Multi-Center Comparison of Hybrid and Norwood Procedure in Patients with Fontan Circulation

OBJECTIVE: The hybrid stage 1 procedure (HS1P) has been proposed as an alternative to the Norwood operation. We utilized a multicenter database to compare both strategies. METHODS: The Fontan Outcomes Registry using Clinical Examinations was queried for patients who underwent HS1P or Norwood. Propensity score matching was performed. Composite outcome (death, transplant listing, protein losing enteropathy, plastic bronchitis, atrial/ventricular tachyarrhythmia, or pulmonary artery (PA) reintervention) and cardiac magnetic resonance (CMR) variables were compared. Secondary analyses compared between HS1P and shunt type (Sano versus Blalock-Thomas-Taussig (BTTS)). RESULTS: 228 patients were analyzed (76 HS1P, 152 Norwood) after exclusion and matching. Median follow-up after Fontan was 14 years (95% CI: 13.0-15.1) using the reverse Kaplan-Meier method. The freedom from composite outcome was 82.3/74.5/61.2% for HS1P patients compared to 81.4/69.5/54.7% for Norwood patients at 5/10/15-year follow-ups, respectively (HR=1.02, 95% CI: 0.62-1.70, p=0.9305). Individual components of the composite outcome were also similar between HS1P and Norwood in the matched cohort including PA reintervention. CMR and echocardiographic parameters did not differ between groups. In a three group analysis of the unmatched cohort (n=954) using BTTS as the reference, HS1P was not associated with differences in adjusted hazard for the composite outcome or its individual components compared with BTTS. CONCLUSIONS: HS1P in those who survived to Fontan completion had comparable Fontan era outcomes and CMR findings to Norwood in a propensity matched multicenter cohort. Further longitudinal work is essential to refine patient selection and to optimize long-term outcomes.