Cardiovascular disease is the No. 1 killer in America, affecting more than 13 million Americans. Among the different cardiovascular ailments coronary artery diasese is one of the most prevalent entities and great advances have taken place recently in this field.
What is coronary artery disease?
Coronary artery disease is atherosclerosis of the coronary arteries. Atherosclerosis occurs when the arteries become clogged and narrowed, restricting blood flow to the heart. Without adequate blood, the heart becomes starved of oxygen and vital nutrients it needs to work properly.
How does coronary artery disease develop?
Your coronary arteries are hollow tubes. Inside, they are smooth and elastic, allowing blood to flow freely.
Before your teen years, fat starts to deposit in the blood vessel walls. As you get older, the fat builds up. This causes slight injury to your blood vessel walls. In an attempt to heal itself, the cells release chemicals that make the walls stickier.
Then, other substances such as inflammatory cells, proteins and calcium that travel in your bloodstream start sticking to the vessel walls. The fat and other substances combine to form a material called plaque. The plaque builds up and narrows the artery (atherosclerosis).
Over time, the inside of the arteries develop plaques of different sizes. Many of the plaque deposits are hard on the outside and soft and mushy on the inside. The hard surface can crack or tear, exposing the soft, fatty inside. When this happens, platelets (disc-shaped particles in the blood that aid clotting) come to the area, and blood clots form around the plaque. This causes the artery to narrow even more. Sometimes, the blood clot breaks apart by itself, and blood supply is restored.
Over time a narrowed coronary artery may develop new blood vessels that go around the blockage to get blood to the heart. However, during times of increased exertion or stress, the new arteries may not be able to supply enough oxygen-rich blood to the heart muscle.
In other cases, the blood clot may totally block the blood supply to the heart muscle, causing what is called an acute coronary syndrome. This is actually a name given to three serious conditions:
- Unstable angina: can often be relieved with oral medications, is unstable and may progress to a heart attack. Usually more intense medical treatment or a procedure is required to treat this acute coronary syndrome.
- Non-ST segment elevation myocardial infarction (NSTEMI): This heart attack, or MI, does not cause changes on an electrocardiogram (ECG). However, chemical markers in the blood indicate that damage has occurred to the heart muscle.
- ST segment elevation myocardial infarction (STEMI): This heart attack, or MI, is caused by a prolonged period of blocked blood supply. It affects a large area of the heart muscle, and causes changes on the ECG and chemical markers in the blood.
Some people have symptoms that tell them that they may soon develop an acute coronary syndrome, others may have no symptoms until something happens, and still others have no symptoms of the acute coronary syndrome at all.
What is ischemia?
When plaque and fatty matter narrow the inside of an artery to a point where it cannot supply enough oxygen-rich blood to meet your heart's needs, cramping of the heart muscle occurs. This is called ischemia.
Ischemia of the heart can be compared to a cramp in the leg. When someone exercises for a very long time, the muscles in the legs cramp up because they're starved for oxygen and nutrients. Your heart, also a muscle, needs oxygen and nutrients to keep working. If its blood supply is inadequate to meet the heart muscle's needs, ischemia occurs, and you may feel chest pain or other symptoms.
Ischemia is most likely to occur when the heart demands extra oxygen. This is most common during:
- Exertion (activity)
- Excitement or stress
- Exposure to cold
When ischemia is relieved in a short period of time (less than 10 minutes) with rest or medications, you may be told you have "stable coronary artery disease" or "stable angina."
Coronary artery disease can progress to a point where ischemia occurs even at rest.
What are the symptoms of coronary artery disease?
The most common symptom is angina or "angina pectoris." Angina can be described as a discomfort, heaviness, pressure, aching, burning, numbness, fullness, squeezing or painful feeling. It can be mistaken for indigestion or heartburn. Angina is usually felt in the chest, but may also be felt in the left shoulder, arms, neck, back or jaw.
Other symptoms that can occur with coronary artery disease include:
- Shortness of breath
- Palpitations (irregular heart beats, skipped beats or a "flip-flop" feeling in your chest)
- A faster heartbeat
- Weakness or dizziness
Women often have different symptoms of coronary artery disease than men. For example, symptoms of a heart attack in women include pain or discomfort in the chest, left arm or back; unusually rapid heartbeat; shortness of breath; and/or nausea or fatigue. It is important to get help right away if any of these symptoms occur.
Learn to recognize your symptoms and the situations that cause them. Call your doctor if you begin to have new symptoms or if they become more frequent or severe. If you or someone you are with experience chest discomfort, especially with one or more of the symptoms listed above, donít wait longer than a few minutes (no more than 5) before calling 9-1-1 to get help.
If you have angina and have been prescribed nitroglycerin, call your doctor or have someone take you to the nearest emergency room if pain persists after taking three doses (taken at five-minute intervals) or after 15 minutes.
Emergency personnel may tell you to chew an aspirin to break up a possible blood clot, if there is not a medical reason for you to avoid aspirin.
Ischemia, and even a heart attack, can occur without any warning symptoms. This is called silent ischemia. It can occur among all people with heart disease, though it is more common among people with diabetes.
How is coronary artery disease diagnosed?
Your doctor can tell if you have coronary artery disease by:
- Talking to you about your symptoms, medical history, and risk factors.
- Performing a physical exam.
- Performing diagnostic tests, including an electrocardiogram (ECG or EKG), exercise stress tests, cardiac catheterization and others. These tests help your doctor evaluate the extent of your coronary heart disease, its effect on the function of your heart, and the best form of treatment for you. Research into new testing procedures, such as coronary computed tomography angiogram (CTA), may change the way coronary artery disease is diagnosed in the future.
Tests used to predict increased risk for coronary artery disease:
- Complete lipid profile
- Calcium score screening heart scan
How is coronary artery disease treated?
Treatment for coronary artery disease involves reducing your risk factors, taking medications, possibly undergoing invasive and/or surgical procedures, and seeing your doctor for regular visits.
Reduce your risk factors. This involves making lifestyle changes. If you smoke, you should quit. You will need to make changes in your diet to reduce your cholesterol, keep your blood pressure in check, and keep blood sugar in control if you have diabetes. Low-fat, low-sodium, low-cholesterol foods are recommended. Limiting alcohol is also important. You should increase your exercise/activity level to help achieve and maintain a healthy weight and reduce stress. But, check with your doctor before starting an exercise program. It is also important to control high blood pressure and maintain tight control of diabetes to reduce your risk of coronary artery disease.
Medications. If making lifestyle changes isn't enough to control your heart disease, medications may be needed to help your heart work more efficiently and receive more oxygen-rich blood. The medications you are on depend on you and your specific heart problem.
Surgery and other procedures. Common procedures to treat coronary artery disease include balloon angioplasty (PTCA), stent placement and coronary artery bypass surgery. All of these procedures increase blood supply to your heart, but they do not cure coronary heart disease. You will still need to decrease your risk factors to prevent future disease.
When these traditional treatments are not an option, doctors may suggest other less traditional therapies. Some are under current research:
- Transmyocardial laser revascularization, or TMR. TMR, or Transmyocardial Laser Revascularization, is a treatment aimed at improving blood flow to areas of the heart that were not treated by angioplasty or surgery. A special carbon dioxide (CO2) laser is used to create small channels in the heart muscle, improving blood flow in the heart. Frequently it is performed along with coronary artery bypass surgery.
- EECP. For patients who have persistent angina symptoms and have exhausted the standard treatments without successful results, Enhanced External Counterpulsation (EECP) may stimulate the openings or formation of collaterals (small branches of blood vessels) to create a natural bypass around narrowed or blocked arteries. EECP is a non-invasive treatment for people who have chronic, stable angina; who are not receiving adequate relief from angina by taking nitrate medications; and who do not qualify for an invasive procedure such as bypass surgery, angioplasty or stenting.
- Angiogenesis. Investigators are studying several substances that, when given through the vein or directly into the heart, may trigger the heart to grow new blood vessels to increase blood flow to the heart muscle.