Dr. MJ Bazos MD,
Coronary Heart Disease
Some 7 million Americans suffer from coronary
artery disease (CAD), the most common form of heart disease. This type of heart
disease is caused by a narrowing of the coronary arteries that feed the heart.
CAD is the number one killer of both
men and women in the U.S. Each year, more than 500,000 Americans die of heart
attacks caused by CAD.
Many of these
deaths could be prevented because CAD is related to certain aspects of
lifestyle. Risk factors for CAD include high blood pressure, high blood
cholesterol, smoking, obesity, and physical inactivity—all of which can be
controlled. Although medical treatments for heart disease have come a long way,
controlling risk factors remains the key to preventing illness and death from
Who Is at Risk for CAD?
Risk factors are conditions that
increase your risk of developing heart disease. Some can be changed and some
cannot. Although these factors each increase the risk of CAD, they do not
describe all the causes of coronary heart disease; even with none of these risk
factors, you might still develop CAD.
* High blood pressure
* High blood cholesterol
* Physical inactivity
* Heredity (family history of CAD)
What Is CAD?
Like any muscle, the heart needs a
constant supply of oxygen and nutrients that are carried to it by the blood in
the coronary arteries. When the coronary arteries become narrowed or clogged and
cannot supply enough blood to the heart, the result is CAD. If not enough
oxygen-carrying blood reaches the heart, the heart may respond with pain called
angina. The pain is usually felt in the chest or sometimes in the left arm and
shoulder. (However, the same inadequate blood supply may cause no symptoms, a
condition called silent angina.)
the blood supply is cut off completely, the result is a heart attack. The part
of the heart that does not receive oxygen begins to die, and some of the heart
muscle may be permanently damaged.
What Causes CAD?
CAD is caused by a thickening of the
inside walls of the coronary arteries. This thickening, called atherosclerosis,
narrows the space through which blood can flow, decreasing and sometimes
completely cutting off the supply of oxygen and nutrients to the heart.
Atherosclerosis usually occurs when a
person has high levels of cholesterol, a fat-like substance, in the blood.
Cholesterol and fat, circulating in the blood, build up on the walls of the
arteries. The buildup narrows the arteries and can slow or block the flow of
blood. When the level of cholesterol in the blood is high, there is a greater
chance that it will be deposited onto the artery walls. This process begins in
most people during childhood and the teenage years, and worsens as they get
In addition to high blood
cholesterol, high blood pressure and smoking also contribute to CAD. On the
average, each of these doubles your chance of developing heart disease.
Therefore, a person who has all three risk factors is eight times more likely to
develop heart disease than someone who has none. Obesity and physical inactivity
are other factors that can lead to CAD. Overweight increases the likelihood of
developing high blood cholesterol and high blood pressure, and physical
inactivity increases the risk of heart attack. Regular exercise, good nutrition,
and smoking cessation are key to controlling the risk factors for CAD.
What Are the Symptoms of CAD?
Chest pain (angina) or shortness of
breath may be the earliest signs of CAD. A person may feel heaviness, tightness,
pain, burning, pressure, or squeezing, usually behind the breastbone but
sometimes also in the arms, neck, or jaws. These signs usually bring the patient
to a doctor for the first time. Nevertheless, some people have heart attacks
without ever having any of these symptoms.
It is important to know that there is
a wide range of severity for CAD. Some people have no symptoms at all, some have
mild intermittent chest pain, and some have more pronounced and steady pain.
Still others have CAD that is severe enough to make normal everyday activities
Because CAD varies so much
from one person to another, the way a doctor diagnoses and treats CAD will also
vary a lot. The following descriptions are general guidelines to some tests and
treatments that may or may not be used, depending on the individual case.
Are There Tests for CAD?
There is no one simple test—some
or all of the following procedures may be needed. These diagnostic procedures
are used to establish CAD, to determine its extent and severity, and to rule out
other possible causes of the symptoms.
After taking a careful medical history
and doing a physical examination, the doctor may use some tests to see how
advanced the CAD is. The only certain way to diagnose and assess the extent of
CAD is coronary angiography (see below); other tests can indicate a problem but
do not show exactly where it is.
examination for CAD may include the tests that follow below.
An electrocardiogram (ECG or EKG)
is a graphic record of the electrical activity of the heart as it contracts and
rests. Abnormal heartbeats and some areas of damage, inadequate blood flow, and
heart enlargement can be detected on the records.
A stress test (also called a treadmill
test or exercise ECG) is used to record the heartbeat during exercise. This
is done because some heart problems only show up when the heart is working hard.
In the test, an ECG is done before, during, and after exercising on a treadmill;
breathing rate and blood pressure may be measured as well. Exercise tests are
useful but are not completely reliable; false positives (showing a problem where
none exists) and false negatives (showing no problem when something is wrong)
are fairly common.
is sometimes used to show damaged areas of the heart and expose problems with
the heart's pumping action. A small amount of radioactive material is injected
into a vein, usually in the arm. A scanning camera records the nuclear material
that is taken up by heart muscle (healthy areas) or not taken up (damaged
Coronary angiography (or
arteriography) is a test used to explore the coronary arteries. A fine tube
(catheter) is put into an artery of an arm or leg and passed through the tube
into the arteries of the heart. The heart and blood vessels are then filmed
while the heart pumps. The picture that is seen, called an angiogram or
arteriogram, will show problems such as a blockage caused by atherosclerosis.
How Is CAD Treated?
CAD is treated in a number of ways,
depending on the seriousness of the disease. For many people, CAD is managed
with lifestyle changes and medications. Others with severe CAD may need surgery.
In any case, once CAD develops, it requires lifelong management.
What Kind of Lifestyle Changes Can
Help a Person With CAD?
advances have been made in treating CAD, changing one's habits remains the
single most effective way to stop the disease from progressing.
If you know that you have CAD,
changing your diet to one low in fat, especially saturated fat, and cholesterol
will help reduce high blood cholesterol, a primary cause of atherosclerosis. In
fact, it is even more important to keep your cholesterol low after a heart
attack to help lower your risk of having another one. Eating less fat should
also help you lose weight. If you are overweight, losing weight can help lower
blood cholesterol and is the most effective lifestyle way to reduce high blood
pressure, another risk factor for atherosclerosis and heart disease.
People with CAD can also benefit from
exercise. Recent research has shown that even moderate amounts of physical
activity are associated with lower death rates from CAD. However, people with
severe CAD may have to restrict their exercise somewhat. If you have CAD, check
with your doctor to find out what kinds of exercise are best for you.
Smoking is one of the three major risk
factors for CAD. Quitting smoking dramatically lowers the risk of a heart attack
and also reduces the risk of a second heart attack in people who have already
What Medications Are Used
to Treat Coronary Heart Disease?
Medications are prescribed according
to the nature of the patient's CAD and other problems. The symptoms of angina
can generally be controlled by "beta-blocker" drugs that decrease the workload
on the heart, by nitroglycerine and other "nitrates" and by "calcium-channel
blockers" that relax the arteries, and by other classes of drugs. The tendency
to form clots is reduced by aspirin or by other platelet inhibitory and
anticoagulant drugs. Beta-blockers are given to decrease the recurrence of heart
attack. For those with elevated blood cholesterol that is unresponsive to
dietary and weight loss measures, cholesterol-lowering drugs may be prescribed,
such as lovastatin, colestipol, cholestyramine, gemfibrozil, and niacin.
Impaired pumping function of the heart may be treated with digitalis drugs or
ACE inhibitors. If there is high blood pressure or fluid retention, these
conditions are also treated.
doctor which medication you are taking, what it does, and whether there are any
side effects. Knowing more about this will help you stick to the schedule that
has been prescribed for you.
Types of Surgery Are Used to Treat CAD?
Many patients can control CAD with
lifestyle changes and medication. Surgery may be recommended for patients who
continue to have frequent or disabling angina despite the use of medications, or
people who are found to have severe blockages in their coronary arteries.
Coronary angioplasty or balloon
angioplasty begins with a procedure similar to that described under angiography.
However, the catheter positioned in the narrowed coronary artery has a tiny
balloon at its tip. The balloon is inflated and deflated to stretch or break
open the narrowing and improve the passage for blood flow. The balloon-tipped
catheter is then removed.
speaking, angioplasty is not surgery. It is done while the patient is awake and
may last 1 to 2 hours. If angioplasty does not widen the artery or if
complications occur, bypass surgery may be needed.
In a coronary artery bypass operation,
a blood vessel, usually taken from the leg or chest, is grafted onto the blocked
artery, bypassing the blocked area. If more than one artery is blocked, a bypass
can be done on each. The blood can then go around the obstruction to supply the
heart with enough blood to relieve chest pain.
Bypass surgery relieves symptoms of
heart disease but does not cure it. Usually you will need to make a number of
changes in your lifestyle after the operation. If your normal lifestyle includes
smoking, a high-fat diet, or no exercise, changes are advised.
Several experimental catheter-surgical
procedures for unblocking coronary arteries are under study; their safety and
effectiveness have not yet been established. They include:
•Atherectomy, a procedure in which
surgeons shave off thin strips of the plaque blocking the artery and remove
•Laser angioplasty; instead of using a
balloon to open up the blocked artery, doctors insert a catheter with a laser
tip that burns or breaks down the plaque.
•Insertion of a stent, a metal coil that
can be permanently implanted in a narrowed part of an artery to keep it propped