Accuracy of Fetal Echocardiography in Defining Anatomic Details: A Single-Institution Experience over a 12-Year Period

Background: Fetal echocardiography has evolved over four decades, now permitting the prenatal diagnoses of most major congenital heart disease (CHD). To identify areas for targeted improvement, the authors explored the diagnostic accuracy of fetal echocardiography in defining major fetal CHD. Methods: All fetuses with major fetal CHD (11 subtypes) at a single institution between 2007 and 2018 were identified (n = 827). Fetal echocardiography reports were compared with postnatal imaging and surgical or autopsy reports, and findings were categorized as follows: category 1, no errors; category 2, minor errors without impact on care, considered “accurate”; category 3, errors with minor impact on surgical approach; and category 4, errors with major impact on neonatal care or outcomes, considered “inaccurate.” In addition, the contributions of era, gestational age at first fetal echocardiography, serial fetal echocardiography, maternal weight, and reviewer level of training were examined. Results: Of 589 fetuses with autopsy or postnatal confirmation, accurate diagnoses were made in 530 (90%). The highest rates of accuracy were observed in univentricular hearts (97.6%; 95% CI, 87.4%-99.6%), tetralogy of Fallot (97.2%; 95% CI, 90.0%-99.2%), and transposition of the great arteries (96.1%; 95% CI, 89.2%-98.6%), and the lowest were observed in double-outlet right ventricle (81.1%; 95% CI, 70.4%-88.6%), truncus arteriosus (72.7%; 95% CI, 51.8%-86.8%), and heterotaxy (71.1%; 95% CI, 56.6%-82.2%). Greater accuracy was associated with later diagnostic era (2012-2018, P =.026), first fetal echocardiography at ≤25 weeks (P =.028), and formal fetal cardiology training of the reviewer (P =.001). Maternal pre-pregnancy weight did not affect accuracy. Conclusions: The diagnostic accuracy of fetal echocardiography for major CHD is high, particularly in the hands of fetal cardiology–trained practitioners. There are lesion-specific as well as general modifiable and nonmodifiable factors that affect diagnostic accuracy.