When Coronary Artery Disease (CAD) causes chest pain, it is called Angina Pectoris. Approximately 6.2 million people in the U.S. have been diagnosed with Angina Pectoris. It is usually described as a heaviness, pressure, squeezing, or aching in the substernal (front, central area) of the chest. Anginal pains can radiate to the left shoulder or down the left arm, back, neck, jaw and only occasionally down the right arm. It occurs with exertion and resolves with rest. Usually it lasts only a few minutes. Sometimes an onset can occur during a heavy meal, cold weather or increased emotional stress. Angina should not be worsened by deep breaths, bending over, pressing on the chest, or twisting in certain positions. Sometimes it can be confused with indigestion.
While the physical examination of someone with angina is often normal, sometimes the signs of other diseases that are risk factors for CAD can be detected during the exam.
Certain laboratory tests will be abnormal during a heart attack (CPK, CPK-MB, Troponin, Myoglobin) when heart muscle cells die. However, these tests will be normal during angina because the lack of oxygen to the cells is temporary and cell death does not occur. Your physician may want to check your total cholesterol level as well as HDL and LDL levels. Also your blood sugar or fasting blood sugar should be checked to see if diabetes is present.
ST segment (the line between the QRS complex and the T wave) depression and T wave changes (usually inversion) are the hallmarks of ischemia. However, an EKG in someone with a history of CAD and angina often has a "normal" reading. If an EKG is done during an episode of angina, sometimes the typical ST segment depression can be seen.
Because a resting EKG often results in a "normal" reading for a person with angina, your physician may need to have a stress test to evaluate the presence of CAD. As described earlier, if the characteristic ST segment depression occurs during stress testing, especially if typical chest pain occurs, the test is considered "positive".
A cardiac catheterization test can be used to determine if CAD is present, how severe it is and determine if a coronary artery bypass graft is needed. It can definitely exclude CAD if it is not present. This test is performed for many reasons. It is especially important if:
- angina symptoms continue, even though your condition is being treated by a physician
- severe ischemia is present on a stress test and symptoms suggestive of CAD are present, but the doctor is not able to determine the diagnosis with other tests
- multiple hospital admissions for chest pain occur in which heart attack is ruled out but the presence of CAD has not been determined
During a cardiac catheterization, blockages are treated as a balloon is blown up inside the coronary arteries, thereby opening the passage. This procedure is called Percutaneous Transluminal Coronary Angioplasty (PTCA) or just plain angioplasty. Here is an example of how an angioplasty works:
The most important factors that determine the course and outcome of Coronary Artery Disease (CAD) are the functional ability of the Left Ventricle and the number, location and severity of the blockages. Although it obviously can lead to heart attacks and death, many people lead long productive lives despite CAD.
The treatment of CAD consists of the prescription of medications, controlling risk factors, treating aggravating conditions and sometimes angioplasty or coronary artery bypass surgery. Conditions that aggravate CAD include anemia, lung disease, hypertension, obesity and hyperthyroidism; treating these problems can help with CAD. The treatment of risk factors helps to slow down the progression of CAD as well as prevent CAD.
Some medications that are used to treat angina include:
- Nitrates - Nitrates are medications that come in many forms such as sublingual (under the tongue) pills or spray, nitrate pills (Isosorbide), and nitroglycerin patches. These medications work by dilating the veins and therefore decreasing the oxygen requirements of the heart. They also dilate the coronary arteries and consequently increase blood flow to the heart muscle. Sublingual nitroglycerin is used during an episode of angina. One tablet or a single spray under the tongue can be used every five minutes up to three times. A burning feeling is usually felt under the tongue and frequently a headache occurs. Anginal chest pain usually resolves within a few minutes. Nitrate pills and patches can also be used for angina. These medications tend to have less effectiveness over time due to tolerance. Therefore, a medication free period of 8 to 12 hours per day is recommended.
- Beta-Blockers - Beta-Blockers decrease the heart rate and the force of the heart's contraction by blocking the effects of the sympathetic nervous system on the heart. This class of medications reduces heart attacks and decreases mortality in patients who have had heart attacks. Medications in this class include Propranolol, Metoprolol, and Atenolol. These medications are extremely useful but sometimes have side effects that may limit their use in some people.
- Aspirin - Platelets are necessary for clotting. Aspirin is an anti-platelet medication that prevents platelets from clotting and clumping on blood vessel walls. If this were to occur in a coronary artery, a heart attack could result. The exact dose of Aspirin is not clear, but usually a baby aspirin, one-half of an adult aspirin, or one adult aspirin is given per day. Aspirin may have side effects such as stomach upset or bleeding, or allergies. People who are allergic to aspirin can take another anti-platelet medication called Ticlopidine.
Often a person with angina has pain with a predictable amount of exertion. This is called stable angina. Unstable angina exists when the angina worsens. Unstable angina is defined as more frequent episodes of anginal chest pain with less exertion, anginal chest pain at rest, or new onset of severe angina. This usually means a worsening of the Coronary Artery Disease (CAD), with a larger obstruction. This condition can quickly lead to a heart attack and is especially true if unstable angina is associated with certain EKG changes. Persons with unstable angina are hospitalized to treat the unstable angina and to determine if a heart attack has occurred.
Nitrates (such as nitroglycerin) are used to relieve chest pain. This can be given sublingually or intravenously (through the vein). Heparin, a potent anti-clotting drug, is used to prevent the worsening obstruction in the coronary artery from becoming complete. Recently, new anti-clotting medications have been introduced called IIb/IIIa inhibitors (Abciximab or Tirofiban) that are used in unstable angina. In addition, patients are started on aspirin and often a beta-blocker as well. If these medications are insufficient, then a cardiac catheterization can be performed to determine the location and severity of any blockages. Often an angioplasty can be performed at the same time. Sometimes an angioplasy is not possible, then a coronary artery bypass graft may be necessary.
In the next section, we'll discuss heart attacks.