Patent ductus arteriosus

Question 1

PDA - background

Answer 1

1. Definition = failure of ductus arteriosus to close normally after birth
2. Ductus arteriosus connects the pulmonary artery to the descending aorta
3. Typically closes within 1-3d of birth in term infants
4. PDA can be due to congenital abnormality or severe prematurity. Common in preterms (>50% if VLBW)
5. Clinical findings depend on size of duct and amount of blood flow across vessel

Question 2

PDA - presentation

Answer 2

Small
1. Usually asymptomatic

Large

2. Systolic or continuous machinery murmur at upper left sternal edge radiating to heart failure
3. Poor growth, feeding difficulty
4. Respiratory difficulty, recurrent chest infections
5. Heart failure. Apex may be displaced and forceful

Question 3

PDA - ix

Answer 3

1. ECG
2. CXR - presence of cardiomegaly and pulmonary plethora idnicates large shunt
3. **Echo - confirms dx

Question 4

PDA - mx

Answer 4

If asymptomatic:
1. Observe bc most close spontaneously

If symptomatic (in a preterm infant), consider the following:

2. Restrict fluids, e.g. 100-120mL/kg/d. Optimise blood oxygenation - e.g. blood transfusion if anaemic
3. Treat heart failure, e.g. frusemide 1mg/kg BD PO or IV
4. Consider pharmacological closure (e.g. indomethacin or ibuprofen - these are NSAIDs which inhibit prostaglandin synthesis)
5. Surgery may be necessary if medical management fails to control symptoms or if there is significant heart failure, ventilator dependence or prolonged failure to close

Question 5

PDA - prognosis

Answer 5

1. Generally good
2. But infants who require PDA tx often have other morbidities that affect prognosis, including severe BPD
3. Surgery after failed medical tx carries a significant risk of mortality
4. PDA much less likely to close when present in term infants
5. Medical tx in term infants is not likely to be effective