What are the coronary arteries?

Like all other tissues in the body, the heart muscle needs oxygen-rich blood to function, and oxygen-depleted blood must be carried away. Coronary arteries supply blood to the heart muscle.

The two main coronary arteries are the left and right coronary arteries. The left coronary artery (LCA) divides into the left anterior descending and the circumflex arteries. The circumflex artery encircles the heart muscle and supplies blood to the back of the heart and the left anterior descending artery supplies blood to front of the heart. These arteries and their branches carry blood to the heart ventricles and left atrium.

The right coronary artery (RCA) divides into the right posterior descending artery and an acute marginal branch. These arteries and their branches supply blood to the heart ventricles, right atrium, and sinoatrial node (cluster of cells in the right atrial wall that regulate the heart's rhythmic rate).

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 form of coronary artery disease.

What is coronary artery disease?

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 life. This thickening, called atherosclerosis, narrows the arteries and can decrease or block the flow of blood to the heart.

Over 12 million Americans suffer from coronary heart disease. It is the number one killer of both men and women in the US.

What are the risk factors for coronary artery disease?

Risk factors for CAD often include:

• high blood cholesterol
• high blood pressure (hypertension)
• physical inactivity
• smoking
• obesity
• diabetes

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

What are the symptoms of coronary artery disease?

The symptoms of coronary artery disease will depend on the severity of the disease. Some persons with CAD have no symptoms, some have episodes of mild chest pain, 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 may be damaged. Some persons may have a heart attack and never present any symptoms. This is called a "silent" heart attack.

When symptoms are present, each person may experience them differently. Symptoms of coronary artery disease 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 and/or nausea

How is coronary artery disease diagnosed?

In addition to a complete medical history and physical examination, diagnostic procedures for coronary artery disease 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 (also called treadmill or exercise ECG) - a test that is given while a patient walks on a treadmill to monitor the heart during exercise. Respiratory rate and blood pressure 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.
• coronary arteriogram (or angiogram) - 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.

How is coronary artery disease treated?

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
  • changing to a low-fat diet
  • losing weight (if overweight)
  • establishing and maintaining an appropriate exercise program
  • quitting smoking
  • controlling blood sugar if you have diabetes
  • reducing blood pressure
  
  

• medications - statin medications that reduce cholesterol levels, prevent the progression of coronary artery disease, and reduce the incidence of heart attacks. Other medications may be used to prevent angina or treat other complications of coronary artery disease.

• 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.
  • atherectomy - the blocked area inside the artery is "shaved" away by a tiny device on the end of a catheter.
  • coronary artery stent - a tiny titanium coil is expanded inside the blocked artery to open the blocked area and is left in place to keep the artery open. Many stents used today are coated with medications that significantly reduce the chance that a new blockage will form at the site.
• coronary artery bypass - a surgical procedure in which small portions of veins or arteries are taken from one part of the body and transplanted into the heart to bypass clogged coronary arteries in the heart.