Patent ductus arteriosus (PDA)
Patent ductus arteriosus (PDA) is a congenital heart defect that occurs when the ductus arteriosus, a blood vessel connecting the aorta and pulmonary artery, remains open after birth instead of closing as it typically should. This condition can lead to excessive blood flow to the lungs and heart, potentially causing complications such as pulmonary hypertension and heart failure. PDA is more prevalent in premature infants and is particularly common among those with certain genetic disorders or maternal infections during pregnancy, such as rubella. Symptoms can vary widely; while some infants may show no signs, others may experience rapid breathing, poor growth, or tiring easily during feeding.
Diagnosis usually involves listening for heart murmurs and may include chest X-rays and echocardiograms. Treatment options depend on the size of the PDA and the infant's overall health; small PDAs often close on their own, while larger ones may require catheterization or surgery to close. Those who undergo successful treatment typically have a good prognosis and do not face significant long-term health issues. Although there is no definitive way to prevent PDA, maintaining a healthy pregnancy can reduce the risk.
Patent ductus arteriosus (PDA)
Patent ductus arteriosus (PDA) is a common congenital (at birth) heart defect. Prior to birth, the fetus does not need blood to travel through the lungs for oxygenation. At this point, the fetus receives oxygen from the mother's circulation. The ductus arteriosus (a major blood vessel connecting the aorta to the pulmonary artery) remains patent, or open, to allow blood to move away from the lungs. A few days after birth, the hole typically narrows and closes, so the new baby's blood can travel through the lungs. When the hole does not close, PDA occurs. The hole allows too much blood to circulate into the infant's lungs and heart. This can increase the risk for heart problems and may cause pulmonary hypertension (high blood pressure in the lungs).
Causes
PDA is more common in girls than boys, specifically in premature infants and especially in those with neonatal respiratory distress syndrome. Neonatal respiratory distress syndrome is a breathing disorder common in premature infants because their lungs are underdeveloped. The condition is very rare in full-term infants.
PDA can affect infants with genetic disorders such as Down syndrome. Infants whose mothers had rubella (German measles) during pregnancy are at a high risk for the condition. PDA also is common in infants with congenital heart defects such as transposition of the great vessels or pulmonary stenosis.
Although some infants are at a higher risk than others for developing the condition, the exact cause of PDA is not known. Genetics and family history can put some infants at risk. Parents with a family history of heart defects and genetic conditions have a higher risk of having a child with PDA. In addition, environmental factors could be to blame. Infants born at altitudes higher than 10,000 feet (3,048 meters) are at a higher risk of developing PDA than infants born at lower altitudes.
Symptoms
While no test exists to determine the presence of PDA, doctors usually can detect heart issues soon after birth when listening to the infant's heart with an instrument called a stethoscope. After hearing a heart murmur, doctors use chest x-rays and echocardiogram (an ultrasound that tests the heart's function) to diagnose PDA.
Some infants do not show any signs of having PDA. Some common symptoms include rapid or irregular breathing or pulse; shortness of breath; feeding issues such as sweating while feeding; sweating while crying; exhaustion and tiring easily; and poor growth.
These symptoms vary according to the size of the PDA and whether the infant was premature or full-term when he or she developed PDA. Smaller holes may not cause any signs or symptoms. They rarely cause major complications and may go undetected until the child reaches adulthood.
Larger holes may cause the heart to enlarge and weaken and eventually lead to heart failure very soon after birth. Pulmonary hypertension may occur. This is caused by too much blood circulating through the circulatory system. In rare cases, PDA can cause Eisenmenger syndrome, a serious type of pulmonary hypertension that cannot be reversed. PDA also may cause endocarditis (heart infection).
Women who have PDA and get pregnant may face serious issues during pregnancy. They are at a higher risk for certain complications such as arrhythmia (abnormal heartbeat), heart failure, and pulmonary hypertension.
Treatment
Small holes may not cause any issues and may not even need treatment. Small holes typically close on their own after a few weeks. If this does not happen, the PDA will need to be closed by catheterization. During catheterization, catheters (long thin tubes) are inserted into blood vessels in the leg that reach the heart and PDA. A coil is then inserted through the catheter to plug up the PDA.
Sometimes, open-heart surgery is needed to close the PDA. During surgery, the surgeon will cut into the chest to expose the PDA. The hole is either tied closed with sutures or squeezed closed with a metal clip. It takes a few weeks for a patient to recover from surgery, and some risks such as bleeding and infection exist.
Premature infants typically need medication to help close the PDA. Some medications include nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen or indomethacin. These medications should be administered a few days after birth to block the hormones in the body that prevent the PDA from closing. If the medication does not work, catheterization or surgery may be required. Medications are used to treat PDA only in premature infants.
After the PDA is closed (either by catheterization, surgery, or medication) and the patient recovers, he or she usually does not have any other health complications or physical restrictions. The long-term prognosis for those with PDA is very good. No further medications or additional procedures generally are needed.
Prevention
There is no way to completely prevent having a child born with PDA. Pregnant women can take some steps to ensure they have a healthy pregnancy, which can help lessen chances they will have a child with PDA. Some of these include
Avoiding smoking, drinking alcohol, and taking drugs
Alleviating stress
Eating a healthy diet
Exercising
Getting vaccinated
Women who have heart defects or genetic conditions—or if these disorders run in their families—should consult a physician or genetic counselor prior to the pregnancy.
Bibliography
Kim, Luke K., and Jeffrey C. Milliken. "Patent Ductus Arteriosus (PDA)." Medscape. WebMD LLC. 16 Sept. 2015. Web. 14 Feb. 2016. http://emedicine.medscape.com/article/891096-overview
"Patent Ductus Arteriosus." MedlinePlus. U.S. National Library of Medicine. Web. 14 Feb. 2016. https://www.nlm.nih.gov/medlineplus/ency/article/001560.htm
"Patent Ductus Arteriosus (PDA)." American Heart Association. American Heart Association, Inc. Web. 14 Feb. 2016. http://www.heart.org/HEARTORG/Conditions/CongenitalHeartDefects/AboutCongenitalHeartDefects/Patent-Ductus-Arteriosus-PDA‗UCM‗307032‗Article.jsp#.Vr3r3Pnyu70
"Patent Ductus Arteriosus (PDA)." Mayo Clinic. Mayo Foundation for Medical Education and Research. 16 Dec. 2014. Web. 14 Feb. 2016. http://www.mayoclinic.org/diseases-conditions/patent-ductus-arteriosus/basics/definition/con-20028530
"What Is Respiratory Distress Syndrome?" National Heart, Lung, and Blood Institute. U.S. Department of Health and Human Services. Web. 14 Feb. 2016. https://www.nhlbi.nih.gov/health/health-topics/topics/rds