Short- and Mid-term Cardiac Ventricular Remodelling After Pulmonary Valve Replacement in Adults With Repaired Tetralogy of Fallot.

OBJECTIVES

Pulmonary valve replacement (PVR) in patients with repaired tetralogy of Fallot (rTOF) is performed to preserve right ventricular (RV) function and improve exercise capacity. The effects of PVR extend beyond the RV, influencing left ventricular (LV) performance through biventricular interdependence. This study aimed to evaluate the rate of structural and functional ventricular adaptation after PVR, with a focus on risk stratification and clinical management.

METHODS

We prospectively enrolled 74 patients with rTOF who underwent surgical PVR at Bambino Gesù Paediatric Hospital. The mean age at initial repair was 0.8 years and at PVR 17.2 years; mean body surface area 1.74 m2. Cardiovascular magnetic resonance (CMR) and cardiopulmonary exercise testing (CPET) were performed preoperatively, 6 months after surgery, and at midterm follow-up (median 57 months). Morphological and functional changes were assessed with ANOVA, and correlations between ventricular parameters were analysed. Receiver-operating-characteristic (ROC) curves identified thresholds for RV normalization.

RESULTS

Indexed RV end-diastolic volume (RVEDVi) decreased from 166.8 ± 30.1 mL/m2 (95% confidence interval [CI] 162.5-171.1) to 121.1 ± 22.4 mL/m2 (95% CI 117.0-125.2) postoperatively and 130.2 ± 23.5 mL/m2 (95% CI 126.1-134.3) at follow-up. Indexed RV end-systolic volume (RVESVi) decreased from 85.7 ± 21.5 mL/m2 (95% CI 81.2-90.2) to 56.1 ± 14.9 mL/m2 (95% CI 52.6-59.6) and 61.9 ± 16.3 mL/m2 (95% CI 58.1-65.7). RV ejection fraction improved from 49.2% (95% CI 47.3-51.1) to 55.6% (95% CI 53.6-57.6). ROC analysis identified pre-operative cut-offs RVEDVi ≤ 157.5 mL/m2 and RVESVi ≤ 68.5 mL/m2 for RV normalization (AUC 0.871 [95% CI 0.76-0.98]; 0.822 [95% CI 0.71-0.92]). Strong pre-operative correlations between RV and LV volumes (r = 0.79, P < .001) persisted post-operatively, with a new correlation between right ventricular ejection fraction [RVEF] and left ventricular ejection fraction [LVEF] (r = 0.65, P < .001).

CONCLUSIONS

PVR leads to immediate and sustained RV reverse remodelling, with improved systolic function and reinforced biventricular coupling. Early intervention-before RVESVi exceeds 68.5 mL/m2-offers the best chance for RV normalization. Integrating CMR with CPET provides a multiparametric strategy to optimize timing, patient selection, and long-term follow-up in rTOF.