What is Coronary Artery Disease or Coronary Heart Disease?
Coronary Artery Disease (CAD), also called Coronary Heart Disease (CHD), is the most common type of heart disease. It is the leading cause of death in the United States in both men and women.
Coronary Artery Disease is the condition in which there is a narrowing or blockage of the coronary arteries, usually caused by atherosclerosis. Atherosclerosis is the buildup of plaque (made of cholesterol, fatty deposits, calcium and other substances found in the blood system) on the inner walls of the arteries. Plaque narrows the arteries and reduces blood flow to your heart muscle by physically clogging the artery. This narrowing also increases the risk of forming blood clots within the coronary arteries. This formation can decrease blood flow even more or completely occlude the artery. Without an adequate blood supply, the heart becomes starved of oxygen and the vital nutrients it needs to work properly. This can cause chest pain called angina to occur, and will cause death of the heart muscle which by definition is a heart attack.
What causes Coronary Artery Disease?
The coronary arteries are hollow tubes through which blood flows to the muscle of the heart. The walls of the coronary arteries are elastic and smooth. They are lined with a layer of cells called the endothelium. This layer of endothelium provides a barrier between the blood stream and the coronary artery walls. This lining regulates the function of the artery by releasing chemical signals in response to various stimuli.
CAD begins in the pre-teen years. The artery wall lining begins to show streaks of fat, and as you age these streaks of fat slowly build up. This build up can ultimately damage the ling of the artery. Once this injury has started other substances traveling through your blood stream, such as inflammatory cells, cellular waste products, proteins and calcium can begin to collect on these damaged areas. This collection of materials and fat becomes what is known as plaque.
As one ages these plaques can grow in size. The area of the paque that is exposed to the blood stream itself is hardened and smooth, but the inside remains soft. If this outer smooth surface cracks open then the inner soft area becomes exposed to the blood stream. This inner substance is an attractant to substances in the blood stream known as platelets. Platelets are particles in the blood supply and help in the formation of clots. This collection of clots can harm the heart by physically slowing or stopping blood flow. This collection of material can also cause an inappropriate narrowing caused by this irritant.
Once the narrowing or blockage happens the heart can not receive enough of the nutrient and oxygen rich blood that it needs to work efficiently. This decrease in oxygen can cause angina or a heart attack.
Angina is chest pain or discomfort that occurs when the oxygen demand of the heart is greater than is being delivered to the muscle. Angina is usually described as a tightness or squeezing in the chest. The pain can also extend to the shoulders, neck, jaw, arms or back.
The depletion of oxygen-rich blood to the muscle causes it to die. Without timely treatment, a heart attack can lead to serious complications and even death.
What Are the Major Risk Factors for Coronary Artery Disease (CAD)?
Many factors raise the risk of developing CAD. The more risk factors you have, the greater chance you have of developing CAD.
- Smoking. The nicotine can tighten or constrict blood vessels, and carbon monoxide damages the inner lining of arteries, making them more susceptible to atherosclerosis. Smoking also can raise cholesterol, increase blood pressure and decrease the amount of oxygen delivered to the tissues of the body.
- Diabetes. This is a disease in which the body’s blood sugar level is high because the body doesn’t make enough insulin or doesn’t use its insulin properly. Diabetes is associated with an increased risk of coronary artery disease.
- High Cholesterol. Abnormal levels of blood cholesterol can increase the risk of formation of atherosclerosis. Although abnormal cholesterol can be caused by a high level of low-density lipoprotein (LDL), known as “bad” cholesterol, A low level of high-density lipoprotein (HDL), known as “good” cholesterol, can also increase the risk of atherosclerosis.
- High blood pressure. A blood pressure of 140/90 mmHg is considered high. When blood pressure remains uncontrolled, the arteries of the body and heart become hardened and a thickened.
- Being overweight or obese. Having an excess of body fat especially around certain parts of the body increases the risk of heart disease.
- Family history of heart disease. There is an increased risk for developing heart disease when a close relative had heart disease. The risk is elevated most when a father or brother had coronary artery disease before 55 years of age or, a mother or sister before the age of 65
- Age. As your age increases, so does your risk for coronary disease. Males show a significant increase after age 45 and females after the age of 55.
- Metabolic syndrome. This is a group of risk factors linked to being overweight and obese that raises your chance for heart disease. These include high blood pressure, high blood sugar, high triglycerides, low HDL levels, and extra fat around the waist area.
- Physical inactivity. Lack of physical activity increases activity can worsen other risk factors which increase the risks of coronary artery disease.
Other Risk Factors for CAD:
- High Stress Levels. While high levels of stress can damage the arteries of the heart; stress is also a common trigger for heart attacks.
- Sleep apnea. There is a increased risk of developing heart disease, high blood pressure and stroke when sleep apnea is left untreated
- C-reactive protein. C-reactive protein (CRP) is a normal protein that increases when inflammation is present in the body. This increased level is thought to increase the risk of coronary artery disease.
- Alcohol. High levels of alcohol intake have been shown to damage the heart muscle and increase the risk factors of coronary artery disease.
- High triglyceride levels. Increased levels of triglycerides have been shown to increase the risk of coronary disease, especially in females.
What are the Signs and Symptoms of Coronary Artery Disease?
The most common symptom of CAD is angina. Angina is chest pain or discomfort. This occurs when the heart’s oxygen demand is greater than what the coronary arteries can supply.
Angina can vary from person to person. While the most common feeling is that of pain or pressure in the chest, others may experience varying symptoms from shoulder, neck, arm or jaw pain to feelings of indigestion or heartburn. Some other common complaints are: heaviness in the chest, a squeezing feeling around the chest, feeling that something is sitting on the chest, or numbness in the chest, shoulder or arms.
Other common symptoms that may be associated with coronary disease include: indigestion, nausea or vomiting, lightheadedness, fainting or passing out, sweating or “cold sweats”, irregular or rapid heart beats, and difficulty breathing. Some individuals especially the elderly may only experience a feeling of tiredness.
While the most common symptom is chest pain, there are individuals who suffer from CAD and have no signs or symptoms. This is often referred to as Silent Coronary Artery Disease.
If you experience any of the above signs or symptoms for greater that five minutes you should seek medical attention immediately. Call 911 Without delay!
How is Coronary Artery Disease Diagnosed?
There is no single tool for diagnosing CAD. Your doctor will review your medical history, symptoms, and perform a complete physical exam. This will guide the doctor in deciding which tests or procedures should be performed.
Blood tests. While no single blood test can diagnose coronary artery disease, the information can be combined with your medical history and physical exam to determine your risk. Abnormal levels of certain proteins, fats, levels of cholesterol or sugars can help identify your risk level and guide the doctor to perform other tests or procedures.
The following are some of the blood tests that may be performed:
- Enzymes & Protein Tests – Levels of Troponin T, Creatine Kinase, and Lactate Dehydrogense can be measured. When the heart is damaged from coronary disease, muscle cells are damaged and release enzymes into the bloodstream. Levels of these enzymes can be measured indicating the presence and possible extent of damage caused by coronary artery disease.
- Lipid Blood Tests – While not a specific test for coronary artery disease, abnormal levels of total cholesterol levels are directly linked to risk of coronary artery disease. Total cholesterol and the measurement of High-density lipoprotein (“good”), low-density lipoprotein (“bad”) and triglycerides as independent indices can help in the calculation of your risk of coronary artery disease.
- C-Reactive Protein Testing – Like lipid blood testing this test is used to help identify your risk for cardiovascular disease. C-Reactive proteins are found in the blood stream and are indicators of inflammation. This inflammation can be a result of initial damage from cardiac disease or the progression of damage.
- EKG-Electrocardiograms – This device uses electrodes attached to the chest, arms and legs to measure the electrical activity of the heart. This includes the speed of the heart rate, and the strength and timing of the electric signals as they pass through the heart. When all the measurements are combined they can suggest or indicate the presence of coronary artery disease. An ongoing or previous heart attack can also be identified.
- Chest X-Ray – a picture of the organs and structures inside the chest, including your heart, lungs, and blood vessels.
- Echocardiography – This is a test that utilizes sound waves to evaluate the structures of the chest cavity. An echo can also give information regaurding the function of the heart and the structures inside the heart, such as the contractility of the heart and if the valves of the heart are functioning appropriately.
- Exercise Stress Test – During this test the patient is asked to walk on a treadmill or ride a stationary bicycle while being monitored by an EKG machine and a technician. As the patient exercises the patient is monitored for the following: changes in pulse rate, changes in the electrical pattern of the heart on the EKG, changes in blood pressure, and symptoms like shortness of breath and chest pain. Abnormal changes may be an indication of underlying CAD. If the patient is unable to physically perform the exercise certain medications may be given to stress the heart similarly to exercise. The addition of an echocardiogram or nuclear imaging may be utilized for a more specific identification of areas of the heart that are not receiving adequate blood flow during exercise.
- Electron-Beam Computed Tomography (EBCT) – Two other test that are being used in the screening process are ct scans and MRA’s. These test are gaining usefulness as screening tools even though they are not as specific as a catheterization, they are they can be useful in detecting the presence of coronary artery disease.
- CT scan – Computerized tomography (CT), such as electron beam computerized tomography (EBCT) or a CT coronary angiogram, can isolate the larger coronary arteries and detect calcium within the arteries. A dye can also be injected during the procedure to provide an angiogram of the coronaries. While not as high quality as a catheterization, this can give the doctor a rough idea of the patient’s coronary status without going through an invasive procedure.
- Magnetic resonance angiogram (MRA) – This procedure provides the same type of images as the above ct scans but utilizes magnetic technologies and the use of dye, avoiding exposure to radiation.
- Coronary Angiography and Cardiac Catheterization- If your doctor finds that you are at risk for coronary artery disease they may decide to perform a coronary catheterization and coronary angiogram. During this a procedure a catheter is inserted into the femoral artery in the groin and fed up to the heart and into the coronary arteries. Once in the coronary artery a dye is injected and x-rays are taken. The resulting image is an outline of the coronary artery. Narrowed areas are easily identified with this technique. Once blockages are identified the doctor has many choices about how to proceed.
What Are the Treatments for Coronary Artery Disease?
There are multiple treatment options for CAD. Your options are based on your individual situation and disease state. Possible options include: Lifestyle changes, medicines, angioplasty, stenting, or coronary artery bypass grafting.
- Lifestyle Changes. A change to a healthier lifestyle can influence the health of your arteries significantly. These changes include:
- Stop smoking/ avoid second hand smoke
- Regular exercise
- Maintain a healthy weight
- Reduce high blood pressure
- Reduce high cholesterol
- Eating a healthy diet
- Decreasing stress levels
- Medicines – There are multiple medications that can be used to treat coronary artery disease. The medications all work to achieve certain goals. These include: Lowering high blood pressure, Optimizing cholesterol levels, preventing blood clots, Decrease the workload of the heart, and decrease the risk of heart attacks or sudden death. While all medications have risks and potential side effects, the benefits are often more beneficial.
- Aspirin Therapy – When taken appropriately aspirin can prevent blood clots decrease the risk of heart attacks and decrease the risk of stroke.
- Beta blockers – This is a class of drugs that can decrease the heart’s rate, and the heart’s demand for oxygen. Beta blockers also have the added benefit of reducing the chance of heart attack if the patient has had a prior heart attack.
- Angiotensin – converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) – These two classes of drugs work to decrease blood pressure by causing the arteries to dilate. This then reduces the workload of the heart. This decrease the progression of coronary disease and heart failure. If you’ve had a heart attack, these drugs can reduce the risk of future attacks.
- Calcium channel blockers – These medications work by relaxing muscles that surround your coronary arteries and cause the vessels to dilate, increasing blood flow to your heart. They also control high blood pressure.
- Nitroglycerin. This drug works by dilating the coronary arteries. This can help control chest pain and reduce your heart’s demand for blood.
- PLAVIX – (Clopidogrel) This drug is in a class known as anti-platelet drugs. The drug works by inhibiting the formation of blood clots. This helps in the prevention of heart attacks and strokes that occur from blood clots.
- Cholesterol-modifying medications – This group of medications main objective is to decrease the amount of cholesterol in the blood. By decreasing low-density lipoprotein (LDL, or “bad”) cholesterol and boosting your high-density lipoprotein (HDL, or “good”) cholesterol, you decrease your risk of developing or progressing coronary disease. The different classes of these drugs include statins, niacin, fibrates and bile acid sequestrants. Of these drugs the statins are the first line of medications that have been shown to decrease LDL cholesterol and decrease the incidence of cardiovascular events.
- Catheter Based Procedures – If the coronary disease becomes advanced enough, a more aggressive approach to treatment may become necessary. After a coronary angiogram is performed and blockages are identified your cardiologist may perform a coronary angioplasty if they feel it appropriate. An angioplasty is where a small catheter is advanced through the narrowed coronary artery and a small balloon is inflated. This balloon pushes the plaque against the wall of the artery which widens the opening in the artery allowing more blood flow. In some instances the cardiologist may decide to place a stent in the artery to help keep the plaque from re-occluding the artery.