Preoperative pulmonary valve annulus diameter z score as a predictor of pulmonary regurgitation after tetralogy of Fallot repair: a retrospective cohort study

Tetralogy of Fallot (ToF) is the most common cause of cyanotic congenital heart disease and pulmonary regurgitation (PR) remains its most frequent postoperative complication. The preoperative z score of the pulmonary valve annulus (PVA) has been associated with an increased risk of 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 MSCT-derived PVA diameter z score for early PR after ToF repair. This 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 using cardiac multislice computed tomography (MSCT). Early PR was assessed via echocardiography within 45 days post-operatively. Multivariable logistic regression was performed and receiver operating characteristic (ROC) curve analyses were performed. A total of 101 subjects were analysed. Both maximal and minimal diameters of the PVA z scores were associated with moderate or greater PR in the univariate analysis ( p = 0.001 and p < 0.001, respectively). However, in multivariate analysis, only transannular patch (TAP) remained an independent predictor ( p < 0.001), while PVA z scores were no longer statistically significant. 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, with high specificity (90.6%) but limited sensitivity (42%). Preoperative PVA z score is associated with early PR but does not independently predict the outcome after adjustment, as its effect is largely mediated by surgical strategy, particularly the use of TAP. While the proposed cut-off of − 2.5 demonstrates high specificity, its low sensitivity limits its utility as a screening tool. PVA z score should therefore be interpreted alongside intraoperative factors rather than used as a standalone predictor of postoperative PR, as it reflects a preoperative anatomical parameter that influences surgical decision-making.