What is patent ductus arteriosus (PDA)? 

Patent Ductus Arteriosus (PDA) is a persistent opening between the two major blood vessels leading from the heart: the aorta and the pulmonary artery. In the womb, this opening called the ductus arteriosus is a normal and essential part of a baby’s circulatory system, allowing blood to bypass the lungs. Typically, this vessel closes on its own within a few days of birth. When it remains open (patent), it allows oxygen-rich blood from the aorta to mix with oxygen-poor blood in the pulmonary artery, putting extra strain on the heart and increasing pressure in the lung arteries. 

PDA is a common congenital heart condition in the UK, particularly among premature infants. While a very small PDA may cause no symptoms and might even be considered “innocent,” a large opening can lead to significant complications such as heart failure or pulmonary hypertension. Modern medical management in the UK ranges from medication to help the vessel close naturally to minimally invasive keyhole procedures that seal the opening with a specialized device. 

What We will cover in this Article 

• The transition from fetal to newborn circulation. 

• Why the ductus fails to close in some infants. 

• Recognising symptoms: From “washing machine” murmurs to breathlessness. 

• The critical link between PDA and premature birth. 

• Treatment pathways: Ibuprofen/Indomethacin vs. Device closure. 

• 2026 clinical data on long-term vascular health after PDA repair. 

The Anatomy: Fetal vs. Newborn Circulation 

Before birth, the ductus arteriosus serves a vital purpose. Because the fetus receives oxygen from the mother’s placenta rather than its own lungs, the lungs do not need a full blood supply. The ductus acts as a “short-cut,” sending blood directly into the aorta to be distributed to the rest of the body. 

Once the baby is born and takes its first breaths, the lungs expand, and oxygen levels in the blood rise. This change in oxygen concentration, along with a drop in specific hormone-like substances called prostaglandins, normally signals the muscular wall of the ductus to constrict and close. If this process fails, the result is a PDA, which forces the left side of the heart to work harder to compensate for the blood leaking back into the lungs. 

Symptoms and Clinical Detection 

The symptoms of a PDA depend entirely on the size of the opening and the gestational age of the baby. In many full-term infants, a small PDA may go unnoticed for years. However, a large PDA creates a significant “left-to-right shunt” that can be detected through several clinical signs. 

• The Murmur: A doctor listening with a stethoscope will often hear a characteristic “continuous” or “machinery” murmur, which sounds like a rhythmic washing machine. 

• Bounding Pulses: Because blood is rapidly exiting the aorta through the PDA, the pulses in the wrists and feet can feel unusually strong or “bouncy.” 

• Respiratory Distress: Babies may breathe rapidly, have a flared nose, or show “retractions” (the skin pulling in around the ribs). 

• Feeding Issues: Significant PDAs can make a baby too tired to feed effectively, leading to poor weight gain. 

The Prematurity Link 

Premature infants are at the highest risk for PDA. The more premature the baby, the more likely the ductus is to remain open. This is because the muscular wall of the ductus is less developed, and the baby’s lungs may not be efficient enough to raise oxygen levels to the point required for closure. 

Treatment: From Medicine to Keyhole Surgery 

The choice of treatment is dictated by the severity of the symptoms and the size of the infant. 

1. Watchful Waiting: Many small PDAs close on their own within the first few months of life and only require regular echocardiograms. 

2. Medication: In premature babies, medicines like Ibuprofen or Indomethacin (prostaglandin inhibitors) are often given via a drip to encourage the ductus to constrict and close. 

3. Keyhole (Catheter) Closure: This is the preferred method for older infants and children. A cardiologist guides a thin tube to the heart and places a tiny “plug” or “coil” into the PDA to seal it. 

4. Surgical Ligation: Reserved for very small babies who cannot have a catheter procedure or those where medication has failed. The surgeon places a small clip or silk tie around the vessel to close it. 

To Summarise 

Patent Ductus Arteriosus is a structural “leak” in the heart’s main plumbing that is a remnant of fetal life. While it is highly common in premature babies and can lead to heart strain, most cases are successfully managed with medication or minimally invasive closure. With the specialized neonatal and paediatric cardiac care available in the UK, the long-term outlook for children with a PDA is excellent, and most go on to have entirely normal heart function and physical capabilities. 

If your baby has a persistent fast heart rate, is struggling to breathe, or is failing to gain weight, call 999 or contact your neonatal team immediately. 

If your child with a known PDA develops a sudden, high fever and appears unusually pale or lethargic, call 999 immediately. 

Authority Snapshot (E-E-A-T Block) 

This article was reviewed by Dr. Stefan Petrov, a UK-trained physician (MBBS) with postgraduate certifications in ACLS and BLS. Dr. Petrov has extensive clinical experience in general medicine and emergency care, having worked in hospital wards and intensive care units where the management of neonatal hemodynamics and cardiac monitoring is a daily priority. His expertise ensures this information on PDA is accurate, safe, and aligned with current NHS and British Congenital Cardiac Association (BCCA) standards.