Angina (angina pectoris) is a type of temporary chest pain, pressure or discomfort. In one type of angina, called stable angina, the attacks happen only when the heart needs extra oxygen, like when a person climbs a long flight of stairs or jogs across the street. In another type of angina, called unstable angina, angina attacks may occur more frequently, with less activity – even when a person is at rest. When the heart is not getting enough oxygen-rich blood (cardiac ischemia), angina can be considered a distress call or warning signal. The most common cause of cardiac ischemia is coronary artery disease. The coronary arteries supply the heart with oxygen-rich blood. When they are hardened and narrowed (atherosclerotic), oxygen-rich blood may not be able to travel freely to the heart, triggering cardiac ischemia and (often) angina.

Not only can cardiac ischemia cause angina, but it can also lead to dangerous problems over time if underlying conditions are left untreated.

Fortunately, treatment is available. Treatment usually includes a combination of “lifestyle changes” that people can make on their own (e.g., quitting smoking) and taking medication (e.g., nitrates). If coronary artery disease is present, treatment options may then include medication, balloon angioplasty (with or without stenting) and either traditional bypass surgery or less invasive surgeries such as MIDCAB and OPCRES.

What is angina?
Angina (angina pectoris) is a type of temporary chest pain, pressure or discomfort. It occurs during episodes in which the heart is not receiving enough oxygen-rich blood (cardiac ischemia). The most common cause of cardiac ischemia is coronary artery disease, because oxygen-rich blood cannot travel freely through coronary arteries that are severely hardened and narrowed (atherosclerotic) from plaque build-up and calcification.

Not only can episodes of cardiac ischemia cause angina, but they can also lead to dangerous problems over time if underlying conditions are left untreated:

• They can cause 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) 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 add up and lead to permanent weakening of the heart muscle (cardiomyopathy).

Angina is the primary symptom of coronary artery disease. Other causes of cardiac ischemia and angina may stem from:

• 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 – a condition in which patients experience chest pain but without coronary artery blockage.
• 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 8 a.m. 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.

What does angina feel like?
The main experience 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 also be felt in the back, neck, jaw, shoulders, arms, and even fingers. People experiencing angina may also feel light-headed and have an abnormally fast or irregular heartbeat (arrhythmia).






What are the two main types of angina?
There are two main types of angina pectoris. The first type is called classical or stable angina. 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 the following:

• 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 occur between 6:00 a.m. and noon. They tend to last anywhere from one to 15 minutes, with relief brought on by rest and/or medication. It is emphasized that the pain or discomfort associated with episodes of stable angina typically reflects a temporary reduction in bloodflow to the heart muscle, rather than permanent damage to the heart muscle. Chest pain or discomfort that does not resolve within 15 minutes (with or without medication) may be a sign of unstable angina. Another indication of unstable angina is when there is an increase in frequency and/or severity of stable angina. This may be due to an inflammatory process that ensues when plaque ruptures or cracks, in turn actually increasing the area of the blockage. It may also be due to enlarging blood clots forming on the damaged plaque.

Since blood flow becomes more restricted, 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, unremitting chest pain may understandably cause one to suspect he or she is having a 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 (if blood flow is completely obstructed), and that 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.

How is angina diagnosed?
From the patient’s description of his or her symptoms, a physician can usually determine whether angina is present. During an angina attack, a physician will take note of a patient’s heart rate (usually elevated), blood pressure (possibly elevated) and heartbeat. 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. Up to 50 percent of patients who suffer from silent ischemia show normal EKG readings.
• 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.
• 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, in which an x-ray is taken of the heart’s arteries, using a catheter to deliver a special (radiopaque) dye that helps the physician to pinpoint the location and severity of major blockages.
• Ultrafast computed tomography (also called Electron Beam Computed Tomography or EBCT). This noninvasive test detects calcification in the coronary arteries, which may impact on the risk of future cardiac events (e.g., heart attack or death). To date, study methods, results and recommendations have been limited by several factors. One has been that EBCT may not effectively evaluate chest pain in younger individuals, in whom calcified plaque is not typically found. Another is that EBCT has not demonstrated the ability to independently assess the risk of future cardiac events. In other words, evidence of calcification has not removed the need for the diagnostic tests described above. To address these issues, several ongoing studies are seeking to more clearly define the role of EBCT and calcification in predicting cardiac events.

What is the treatment 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. For most patients with mild angina, a combination of medications and risk-reducing lifestyle changes is usually recommended. Lifestyle changes include the following:

• Learning your family medical history
• Eating a heart-healthy diet
• Improving your cholesterol ratio
• Exercising regularly
• Controlling diabetes
• Controlling high blood pressure (hypertension)
• Achieving and maintaining a healthy weight
• Managing your stress
• Quitting smoking (or not starting to smoke)
• Controlling chronic depression

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 the following:

• 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. 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. Aspirin is the most common antiplatelet drug.
• Anticoagulant medications inhibit the formation of blood clots by inhibiting any of a number of coagulation factors. Antiplatelet drugs have been the mainstay in anticoagulant treatment. However, alternative medications are demonstrating benefit. Among these is enoxaparin, a form of heparin. Enoxaparin has shown a safe, effective and predictable action in improving the outcomes in unstable angina and other coronary syndromes. 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.

Individuals are encouraged to discuss with their physician any other medications or supplements they may be taking. For example, if a patient currently takes sildenafil for the treatment of erectile dysfunction, nitroglycerin (and all other nitrates) should not be prescribed. This is because nitrates and sildenafil in combination can provoke a dangerous drop in blood pressure. 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 damaged artery, where the balloon is inflated. The balloon compresses the plaque, pushing it against the artery wall, to allow for freer blood flow. Angioplasty often precedes 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 to support and stretch the artery walls and provide for unrestricted blood flow.
• Directional atherectomy is a procedure in which a bladed catheter is used to cut away plaque in the arteries. The plaque is then removed when the catheter is withdrawn from the artery.
• Coronary artery bypass grafting uses pieces of the patient’s own veins and arteries from elsewhere in the body (such as the internal mammary artery in the chest) to create a detour that re-routes the flow of blood around a blocked area of a coronary artery.
• Minimally invasive bypass surgery is a newer, less invasive procedure used in selected traditional coronary bypass candidates with only one or two blocked arteries. In this procedure, a heart-lung machine is not necessary, the breastbone (sternum) does not have to be cracked, the incision is smaller, the cost of the procedure is less than that of a traditional bypass and it is likely the patient will recover more quickly because of less trauma and pain.
• Transmyocardial revascularization (TMR), also known as transmyocardial laser revascularization (TMLR), is a newer surgical procedure in which a laser beam makes small holes in the heart to aid in increasing blood flow. With improved blood flow, more oxygen can reach the heart, resulting 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 coronary artery bypass (CABG) or angioplasty. However, recent studies have shown benefit with CABG plus TMR and even TMR with off-pump coronary artery bypass – OPCAB. TMR is not recommended for those having low ejection fraction or congestive heart failure.
• 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.

After surgery, medications such as anti-clotting agents and/or antioxidants (both vitamins and drugs) may help to prevent re-blockage of the arteries.






Can angina be prevented?
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.






What are the recent developments in angina research?
Recent studies are seeking 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, anti-ischemia medications) along with exercise stress testing and nuclear or other imaging techniques. An angiogram is done 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.