Patent Ductus Arteriosus
Patent ductus arteriosus (PDA) is the term that describes failure of a blood vessel present before birth (the ductus arteriosus) to close in the early days after birth. This vessel is present in the unborn child to allow blood to bypass the lungs since the lungs are not needed to provide the blood with oxygen prior to birth (the mother's placenta supplies the baby's blood with oxygen before birth). After the birth this blood vessel normally closes off and turns into a fibrous band of tissue that disappears. This process occurs because of a reaction in the walls of the ductus that cause it to close when it is exposed to high levels of oxygen in the first 24 hours of life. If this vessel does not close after birth, pressures in the pulmonary arteries may become very high (pulmonary hypertension) and lung damage can occur that can be permanent.
One identified cause of PDA is a mother's exposure to the virus rubella. Most of the time no cause of a PDA can be identified. It does occur frequently in prematurely-born infants whose lungs are not oxygenating the blood sufficiently to expose the walls of the ductus to high oxygen levels. Babies with a patent ductus arteriosus will often have a hoarse cry, a cough, pneumonia, heart failure with difficulty breathing, and poor weight gain. They may perspire when they are feeding and have a rapid heart and respiratory rate.
Patent ductus arteriosus is a common condition of prematurely born children, but it is not considered a congenital defect in those children; rather it is typically a transient effect of their early birth and lung immaturity. It occurs as a congenital heart defect in 8 of 1000 live births of full-term children and makes up 5-10% of all congenital heart defects. Girls are 2-3 times more likely to have a patent ductus arteriosus than are boys.
Common Associated Conditions
PDA occurs as a single defect in some children, and it is a component of many other heart conditions.
Short-term Treatment and Outcomes
Babies with patent ductus arteriosus often have a heart murmur that indicates the condition is present. An echocardiogram and chest x-ray will be done, and in some cases magnetic resonance imaging (MRI) will also be helpful. A drug called indomethicin will be given to the baby through the vein to see if this drug will affect the walls of the ductus arteriosus and cause it to close without any other treatment being necessary. If the defect does not close by age 1-2 years, surgery will be done to close off the vessel (called ligation surgery).
Long-term Treatment and Outcomes
Children with significant heart surgery histories have to take antibiotics when they have dental work because the bacteria in the mouth can be released into the blood stream and cause an infection in the heart (endocarditis). If the baby has no other conditions besides the PDA the outlook from this condition is extremely favorable.
Congestive heart failure is a common complication of an untreated patent ductus arteriosus because of the extra blood flow to the lungs. The child will also have heart enlargement (cardiomegaly) from the extra work the heart has to do. A serious complication of uncorrected patent ductus arteriosus would be considerable lung damage (called pulmonary vascular obstructive disease) that then causes the flow of blood through the heart and ductus to reverse from a left-to-right blood flow to right-to-left flow. Thus blood that lacks oxygen would flow to the body. This flow reversal is called Eisenmenger's syndrome, and once it occurs it is not correctable; a heart-lung transplantation would be the only treatment. Other complications of untreated PDA include infection of the heart (endocarditis), weak heart function (congestive heart failure), and slow growth.
Implications for Children's Development
If the child's lungs have not been significantly damaged prior to the corrective treatment, the outlook for the child with PDA is very favorable. There should be no restriction on activities or negative effects on the child's development.
For more information, including resources for parents and general information about congenital cardiac conditions, visit the following websites:
- Medline Plus
Lasting Imprint of MN: Lasting Imprint exists to create a supportive community that will inspire people to join in the fight against congenital heart defects through education, research, and assistance to heart families.