What Is Patent Ductus Arteriosus?
Patent ductus arteriosus (PDA) is a heart problem
that occurs soon after birth in some babies. In PDA, abnormal blood flow occurs
between two of the major arteries connected to the heart.
Before birth, the two major arteries—the aorta
and the pulmonary (PULL-mun-ary) artery—are connected by a blood vessel
called the ductus arteriosus. This vessel is an essential part of fetal blood
circulation.
Within minutes or up to a few days after birth, the
vessel is supposed to close as part of the normal changes occurring in the
baby's circulation.
In some babies, however, the ductus arteriosus
remains open (patent). This opening allows oxygen-rich blood from the aorta to
mix with oxygen-poor blood from the pulmonary artery. This can put strain on
the heart and increase blood pressure in the lung arteries.
Normal Heart and Heart With Patent
Ductus Arteriosus
Figure A shows the interior of a
normal heart and normal blood flow. Figure B shows a heart with patent ductus
arteriosus. The defect connects the aorta with the pulmonary artery. This
allows oxygen-rich blood from the aorta to mix with oxygen-poor blood in the
pulmonary artery.
Overview
A PDA is a type of
congenital
heart defect. A congenital heart defect is any type of heart problem
that’s present at birth.
If your baby has a PDA but an otherwise normal
heart, the PDA may shrink and go away. Some children need treatment to close
their PDAs.
If your baby is born with another heart defect (in
addition to PDA) that decreases blood flow from the heart to the lungs or that
decreases the flow of oxygen-rich blood to the body, medicine may be given to
keep the ductus arteriosus open.
This helps maintain blood flow and oxygen levels
until doctors can do corrective surgery for the heart defect.
Outlook
PDA is a relatively common congenital heart defect
in the United States. The condition occurs more often in premature infants (on
average, occurring in about 8 of every 1,000 births). However, PDA also occurs
in full-term infants (on average, occurring in about 2 of every 1,000 births).
Premature babies who have PDA are more vulnerable
to its effects. PDA is twice as common in girls as it is in boys.
The next section provides more information about a
normal heart compared to a heart with PDA. See that section for a more detailed
description of the anatomy and circulation of a normal heart.
How the Heart Works
To understand patent ductus arteriosus, it helps to
know how a normal heart works. Your child's heart is a muscle about the size of
his or her fist. It works like a pump and beats about 100,000 times a day.
The heart has two sides, separated by an inner wall
called the septum. The right side of the heart pumps blood to the lungs to pick
up oxygen. Then, oxygen-rich blood returns from the lungs to the left side of
the heart, and the left side pumps it to the body.
The heart has four chambers and four valves and is
connected to various blood vessels. Veins are the blood vessels that carry
blood from the body to the heart. Arteries are the blood vessels that carry
blood away from the heart to the body.
A Healthy Heart Cross-Section
The illustration shows a
cross-section of a healthy heart and its inside structures. The blue arrow
shows the direction in which oxygen-poor blood flows from the body to the
lungs. The red arrow shows the direction in which oxygen-rich blood flows from
the lungs to the rest of the body.
Heart Chambers
The heart has four chambers or "rooms."
- The atria (AY-tree-uh) are the two upper chambers
that collect blood as it comes into the heart.
- The ventricles (VEN-trih-kuls) are the two lower
chambers that pump blood out of the heart to the lungs or other parts of the
body.
Heart Valves
Four valves control the flow of blood from the
atria to the ventricles and from the ventricles into the two large arteries
connected to the heart.
- The tricuspid (tri-CUSS-pid) valve is in the
right side of the heart, between the right atrium and the right ventricle.
- The pulmonary valve is in the right side of the
heart, between the right ventricle and the entrance to the pulmonary artery,
which carries blood to the lungs.
- The mitral (MI-trul) valve is in the left side
of the heart, between the left atrium and the left ventricle.
- The aortic (ay-OR-tik) valve is in the left side
of the heart, between the left ventricle and the entrance to the aorta, the
artery that carries blood to the body.
Valves are like doors that open and close. They
open to allow blood to flow through to the next chamber or to one of the
arteries, and then they shut to keep blood from flowing backward.
When the heart's valves open and close, they make a
"lub-DUB" sound that a doctor can hear using a stethoscope.
- The first sound—the "lub"—is made by
the mitral and tricuspid valves closing at the beginning of systole
(SIS-toe-lee). Systole is when the ventricles contract, or squeeze, and pump
blood out of the heart.
- The second sound—the "DUB"—is made by
the aortic and pulmonary valves closing at the beginning of diastole
(di-AS-toe-lee). Diastole is when the ventricles relax and fill with blood
pumped into them by the atria.
Arteries
The arteries are major blood vessels connected to
your heart.
- The pulmonary artery carries blood pumped from
the right side of the heart to the lungs to pick up a fresh supply of oxygen.
- The aorta is the main artery that carries
oxygen-rich blood pumped from the left side of the heart out to the body.
- The coronary arteries are the other important
arteries attached to the heart. They carry oxygen-rich blood from the aorta to
the heart muscle, which must have its own blood supply to function.
Veins
The veins also are major blood vessels connected to
your heart.
- The pulmonary veins carry oxygen-rich blood from
the lungs to the left side of the heart so it can be pumped out to the body.
- The superior and inferior vena cavae are large
veins that carry oxygen-poor blood from the body back to the heart.
For more information on how a healthy heart works,
see the Diseases and Conditions Index
How
the Heart Works article. This article has animations that show how your
heart pumps blood and how your heart's electrical system works.
The Heart With Patent Ductus Arteriosus
The ductus arteriosus is a blood vessel that
connects a baby's aorta and pulmonary artery while the baby is in the womb.
This connection allows blood to be pumped from the right side of the heart
straight to the aorta, without stopping at the lungs for oxygen.
While a baby is in the womb, only a small amount of
his or her blood needs to go to the lungs. This is because the baby gets oxygen
from the mother's bloodstream.
After birth, the baby is no longer connected to the
mother's bloodstream. The baby's blood must now go to his or her own lungs to
get oxygen. Normally, as the baby begins to breathe on his or her own, the
pulmonary artery opens to allow blood into the lungs, and the ductus arteriosus
closes.
Once the ductus arteriosus closes, blood leaving
the right side of the heart no longer goes straight to the aorta. First, it
goes through the left and right pulmonary arteries and through the lungs to
pick up oxygen. Then, the oxygen-rich blood returns to the left side of the
heart and is pumped out to the rest of the body.
If the ductus arteriosus doesn't close after birth
as it should, it's called a patent ductus arteriosus (PDA). A PDA allows blood
to flow directly from the aorta into the pulmonary artery and to the lungs.
This extra amount of blood flowing into the lungs strains the heart and
increases blood pressure in the lung's arteries.
Effects of Patent Ductus Arteriosus
Full-term infants. A small PDA
might not cause any problems, but a large PDA likely will cause problems. The
larger a PDA is, the greater the amount of extra blood that passes through the
lungs.
A large PDA that remains open for an extended time
can cause the heart to enlarge, forcing it to work harder. Also, fluid can
build up in the lungs.
A PDA can slightly increase the risk of
infective
endocarditis (IE). IE is an infection of the lining of the heart, valves,
or arteries.
In the case of PDA, the increased flow of blood can
irritate the lining of the pulmonary artery where the ductus arteriosus
connects. This irritation makes it easier for bacteria in the bloodstream to
collect and grow there, which can lead to IE.
Premature infants. PDA can be more serious
in premature babies than in full-term babies.
Premature infants who have PDA are more likely to
have damage to their lungs from the extra blood flowing through the PDA. These
infants may need to be on
ventilators
to help them breathe.
The increased flow of blood through the lungs also
can reduce blood flow to the rest of the body. This can damage other organs,
especially the intestines and kidneys.
What Causes Patent Ductus Arteriosus?
The cause of patent ductus arteriosus isn't known.
Genetics may play a role. A defect in one or more genes could prevent the
ductus arteriosus from closing normally after birth.
Who Is At Risk for Patent Ductus Arteriosus?
Patent ductus arteriosus (PDA) is a relatively
common congenital
heart defect in the United States.
The condition occurs more often in premature
infants (on average, occurring in about 8 of every 1,000 births). However, PDA
also occurs in full-term infants (on average, occurring in about 2 of every
1,000 births).
PDA also is more common in:
- Infants who have genetic conditions such as Down
syndrome
- Infants whose mothers had German measles
(rubella) during pregnancy
PDA is twice as common in girls as it is in
boys.
What Are the Signs and Symptoms of Patent Ductus
Arteriosus?
A
heart
murmur may be the only sign that a baby has patent ductus arteriosus (PDA).
A heart murmur is an extra or unusual sound heard during the heartbeat. Heart
murmurs also have other causes besides PDA, and most murmurs are harmless.
Some infants may develop signs or symptoms of
volume overload on the heart and excess blood flow in the lungs. Signs and
symptoms may include:
- Fast breathing, working hard to breathe, or
shortness of breath. Premature infants may need increased oxygen or help
breathing from a
ventilator.
- Poor feeding and poor weight gain.
- Tiring easily.
- Sweating with exertion, such as while
feeding.
How Is Patent Ductus Arteriosus Diagnosed?
In full-term infants, patent ductus arteriosus
(PDA) usually is first suspected when the baby's doctor hears a
heart
murmur during a regular checkup.
A heart murmur is an extra or unusual sound heard
during the heartbeat. Heart murmurs also have other causes besides PDA, and
most murmurs are harmless.
If a PDA is large, the infant also may develop
symptoms of volume overload and increased blood flow to the lungs. If a PDA is
small, it may not be diagnosed until later in childhood.
If your child's doctor thinks your child has PDA,
he or she may refer you to a pediatric cardiologist. This is a doctor who
specializes in diagnosing and treating heart problems in children.
Premature babies who have PDA may not have the same
signs as full-term babies, such as heart murmurs. Doctors may suspect PDA in
premature babies who develop breathing problems soon after birth. Tests can
help confirm a diagnosis.
Diagnostic Tests
Echocardiography
Echocardiography (echo) is a painless test that uses sound waves to create
a moving picture of your baby's heart. During echo, the sound waves bounce off
your child’s heart. A computer converts the sound waves into pictures of
the heart’s structures.
The test allows the doctor to clearly see any
problems with the way the heart is formed or the way it's working. Echo is the
most important test available to your baby's cardiologist to both diagnose a
heart problem and follow the problem over time.
In babies who have PDA, echo shows how big the PDA
is and how well the heart is responding to it. When medical treatments are used
to try to close a PDA, echo is used to see how well the treatments are working.
EKG (Electrocardiogram)
An
EKG
is a simple, painless test that records the heart's electrical activity. For
babies who have PDA, an EKG can show whether the heart is enlarged. The test
also can show other subtle changes that can suggest the presence of a
PDA.
How Is Patent Ductus Arteriosus Treated?
Patent ductus arteriosus (PDA) is treated with
medicines, catheter-based procedures, and surgery. The goal of treatment is to
close the PDA to prevent complications and reverse the effects of increased
blood volume.
Small PDAs often close without treatment. For
full-term infants, treatment is needed if the child's PDA is large or causing
health problems.
For premature infants, treatment is needed if the
PDA is causing breathing problems or heart problems.
Talk to your child's doctor about treatment options
and your family's preferences on treatment decisions.
Medicines
Your child's doctor may prescribe medicines to help
close your child's PDA.
Indomethacin is a medicine that helps close PDAs in
premature infants. This medicine works by stimulating the PDA to constrict or
tighten, closing the opening. Indomethacin usually doesn't work in full-term
infants.
Ibuprofen is a medicine in the same family as
indomethacin. It's also frequently used to close PDAs in premature infants.
Catheter-Based Procedures
Catheters are thin, flexible tubes used in a
procedure called
cardiac
catheterization (KATH-e-ter-i-ZA-shun). Catheter-based procedures often are
used to close PDAs in infants or children who are large enough to have the
procedure.
Your child's doctor may refer to the procedure as
"transcatheter device closure." The procedure sometimes is done on small PDAs
to prevent the risk of
infective
endocarditis (IE), an infection of the lining of the heart, valves, or
arteries.
During the procedure, your child will be sedated or
given medicine so that he or she will sleep and not feel any discomfort. The
doctor will place a catheter in a large blood vessel in the upper thigh (groin)
and guide it to your child's heart.
A small metal coil or other blocking device is then
passed up through the catheter and placed in the PDA to block blood flow
through the vessel.
Catheter-based procedures don't require the child's
chest to be opened. They also let the child recover quickly.
Closing a PDA using a catheter often is done on an
outpatient basis. You'll most likely be able to take your child home the same
day the procedure is done.
Complications from catheter-based procedures are
rare and short term. They can include bleeding, infection, and movement of the
blocking device from where it was placed.
Surgery
Surgery for PDA may be done if:
- A premature or full-term infant develops health
problems from the PDA and is too small to have a catheter-based procedure
- A PDA isn't successfully closed by a
catheter-based procedure
- Surgery is planned for treatment of related
congenital
heart defects
Often, surgery isn't done until after 6 months of
age in infants who don't have health problems from their PDAs. Doctors sometime
perform surgery on small PDAs to prevent the risk of IE.
For the surgery, your child will be given medicine
so that he or she will sleep and not feel any discomfort. The surgeon will make
a small cut between your child's ribs to reach the PDA. He or she will then
close the PDA with stitches or clips.
Complications from surgery are rare and usually
short term. They can include hoarseness, a paralyzed diaphragm (the muscle
below the lungs), infection, bleeding, or fluid buildup around the lungs.
After Surgery
After surgery, your child will spend a few days in
the hospital. He or she will be given medicines to reduce pain and anxiety.
Most children go home 2 days after surgery. Premature infants usually have to
stay in the hospital longer because of their other health issues.
The doctors and nurses at the hospital will teach
you how to care for your child at home. They will talk to you about:
- Limits on activity for your child while he or she
recovers
- Followup appointments with your child's doctors
- How to give your child medicines at home, if
needed
When your child goes home after surgery, you can
expect that he or she will feel fairly comfortable, although there may be some
short-term pain.
Your child should begin to eat better and gain
weight quickly. Within a few weeks, he or she should fully recover and be able
to take part in normal activities.
Long-term complications from surgery are rare.
However, they can include narrowing of the aorta, incomplete closure of the
PDA, and reopening of the PDA.
Living With Patent Ductus Arteriosus
Most children are healthy and live normal lives
after treatment for patent ductus arteriosus (PDA).
If your child was a full-term infant, he or she
will likely have normal activity levels, appetite, and growth after PDA
treatment, as long as there are no other
congenital
heart defects.
If your child was born prematurely, the outlook
after PDA treatment depends on other factors, such as:
- How early he or she was born
- Whether he or she has other illnesses or
conditions, such as other congenital heart defects
Ongoing Care
Children who have PDA are at slightly increased
risk for
infective
endocarditis (IE). IE is an infection of the lining of the heart, valves,
or arteries.
Your child's doctor will discuss with you whether
your child needs antibiotics before certain medical procedures to prevent IE.
According to the most recent American Heart Association guidelines, most
children who have PDA don't require antibiotics.
Key Points
- Patent ductus arteriosus (PDA) is a heart
problem that occurs soon after birth in some babies. In PDA, abnormal blood
flow occurs between two of the major arteries connected to the heart (the aorta
and the pulmonary artery).
- This happens because a blood vessel called the
ductus arteriosus doesn't close after birth as it should. When the vessel
remains open (patent), it can put strain on the heart and increase blood
pressure in the lung arteries.
- The cause of PDA isn't known. Genetics may play
a role. PDA can occur in children with otherwise normal hearts or in children
born with other heart defects.
- PDA is a relatively common
congenital
heart defect in the United States. On average, PDA occurs in about 8 of
every 1,000 full-term births and about 2 of every 1,000 premature births.
- The condition also is more common in infants who
have genetic conditions (such as Down syndrome) and infants whose mothers had
German measles (rubella) during pregnancy. PDA is twice as common in girls as
in boys.
- A
heart
murmur (an extra or unusual sound heard during the heartbeat) may be the
only sign that a baby or child has PDA. However, not all heart murmurs are
signs of PDA, and most murmurs are harmless. Some infants who have PDA may
develop signs of volume overload on the heart and excess blood flow in the
lungs.
- In full-term infants, PDA usually is first
suspected when the baby's doctor hears a heart murmur during a regular checkup.
Premature babies who have PDA may not have the same symptoms as full-term
babies. Doctors may suspect a PDA in premature babies who develop breathing
problems soon after birth.
- Tests can help confirm a diagnosis of PDA. Two
painless tests are used:
echocardiography
and EKG
(electrocardiogram).
- PDA is treated with medicines, catheter-based
procedures, and surgery. The goal of treatment is to close the PDA to prevent
complications and reverse the effects of increased blood volume. Small PDAs
often close without treatment.
- Most children are healthy and live normal lives
after treatment for a PDA. If your child was born prematurely, the outlook
after PDA treatment depends on how early he or she was born and whether he or
she has other illnesses or conditions.
- Children who have PDA are at slightly increased
risk for
infective
endocarditis, an infection of the lining of the heart, valves, or arteries.
Your child's doctor will discuss with you whether your child needs antibiotics
before medical procedures to prevent this infection. Most children who have PDA
don't require antibiotics.
Links to Other Information About Patent Ductus
Arteriosus
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