Angina

Angina is the term for the chest pain or discomfort that occurs when cardiac muscle does not receive adequate blood flow. This is usually caused by the buildup of fat and cholesterol within the coronary arteries, and can therefore be considered a sign of heart disease. The three main types of angina are stable angina, unstable angina, and Prinzmetal's angina. Each causes the same type of pain but occurs in a different pattern and under different circumstances. Individuals with angina should eliminate modifiable [Page 140]risk factors, such as cigarette smoking, hypertension, high cholesterol, and poorly managed diabetes mellitus to prevent a worsening of their heart disease. Physicians may also recommend medications or surgery to manage angina.

The most common cause of angina is coronary atherosclerosis, or the accumulation of fat and cholesterol that forms stiff plaques within the coronary arteries. Narrowing of the coronary arteries by fatty plaques can limit the amount of blood flow that reaches the heart. Because blood supplies oxygen to body tissues, an increase in cardiac work or a temporary decrease in blood flow through the coronary arteries in someone with coronary atherosclerosis can prevent the heart from receiving enough oxygen. Myocardial ischemia, or inadequate oxygenation of the heart, causes the symptom known as angina. Individuals describe this chest pain as pressure, tightness, or tingling in the center of the chest that sometimes radiates to the neck, jaw, shoulders, arms, wrists, or upper abdomen. Pain usually lasts less than 15 minutes and can vary in intensity.

Stable angina is sometimes called demand angina because it occurs when oxygen supply does not meet cardiac demand. Cardiac oxygen demand increases with physical activity or emotional stress. When an increase in oxygen demand cannot be met with an increase in blood flow due to narrowing of the coronary arteries, pain occurs in a predictable, reproducible manner and subsides once the demand decreases.

Unstable angina is pain that occurs at rest, with lower levels of physical activity or with increasing frequency than it did when an individual was said to have stable angina. Individuals with new-onset chest pain are also included in this group. Unstable angina is caused by a temporary reduction in cardiac oxygen supply that is not caused by an increase in physical activity. Decreases in coronary blood flow are caused by blood clots that form within coronary arteries and adhere temporarily to plaques. The clots, in turn, may release vasoconstrictors that induce spasms of the blood vessel and further decrease blood flow. Although the clots rapidly dissolve on their own, unstable angina is a worrisome symptom because without treatment, individuals often go on to have a heart attack later in life.

Prinzmetal's angina, also known as vasospastic angina, is chest pain that occurs at rest without a decrease in cardiac exercise capacity. Myocardial ischemia is caused by coronary artery spasms in individuals with underlying coronary atherosclerosis. Some individuals go on to have a heart attack within three months of diagnosis, but spontaneous remission eventually occurs in most.

There are a number of ways to manage angina, including habit modification, medication, and in severe cases, surgical cardiac revascularization. Many individuals are able to control their angina through smoking cessation, weight loss, stress management, exercise, and proper control of hypertension, high cholesterol, and diabetes mellitus. Others may also require medications that decrease cardiac workload and lower oxygen demand (beta-adrenergic blocking agents and calcium channel blocking agents) or those that increase coronary blood flow by dilating the vessels (short- and long-acting nitrates). Individuals with severe coronary atherosclerosis may need to undergo surgical revascularization to restore adequate blood flow to the heart. This can be done through procedures called coronary artery bypass grafting (CABG), balloon angioplasty, or cardiac stenting.

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