What Is Coronary Artery Bypass Grafting?
Coronary artery bypass grafting (CABG) is a type of
surgery called revascularization (re-VAS-kyu-lar-i-ZA-shun), used to improve
blood flow to the heart in people with severe
coronary
artery disease (CAD).
CAD occurs when the arteries that supply blood to
the heart muscle (the coronary arteries) become blocked due to the buildup of a
material called plaque (plak) on the inside of the blood vessels. If the
blockage is severe, chest pain (also called
angina),
shortness of breath, and, in some cases,
heart
attack can occur.
CABG is one treatment for CAD. During CABG, a
healthy artery or vein from another part of the body is connected, or grafted,
to the blocked coronary artery. The grafted artery or vein bypasses (that is,
it goes around) the blocked portion of the coronary artery. This new passage
routes oxygen-rich blood around the blockage to the heart muscle. As many as
four major blocked coronary arteries can be bypassed during one surgery.
Overview
CABG is the most common type of open-heart surgery
in the United States, with more than 500,000 surgeries performed each year.
Doctors called cardiothoracic (KAR-de-o-tho-RAS-ik) surgeons perform this
surgery.
CABG isnt used for everyone with CAD. Many
people with CAD can be treated by other means, such as lifestyle changes,
medicines, and another revascularization procedure called
angioplasty.
CABG may be an option if you have severe blockages
in the large coronary arteries that supply a major part of the heart muscle
with bloodespecially if the hearts pumping action has already been
weakened.
CABG may also be an option if you have blockages in
the heart that cant be treated with angioplasty. In these situations,
CABG is considered more effective than other types of treatment.
If youre a candidate for CABG, the goals of
having the surgery are to:
- Improve your quality of life and decrease angina
and other symptoms of CAD
- Resume a more active lifestyle
- Improve the pumping action of the heart if it has
been damaged by a heart attack
- Lower the chances of a heart attack (in some
patients, such as those with diabetes)
- Improve your chance of survival
Repeat surgery may be needed if grafted arteries or
veins become blocked, or if new blockages develop in arteries that werent
blocked before. Taking medicines as prescribed and making lifestyle changes
that your doctor recommends can lower the chance of a graft becoming
blocked.
In people who are candidates for the surgery, the
results are usually excellent, with 85 percent of people having significantly
reduced symptoms, less risk for future heart attacks, and a decreased chance of
dying within 10 years following the surgery.
Types of Coronary Artery Bypass Grafting
Traditional Coronary Artery Bypass Grafting
This is the most common type of coronary artery
bypass grafting (CABG). Its used when at least one major artery needs to
be bypassed. During the surgery, the chest bone is opened to access the heart.
Medicines are given to stop the heart, and a heart-lung machine is used to keep
blood and oxygen moving throughout the body during surgery. This allows the
surgeon to operate on a still heart. After surgery, the heart is restarted
using mild electric shocks.
Off-Pump Coronary Artery Bypass Grafting
This type of CABG is similar to traditional CABG in
that the chest bone is opened to access the heart. However, the heart
isnt stopped, and a heart-lung machine isnt used. Off-pump CABG is
sometimes called beating heart bypass grafting. This type of surgery may reduce
complications that can occur when a heart-lung machine is used, and it may
speed up recovery time after surgery.
Minimally Invasive Direct Coronary Artery Bypass
Grafting
This surgery is similar to off-pump, but instead of
a large incision to open the chest bone, several small incisions are made on
the left side of the chest between the ribs. This type of surgery is used
mainly for bypassing the vessels in front of the heart. Its a fairly new
procedure, which is performed less often than the other types. This type of
surgery is not for everybody, especially if more than one or two coronary
arteries need to be bypassed.
Other Names for Coronary Artery Bypass
Grafting
- Bypass surgery
- Coronary artery bypass surgery
- Heart bypass surgery
Who Needs Coronary Artery Bypass Grafting?
Coronary artery bypass grafting (CABG) is only used
to treat people who have severe
coronary
artery disease (CAD) that could lead to a
heart
attack.
Your doctor may recommend CABG if other treatments,
such as lifestyle changes or medicines, havent worked. He or she also may
recommend CABG if you have severe blockages in the large coronary arteries that
supply a major part of the heart muscle with bloodespecially if your
hearts pumping action has already been weakened.
CABG also may be a treatment option if you have
blockages in the heart that cant be treated with
angioplasty.
Your doctor will determine if youre a
candidate for CABG based on a number of factors. These include the presence and
severity of CAD symptoms, the severity and location of blockages in your
coronary arteries, your response to other treatments, your quality of life, and
any other medical problems you may have.
In some cases, CABG may be performed on an emergency
basis, such as pending or during a heart attack.
Physical Exam and Diagnostic Tests
To determine if youre a candidate for CABG,
your doctor will do a physical exam that involves checking your cardiovascular
system, focusing on heart, lungs, and pulse. Your doctor also will ask you
about any symptoms you have, such as chest pain or shortness of breath, and how
long, how often, and how severe they are.
Medical tests will be done to find out which
arteries are clogged, how much theyre clogged, and whether theres
any heart damage. Tests may include:
- EKG
(electrocardiogram). An EKG is a simple test that detects and records the
electrical activity of the heart. This test is used to help detect and locate
the source of heart problems. An EKG shows how fast the heart is beating,
whether the hearts rhythm is steady or irregular, where in the heart the
electrical activity starts, and whether the electrical activity is traveling
through the heart in a normal way.
- Stress test. Some heart problems are easier to
diagnose when your heart is working harder and beating faster than when
its at rest. During stress testing, you exercise (or are given medicine
if youre unable to exercise) to make your heart work harder and beat
faster while heart tests are performed.
During exercise stress testing,
your blood pressure and EKG readings are monitored while you walk or run on a
treadmill or pedal a bicycle. Other heart tests, such as nuclear heart scanning
or echocardiography, also can be done at the same time. These would be ordered
if your doctor needs more detailed information on blood flow and the
hearts pumping action than the exercise stress test can provide.
If you are unable to exercise, a medicine can be injected through an
intravenous line (IV) into your bloodstream to make your heart work harder and
beat faster, as if you are exercising on a treadmill or bicycle. Nuclear heart
scanning or echocardiography is then usually done.
During nuclear heart
scanning, radioactive tracer is injected into your bloodstream, and a special
camera shows the flow of blood through your heart and arteries.
Echocardiography uses sound waves to show blood flow through the chambers and
valves of your heart and to show how well your heart pumps.
Your doctor
also may order two newer tests along with stress testing if more information is
needed about how well your heart works. These new tests are magnetic resonance
imaging (MRI) and positron emission tomography (PET) scanning of the heart. MRI
shows detailed images of the structures and beating of your heart, which may
help your doctor better assess if parts of your heart are weak or damaged. PET
scanning shows the level of metabolic activity in different areas of your
heart. This can help your doctor determine if enough blood is flowing to the
areas of your heart. A PET scan can show decreased blood flow caused by disease
or damaged muscles that may not be detected by other scanning methods.
- Echocardiogram. This test uses sound waves to create a moving
picture of your heart. Echocardiogram provides information about the size and
shape of your heart and how well your heart chambers and valves are
functioning. The test also can identify areas of poor blood flow to the heart,
areas of heart muscle that are not contracting normally, and previous injury to
the heart muscle caused by poor blood flow.
There are several different
types of echocardiograms, including a stress echocardiogram. During this test,
an echocardiogram is done both before and after your heart is stressed either
by having you exercise or by injecting a medicine into your bloodstream that
makes your heart beat faster and work harder. A stress echocardiogram is
usually done to find out if you have decreased pumping action of your heart
(CAD).
- Angiography. Angiography uses a special dye injected into the
bloodstream to outline the insides of arteries on x-ray pictures. An angiogram
shows the location and severity of blockages in blood vessels.
Other Considerations
When deciding if youre a candidate for CABG,
you doctor will also consider your:
- History and past treatment of heart disease,
including surgeries, procedures, or medicines
- History of other diseases and conditions
- Age and general health
- Family history of CAD, heart attack, or other
heart diseases
Medicines and other medical procedures may be tried
before CABG. Medicines that lower cholesterol levels and blood pressure and
improve blood flow through the coronary arteries are often tried.
A procedure called
coronary
angioplasty (also called balloon angioplasty) may be tried. During this
procedure, a thin tube with a balloon or other device on the end is threaded
through a blood vessel in your groin (upper thigh) or arm up to the narrowed or
blocked coronary artery. Once in place, the balloon is inflated to push the
plaque against the wall of the artery, widening the artery and restoring the
flow of blood through it. In many cases, after the initial balloon angioplasty,
a tiny mesh tube called a
stent
is inserted permanently in the area to keep the artery open.
What To Expect Before Coronary Artery Bypass
Grafting
Tests may be done to prepare you for coronary artery
bypass grafting, including blood tests,
EKG,
echocardiogram,
chest x ray,
cardiac
catheterization, and
angiography.
Your doctor will give you specific instructions
about how to prepare for surgery. There will be instructions about what to eat
or drink, what medicines to take, and what activities to stop (such as
smoking). You will likely be admitted to the hospital on the same day as the
surgery.
What To Expect During Coronary Artery Bypass
Grafting
Coronary artery bypass grafting (CABG) requires a
team of experts. A cardiothoracic surgeon performs the surgery with support
from an anesthesiologist, perfusionist (heart-lung machine specialist), other
surgeons, and nurses.
There are several different types of CABG. They
range from traditional surgery in which the chest is opened to reach the heart,
to a nontraditional surgery in which small incisions are made to bypass the
narrowed artery.
Traditional Coronary Artery Bypass Grafting
This type of surgery usually lasts 3 to 5 hours,
depending on the number of arteries being bypassed. Numerous steps take place
during traditional CABG.
Anesthesia is given to put you to sleep. During the
surgery, the anesthesiologist monitors your heartbeat, blood pressure, oxygen
levels, and breathing. A breathing tube is placed in your lungs through your
throat, and connected to a ventilator (breathing machine).
An incision is made down the center of your chest.
The chest bone is then cut and your ribcage is opened so that the surgeon can
get to your heart.
Medicines are used to stop your heart, which allows
the surgeon to operate on it while its not beating. A heart-lung machine
keeps oxygen-rich blood moving throughout your body. An artery or vein is taken
from a different part of your body, such as your chest or leg, and prepared to
be used as a graft for the bypass. In surgery with several bypasses, a
combination of both artery and vein grafts is commonly used.
- Artery grafts. These grafts are much less likely
than vein grafts to become blocked over time. The left internal mammary artery
is most commonly used for an artery graft. Its located inside the chest
close to the heart. Arteries from the arm or other places in the body are
sometimes used as well.
- Vein grafts. Although veins are commonly used as
grafts, theyre more likely than artery grafts to develop plaque and
become blocked over time. The saphenous veina long vein running along the
inner side of the legis typically used.
After the grafting is complete, your heart is
restarted using mild electric shocks. Youre disconnected from the
heart-lung machine. Tubes are inserted into your chest to drain fluid.
The surgeon uses wires that stay in your body
permanently to close your chest bone and stitches or staples to close the skin
incision. The breathing tube is removed when youre able to breathe
without it.
Nontraditional Coronary Artery Bypass Grafting
Nontraditional CABG includes off-pump CABG and
minimally invasive CABG.
Off-Pump Coronary Artery Bypass Grafting
This type of surgery can be used to bypass any of
the coronary arteries. Off-pump CABG also is called beating heart bypass
grafting because the heart isnt stopped and a heart-lung machine
isnt used. Instead, the part of the heart where grafting is being done is
steadied with a mechanical device.
Off-pump CABG may reduce complications that can
occur when a heart-lung machine is used, especially in people who have had a
stroke or mini-strokes in the past, who are over age 70, and who
have diabetes, lung disease, or kidney disease.
Other advantages of this type of bypass surgery
include:
- Reduced bleeding during surgery and a lower
chance of needing a blood transfusion
- A lower chance of infection, stroke, and kidney
complications
- A lower chance of complications such as memory
loss, difficulty concentrating, or difficulty thinking clearly
- Faster recovery from the surgery
Minimally Invasive Direct Coronary Artery Bypass
Grafting
There are several types of minimally invasive direct
coronary artery bypass (MIDCAB) grafting. These types of surgery differ from
traditional bypass surgery because they only require small incisions rather
than opening the chest bone to get to the heart. These procedures sometimes use
a heart-lung machine.
MIDCAB procedure. This procedure is
used when only one or two coronary arteries need to be bypassed. A series of
small incisions is made between your ribs on the left side of your chest,
directly over the artery to be bypassed. The incisions are usually about 3
inches long. (The incisions made in traditional CABG are at least 6 to 8 inches
long.) The left internal mammary artery is most often used for the graft. A
heart-lung machine isnt used during this procedure.
Port-access coronary artery bypass
procedure. This procedure is performed through small incisions (ports)
made in your chest. Artery or vein grafts are used. The heart-lung machine is
used during this procedure.
Robot-assisted technique. This type
of procedure allows for even smaller, keyhole-sized incisions. A small video
camera is inserted in one incision to show the heart, while the surgeon uses
remotely controlled surgical instruments to perform the surgery. The heart-lung
machine is sometimes used during this procedure.
Advantages of minimally invasive CABG include
smaller incisions, smaller scars, shorter recovery and hospital stay, less
bleeding, less chance for infection, and less pain.
What To Expect After Coronary Artery Bypass
Grafting
Recovery in the Hospital
After surgery, you will typically spend 1 or 2 days
in an intensive care unit. Your heart rate and blood pressure will be
continuously monitored during this time. Intravenous medicines (medicines
injected through a vein) are often given to regulate blood circulation and
blood pressure. You will then be moved to a less intensive care area of the
hospital for 3 to 5 days before going home.
Recovery at Home
Your doctor will give you specific instructions for
recovering at home, especially concerning:
- How to care for your healing incisions
- How to recognize signs of infection or other
complications
- When to call the doctor immediately
- When to make followup appointments
You may also receive instructions on how to deal
with common after-effects from surgery. After-effects often go away within 4 to
6 weeks after surgery, but may include:
- Discomfort or itching from healing incisions
- Swelling of the area where an artery or vein was
taken for grafting
- Muscle pain or tightness in the shoulders and
upper back
- Fatigue (tiredness), mood swings, or
depression
- Difficulty sleeping or loss of appetite
- Constipation
- Chest pain around the site of the chest bone
incision (more frequent with the traditional surgery)
Full recovery from traditional CABG may take 6 to 12
weeks or more. Less recovery time is needed for nontraditional CABG.
Your doctor will provide instructions on resuming
physical activity. This varies from person to person, but there are some
typical timeframes. Most people can resume sexual activity within about 4 weeks
and driving after 3 to 8 weeks.
Returning to work after 6 weeks is common unless the
job involves specific and demanding physical activity. Some people may need to
find less physically demanding types of work or work a reduced schedule at
first.
Ongoing Care
Care after surgery may include periodic checkups
with doctors. During these visits, tests may be done to see how the heart is
working. Tests may include
EKG,
stress testing, and
echocardiogram.
CABG is not a cure for
coronary
artery disease (CAD). You and your doctor may develop a management plan
that includes lifestyle changes to help you stay healthy and reduce the chances
of CAD getting worse. Lifestyle changes may include quitting smoking, making
changes in your diet, getting regular exercise, and lowering and managing
stress.
In some cases, your doctor may refer you to a
cardiac rehabilitation (rehab) program. These programs can help you recover
through supervised physical activity and education on how to make choices that
reduce your risk for future heart problems and help you get back to your
regular lifestyle after surgery.
Doctors supervise these programs, which include
counseling about lifestyle changes as well as exercise training to build
strength and energy. Cardiac rehab programs may be offered in hospitals and
other community facilities. Ask your doctor whether youre a candidate for
cardiac rehab.
Taking medicines as prescribed also is an important
part of care after surgery. Medicines may be prescribed to manage pain during
recovery; lower cholesterol, blood pressure, and the chance of developing blood
clots; manage diabetes; or treat depression.
What Are the Risks of Coronary Artery Bypass
Grafting?
Although complications from coronary artery bypass
grafting (CABG) are uncommon, the risks include:
- Wound infection and bleeding
- Anesthesia reactions
- Fever
- Pain
- Stroke,
heart
attack, or even death
Some patients can develop a fever associated with
chest pain, irritability, and decreased appetite. This is due to inflammation
involving the lung and heart sac, and is sometimes seen 1 to 6 weeks after
surgeries that involve cutting through the pericardium (the outer covering of
the heart). This reaction is usually a mild, self-limited illness, but some
patients may develop fluid buildup around the heart that requires
treatment.
Use of the heart-lung machine also can cause
complications. Memory loss and other changes, such as difficulty concentrating
or thinking clearly, may occur in some people. These changes are more likely to
occur in people who are older, who have
high
blood pressure or lung disease, or who drink excessive amounts of alcohol.
These side effects often improve several months after surgery.
The heart-lung machine also increases the risk of
blood clots forming in your blood vessels. Clots can travel to the brain or
other parts of the body and block the flow of blood, which can cause stroke or
other problems. Recent technical improvements in heart-lung machines are
helping to reduce the risk of blood clots forming.
In general, the chances of developing complications
are higher when CABG is done in an emergency situation (for example, if
performed during a heart attack), if youre over age 70, or if you have a
history of smoking. Your risks also are higher if you have other diseases or
conditions such as diabetes, kidney disease, lung disease, or
peripheral
vascular disease.
Key Points
- Coronary artery bypass grafting (CABG) is a type
of surgery used to improve blood flow to the heart in people with severe
coronary
artery disease (CAD).
- During CABG, a healthy artery or vein from
another part of the body is connected, or grafted, to a blocked coronary
artery. The grafted artery or vein bypasses (that is, it goes around) the
blocked portion of the coronary artery. This improves the flow of blood and
oxygen to your heart muscle.
- CABG is one type of treatment for CAD. Not
everyone with CAD needs CABG. In people who are candidates for the surgery, the
results are usually excellent, with 85 percent of people having significantly
reduced symptoms, less risk for future
heart
attacks, and a decreased chance of dying within 10 years following the
surgery.
- Your doctor will determine if youre a
candidate for CABG based on a number of factors, including the presence and
severity of CAD. Often nonsurgical treatments, such as medicines and
angioplasty,
will be tried first.
- Although the surgery is usually done on an
elective (scheduled) basis, it may need to be performed in an emergency, such
as pending or during a heart attack.
- Although complications are rare, risks of CABG
include infection at the incision site, bleeding, reactions to the anesthesia,
fever and pain, stroke, heart attack, or even death.
- Recovery may take 6 to 12 weeks or more. Most
people can get back to their normal activities about 6 weeks after the
surgery.
- Care after surgery may include followup visits
with doctors, lifestyle changes to prevent further progression of CAD, and
taking medicines as prescribed.
Links to Other Information About Coronary Artery
Bypass Grafting
NHLBI Resources
Non-NHLBI Resources
Clinical Trials
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