Angina (angina pectoris) is a type of temporary chest pain, pressure or discomfort that occurs when the heart is not getting enough oxygen. The most common underlying cause of angina is coronary artery disease, which occurs when the coronary arteries that supply the heart with oxygen-rich blood become blocked with plaque deposits. According to the American Heart Association, nearly 7 million Americans are diagnosed with angina every year, of which more than 4 million are women. If the angina occurs in predictable situations, such as during exertion or exercise, it is known as stable angina. However, if the painful episodes occur without warning, last longer than normal angina episodes and occur more frequently, it is known as unstable angina. This is a dangerous medical situation that requires prompt medical attention. Unstable angina may signal an impending heart attack. Treatment for angina usually includes a combination of lifestyle changes (e.g., quitting smoking) and medication (e.g., nitrates). If coronary artery disease is present, treatment options may also include medication, balloon angioplasty (with or without stenting) and bypass surgery.
Angina (angina pectoris) is a type of temporary chest pain, pressure or discomfort. It is often described as a crushing, burning, heavy sensation, and it frequently radiates from the chest into other parts of the body, such as the neck, arms, jaw and abdomen. In women, angina may be experienced as abdominal pain. Typical episodes of angina can last anywhere from two to 15 minutes. Almost 7 million Americans suffer from angina, and about 550,000 new cases are diagnosed each year, according to the American Heart Association. Angina occurs when the heart is temporarily deprived of oxygen, a condition called cardiac ischemia.
The most common cause of cardiac ischemia is coronary artery disease, a condition in which oxygen-rich blood cannot travel freely through coronary arteries that are severely hardened and narrowed (atherosclerotic) from plaque buildup and calcification. If the angina occurs at predictable times, usually after exercise or exertion, it is called stable angina. If the angina occurs at unpredictable times, including at rest, and lasts longer than typical angina episodes, it is known as unstable angina. Unstable angina may signal an impending heart attack.
People experiencing unstable angina should seek medical attention immediately. Besides coronary artery disease, other causes of cardiac ischemia and angina include problems with: The heart’s aortic valve, such as regurgitation (leaking) or stenosis (narrowing). The heart muscle, as in hypertrophic subaortic stenosis (also known as hypertrophic cardiomyopathy). The capillaries, which could lead to a diagnosis of microvascular angina or Cardiac Syndrome X. Coronary artery spasms, which could lead to a diagnosis of variant or Prinzmetal angina. This type of angina is rare, and may be considered a form of unstable angina. It almost always occurs when patients are at rest, typically between midnight and early morning hours. It is common for these patients to have “active” periods of variant angina, with frequent anginal episodes over a period of months. Two-thirds of people with variant angina have severe blockage in at least one major vessel.
There is also a greater risk of developing arrhythmias such as ventricular tachycardia and ventricular fibrillation. Cardiac ischemia can also lead to dangerous problems if underlying conditions are left untreated: Abnormal heart rhythms arrhythmias, which can lead to either syncope (fainting) or sudden cardiac death. Heart disease patients whose episodes are triggered by stress (e.g., frustration, hostility) are more likely to die from their heart condition. Severe or lengthy episodes can trigger a heart attack. The small effects of minor episodes can eventually lead to permanent weakening of the heart muscle (cardiomyopathy).
Signs and symptoms of angina
The most common symptom that people report when they have angina is chest pain, pressure or a vague chest discomfort. In fact, the term “angina pectoris” means “a choking sensation of the chest.”
An angina attack may feel like a squeezing vise or crushing pressure deep in the chest behind the breastbone (sternum), and may radiate into the back, neck, jaw, shoulders, arms and even fingers. People experiencing angina may also feel light-headed and have an abnormally fast or abnormal heartbeat (arrhythmia). Some people, especially women and individuals with diabetes, may have atypical, non-specific or vague symptoms.
Types and differences of angina
There are two main types of angina pectoris. The first is called classical or stable angina. According to current statistics from the American Heart Association, about 400,000 new cases of stable angina are reported annually in the United States. Stable angina occurs while (or just after) the heart has a need for extra oxygen. The heart needs extra oxygen during a variety of situations that put extra stress on the heart, which include: Cigarette smoking Eating and digesting a heavy meal Physical exertion, especially after eating Strong emotions, such as anger or frustration – even during a dream Sudden changes in temperature or altitude Stable angina attacks typically last anywhere from one to 15 minutes, with relief brought on by rest and/or medication. The pain or discomfort associated with episodes of stable angina typically reflects a temporary reduction in blood flow to the heart muscle, rather than permanent damage to the heart muscle.
Chest pain or discomfort that occurs at unpredictable times, including at rest, and does not resolve within 15 minutes (with or without medication) may be a sign of unstable angina. Another indication of unstable angina is an increase in frequency and/or severity of stable angina. Unstable angina is a dangerous medical condition that may signal the progression of underlying coronary artery disease. In some cases, unstable angina will be provoked after a plaque ruptures within the coronary arteries. This causes the artery to narrow, further restricting blood flow to the heart. Unstable angina may also be caused by blood clots that form on damaged plaque.
Episodes of unstable angina can occur at low levels of exertion, even when a person is at rest, and in individuals having no prior history of angina. Indeed, sudden and unrelieved chest pain may cause people to suspect they are having heart attack. Physicians therefore use caution and approach the situation as an emergency. This is because unstable angina can quickly develop to a heart attack, and cardiac enzyme levels may not indicate any heart muscle damage – or healing – until days after a heart attack. There is also an increased risk for life-threatening arrhythmias (e.g., ventricular tachycardia and ventricular fibrillation). It should be noted that some people have episodes of cardiac ischemia that produce no type of angina at all. These episodes are called silent ischemia. This type of cardiac ischemia is usually diagnosed from an exercise stress test. Studies have demonstrated that silent ischemia can be more common among certain ethnic or racial groups. For example, recent reports find that Asian Americans, in comparison to white Americans, experience significantly fewer episodes of ischemic chest pain. Other symptoms, however, occur more frequently, such as shortness of breath, fatigue and palpitations.
Diagnosis methods for angina
From the patient’s description of symptoms, a physician can usually determine whether angina is present during a physical examination. Words used to describe angina include tightness, squeezing, crushing, burning, choking or aching. Because angina is not specific in location, patients may not be able to tell exactly where it comes from. Instead, they may make a fist in the middle of their chest to demonstrate chest pain. This is called a Levine sign and may cause the physician to suspect angina. During an angina attack, a physician will assess a patient’s heartbeat, heart rate and blood pressure, which can be elevated. Various blood tests and/or a urine test may be ordered. From there, additional tests may be performed to determine the underlying cause of the angina, as well as the extent of any heart damage and coronary artery disease. These include:
An exercise stress test. An electrocardiogram (EKG) is performed while the patient exercises in a controlled manner on a treadmill or stationary bicycle at varied speeds and elevations. The reaction of the heart under exertion can be measured and evaluated. However, the EKG reading may be normal, even for a patient with extensive damage to the heart. Nuclear imaging. A nuclear imaging test is a test in which the patient is injected with a radionuclide substance, such as thallium, to produce contrasts (pictures) of the heart. Nuclear tests allow physicians to measure the uptake of blood or nutrients into the heart muscle, which provides a good picture of healthy versus unhealthy heart tissue.
Nuclear tests can also be given in conjunction with exercise as nuclear stress tests. Stress echocardiogram. A common type of stress test that combines EKG and echocardiogram to evaluate cardiac ischemia. While the patient is either exercising or has been given a medication that causes the heart to react as if the person were exercising the reaction of the heart under stress can be measured. Catheter-based techniques, including an angiogram. During this test, a special dye is delivered through a thin tube to the coronary arteries.
This dye appears on an x-ray (radiopaque) and helps physicians pinpoint the location and severity of blockages in the coronary arteries. Computed tomography uses multiple x-ray sensors, or an electron beam, to provide very detailed, three-dimensional images of the heart. This technique allows physicians to obtain very detailed images of the heart while it works. Both multi-sensor computed tomography, which can yield up to 64 angles during a single scan, and rapid electron beam computed tomography, which takes a scan during a single heartbeat, are also used to measure the degree of calcification in the coronary arteries.
These tests are useful for people with established heart disease because the degree of calcification is related to heart-attack risk. However, people who are very low risk of heart attack are not advised to undergo calcium scoring using computed tomography, and people who are at high risk should already be under intensive treatment and therefore are not advised to undergo calcium scoring.
Treatment options for angina
The course of treatment for angina will depend on the physician’s determination of its severity and the extent of underlying heart/vessel damage. The patient’s family medical history, particularly for heart disease, will also play a role in planning treatment. For most patients with mild, stable angina, a combination of medications and risk-reducing lifestyle changes is usually recommended. Lifestyle changes include: Eating a heart-healthy diet Improving cholesterol ratio Exercising regularly Controlling diabetes Controlling high blood pressure (hypertension) Achieving and maintaining a healthy weight Managing stress Quitting smoking (or not starting to smoke) Controlling depression and emotional factors Medications used to treat angina either increase the supply of oxygen to the heart muscle or reduce the heart’s need for oxygen.
These medications include: Nitrates (e.g., nitroglycerin) widen, or dilate, the walls of the blood vessels. These drugs allow more blood, and therefore oxygen, to reach the heart, thus lessening the pain associated with angina attacks. Nitrates can be taken during an angina attack and may rapidly provide relief of symptoms, or they can be administered as daily medications for long-term control. In cases of persistent anginal episodes, nitroglycerin can be added to other medications, such as beta blockers or calcium channel blockers. Beta blockers slow the heart’s resting rate and reduce the force of the accompanying heart muscle contraction, thus lessening the heart’s workload. Calcium channel blockers (calcium antagonists) block the entry of calcium into the cells, thus reducing the amount of calcium.
This widens (dilates) the coronary arteries and increases the heart’s blood flow. This class of drugs can also be used to treat coronary artery spasms associated with variant or Prinzmetal angina. Antiplatelet medications inhibit the formation of blood clots by decreasing the ability of platelets (the body’s natural blood-clotters) to bind together and form blood clots. These drugs are typically not prescribed to reduce angina, but to reduce the risk of heart attack associated with coronary artery disease, of which angina is a major symptom. Aspirin is the most common antiplatelet. A second novel therapy is the combination of aspirin and another antiplatelet, clopidogrel.
New data suggest that these two drugs produce an enhanced, additive effect in reducing the risk of embolism and other adverse events following an episode of unstable angina. Positive results are also being seen with combined aspirin and clopidogrel in coronary stenting. Anticoagulant medications inhibit the formation of blood clots by inhibiting any of a number of coagulation factors. These drugs are typically administered to people who are at high risk of blood clots causing a heart attack or stroke. Anticoagulants must be closely monitored to make sure there is not increased risk of bleeding. Individuals are encouraged to discuss with their physician any other medications or supplements they may be taking. For example, if a patient takes sildenafil in combination with nitrates it can provoke a dangerous drop in blood pressure. In January 2006, the U.S. Food and Drug Administration approved ranolazine, a new drug for the treatment of chronic angina.
Studies have shown that ranolazine is effective among patients with stable angina, but because it alters the heart rhythm, it is recommended only for patients who have failed other angina therapies. For most patients with more serious or worsening angina, especially those in whom significant damage has already been found, further procedures may be performed, including: Angioplasty is a procedure in which a balloon–tipped catheter is inserted into a partially blocked coronary artery and rapidly inflated. The balloon compresses the plaque, pushing it against the artery wall, to allow for freer blood flow. Angioplasty is often followed by the insertion of a stent. Stenting is a procedure in which a small wire mesh tube called a stent is placed into a damaged artery via a catheter, usually at the same time an angioplasty is performed, to support and stretch the artery walls and provide for unrestricted blood flow.
The development of drug-coated (drug-eluting) stents has helped to reduce the rates of re-narrowing (restenosis) following stenting and angioplasty. However, newer data have implicated drug-eluting stents with increased long-term risk of blood clots and researchers are currently studying the best application of stents. Atherectomy is a procedure in which a special catheter equipped with a grinding burr or blade is used to cut away plaque in the arteries. The plaque is then removed when the catheter is withdrawn from the artery, or the tiny pieces are absorbed into the bloodstream. This procedure is generally reserved for a small subset of patients because of the higher risks associated with the techniques.
Coronary artery bypass grafting (CABG) is major surgery that relies on grafts created from the patient’s own veins and arteries from elsewhere in the body (such as the internal mammary artery in the chest) to re-route the flow of blood around a blocked area of a coronary artery. Coronary artery bypass surgery may be performed with or without the heart-lung machine. If it is performed without the heart-lung machine, it is known as off-pump coronary artery bypass (OPCAB). Currently, about 25 percent of CABG operations are performed without the heart-lung machine. Minimally invasive direct coronary artery bypass (e.g., MIDCAB) is a newer, less invasive form of coronary artery bypass surgery. In this procedure, the physician operates through smaller, keyhole incisions in the patient’s side. It may be performed with or without use of the heart–lung machine. Because of the limited operating field, it is usually reserved for patients with more limited coronary artery disease and is often performed in conjunction with angioplasty. .
Transmyocardial revascularization (TMR), also known as transmyocardial laser revascularization (TMLR), is a newer surgical procedure in which a laser beam is used to make small holes in the heart to improve oxygenation to the heart muscle. This results in less chest pain.TMR may be an option for patients with severe angina that does not respond to medication. Earlier recommendations also reserved TMR for those not candidates for CABG or angioplasty. However, recent studies have shown benefit with CABG plus TMR, and even TMR with off-pump coronary artery bypass. When performed with bypass surgery, TMR may speed postoperative recovery and improve survival.
TMR is not recommended for those with a low ejection fraction or heart failure.A variation of TMR is called percutaneous myocardial revascularization (PMR), in which the laser is delivered through an artery via a catheter until it is arrives at the heart. Also known as percutaneous transmyocardial laser revascularization (PTMR), this procedure has shown to improve exercise tolerance and relief from angina pain. However, the medical community has only limited experience with this method. External counterpulsation (ECP or EECP) is a newer, noninvasive technique that may be considered for individuals having stable angina but not eligible for conventional revascularization techniques.
EECP uses blood pressure cuffs wrapped around the legs. As they are inflated and deflated, blood is pushed into the heart, improving circulation and reducing the heart’s workload. Though this technique does appear to give some patients clinical improvement, it has a limited application and has not been generally accepted. After surgery, medications such as anti-clotting agents and/or antioxidants (both vitamins and drugs) may help to prevent re-blockage of the arteries (restenosis). Researchers are reporting early success with gene therapy to improve blood supply to the heart and relieve angina in patients with cardiac ischemia. Focus has been in the area of therapeutic angiogenesis, an experimental treatment that promotes the creation of new blood vessels. One promising therapy involves the use of vascular endothelial growth factor (VEGF), a growth factor that promotes the creation of new blood vessels. VEGF is injected into the heart muscle in a solution containing a DNA plasmid. Once inside the heart, the DNA plasmid is taken up by the heart tissue and begins to stimulate the growth of new blood vessels. This is still an experimental technique, but has so far shown promise.
Prevention methods for angina
In addition to making healthy lifestyle changes and taking all medication as prescribed, patients are encouraged to become familiar with their family’s health histories. Although genetic factors such as disease history, ethnicity and gender cannot be changed, knowing them can help in measuring risk and creating an appropriate plan for making lifestyle changes. Finally, any marked changes in symptoms, such as having more attacks or having more painful attacks, may be a sign of worsening health and increased risk of heart attack. These changes should be brought to the attention of a physician as soon as possible.
Ongoing angina research
Research is ongoing to more clearly define which treatment plans are most effective in patients with unstable angina and other coronary syndromes. For example, some researchers favor a “routine early invasive” strategy, described as cardiac catheterization (with an angiogram) and catheter-based procedures within 24 to 48 hours after the episode.
Antiplatelet therapy (e.g., aspirin plus clopidogrel) is also administered. This approach maintains that appropriate therapy can best suit the patient once an angiogram is performed. Others propose a “selective invasive” strategy, which involves drug management first (e.g., antiplatelets, ischemia medications) along with exercise stress testing and nuclear or other imaging techniques.
An angiogram is performed when deemed necessary, followed by revascularization if needed. “Early” and “selective” strategies are also influenced by how high (or low) a patient’s risk is for heart attack or heart failure. Researchers have also found that B-natriuretic peptide (BNP) levels can reflect or correlate with the risk of heart failure and death in patients with unstable angina. BNP is produced in the heart muscle and released in response to stresses put on the walls of the ventricles (the heart’s lower chambers).
Researchers had already known that elevated BNP levels were associated with increased mortality in persons sustaining a heart attack and in those with heart failure. BNP measurements may be yet another useful tool in identifying high-risk (or low-risk) patients and, thereafter, tailoring the most effective treatment strategy for them.
Researchers have also observed that C-reactive protein (CRP), a “marker” of inflammation, can help identify angina patients who are at higher risk for developing a heart attack. Additional studies are focusing on advances in the diagnosis, treatment and prevention of conditions associated with angina:
- Non-invasive methods for diagnosing coronary artery stenosis
- New drug treatments
- Spinal cord stimulation
- Stem cell research for heart disease
- Hormone and angina relationship
- Cardiac rehabilitation for angina treatment
- Inflammatory markers for heart disease
- Timing of treatment