Patent ductus arteriosus

Definition: postnatal communication between MPA and descending aorta. Incidence 0.3-4:10.000

Physiology:

Functional closure of DA is usually within 10-15 hrs of birth (triggered by a rise in paO2 and decrease in PGE2 and PGI2).  However VLBW and especially ELBW infants have a symptomic persistent PDA (reduced sensitivity to all the above). The PDA leads to increased PBF and increased LV volume load.

Diagnosis:

Echo (PDA >1.4mm/kg, LA or LV enlargement; diastolic flow reversal in the descending aorta indicates haemodynamic significance); BNP >1000pg/ml.

Problems in PDA:

• Neonates: prolonged ventilation → BPD/CLD, IVH, PVL, NEC.
• Children/Adolescents: LVH (→ CCF), Eisenmenger syndrome, growth restriction, aneurysmal dilation of PDA, calcification, infective endocarditis.

Preoperative preparation:

ECG, CXR, CUS, FBE, clotting, UEC, PRBC (2), FFP (2), platelets (1), cryoprecipitate (2).

Methylprednisolone 10mg/kg 12hrs and 6hrs pre surgery in neonates.

Surgery:

Transcatheter PDA closure or surgical ligation by left posterolateral thoracotomy or VAT.

Postoperative management:

Usually unproblematic postoperative course, nil support required, early extubation if feasible.

Outcome:

Low mortality and morbidity (potentially adverse events include: laryngeal nerve damage, chylothorax, pneumothorax, bleeding).

References:

[1] Critical Heart Disease in Infants and Children; 2nd ed, Nichols et al: Aortopulmonary Septal Defects and Patent Ductus Arteriosus

[2] Ann Surg. 46:33; 1907: Munro: Surgery of the vascular system, I. Ligation of the ductus arteriosus

[3] Ann Pediatric Card. 2009;2: 36-40:Azhar et al: Transcatheter closure of patent ductus arteriosus: evaluating the effect of the learning curve on outcome

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