Coronary Heart Disease

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What are the coronary arteries?

Coronary arteries supply blood to the heart muscle. Like all other tissues in the body, the heart muscle needs oxygen-rich blood to function, and oxygen-depleted blood must be carried away. The coronary arteries consist of two main arteries: the right and left coronary arteries. The left coronary artery system branches into the circumflex artery and the left anterior descending artery.

What are the different coronary arteries?

The two main coronary arteries are the left and right coronary arteries. The left coronary artery (LCA), which divides into the left anterior descending artery and the circumflex branch, supplies blood to the left ventricle and left atrium. The right coronary artery (RCA), which divides into the right posterior descending and acute marginal arteries, supplies blood to the right ventricle, right atrium, and sinoatrial node (cluster of cells in the right atrial wall that regulates the heart's rhythmic rate), and atrioventricular node (AV node, a cluster of cells between the atria and ventricles that regulate the electrical current).

Additional arteries branch off the two main coronary arteries to supply the heart muscle with blood. These include the following:

• circumflex artery (Cx)
  The circumflex artery branches off the left coronary artery and encircles the heart muscle. This artery supplies blood to the lateral side and back of the heart.
• left anterior descending artery (LAD)
  The left anterior descending artery branches off the left coronary artery and supplies blood to the front of the left side of the heart.

Smaller branches of the coronary arteries include: acute marginal, posterior descending (PDA), obtuse marginal (OM), septal perforator, and diagonals.

Why are the coronary arteries important?

Since coronary arteries deliver blood to the heart muscle, any coronary artery disorder or disease can have serious implications by reducing the flow of oxygen and nutrients to the heart, which may lead to a heart attack and possibly death. Atherosclerosis (a build-up of plaque in the inner lining of an artery causing it to narrow or become blocked) is the most common cause of heart disease.

What is coronary artery disease?

Coronary heart disease, or coronary artery disease (CAD), is characterized by the accumulation of fatty deposits along the innermost layer of the coronary arteries. The fatty deposits may develop in childhood and continue to thicken and enlarge throughout the life span. This thickening, called atherosclerosis, narrows the arteries and can decrease or block the flow of blood to the heart.

Nearly 13 million Americans suffer from CAD - the number one killer of both men and women in the US.

What are the risk factors for coronary heart disease?

Risk factors for CAD often include:

• high LDL cholesterol, high triglyceride levels and reduced HDL cholesterol 
• high blood pressure (hypertension)
• physical inactivity
• smoking
• obesity
• high saturated fat diet

Controlling risk factors is the key to preventing illness and death from CAD.

What are the symptoms of coronary artery disease?

The symptoms of CAD will depend on the severity of the disease. Some persons with CAD have no symptoms, some have episodes of mild chest pain or angina, and some have more severe chest pain.

If too little oxygenated blood reaches the heart, a person will experience chest pain called angina. When the blood supply is completely cut off, the result is a heart attack, and the heart muscle begins to die. Some persons may have a heart attack and never recognize symptoms. This is called a "silent" heart attack.

When symptoms are present, each person may experience them differently. Symptoms of CAD may include:

• heaviness, tightness, pressure, and/or pain in the chest - behind the breastbone
• pain radiating in the arms, shoulders, jaw, neck, and/or back
• shortness of breath
• weakness and fatigue

How is coronary artery disease diagnosed?

In addition to a complete medical history and physical examination, diagnostic procedures for CAD may include any, or a combination of, the following:

• electrocardiogram (ECG or EKG) - a test that records the electrical activity of the heart, shows abnormal rhythms (arrhythmias or dysrhythmias), and detects heart muscle damage.
• stress test (usually with ECG; also called treadmill or exercise ECG) - a test that is given while a patient walks on a treadmill to monitor the heart during exercise. Breathing and blood pressure rates are also monitored. A stress test may be used to detect coronary artery disease, and/or to determine safe levels of exercise following a heart attack or heart surgery.
• cardiac catheterization - with this procedure, x-rays are taken after a contrast agent is injected into an artery - to locate the narrowing, occlusions, and other abnormalities of specific arteries.
• nuclear scanning - radioactive material is injected into a vein and then is observed using a camera as it is taken up by the heart muscle. This indicates the healthy and damaged areas of the heart.

Treatment for coronary artery disease:

Specific treatment will be determined by your physician based on:

• your age, overall health, and medical history
• extent of the disease
• your tolerance for specific medications, procedures, or therapies
• expectations for the course of the disease
• your opinion or preference

Treatment may include:

• controlling risk factors (the most effective way to stop the progression of CAD)
  • changing to a low-fat diet
  • losing weight (if overweight)
  • establishing and maintaining an appropriate exercise program
  • quitting smoking
  • controlling blood sugar if diabetic
• medication
• coronary angioplasty - with this procedure, a catheter is used to create a bigger opening in the vessel to increase blood flow. Although angioplasty is performed in other blood vessels, Percutaneous Transluminal Coronary Angioplasty (PTCA) refers to angioplasty in the coronary arteries to permit more blood flow into the heart. There are several types of PTCA procedures, including:
  • balloon angioplasty - a small balloon is inflated inside the blocked artery to open the blocked area.
  • coronary artery stent - a tiny coil is expanded inside the blocked artery to open the blocked area and is left in place to keep the artery open.
  • atherectomy - the blocked area inside the artery is cut away by a tiny device on the end of a catheter.
  • laser angioplasty - a laser used to "vaporize" the blockage in the artery.
• coronary artery bypass - Most commonly referred to as simply "bypass surgery," this surgery is often performed in people who have angina (chest pain) and coronary artery disease (where plaque has built up in the arteries). During the surgery, a bypass is created by grafting a piece of a vein above and below the blocked area of a coronary artery, enabling blood to flow around the obstruction. Veins are usually taken from the leg, but arteries from the chest may also be used to create a bypass graft.

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