To summarize the prenatal echocardiographic diagnostic features, hemodynamic characteristics, and associated extracardiac vascular anomalies of fetal pulmonary atresia (PA), including pulmonary atresia with intact ventricular septum (PA-IVS), pulmonary atresia with ventricular septal defect (PA-VSD), and pulmonary atresia with functional single ventricle (PA-FSV), and to establish a systematic diagnostic approach for fetal PA.

A retrospective analysis was conducted on 297 fetuses diagnosed with PA (including PA-IVS, PA-VSD, and PA-FSV) by prenatal echocardiography between January 2017 and November 2025. The following features were assessed across the three groups: the level of pulmonary outflow obstruction (valvular vs main pulmonary artery), severity of tricuspid regurgitation (TR), sources of pulmonary blood flow, ventricular development in the PA-IVS and PA-VSD groups, and the presence of right ventricle–dependent coronary circulation (RVDCC). In addition, the incidence of associated extracardiac vascular anomalies—such as aortic arch abnormalities and systemic venous anomalies—was compared among the three groups. Group differences in the site of occlusion, right ventricular morphology, tricuspid regurgitation, and sources of pulmonary blood supply were compared using the χ² test or Fisher's exact test, as appropriate.

Among the 297 fetuses with PA, 94 were classified as having PA-IVS, 177 had PA-VSD, and 26 had PA-FSV. Significant differences were observed among the three groups with respect to the level of pulmonary atresia (valvular/main trunk: 71/23 vs 20/157 vs 2/24) and sources of pulmonary blood supply (anterior descending coronary artery perfusion/main-pulmonary collateral circulation/combination of both: 93/1/0 vs 137/29/11 vs 22/4/0) (all P<0.05). Furthermore, significant differences were identified between the PA-IVS and PA-VSD groups regarding TR severity and corresponding right ventricular morphology (all P<0.05); the PA-IVS group predominantly exhibited severe TR (68/74, 72.4%) in association with right ventricular hypoplasia (82/94, 87.2%), whereas the PA-VSD group mainly showed non-severe TR (168/177, 94.9%) with balanced ventricular development (166/177, 93.8%). All 13 cases of RVDCC occurred in the PA-IVS group and were uniformly associated with right ventricular hypoplasia; among these, 3 cases (23.1%) had severe TR, 5 (38.5%) had non-severe TR, and 5 (38.5%) had no TR. With respect to extracardiac vascular anomalies, the PA-VSD group demonstrated significantly higher rates of right aortic arch, persistent left superior vena cava, and innominate vein anomalies compared with the PA-IVS group (24.3% vs 1.1%, 30.5% vs 5.3%, and 35.6% vs 5.3%; χ²=24.464, 24.284, and 30.421, respectively; all P<0.001).

Fetal pulmonary atresia exhibits distinctive prenatal ultrasonographic features. Comprehensive assessment of ventricular septal integrity, right ventricular morphology, and tricuspid regurgitation facilitates an integrated understanding of intracardiac hemodynamics, thereby improving diagnostic accuracy and informing subsequent clinical management and genetic counseling.