Development and Validation of a Mortality Risk Score for Repaired Tetralogy of Fallot.

BACKGROUND: Robust risk assessment is crucial for the growing repaired tetralogy of Fallot population at risk of major adverse clinical outcomes; however, current tools are hindered by lack of validation. This study aims to develop and validate a risk prediction model for death in the repaired tetralogy of Fallot population. METHODS AND RESULTS: Patients with repaired tetralogy of Fallot enrolled in the INDICATOR (International Multicenter Tetralogy of Fallot Registry) cohort with clinical, arrhythmia, cardiac magnetic resonance, and outcome data were included. Patients from London, Amsterdam, and Boston sites were placed in the development cohort; patients from the Toronto site were used for external validation. Multivariable Cox regression was used to evaluate factors associated with time from cardiac magnetic resonance until the primary outcome: all-cause death. Of 1552 eligible patients (n=1221 in development, n=331 in validation; median age at cardiac magnetic resonance 23.4 [interquartile range, 15.6-35.6] years; median follow up 9.5 years), 102 (6.6%) experienced the primary outcome. The multivariable Cox model performed similarly during development (concordance index, 0.83 [95% CI, 0.78-0.88]) and external validation (concordance index, 0.80 [95% CI, 0.71-0.90]) and identified older age at cardiac magnetic resonance, obesity, type of tetralogy of Fallot repair, higher right ventricular end-systolic volume index, and lower biventricular global function index as independent predictors of death. A risk-scoring algorithm dividing patients into low-risk (score ≤4) versus high-risk (score >4) groups was validated to effectively discriminate risk of death (15-year survival of 95% versus 74%, respectively; P<0.001). CONCLUSIONS: This externally validated mortality risk prediction algorithm can help identify vulnerable patients with repaired tetralogy of Fallot who may benefit from targeted interventions.

Improved Outcomes After Pulmonary Valve Replacement in Repaired Tetralogy of Fallot.

BACKGROUND: The impact of pulmonary valve replacement (PVR) on major adverse clinical outcomes in patients with repaired tetralogy of Fallot (rTOF) is unknown. OBJECTIVES: The purpose of this study was to determine whether PVR is associated with improved survival and freedom from sustained ventricular tachycardia (VT) in rTOF. METHODS: A PVR propensity score was created to adjust for baseline differences between PVR and non-PVR patients enrolled in INDICATOR (International Multicenter TOF Registry). The primary outcome was time to the earliest occurrence of death or sustained VT. PVR and non-PVR patients were matched 1:1 on PVR propensity score (matched cohort) and in the full cohort, modeling was performed with propensity score as a covariate adjustment. RESULTS: Among 1,143 patients with rTOF (age 27 ± 14 years, 47% PVR, follow-up 8.3 ± 5.2 years), the primary outcome occurred in 82. The adjusted HR for the primary outcome for PVR vs no-PVR (matched cohort n = 524) was 0.41 (95% CI: 0.21-0.81; multivariable model P = 0.010). Full cohort analysis revealed similar results. Subgroup analysis suggested beneficial effects in patients with advanced right ventricular (RV) dilatation (interaction P = 0.046; full cohort). In patients with RV end-systolic volume index >80 mL/m2, PVR was associated with a lower primary outcome risk (HR: 0.32; 95% CI: 0.16-0.62; P < 0.001). There was no association between PVR and the primary outcome in patients with RV end-systolic volume index ≤80 mL/m2 (HR: 0.86; 95% CI: 0.38-1.92; P = 0.70). CONCLUSIONS: Compared with rTOF patients who did not receive PVR, propensity score-matched individuals receiving PVR had lower risk of a composite endpoint of death or sustained VT.