Relation of Right Ventricular Dilation After Pulmonary Valve Replacement to Outcomes in Patients With Repaired Tetralogy of Fallot

The rationale for timing of pulmonary valve replacement (PVR) in patients with repaired Tetralogy of Fallot (rTOF) has focused on pre-PVR threshold values of indexed right ventricular end-diastolic volume (RVEDVi) that lead to normalization of right ventricular (RV) size after valve implantation. The goal of this study was to determine whether persistent RV dilation after PVR is associated with adverse clinical outcomes. Subjects with rTOF who underwent PVR and had a cardiac magnetic resonance (CMR) exam after valve implantation at a single center from 2001 to 2017 were included. The composite clinical outcome after PVR included: death, aborted sudden cardiac death, sustained ventricular tachycardia (VT), or NYHA class ≥3. In 189 rTOF subjects, the mean age at PVR was 23.5 ± 11.7 years, median follow-up was 6.0 years (IQR 3.4 to 8.7), and the primary outcome occurred in 14 subjects (7%). The 5- and 10-year event-free rates were 97% and 91%, respectively. Post-PVR RVEDVi was not associated with the composite outcome (p = 0.59). Independent predictors of the outcome were older age at PVR (hazard ratios [HR] 1.06; 95% confidence interval [CI] 1.02 to 1.11; p = 0.004), post-PVR lower RV ejection fraction (HR 0.91; 95% CI 0.86 to 0.97; p = 0.002), and post-PVR atrial tachyarrhythmia (HR 7.60, 95% CI 1.65 to 35.05, p = 0.009). Our study shows that post-PVR RV dilation as measured by CMR-derived RVEDVi was not associated with the composite adverse clinical outcome in this cohort. These findings challenge the validity of current guidelines for PVR, which are based on pre-procedural threshold values of RVEDVi aimed at achieving normal post-procedural RV volumes.