Coronary artery disease (CAD) is a chronic disease in which the coronary arteries are hardened and narrowed (atherosclerosis). The coronary arteries carry oxygen-rich blood to the heart. When they are diseased, the heart is at risk of not receiving the oxygen-rich blood that it needs in order to function.

CAD develops gradually. First, fatty plaque narrows the coronary arteries. Next, the plaque calcifies, causing the arteries to become harder and stiffer. Untreated, CAD usually continues to worsen and can eventually lead to a heart attack or even cardiac arrest (in which the heart stops beating).

Many CAD patients have symptoms such as chest pain (angina) and fatigue. Other patients have no warning signs at all.

Strategies to help reduce risk factors for CAD include the following:

• Learning your family medical history
• Eating a heart-healthy diet
• Improving your cholesterol ratio
• Controlling homocysteine levels
• Exercising regularly
• Controlling diabetes
• Controlling high blood pressure (hypertension)
• Achieving and maintaining a healthy weight
• Managing your stress
• Quitting smoking (or not starting to smoke)
• Controlling chronic depression

The above strategies could also help slow the progression of CAD if it has already developed.

Treatment options for CAD include medication, balloon angioplasty (with or without stenting) and either traditional bypass surgery or less invasive surgeries such as MIDCAB and OPCRES.

What is coronary artery disease?
Coronary artery disease (CAD) is a chronic disease in which the coronary arteries are hardened and narrowed (atherosclerosis). It is also referred to as coronary heart disease.

CAD patients tend to have periodic episodes where the heart is not receiving enough oxygen-rich blood (cardiac ischemia). Some patients feel no symptoms during these episodes (silent ischemia), while others may experience significant chest pain, pressure or discomfort (angina). If an episode of cardiac ischemia is severe or lengthy, it could trigger cardiac arrest (in which the heart stops beating) or congestive heart failure.

CAD is the leading cause of heart attacks and the most common form of cardiovascular disease. About 84 percent of people who die as a result of CAD are 65 or older. In 50 percent of men and 63 percent of women who die suddenly from CAD, there were no previous symptoms. Most recent statistics also show CAD as the leading cause of premature and permanent disability among workers.

What causes coronary artery disease?
Risk factors for heart disease are thos ehabits and characteristics that make you more prone to coronary artery disease and heart attacks. It is important to realize how your lifestyle may contribute to heart disease. It is important to control and reduce those risk factors that contribute to the disease process.

Major Risk Factors:

• Family history of coronary artery disease
• Cigarette smoking
• High blood pressure
• Increased amount of cholesterol in the blood.

Other Risk Factors:

• Sex (males are more prone to heart disease than females)
• Obesity
• Age
• Diabetes
• High triglycerides (increased fats) in the blood
• Lack of regular exercise
• Stress

What are the symptoms of coronary artery disease?
Symptoms typically associated with CAD include chest pain (angina) and shortness of breath, especially after stress or exercise. Women with CAD may experience breast pain or a feeling of indigestion in the upper abdomen.

However, about 25 to 30 percent of patients have no symptoms, despite the presence of CAD. They may have silent ischemia, or be unaware of potentially dangerous abnormal heart rhythms (arrhythmias). The absence of chest pain or other common symptoms can also set the stage for a heart attack that occurs without warning.

How is coronary artery disease diagnosed?
Patients who do experience one or more symptoms should consult with their physician as soon as possible. The physician will obtain a medical history and give a complete physical examination, which will include a coronary risk profile. A number of diagnostic tests may then be ordered to help the physician to identify blockages in the arteries before more serious complications arise. Noninvasive tests include the following:

• Physical examination by the physician. This includes a complete medical history and coronary risk profile.
• Blood tests. These tests can measure risk factors for CAD, such as cholesterol levels, homocysteine levels, C-reactive protein levels and blood clotting factors.
• Electrocardiogram (EKG). An EKG is a recording of the heart's electrical activity as a graph, or series of wave lines, on a moving strip of paper or video monitor. The highly sensitive electrocardiograph machine helps detect heart irregularities, disease and damage by measuring the heart's rhythms and electrical impulses.
• Exercise stress test. An EKG is performed while the patient exercises in a controlled manner on a treadmill or stationary bicycle at varied speeds and elevations. The reaction of the heart under exertion can be measured and evaluated. This allows the physician to evaluate the performance of the heart under strenuous conditions and the presence of CAD.
• Echocardiogram of the heart and major arteries. This test uses sound waves to track the structure and function of the heart. A moving image of the patient's beating heart is played on a video screen, where a physician can study the heart's thickness, size and function. The image also shows the motion pattern and structure of the four heart valves, revealing any potential leakage (regurgitation) or narrowing (stenosis). During this test, a Doppler ultrasound may also be done to evaluate blood flow through the heart. A Doppler ultrasound may be combined with an exercise stress test to evaluate heart function.
• Myocardial perfusion imaging. Any of a number of tests (also known as scans) that use harmless injections of radionuclide substances (e.g., thallium or technetium) to create images of the heart. This procedure may be combined with an exercise stress test to identify and localize blockages in the coronary arteries.

A coronary angiogram is a minimally invasive test that may be done if any of the above tests are abnormal, or if the patient has a history of heart-related problems. The coronary angiogram is basically a strategy for visualizing the coronary arteries. It involves the insertion of a catheter into a major blood vessel and the injection of a dye (contrast medium) to create a high-quality image of the heart and coronary arteries.

• Beta blockers. Medications that reduce the workload of the heart by blocking certain chemicals from binding to beta receptors in the heart.
• Nitrates. Medications that work directly on the blood vessels, causing them to relax and allowing more oxygen-rich blood to reach the heart.
• Calcium channel blockers (calcium antagonists). Medications that increase blood flow through the heart and may reduce the workload of the heart by blocking calcium ions from signaling the blood vessels to constrict or tighten.
• Antiplatelets (e.g., aspirin), clopidogrel). Medications that inhibit the formation of blood clots by decreasing the ability of platelets (microscopic particles found in the blood) to bind together and form a blood clot.
• Statins. A type of cholesterol-reducing drug that lowers the levels of fats (lipids) in the blood, including cholesterol and triglycerides. Statins work by blocking the production of specific enzymes used by the body to make cholesterol. They are effective in lowering blood fat levels in patients with of high cholesterol (hypercholesterolemia) and are therefore helpful in the prevention of coronary, cerebrovascular and peripheral vascular disease.
• Other drugs interfering with the absorption of cholesterol from the intestinal tract (e.g., ezetimibe, fibrates, bile acid resins).

• Balloon angioplasty. A procedure in which the physician uses a balloon-tipped catheter to push plaque back against the artery wall to allow for better blood flow in the artery. During this procedure, the physician may also do an atherectomy (in which the physician destroys plaque in the arteries by cutting it away) and/or stenting (in which a metal tube is inserted into an artery to help it open, permitting adequate blood flow).
• Coronary artery bypass graft (CABG). A surgery that increases blood flow to the heart by creating a detour and re-routing the blood flow around the blocked portion of the artery. A section of a blood vessel from another part of the body (e.g., the leg or chest) is relocated and grafted above and below the damaged portion of the coronary artery to form an open channel around the blockage.

• Learning your family medical history. A patient’s family medical history can greatly increase (or decrease) the risk of the patient developing certain medical conditions, including coronary artery disease. Some patients prefer to develop their own medical family tree and bring it with them to their doctor appointment. A complete family tree traces the medical history of an individual (and his or her spouse, if applicable), through at least several generations.
• Eating a heart-healthy diet. Modern research has consistently supported the idea that the health of people’s bodies is largely determined by what they choose to eat. While certain vitamins and minerals have been shown to be helpful to heart health, fats and oils such as saturated fat and tropical oils (palm and coconut oil) have been shown to be particularly harmful, because they can speed up the development of coronary artery disease, atherosclerosis and obesity.
• Improving your cholesterol ratio. A person's total cholesterol level (which includes LDL cholesterol, HDL cholesterol and triglycerides) should be no more than 200 milligrams per deciliter and no more than five times the HDL level. Key strategies for reducing levels of total cholesterol, LDL cholesterol and triglycerides are to eat a heart-healthy diet and to exercise regularly. If these strategies do not reduce total cholesterol levels, a physician may prescribe cholesterol-reducing drugs. Strategies for increasing levels of HDL cholesterol include eating monounsaturated fats in moderation, decreasing the amount of saturated fat, limiting alcohol use and starting an exercise program.
• Controlling homocysteine levels. High homocysteine levels have been linked to damage of the arteries, which may increase the risk of heart attack, stroke or other cardiovascular problems. Researchers are currently trying to determine whether high homocysteine levels are an actual cause of those conditions, or are simply associated with them for some other reason. A heart-healthy diet, providing recommended allowances of three important B-vitamins (vitamin B-6, B-12 and folic acid), can help maintain healthy body levels of homocysteine. Food sources high in these B-vitamins include fruits, vegetables, whole grains and fortified grain products. Experts do not currently advocate routine intake of supplements; folate supplements, for example, may mask a true vitamin B-12 deficiency. Individuals should speak with their physician as to whether a particular supplement is indicated.
• Exercising regularly. Exercise can be an excellent tool for both preventing heart disease and improving quality of life for heart patients. Physically, it can slow or even reverse the process of atherosclerosis, as well as lower blood pressure and reduce cholesterol levels. Emotionally, it can reduce levels of stress and depression.
• Controlling diabetes. Persons with diabetes may be more likely to develop heart-related diseases. Preventive care is crucial to the overall health and heart function of diabetic patients. To this end, the control of blood sugar levels with diet and/or medication has an important role in altering the process of atherosclerosis.
• Controlling high blood pressure (hypertension). Individuals with high blood pressure are at greater risk of cardiovascular problems resulting from CAD. Hypertension can be controlled through taking blood pressure medications, self-monitoring, eating a heart-healthy, low-salt diet and engaging in regular exercise. People are also encouraged to have regular check-ups with their physician.
• Controlling weight. Obesity and being overweight are major risk factors for a host of serious health conditions, including coronary artery disease, high blood pressure, diabetes, heart attack and stroke. Some weight control methods include limiting fat in the diet, increasing activity levels, counseling, medication and surgical interventions.
• Managing your stress. Some people react to stress in unhealthy ways, such as overeating and smoking. Chronic stress by itself may be a direct contributor to poor heart health because it produces increases in blood pressure that could become permanent.
• Quitting smoking (or not starting to smoke). Tobacco smoking is a major cause of coronary artery disease and cardiac arrest. The CDC also states that both middle-aged males and female smokers triple their risk of death to heart disease.
• Controlling chronic depression. Depression has been linked with a higher risk of developing high blood pressure, heart disease and having a heart attack. These strategies may help to preserve health and prolong life, and are particularly important for those of advanced age and those with a family history of heart disease. Even someone who has suffered a cardiac event (e.g., heart attack) can reduce the risk of having another one by changing unhealthy behaviors and stopping all high-risk activities.

• High-density lipoproteins (HDL), which are associated with “good” cholesterol.
• Low-density lipoproteins (LDL), associated with “bad” cholesterol.
• Very-low-density lipoproteins (VLDL), which are associated with “very bad” cholesterol.
• Chylomicrons, which only carry a small percentage of cholesterol. Chylomicrons are mostly rich in another type of fat (lipid) called triglycerides.

• Apolipoprotein A1 (APOA1) The body’s blueprint for creating apolipoprotein A1, which is packaged with proteins to form HDL (good cholesterol). A poorly functioning APOA1 means low levels of HDL, which can lead to heart attack and stroke.
• CETP. The body’s blueprint for a protein that helps break down HDL. Variants of this gene cause the breakdown of HDL to occur less efficiently, resulting in increased HDL levels in the blood. While increased levels of HDL generally decrease heart disease risk, it is currently unknown to what extent CETP influences the risk of disease in the general population.
• LDL Receptor (LDLR). The body’s blueprint for removing LDLs from the blood stream. An impaired or mutated LDLR means that LDL is not removed from the blood effectively, resulting in high LDL levels. Scientists have found more than 350 variants of this gene. About one in 500 people have the variant associated with familial hypercholesterolemia (FH). FH is the most widespread inherited cholesterol disorder, with affected individuals having cholesterol levels as high as 550 milligrams per deciliter. This is almost four times the desired level, thereby significantly increasing the risk for early heart attack, regardless of the presence of other risk factors.
• Apolipoprotein E (APOE). The body's blueprint for creating apolipoprotein E, which is involved in the removal of LDL from blood. Variations of this gene can cause high levels of LDL to occur, especially in people who eat a high-fat, high-cholesterol diet.
• Apo(a) . A gene that creates the Apo(a) protein, which combines with LDL cholesterol to forms Lp(a), a new protein that affects the ability of the blood to clot (coagulation). High Lp(a) levels in the blood have been linked to the development of CAD and to increased heart attack risk.

• Integrin (ITGB3) . Another gene that affects coagulation, variations of ITGB3 have been found in a significant number of CAD patients.
• Elastin (ELN) . The blueprint for a protein component of the elastic fibers found throughout the body. These fibers affect to elasticity of body tissue such as blood vessels. For instance, arteries deficient in elastin will often take a shape that inhibits the flow of blood and contributes to CAD. Elastin is lost as a part of the aging process.
• PTGIS. The blueprint for a protein (prostacyclin) that coats the inner layers of blood vessels, keeping blood from sticking and forming clots.
• ACE. While this gene is one of the most studied in regard to CAD, very little is known about its effect on heart disease. ACE is the blueprint for a protein that affects the heart, kidneys and arterial walls.