Right ventricular strain in repaired Tetralogy of Fallot with regards to pulmonary valve replacement

To assess right ventricular (RV) myocardial strain both globally and segmentally through feature-tracking cardiac magnetic resonance (CMR) in patients with Tetralogy of Fallot (ToF), with regards to pulmonary valve replacement (PVR).

After Ethics Committee approval, we retrospectively included 46 consecutive ToF patients who had two CMR examinations performed at our institution between March 2014 and June 2019. We divided patients into those who had not undergone PVR between the two CMR examinations (Group-0), and those who had (Group-1). Ventricular volumes were quantified on cine sequences, and strain was calculated through feature-tracking, using the previously traced segmentations. RV longitudinal and radial strain were assessed both globally and separately for the septum and free wall. Variations were normalized for intercurrent years, differences were appraised with t-tests or Mann-Whitney U.

30 patients belonged to Group-0 and 16 to Group-1. Median age was 22 years (interquartile range [IQR] 17-29 years) in Group-0, and 21 years (IQR 16-29 years) in Group-1. No significant differences were reported in RV strain between groups (p ≥ 0.254) except for RV septal radial strain, significantly higher (p = 0.010) in Group-0 (24.2 %, IQR 10.1-52.4 %) than in Group-1 (6.0 %, IQR -3.3-23.3 %) at the second CMR. Both global and segmental RV strains decreased over time in both groups, and yearly variations did not differ significantly (p ≥ 0.081) between groups.

While PVR performed at the appropriate timing eases the burden on the RV allowing for a reduction in volumes, RV strain seems to continuously deteriorate as in patients who do not undergo PVR.