% of men and 3.4% of women, appears to be due to abnormalities in the small arteries.)

Conversely, risk plummets in the absence of multiple risk factors. For example, in a 1999 study of men and women of all ages, nonsmoking, nondiabetics who had low cholesterol levels (less than 200 mg/ml) and low blood pressure (less than 120/80) had a risk of dying from heart attack that was between 77% and 92% lower than those with risk factors. (They also had a lower risk for stroke and cancer.) Similarly, a 2000 study reported that patients who aggressively pursued a healthy lifestyle (low-fat diet, stress management, smoking cessation, moderate aerobic exercise) significantly reduced their risk for heart attack, cardiac surgery, and death.

Gender
Coronary artery disease is much more common in middle-aged men. Women have, on average, ten to fifteen more years of heart-disease free life than do men, but as women age, they catch up to men. Women, in fact, are more likely to have angina than men are. When adjusted for age, survival rates from heart attacks are similar in older men and women, but younger women are at greater risk for death from heart attack than men their own age.

The reasons for this are not clear. Estrogen, which appears to be heart protective, may play a role, and it may be that many younger women who have heart attacks have lower estrogen levels. For example, in a 2000 study, women who entered natural menopause early (age 35-40), had a higher risk for death from heart attack than did women who entered menopause later.

Many studies have reported that women are less aggressively treated than men for all phases of heart disease. More recent ones have suggested, however, that women and men are treated similarly during late stages of heart disease (such as during a heart attack), but not when they first come to the hospital with heart disease. Younger women with heart disease often do not have the same symptoms as their male counterparts and are less likely to be diagnosed correctly or aggressively. In fact, women's symptoms are less likely to appear as typical angina, and women are more often tested for gastrointestinal problems than men. (Interestingly, one 1999 study found that although, indeed, women with unstable angina were treated less aggressively than men, when their risk factors were compared head to head, men actually had a worse long-term outcome.)

Ethnicity
Indians seem to be particularly vulnerable to the CAD, the incidence of disease is rising at an alarming rate, is striking younger population and is more diffuse, compared to their western counterparts. And all of it is not just because Indians as a community are physically less active, but partly may be due to genetic predisposition.

Smoking
Smokers in their thirties and forties have a heart-attack rate that is five times higher than their nonsmoking peers. Cigarette smoking may be directly responsible for at least 20% of all deaths from heart disease, or about 120,000 deaths annually. Smoking cigars may increase the risk of early death from heart disease, although evidence is much stronger for cigarette smoking.

Its damaging effects on the heart are multifold:

• Smoking lowers HDL levels (the so-called good cholesterol) even in adolescents.
• It causes deterioration of elastic properties in the aorta, the largest blood vessel in the body, and increases the risk for blood clots.
• It increases the activity of the sympathetic nervous system (which regulates the heart and blood vessels).
• Tobacco smoke may increase cardiovascular disease in women through an effect on hormones that causes estrogen deficiency

Cholesterol and Other Lipids
A number of studies have now demonstrated that reducing LDL and total cholesterol levels and boosting HDL levels have improved survival and prevented heart attacks. Depending on risk factors, people should aim for the following cholesterol levels:

General cholesterol targets:

• Total cholesterol levels: 200 mg/dl or below.
• LDL cholesterol levels: 160 mg/dl or below. (The lower the better.)
• HDL cholesterol levels: 45 mg/dL for men and 50 mg/dL for women, with everyone aiming for about 60. (The higher the better.)
• Triglyceride levels: 200 mg/dL or lower. (Although some evidence suggests that people should aim for levels under 100 mg/dL to reduce the risk for heart disease.)

Targets for people with two or more risk factors for heart disease:
  LDL levels: 130 mg/dl or below.

Targets for people with existing heart disease:
  LDL levels of below 100 mg/dl.

Elevated levels of other lipids, including lipoprotein (a) and apolipoprotein A-1 and B are also now thought to be important indicators of heart risk. Apolipoprotein B, for example, may actually turn out to be a very accurate indicator of heart disease risk in women

High Blood Pressure
High blood pressure, or hypertension, has long been a proven cause of coronary artery disease. Blood pressure is categorized as:

• Optimal (below 120/80 mm Hg).
• Normal (between 120/80 and 130/85 mm Hg).
• High normal (between 130/85 and 139/89). (Some studies indicate that high normal puts one at higher risk for heart events and stroke, although others suggest this risk exists primarily in people with diabetes.)
• Hypertension, or high blood pressure (140/90).

A number of studies have now reported that an elevated systolic blood pressure is a significantly more accurate indicator of hypertension, particularly in the elderly. (The systolic pressure is the higher and first number in blood pressure measurements. It measures the force that blood exerts on the artery walls as the heart contracts to pump out the blood.) In addition, the difference between the two numbers, which is called the pulse pressure, appears to be associated with an increased risk for CHD. Higher pulse pressures are associated with an enhanced risk for CHD.

Sedentary Lifestyle and Exercise
People who are sedentary are almost twice as likely to suffer heart attacks as are people who exercise regularly. Regular moderate aerobic exercise benefits the heart in many ways. For instance, brisk walking has the following advantages:

• lowers the heart rate and blood pressure
• improves cholesterol
• lowers blood sugar levels
• opens up the blood vessels and, in combination with a healthy diet, may improve blood clotting factors
• reduces stress and improves mood

Some studies suggest that for the greatest heart protection, it is not the duration of the exercise that counts but the total daily amount of energy expended. Therefore, the best way to exercise may be in multiple short bouts of intense exercise. Even elderly people with unstable angina or who had a previous heart attack can benefit from a structured exercise program, but do check up with your doctor, he knows what is best for you. Exercises that train and strengthen the chest muscles may also prove to be very important for patients with angina.

It should be noted that sudden strenuous exercise (such as snow shoveling and mowing lawns) puts such people at risk for angina and heart attack. Activities that involve raising the arms above the head may also be risky. Patients with angina should never exercise shortly after eating.

People with risk factors for heart disease should seek medical clearance and a detailed exercise prescription. And all people, including healthy individuals, should listen carefully to their bodies for signs of distress as they exercise.

Long-term insulin resistance, even without type 2 diabetes, appears to have significant damaging effects on the heart. This condition occurs when insulin levels are normal to high but the body is unable to use the insulin to regulate metabolism of blood sugar and to store it for energy. In such cases, the body compensates by increasing insulin levels (hyperinsulinemia), which in turn increases triglyceride levels and reduces HDL cholesterol. Normally, insulin stimulates the release of two substances, endothelin and nitric oxide, that are important in keeping arteries elastic and open. Insulin resistance may cause an imbalance in these substances.

Homocysteine
Abnormally high blood levels of the amino acid homocysteine are strongly linked to an increased risk of coronary artery disease and stroke. Homocysteine may harm the lining of the arteries and contribute to blood clotting. Excessive levels occur with deficiencies of vitamins B6, B12, and folic acid. Some experts believe that high levels of homocysteine are only indicators, not causes, of heart disease. However, studies are reporting strong associations between this factor and heart disease.

Obesity
Obesity is related to hypertension, diabetes, abnormal cholesterol levels, and lack of exercise, all conditions contributing to heart attack risk. Abdominal obesity (the "beer belly") poses a particular risk. In fact, a 2000 study reported that men who have waists that measure more than 36 inches and high triglyceride levels (more than 2 mmol/L) are at high risk for developing heart disease within five years. Obesity in children is a greater risk for future heart trouble than a family history of heart disease. People who are overweight in middle age may still not completely reduce their risk for coronary artery disease later in life, even if they lose excess weight.

Eating Habits
Fats. Experts now believe that fats can have both harmful and beneficial effects. (Whether harmful or beneficial they are still high in calories):

Harmful fats: Everyone should limit and try to avoid the following fats:

• Saturated fats, predominantly in animal products, including meat and dairy products. (The so-called tropical oils, palm, coconut, and cocoa butter, are also high in saturated fats. Evidence is lacking, however, about their effects on the heart.)
  Trans-fatty acids, which are created during a process aimed at stabilizing polyunsaturated oils to prevent them from becoming rancid and to keep them solid at room temperature. Hydrogenated fats are used in stick margarine and in many fast foods and baked goods. (Liquid margarine is not hydrogenated.)

Beneficial oils: Public attention has mainly focused on the possible benefits of monounsaturated and polyunsaturated fats found in vegetables oils. Researchers are most interested, however, in the smaller fatty-acid building blocks contained in these oils called essential fatty acids. Studies indicate that in a healthy balance, all of these fatty acids are essential to life:

• Omega-3 fatty acids: further categorized as:
  Alpha-linolenic acid (sources include canola oil, soybeans, flaxseed, olive oil, and many nuts and seeds). Indications that it is heart protective. (Extra virgin olive oil in one study was associated with lower blood pressure. Many studies have singled out nuts, which contain omega-3 fatty acids, fiber, as being particularly beneficial for the heart by lowering LDL and total cholesterol without increasing triglycerides.) and
  
  Docosahexaenoic and eicosapentaneoic acids (sources are oily fish). May not have much effect on cholesterol but they may benefit the lining of blood vessel (the endothelium) and therefore improve blood flow.
• Omega-6 fatty acids: further categorized as linoleic, or linolic, acid (sources are flaxseed, corn, soybean, and canola oil).
• Omega-9 fatty acids: (Source is olive oil).

Some experts recommend maintaining a relatively high intake of monounsaturated and polyunsaturated fats (about 32% of calorie intake), with saturated fats representing no more than 8%. Others believe that a very trim diet, 20% fat with as little as 4% saturated fat, is ideal. Still others recommend fat intake somewhere in between these extremes.

Carbohydrates. Meals overly rich in carbohydrates tend to set off angina attacks, possibly because they raise insulin levels. One study suggested, in fact, that in women, sugar may pose an even higher risk for heart disease than fats do. Whole grains and fresh fruits and vegetables (particularly dark-colored ones), however, are very important. They are rich in fiber, vitamins, and other important nutrients that are heart-protective. Natural chemicals in cooked tomatoes, garlic, nuts, apples, onions, wine, and tea also appear to offer protection for the heart.

Protein. Soy is proving to be a particularly excellent source of protein. It is rich in both soluble and insoluble fiber, omega-3 fatty acids, and provides all essential proteins. It has estrogen-like compounds that might be as effective as estrogen therapy itself in slowing progression of heart disease without increasing triglycerides or the risk for breast cancer (as estrogen therapy does).

Much evidence suggests that eating fish two or three times a week, particularly oily fish (such as salmon, halibut, swordfish, and tuna) is protective.

Salt. Studies now indicate that sodium intake may be a major contributor to heart disease in overweight people. Its effect on people with normal or low weight may not be as severe, although everyone would do well to keep salt intake to a minimum.

Vitamins and Supplements
B Vitamins. Sufficient amounts of folic acid, B6, and B12 are certainly important to prevent high levels of homocysteine.

Vitamin E. A number of small studies have found an association between a lower risk for coronary artery disease with doses of vitamin E between 100 and 400 IU. One important 2000 study, however, reported that taking vitamin E in daily doses of 400 IU for over four years had no benefits for people at high risk for heart attack or other heart events. It should also be noted that in people taking medications to prevent clotting, such as aspirin or heparin, adding vitamin E could theoretically increase the risk for bleeding.

Vitamin C. Little evidence has emerged to prove any protective effects from taking vitamin C. Of interest, however, is a study suggesting that long term administration of vitamin C may improve endothelial function, a factor affecting blood flow.

Beta Carotene. Studies have reported that a high intake of beta-carotene and other carotenoids from dark colored fruits and vegetables (but not from supplements) may reduce the risk of heart attack. (Smokers who take beta carotene supplements may face a higher risk for lung cancer.)

Note: Studies are continuing to indicate that high doses of antioxidants supplements, such as vitamins C, E, and beta carotene, may have pro-oxidant effects that can harm the arteries and incur other damage.

Psychological Factors
Stress. Mental stress is as important a trigger for angina as physical stress. Incidents of acute stress have been associated with a higher risk for serious cardiac events, such as heart rhythm abnormalities and heart attacks, and even death from such events in people with heart disease. Stress may negatively affect the heart in several ways:

• Sudden stress increases the pumping action and rate of the heart and causes the arteries to constrict, thereby posing a risk for blocking blood flow to the heart.
• Emotional effects of stress alter heart rhythms and pose a risk for serious arrhythmias in people with existing heart rhythm disturbances.
• Stress causes blood to become stickier (possibly in preparation of potential injury), increasing the likelihood of an artery-clogging blood clot.
• Stress may signal the body to release fat into the bloodstream, raising blood-cholesterol levels, at least temporarily.
• Stress may lead to increased levels of homocysteine.
• In women, chronic stress may reduce estrogen levels.
• Stressful events may cause men and women who have relatively low levels of the neurotransmitter serotonin (and thus a higher risk for depression or anger) to produce more of certain immune system proteins (called cytokines), which in high amounts cause inflammation and damage to cells.
• Stress causes a sudden and temporary increase in blood pressure, although long-term effects are not completely known. [ See Stress.]

Depression. Studies indicate that depression may have adverse biologic effects on the immune system, blood clotting, blood pressure, blood vessels, and heart rhythms. Depression may even impair a patient's response to medication for heart disease. In one 30-year study, men who were clinically depressed had a greater risk for heart disease and heart attack than men who were not depressed; this increased risk lasted for decades. The more severe the depression, the more dangerous to the health, although some studies have indicated that even mild depression, including feelings of hopelessness, experienced over many years, may harm the hearts in people with no early signs of heart disease . [ See Depression.]

Alcohol
The effects of alcohol on heart disease vary depending on consumption. Evidence strongly suggests that light to moderate alcohol consumption (one or two drinks a day) protects the heart. The benefits are strongest in people at high risk for heart disease and may be fairly small in those at low risk. Light to moderate alcohol intake may even reduce the risk of sudden cardiac death and also protect against coronary heart disease in people with adult-onset diabetes. Large amounts of alcohol, however, can raise blood pressure, trigger irregular heartbeats, and damage the heart muscle. Binge drinkers have a significantly higher risk for a cardiac emergency.

Estrogen
Benefits of Estrogen. Estrogen appears to have many benefits for the heart:

• It protects against unhealthy cholesterol, triglyceride, and other lipid levels.
• It may have direct actions on blood vessels, relaxing, and opening them and keeping their lining smooth.
• Estrogen is also an antioxidant. It helps neutralize oxygen free radicals.
• The effects of estrogen on blood pressure are not clear; oral contraceptives, for instance, appear to increase pressure slightly. Two 1999 studies reported, however, that supplementary estrogen reduced night-time blood pressure in women with normal pressure.
• Estrogen also affects many blood clotting factors in the liver; it reduces blood viscosity (stickiness) and may enhance fibrinolysis, the natural process for breaking down blood clots. (Estrogen's effects on clotting, however, are complex, since there is also a well-known increased risk for thromboembolism (blood clots that blocks a vessel) in women taking estrogen.

Hormone Replacement Therapy. After menopause, estrogen levels decline dramatically. Hormone replacement therapy for postmenopausal women is problematic, however. A number of studies have reported that unopposed estrogen helps prevent heart disease from developing in the first place. Neither unopposed estrogen therapy nor estrogen combined with progestins, however, appears to stop progression of heart disease in women who already have evidence of it. In fact, studies have also reported that the risk for heart attack and stroke is slightly higher in the first two years of treatment. The risk declines afterward, however, and in one study by the fourth and fifth year, HRT-users had fewer heart events. The reasons for the higher risk may be due to estrogen's actions on increasing the risk for blood clots and possible pro-inflammatory effects in certain women.

Genetic Factors
Genetics are involved in increasing the likelihood of developing important risk factors (eg, diabetes, obesity, and high blood pressure). One genetic variant called apolipoprotein E4 (ApoE4) affects cholesterol levels, particularly those associated with heart disease. A 1999 study suggests that it may be a significant risk factor for coronary artery disease in early middle age. (This variant also increases the risk for Alzheimer's disease.)

Infectious Agents
Some microorganisms and viruses have been under suspicion for triggering inflammation in the arteries and contributing to heart disease risk. The primary suspects have been Chlamydia pneumoniae (a non-bacterial organism that causes mild pneumonia in young adults), H. pylori (bacteria responsible for peptic ulcers), and the viruses herpesvirus and cytomegalovirus. Animal studies have reported strong associations between some of these microorganisms and future heart disease, but recent studies have suggested that any causal role in people is likely to be weak. Nevertheless, research does suggest that inflammation after infection may injure the cells lining blood vessels. And, in a 1999 study, researchers did report that patients who had high levels of a byproduct of bacterial infection called endotoxin had three times the normal risk for heart disease. This study still does not prove that bacteria actually cause heart disease.

Fibrinogen
Fibrinogen, a plasma protein, is important to the blood's ability to form clots. However, high levels have been shown to be associated with CHD. It is unknown if fibrinogen levels are modifiable.

Markers of inflammation
Markers of inflammation, particularly blood levels of C reactive protein, are important predictors for cardiovascular disease in men and women. It has been suggested that measurement of C reactive protein should be added to standard lipid screening to improve global risk prediction in those with high as well as low cholesterol. Measurement of C reactive protein levels is rapidly being integrated into practice.

Other Factors
Factors before Birth and In Infancy. Low weight at birth and in the womb has been associated with later heart disease in a few studies. Some suggest, however, that this may just reflect poor nutrition in the mother, which appears to affect life-long risk. A 2000 British study reinforced the idea that pre-birth or other early events have little significant effect on heart disease risk in later life.

Seasonal Differences. More deaths from heart disease occur in December and January and fewest in the summertime. Although lower temperatures and snow shoveling may play a role in some cases, more winter deaths have been reported even in warm regions. Holiday stress or fewer daylight hours have been suggested as other reasons for these higher winter rates.

Iron. High dietary intake of iron may be an important factor in the process of atherosclerosis.

Physical Characteristics. Male pattern baldness, hair in the ear canals, and creased earlobes are associated with a higher risk for heart disease in white males. (Interestingly, in African American men, of these factors, only creased earlobes were associated with a higher risk in one study.)

Snoring and Sleep Apnea. A 2000 study reported a modest increase in heart disease in women who snore regularly, regardless of whether they were overweight or had other heart risk factors. Snoring is a common symptom of obstructive sleep apnea. In this condition, tissues in the upper throat collapse at intervals during sleep, thereby blocking the passage of air. Sleep apnea is a known risk factor for high blood pressure and is highly associated with obesity. But it may contribute to heart disease through other actions as well. For example, during the night, apnea has been associated with a higher incidence of ischemia (reduced supply of oxygen rich blood) and in the morning with "stickier" blood (increasing the risk for blood clots).

Diagnosis of CAD

Blood and Urine Tests
Blood and urine tests that indicate a risk for coronary artery disease and heart attack include those for cholesterol, homocysteine, the protein albumin, and blood clotting factors, especially fibrinogen. When heart cells become damaged, they release different enzymes and other molecules into the blood stream. Elevated levels of such markers of heart damage in the blood or urine may help predict a heart attack in patients with severe chest pain. Some of these factors include the following:

• Troponins. The enzymes cardiac troponin T and I are released when the heart muscle is damaged. Both are proving to be among the best markers for a high risk for heart attacks in patients with non-elevated ST segments.
• Creatine kinase myocardial band (CK-MB). CK-MB has been a standard marker but it is not very accurate since elevated levels can appear in people without heart injury. Certain forms of CK-MB may improve its ability to specifically target heart injury.
• Myoglobin. Myoglobin is a protein found in heart muscles. It is released early in the injured heart and it may be useful in combination with CK-MB and the tropinins.
• Fibrinogen is a protein involved in blood clotting.
• C-reactive protein is a product of the inflammatory process. Markers that show a very strong inflammatory response in patients with unstable angina may be important indicators for aggressive treatment.
  

Electrocardiograms
The electrocardiogram (ECG) measures the wave patterns of the heart. It is the critical first diagnostic step and when a heart attack is suspected, a patient is monitored continuously with an ECG. It is used to both determine the severity of the condition and the optimal immediate treatment. It is also extremely important to rule out other dangerous conditions. The most important wave patterns in diagnosing and determining treatment for a heart attack are called ST elevations and Q waves .

Elevated ST-segments indicate that the artery to an area of the heart is blocked, and that the full thickness of the heart muscle is damaged. In most cases patients go on to develop a full-blown heart attack, medically referred to as a Q-wave myocardial infarction. ST-elevations are good indicators for aggressive treatments (thrombolytic drugs or angioplasty) to reopen blood vessels. In a some cases, however, the patient's status drops to a non-Q-wave myocardial infarction, a less serious condition.

Non-elevated ST segments indicate a normal heart beat and occur in about half of patients with other signs of a heart event. In such cases, laboratory tests are needed to determine the extent, if any, of heart damage. In general, one of three following conditions may be present:

• Angina (blood test results or other tests show no serious problems and chest pain resolves). Most patients with angina can go home.
• Unstable angina (blood tests do not show markers for heart attack but chest pain is persistent). Unstable angina is potentially serious.
• Non Q-wave myocardial infarction (blood tests suggest a developing heart attack but most likely injury in the arteries is less serious than with a full-blown heart attack).

Depressed ST-segments represent a potentially very serious problem.

Echocardiograms
An echocardiogram uses ultrasound images of the heart. This test is more expensive than an ECG, but it can detect muscle weakness from a prior heart attack or motion abnormalities. Echocardiograms may be more useful for women than ECGs.

Stress Test
Basic Procedure. A stress test (exercise tolerance test) monitors the patient's heart rhythms, blood pressure, and clinical status. Because stress tests can precipitate angina, irregular heart rhythms, or, rarely, even heart attacks, they must be performed under careful supervision. A typical stress test involves the following:

• The patient walks on a treadmill or rides a stationary bicycle. (For patients who cannot exercise, the drug dobutamine may be given, which simulates the stress of exercise.)
• Exercise continues until the heart is beating at least 85% of its maximum rate or until heart rhythm abnormalities, angina, fatigue, or other symptoms of heart trouble occur.
• An ECG is usually used to monitor heart rhythms during a stress test, although an echocardiogram may be used.
• Failure to reach the target heart rate may be a sign of a risk for heart attack and angina in people with coronary artery disease or even a predictor for coronary artery disease in people without a current problem.

Unfortunately, only about 65% of patients are diagnosed correctly using an ECG with the test, and the accuracy is even worse for women. (Using an echocardiogram instead of an ECG may be a more accurate procedure for women.) About 10% of healthy patients, particularly younger people, will have abnormal test results (false positive).

Stress-Thallium Test. The stress-thallium test may be used with the exercise stress test. It is a reliable measure of severe heart events:

• Before starting to exercise, the patient receives an injection of thallium 201, a radioactive chemical, which is taken up by normal heart muscle cells.
• Immediately after exercise, heart scans are performed.
• If muscle tissue is damaged by ischemia (oxygen deprivation), it will fail to take up thallium and will be detected on the scanned image.
• If the scan detects damage, it is repeated two or three hours after exercise.
• Damage due to a prior heart attack will persist when the heart scan is repeated. Injury caused by angina, however, will have resolved by that time.

Electron Beam Computed Tomography
Electron beam computed tomography (EBCT) scans (also called ultrafast computed tomography (CT) scans) are so fast that they can freeze the motion of the heart. Scans from EBCT reveal deposits of calcium on the arterial walls, indicators of current and future coronary artery disease. This is the only technique that can detect coronary artery disease in all stages of development from asymptomatic heart disease to conditions severe enough to produce heart attacks. The test is expensive, however, and there is much controversy over whether EBCT should be used as a widespread screening tool to detect early coronary artery disease.

Angiography
Angiography is an invasive test that may be performed on patients who have very incapacitating angina that does not respond to medical therapy:

• A narrow tube is inserted into an artery, usually in the leg or arm, and then threaded up through the body to the coronary arteries.
• A dye is injected into the tube and an x-ray records the flow of dye through the arteries.
• This process provides a map of the coronary circulation, revealing any blocked areas.

Of some importance is a study reporting that women with chest pain may have a normal angiogram but still have evidence of heart disease from tests. Major complications include stroke, heart attacks, and kidney damage. These risks are very low (about 0.1%), however, if the procedure is done in an experienced medical center (one that performs at least 300 of these operations every year). Allergic reactions can also occur. The procedure is expensive, and between 10% to 30% of patients who have this procedure have normal results.

Magnetic Resonance Imaging
Enhanced software for magnetic resonance imaging (MRI) techniques, which are nonradioactive, are providing accurate information on arterial blood flow, including that in very small vessels not visible using angiography.

A. Aspirin and antianginal drugs

B. Blood pressure and beta-blockers

C. Cholesterol and cigarettes;

D. Diet and diabetes;

E. Exercise and education.

What is angioplasty or PTCA?

Percutaneous transluminal coronary angioplasty (PTCA), usually simply called angioplasty, involved opening the blocked artery. A typical angioplasty procedure involves the following steps: (also see animation)

• The cardiologist threads a narrow catheter (a tube) containing a fiber optic camera directly to the blocked vessel.
• The physician opens the blocked vessel using balloon angioplasty , in which the cardiologist passes a tiny deflated balloon through the catheter to the vessel.
• The balloon is inflated to compress the plaque against the walls of the artery, flattening it out so that blood can once again flow through the blood vessel freely.
• In order to keep the artery open afterwards, cardiologists now commonly employ a device called a coronary stent , which is an expandable metal mesh or scaffolding tube that is implanted during angioplasty at the site of the blockage.
• Once in place, the stent pushes against the wall of the artery to keep it open. (A number of studies are reporting fewer future heart attacks and restenosis in patients who receive stents compared with those who had angioplasty alone.)

Stenting is now used in about 60%, at EHIRC the figure is touching 90%, of angioplasty procedures. Studies report high survival rates with the use of stents, including their use with multiple blood vessels and as the initial device after a heart attack instead of balloon angioplasty. Some experts now recommend they be used only to prevent restenosis in patients with large blood vessels (greater than 3 mm).

Recuperation. Angioplasty is less invasive than bypass surgery, requiring only one night in the hospital. Recuperation takes about a week. It should be pointed out the chest pain after the procedure is very common and usually due to problems other than ischemia. Chest pain is even more common when a stent is used, possibly because the artery is stretched.

Short-Term Complications: Reclosure During or Shortly after Angioplasty. Reclosure of the artery during or shortly after angioplasty is often but not always due to blood clots. Aspirin, heparin, coumarin, or combinations of anti-clotting drugs are generally used during and after the operation. Aspirin is more effective than heparin. New anti-clotting agents (tirofiban, abciximab, argatroban, clopidogrel, or bivalirudin) may be more effective for preventing reclosure, often when administered in combination with heparin or aspirin. Anti-clotting drugs are not wholly protective, in any case, because reclosure in some cases is due to other, unknown causes.

Long-Term Complications: Reclosure (Restenosis) Within a Year of Angioplasty. Narrowing or reclosing of the artery (restenosis) occurs within a year of angioplasty in nearly half of angioplasty patients, often requiring a repeat operation. Reclosure, in this case is not due to blood clots and so anti-clotting agents are not useful. Theories for the cause of restenosis include the following:

• The release of large amounts of oxidants (damaging unstable particles) at the surgical site may activate damage in certain white blood cells that causes overgrowth in smooth muscles in the blood vessels. With this theory in mind, researchers have tested an antioxidant drug, probucol (Lorelco), with some success. Other drugs that are being investigated for their ability to limit smooth muscle growth include verapamil, a calcium channel blocker, and a protein called angiopeptin.
• Some experts argue that other activities, such as scarring, may remodel and narrow the blood vessels.

A number of approaches, including coronary stents, have been developed to prevent restenosis.

• Radiation treatment of the site is used to prevent reclosure, although some experts are concerned about its long-term safety. Studies suggest, however, a high rate of late blockage occurring after angioplasty within two to 15 months in patients who receive radiation treatments.
• Directional atherectomy has been another attempt to solve the problem of reocclusion of the blood vessels. A balloon catheter is inserted for determining position; then, a tiny cutter spinning at 2,500 rpm removes plaque fragments from the arterial walls. The use of angioplasty with the coronary artery stent, however, is proving to be safer and more effective.

The result of this procedure is that the blood vessel is dilated, and blood can flow more easily through the (formerly narrowed) part of the coronary artery. It is used mostly to relieve angina, but is sometimes used as an emergency procedure to improve blood flow during a heart attack, (Primary angioplasty).

Sometimes the plaque is also removed through atherectomy in which a catheter with a coarse burr (rotablator) at the tip is used to grind the plaque into small bits. These bits float away in the blood stream.

After Angioplasty or atherectomy, a stent may be placed in the artery to improve upon the result (nowadays about 90% of patients receive stents). Stent becomes a part of body in about four weeks.

How is PTCA different from bypass surgery?
In bypass surgery, blood vessel(s) from the chest or leg is / are grafted to the coronary artery beyond its most diseased segment. This lets the blood detour past the narrowing to reach the heart. In PTCA, however, the obstructed part of the coronary artery is widened rather than bypassed. Both operations achieve the same result.

Can everyone who has chest pain have PTCA?
No. Whether you are a candidate for this procedure depends on a number of variables. The number of arteries showing blockages, number of segments blocked, type of blockage (focal or diffuse), diameter of vessels and functioning of your heart muscle etc. Only a doctor who's familiar with your case can determine the best form of treatment for you out of medication, PTCA or bypass.

Will I ever need to have another PTCA?
It's possible especially for those who do not take care in diet, exercise regimen, lifestyle, etc. The dilated part of the coronary artery may re-narrow in 15 to 20 percent of the people who've had PTCA. If this happens to you, your doctor will advise you if the procedure should be repeated. However, if there is no re-narrowing within six months, it is unlikely to occur thereafter.

How long does it last?
It usually takes about 45 min. to one hour, under a local anesthetic, and involves a short hospital stay of two to three days.

What are the risks involved?
Angioplasty has many of the same risks as coronary angiography. An additional risk is that in less than 1 percent of case, the artery being treated may close off suddenly in the initial few days after angioplasty. Very rarely you may need an urgent bypass surgery. Therefore, it should only be performed in a setting where an emergency heart surgery team is on standby.

Is it painful?

Not,really. About an hour before the procedure you will be given a sedative to help you relax. You may feel some chest heaviness when the balloon is inflated because blood flow in the artery is temporarily blocked. After the procedure, the place where catheter was inserted may be a little sore.

Preparation for PTCA at EHIRC
You will come to the hospital one or two days before the procedure for some tests. These may include an electrocardiogram (ECG), blood and urine tests and a chest x-ray. You will probably fast for about six hours before the procedure. Depending upon the schedule of cases in the Cath Lab, your doctor will advise whether you need to fast overnight, or may have light refreshment during the day of the procedure. Routine preparation includes being shaved in the area where the catheter will be inserted, and sometimes from chest to ankles and showering with an antiseptic solution to prevent infection.

What to expect after the procedure is over?
When the doctor is satisfied after the procedure, the catheters are removed but the plastic sheath is left in the groin for about 4 hours and then removed. A nurse will check your blood pressure. She will also check the insertion site for bleeding.

You will then return to an intensive care area for a few hours (usually till the sheath is removed) for monitoring and then into the ward. While you are in the CCU you will remain attached to the heart monitor. An IV line may also continue to give fluids and medications for a few hours. After the sheath removal, you will have to keep the leg straight for another about 6 hrs. You can start moving after that.

You may tell the nurse if:

• You feel any chest pain or feel discomfort at the insertion site.
• The arm or leg closest to the insertion site becomes numb or cold.
• You feel warmth or wetness around the insertion site - a sign that you may be bleeding.
• You have swelling near the insertion site.

What care do I have to take once back home?
You will be discharged after one or two days if you are feeling well and have no angina. Your doctor or his / her team doctor will talk to you about:

• Any guidelines you may have to follow
• What to expect, and
• Follow-up visits.

You may have a lump, the size of an olive under your skin at the insertion site. There may also be a bruise. These are common and should go away on their own after a few weeks. You can go back to your normal activities a day or two after getting home. You will most likely be able to return to work within 2 weeks. Try not to overdo it at first. Get an OK from your doctor before you start exercising or doing heavy work.

See your doctor regularly for checkups first within six months and then once every year. These visits help monitor your medication. Your doctor may subject you to exercise tests and see your progress.

Do I have to change my lifestyle?
Your doctor may refer you to a cardiac rehabilitation / lifestyle management program. This program can provide guidance, classes, and support groups to help you:

• Get exercise
• Quit smoking
• Lose exercise weight
• Lower your cholesterol
• Lower your blood pressure
• Control diabetes
• Reduce stress
• Cope better with change