Several types of angina exist:
- "Stable" angina, the most common type of angina, often recurs in a regular, predictable pattern. A specific stimulus provokes the angina.
- "Unstable” angina may first appear as new onset angina, a very severe episode of angina or as frequently recurring bouts of angina that increase in frequency or severity. The term "unstable angina" is also used when symptoms suggest a heart attack but hospital tests do not support that diagnosis.
- Prinzmetal's or variant angina. This type is rare and is caused by vasospasm, a spasm that narrows the coronary artery and lessens the flow of blood to the heart.
- Microvascular angina. Patients with this condition experience chest pain but have no apparent coronary artery blockages. Microvascular angina can be treated with some of the same medications used for angina pectoris.
Episodes of angina occur when the heart's need for oxygen increases beyond the oxygen available from the blood nourishing the heart. Unstable angina may occur when there is an existing narrowing of the artery by a cholesterol plaque and thrombosis (clot) occurs on top of the plaque. Thrombosis is caused by platelet aggregation as well as thrombin formation – and we will see below that therapy can be aimed at these two processes. Physical exertion is the most common trigger for angina. Other triggers could include emotional stress, extreme cold or heat, heavy meals, alcohol, and cigarette smoking. Risk factors for coronary artery disease include family history, high blood pressure, increased cholesterol, smoking, diabetes, male gender, and advancing age.
An episode of angina specifically is not a heart attack but exists within a continuum where the heart attack is the final manifestation of CAD. Angina pain means that some of the heart muscle in not getting enough blood temporarily--for example, during exercise, when the heart has to work harder.
Angina implies an underlying coronary heart disease. Patients with angina are at an increased risk of heart attack compared with those who have no symptoms of cardiovascular disease. In contrast, when the pattern of angina changes—if episodes become more frequent, last longer, or occur without exercise—the risk of heart attack is much higher.
Treatment of angina involves more broadly treatment for CAD. The most commonly prescribed drug for angina is nitroglycerin, which is taken when discomfort occurs or is expected. Other medications considered important for treatment include aspirin and thienopyridine therapy (Clopidogrel, Ticlopidine) – both aimed at inhibiting platelet function; heparin, low molecular weight heparin or Coumadin (blood thinners) aimed at anti-thrombin therapy; beta blockers (which slow the heart rate and lessen the force of the heart muscle contraction, reducing heart oxygen demand), calcium channel blockers (which dilate the arteries and allow more oxygen to the heart); and cholesterol lowering medications (which may reduce the size of plaques and stop formation of plaques). The exact combination of therapy is dependent upon the individual patient’s history and physical examination, but nitrates and beta blockers are the first drugs of choice.
If the patient continues to have angina or is a high risk patient, the physician may recommend cardiac catheterization, where a small tube is placed into a forearm or groin artery and dye is injected to look at the blood vessels of the heart (coronary arteries). Based on this test, the physician my recommend surgery, balloon angioplasty or stent placement.Doctors may recommend surgery or angioplasty if drugs fail to treat the CAD and its symptoms (like angina) or if the risk of heart attack is high. Coronary artery bypass surgery is an operation in which a blood vessel is grafted onto the blocked artery to bypass the blocked or diseased section so that blood can get to the heart muscle. An artery from inside the chest (an "internal mammary" graft) or long vein from the leg (a "saphenous vein" graft) may be used.
Balloon angioplasty (PTCA) involves inserting a catheter with a tiny balloon at the end into a forearm or groin artery. The balloon is inflated briefly to open the vessel in places where the artery is narrowed.
Physicians may also use a mechanical device to open the arteries, called a stent. A stent is applied to the vessel via a catheter and is expanded to keep the artery open. The stents may be used as initial therapy or used after a balloon angioplasty depending upon the findings at cardiac catheterization.
Other catheter techniques are also being developed for opening narrowed coronary arteries, including laser and radiofrequency devices applied by means of catheters.
To help prevent angina:
- Adopt good eating habits, moderating alcohol consumption
- Quit smoking
- Lower cholesterol by diet and if necessary medications
- Lose excess weight
- Exercise
- Avoid emotional upsets
A person who has angina should learn the pattern of his or her angina—what causes an angina attack, what it feels like, how long episodes usually last, and whether medication relieves the attack. If the pattern changes sharply or if the symptoms are those of a heart attack, one should get medical help immediately, perhaps best done by seeking an evaluation at a nearby hospital emergency room.
Exercise may increase the level of pain-free activity, relieve stress, improve the heart's blood supply, and help control weight. The idea is to gradually increase stamina by working at a steady pace and avoiding sudden bursts of effort. A person with angina should start an exercise program only with the doctor's advice.
