Patent Ductus Arteriosus (PDA)
A blood vessel that fails to close after birth
Quick Facts
- Type: Congenital heart condition
- What it is: An open fetal blood vessel (ductus arteriosus)
- More common in: Premature infants
- Treatment: Monitoring, medication, or closure procedure
Overview
Before birth, a blood vessel called the ductus arteriosus connects two major arteries leaving the heart, the aorta and the pulmonary artery. This vessel is a normal part of fetal circulation and usually closes within the first days of life. In patent ductus arteriosus (PDA), the vessel stays open after birth, allowing extra blood to flow into the lungs and making the heart work harder.
PDA is a type of congenital heart condition and is especially common in babies born prematurely. A small PDA may cause no problems and is sometimes found only by chance when a doctor hears a heart murmur. A larger one allows a greater amount of blood to recirculate through the lungs, which makes the heart work harder and can strain the heart and lungs over time, so it usually needs treatment. How the PDA is managed depends a great deal on whether the baby was born early or at full term and on the size of the vessel.
Symptoms
A small PDA may cause no symptoms and be found only because of a heart murmur. A larger PDA tends to cause noticeable problems, often in infancy.
- A continuous heart murmur heard with a stethoscope
- Fast breathing or shortness of breath
- Poor feeding and slow weight gain in infants
- Tiring easily, especially during feeding or activity
- Rapid heartbeat
- Frequent respiratory infections
Symptoms of a large PDA can include breathing difficulty and signs of heart strain, which need medical evaluation.
Causes
PDA occurs when the normal process that closes the ductus arteriosus after birth does not happen.
- Prematurity: The most important factor; the vessel is more likely to stay open in babies born early.
- Genetic factors: PDA can run in families and occur with some genetic syndromes.
- Conditions during pregnancy: Rubella infection during pregnancy and being born at high altitude increase the risk.
In premature infants, immaturity of the vessel and lungs makes spontaneous closure less likely.
Risk Factors
- Premature birth
- A family history of heart defects
- Rubella (German measles) infection during pregnancy
- Birth at high altitude
- Certain genetic conditions, such as Down syndrome
Diagnosis
A PDA is often suspected when a doctor hears a distinctive continuous murmur. Tests confirm it and assess its size.
- Echocardiogram: The main test, showing the open vessel and the direction and amount of blood flow.
- Chest X-ray: Can show an enlarged heart or changes in the lungs.
- Electrocardiogram (ECG): Records the heart's electrical activity and can show strain on the heart.
- Oxygen monitoring: Helps assess how the PDA is affecting the baby's circulation.
Treatment
Treatment depends on the baby's age, the size of the PDA, and the symptoms it causes.
- Watchful waiting: Small PDAs that cause no problems may close on their own and can be monitored.
- Medication: In some premature infants, certain medicines can help the vessel close.
- Catheter closure: A device placed through a blood vessel can seal many PDAs without open surgery.
- Surgery: An operation to close the vessel is used when a catheter procedure is not suitable.
Closing a significant PDA usually relieves symptoms and protects the heart and lungs, with excellent long-term outcomes. If a large PDA is left untreated over many years, it can lead to an enlarged, overworked heart and to high pressure in the lung arteries, called pulmonary hypertension, which is harder to reverse once it develops. There is also a small risk of infection of the heart lining (endocarditis) with an open PDA. For these reasons, doctors recommend closing PDAs that are causing problems or are large. After successful closure, most children and adults have a normal life expectancy and need little or no further treatment, though they may have follow-up visits to confirm the heart is working well.
When to See a Doctor
See a doctor if an infant feeds poorly, breathes rapidly, tires easily, or is not gaining weight, or if a heart murmur has been heard. Seek prompt medical attention for:
- Severe or worsening breathing difficulty
- Bluish color of the skin or lips
- Very fast breathing with feeding problems
- Unusual sleepiness or poor responsiveness in a baby
Frequently Asked Questions
Can a patent ductus arteriosus close on its own?
Yes. Small PDAs, particularly in full-term babies, often close by themselves in the early weeks of life. Larger ones, or those in very premature infants, are less likely to close on their own and may need medication or a procedure.
Why is PDA more common in premature babies?
The ductus arteriosus is more likely to remain open in babies born early because the vessel and lungs are still immature. As a result, PDA is a frequent finding in premature infants and is monitored closely.
How is a PDA closed without surgery?
Many PDAs are sealed using a small device delivered through a thin tube (catheter) inserted into a blood vessel, avoiding open-heart surgery. In some premature infants, medication can help the vessel close instead.
Is a small PDA dangerous?
A small PDA often causes no symptoms and may close on its own, posing little risk. A larger PDA can strain the heart and lungs over time and usually needs treatment. Regular check-ups help track its size and effects.
What happens if a PDA is left untreated?
A small, silent PDA may never cause trouble. A larger untreated PDA can lead to heart strain, lung problems, and over many years high pressure in the lung arteries. Treatment is recommended when the PDA is significant.
References
- Centers for Disease Control and Prevention (CDC). Patent Ductus Arteriosus (PDA).
- Mayo Clinic. Patent ductus arteriosus (PDA).
- MedlinePlus, U.S. National Library of Medicine. Patent ductus arteriosus.