Long-Term Outcomes of Systemic-to-Pulmonary Artery Shunt in Patients with Functional Single Ventricle and Heterotaxy Syndrome

Objectives: We sought to determine the long-term outcomes and mortality-associated factors after systemic-to -pulmonary artery shunt (SPS) in patients with heterotaxy syndrome. Methods: We retrospectively analyzed all patients with a functional single ventricle and heterotaxy syndrome who underwent SPS at our center from Jan-uary 2001 to April 2022. Results: This study involved 84 patients. Restrictive pulmonary blood flow requiring early modulation was presented in 34 (40%) patients. Compared with patients without restrictive pulmonary blood flow (N = 50 [60%]), the postnatal survival of these 34 patients was significantly lower at 10 years (log rank: p = 0.04), but the statistical significance disappeared at 20 years (log rank: p = 0.18). Among 31 patients who underwent SPS, 11 (35%) had extracardiac total anomalous pulmonary venous connection (TAPVC). The survi-val rate after SPS was 80% at 10 years. Cox regression analysis showed that extracardiac TAPVC (hazard ratio 6.44, 95% confidence interval 1.23-33.7, p = 0.03) and pulmonary venous obstruction (PVO) at TAPVC repair (hazard ratio 11.2, 95% confidence interval 2.13-58.5, p = 0.004) were significantly associated with death. In 25 patients who underwent bidirectional cavopulmonary shunt (BCPS), surgical interventions on the pulmonary artery (PA) were performed after SPS in 7 of 9 patients with PA coarctation, 3 of 4 with non-confluent PAs, and 4 of 12 with normal PAs. At SPS, primary central PA plasty was performed in three patients with PA coarctation and 2 with non-confluent PAs. There was no significant difference in the PA index before BCPS between patients with and without primary central PA plasty (p = 0.49). Among 20 patients who underwent total cavopulmonary connection (TCPC), adverse events occurred in 7 (35%) patients, including death in 1 (5%), intervention for pul-monary arteriovenous malformation (PAVM) in 3 (15%), and surgical intervention for PVO in 3 (15%). The B-type natriuretic peptide concentration was significantly higher in patients with than without adverse events (p = 0.02). The adverse event-free survival rate after TCPC was 69% at 10 years. Conclusion: Extracardiac TAPVC and PVO at TAPVC repair were significantly associated with death after SPS in patients who had het-erotaxy syndrome with a single ventricle. Surgical interventions on the PA were frequently required after SPS in patients with PA coarctation or non-confluent PAs. Although satisfactory survival was achievable after TCPC, late-onset PAVM and PVO remain concerns.