In complete transposition of the great arteries (TGA) palliated by atrial switch operation, systemic right ventricle (sRV) failure and rhythm disturbances compromise survival. We aimed to determine predictive factors of severe cardiovascular events in this population.

Forty-eight adult patients with TGA palliated (36 males, median age=32 years, IQR [23–35]) were prospectively enrolled from 2011 to 2012. At baseline, all subjects underwent a clinical examination with ECG and exercise test, an echocardiography, a cardiac magnetic resonance imaging (cMRI) assessment and biomarkers measurements. Main adverse cardiac events (MACE) were defined by hospitalization for heart failure, arrhythmia, heart transplantation and death.

At baseline, most of patients were asymptomatic (85% NYHA1, median predictive VO2=66% IQR [58–73]), with a relatively good sRV function (cMRI sRVEF=52% IQR [44-58]), and tricuspid regurgitation grade was mild in 87%. Baseline concentration of BNP was 34pg/ml (IQR [14-54]) but higher than in controls (P<0.01), as well as myocardial collagen biomarkers concentrations (pro-MMP1 and P3NP, P<0.05). After a mean follow-up period of 7±0.3 years, 9 MACE occurred (2.7% patient-years) 4 patients experienced HF, 4 atrial arrhythmia and 1 ventricular tachycardia. 2 patients were transplanted and none death was observed. Among baseline characteristics, NYHA functional class ≥2 (HR=5.17 95%CI [1.37–19.59], P=0.04), end-diastolic and end–systolic sRV volumes (P≤0.02) and BNP (HR=1.02 95%CI [1.00–1.03], P=0.01), were significantly predictive of MACE. Cumulative incidence of MACE in patients with NYHA functional class ≥2 or BNP≥150pg/mL was 43% to 2 years compared to 5% in patients without (Fig. 1).

Patients with a TGA palliated by atrial switch are at high risk of severe cardiovascular events. Increase in NYHA functional class and BNP concentration must be regularly controlled to detect patients at risk.