11/14/24, 10\:50 AM Patent Ductus Arteriosus (PDA)

Patent Ductus Arteriosus (PDA)

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Patent ductus arteriosus (PDA)\: failure of the ductus arteriosus to close within the
More common in premature infants but also occurs in term infants.
Accounts for up to 10% of all congenital heart defects.
Pathophysiology\: ductus arteriosus remains open, leading to left-to-right shunt from aorta to pulmonary artery, causing
pulmonary over-circulation and heart failure.
Risk factors\: prematurity, low birth weight, other congenital heart defects, di
sepsis).
Symptoms\: poor feeding, failure to thrive, respiratory distress (tachypnoea, dyspnoea), increased ventilator requirements in
premature infants, potential for necrotising enterocolitis.
Examination
dynamic precordium.
Investigations\:
ECG\: normal in small PDA, left ventricular hypertrophy in large PDA.
Echocardiogram\: shows PDA, assesses size,
Chest X-ray\: normal in small PDA, signs of volume overload in large PDA.
Management\:
Medical\:
haemodynamically compromised infants.
Surgical\: closure for severe cases, typically in larger and older infants.
Complications\: respiratory failure, cardiac failure, pulmonary vascular disease, necrotising enterocolitis, failure to thrive;
signi
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Introduction

1
A patent ductus arteriosus is the failure of the ductus arteriosus to close within the
common in premature infants but also occurs in term infants.
Patent ductus arteriosus accounts for up to 10% of all congenital heart defects.

Aetiology

The ductus arteriosus is a key part of fetal circulation, connecting the pulmonary arteries with the aorta to bypass the
lungs in utero.
After delivery, the rapid decrease in pulmonary vascular resistance diverts blood through the pulmonary circulation, while
the increase in PaO2 and decline in prostaglandin causes the ductus arteriosus to close.
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In some situations, this does not happen, leading to a patent ductus arteriosus (Figure 1). A large PDA can lead to the
development of a left-to-right shunt where blood moves from the systemic circulation to the pulmonary circulation.
Figure 1. Patent ductus arteriosus

Risk factors

Risk factors for a patent ductus arteriosus include\:
Prematurity
Low birth weight
Other congenital heart defects
Di

Clinical features

History

The clinical presentation of a patent ductus arteriosus depends upon the duct's size and the patient's gestational age.
With a large PDA, there may be a history suggestive of heart failure (due to left-to-right shunting of blood), including\:
Poor feeding
Failure to thrive
Respiratory distress with tachypnoea and dyspnoea. In premature infants, this may present with an increase in ventilator
requirements.
Premature infants can also develop necrotising enterocolitis associated with a patent ductus arteriosus.
These symptoms are likely to occur earlier and be more severe in a premature infant than in a term infant.

Clinical examination

Clinical examination
have no clinical signs.
Typical clinical cardiovascular examination may include\:
Wide pulse pressure
Bounding pulses with a dynamic precordium
Grade 1-3 continuous machinery murmur heard loudest at the left upper sternal edge

Di

Possible dicongenital heart defects which may be
associated with PDA or arise independently.

Investigations

Bedside investigations

Relevant bedside investigations include\:
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ECG\: may be normal with a small PDA; left ventricular hypertrophy can occur with large PDAs

Imaging investigations

Relevant imaging investigations include\:
Echocardiogram\: will demonstrate the PDA and assess other parameters, including size,
abnormalities
Chest X-ray\: with a small PDA, this may be normal. With a large PDA, there may be evidence of volume overload and
prominence of the left atrium and ventricle

Management

Management depends on the size of the PDA and its impact on the infant.

Medical management

Some infants will outgrow the PDA. Fluid restriction and diuretics are used to manage the symptoms while this happens.
Ibuprofen, indomethacin, and paracetamol have all been used to reduce prostaglandins and close a patent ductus
arteriosus. This is used when the infant is haemodynamically compromised by the PDA.

Surgical management

Surgical closure of a patent ductus arteriosus may be considered in severe cases and is typically considered in larger and
older infants.

Complications

If a PDA is large and not managed appropriately, complications include\:
2
Respiratory failure
Cardiac failure
Pulmonary vascular disease
Necrotising enterocolitis
Failure to thrive
Haemodynamically signi
complications.

References

Clyman R. I b u p r o f e n a n d P a t e n t D u c t u s A r t e r i o s u s . September 2000. Available from\: [LINK]
Dice and Bhatia. P a t e n t D u c t u s A r t e r i o s u s \: A n O v e r v i e w . Jul-Sep 2007. Available from\: [LINK]

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Contents

Introduction
Aetiology
Risk factors
Clinical features
Di
Investigations
Management
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