[Analysis of optimizing indications for fetal pulmonary valvuloplasty based on a multi-parameter scoring system]

Objective: To establish a multi-parametric scoring system for predicting postnatal circulatory outcomes in fetuses with critical pulmonary stenosis (CPS) and pulmonary atresia (PA) with intact ventricular septum (IVS), in order to optimize the indications for fetal pulmonary valvuloplasty (FPV). Methods: This was a retrospective cohort study. A total of 96 fetuses diagnosed with CPS-IVS or PA-IVS at Women and Children's Hospital, Qingdao University between July 2018 and June 2021 were included. Fetuses who did not undergo FPV constituted the modeling cohort, while those who underwent FPV constituted the validation cohort. Fetuses were classified into biventricular and non-biventricular circulation groups based on postnatal circulatory outcomes. Prenatal fetal echocardiographic parameters were compared between groups using independent-samples t test, Mann-Whitney U test, χ² test or Fisher exact test. Based on inter-group differences, parameters associated with postnatal circulatory outcomes were screened in the modeling cohort. For continuous variables, optimal cut-off values were determined using receiver operating characteristic (ROC) curve and the Youden index and then dichotomized. Right ventricular endocardial fibroelastosis (EFE) was graded as 0, 1 or 2 according to severity. OR of each parameter were calculated, and a multiparametric scoring system was constructed. ROC curve was used to evaluate its predictive performance. Post-FPV outcome improvement was assessed in the validation cohort. Results: Among the 96 fetuses, 78 were assigned to the modeling cohort and 18 to the validation cohort. Postnatally, biventricular circulation was achieved in 56 cases (72%) in the modeling cohort and 13 cases in the validation cohort. In the modeling cohort, the right ventricular long-axis/left ventricular long-axis (RV/LV), tricuspid annulus diameter/mitral annulus diameter (TV/MV) and pulmonary valve annulus/aortic valve annulus (PV/AV) in the non-biventricular group were lower than that in the biventricular group (all P<0.05). The optimal cut-off values for predicting postnatal circulatory outcomes were 0.65, 0.82 and 0.78, respectively. There was statistically significant difference in the distribution of circulatory outcomes between fetuses with grade 2 EFE and those with no or grade 1 EFE (χ²=21.28, P<0.001). Therefore, right ventricular EFE was dichotomized in the model as "none or grade 1" versus "grade 2". Each parameter was assigned a corresponding weight based on its OR value, and an integer score was obtained to construct the scoring system: grade 2 right ventricular EFE was assigned 5 points, RV/LV≤0.65 was assigned 2 points, TV/MV≤0.82 was assigned 2 points, and PV/AV≤0.78 was assigned 1 point, with a maximum total score of 10 points. At cut-off scores of 3, 4, and 5 points, the areas under the curve were 0.88, 0.91, and 0.88, respectively, with the highest specificity (0.95, 95% CI 0.84-0.99) observed at a score threshold of 5 points. In the validation cohort, 15 fetuses had scores ≥5 points, among whom 10 fetuses achieved biventricular circulation after birth, whereas in the modeling cohort, only 1 of 18 fetuses achieved biventricular circulation after birth. Conclusions: A multiparametric scoring system based on prenatal fetal echocardiographic parameters can effectively predict non-biventricular postnatal outcomes in fetuses with CPS-IVS and PA-IVS. By identifying high-risk patients, the indications for FPV can be optimized.