Coronary artery disease, also frequently referred to simply as "heart disease", happens when cholesterol and calcium builds up (called "plaque") inside the coronary arteries of the heart reducing the blood flow to the heart muscle. This process starts in childhood and slowly progresses based on many different risk factors including diabetes, tobacco use, hypertension, high cholesterol and genetics (family history). Once a severe blockage develops (greater than 70%) limiting blood flow to the heart muscle, chest pain or discomfort can occur which is called "angina".
A heart attack happens when a blood clot forms on top of a cholesterol plaque inside the coronary artery completely stopping blood flow to an area of the heart muscle (100% blockage). It is important to know that this blood clot actually forms on a minor blockage, thus a person may be completely fine one day and even be in very good shape, then suddenly the next day can have a heart attack.
Why do I have Coronary Artery Disease?
The development of cholesterol plaque starts at a very young age. This is why we need to be focused on the health of our children. Slowly over time, many factors injure the lining of the coronary arteries making them vulnerable to cholesterol depositing. These factors include:
Diabetes: Frequently diabetes is from poor diet and lack of exercise, but genetics do play a role in developing diabetes. Not overeating calories and staying physically active can help prevent diabetes from developing.
Tobacco use: The harsh chemicals that enter the blood stream from smoking damage the lining of the arteries causing inflammation. This leads eventually to cholesterol building up.
Hypertension: The high pressure inside the arteries in people with hypertension puts stress on the artery wall causing damage. Eventually, this can lead in plaque formation and heart disease.
High cholesterol: The more cholesterol in the blood stream, the easier it is for it to deposit in the wall of the artery. Some cholesterol in you body comes from your diet, however a majority is made in the liver. Thus, even a person with a very low cholesterol diet can still have high cholesterol levels and be at risk for heart disease.
Genetics: There are certain genetic factors that increase the risk of developing heart disease. Having a 1st degree relative (parent or sibling) that developed heart disease at a young age (male < 45 years old or female < 55 years old) is considered a major risk factor for heart disease.
How is Coronary Artery Disease Diagnosed?
Coronary artery disease can be diagnosed with different testing listed below.
Electrocardiography (ECG): This is an electrical tracing of the heart. A very easy test to perform (takes just a couple minutes), an ECG is usually the first step in diagnosing heart disease.
Coronary calcium scoring: This test is a quick scan of the coronary arteries to see if calcium has built up. A coronary calcium score is done using a CT scanner, no IV is needed, and it takes less than 1 minute. The higher the score, the higher the risk of the artery being blocked, however this test is not able to confirm the presence of blockage, just coronary calcium plaque.
Stress testing: A stress tests uses monitored exercise on a treadmill or medication through an IV to stress the heart, then imaging the heart is done to see if there is reduced blood flow to the heart muscle from a coronary blockage. Common types of stress tests include treadmill ECG tests, treadmill or medication induced nuclear stress tests, and stress echocardiography.
Coronary CT angiography: A coronary CT angiogram uses CT technology and IV dye to see the inside of the coronary arteries. This test is painless and quite accurate.
Coronary angiogram: A coronary angiogram is an invasive procedure. A small tube called a catheter is placed like an IV into the artery in the groin. The tube is then fed up the aorta all the way to the coronary arteries. Dye is then squirted into the coronary arteries. An x-ray camera is present to see the inside of the arteries and detect blockage. This is currently the most accurate way to find blockage, but it is invasive. The benefits include the ability to actually fix a blockage with an angioplasty or stent at the same time if a blockage is found.
What are the Symptoms of Coronary Artery Disease?
The symptoms of coronary artery disease are quite different from person to person which can make it a challenge for doctors to determine if a patient's symptoms are from coronary blockage (angina) or not. In regards to symptoms, there are three possible situations when severe coronary blockage is present.
Typical symptoms: The classic description of angina is a pressure or pain in the center of the chest which travels to the left arm. The pain is better at rest and worse with physical activity. There is frequently shortness of breath and excessive sweating present.
Atypical (unusual) symptoms: Some people thing they are having "heartburn" or "indigestion". Sometime the pain is located in the right side of the chest, down both arms, in the jaw or in the back. Some people experience angina as simply shortness of breath without any pain at all.
No symptoms: Surprisingly, some people can have severe blockage of the coronary arteries and not have any symptoms. Even "silent heart attacks" can occur without symptoms.
What is the treatment of Coronary Artery Disease?
Treatment of coronary artery disease includes prevention and relieving symptoms. Focusing on controlling the above mentioned risk factors is crucial. Medications can be give to patients with coronary artery disease both to prevent plaque from worsening and to relieve symptoms and are listed below.
Aspirin: Aspirin slightly thins the blood by blocking the ability of cells called platelets to form blood clots.
Nitroglycerine: Available in a sublingual (under the tongue), patch, or long-acting pill form, nitroglycerine helps relax the coronary arteries to improve blood flow.
Statins: The most effective medication currently available to stop plaque from progressing, the "statins" work by blocking the liver enzyme that makes cholesterol. First discovered in the same fungus that penicillin was found, there is ample evidence that statins prevent heart attack, stroke and death. Common examples are Lipitor, Crestor and Zocor.
Beta-blockers: These medications block adrenaline in the system. When adrenaline levels are high, the heart has to work harder and symptoms of angina are more likely.
Important Links for Patients
Mayo Clinic - Coronary Artery Disease
Web MD - Coronary Artery Disease
Cleveland Clinic - Coronary Artery Disease
Important Links for Students
Coronary Artery Disease STEMI Review - LearnTheHeart.com
LearnTheHeart.com Blog: Top 5 MI ECG Patterns you MUST Know
LearnTheHeart.com Blog: Coronary Calcium Score - No Doctors Order???