Value of pulmonary annulus area index in predicting transannular patch placement in tetralogy of Fallot repair.

Background Precisely evaluating the need for transannular patch (TAP) placement is very important in the surgical treatment of tetralogy of Fallot. We hypothesized that the pulmonary annulus area index (PAAI, the pulmonary-to-aortic valve annulus cross-sectional area ratio) could be a useful and accessible predictor for TAP placement. Methods The medical records of patients who underwent tetralogy of Fallot repair between 1 January 2016 and 31 December 2017 were reviewed retrospectively. A total of 255 patients were included and categorized into two groups: patients who needed TAP placement and patients who did not. Various candidate predictors for TAP placement (PAAI, pulmonary annulus z-score, and velocity across the pulmonary annulus) were compared using receiver operating characteristic curves. The optimal cutoff for each predictor was assessed. Results Among the 255 patients included, 156 needed TAP placement (156/237, 65.8%). Both the PAAI (0.28 [0.20/0.34] vs 0.14 [0.09/0.19]; P < .0001) and z-score (-1.5 [-2.9, -0.4] vs -3.6 [-5.3/-2.6]; P < .0001) were smaller in the TAP group. The PAAI is a useful predictor of the pulmonary annulus z-score (AUC 0.830 vs 0.811, P = .19). Combination analysis of the PAAI and velocity across the pulmonary annulus (PV v(max)) showed better predictive value than the PAAI and z-score (AUC 0.860, sensitivity 89.7%, specificity 61.7%, P < .0001). Conclusions Our results suggest that the PAAI is a useful and accessible predictor for TAP placement and can be applied readily and simply in clinical practice. A combination with the velocity across the pulmonary annulus could promote the accuracy of prediction.