Patent Ductus Arteriosus (PDA) : Causes, Symptoms and Treatment

Patent ductus arteriosus (PDA) is a common congenital heart defect in which a normal fetal blood vessel fails to close after birth. Some PDAs are small and cause few issues, while others can significantly affect blood flow to the lungs and place extra strain on the heart. Early recognition and the right treatment plan help prevent long-term complications associated with congenital heart disease.

What Is Patent Ductus Arteriosus?

Patent Ductus Arteriosus (PDA) is a persistent connection between the aorta and the pulmonary artery. Before birth, babies have a natural vessel called the ductus arteriosus that allows blood to bypass the lungs. After birth, this vessel should close as part of normal heart adaptation. When it remains open, it results in patent ductus arteriosus—a structural abnormality classified under congenital heart defect, as it is present from birth and alters normal blood circulation.

What happens to blood flow in PDA?

• The aorta carries oxygen-rich blood to the body.

• The pulmonary artery carries blood to the lungs.

• In PDA, blood can flow from the aorta back into the pulmonary artery (left-to-right shunt), sending extra blood to the lungs and increasing workload on the heart.

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Patent Ductus Arteriosus Causes

People often ask about patent ductus arteriosus causes. In many cases, there is no single clear cause, but several factors increase risk:

• Prematurity: PDA is much more common in preterm infants because the closure mechanism may be immature.

• Low birth weight

• Family history of congenital heart defects

• Maternal infections during pregnancy (certain viral infections can increase CHD risk)

• Genetic or chromosomal conditions (some syndromes are associated with PDA)

• High altitude birth (lower oxygen environment can affect closure)

• Female sex (PDA is reported more often in females)
  

Even with known risk factors, PDA can occur without any identifiable trigger.

Patent Ductus Arteriosus Symptoms

Patent ductus arteriosus symptoms depend mainly on the size of the PDA and the baby’s maturity.

In small PDA

A small PDA may cause no symptoms and may be found only during a routine exam.

In moderate to large PDA (especially in infants)

Common symptoms can include:

• Fast breathing or breathing difficulty

• Poor feeding or tiring during feeds

• Poor weight gain

• Sweating (especially during feeding)

• Frequent chest infections

• Rapid heartbeat

• Signs of heart failure in severe cases (increased work of breathing, poor growth, lethargy)
  

In older children or adults (if PDA persists)

• Shortness of breath with exertion

• Easy fatigue

• Palpitations

• Reduced exercise tolerance
  

If symptoms are present, evaluation should not be delayed.

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Patent Ductus Arteriosus Murmur: What Doctors Hear

A classic clue is the patent ductus arteriosus murmur. Many PDAs are first suspected because a clinician hears a characteristic sound with a stethoscope.

• PDA often produces a continuous “machinery” murmur, usually best heard near the left upper chest.

• The murmur can vary with PDA size and pulmonary pressures.

• In premature babies, the murmur may be subtle or absent early on, so symptoms and overall clinical picture matter.

  
  

A murmur alone does not confirm PDA—testing does.

How PDA Is Diagnosed

Diagnosis usually involves:

• Echocardiography (2D Echo with Doppler): Confirms PDA, measures size, direction of shunt, and effect on heart chambers.

• Pulse oximetry: Helps assess oxygen levels.

• Chest X-ray: In larger PDAs, may show increased lung blood flow and enlarged heart.

• ECG: Sometimes shows chamber enlargement in significant shunts.

  
  

Echo is the key test because it directly visualizes the PDA and its hemodynamic impact.

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Patent Ductus Arteriosus Treatment

Patent ductus arteriosus treatment is individualized. The “best” approach depends on:

• Age (preterm infant vs term baby vs child/adult)

• PDA size and symptoms

• Effect on heart and lungs

• Presence of pulmonary hypertension

  
  

1) Observation (watchful follow-up)

If PDA is small and not causing heart enlargement or symptoms, doctors may recommend monitoring. Some small PDAs close spontaneously, especially in term infants.

2) Medical therapy (commonly in preterm infants)

In premature babies, medications that help constrict the ductus may be used under NICU supervision. Response depends on gestational age and clinical status. If medical treatment fails or is not suitable, closure is considered.

3) Patent ductus arteriosus closure (catheter-based)

For many children (and adults), patent ductus arteriosus closure is done without open-heart surgery:

• A thin tube (catheter) is guided through blood vessels to the heart.

• A coil or occluder device is placed to seal the PDA.

• Hospital stay is usually short, and recovery is quick.

  
  

This is often preferred when anatomy is suitable and the PDA is hemodynamically significant.

4) Patent ductus arteriosus surgery

Patent ductus arteriosus surgery may be recommended when:

• The PDA is not suitable for device closure (due to size or anatomy)

• The baby is very small and catheter closure is not feasible

• There are associated conditions requiring surgery

  
  

Surgery typically involves closing the PDA through a small incision, usually without needing to open the heart chambers.

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When Is Closure Recommended?

Closure decisions are based on risk vs benefit. Closure is commonly recommended if:

• The PDA is moderate/large and causes symptoms

• There is heart chamber enlargement

• There is significant extra blood flow to lungs

• There is risk of complications over time (even some small PDAs may be closed depending on clinical judgment)

  
  

In cases with advanced pulmonary hypertension, closure requires careful specialist assessment to ensure it is safe and beneficial.

What to Expect After PDA Closure

After successful patent ductus arteriosus closure, many patients have:

• Improved feeding and growth in infants

• Reduced breathing difficulty

• Better exercise tolerance in older children/adults

• Reduced risk of future complications

  
  

Follow-up usually includes repeat echocardiograms and a short period of activity guidance. The exact plan depends on the method used (device vs surgery) and the patient’s baseline condition.

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Possible Complications if PDA Is Not Treated

A significant PDA left untreated can lead to:

• Heart failure symptoms (from volume overload)

• Recurrent respiratory infections

• Pulmonary hypertension

• Rhythm issues in some cases

• Reduced growth in infants

  
  

This is why timely diagnosis and appropriate management matter.

Clinical Signs That Require Medical Evaluation

Seek medical assessment if a baby has:

• Fast breathing, chest retractions, or persistent breathing difficulty

• Poor feeding, sweating with feeds, or failure to gain weight

• Repeated chest infections

• A doctor notes a continuous murmur or abnormal heart sounds

  
  

Why Patent Ductus Arteriosus Needs Attention

If you are looking up what is patent ductus arteriosus, the key point is that PDA is an open fetal blood vessel that should close after birth. Some PDAs are harmless, but others require treatment. With modern care—medical therapy in select newborns, catheter-based patent ductus arteriosus closure, or patent ductus arteriosus surgery—outcomes are typically excellent when managed appropriately.

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Frequently Asked Questions

1. Do PDA kids get better with age?

Some children with a small PDA may improve as the duct closes naturally, especially in early infancy. However, moderate or large PDAs usually do not close on their own and may need treatment after proper evaluation.

2. At what age is PDA surgery done?

There is no fixed age for PDA surgery. Treatment can be done in infancy or early childhood, depending on the size of the PDA, symptoms, and the child’s overall heart condition.

3. Is surgery always needed for PDA?

No, surgery is not always required. Small PDAs may only need regular monitoring. Many PDAs can be treated with a catheter-based closure without open surgery. Surgery is used when other options are not suitable.

4. Is a patent ductus arteriosus serious?

A small PDA is often not serious and may cause no symptoms. Larger PDAs can become serious if left untreated, as they may affect heart and lung function over time.

5. Do we need to restrict any physical activities?

Most children with a small or treated PDA can take part in normal physical activities. Restrictions are usually needed only if the PDA is large or causing symptoms, as advised by the doctor.

6. Is this a condition that could be passed on to future children?

PDA is usually not inherited. The chance of it occurring in future children is low, although certain genetic or pregnancy-related factors can slightly increase the risk.