Optimal Timing of Pulmonary Valve Replacement for Repaired Tetralogy of Fallot: Implications for Left Ventricular Function and Postoperative Outcomes

F. Shikata¹, T. Kitamura¹, M. Fukuzumi², T. Mishima¹, Y. Motoji³, D. Ishiwaki¹, S. Kaneda¹, K. Miyaji^4
1Kitasato University School of Medicine, Sagamihara, Kanagawa ²Ageo Central General Hospital, Ageo, Kanagawa ³Kitasato university shool of medicine, Sagamihara, Kanagawa ⁴Dept. of Cardivascular Surgery, Kitasato University School of Med, Sagamihara, Kanagawa

Purpose: The indication for PVR in patients with repaired TOF has been based solely on RV function, neglecting the impact on LV function. We have observed cases where LV function had already deteriorated due to prolonged observation for PVR indication. The aim is to investigate the optimal timing of PVR.

Methods: We retrospectively included forty patients who underwent bioprosthetic PVRs after TOF repair at a single institution from 2008. The median age at PVR was 21 years (interquartile range (IQR), 16-39), and the median interval after TOF repair was 18.1 years (IQR, 14.5-34.7). Cardiac MRI (CMRI) was performed before PVR, one year post-PVR, and five years post-PVR to assess biventricular function. Multiple regression analysis was conducted to identify variables predicting postoperative LV function.

Results: There were no early deaths, but one late death occurred. LV ejection fraction (EF) improved from 52±10% to 56±9% one year after PVR (P=0.002) with a significant reduction in LV end-systolic volume index (LVESVI) from 46 mL/m2 (IQR, 37-58) to 39 mL/m2 (IQR, 33-53), RV end-diastolic volume index (RVEDVI) from 147 mL/m2 (IQR, 119-178) to 93 mL/m2 (IQR, 83-109), and RV end-systolic volume index (RVESVI) from 72 mL/m2 (IQR, 54-102) to 48 mL/m2 (IQR, 38-59) (P < 0.001). Multiple regression analysis revealed that the interval (years) after TOF repair predicted postoperative 1-year LVEF (R, -0.43; P=0.002). ROC analysis demonstrated that the interval after TOF repair significantly predicted 1-year postoperative LV dysfunction (EF < 55%) with an AUC of 0.80 and a cutoff level of 18.5 years (sensitivity 0.83; specificity 0.76). Furthermore, there was no improvement in left ventricular function during the 5-year follow-up on CMRI in the group undergoing PVR ≥18.5 years after TOF repair (52.7±8.8% to 49.3±10.0%, P=0.3). The lower freedom rate of postoperative new-onset arrhythmias was significantly observed in the group with PVR ≥18.5 years after TOF repair compared to those with < 18.5 years (58% versus 86%, P=0.003).

Conclusion: Performing pulmonary valve replacement (PVR) before the interval after TOF repair reaches 18.5 years offers significant benefits, preserving postoperative left ventricular (LV) function and reducing the incidence of postoperative new-onset arrhythmias. Avoiding PVR in younger patients ( < 17 years old) can prevent rapid bioprosthetic deterioration and early reoperation.

Identify the source of the funding for this research project: none