Assessment of myocardial function using MRI-based feature tracking in adults after atrial repair of transposition of the great arteries: Reference values and clinical utility.

BACKGROUND: Echocardiographic parameters of ventricular deformation of the systemic right ventricle (sRV) predict adverse clinical outcome in patients after atrial repair of transposition of the great arteries (TGA). We assessed myocardial deformation on cardiac MRI (CMR) and correlated these with clinical and conventional CMR parameters in TGA patients.

METHODS: Retrospective analysis of CMR studies in 91 TGA patients (66% male; mean age 30.1±5.1years) at two tertiary adult congenital heart centers was conducted. Myocardial deformation was assessed by CMR-based feature tracking (FT), providing longitudinal (LS), radial (RS), and circumferential (CS) global strain for the sRV and the subpulmonary left ventricle. A subgroup of optimal TGA was defined (NYHA class I, NT-proBNP <300pg/ml, max. exercise work load ≥100watt, no significant clinical events) as a reference cohort.

RESULTS: There was a significant correlation between FT and conventional CMR parameters. Left ventricular ejection fraction (LVEF) correlated significantly with LV LS, RS, and CS (r between 0.24 and 0.34, p values between 0.03 and 0.005). sRVEF correlated with RV CS (r=0.56, p<0.001), and RV RS (r=0.32, p=0.007). QRS duration showed a negative correlation with RV CS (r=-0.53, p<0.001), LV RS (r=-0.34, p=0.008), and LV CS (r=-0.34, p=0.006). Reference values for the novel FT method in clinically optimal TGA patients are provided.

CONCLUSION: Assessment of myocardial function using CMR-based FT is feasible in TGA patients. FT measurements related to important prognostic clinical parameters. Furthermore, we provide for the first time reference values for TGA patients in an optimal clinical status.