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CORONARY HEART DISEASE

Cardiovascular disease - principally high blood pressure, heart disease and stroke - accounts for more than 40% of all deaths, killing almost a million Americans each year. It is the leading cause of death for both men and women of all ages and all ethnic groups . The rate of premature deaths from cardiovascular disease is, however, more prevalent among black Americans than white Americans. Cardiovascular disease is often thought to affect primarily men and older adults, but it is the primary cause of death among all Americans in middle age, causing more than 160,000 deaths in people between the ages of 35 and 64 each year. Women account for more than half of these deaths.

Every year about 1.5 million Americans have heart attacks. For 20-40% of them , the attack is the first symptom of heart disease and 1 in 3 heart attack victims do not survive their first attack.

About 58 million Americans live with some form of cardiovascular disease. The American Heart Association estimated for the year 2000 the cost of cardiovascular disease at $326.6 billion. This figure includes the cost of physicians and other professionals , hospital and nursing home services, medications, home health and other medical durables , plus lost productivity resulting from morbidity and mortality. The cost of quality of life and loss of human life is impossible to assess.

What is Coronary Heart Disease?

Heart disease is a serious and complex chronic disease that affects essentially all Americans. The immediate cause of heart disease is myocardial ischemia, a reduction in the blood flow to the muscles of the heart. This results from the narrowing or blockage of the arteries that feed the heart, or by an abnormal heartbeat that inhibits the flow of blood through the heart. The underlying causes may be hereditary or infectious, but the most common cause of myocardial ischemia is atherosclerosis , which is the development of constricting patches on the artery walls called plaque that are the result of a long process of fatty deposits, calcification, and immune and inflammatory responses.

Angina pectoris is a result of heart disease, as are myocardial infarction and cardiac arrhythmia. Angina pectoris is a pain in the chest that results from insufficient blood flow to the heart. People can get this at times other than during a heart attack. The underlying cause is usually restricted blood vessels in the heart due to plaque. When a person with such a restriction undertakes physical exertion, such as shoveling snow or running to catch a bus, the heart muscles require more blood than the restricted vessels are able to deliver and anginal pain is experienced . A person who experiences angina is at high risk for a heart attack.

Myocardial infarction (a heart attack) is the result of a blockage of an artery in the heart. It usually has a sudden painful onset, resembles angina but is more severe and does not subside.

Cardiac arrhythmia is defined as disruption within the electrical control of the heartbeat. The erratic beats or spasms cause slow blood flow to the heart , which damages the heart muscle and may even lead to death.

How does Coronary Heart Disease develop?

Heart disease develops slowly over time, and begins in childhood and early adolescence with the first fatty streaks being deposited in the arteries. These fatty deposits are primarily cholesterol-containing immune cells that start to build up near the junction of blood vessels where the blood tends to swirl around and small stress injuries to the vessels can occur.

The two earliest causes of heart disease are an excess of LDL cholesterol and an injury to the lining of the arteries. Toxins from smoking, poor diet or possibly infections can cause injury to the vessels. LDL particles start to migrate into the actual wall of the arteries and are pursued by cells of the immune system. These combine, get trapped and form the basis of fatty streaks. The muscle cells of the arterial wall take in cholesterol deposits and the plaque seems to trap cellular debris. As these plaques grow in size they start to attract calcium and fibrous material and to harden around a cholesterol core. This process is called atherosclerosis , meaning, "hardened pudding."

The blood vessels depend on their ability to flex under the load of the blood pumped out of the heart. The narrowed atherosclerotic vessels do not bend and so increase the work of the heart. The additional work needed to push the blood through the narrow hardened vessels, leads to high blood pressure and left ventricular hypertrophy (an enlarging of the heart). The aging plaque (a thrombus) forms a cap mostly made of blood clotting material. Under certain circumstances some of this clotted material may break off and form a free-floating clot (an embolus) that can then get stuck in any part of the body where the arteries get too narrow for it to pass through . The clot may lodge in the brain and lead to a stroke or it may end up in the arteries of the heart and lead to a heart attack. If it gets lodged in extremities, such as the leg, it is called peripheral artery disease. If the initial thrombus develops in the arteries of the heart, then there is a narrowing (stenosis) of the artery . As it progresses, a blockage or occlusion of these vessels will lead to ischemia and an infarction.

Studies show that some people can reverse heart disease by making their heart blockages shrink. This process is called "regression." Cholesterol lowering was involved in all of the studies that showed an improvement in blockages. Stopping smoking and being physically active are also important in reversing heart disease. Whether your blockages shrink or not, you can still reduce your risk of having a first or another heart attack.

The American Heart Association has identified several risk factors for coronary heart disease.

Some of the risk factors can be modified, treated or controlled, and some can't . The more risk factors a person has, the greater the chance that he or she will develop heart disease. Also the greater the level of each risk factor, the greater the risk . For example, a person with a total cholesterol of 300 mg/dL has a greater risk than someone with a total cholesterol of 250 mg/dL, even though all people with a total cholesterol greater than 240 are considered high-risk.

Risk factors you can control:

You can modify, treat or control most risk factors, by focusing on your lifestyle habits or, if needed, by taking medicine.

Tobacco smoke: Smokers' risk of heart attack is more than twice that of nonsmokers. Cigarette smoking is the biggest risk factor for sudden cardiac death; smokers have two to four times the risk of nonsmokers. Smokers who have a heart attack are more likely to die and die suddenly (within an hour) than are nonsmokers. Cigarette smoking also acts with other risk factors to greatly increase the risk for coronary heart disease. People who smoke cigars or pipes seem to have a higher risk of death from coronary heart disease (and possibly stroke), but their risk isn't as great as cigarette smokers. Constant exposure to secondhand smoke increases the risk of heart disease even for nonsmokers.
High blood cholesterol: The risk of coronary heart disease rises as blood cholesterol levels increase. A person's cholesterol level is affected by age, sex, heredity and diet. When combined with other risk factors such as high blood pressure and smoking , this risk goes even higher. LDL cholesterol, often called the bad cholesterol, like total cholesterol increases risk when high levels are present. HDL cholesterol, called the good cholesterol, lowers risk as levels increase. A sub-group of LDL called lipoprotein (a) also produces higher risk as the level increases. A common combination marker produced by dividing the total cholesterol level by the HDL cholesterol level is also used to measure heart disease risk. As this ratio increases, so does the risk. Medication can be taken to lower cholesterol levels but the years of high cholesterol prior to medication, will lead to some continued long-term risk. Although somewhat controversial, studies have indicated that triglycerides (mainly very low -density lipoproteins, VLDL) in the blood may also indicate a higher level of risk certain individuals.
Homocysteine: Several studies have shown that people who develop heart disease have higher levels of homocysteine in their blood. Homocysteine is a biological byproduct that is found at higher levels in the body when the intake of B vitamins, particularly folate (found in foods such as green vegetables), is low. Not all studies have shown the same homocysteine effect, so it has not yet received the widest support of scientists.
High blood pressure: High blood pressure increases the heart's workload, causing the heart to enlarge and weaken over time. It increases the risk of stroke, heart attack, kidney failure and congestive heart failure. When high blood pressure exists with obesity, smoking, high blood cholesterol levels or diabetes, the risk of heart attack or stroke increases several times.
Physical inactivity: An inactive lifestyle is a risk factor for coronary heart disease. Regular, moderate-to-vigorous exercise is important in preventing heart and blood vessel disease. Moderate-intensity activities are beneficial if done regularly and long term but more vigorous activities are associated with more benefits. Exercise can help control blood cholesterol, diabetes and obesity, as well as help lower blood pressure in some people.
Obesity and overweight: People who have excess body fat, especially if it is concentrated in the waist area, are more likely to develop heart disease and stroke even if they have no other risk factors. Excess weight causes a strain on the heart, raises blood pressure, blood cholesterol and triglyceride levels and lowers HDL (higher levels are healthier) cholesterol levels. It also increases your risk of diabetes development.
Stress: Scientists have noted a relationship between coronary heart disease risk and stress in a person's life, their health behaviors and socioeconomic status . These factors may affect established risk factors. For example, people under stress may overeat, start smoking or smoke more than they otherwise would.
Oral contraceptives: The early forms of birth control pills contained higher doses of estrogen and progestin and increased a woman's risk of heart disease and stroke, especially in older women who smoked heavily. New, lower-dose oral contraceptives carry a much lower risk of cardiovascular disease, except when combined with smoking or high blood pressure. For woman taking oral contraceptives that have other risk factors (especially smoking), her risk of developing blood clots and having a heart attack increases and rises even more after age 35. If you take birth control pills , get yearly medical check-ups of your blood pressure, triglyceride and glucose levels.
Alcohol: Drinking too much alcohol can increase triglycerides, raise blood pressure, cause heart failure, cancer and other diseases, lead to stroke and produce irregular heartbeats. It contributes to obesity, alcoholism, suicide and accidents. Some studies have shown that the risk of heart disease in people who drink moderate amounts of alcohol (an average of one drink for women or two drinks for men per day) is lower than in nondrinkers. One drink is defined as 1½ ounces of 80-proof spirits (such as bourbon, Scotch, vodka, gin, etc.), 1 ounce of 100-proof spirits, 4 ounces of wine, or 12 ounces of beer. It's not recommended that nondrinkers start using alcohol or that drinkers increase their intake.

Risk factors you cannot control:

Increasing age: About four out of five people who die of coronary heart disease are age 65 or older. At older ages, women who have heart attacks are more likely to die from them within a few weeks than men.
Gender: Men have a greater risk of heart attack than women, and they have attacks earlier in life. Even after menopause, when women's death rate from heart disease increases, man are still at higher risk.
Heredity and Ethnic group: Children of parents with heart disease are more likely to develop it themselves. Most people with a strong family history of heart disease have one or more other risk factors. African Americans have more severe high blood pressure than whites and therefore are at higher risk of heart disease. Heart disease risk is also higher among Mexican Americans, American Indians, native Hawaiians and some Asian Americans. These differences are partly due to higher rates of obesity and diabetes in some ethnic groups. You can't control your age, sex, race, and family history so it is extremely important to treat and control any other risk factors you may have.
Other Blood Measurements: Since heart disease involves blood clots, it is not surprising to find that clotting components in the blood are related to heart disease risk. Higher levels of fibrinogen in the blood indicate an increased risk of heart disease. Persistent low levels of inflammation in the body are also indicators of risk. The biological connection between low level inflammation and heart disease is not fully understood but may involve injury to the lining of the arteries. Markers of this condition include C-reactive protein and low albumin levels. Albumin is the most abundant protein in the blood serum and is slightly decreased by inflammation.
Type 2 diabetes: Even when glucose levels are under control, diabetes greatly increases the risk of heart disease and stroke. About two-thirds of people with diabetes die of some form of heart or blood vessel disease. If you have diabetes, it's critically important for you to manage your diabetes and control any other risk factors you may have, especially obesity.
Sex hormones: It's well known that men have more heart attacks than women do before the age of menopause. Several population studies show that the loss of natural estrogen as women age may contribute to a higher risk of heart disease after menopause . If menopause results from the surgical removal of the uterus and ovaries, the risk of heart attack rises sharply. If menopause occurs naturally, the risk rises more slowly. Hormones also affect blood cholesterol. Female hormones tend to raise HDL (higher levels are healthier) cholesterol and lower total blood cholesterol (lower levels are healthier). Male hormones do the opposite. If you've had a natural or surgical menopause, you may be considering estrogen replacement therapy (ERT) or hormone replacement therapy (HRT). ERT and HRT may increase a woman's risk of some diseases and health conditions. Your healthcare provider can help you make the best choice.