About coronary artery disease
What is coronary artery disease?
What is heart disease?
The heart is like any other muscle in body and it requires adequate blood supply to provide oxygen to allow the muscle to contract and pump. Not only does the heart pump blood to the rest of the body, it also pumps blood to itself via the coronary arteries. These arteries originate from the aorta (the major blood vessel that carries oxygenated blood away from the heart) and then branch out along the surface of the heart.
When one or more coronary arteries narrow, it may make it difficult for adequate blood to reach the heart, especially during exercise. This can cause the heart muscle to ache like any other muscle in the body. Should the arteries continue to narrow, it may take less activity to stress the heart and provoke symptoms. The classic symptoms of chest pain and shortness of breath due to atherosclerotic or coronary artery disease are called angina.
Should one of the coronary arteries become completely blocked, usually due to a blood clot that forms, blood supply to part of the heart muscle is completely lost and that piece of muscle dies. This is called a heart attack or myocardial infarction (myo=muscle + cardia=heart + infarction= tissue death).
Heart disease, for this article, will be limited to describing the spectrum of atherosclerosis or hardening of the arteries that ranges from minimal blockage that may produce no symptoms to complete obstruction that presents as a myocardial infarction. Other topics, such as myocarditis, heart valve problems, and congenital heart defects will not be covered.
What are the symptoms for coronary artery disease?
If your coronary arteries narrow, they can't supply enough oxygen-rich blood to your heart — especially when it's beating hard, such as during exercise. At first, the decreased blood flow may not cause any coronary artery disease symptoms. As plaque continues to build up in your coronary arteries, however, you may develop coronary artery disease signs and symptoms, including:
Chest pain (angina). You may feel pressure or tightness in your chest, as if someone were standing on your chest. This pain, referred to as angina, usually occurs on the middle or left side of the chest. Angina is generally triggered by physical or emotional stress.
The pain usually goes away within minutes after stopping the stressful activity. In some people, especially women, this pain may be fleeting or sharp and felt in the neck, arm or back.
- Shortness of breath. If your heart can't pump enough blood to meet your body's needs, you may develop Shortness of breath or extreme Fatigue with exertion.
Heart attack. A completely blocked coronary artery will cause a heart attack. The classic signs and symptoms of a heart attack include crushing pressure in your chest and pain in your shoulder or arm, sometimes with Shortness of breath and Sweating.
Women are somewhat more likely than men are to experience less typical signs and symptoms of a heart attack, such as neck or jaw pain. Sometimes a heart attack occurs without any apparent signs or symptoms.
When to see a doctor
If you suspect you're having a heart attack, immediately call 911 or your local emergency number. If you don't have access to emergency medical services, have someone drive you to the nearest hospital. Drive yourself only as a last resort.
If you have risk factors for coronary artery disease — such as high blood pressure, high cholesterol, tobacco use, diabetes, a strong family history of heart disease or obesity — talk to your doctor. He or she may want to test you for the condition, especially if you have signs or symptoms of narrowed arteries.
What are the causes for coronary artery disease?
Coronary artery disease is thought to begin with damage or injury to the inner layer of a coronary artery, sometimes as early as childhood. The damage may be caused by various factors, including:
- High blood pressure
- High cholesterol
- Diabetes or insulin resistance
- Sedentary lifestyle
Once the inner wall of an artery is damaged, fatty deposits (plaque) made of cholesterol and other cellular waste products tend to accumulate at the site of injury in a process called atherosclerosis. If the surface of the plaque breaks or ruptures, blood cells called platelets will clump at the site to try to repair the artery. This clump can block the artery, leading to a heart attack.
What are the treatments for coronary artery disease?
The goal is to maximize the quantity and quality of life and prevention is the key to avoid heart disease and optimize treatment. Once plaque formation has begun, it is possible to limit its progression by maintaining a healthy lifestyle with routine exercise, diet, and by controlling high blood pressure, high cholesterol, and diabetes.
A baby aspirin may be used for its antiplatelet activity, making platelets (one type of blood cells that help blood clot) less sticky and decreasing the risk of heart attack.
Medications may be prescribed in patients with heart disease to maximize blood flow to the heart and increase efficiency of the pumping function of the heart.
Beta blocker medications help block the action of adrenaline on the heart, slowing the heart rate. These medications also help the heart beat more efficiently and decrease the oxygen requirements of the heart muscle during work.
Calcium channel blockers also help the heart muscle contract and pump more efficiently.
Nitrates help dilate arteries and increase blood flow to the heart muscle. They may be short-acting to treat acute angina symptoms or long-acting preparations may be prescribed.
Should there be significant stenosis or narrowing of the coronary arteries, angioplasty and/or stenting (described above) may be considered to open the blocked areas. These procedures are performed in conjunction with cardiac catheterization. Depending upon the patient's anatomy and the extent of the blockage present, coronary artery bypass graft surgery (CABG) may be required.
What are the risk factors for coronary artery disease?
Risk factors for coronary artery disease include:
- Age. Simply getting older increases your risk of damaged and narrowed arteries.
- Sex. Men are generally at greater risk of coronary artery disease. However, the risk for women increases after menopause.
- Family history. A family history of heart disease is associated with a higher risk of coronary artery disease, especially if a close relative developed heart disease at an early age. Your risk is highest if your father or a brother was diagnosed with heart disease before age 55 or if your mother or a sister developed it before age 65.
- Smoking. People who smoke have a significantly increased risk of heart disease. Exposing others to your secondhand smoke also increases their risk of coronary artery disease.
- High blood pressure. Uncontrolled high blood pressure can result in hardening and thickening of your arteries, narrowing the channel through which blood can flow.
- High blood cholesterol levels. High levels of cholesterol in your blood can increase the risk of formation of plaque and atherosclerosis. High cholesterol can be caused by a high level of low-density lipoprotein (LDL) cholesterol, known as the "bad" cholesterol. A low level of high-density lipoprotein (HDL) cholesterol, known as the "good" cholesterol, can also contribute to the development of atherosclerosis.
- Diabetes. Diabetes is associated with an increased risk of coronary artery disease. Type 2 diabetes and coronary artery disease share similar risk factors, such as obesity and high blood pressure.
- Overweight or obesity. Excess weight typically worsens other risk factors.
- Physical inactivity. Lack of exercise also is associated with coronary artery disease and some of its risk factors, as well.
- High stress. Unrelieved stress in your life may damage your arteries as well as worsen other risk factors for coronary artery disease.
- Unhealthy diet. Eating too much food that has high amounts of saturated fat, trans fat, salt and sugar can increase your risk of coronary artery disease.
Risk factors often occur in clusters and may build on one another, such as obesity leading to type 2 diabetes and high blood pressure. When grouped together, certain risk factors put you at an even greater risk of coronary artery disease. For example, metabolic syndrome — a cluster of conditions that includes elevated blood pressure, high triglycerides, low HDL, or "good," cholesterol, elevated insulin levels and excess body fat around the waist — increases the risk of coronary artery disease.
Sometimes coronary artery disease develops without any classic risk factors. Researchers are studying other possible factors, including:
- Sleep apnea. This disorder causes you to repeatedly stop and start breathing while you're sleeping. Sudden drops in blood oxygen levels that occur during sleep apnea increase blood pressure and strain the cardiovascular system, possibly leading to coronary artery disease.
- High sensitivity C-reactive protein. High sensitivity C-reactive protein (hs-CRP) is a normal protein that appears in higher amounts when there's inflammation somewhere in your body. High hs-CRP levels may be a risk factor for heart disease. It's thought that as coronary arteries narrow, you'll have more hs-CRP in your blood.
- High triglycerides. This is a type of fat (lipid) in your blood. High levels may raise the risk of coronary artery disease, especially for women.
- Homocysteine. Homocysteine is an amino acid your body uses to make protein and to build and maintain tissue. But high levels of homocysteine may increase your risk of coronary artery disease.
- Preeclampsia. This condition that can develop in women during pregnancy causes high blood pressure and a higher amount of protein in urine. It can lead to a higher risk of heart disease later in life.
- Alcohol use. Heavy alcohol use can lead to heart muscle damage. It can also worsen other risk factors of coronary artery disease.
- Autoimmune diseases. Conditions such as rheumatoid arthritis and lupus (and other inflammatory rheumatologic conditions) have an increased risk of atherosclerosis.