Patent Ductus Arteriosus
What is a patent ductus arteriosus (PDA)?
Patent mean "open". The ductus arteriosus is a blood vessel connecting the main vessel leading to the lungs (pulmonary artery) to the main vessel of the body (aorta).
Why does a baby have a ductus arteriosus?
Before birth, the mother and placenta take care of the oxygen needs of the fetus (baby before birth). The fetus does not need to use his/her lungs. Therefore, very little blood needs to go to the lungs to help them grow. The ductus arteriosus allows most of the blood to bypass the lungs and go the rest of the body. After birth, the baby must use his/her lungs to take in oxygen and get rid of carbon dioxide. Now, the blood from the pulmonary artery needs to go to the lungs to pick up oxygen instead of going through the ductus arteriosus. Normally after birth the ductus gradually narrows and then closes in the first few hours to days. In premature infants, especially those who have had respiratory distress syndrome, this blood vessel may stay open.
What happens if this blood vessel stays open?
Blood goes in the opposite direction through this vessel than it would in the fetus. It goes from the aorta to the lungs. In addition, there is normal blood flow from the heart to the lungs. This is too much blood into the baby's lung. Fluid in the lung increases and it makes it harder for the baby to breathe. The PDA increases the work of the heart and the baby can develop heart failure if the amount of blood flowing through the PDA is large. How will doctors know if my baby has a PDA?
Your doctors may suspect your baby has a PDA if:
- s/he needs more oxygen or help breathing when s/he should be needing less
- his/her breathing is more difficult or there is much more apnea
- the doctor or nurse hears a murmur (an abnormal noise over the heart)
- the baby's heart rate increases and/or the pulse changes
If a PDA is suspected, your baby will probably have an echocardiogram. In this test sound waves are used to give a picture of the baby's heart and determine the amount of blood flow through the PDA. It is painless and is similar in principle to the ultrasound that many women have when they are pregnant.
How is a PDA treated?
If the ductus is very small and there is only a tiny amount of blood flowing through it, your baby's doctors may wait to see if it closes on its own.
The most common drug used to treat a PDA is indomethacin. It causes the ductus to narrow. As the ductus narrows, less blood flow can go through it. Indomethacin may also cause your baby to make less urine. Sometimes more than one course of indomethacin is needed to close a ductus. Some physicians use ibuprofen instead of indomethacin.
Your doctor might also decide to decrease the amount of fluid that your baby is receiving while the PDA is open.
Occasionally another drug called a diuretic is given to decrease the fluid in the lungs and increase the amount of urine that your baby makes.
What happens if medical treatment doesn't work?
If the ductus will not close with medication, or if your baby's doctors do not think your baby should have these drugs, the PDA may be tied off (ligated) surgically through an incision in the baby's chest.
Does my baby have a heart malformation (abnormal development)?
It is very rare for a baby to also have a heart malformation. A PDA in a premature baby is not considered a malformation. The echocardiogram will determine if your baby's heart is otherwise normal.
Will the PDA come back?
Sometimes drugs only close the ductus for hours or a few days. A second course may be needed, or surgery may be required. However, once the baby is over his/her problems of prematurity and the PDA has gone away, it will not come back later in life.
What if the ductus arteriosus is open at the time my baby goes home?
If the ductus arteriosus has not closed by the time your baby goes home, it will need to be followed by the baby's doctor. Frequently the PDA will close on its own within several months after birth. Your child's doctor may refer you to a pediatric cardiologist (a doctor who cares for children with heart problems).
What happens if the PDA does not close?
If your baby is not growing well, or there is evidence that the PDA is making your baby sick, the PDA will probably need to be closed. However, if the baby is growing well and thriving, then nothing is done until approximately one year of age.
How is the PDA closed?
There are two common ways that a PDA is closed:
- Surgical closure - A small 1-2 inch incision is made in the area underneath the baby's armpit. The surgeon is able to see the PDA through the incision and close it with a metal clip or suture material.
- Coil occlusion - One or more small coils (small curly pieces of metal) are placed into the PDA by a cardiologist during a procedure known as a cardiac catheterization. The catheterization is done in a room very much like an operating room. Long flexible tubes (known as catheters) enter the body through blood vessels in the groin.
The catheters are then moved by the cardiologist to the area of the PDA where the coils are placed. Your child's doctor and you will choose the method that is best for your baby. The decision is made based on the size of your baby and any other associated medical problems.
What are the benefits of surgical closure?
The surgery is very quick and easy. There is little blood loss and hospital stay is short. When a PDA is closed in this manner there is a very high likelihood that it will stay closed for life.
What are the disadvantages of surgical closure?
There is the risk of anesthesia (the medicine used to make you sleep) while the operation is being done. In addition, your baby will have a scar, though usually small.
What are the benefits of coil occlusion?
There is no scar from the procedure. The baby usually leaves the hospital the next day and the recovery time is very quick. The procedure is done while the baby is sleeping, but general anesthesia is not usually used.
What are the disadvantages of coil occlusion?
In a small number of cases the PDA will not be completely closed. A small leak may remain. In addition, there is radiation exposure (though small) during the procedure. It is rare, but there is a chance that during the procedure the coils would not stay in the PDA, but become lodged somewhere else in the body. If this happens the baby may require additional surgery to remove the coils.