Improved long-term outcomes in double-inlet left ventricle and tricuspid atresia with transposed great arteries: systemic outflow tract obstruction present at birth defines long-term outcome

OBJECTIVES: In 2 subtypes of functional single ventricle, double inlet left ventricle (DILV) and tricuspid atresia with transposed great arteries (TA-TGA), systemic output passes through an outflow chamber before entering the aorta. Intracardiac obstruction to this pathway causing systemic outflow tract obstruction (SOTO) may be present at birth or develop over time. Long-term survival after Fontan has not been defined. We defined outcomes utilizing records from 2 centres that were cross-checked with data from a bi-national Fontan Registry for completeness and accuracy. METHODS: Two hundred and eleven patients were identified, 59 TA-TGA,152 DILV. Median follow-up was 17 years (range 4 days to 49.8 years). The Kaplan-Meier method was used for all of the time to event analyses and the log-rank test was used to compare the time-to-events. Cox proportional hazard models were used to test the association between potential predictors and time-to-event end-points. RESULTS: TA-TGA had reduced survival compared to DILV (cumulative risk of death 28.8% vs 11%, hazard ratio (HR) 3.1 (95% confidence interval (CI) 1.6-6.1), P = 0.001). In both groups, SOTO at birth carried a worse prognosis HR 3.54 (1.36-9.2, P = 0.01). SOTO was not more common in either morphology at birth ( P = 0.20). Periprocedural mortality accounted for 40% of deaths. Fontan was achieved in 82%, DILV were more likely to achieve Fontan than TA-TGA (91% vs 60%, P <0.001). After Fontan there were 9 deaths (4%) with no difference according to morphology. CONCLUSIONS: Patients with TA-TGA have poorer outcomes than those with DILV, affecting survival and likelihood of achieving Fontan. SOTO at birth carries a high risk of mortality suggesting that, when present, initial surgical management should address this.