Right ventricular dilatation in patients with pulmonary regurgitation after repair of tetralogy of Fallot: How fast does it progress?

Objective: Pulmonary valve regurgitation (PR) and right ventricular (RV) dilatation are important residual findings after surgical repair of tetralogy of Fallot (TOF). We sought to describe the natural course of RV dilatation over time in patients with severe PR after TOF repair and to determine risk factors for quick progression of RV dilatation and dysfunction. Methods: Data of 85 consecutive TOF patients with PR and RV dilatation, undergoing serial cardiovascular magnetic resonance (CMR) scans between July 2002 and December 2016 in two institutions, were retrospectively reviewed. The dataset was analyzed regarding right and left ventricular (LV) volume and function and potential risk factors of progressive RV dilatation. Results: There was no significant increase in RV end-diastolic volumes (RVEDV$_{i}$) indexed body surface area (BSA) (median 150 [81-249] vs. 150 [82-260] mL/m$^{2}$) and end-systolic volumes indexed for BSA (RVESV$_{i}$) (75 [20-186] vs. 76 [39-189] mL/m$^{2}$) between the first and last CMR in the overall group. Similarly, there were no significant changes in LV volumes indexed for BSA (LVEDV$_{i}$ 78 [56-137] vs. 81 [57-128] mL/m$^{2}$ and LV end-systolic volume index 34 [23-68] vs. 35 [18-61] mL/m2). Global function remained also unchanged for both ventricles. RVEDVi increased statistically significantly (≥20 mL/m2) in twenty patients (24%) from 154 mL/m$^{2}$ (87-237) to 184 mL/m$^{2}$ (128-260, P < 0.001). LV dimensions showed a similar trend with LVEDVi increase from 80 ml/m$^{2}$ (57-98) to 85 ml/m$^{2}$ (72-105, P = 0.002). Shorter time interval between repair and first CMR was the only risk factor predictive for progressive RV dilatation. Conclusion: In the majority of patients with repaired TOF and severe PR, RV dilatation is unchanged during a follow-up of 3 years. RV dilatation seems to progress early after surgery and subsequently stabilize. RV dilatation significantly progresses in a subgroup of 24% of patients, with a shorter time interval since surgical repair