Accuracy of fetal echocardiography in detecting lesions associated with, and predicting surgical plan for, dextro‐transposition of the great arteries and double outlet right ventricle with subpulmonary ventricular septal defect and predicted transposition physiology

ABSTRACT Objectives In dextro‐transposition of the great arteries (D‐TGA) and double outlet right ventricle with subpulmonary ventricular septal defect (DORV‐SPV) and predicted transposition physiology, the presence of associated lesions, such as ventricular septal defect (VSD), coarctation of the aorta (CoA) or pulmonary stenosis (PS), impacts prenatal counseling and complicates neonatal surgery. This study aimed to evaluate the diagnostic accuracy of fetal echocardiography (FE) and its ability to predict the postnatal surgical plan in fetuses with D‐TGA or DORV‐SPV. Methods This was a single‐center retrospective cohort study of fetuses with D‐TGA or DORV‐SPV who were liveborn, had a recorded plan for postnatal intervention and were managed at Lucile Packard Children's Hospital, Palo Alto, CA, USA, between January 2013 and January 2024. In cases with serial FE examinations, all available FE reports were included in the analysis, in addition to the first postnatal echocardiogram report. For echocardiograms with incomplete measurement data, a single reader retrospectively obtained FE and postnatal echocardiogram measurements while blinded to clinical outcomes. Prenatal predictions for postnatal surgical repair were extracted from the fetal cardiology consultation notes and postnatal clinical data were obtained by chart review. Final FE and postnatal echocardiogram diagnoses, as well as prenatal surgical‐plan predictions and subsequent postnatal surgical repairs performed, were compared and the percentage concordance was calculated to obtain FE diagnostic accuracy. Receiver‐operating‐characteristics (ROC) curves were generated to evaluate the association of FE aortic and pulmonary measurements with postnatal CoA repair. Results The study included 99 fetuses, of which 45 were diagnosed postnatally with simple D‐TGA with no associated lesions (i.e. D‐TGA with intact ventricular septum), 38 with complex D‐TGA with associated lesions and 15 with DORV, and one neonate was diagnosed prenatally with DORV‐SPV but postnatally diagnosed with truncus arteriosus. In the majority (65%) of patients, serial FE was performed. The percentage concordance between fetal and postnatal echocardiogram diagnoses was high for simple D‐TGA (95% (42/44)) and D‐TGA with VSD and PS (100% (3/3)). The concordance was progressively lower for diagnoses of D‐TGA with VSD (93% (25/27)), DORV‐SPV (60% (3/5)), DORV‐SPV with CoA (40% (4/10)), D‐TGA with VSD and CoA (29% (2/7)), D‐TGA with isolated CoA (0% (0/2)) and DORV‐SPV with PS (0% (0/1)). Similarly, surgical‐plan accuracy between prenatal prediction and postnatal repair performed was highest for cases of simple D‐TGA and D‐TGA with VSD and PS, while it was lower for other diagnoses. Qualitative descriptions of VSD size changed frequently over serial FE examinations, with VSDs generally described as larger on later FE. However, between the final FE and postnatal echocardiogram, in those with discordance, the description of VSD size usually became smaller. Only 50% of small VSDs identified on postnatal echocardiography required repair. All patients who underwent postnatal repair of CoA had a VSD present. All area under the ROC curve values for aortic measurements and for ratios of aortic‐to‐pulmonary dimensions in predicting the need for postnatal CoA repair were greater than 0.9. Conclusions Challenges remain in the accurate diagnosis and prediction of the postnatal surgical plan in fetuses with complex D‐TGA and DORV‐SPV. The assessment of qualitative VSD size description changed frequently over serial FE evaluations, and between final FE and postnatal echocardiogram, with small defects often not requiring repair. Aortic and aortic‐to‐pulmonary ratio measurements in fetuses with D‐TGA or DORV‐SPV appear to have improved the discriminatory ability in identifying cases that undergo postnatal CoA repair relative to fetuses with isolated CoA. © 2026 International Society of Ultrasound in Obstetrics and Gynecology.