What Is Atherosclerosis?
Atherosclerosis (ath-er-o-skler-O-sis) is a disease
in which plaque (plak) builds up on the insides of your arteries.
Arteries are blood vessels that carry oxygen-rich blood to your heart and other
parts of your body.
Plaque is made up of fat, cholesterol, calcium, and
other substances found in the blood. Over time, plaque hardens and
narrows your arteries. The flow of oxygen-rich blood to your organs and
other parts of your body is reduced. This can lead to serious problems,
including
heart
attack,
stroke, or even death.
Atherosclerosis
Figure A shows a normal artery with
normal blood flow. Figure B shows an artery with plaque buildup.
Overview
Atherosclerosis can affect any artery in the body,
including arteries in the heart, brain, arms, legs, and pelvis. As a result,
different diseases may develop based on which arteries are affected.
-
Coronary
artery disease (CAD). This is when plaque builds up in the coronary
arteries. These arteries supply oxygen-rich blood to your heart. When blood
flow to your heart is reduced or blocked, it can lead to chest pain and heart
attack. CAD also is called heart disease, and it's the leading cause of death
in the United States.
- Carotid (ka-ROT-id) artery disease. This happens when plaque
builds up in the carotid arteries. These arteries supply oxygen-rich blood to
your brain. When blood flow to your brain is reduced or blocked, it can lead to
stroke.
- Peripheral
arterial disease (PAD). This occurs when plaque builds up in the major
arteries that supply oxygen-rich blood to the legs, arms, and pelvis. When
blood flow to these parts of your body is reduced or blocked, it can lead to
numbness, pain, and sometimes dangerous infections.
Some people with atherosclerosis have no signs or
symptoms. They may not be diagnosed until after a heart attack or stroke.
The main treatment for atherosclerosis is lifestyle
changes. You also may need medicines and medical procedures. These, along with
ongoing medical care, can help you live a healthier life.
The cause of atherosclerosis isnt known.
However, certain conditions may raise your chances of developing it. These
conditions are known as risk factors. You can control some risk factors, such
as lack of physical activity, smoking, and unhealthy eating. Others you
cant control, such as age and family history of heart disease.
Outlook
Better treatments have reduced the number of deaths
from atherosclerosis-related diseases. These treatments also have improved the
quality of life for people with these diseases. Still, the number of people
diagnosed with atherosclerosis remains high.
You may be able to prevent or delay atherosclerosis
and the diseases it can cause, mainly by maintaining a healthy lifestyle. This,
along with ongoing medical care, can help you avoid the problems of
atherosclerosis and live a long, healthy life.
Other Names for Atherosclerosis
- Arteriosclerosis (ar-TER-e-o-skler-o-sis)
- Hardening of the arteries
What Causes Atherosclerosis?
The exact cause of atherosclerosis isn't known.
However, studies show that atherosclerosis is a slow, complex disease that may
start in childhood. It develops faster as you age.
Atherosclerosis may start when certain factors
damage the inner layers of the arteries. These factors include:
When damage occurs, your body starts a healing
process. Fatty tissues release compounds that promote this process. This
healing causes plaque to build up where the arteries are damaged.
Over time, the plaque may crack. Blood cells called
platelets (PLATE-lets) clump together to form blood clots where the cracks are.
This narrows the arteries more and worsens
angina
(chest pain) or causes a
heart
attack.
Researchers continue to look at why atherosclerosis
develops. They hope to find answers to such questions as:
- Why and how do the arteries become damaged?
- How does plaque develop and change over time?
- Why does plaque break open and lead to
clots?
Who Is At Risk for Atherosclerosis?
Coronary
artery disease (atherosclerosis of the coronary arteries) is the leading
cause of death in the United States.
The exact cause of atherosclerosis isn't known.
However, certain traits, conditions, or habits may raise your chance of
developing it. These conditions are known as risk factors. Your chances of
developing atherosclerosis increase with the number of risk factors you have.
You can control most risk factors and help prevent
or delay atherosclerosis. Other risk factors can't be controlled.
Major Risk Factors
-
Unhealthy
blood cholesterol levels. This includes high LDL cholesterol (sometimes
called bad cholesterol) and low HDL cholesterol (sometimes called good
cholesterol).
- High
blood pressure. Blood pressure is considered high if it stays at or above
140/90 mmHg over a period of time.
- Smoking. This can damage and tighten blood
vessels, raise cholesterol levels, and raise blood pressure. Smoking also
doesn't allow enough oxygen to reach the body's tissues.
- Insulin resistance. This condition occurs when
the body can't use its own insulin properly. Insulin is a hormone that helps
move blood sugar into cells where it's used.
- Diabetes. This is a disease in which the bodys blood
sugar level is high because the body doesnt make enough insulin or
doesnt use its insulin properly.
- Overweight
or obesity. Overweight is having extra body weight from muscle, bone, fat,
and/or water. Obesity is having a high amount of extra body fat.
- Lack of physical activity. Lack of activity can
worsen other risk factors for atherosclerosis.
- Age. As you get older, your risk for
atherosclerosis increases. Genetic or lifestyle factors cause plaque to build
in your arteries as you age. By the time you're middle-aged or older, enough
plaque has built up to cause signs or symptoms.
- In men, the risk increases after age 45.
- In women, the risk increases after age 55.
- Family history of early heart disease. Your risk
for atherosclerosis increases if your father or a brother was diagnosed with
heart disease before 55 years of age, or if your mother or a sister was
diagnosed with heart disease before 65 years of age.
Although age and a family history of early heart
disease are risk factors, it doesn't mean that you will develop atherosclerosis
if you have one or both.
Making lifestyle changes and/or taking medicines to
treat other risk factors can often lessen genetic influences and prevent
atherosclerosis from developing, even in older adults.
Emerging Risk Factors
Scientists continue to study other possible risk
factors for atherosclerosis.
High levels of a protein called C-reactive protein
(CRP) in the blood may raise the risk for atherosclerosis and
heart
attack. High levels of CRP are proof of inflammation in the body.
Inflammation is the body's response to injury or infection. Damage to the
arteries' inner walls seems to trigger inflammation and help plaque grow.
People with low CRP levels may get atherosclerosis
at a slower rate than people with high CRP levels. Research is under way to
find out whether reducing inflammation and lowering CRP levels also can reduce
the risk of atherosclerosis.
High levels of fats called triglycerides in the
blood also may raise the risk of atherosclerosis, particularly in women.
Other Factors That Affect Atherosclerosis
Other risk factors also may raise your risk for
developing atherosclerosis. These include:
-
Sleep
apnea. Sleep apnea is a disorder in which your breathing stops or gets very
shallow while you're sleeping. Untreated sleep apnea can raise your chances of
having high blood pressure, diabetes, and even a heart attack or
stroke.
- Stress. Research shows that the most commonly
reported "trigger" for a heart attack is an emotionally upsetting
eventparticularly one involving anger.
- Alcohol. Heavy drinking can damage the heart
muscle and worsen other risk factors for atherosclerosis. Men should have no
more than two drinks containing alcohol a day. Women should have no more than
one drink containing alcohol a day.
What Are the Signs and Symptoms of
Atherosclerosis?
Atherosclerosis usually doesn't cause signs and
symptoms until it severely narrows or totally blocks an artery. Many people
don't know they have the disease until they have a medical emergency, such as a
heart
attack or
stroke.
Some people may have other signs and symptoms of the
disease. These depend on which arteries are severely narrowed or blocked.
The coronary arteries supply oxygen-rich blood to
your heart. When plaque narrows or blocks these arteries (a condition called
coronary
artery disease, or CAD), a common symptom is
angina
(AN-ji-na or an-JI-na).
Angina is chest pain or discomfort that occurs when
your heart muscle doesn't get enough oxygen-rich blood. Angina may feel like
pressure or a squeezing pain in your chest. You also may feel it in your
shoulders, arms, neck, jaw, or back.
This pain tends to get worse with activity and go
away when you rest. Emotional stress also can trigger the pain.
Other symptoms of CAD are shortness of breath and
arrhythmias
(irregular heartbeats).
The carotid arteries supply oxygen-rich blood to
your brain. When plaque narrows or blocks these arteries (a condition called
carotid artery disease), you may have symptoms of a stroke.
These symptoms include sudden numbness, weakness, and dizziness.
Plaque also can build up in the major arteries that
supply oxygen-rich blood to the legs, arms, and pelvis (a condition called
peripheral
arterial disease). When these arteries are narrowed or blocked, it can lead
to numbness, pain, and sometimes dangerous infections.
How Is Atherosclerosis Diagnosed?
Your doctor will diagnose atherosclerosis based
on:
- Your medical and family histories
- Your risk factors
- The results of a physical exam and diagnostic
tests
Specialists Involved
If you have atherosclerosis, a doctor, internist, or
general practitioner may handle your care. Your doctor may send you to other
health care specialists if you need expert care. These specialists may
include:
- A cardiologist (a doctor who specializes in
treating people with heart problems). You may see a cardiologist if you have
coronary
artery disease (CAD).
- A vascular specialist (a doctor who specializes
in treating people with blood vessel problems). You may see a vascular
specialist if you have
peripheral
arterial disease (PAD).
- A neurologist (a doctor who specializes in
treating people with disorders of the nervous system). You may see a
neurologist if you've had a stroke due to
carotid artery disease.
Physical Exam
During the physical exam, your doctor may listen to
your arteries for an abnormal whooshing sound called a bruit (broo-E). Your
doctor can hear a bruit when placing a stethoscope over an affected artery. A
bruit may indicate poor blood flow due to plaque.
Your doctor also may check to see whether any of
your pulses (for example, in the leg or foot) are weak or absent. A weak or
absent pulse can be a sign of a blocked artery.
Diagnostic Tests and Procedures
Your doctor may order one or more tests to diagnose
atherosclerosis. These tests also can help your doctor learn the extent of your
disease and plan the best treatment.
Blood Tests
Blood tests check the levels of certain fats,
cholesterol, sugar, and proteins in your blood. Abnormal levels may show that
you have risk factors for atherosclerosis.
EKG (Electrocardiogram)
An
EKG
is a simple test that detects and records the electrical activity of your
heart. An EKG shows how fast your heart is beating and whether it has a regular
rhythm. It also shows the strength and timing of electrical signals as they
pass through each part of your heart.
Certain electrical patterns that the EKG detects can
suggest whether CAD is likely. An EKG also can show signs of a previous or
current
heart
attack.
Chest X Ray
A chest x ray takes a picture of the organs and
structures inside the chest, including your heart, lungs, and blood vessels.
A chest x ray can reveal signs of
heart
failure.
Ankle/Brachial Index
This test compares the blood pressure in your ankle
with the blood pressure in your arm to see how well your blood is flowing. This
test can help diagnose PAD.
Echocardiography
This test uses sound waves to create a moving
picture of your heart.
Echocardiography
provides information about the size and shape of your heart and how well your
heart chambers and valves are working.
The test also can identify areas of poor blood flow
to the heart, areas of heart muscle that aren't contracting normally, and
previous injury to the heart muscle caused by poor blood flow.
Computed Tomography Scan
A computed tomography, or CT, scan creates
computer-generated images of the heart, brain, or other areas of the body. The
test can often show hardening and narrowing of large arteries.
Stress Testing
During
stress
testing, you exercise to make your heart work hard and beat fast while
heart tests are performed. If you can't exercise, you're given medicine to
speed up your heart rate.
When your heart is beating fast and working hard, it
needs more blood and oxygen. Arteries narrowed by plaque can't supply enough
oxygen-rich blood to meet your heart's needs. A stress test can show possible
signs of CAD, such as:
- Abnormal changes in your heart rate or blood
pressure
- Symptoms such as shortness of breath or chest
pain
- Abnormal changes in your heart rhythm or your
heart's electrical activity
During the stress test, if you can't exercise for as
long as what's considered normal for someone your age, it may be a sign that
not enough blood is flowing to your heart. But other factors besides CAD can
prevent you from exercising long enough (for example, lung diseases,
anemia,
or poor general fitness).
Some stress tests use a radioactive dye, sound
waves, positron emission tomography (PET), or
cardiac
magnetic resonance imaging (MRI) to take pictures of your heart when it's
working hard and when it's at rest.
These imaging stress tests can show how well blood
is flowing in the different parts of your heart. They also can show how well
your heart pumps blood when it beats.
Angiography
Angiography (an-jee-OG-ra-fee) is a test that uses
dye and special x rays to show the insides of your arteries. This test can show
whether plaque is blocking your arteries and how severe the plaque is.
A thin, flexible tube called a catheter is put into
a blood vessel in your arm, groin (upper thigh), or neck. A dye that can be
seen on x ray is then injected into the arteries. By looking at the x-ray
picture, your doctor can see the flow of blood through your arteries.
How Is Atherosclerosis Treated?
Treatments for atherosclerosis may include lifestyle
changes, medicines, and medical procedures or surgery.
Goals of Treatment
The goals of treatment are to:
- Relieve symptoms
- Reduce risk factors in an effort to slow, stop,
or reverse the buildup of plaque
- Lower the risk of blood clots forming
- Widen or bypass clogged arteries
- Prevent diseases related to atherosclerosis
Lifestyle Changes
Making lifestyle changes can often help prevent or
treat atherosclerosis. For some people, these changes may be the only treatment
needed.
- Follow a healthy eating plan to prevent or reduce
high
blood pressure and
high
blood cholesterol and to maintain a healthy weight.
- Increase your physical activity. Check with your
doctor first to find out how much and what kinds of activity are safe for you.
- Lose weight, if you're overweight or obese.
- Quit smoking, if you smoke. Avoid exposure to
secondhand smoke.
- Reduce stress.
Follow a Healthy Eating Plan
For a healthy eating plan, go to the National Heart,
Lung, and Blood Institutes (NHLBIs)
Aim
for a Healthy Weight Web site. This site provides practical tips on healthy
eating, physical activity, and controlling your weight.
Therapeutic Lifestyle Changes
(TLC). Your doctor may recommend TLC if you have high cholesterol. TLC
is a three-part program that includes a healthy diet, physical activity, and
weight management.
With the TLC diet, less than 7 percent of your daily
calories should come from saturated fat. This kind of fat is mainly found in
meat and poultry, including dairy products. No more than 25 to 35 percent of
your daily calories should come from all fats, including saturated,
trans, monounsaturated, and polyunsaturated fats.
You also should have less than 200 mg a day of
cholesterol. The amounts of cholesterol and the different kinds of fat in
prepared foods can be found on the Nutrition Facts label.
Foods high in soluble fiber also are part of a
healthy eating plan. They help block the digestive track from absorbing
cholesterol. These foods include:
- Whole grain cereals such as oatmeal and oat bran
- Fruits such as apples, bananas, oranges, pears,
and prunes
- Legumes such as kidney beans, lentils, chick
peas, black-eyed peas, and lima beans
A diet high in fruits and vegetables can increase
important cholesterol-lowering compounds in your diet. These compounds, called
plant stanols or sterols, work like soluble fiber.
Fish are an important part of a heart healthy diet.
They're a good source of omega-3 fatty acids, which may help protect the heart
from blood clots and inflammation and reduce the risk for
heart
attack. Try to have about two fish meals every week. Fish high in omega-3
fats are salmon, tuna (canned or fresh), and mackerel.
You also should try to limit the amount of sodium
(salt) that you eat. This means choosing low-sodium and low-salt foods and "no
added salt" foods and seasonings at the table or when cooking. The Nutrition
Facts label on food packaging shows the amount of sodium in the item.
Try to limit drinks with alcohol. Too much alcohol
will raise your blood pressure and triglyceride level. (Triglycerides are a
type of fat found in the blood.) Alcohol also adds extra calories, which will
cause weight gain. Men should have no more than two drinks containing alcohol a
day. Women should have no more than one drink containing alcohol a day.
See the NHLBIs
"Your
Guide to Lowering Your Cholesterol With TLC" for more information.
Dietary Approaches to Stop Hypertension
(DASH) eating plan. Your doctor may recommend the DASH eating plan if
you have high blood pressure. The DASH eating plan focuses on fruits,
vegetables, whole grains, and other foods that are heart healthy and lower in
salt/sodium.
This eating plan is low in fat and cholesterol. It
also focuses on fat-free or low-fat milk and dairy products, fish, poultry, and
nuts. The DASH eating plan is reduced in red meats (including lean red meat),
sweets, added sugars, and sugar-containing beverages. It's rich in nutrients,
protein, and fiber.
The DASH eating plan is a good heart healthy eating
plan, even for those who dont have high blood pressure. See the
NHLBIs
"Your
Guide to Lowering Your Blood Pressure With DASH" for more information.
Increase Physical Activity
Regular physical activity can lower many
atherosclerosis risk factors, including LDL ("bad") cholesterol, high blood
pressure, and excess weight. Physical activity also can lower your risk for
diabetes and raise your levels of HDL cholesterol (the "good"
cholesterol that helps prevent atherosclerosis).
Check with your doctor about how much and what kinds
of physical activity are safe for you. Unless your doctor tells you otherwise,
try to get at least 30 minutes of moderate-intensity activity on most or all
days of the week. You can do the activity all at once or break it up into
shorter periods of at least 10 minutes each.
Moderate-intensity activities include brisk walking,
dancing, bowling, bicycling, gardening, and housecleaning.
More intense activities, such as jogging, swimming,
and various sports, also may be appropriate for shorter periods. See the
NHLBIs
"Your
Guide to Physical Activity and Your Heart" for more information.
Maintain a Healthy Weight
Maintaining a healthy weight can decrease your risk
factors for atherosclerosis. A general goal to aim for is a body mass index
(BMI) of less than 25.
BMI measures your weight in relation to your height
and gives an estimate of your total body fat. You can calculate your BMI using
the NHLBI's online calculator,
or your health care provider can calculate your BMI.
A BMI between 25 and 29 is considered overweight. A
BMI of 30 or more is considered obese. A BMI of less than 25 is the goal for
preventing and treating atherosclerosis. Your doctor or other health care
provider can help you determine an appropriate goal for you.
For more information on losing weight and
maintaining your weight, see the Diseases and Conditions Index
Overweight
and Obesity article.
Quit Smoking
If you smoke or use tobacco, quit. Smoking can
damage and tighten blood vessels and raise your risk for atherosclerosis.
The U.S. Department of Health and Human Services has
information on how to
quit smoking.
Reduce Stress
Research shows that the most commonly reported
"trigger" for a heart attack is an emotionally upsetting
eventparticularly one involving anger. Also, some of the ways people cope
with stress, such as drinking, smoking, or overeating, aren't heart healthy.
Physical activity can help relieve stress and reduce
other atherosclerosis risk factors. Many people also find that meditation or
relaxation therapy helps them reduce stress.
Medicines
To help slow or reverse atherosclerosis, your doctor
may prescribe medicines to help lower your cholesterol or blood pressure or
prevent blood clots from forming.
For successful treatment, take all medicines as your
doctor prescribes.
Medical Procedures and Surgery
If you have severe atherosclerosis, your doctor may
recommend one of several procedures or surgeries.
Angioplasty
is a procedure to open blocked or narrowed coronary (heart) arteries.
Angioplasty can improve blood flow to the heart, relieve chest pain, and
possibly prevent a heart attack. Sometimes a small mesh tube called a
stent
is placed in the artery to keep it open after the procedure.
Coronary
artery bypass grafting (CABG) is a type of surgery. In CABG, arteries or
veins from other areas in your body are used to bypass (that is, go around)
your narrowed coronary arteries. CABG can improve blood flow to your heart,
relieve chest pain, and possibly prevent a heart attack.
Bypass grafting also can be used for leg arteries.
In this surgery, a healthy blood vessel is used to bypass a narrowed or blocked
blood vessel in one of your legs. The healthy blood vessel redirects blood
around the artery, improving blood flow to the leg.
Carotid artery surgery removes plaque buildup from
the carotid arteries in the neck. This opens the arteries and improves blood
flow to the brain. Carotid artery surgery can help prevent a
stroke.
How Can Atherosclerosis Be Prevented or
Delayed?
Taking action to control your
risk factors can help prevent or delay
atherosclerosis and its related diseases. Your chance of developing
atherosclerosis goes up with the number of risk factors you have.
Making lifestyle changes and taking prescribed
medicines are important steps. See "How Is
Atherosclerosis Treated?" for information on healthy eating plans, physical
activity, maintaining a healthy weight, and medicines.
Know your family history of health problems related
to atherosclerosis. If you or someone in your family has this disease, be sure
to tell your doctor. Also, let your doctor know if you smoke.
Living With Atherosclerosis
Improved treatments have reduced deaths from
atherosclerosis-related diseases. These treatments also have improved the
quality of life for people with these diseases.
You may be able to prevent or delay atherosclerosis
and the problems it can cause, mainly by maintaining a healthy lifestyle. This,
along with ongoing medical care, can help you avoid the problems of
atherosclerosis and live a long, healthy life.
Research continues look for ways to improve the
health of people who have atherosclerosis or may get it. The goals of research
are to:
- Find more effective medicines
- Identify people at greatest risk earlier
- Find out how well alternative treatments
work
Ongoing Health Care Needs
If you have atherosclerosis, work closely with your
doctor and other health care providers to avoid serious problems, like
heart
attack and
stroke.
Talk to your doctor about how often you should
schedule office visits or blood tests. Be sure to let your doctor know if you
develop new symptoms or if your symptoms worsen.
Support Groups
Community resources are available to help you learn
more about atherosclerosis. Contact your local public health departments,
hospitals, and local chapters of national health organizations to learn more
about available resources in your area.
Talk about your lifestyle changes with your spouse,
family, or friendswhoever can provide support or needs to understand why
you're changing your habits. They may be able to help you make lifestyle
changes, like helping you plan healthier meals.
Because atherosclerosis tends to run in families,
your lifestyle changes may help many of your family members too.
Key Points
- Atherosclerosis is a disease in which plaque
builds up on the insides of your arteries.
- Over time, plaque hardens and narrows your
arteries. The flow of oxygen-rich blood to your organs and other parts of your
body is reduced. This can lead to serious problems, including
heart
attack,
stroke, or even death.
- Atherosclerosis can affect any artery in the
body.
- Coronary
artery disease (CAD) occurs when plaque builds up in the coronary (heart)
arteries. CAD is a leading cause of death in the United States.
- Carotid artery disease happens when plaque builds up in the
carotid arteries (the arteries that supply blood and oxygen to your
brain).
-
Peripheral
arterial disease (PAD) occurs when plaque builds up in the major arteries
of the legs, arms, and pelvis.
- The exact cause of atherosclerosis isnt
known. It may start when certain factors damage the inner layers of arteries.
When damage occurs, your body starts a healing process. This healing causes
plaque to build up where the arteries are damaged. Over time, the plaque may
crack and causes blood clots to form in the arteries. This can worsen
angina
(chest pain) or cause a heart attack.
- Many factors raise your risk for atherosclerosis.
Major risk factors include
unhealthy
cholesterol levels,
high
blood pressure, smoking, insulin resistance,
diabetes,
overweight
or obesity, lack of physical activity, age, and a family history of early
heart disease.
- Atherosclerosis usually doesn't cause signs and
symptoms until it severely narrows or totally blocks an artery. Many people
don't know they have the disease until they have a medical emergency, such as a
heart attack or stroke. Other signs and symptoms depend on which arteries are
narrowed or blocked.
- Your doctor will diagnose atherosclerosis based
on your medical and family histories, your risk factors, and the results of a
physical exam and diagnostic tests.
- Treatments for atherosclerosis may include
lifestyle changes, medicines, and medical procedures and surgery. Lifestyle
changes include following a healthy eating plan, increasing physical activity,
maintaining a healthy weight, quitting smoking, and reducing stress.
- Taking steps to control your risk factors can
help prevent or delay atherosclerosis and its related diseases. These steps
include making lifestyle changes and/or taking medicines as prescribed by your
doctor.
- Improved treatments have helped reduce deaths
from atherosclerosis-related diseases. However, the number of people diagnosed
with atherosclerosis remains high.
- If you've been diagnosed with atherosclerosis,
you can control the disease with lifestyle changes and/or medicines. See your
doctor regularly, and call him or her if you develop any new symptoms or your
symptoms worsen.
Links to Other Information About
Atherosclerosis
NHLBI Resources
Non-NHLBI Resources
Clinical Trials
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