Cardiovascular Diseases

AHA Scientific Position
Cigarette smoking is the most important preventable cause of premature death in the United States. It accounts for nearly 440,000 of the more than 2.4 million annual deaths. Cigarette smokers have a higher risk of developing several chronic disorders. These include fatty buildups in arteries, several types of cancer and chronic obstructive pulmonary disease (lung problems). Atherosclerosis (buildup of fatty substances in the arteries) is a chief contributor to the high number of deaths from smoking. Many studies detail the evidence that cigarette smoking is a major cause of coronary heart disease, which leads to heart attack.How does smoking affect coronary heart disease risk?
Cigarette and tobacco smoke, high blood cholesterol, high blood pressure, physical inactivity, obesity and diabetes are the six major independent risk factors for coronary heart disease that you can modify or control. Cigarette smoking is so widespread and significant as a risk factor that the Surgeon General has called it "the leading preventable cause of disease and deaths in the United States."

Cigarette smoking increases the risk of coronary heart disease by itself. When it acts with other factors, it greatly increases risk. Smoking increases blood pressure, decreases exercise tolerance and increases the tendency for blood to clot. Smoking also increases the risk of recurrent coronary heart disease after bypass surgery.
Cigarette smoking is the most important risk factor for young men and women. It produces a greater relative risk in persons under age 50 than in those over 50.
Women who smoke and use oral contraceptives greatly increase their risk of coronary heart disease and stroke compared with nonsmoking women who use oral contraceptives.
Smoking decreases HDL (good) cholesterol. Cigarette smoking combined with a family history of heart disease also seems to greatly increase the risk.What about cigarette smoking and stroke and peripheral arterial disease?

Studies show that cigarette smoking is an important risk factor for stroke. Inhaling cigarette smoke produces several effects that damage the cerebrovascular system. Women who take oral contraceptives and smoke increase their risk of stroke many times. Smoking also creates a higher risk for peripheral arterial disease and aortic aneurysm.What about cigar and pipe smoking?

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 that of cigarette smokers. This is probably because they're less likely to inhale the smoke. Currently there's very little scientific information on cigar and pipe smoking and cardiovascular disease, especially among young men, who represent the vast majority of cigar users.What about passive or secondhand smoke?
The link between seconhand smoke (also called environmental tobacco smoke) and disease is well known, and the connection to cardiovascular-related disability and death is also clear. About 37,000 to 40,000 people die from heart and blood vessel disease caused by other people's smoke each year. Of these, about 35,000 nonsmokers die from coronary heart disease, which includes heart attack.

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Coronary heart disease

Atherosclerotic heart disease can be thought of as a wide spectrum of disease of the heart. At one end of the spectrum is the asymptomatic individual with atheromatous streaks within the walls of the coronary arteries (the arteries of the heart). These streaks represent the early stage of atherosclerotic heart disease and do not obstruct the flow of blood. A coronary angiogram performed during this stage of disease may not show any evidence of coronary artery disease, because the lumen of the coronary artery has not decreased in calibre.

Over a period of many years, these streaks increase in thickness. While the atheromatous plaques initially expand into the walls of the arteries, eventually they will expand into the lumen of the vessel, affecting the flow of blood through the arteries. While it was originally believed that the growth of atheromatous plaques was a slow, gradual process, recent evidence suggests that the gradual buildup may be complemented by small plaque ruptures which cause the sudden increase in the plaque burden due to accumulation of thrombus material.

Intravascular ultrasound image of a coronary artery (left), with color coding on the right, delineating the lumen (yellow), external elastic membrane (blue) and the atherosclerotic plaque burden (green). As the plaque burden increases, the lumen size will decrease.
Atheromatous plaques that cause obstruction of less than 70 percent of the diameter of the vessel rarely cause symptoms of obstructive coronary artery disease. As the plaques grow in thickness and obstruct more than 70 percent of the diameter of the vessel, the individual develops symptoms of obstructive coronary artery disease. At this stage of the disease process, the patient can be said to have ischemic heart disease. The symptoms of ischemic heart disease are often first noted during times of increased workload of the heart. For instance, the first symptoms include exertional angina or decreased exercise tolerance.

As the degree of coronary artery disease progresses, there may be near-complete obstruction of the lumen of the coronary artery, severely restricting the flow of oxygen-carrying blood to the myocardium. Individuals with this degree of coronary heart disease typically have suffered from one or more myocardial infarctions (heart attacks), and may have signs and symptoms of chronic coronary ischemia, including symptoms of angina at rest and flash pulmonary edema.
A distinction should be made between myocardial ischemia and myocardial infarction. Ischemia means that the amount of oxygen supplied to the tissue is inadequate to supply the needs of the tissue. When the myocardium becomes ischemic, it does not function optimally. When large areas of the myocardium becomes ischemic, there can be impairment in the relaxation and contraction of the myocardium. If the blood flow to the tissue is improved, myocardial ischemia can be reversed. Infarction means that the tissue has undergone irreversible death due to lack of sufficient oxygen-rich blood.

An individual may develop a rupture of an atheromatous plaque at any stage of the spectrum of coronary heart disease. The acute rupture of a plaque may lead to an acute myocardial infarction (heart attack).

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What is Cancer

Cancer is a group of diseases which affect the cells of the body. Normal cells reproduce themselves and divide in two. When cells begin growing too rapidly, and without order, a tumor is created. Many tumors are benign, meaning they will stay confined to the part of the body where they formed and can usually be removed. Some tumors, however, are malignant tumors that invade surrounding tissue, destroying healthy cells.

If unchecked, cells may break off and spread through the bloodstream to other parts of the body and create new tumors. This process of metastasis can have fatal results. Cancer can be divided into four groups.

Cancers that occur on the skin or an organ are called carcinomas. Those that occur in muscle tissue or bone are called sarcomas. Lymphomas are tumors of the lymphatic system, affecting lymph nodes in the neck, groin, armpits, liver, and spleen. Leukemias are cancers of the blood-making bone marrow.

Many factors may cause cancer. Scientists have found that smoking is associated with several cancers, and that high-fat diets and obesity may also increase your risk. Many cancers may be caused by environmental contamination by cancer promoting elements called carcinogens. Excessive exposure to sunlight is a factor in many skin cancers.

If you have a history of cancer in your family, talk to your doctor about the warning signs of cancer. Early detection is the key to effective treatment. For more information about cancer, contact your health care provider.

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