P234 - MEDIUM- AND LONG-TERM OUTCOMES OF SURGICAL MANAGEMENT IN PEDIATRIC CONGENITALLY CORRECTED TRANSPOSITION OF THE GREAT ARTERIES: A CANADIAN MULTI-CENTER COHORT STUDY

Background: Congenitally corrected transposition of the great arteries (ccTGA) is defined by atrioventricular and ventriculo-arterial discordance and often associated with other structural and conduction abnormalities. While multiple surgical strategies exist—physiologic repair, anatomic repair, and Fontan palliation—population-based pediatric outcome data remains scarce. This study evaluates survival, intervention rates, ventricular function and atrioventricular valve regurgitation (AVVR) following these surgical approaches across Canada.

METHODS AND RESULTS: This multi-center, retrospective cohort study included children < 18 years with biventricular ccTGA at one of 14 participating pediatric cardiology centers between 2005-2020. We excluded patients with a univentricular heart. Patients were assigned to one of 4 groups: physiologic repair, anatomic repair, Fontan palliation, or no definitive repair (NDR), defined as a procedure to increase or decrease pulmonary blood flow, a pacemaker, or no surgery.

A total of 263 children (60% male) met inclusion criteria. Of these, 45% (119/263) had NDR, 33% (88/263) physiologic repair, 17% (46/263) anatomic repair, and 4% (10/263) Fontan palliation. Overall survival was 91% with no significant difference between groups, at a median follow-up of 14.4 years (IQR 6.7-18.0). The cumulative number of surgical procedures was highest in the anatomic repair group (mean 3.2 operations by 15 years of age, 95% CI 2.7, 3.9) relative to the physiologic repair (2.5, 95% CI 2.1, 2.9) and NDR group (1.3, 95% CI 1.0, 1.7) (Figure). Relative to patients with a physiologic repair, the hazard of developing moderate-severe RV dysfunction on 2+ consecutive echocardiograms was lower among patients with an anatomic repair (HR 0.32, 95% CI 0.04-2.91) or NDR (HR 0.08, 95% CI 0.01, 0.83) (p=0.03). However, freedom from moderate-severe systemic ventricular dysfunction (LV or RV) was similar between groups: compared to physiologic repair, the HR was 1.06 (95% CI 0.24, 4.70) for anatomic repair and 0.09 (95% CI 0.01, 0.96) for NDR. The hazard of developing moderate-severe systemic AVVR was lower in patients with an anatomic repair relative to those with a physiologic repair (HR 0.33, 95% CI 0.16, 0.68, p=0.01).

Conclusion: Survival in children with CCTGA is high despite the complexity of this lesion. Anatomic repair is associated with more cumulative surgical procedures in childhood relative to physiologic repair. The risk of systemic ventricular dysfunction is not significantly different between anatomic and physiologic groups. However, anatomic repair is associated with a lower risk of moderate-severe systemic AVVR over time. Population-based adult outcome data is required to understand the impact of management decisions in childhood.