Discussion

Our results demonstrate that pulmonary valve reconstruction using autologous right atrial tissue significantly reduces right ventricular dysfunction over a 1-year follow-up while accelerating postoperative recovery (Figure 2, Table 3). The odds ratio indicates that patients with standard repair are 2.39 times more likely to develop right ventricular insufficiency, with a moderate-to-large effect size (Cohen’s d for pulmonary regurgitation jet width: 1.71–2.10). These results challenge the conventional paradigm that accepts pulmonary regurgitation as an inevitable trade-off for relieving right ventricular outflow tract obstruction. ^{Reference Tweddell12} The right atrial wall, with its unique elastin and type III collagen-rich matrix, might explain why it works better than synthetic alternatives. ^{Reference Deutsch13} Unlike polytetrafluoroethylene, which induces foreign body reactions and fibrosis, ^{Reference Kumar14} autologous atrial tissue demonstrates adaptive remodelling. ^{Reference Miyazaki15} This biological integration likely explains the lower pulmonary regurgitation rates observed in Atrial Valve Group at 12 months. The use of the term “RV insufficiency” in this study refers specifically to the combination of moderate or severe pulmonary regurgitation with right ventricular dysfunction, defined as tricuspid annular plane systolic excursion <16 mm or fractional area change <35%, to capture the combined haemodynamic burden post-repair. The reported right ventricular insufficiency rates may appear elevated due to the stringent echocardiographic criteria applied, which are more sensitive than those used in some prior studies. In tetralogy of Fallot repair, transannular patching often results in variable degrees of pulmonary regurgitation, as noted in the literature, ^{Reference Geva3,Reference Valente, Gauvreau and Assenza4} but significant right ventricular dysfunction typically manifests over years rather than within the first year. The higher incidence in No-Valve Group aligns with the greater prevalence of moderate to severe pulmonary regurgitation, reflecting the absence of valve reconstruction. In contrast, Atrial Valve Group’s lower right ventricular insufficiency rate underscores the protective effect of pulmonary valve reconstruction in mitigating pulmonary regurgitation and preserving right ventricular function early post-repair. The stringent criteria used in our study, while potentially inflating early right ventricular dysfunction rates, provide a robust framework for detecting subtle changes in right ventricular performance, highlighting the advantage of valve reconstruction in Atrial Valve Group. The detailed postoperative echocardiographic parameters presented in Table 5 further elucidate the superior right ventricular performance in Atrial Valve Group, with consistently higher tricuspid annular plane systolic excursion and fractional area change values and lower rates of moderate to severe pulmonary regurgitation across all time points compared to No-Valve Group. These findings highlight the protective effect of pulmonary valve reconstruction in mitigating pulmonary regurgitation and preserving right ventricular systolic function, offering a significant advantage over standard transannular patch repair in the early and intermediate post-repair period.

The tailored approach to pulmonary valve reconstruction, accommodating variable right atrial appendage sizes, further enhances the clinical utility of this technique. The need for augmentation with fresh pericardial patch was limited to only 6 of 205 cases (2.9%), indicating that the right atrial appendage was sufficient in the vast majority of patients. This adaptability aligns with prior studies on the versatility of autologous tissues in congenital heart surgery. ^{Reference Ozaki17} The low augmentation rate underscores the reliability of the right atrial appendage as a primary tissue source, ensuring consistent valve functionality across diverse anatomical presentations. In contrast, monocusp valves—while initially effective—often suffer from cusp retraction, where 25% developed moderate pulmonary regurgitation within 6 months. ^{Reference Tanase, Georgiev and Schreiber16} Our findings suggest that right atrial-derived valves may provide more stable mid-term haemodynamic performance than monocusp approaches. Longer follow-up is necessary to determine whether late fibrosis or structural degeneration occurs. Our perioperative outcomes, including longer CPB and ACC times, were offset by shorter ICU stays and reduced pulmonary regurgitation severity. The right atrial appendage’s autologous nature may reduce the risks of long-term calcification compared to monocusp valves. ^{Reference Onan, Ergün, Özturk, Çelik, Ayyıldız and Onan11} The 1-year follow-up period captures critical early outcomes, particularly in resource-limited settings. ^{Reference Onan, Ergün, Özturk, Çelik, Ayyıldız and Onan11} Long-term outcomes of similar techniques using autologous or synthetic materials for pulmonary valve reconstruction provide valuable insights into durability and growth potential. Amirghofran et al. ^{Reference Amirghofran, Edraki and Mehdizadegan23} reported 3-year outcomes of right atrial appendage-based pulmonary valve reconstruction in tetralogy of Fallot patients, noting a stenosis rate of 6% and a regurgitation rate of 10%. Right atrial appendage valve showed limited growth potential, with a reoperation rate of 15% due to progressive regurgitation in paediatric patients, highlighting the challenge of accommodating growth in younger patients. Rawat et al. ^{Reference Rawat, Kumar and Thingnam24} reported 1-year outcomes comparing polytetrafluoroethylene valves with pericardial patch reconstruction in tetralogy of Fallot patients, noting higher stenosis but lower regurgitation with polytetrafluoroethylene. ^{Reference Rawat, Kumar and Thingnam24} The polytetrafluoroethylene valve offered reduced regurgitation but increased stenosis risk, and, being a synthetic material, lacked growth potential, necessitating careful long-term monitoring in paediatric patients. Almousa et al. ^{Reference Almousa25} further emphasised the advantages of autologous tissue in paediatric cardiac surgery, reporting reduced calcification rates compared to synthetic materials, supporting the rationale for using right atrial appendage tissue in our study. Harris et al. ^{Reference Harris26} highlighted growth limitations with autologous approaches. ^{Reference Harris26} Ozaki et al. ^{Reference Tanase, Georgiev and Schreiber16} reported 5-year outcomes of autologous pericardial reconstruction in paediatrics, noting early pulmonary regurgitation rates of 7–10%, but 15% at 5 years due to calcification and limited growth potential. These studies suggest autologous and synthetic valves offer early haemodynamic benefits but lack growth potential in paediatrics, often requiring reintervention. ^{Reference Tanase, Georgiev and Schreiber16,Reference Amirghofran, Edraki and Mehdizadegan23–Reference Harris26} The primary benefit of right atrial appendage-based pulmonary valve (PV) reconstruction is achieving midterm valve competence, reducing chronic pulmonary regurgitation and right ventricular dysfunction. At our most recent follow-up of 12 months, the right atrial appendage-based PV in Atrial Valve Group demonstrated sustained competence, with a significantly lower rate of moderate to severe pulmonary regurgitation (22% ± 7 vs. 37% ± 10, p < 0.01) and no significant increase in right ventricular outflow tract gradient (10.9 ± 3.5 mmHg vs. 11.4 ± 3.8 mmHg, p = 0.15), indicating effective valve function and the absence of residual obstruction (Table 6, Figure 2). These outcomes support the technique’s potential to mitigate the haemodynamic burden of chronic pulmonary regurgitation, as evidenced by reduced right ventricular insufficiency (9.3% vs. 19.8%, p = 0.004) and improved right ventricular systolic function (higher tricuspid annular plane systolic excursion and fractional area change, p < 0.01) at 12 months. In the context of tetralogy of Fallot repair, a 1-year follow-up period is a meaningful time frame for assessing midterm outcomes, capturing critical indicators of valve performance and right ventricular remodelling that are pivotal for long-term prognosis. First, the 12-month period provided a homogeneous cohort with complete, high-quality echocardiographic data at predefined intervals, ensuring statistical reliability. Second, imaging archives for some patients operated on between 2014 and 2017 showed inconsistencies in long-term follow-up data standardisation, prompting us to prioritise the 1-year dataset to maintain methodological integrity. Third, the first 12 months represent a critical window for assessing surgical success, particularly in terms of valve competence, right ventricular function, and early remodelling, which are pivotal in resource-limited settings where growth-compatible autologous valve solutions are increasingly needed. However, recognising the importance of long-term outcomes, we are continuing to monitor both Atrial Valve Group and No-Valve Group patients. A subset of patients (n = 78) is under 5-year analysis for future publication. The absence of significant stenosis or regurgitation at 1-year follow-up is encouraging, but extended follow-up is needed to assess right atrial appendage-based valve durability, growth adaptation, and degeneration resistance. Despite the promising early outcomes, several limitations of the right atrial appendage valve technique warrant discussion. First, surgical excision of the right atrial appendage carries a theoretical risk of atrial arrhythmias due to its anatomical proximity to the sinoatrial node and right coronary artery. Although arrhythmia incidence was low in our cohort, long-term conduction studies are needed. Second, the biological tissue may be prone to fibrosis or structural deterioration over time. Third, morphological variability in right atrial appendage anatomy may preclude consistent replication, especially in younger infants. Future studies should focus on standardising criteria for right atrial appendage selection.

Ozaki’s autologous pericardial trileaflet reconstruction and 3D-printed bioresorbable scaffolds have shown promise in pulmonary valve reconstruction. Ozaki’s technique reports early pulmonary regurgitation rates of 7–10%, ^{Reference Ozaki17} but requires glutaraldehyde fixation, which may pose risks of calcification in paediatric patients. Similarly, 3D-printed scaffolds are innovative but currently limited by high costs and lack of widespread availability. ^{Reference Slater18} While these approaches offer valuable insights, direct comparative studies with our right atrial appendage-based technique are lacking, limiting definitive conclusions about relative efficacy. Future research should focus on head-to-head comparisons to evaluate their performance in similar patient populations.

Atrial Valve Group’s ventilation time and ICU stays were significantly reduced. These reductions translate to significant cost savings. ^{Reference Alimi19} Early extubation reduces the risk of ventilator-associated pneumonia. ^{Reference Gaynor20}

Some may argue that the 7-minute CPB prolongation (Cohen’s d = 0.80) offsets the benefits. However, a 2023 meta-analysis found no correlation between CPB duration <60 minutes and neurodevelopmental outcomes, ^{Reference Lee21} and the effect size is moderate. Arrhythmia rates (4.9%) were low. Unlike other surgeons, ^{Reference Caputo22} we perform right atrial appendage excision after aortic cross-clamping and cardioplegia, without an additional atrial clamp. This approach enhances procedural ease with a clearer surgical field and reduces sinus node and right coronary artery (RCA) damage risk. Ceasing blood flow creates a bloodless field, avoiding stress on the sinus node and RCA. Our experience suggests this simplifies the procedure and lowers injury rates due to better visualisation.

Comparative studies are needed to confirm long-term outcomes. The absence of valve-related reinterventions, thrombus formation, and endocarditis in both groups during the 1-year follow-up supports the short-term safety and feasibility of right atrial appendage-based valve reconstruction. However, long-term studies are needed to confirm the durability of the reconstructed valve and to monitor for potential late complications, such as leaflet degeneration or calcification.

Limited data exist on the long-term outcomes of right atrial appendage-based techniques, particularly regarding growth potential and stenosis or regurgitation. The absence of stenosis or regurgitation at 1-year follow-up is encouraging, but late complications remain uncertain. Long-term studies are needed to evaluate right atrial appendage-based valve growth capacity and monitor for stenosis or regurgitation in paediatrics.