Patent ductus arteriosus an overview

Patent ductus arteriosus (PDA) is a congenital heart disease. A PDA is a persistent connection between the aorta and the pulmonary artery. This connection is called the ductus arteriosus and is normally present before birth. In most babies, the vessel closes within a few hours to days after birth. In some children, this vessel fails to close.The Ductus ArteriosusThe ductus arteriosus is a blood vessel. It connects the aorta and the pulmonary artery. Before birth:· It allows blood to flow through the baby's body without passing through the lungs.· The baby gets oxygen and nutrients from the mother through the placenta and umbilical cord before birth.After birth, as a baby begins to breathe on his or her own: · Air replaces fluid in the baby's lungs.· The pulmonary artery begins to carry oxygen-poor (blue) blood to the lungs to pick up oxygen.· The aorta begins to carry oxygen-rich (red) blood to the body.· The ductus arteriosus is no longer needed, and it usually closes within a few hours to days after birth. Patent Ductus ArteriosusThe ductus arteriosus becomes a PDA if it does not close as it should. Blood can still travel through a PDA.

A PDA can occur in:· Children with otherwise normal hearts· Children born with other types of congenital heart disease. If your baby is born with a PDA but has an otherwise normal heart, the PDA may need to be treated. But if your baby is born with certain other heart defects (in addition to a PDA) that cause inadequate blood flow from the heart to the lungs or the body, the PDA may be needed to maintain blood flow and oxygen levels temporarily. Doctors sometimes use medication to keep the ductus open after birth until corrective surgery for the heart defect(s) can be performed. About 3,000 infants are born with PDA each year in the United States. It is more common in premature infants (babies born too early), but does occur in full-term infants. Premature babies with PDA are more vulnerable to its effects. PDA is twice as common in girls as in boys.Effects of PDAA PDA allows too much blood to pass through your baby's lungs. Some oxygen-rich (red) blood traveling in the aorta out to the body flows through the PDA back to the lungs. This extra blood flowing to the lungs overloads the lungs and the heart. The larger your baby's PDA is, the greater the amount of extra blood that passes through his or her lungs.

A small PDA might not cause any symptoms, while a larger PDA is likely to cause symptoms.PDA can cause congestive heart failure:· The left side of your baby's heart becomes enlarged and weakened from having to work so hard pumping the extra blood that is returning from the lungs.· The lungs become congested with fluid from the extra blood passing through them.In addition to congestive heart failure, PDA can lead to:· Pulmonary vascular disease--damage to the arteries in the lungs due to the extra blood flow. The arteries become stiff and thickened, making it harder for blood to flow through them (pulmonary vascular resistance). This change becomes irreversible over time.· Bacterial endocarditis--an infection of the lining of the heart, valves, or arteries. In the case of PDA, the shunting of blood from the aorta to the lungs irritates the lining of the left pulmonary artery where the PDA connects. This irritation of the artery lining makes it easier for bacteria in the bloodstream to collect and grow there. Fortunately, a number of treatments are available for PDA if the PDA does not close on its own. Treatment often does not require surgery, but can be through medicine or catheter-based. Once a PDA is closed, most children live healthy lives To better understand PDA, go to the section on "How the Heart Works" with an image of a normal heart and a heart with PDA.

How the Heart WorksYour child's heart is a muscle about the size of your child's fist. It works like a pump and beats about 100,000 times a day.The heart has 2 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 4 chambers and 4 valves, and is connected to various blood vessels. Veins are the blood vessels that carry blood from the body to the heart, while arteries are the vessels that carry blood away from the heart to the body.
Heart Chambers

The heart has 4 chambers or "rooms"--2 on the left side of the heart and 2 on the right.· The atria (AY-tree-uh) are the 2 upper chambers that collect blood as it comes into the heart.· The ventricles (VEN-trih-kuls) are the 2 lower chambers that pump blood out of the heart to the lungs or other parts of the body. Heart ValvesFour valves control the flow of blood from the atria to the ventricles and from the ventricles into the 2 large arteries connected to the heart.The 4 valves are:· The tricuspid (tri-CUSS-pid) valve in the right side of the heart, between the right atrium and the right ventricle· The pulmonary (PULL-mun-ary) valve in the right side of the heart, between the right ventricle and the entrance to the pulmonary artery that carries blood to the lungs· The mitral (MI-trul) valve in the left side of the heart, between the left atrium and the left ventricle· The aortic (ay-OR-tik) valve 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 backwards. When your heart's valves open and close, they make the familiar "lub-DUB" or "lub-DUPP" sounds that your doctor can hear using a stethoscope. · The first sound is made by the tricuspid and mitral valves closing at the beginning of systole (SIS-toe-lee). Systole is when the heart contracts, or squeezes, and pumps blood out of the heart.· The second sound is made by the aortic and pulmonary valves closing at the beginning of diastole (di-AS-toe-lee).

Diastole is when the heart relaxes and fills with blood.ArteriesThe arteries are the 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 to the heart muscle, which must have its own blood supply to function.Veins The veins 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 vena cava is a large vein that carries oxygen-poor blood from the body back to the heart.

What Causes Patent Ductus Arteriosus?The cause of PDA is not known. Heredity may play a role. A defect in one or more genes or a chromosome abnormality could prevent the ductus arteriosus from closing normally after birth. PDA is more common in: · Premature infants (babies born too early)· Infants with genetic abnormalities such as Down syndrome· Infants whose mother had German measles (rubella) during pregnancy.
What Are the Signs and Symptoms of Patent Ductus Arteriosus?A heart murmur may be the only sign that a baby has PDA. A heart murmur is an extra or unusual sound heard during the heartbeat.Some infants may develop symptoms of congestive heart failure. This is due to too much blood flowing through the lungs, which also overworks the heart. Symptoms may include:· Fast breathing, working hard to breathe, or shortness of breath· Poor feeding and poor weight gain· Tiring easily· Sweating with exertion (such as while feeding).

How is Patent Ductus Arteriosus Diagnosed?Your child's doctor will take a family and medical history, do a physical examination, and order several tests to diagnose your child's PDA.Infants born with a large PDA may have symptoms of congestive heart failure within the first few months of life. They are usually diagnosed at that time (even earlier if the baby is premature). Infants with a small PDA may not be diagnosed until they are older. If your child's doctor hears a heart murmur and suspects that it is due to a congenital heart defect, he or she will refer your child to a pediatric cardiologist. A pediatric cardiologist is a doctor who specializes in diagnosing and treating heart problems in children. Physical ExaminationDuring the physical examination, the doctor will: · Listen to your child's heart for a heart murmur· Look for signs of congestive heart failure. TestsSeveral painless tests are used in diagnosing PDA.Echocardiogram. The echocardiogram is the most commonly used test to confirm that there is a PDA. This test uses sound waves to create a picture of the heart. It is used to:· Show movement of blood through the heart· Show how large the PDA is· Check for other congenital heart defects· Show if the chambers of the heart are enlarged.Other TestsChest x-ray. This test takes a picture of the heart and lungs. It can show if the heart is enlarged or if there is fluid in the lungs. In older children, the x-ray is usually normal, so an echocardiogram is needed to show the PDA.Electrocardiogram (EKG or ECG).

This test can:· Measure the rate and regularity of the child's heartbeat· Show abnormal heart rhythms· Show if chambers in the heart are enlarged.

How is Patent Ductus Arteriosus Treated?The goals of treatment are to:· Close the PDA· Prevent the development of complications, including pulmonary vascular disease and bacterial endocarditis· Treat the symptoms of congestive heart failure, if present.Small PDAs often close without treatment. Treatment is needed if your child's PDA: · Is large· Is causing your child to have symptoms· Does not close on its own by the time your child is 12 years old.

Types of TreatmentTreatments for PDA include:· Medications· Extra nutrition · Catheter procedures· Surgery.Your child's doctor will discuss treatment options with you and will consider your family's preferences when making treatment decisions. MedicationsMedications are given to help the PDA close and to treat symptoms of congestive heart failure.· Indomethacin is a drug that helps close a PDA in premature infants. It does not usually work in full-term infants. It works by stimulating the PDA to constrict or tighten, closing the connection.· Medications used to control symptoms of congestive heart failure include:o Digoxin to help the heart pump the extra amount of blood o Diuretics to treat the buildup of fluid in the lungs and body. · Antibiotics are given before dental work and certain procedures or surgery to prevent endocarditis.Extra NutritionBabies who are born prematurely often need extra nutrition (more food and calories) to help them grow. Babies with a large PDA may also need extra food, even if they were not born prematurely. Your doctor may recommend giving your baby high-calorie formula or breast milk. Tube feedings are another way to give your baby extra food. Food is given through a small tube through the nose into the stomach. The tube feedings can add to or take the place of bottle feedings.Catheter ProceduresCatheters are thin, flexible tubes used in cardiac catheterization. Catheter procedures are often 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 is sometimes done on a small PDA to prevent the risk of bacterial endocarditis.

Closure of a PDA using a catheter is often done on an outpatient basis. You will most likely be able to take your child home the same day the procedure is done. During the procedure:· Your child will be sedated or given general anesthesia, so he or she will sleep through the procedure and not feel any discomfort.· The doctor will place a catheter in a large blood vessel in the groin and guide it to your child's heart.· A small metal coil or other blocking device will be placed in the ductus arteriosus to stop blood flow through the vessel.Catheter procedures:· Do not require the child's chest to be opened· Let the child recover quickly.Complications of catheter procedures are rare and short term. They can include bleeding, infection, and movement of the blocking device from where it was placed.SurgerySurgery may be done when:· A premature or full-term infant develops symptoms and is too small to have a catheter procedure· Surgery is planned for a related congenital heart defect. ·

The PDA does not close by the catheter procedureSurgery can be done after 6 months of age in infants who do not show symptoms. Doctors sometime perform surgery on small PDAs to prevent the risk of bacterial endocarditis. The operation is done under general anesthesia so that your child will sleep and not feel any pain. The surgeon will:· Make a small cut between your child's ribs to reach the PDA· Close the PDA with stitches. Complications of the surgery are rare and short term. They can include hoarseness, a paralyzed diaphragm, infection, bleeding, or fluid buildup around the lungs.After SurgeryAfter surgery, your child will spend a few days in the intensive care unit or in a regular hospital room. Most children go home 2 days after surgery. While in the hospital, your child will be given medications to reduce pain or anxiety. 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 medications at home.Long-term complications from treatment are rare. They can include narrowing of the aorta, incomplete closure of the ductus, or reopening of the ductus.
Living with Patent Ductus Arteriosus

Most children are healthy and live normal lives after treatment for a PDA. · If your child was not born prematurely, he or she is expected to have normal activity levels, appetite, and growth after PDA treatment, in the absence of other congenital defects. · If your child was born prematurely, the outlook after PDA treatment depends on:o How early he or she was borno Whether he or she has other illnesses or conditions, such as other congenital heart defects.Recovering from Surgery for PDA

When your child goes home after surgery, you can expect that:· Your child will feel fairly comfortable, although he or she may have some pain temporarily.· Your child should begin to eat better and gain weight quickly. · Within a few weeks, your child should be fully recovered and able to participate in normal activities. Medical Care Needs Children with a PDA have an increased risk for bacterial endocarditis. To prevent this infection:· Your doctor will give your child antibiotics before dental work and certain procedures.· It is important to take good care of your child's teeth. He or she should have regular dental care to prevent decay and help reduce the chance of infection.· Once the PDA is closed, your child will not need antibiotics before dental work or surgical procedures.
Summary·

Patent ductus arteriosus (PDA) is a persistent connection between the aorta and the pulmonary artery. This connection is called the ductus arteriosus and is normally present before birth. In most babies, the vessel closes within a few hours to days after birth. The ductus arteriosus becomes a PDA if it does not close as it should.· PDA is more common in premature infants, but it can happen in full-term infants. It is twice as common in girls as in boys. · The cause of PDA is not known. Heredity may play a role. PDA can occur in children with otherwise normal hearts or in children born with other heart defects. · With a PDA, too much blood passes through the lungs, overloading the lungs and heart. The heart must work harder than usual to pump the extra blood. This can cause congestive heart failure, in which the heart enlarges and weakens and fluid (congestion) builds up in the lungs.· PDA can lead to poor growth, damage to the arteries in the lungs due to the extra blood flow, and bacterial endocarditis. · A heart murmur may be the only sign that a baby or child has a PDA. · Some infants may develop symptoms of congestive heart failure, such as fast breathing, poor feeding and poor weight gain, tiring easily, and sweating.· Children with a large PDA are usually diagnosed within the first few months of life. Children with a small PDA may not be diagnosed until they are older. · The echocardiogram is the most commonly used test to confirm that there is a PDA. · A small PDA sometimes closes without treatment. But if a PDA is large or does not close on its own by the time the child is 12 years old, it should be repaired. · Treatments for PDA include medication, extra food, procedures using catheters, and surgery.· After closure of the PDA, most children grow normally and live healthy lives.