Angina: Chest Pain Caused by Coronary Artery Disease (CAD)
- This type of chest pain comes and goes.
- Angina usually lasts for about 10 minutes or less.
- Angina may feel like pressure or a squeezing pain in your chest.
- Angina can sometimes be mistaken for indigestion.
- You may also feel pain in your shoulders, arms, neck, jaw or back.
- Angina can be triggered by exercise, stress, cold weather or eating a large meal.
- The pain tends to get worse with activity and stop when you rest.
Symptom of Myocardial Ischemia
Angina is not really a condition; it is a symptom of another condition called myocardial ischemia, which occurs when the heart does not get as much blood as it needs.
Typically, myocardial ischemia occurs when the arteries supplying the heart with blood become blocked or narrowed in a condition called coronary artery disease (CAD).
Artery blockage is most commonly caused by buildup of fat and cholesterol known as plaque. When arteries become clogged with plaque, it is known as known as atherosclerosis.
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Types of Angina
Stable angina is the most common type, occurring when the heart is working harder than normal. Stable angina has a regular pattern. If you know you have it, you can figure out how to recognize the pattern and know in advance when the pain is going to come. The pain typically goes away in a few minutes after you rest or take your angina medicine. Stable angina isn't a heart attack, but it indicates that a heart attack is more likely in the future.
Unstable angina has no pattern. It can take place with or without physical exertion and cannot be relieved by resting or taking medicine. Unstable angina is extremely dangerous and requires emergency treatment. It is a predictor of an imminent heart attack.
Also known as Prinzmetal's angina, variant angina is fairly rare and tends to affect younger people more than stable and unstable angina. It usually occurs while you're at rest. The pain, which can be severe, usually occurs between midnight and early morning and can be relieved by medicine. Variant angina is caused by a spasm in the artery wall rather than atherosclerosis. The spasm causes the vessel to narrow temporarily.
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Risk Factors for Angina
- High cholesterol. Elevated levels of low-density lipoprotein (LDL) or "bad" cholesterol and/or low levels of high-density lipoprotein (HDL) or "good" cholesterol. This can help increase the buildup of plaque in the arteries.
- High blood pressure. Uncontrolled blood pressure can help harden and thicken the arteries. In general, your blood pressure should be less than 140/90.
- Family history of heart disease
- Age. Your risk for coronary artery disease (CAD) increases with age. For men, the risk increases sharply after age 45. For women, the risk jumps after age 55.
- Smoking. Nicotine constricts your blood vessels, and carbon monoxide can damage their inner lining. Smoking can also raise cholesterol and blood pressure. It also reduces the amount of oxygen getting your body's tissues.
- Diabetes. Blood sugars should be kept under control.
- Obesity. Your body mass index (BMI) should be under 25.
- High fat diet
- High salt diet
- Inactivity. You should exercise at least three times per week. Speak to your doctor before beginning an exercise program.
- Stress. Activities designed to manage stress may reduce your risk of CAD.
- Metabolic syndrome. This is a collection of conditions that includes high blood pressure, high triglycerides, elevated insulin levels and excess body fat around the waist.
- Sleep apnea. This is a condition in which your breathing stops or gets very shallow while you are sleeping.
- High levels of C-reactive protein (CRP), a marker for inflammation. There is emerging research suggesting that high levels of this protein in the blood may raise the risk of developing CAD or having a heart attack.
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Causes of Angina
Angina is a symptom of coronary artery disease (CAD) and is caused by reduced blood flow to your heart muscle.
Narrowing of the Arteries (Atherosclerosis)
The narrowing of the arteries in CAD is caused by a process called atherosclerosis. People with atherosclerosis have a build-up of a substance called plaque inside the wall of their arteries.
Plaque is made up of fat, cholesterol, calcium deposits, and white blood cells that have gotten into the artery wall. The plaque causes the wall to "bulge" into the inside of the artery where the blood normally flows. The bulge can partly or completely restrict the flow of blood in a particular artery.
Lack of Oxygen (Ischemia)
When blood flow is restricted, the heart muscle does not get the oxygen that it needs to function properly. Angina is the symptom of this lack of oxygen, called ischemia.
Stable angina occurs when you increase the heart's work load as a result of exercise. A blockage of CAD limits the extra flow required by the extra work load causing angina. When exercise is discontinued, the anginal pain resolves.
Unstable angina is caused when narrowed arteries are further blocked by a ruptured plaque and blood clot. This is a warning sign for complete blockage or heart attack.
Variant angina, which is rare, is caused by a spasm, or contraction, in a coronary artery, causing it to narrow temporarily. It is not related to atherosclerosis.
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Diagnosis of Angina
Your doctor will ask you about your symptoms, family history and risk factors. He or she will ask specific questions about your chest pain, asking you to describe it in detail.
If you go to the emergency room with chest pain, some of the following tests will be ordered immediately. These tests will determine if you are having angina or a heart attack. If you have a stable pattern of angina, other tests may be done to determine the severity of your disease. If your doctor thinks you have coronary artery disease (CAD), he or she will probably do one or more of the following tests:
These tests check for levels of certain fats, cholesterol, sugar and proteins called troponins in the blood that help determine if you have risk factors for coronary artery disease or if you are having a heart attack.
Electrocardiogram (EKG or ECG)
This is a painless, noninvasive test in which patches with electrodes are attached to your skin to measure electrical impulses produced by your heart.
These impulses are recorded as waves displayed on a monitor or printed out on graph paper. The test can reveal evidence of a previous heart attack or one that is in progress. Heart rhythm is also captured with an EKG.
This is a portable device that records all of your heartbeats over an extended period, usually either 24 or 48 hours. You wear small patches with electrodes on your chest that are connected by wires to a small, portable recorder. The recorder can be clipped to a belt, kept in a pocket, or hung around your neck.
During the time you're wearing a Holter monitor, you do your usual daily activities. This is used to monitor heart rhythm for an extended period of time.
This test uses sound waves to create a moving picture of your heart.
- Provides information about the size and shape of your heart and how well your heart chambers and valves are functioning.
- Identifies areas of poor blood flow to the heart, areas of heart muscle that aren't contracting normally, and previous injury to the heart muscle caused by poor blood flow.
The test is noninvasive and is performed by placing a probe on your chest wall. It is the same technique used in sonograms in pregnant women.
During a stress test, you exercise to make your heart work harder and beat faster. An EKG is recorded and blood pressure is monitored during exercise. The technician will be asking you about the presence of symptoms such as chest pain or shortness of breath.
Sometimes imaging is also done. This can be done with an echocardiogram as described above or by using a radioactive dye and xray equipment to image the heart's motion with exercise. If imaging is performed with your stress test, resting images (without exercise) are compared to stress images (after exercise) to look for changes in heart function that are related to blood flow patterns.
Coronary Angiogram or Catheterization
To directly see the pattern of blood flow in your arteries, your doctor may want to perform a coronary catheterization. This involves injecting a dye into your arteries in what is called an angiogram.
The dye is delivered through a long, thin, flexible tube called a catheter that is threaded through a leg artery into the coronary arteries. This is called catheterization.
The dye outlines areas of blockages on x-ray images. If a blockage is found and needs treatment, a balloon can be pushed through the catheter and inflated to open the artery or arteries in question. A stent or tiny wire mesh tube can then be inserted to keep the artery open.
This procedure is done in the hospital.
A computerized tomography (CT) scan uses X-rays and computers to get detailed pictures of the body. Coronary artery calcification CT scans can detect calcium in the coronary arteries which may indicate the presence of coronary artery disease. A CT coronary angiogram uses x-ray dye (contrast) to look at blood flow patterns within the coronary arteries to detect blockages. This provides information similar to the catheter based angiogram, but is not as invasive.
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Treatments for Angina
In some cases, coronary artery disease can be managed with lifestyle changes that include reducing risk factors. These include:
- Quitting smoking
- Modifying your diet
- Keeping your blood pressure under control
- Exercising (check with your doctor before beginning any exercise program)
- Reducing stress
If lifestyle changes aren't enough to control your coronary artery disease, you may need to take one or more medications to help your heart and arteries function better so that you receive sufficient oxygen-rich blood. These include:
- Cholesterol-lowering drugs: These drugs, often called statins, can decrease the amount of cholesterol in the blood, especially LDL or "bad" cholesterol. The drugs can also increase the amount of HDl or "good" cholesterol. The drugs can reduce the deposits that clog coronary arteries.
- Aspirin: Your doctor may recommend you take a daily aspirin tablet or other blood thinner to help reduce the tendency for your blood to clot.
- Beta-blockers: These are drugs that slow your heart rate and lower your blood pressure, reducing your heart's demand for oxygen.
- Nitroglycerin: This medication is taken during an angina attack, usually in the form of a tablet placed under your tongue. The drugs control chest pain by opening up the coronary arteries.
If you have a severe blockage in one or more arteries, you may benefit from a procedure known as angioplasty or percutaneous coronary intervention or revascularization (PCI).
An angioplasty can:
- Improve blood flow to your heart
- Relieve chest pain
- May be able to prevent a heart attack
An angioplasty opens blocked or narrowed coronary arteries. During angioplasty, a thin tube with a balloon on the end is threaded through a blood vessel to the narrowed or blocked coronary artery. Once in place, the balloon is inflated to push the plaque that is blocking your artery against the artery wall. This widens the artery and restores the flow of blood. A thin wire mesh tube called a stent may be placed in the artery permanently to keep the artery open. Some stents are coated with medication to help keep the artery open.
An angioplasty is done in the hospital and can take from 30 minutes to three hours. It is done under local anesthesia to numb the area of the groin where the catheter is inserted. Afterwards, you must remain in bed for at least another six hours. You may be able to go home the same day, but more often you will need to spend the night in the hospital.
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Coronary Artery Bypass Graft (CABG) Surgery
In coronary artery bypass graft (CABG) surgery, arteries or veins from other areas in your body are used to bypass or go around your narrowed coronary arteries. CABG can improve blood flow to the heart, relieve pain and possibly prevent a heart attack. A CABG is open-heart surgery. As a result, it is often used in cases where multiple coronary arteries are blocked or where the blockages are not suitable for angioplasty or stenting.
About CABG Surgery
CABG surgery involves exposing the heart through either the breastbone or the ribs. The operation typically includes the use of a heart-lung machine, which takes blood from the heart, adds oxygen, and then pumps it back into the body. Your surgeon may take an artery from the chest wall or remove a section of vein from your leg. These vessels are then grafted to the blocked arteries above and below the blocked areas. After the grafts are sewn into place, the heart-lung machine is turned off. The breastbone is wired together and the chest is closed. You are under general anesthesia during the operation. The CABG operation takes four to five hours.
Afterwards, you will be taken to the ICU where you will be on a heart monitor, have a breathing tube in your mouth, and a catheter in your bladder. You will also have temporary pacing wires and drainage tubes in your chest, and have several intravenous catheters in your neck and arms. You will probably remain in the hospital for four to five days and should be able to return to office-type work in four to six weeks. Because the bypass arteries can also clog, you must pay close attention to your diet, take aspirin and other medications as prescribed by your doctor, exercise regularly and maintain a healthy lifestyle to keep this from happening.
Off-Pump Beating-Heart CABG Surgery
In some cases, your surgeon may want to perform your bypass while your heart is still beating. This operation uses special equipment to stabilize or quiet the heart down while the surgery is ongoing. The heart-lung machine is not used. The remaining details of the surgery are the same as conventional CABG. The goal of off-pump bypass surgery is to decrease the risks associated with the use of the heart lung machine, such as stroke, renal failure and need for blood transfusion. Not everybody is a candidate for off-pump CABG.
Endoscopic or Minimally Invasive CABG Surgery
Traditional CABG surgery — with or without the use of a heart-lung machine — requires a large incision dividing the breastbone. In endoscopic CABG surgery, your surgeon performs the bypass through a smaller incision or incisions, using a tiny endoscopic camera and smaller instruments. Also, the heart-lung machine is not used The operation is associated with less post-operative pain, a shorter hospital stay and a shorter recuperation. Not everybody is a candidate for endoscopic CABG. In most cases, it is reserved for those who need just one blocked artery bypassed.
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