Outcomes of Delayed Norwood Operation in High-Risk Patients-Time to Reconsider the Dogma of a Primary Norwood Operation?

Bilateral pulmonary artery banding was performed very early in life as a bridge to the delayed Norwood operation in high-risk patients.

• bPAB was performed at a median age of 2.5 days (IQR: 2-4)
• 20 consecutive patients were included from a single centre between 2019 and 2024
• All patients had hypoplastic left heart syndrome or variants with multiple risk factors
• The study design was single-centre and retrospective

The study population carried a high burden of preoperative risk factors.

• Prematurity was present in 35% of patients
• Low birth weight (<2.5 kg) was present in 25% of patients
• Non-cardiac comorbidities were present in 25% of patients
• Genetic syndromes were present in 50% of patients
• Preoperative cardiogenic shock was present in 35% of patients
• Restrictive atrial septum was present in 25% of patients

The operative survival rate following the delayed Norwood operation was 75% in this high-risk cohort.

• The median age at delayed Norwood operation was 36 days (IQR: 29-79)
• Operative survival was 75% across all 20 patients
• The authors noted these outcomes were comparable to those of lower-risk patients undergoing primary Norwood operation
• The delayed Norwood was performed a median of approximately 33 days after initial bPAB

Patients who underwent the delayed Norwood within 4 weeks of bPAB did not require any pulmonary artery reinterventions.

• PA reintervention rate was 0% in patients whose DN was performed within 4 weeks of bPAB
• The authors suggest a DN procedure around 4-6 weeks following bPAB may reduce surgical or catheter-based reinterventions
• PA reinterventions were a notable concern with longer intervals between bPAB and delayed Norwood

Postoperative hemodynamic recovery was demonstrated by rapid lactate clearance and significant reduction in vasoactive inotropic support.

• Median lactate clearance time was 8 hours (IQR: 5-18) postoperatively
• The median vasoactive inotropic score decreased by 47% within 48 hours postoperatively
• These metrics were used as indicators of postoperative hemodynamic stability

Cerebral near-infrared spectroscopy values improved progressively in the early postoperative period in patients who did not require ECMO support.

• In patients without postoperative ECMO, cerebral NIRS values improved from 53% at 0 hours to 58% at 12 hours and 63% at 36 hours postoperatively
• Patients requiring postoperative ECMO did not demonstrate the same improvement pattern
• NIRS was used as a surrogate measure of cerebral oxygenation and perfusion

The authors propose that a delayed Norwood performed approximately 4-6 weeks after bPAB may optimize outcomes in high-risk patients.

• The proposed timing window of 4-6 weeks is intended to allow neonatal hemodynamic stabilization and organ maturation while minimizing risk of PA distortion requiring reintervention
• The authors frame this as a reconsideration of the 'dogma of a primary Norwood operation'
• The approach is positioned as an alternative for patients with preoperative cardiogenic shock, prematurity, low birth weight, non-cardiac comorbidities, genetic syndromes, and restrictive atrial septum