Time course of right ventricular functional parameters after surgical correction of tetralogy of Fallot determined by cardiac magnetic resonance

Abstract

To evaluate changes of right ventricular (RV) parameters in follow-up examinations after corrected tetralogy of Fallot (TOF) by cardiac magnetic resonance (CMR). CMR was performed twice within 4 years in 45 patients using a 1.5 T scanner. RV-volumes and pulmonary-regurgitant-fractions (PRF) were calculated from standard cine-sequences and flow-sensitive gradient-echo images, respectively. Patients were divided into two groups depending on the post-operative (po) interval (group 1 ≤5 years po; group 2 >5 years po) and subgroups depending on type of surgery (transannular vs. non-transannular). Patient groups were compared among each other and differences between 1st and 2nd CMR were assessed. Furthermore, patients were compared with 25 healthy volunteers. Compared with controls RV-size was increased (group 1: p = 0.007; group 2: p < 0.001) and RV function decreased (group 1: p = 0.02; group 2: p < 0.001) in po TOF-patients. PRF was higher in group 2 compared with group 1 (p = 0.04) and significant changes of PRF between 1st and 2nd CMR were found in group 2 (p < 0.01), but not in group 1 (p = 0.29). Compared with the non-transannular subgroup, PRF (p < 0.001) and RV end-diastolic-volume index (RV-EDVI) (p = 0.03) were significantly higher in patients with a transannular patch, EDVI increased between 1st and 2nd CMR. After correction, no significant changes of RV myocardial mass index (RV-MMI) were found. After correction of TOF, RV-size, RV-muscle mass (RV-MM) was increased and ejection fraction decreased in "early" follow-up already. Whereas these parameters can remain stable over a long time period, the PRF significantly increased in "late" follow-up dependent on the po interval. Overall, transannular patching went along with higher PRF and bigger RV-size as well as a greater dynamic of these parameters in the time course, which makes this subgroup highly in need of regular follow-up examinations for the optimal timing of re-interventions. In contrast, the increased RV-MM demonstrated no regression po.