Patent Ductus Arteriosus (PDA)

What is Patent Ductus Arteriosus- Definition

PDA is a blood vessel that constantly remains present in an open state between the two major blood vessels leading from the heart. This opening called the ductus arteriosus is a normal part of a child's blood circulation system present before birth but generally gets closed soon by itself after the child is born. In case it stays open, it is referred as a PDA.

A small PDA frequently does not cause problems and might never necessitate treatment. But, a larger PDA, if left untreated, can lead to poorly oxygenated blood flow in the wrong direction, failing the heart muscle and leading to heart failure accompanied by other complications.

Patent Ductus Arteriosus Symptoms

PDA symptoms differ with the size of the defect and depending on the state of the newborn child – if the child is born after full-term or is premature. A small PDA might not demonstrate signs or symptoms and may remain unnoticed, even if adulthood is achieved. On the contrary, a large PDA can show features of heart failure immediately after birth.        

A doctor might first suspect a heart defect during a regular check-up after hearing a heart murmur while listening to the newborn's heart through a stethoscope.

Patent Ductus Arteriosus Causes

Congenital heart defects develop from early problems in the heart's development, but often, there’s no clear cause. However, it is suggested that genetic factors might contribute to its cause.

Before birth, a blood vessel link between the two chief blood vessels leaving from the heart — the aorta and pulmonary artery — is essential for the fetus's blood circulation. The ductus arteriosus turns away blood from the fetus's lungs during their developmental stage while the fetus receives oxygen from the mother's circulatory system.

After birth, the ductus arteriosus usually gets closed in a span of two or three days, but in premature infants, the link frequently takes more time for its self-closure. If the link still stays, it is known as a PDA. This unusual opening causes excess blood to flow to the child's lungs and heart. If left untreated, it may lead to elevated blood pressure in the child's lungs and subsequently, enlargement and weakening of the heart.

Patent Ductus Arteriosus Risk factors

Risk factors for occurrence of a PDA include:

  • Premature birth: PDA happens more frequently in children born pre-maturely vs. children born full-term.
  • Family and genetic disorders: Heart defects running in families or prevalence of genetic conditions like Down’s syndrome elevates the risk of PDA occurrence.
  • Rubella infection during pregnancy: If a mother gets a German measles’ infection during pregnancy, there is an elevated risk of heart defects in the child. The Rubella virus navigates the placenta and expands out via the circulatory system of the fetus, causing damage to the blood vessels and organs including the heart.
  • Being born at a high altitude: Children born in areas located 10,000 feet above sea level have an elevated risk of a PDA versus children born at normal altitudes.
  • Being female.

Patent Ductus Arteriosus and pregnancy

Most women having a minor PDA can bear pregnancy minus problems. On the contrary, if a larger PDA is present, complications such as heart failure, arrhythmias or pulmonary hypertension can occur and elevate complications’ risk during pregnancy. Pregnancy should be evaded, if the female has Eisenmenger syndrome, as it can be dangerous.

If an individual has a heart defect, or got it fixed in the past, should consult a doctor before family planning. In some instances, pre-conceptive meetings with hereditary cardiology experts are needed. Some heart medications can be responsible for causing serious problems in a developing baby and it might be necessary to stop or adjust the medications before one becomes pregnant.

Patent Ductus Arteriosus Prevention

There is no sure way to prevent having a child with a PDA. However, it is critical to do everything imaginable to have a healthy pregnancy. Following are some basic pre-requisites:

  • Try to find prompt prenatal care, even before onset of pregnancy
  • Quitting smoking, reducing stress, stopping birth control and so on are things to discuss with the doctor before getting pregnant.
  • Also, inform the doctor about any current medication.
  • If the mother has a family history of heart defects or other genetic disorders, she should consider talking with a genetic counsellor before becoming pregnant.
  • Eat a healthy diet: Include a vitamin supplement that contains folic acid.
  • Exercise regularly: Work with the doctor to develop an exercise plan that is right for herself.
  • Avoid consuming risky substances: These include consumption of alcohol, tobacco products and illegal drugs. Also, avoid hot tubs and saunas.
  • Avoid infections: Update vaccinations before becoming pregnant. Certain types of infections can be harmful to a developing baby.
  • Keep diabetes under control. If she has diabetes, work with the doctor to manage the condition before and during pregnancy.

Patent Ductus Arteriosus Diagnosis

The doctor might doubt that a child has a PDA based on his/her heartbeat. PDA can cause a heart murmur that the doctor can hear through a stethoscope.

If the doctor suspects a heart defect, he or she might request one or more of the following tests:           

  • Echocardiogram: Sound waves produce images of the heart that can help the doctor identify a PDA to see if the heart chambers are enlarged and judge how well the heart is pumping. This test also helps the doctor evaluate the heart valves and detect other potential heart defects.
  • Chest X-ray: An X-ray image helps the doctor see the condition of the child's heart and lungs. An X-ray might reveal conditions other than a heart defect, as well.
  • Electrocardiogram/ECG: This test records the electrical activity of the heart that can help the doctor diagnose heart defects or rhythm problems.
  • Cardiac catheterization: This test is not generally needed for diagnosing a PDA alone but it might also check the presence of other inborn heart defects found in an echocardiogram or if a catheter procedure is under consideration for PDA treatment. A catheter is a thin, flexible tube that is inserted into a blood vessel at the child's groin or arm and guided through it into the heart. Through catheterization, the doctor may be able to carry out procedures to close the PDA.

Patent Ductus Arteriosus Treatment

Treatments for PDA depend on the age of the person being treated. Options might include:

  • Watchful waiting: A PDA mostly closes on its own in a premature baby. The doctor will monitor the baby's heart to ensure the open blood vessel is getting closed suitably. For babies born at full-term, children and adults with a small PDA that is not harmful or causing symptoms, mere monitoring is needed.
  • Medications: In babies born pre-maturely, non-steroidal anti-inflammatory drugs (NSAIDs) might be used to help PDA closure. However, NSAIDs cannot be helpful in full-term babies, children or adults.
  • Surgical closure: If medications are not helping and the condition of your child is severe or is worsening, surgery might be recommended. A surgeon makes a small incision between the child's ribs and reaches the child's heart and mends the open duct using stitches or clips.
    • After Surgery: Child will stay in the hospital for a number of days under observation. It generally requires a few weeks for a child for complete recovery. In some occasions, surgical closure might also be suggested for adults with a PDA which is causing health problems. Possible risks of the surgery include roughness, hemorrhage, infection and an immobilized diaphragm.
  • Catheter procedures: Babies born prematurely are too minor for performance of catheter procedures. However, if the child is not having PDA-related health problems, the doctor might suggest to wait until the baby is of age suited to perform a catheter procedure to correct the PDA. Catheter procedures can also be used to treat children born at full-term, young children and adults. In a catheter procedure, a thin tube is inserted into a blood vessel in the groin and threaded up to the heart. Through the catheter, a plug or coil is inserted to close the ductus arteriosus.

Patent Ductus Arteriosus Follow-up Care

If a patient has PDA, even if he/she had surgery as a child, he/she may be at risk of developing complications as an adult. So it is vital to have lifetime follow-up care, especially if he/she had corrective heart surgery. This follow-up care could range from a simple periodic checkup or regular testing for complications. The important thing is to discuss the patient’s care plan with his/her doctor and make sure he/she follows all of the doctor's recommendations. Preferably, a trained cardiologist having expertise in congenital heart defects will manage such patient’s care. Discuss the patient’s heart disease with the doctors before having a surgical procedure. Sometimes the surgery or anesthesia can affect the heart.