Preoperative Pulmonary Valve Annulus Diameter Z Score as a Predictor of Pulmonary Regurgitation after Tetralogy of Fallot Repair: A Retrospective Cohort Study

Background Tetralogy of Fallot (ToF) is the most common cause of cyanotic congenital heart disease and pulmonary regurgitation (PR) remains the most frequent complication after ToF repair, affecting a patient’s long-term prognosis. The preoperative z score of the pulmonary valve annulus (PVA) has been shown to be associated with an increased risk of significant PR after ToF repair; however, the optimal cut-off value varies among studies and has not been investigated in the Indonesian population. This study aimed to determine the predictive value of the preoperative PVA z score diameter for the occurrence of PR after ToF repair. Methods A retrospective cohort study was conducted using secondary data from pediatric patients who underwent ToF repair at the National Cardiac Center Harapan Kita between January 2023 and December 2024. The preoperative PVA diameter was measured via cardiac multislice computed tomography (MSCT). The outcome, early PR, was assessed via echocardiography within 45 days post-operatively. Multivariable logistic regression was performed and receiver operating characteristic (ROC) curve analyses were used to identify optimal cut-off values. Results A total of 101 subjects were analysed. There was a significant association between the maximal and minimal diameters of the PVA z scores (p = 0,001 and p < 0,001, respectively) with significant PR in the univariate analysis. Multivariate analysis revealed that only the minimal diameter of the PVA z-score remained significant (p < 0,001). ROC analysis revealed that the minimal diameter of the PVA z score (area under the curve [AUC] 0,701; cut-off − 2,5) demonstrated moderate discriminatory ability in predicting early PR, with high specificity (90,6%) but limited sensitivity (42%). Conclusion The z score of the PVA minimal diameter, measured by preoperative MSCT, was consistently associated with early significant PR after ToF repair and may assist early risk stratification, although its predictive value should be interpreted alongside other clinical and intraoperative factors.