Synopsis
Explain why the arterial duct persists in different age groups, recognise haemodynamically important pulmonary overcirculation, and choose observation, neonatal pharmacological closure, catheter treatment or surgery safely.
- The arterial duct connects the pulmonary artery to the descending aorta in fetal life. Oxygen exposure and falling prostaglandins normally trigger functional then anatomical closure after birth.
- Prematurity strongly favours persistence because ductal smooth muscle is immature and illness, hypoxaemia and circulating prostaglandins oppose constriction.
- After pulmonary resistance falls, a PDA usually carries left-to-right flow, creating pulmonary overcirculation, left-heart volume loading and diastolic runoff from systemic circulation.
- Classic findings in a term infant or child are a continuous left infraclavicular machinery murmur, bounding pulses and wide pulse pressure; very preterm infants often have less typical signs.
- Initial assessment combines respiratory and feeding burden, pulse and perfusion pattern, blood pressure and serial targeted neonatal or paediatric echocardiography.
- Echocardiography confirms ductal anatomy, direction and velocity of flow, left-heart loading and systemic-flow effects and excludes a lesion that depends on ductal patency.
- An asymptomatic tiny duct may be observed or discussed for elective closure; a persistent haemodynamically important duct needs specialist assessment for treatment.
- For a haemodynamically significant PDA in an eligible preterm infant, a licensed ibuprofen course is 10 mg/kg IV, then 5 mg/kg at 24 and 48 hours, with renal, bleeding, gut and infection safety checks before every dose.
- A suitable persistent PDA in an older infant or child is usually closed by a transcatheter device; surgery is used when size, weight, anatomy or failed pharmacological or catheter treatment makes that preferable.
- Do not treat a PDA number in isolation: evidence for active closure in extremely preterm infants is context-dependent, so gestation, respiratory course, systemic effects and local neonatal policy determine timing.
Key red flags
Increasing ventilatory requirement, pulmonary haemorrhage, hypotension or poor systemic perfusion in a very preterm infant warrants urgent haemodynamic reassessment for a significant duct and other causes.
Tachypnoea, feeding diaphoresis, hepatomegaly, bounding pulses and faltering growth indicate substantial pulmonary overcirculation in an infant beyond the immediate newborn period.
A continuous murmur may be absent in a ventilated preterm baby or when pulmonary and systemic pressures are similar; haemodynamic significance cannot be graded by sound alone.
Central cyanosis or differential lower-limb cyanosis suggests pulmonary hypertension with right-to-left ductal flow or additional congenital anatomy and needs urgent specialist assessment.
Oliguria, rising creatinine, thrombocytopenia, active bleeding, suspected necrotising enterocolitis or severe infection materially changes the safety of cyclo-oxygenase inhibitor treatment.
A duct that is maintaining pulmonary or systemic flow in another congenital lesion must not be closed; confirm complete anatomy before intervention.
Investigation priorities
Establish clinical burden across respiratory support, perfusion, feeding and growth.
Management branches
A preterm infant has a persistent duct and respiratory or systemic concerns.
- Integrate gestation, ventilation, oxygen, perfusion, feeds and serial echocardiographic flow effects.
- Treat alternative causes of deterioration and optimise ventilation, nutrition and fluid balance without provoking dehydration.
- Discuss conservative, pharmacological or procedural closure within the neonatal and cardiac multidisciplinary pathway.