Definition:Â 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). Â 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
 All Marc’s PICU cardiology FOAM can be found on PICU Doctor and can be downloaded as a handy app for free on iPhone or Android. A list of contributors can be seen here.
