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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 coronary artery
disease - the number one killer of both men and women
in the US.
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:
• Left circumflex artery (LCX)
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 are the risk factors for coronary artery
disease?
Risk factors for CAD often include:
* high LDL cholesterol, high triglycerides 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 coronary heart disease 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 in that involved area of the heart, and
the heart muscle begins to die. Some people may have
a heart attack and never recognize the 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
* weakness and fatigue
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 (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-ray images are taken after
a contrast agent is injected into a coronary 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 heart 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
• controlling risk factors (the most effective
way to stop the progression of CHD)
» 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 or percutaneous coronary
intervention (PCI) - with this procedure, a catheter
inserted into the femoral or radial artery 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 is 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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