Prediction of postnatal treatment strategy in fetuses with isolated pulmonary stenosis

Background: Fetuses with pulmonary stenosis (PS) may undergo surgical valvulotomy, pulmonary valvuloplasty via interventional catheterization or expectant management after birth, a predictive model for the possibility of surgery has not yet been established in previously published reports. This study aims to identify prenatal prognostic factors for a postnatal management approach in fetuses with isolated PS in a retrospective cohort of non-intervened fetuses between 24 and 34 weeks and to evaluate its performance prospectively. Methods: Baseline characteristics and outcomes of the study population were recorded. Prenatal cardiac and hemodynamic parameters were stratified by postnatal intervention treatment (surgical valvulotomy or percutaneous balloon pulmonary valvuloplasty) or expectant treatment at 1 year of age after birth. Classification and regression tree analysis was conducted to investigate the predictive capacity of prenatal echocardiographic parameters for postnatal treatment strategy at 1 year of age. We also prospectively validated it in the fetuses with isolated PS. Results: A total of 71 live-born fetuses with isolated PS were enrolled from January 2014 to September 2022 in our institution for model construction. Among them, 37 received postnatal intervention treatment, including 17 who underwent surgical valvulotomy and 20 who underwent percutaneous balloon pulmonary valvuloplasty. The classification and regression tree model based on the right ventricular (RV) pressure, which was recorded as the maximum velocity of tricuspid valve regurgitation (TR-Vmax) combined with the RV/left ventricular (LV) length ratio and prenatal peak systolic velocity of the pulmonary valve (PV-PSV), showed a sensitivity of 100% and specificity of 100% for predicting postnatal outcomes. The highest probability of postnatal intervention treatment was attained for fetuses with TR-Vmax >135.5 cm/s (100%). The predictors were validated in another 10 fetuses from October 2022 to August 2023 in our institution prospectively. The sensitivity was 100% and specificity was 100% for predicting postnatal treatment strategy. Conclusions: Prenatal RV pressure estimates, which were demonstrated as TR-Vmax combined with the RV/LV length ratio and PV-PSV, could predict the postnatal management strategy for isolated PS with high sensitivity and specificity.