Incremental prognostic value of myocardial strain over ventricular volume in patients with repaired tetralogy of Fallot

The relative incremental predictive value of myocardial deformation over ventricular volume for future adverse events in patients with repaired tetralogy of Fallot (rTOF) remains unknown. We aimed to determine the incremental prognostic value of myocardial deformation over ventricular volume to predict adverse events in patients with rToF. We retrospectively included patients with rTOF who completed cardiac magnetic resonance (CMR) and follow-up in our hospital from January 2014 to October 2020, and stratified according to the presence or absence of adverse events during follow-up. The strain parameters of the right ventricular (RV) and left ventricular (LV) were obtained from CMR-derived feature tracking. Multivariable Cox proportional hazard models and net reclassification improvement analysis were used to analyze the prognostic information of biventricular strain and volume parameters in rTOF patients. Among 98 patients with rTOF, 54 (55.1%) experienced primary and/or secondary events during a median follow-up period of 27.0 months. Univariable analysis indicated that RV volume and strain were significantly associated with both primary events and all adverse events (all p < .01). Multivariable Cox regression and net reclassification improvement analyses achieved incremental global ${\chi }^2$ (all p < .001), C index (all p < .001), and overall correct reclassification by sequentially adding CMR-derived RV volume, RV strain and LV strain parameters to preexisting clinical factors in adverse events model analyses. RV and LV myocardial deformation provided incremental prognostic information and significant improvement for risk stratification over RV size and clinical variables and therefore can be combined to further enhance prognostication. RV volume and strain were significantly associated with both primary events and all adverse events, whereas LV volume and strain were associated with primary events. Ventricular myocardial deformation is a strong predictor of adverse outcomes of patients with repaired tetralogy of Fallot, providing increased prognostic information and significantly improved risk stratification over ventricular size.