Ductal Stent, Shunt, or Waiting in a 2.4-kg Neonate With Pulmonary Atresia
6-day-old boy born at 34+6 weeks, now 2.4 kg, with tetralogy of Fallot and pulmonary atresia. Branch pulmonary arteries are confluent, 3.0 and 3.2 mm; the ductus arises from the left arch and narrows to 1.8 mm. He is on PGE1 0.05 mcg/kg/min, SpO2 78–85%, lactate 1.4 mmol/L, urine output 1.8 mL/kg/h, creatinine 0.8 mg/dL. The cath lab has no neonatal covered stents and no hybrid suite; the surgeon is available; one ECMO circuit is in the hospital. Transfer would take 4 hours by ground. Parents ask why not wait until he is bigger.
1. Compare ductal stenting, a modified Blalock–Taussig shunt, and continued PGE1 with delayed surgery. Make a recommendation and state the strongest argument against it.
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Recommendation: proceed with a modified Blalock–Taussig shunt at this institution after confirming anatomy, rather than transfer for a ductal stent or indefinite PGE1.
Reasoning:
- The ductus is 1.8 mm and the cath lab lacks neonatal covered stents; a transfer adds 4 hours of PGE1 exposure, transport risk, and possible ductal closure. A stent in a 1.8-mm ductus may not provide durable flow and can distort the branch pulmonary arteries.
- A 2.4-kg, 34-week infant is small but not outside the range of experienced neonatal cardiac surgical programs; an off-pump shunt avoids CPB and can be done promptly.
- Continued PGE1 is a bridge, not a destination: apnea, edema, gastric irritation, and unpredictable ductal closure make weeks of waiting unattractive, and he will not outgrow pulmonary atresia.
Strongest argument against: a shunt in a preterm 2.4-kg infant carries real risks of shunt thrombosis, ventricular dysfunction, and prolonged ICU stay; if the unit's neonatal shunt outcomes are poor, transfer for a stent or hybrid procedure may be better. The decision should depend on institutional outcomes, not just anatomy.
2. What preoperative findings would make you cancel or change the plan?
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Findings that would change the plan:
- Pulmonary anatomy: true PA size under 2 mm, discontinuous branch PAs, or major aortopulmonary collaterals would push toward a different source of pulmonary blood flow or unifocalization strategy.
- Systemic issues: active necrotizing enterocolitis, sepsis, intracranial hemorrhage, platelets under 50,000, coagulopathy, or renal failure would delay surgery.
- Cardiac: severe ventricular dysfunction or important tricuspid regurgitation would change shunt size and postoperative planning.
- Genetic or syndromic diagnosis would affect counseling but would not by itself preclude surgery.
If the ductus were large and stentable with appropriate hardware, or if the child deteriorated on PGE1, the recommendation could shift to emergent stent or hybrid.
3. How do you counsel about ECMO and neurologic uncertainty?
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Explain that ECMO is a rescue therapy, not a planned part of the operation. If shunt thrombosis causes cardiac arrest, ECMO can buy time for thrombectomy or shunt revision, but it carries risks of bleeding, stroke, infection, and prolonged ICU stay. With one circuit, another child may need it at the same time; the team will use objective criteria and not first-come-first-served. Avoid promising a specific neurologic outcome; say that survivors of neonatal ECMO have a range of developmental outcomes and that follow-up will be arranged. Ask what matters most to them and document their goals.