What Is Stable Angina?

Senior woman holding chest in pain
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Angina refers to the symptoms (usually chest pain or chest discomfort) produced by ischemia of a portion of the heart muscle — that is, when the heart muscle is not receiving enough oxygen. The most common cause of angina is coronary artery disease (CAD).

What Is Stable Angina?

When a doctor makes a diagnosis of angina, the next step is to determine whether it is“stable” or “unstable” angina.

Unstable angina — in which symptoms occur at rest, or with trivial exertion, or with unusual frequency — is usually a form of acute coronary syndrome, and must be treated as a medical emergency. Unstable angina is caused by a rupture in an atherosclerotic plaque.

Fortunately, most people with CAD have stable angina.

Stable angina is caused by a stable plaque that has not ruptured, but instead is producing a partial, fixed blockage in a coronary artery. This partial blockage usually permits adequate blood flow to the heart muscle during periods of rest, so at rest there is no angina. However, the partial blockage also limits the maximum blood flow the artery is able to provide. So, at times when the heart muscle needs to work harder, such as during physical exertion or emotional stress, the blood flow cannot increase sufficiently to meet the increased demands on the heart muscle. The oxygen-starved muscle becomes ischemic, and angina occurs.

Once physical exertion is stopped — likely because the patient begins experiencing angina — the oxygen needed by the heart muscle drops down to its baseline level. Within a few minutes, the ischemia resolves and the angina goes away.

Characteristics of Stable Angina

Patients with stable angina usually have no symptoms at all while at rest or during mild activity, since the blood flow to their heart muscle is adequate under these conditions. Angina typically occurs with exertion, and often in a way that is fairly reproducible and predictable. For instance, a person with stable angina may notice symptoms only when climbing a second flight of stairs, or after walking more than three blocks.

Because stable angina tends to be reproducible, doctors can often use a stress test to make a rough estimate of the degree of blockage being produced by the culprit plaque. Angina that occurs after 30 seconds on a treadmill is likely to be caused by a plaque that is producing a lot of obstruction. If the angina only occurs after 10 minutes, the degree of blockage is likely to be much less severe.

Similarly, serial stress testing can be used to judge the adequacy of treatment, and to give the patient some idea of how much exertion they can perform without cardiac ischemia.

Treating Stable Angina

The goal in treating stable angina is threefold: to relieve or reduce the symptoms of angina, to try to prevent the further progression of atherosclerotic plaques, and to try to prevent the more severe consequences of CAD — namely, myocardial infarction, heart failure, and death.

The treatment needed to accomplish all of these goals can be complicated, and often involves making some fairly significant medical decisions. Anyone who has angina needs to understand the issues involved in making these decisions.

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Article Sources
  • Fihn SD, Gardin JM, Abrams J, et al. 2012 ACCF/AHA/ACP/AATS/PCNA/SCAI/STS guideline for the diagnosis and management of patients with stable ischemic heart disease: executive summary: a report of the American College of Cardiology Foundation/American Heart Association task force on practice guidelines, and the American College of Physicians, American Association for Thoracic Surgery, Preventive Cardiovascular Nurses Association, Society for Cardiovascular Angiography and Interventions, and Society of Thoracic Surgeons. Circulation 2012; 126:3097.