Patent Ductus Arteriosus

What is patent ductus arteriosus?

During pregnancy, there is an extra structure called the ductus arteriosus within the fetal heart. It allows blood to bypass the lungs and go straight to the descending aorta to supply oxygen rich blood to the body. This is because the fetal lungs are not needed to provide oxygen to the fetus as oxygen transfer is one of the functions of the placenta.

Once baby is born and is using their lungs to supply the body with oxygen, this vessel usually closes on its own. This normally happens in the first 24 – 48 hours following birth of a baby at term. In babies that are born prematurely, the ductus arteriosus can take longer to close.

When this vessel does not spontaneously close, this is known as a patent ductus arteriosus. The PDA can allow blood to flow in the wrong direction, from the aorta to the pulmonary artery. The pulmonary artery takes blood to the lungs and this extra blood flow can overload the lungs. Also, the heart is having to work harder as not only is it pumping blood around the body, but it is also pumping blood through the ductus into the lungs and this puts extra strain on the heart.

How can patent ductus arteriosus be spotted?

A PDA can only be diagnosed after birth. This is because the ductus arteriosus is required during pregnancy to divert blood away from the lungs to the rest of the body.

After birth, a PDA can be suspected due to the sound of a heart murmur. To confirm a patent ductus arteriosus an echocardiogram (or echo) is usually conducted. This is an ultrasound scan of the heart – which can show the pattern of blood flow through the PDA and determine how big it is.

A baby with a PDA may have:

• Fast breathing
• Difficulty feeding
• Lethargy (sleepy or unresponsive)

How can patent ductus arteriosus be treated?

• No treatment: Sometimes the PDA can be small and not cause any symptoms. In cases like this, the cardiologists may wait until the baby grows to see if the PDA will spontaneously close

• Medical treatment: The cardiologists may decrease the baby’s fluids to see if this will encourage the PDA to close. If not, they may start a medicine that will constrict the muscle in the wall of the patent ductus arteriosus and help it close

• Surgical treatment: If the PDA is large and causing symptoms and medical treatment has not worked or is not suitable then the cardiologist may decide to that the PDA will need to be closed either through a procedure called a cardiac catheterization or surgically.

A cardiac catheterization procedure involves a small catheter being inserted into a blood vessel in the groin and being threaded up into the heart. A picture is taken of the size and shape of the PDA and then either a coil or a plug shaped device will be inserted into the PDA to block the vessel. Surgery would involve the surgeons making a small incision between the ribs on the left side and the PDA is tied and cut to stop the flow through it.

General advice for the future

Those children that have had an early diagnosis and repair of the PDA should be able to live a full and active life.

Those that have a PDA that has never been repaired or a very large PDA will need further follow up appointments. They may need repeat tests like echocardiogram. The aim of this tests is to monitor your child’s heart function so that any future heart problems are diagnosed and treated quickly.

Carys White, a radiographer from Kent, gave birth to her first child, Harriett, on 23^rd October 2013 after a healthy pregnancy. But a murmur was detected at Harriett’s 8 week check. Here is their story.

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