Patent ductus arteriosus is a heart birth defect that occurs when the normal channel between the pulmonary artery and the aorta in the fetus does not close at birth.
Often there are no symptoms, and the diagnosis is suspected based on a heart murmur the doctor hears with a stethoscope.
Premature newborns are especially susceptible to patent ductus arteriosus. They are more likely to have symptoms, including trouble breathing (especially when feeding)
Treatment with ibuprofen or indomethacin often helps to close the PDA, particularly in premature infants. If drugs are not successful, surgery may be done.
In full-term newborns, treatment with drugs is less likely to be successful, especially since these infants are usually a bit older when the diagnosis of PDA is made. Unless they have symptoms, surgical treatment is often delayed because in these infants the PDA often closes on its own.
(See also Overview of Heart Defects.)
The ductus arteriosus is a blood vessel in the fetus that connects the two great arteries leaving the heart, the pulmonary artery and the aorta (see Normal Fetal Circulation). The ductus is a short-cut that allows blood to bypass the fetus's not-yet-functioning lungs by traveling from the pulmonary artery to the aorta and out to the fetus's body. In the fetus, the venous blood arriving at the heart has received oxygen from the placenta. This oxygenated blood can be delivered to the body through the two connections of the foramen ovale and ductus arteriosus. Immediately after birth, these connections close. When the umbilical cord is cut, the fetus's placental blood flow is no longer connected across a separating membrane from the mother's blood flow. During fetal life, that membrane allows oxygen to pass into the fetus's blood and carbon dioxide to pass back to the mother's blood without the blood from the mother and fetus actually mixing. Once the cord is cut, all the newborn's oxygen must come through the newly born infant's lungs. Thus, the ductus arteriosus is no longer needed and usually closes within the first days of life. In the womb and during the first few days of life, the ductus is open. In patent ductus arteriosus (patent is a medical term that means open), the ductus stays open. When the ductus stays open after birth, the direction of flow through the ductus reverses and a left-to-right shunt develops. This means that some blood in the aorta that has already picked up oxygen from the lungs goes back through the ductus and into the pulmonary artery, which causes extra blood flow into the lungs.
A patent ductus arteriosus that is moderate or large will also cause high blood pressure in the lungs, which may eventually damage the blood vessels of the lungs. A patent ductus increases the risk of developing a serious heart infection, endocarditis.
Patent Ductus Arteriosus: Failure to Close
Doctors often suspect a patent ductus if they hear a certain kind of heart murmur while listening with a stethoscope. A heart murmur is a sound created by turbulent blood flow through narrowed or leaking heart valves or through abnormal heart structures. In older children, the murmur has been described as sounding like a washing machine. In premature infants, the heart murmur may be less distinct. The pulses are often increased in the presence of a patent ductus arteriosus, the pulse is sometimes described as bounding.
Echocardiography (ultrasonography of the heart) confirms the diagnosis.
Indomethacin or ibuprofen can be given to close a patent ductus arteriosus. These drugs are most effective if given within the first 10 days after birth and are more effective in premature newborns than in full-term ones. Several doses may be given. If the PDA does not close after several doses, surgery may be done if there are signs that the PDA is harming the lungs and heart.
In full-term newborns and infants who do not have symptoms, doctors may allow time for the PDA to close on its own before they suggest treatment.
If a PDA is still open by the time infants are 1 year of age, it is extremely unlikely to close on its own. At that time, doctors usually recommend a procedure to close the PDA to eliminate the risk of endocarditis.
In most cases, doctors close the patent ductus arteriosus by inserting a small device or coil during cardiac catheterization. During this procedure, the closure device is attached to the end of a long, thin tube (catheter). The catheter is inserted into the large vein in the groin. The catheter is carefully pushed up through the blood vessel until it reaches the heart and then advanced a little further until the tip with the device is in the ductus. Once the device is in the proper location, it is expanded to close the ductus.
Occasionally, particularly when the ductus is unusually large, doctors do surgery to close the ductus.
Children need to take antibiotics before visits to the dentist and before certain surgeries (such as on the respiratory tract), during the first 6 months after closure of the ductus. Sometimes antibiotics are needed for a longer time if surgery is unable to completely close the ductus. These antibiotics are used to prevent serious heart infections called endocarditis.
The following are some English-language resources that may be useful. Please note that THE MANUAL is not responsible for the content of these resources.
American Heart Association: Common Heart Defects: Provides an overview of common birth defects of the heart for parents and caregivers
American Heart Association: Infective Endocarditis: Provides an overview of infective endocarditis, including summarizing antibiotic use, for parents and caregivers
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