Objective: The false-positive rate for prenatal diagnosis of coarctation of the aorta (FP-CoA) commonly exceeds 50%, with an accurate detection rate of < 50%. This study was conducted to determine if the sensitivity for prenatal detection of true CoA and the FP-CoA rate could be improved by evaluating the fetal epicardial size and shape in the four-chamber view (4CV) and the endocardial right (RV) and left (LV) ventricular size, shape and contractility.
Methods: We analyzed retrospectively Digital Imaging and Communications in Medicine (DICOM) clips of the 4CV from the last examination prior to delivery in a series of 108 fetuses with CoA suspected prenatally by pediatric cardiologists using traditional diagnostic criteria. Postnatal evaluation distinguished those fetuses which subsequently required CoA surgery (true positives; true CoA) from those that were FP-CoA. Postnatal cardiac abnormalities were identified for each group. For the prenatal evaluation, we measured the 4CV end-diastolic epicardial area, circumference, length, width and global sphericity index. Speckle-tracking analysis was used to compute the endocardial RV and LV end-diastolic area, length, 24-segment sphericity index, 24-segment transverse width and the following functional parameters: fractional area change; global longitudinal, free-wall and septal-wall strain; basal-apical-length, basal free-wall and basal septal-wall fractional shortening; septal-wall annular plane systolic excursion; 24-segment transverse-width fractional shortening; and LV end-diastolic and end-systolic volumes, stroke volume, cardiac output and ejection fraction. In addition, the RV/LV end-diastolic area ratio was computed. Using a control group of 200 normal fetuses, the mean and SD for each of the above cardiac measurements was used to compute the Z-scores for each measurement in each of the 108 study fetuses. Logistic regression analysis was then performed on the Z-score values to identify variables that separated the true CoA group from the FP-CoA group.
Results: Of the 108 study fetuses, 54 were confirmed postnatally to have true CoA and 54 were FP-CoA. Right/left area disproportion > 90th centile was present in 80% (n = 43) of the true-CoA fetuses and 76% (n = 41) of the FP-CoA fetuses. Fetuses with true CoA had a significantly greater number of associated cardiac abnormalities (93%, n = 50) compared with the FP-CoA fetuses (61%, n = 33) (P < 0.001). The most common associated malformations were bicuspid aortic valve (true CoA, 46% (n = 25) vs FP-CoA, 22% (n = 12); P < 0.01), aortic arch hypoplasia (true CoA, 31% (n = 17) vs FP-CoA, 11% (n = 6); P < 0.01), ventricular septal defect (true CoA, 33% (n = 18) vs FP-CoA, 11% (n = 6); P < 0.05) and mitral valve abnormality (true CoA, 30% (n = 16) vs FP-CoA, 4% (n = 2); P < 0.01). Logistic regression analysis identified 28 variables that correctly identified 96% (52/54) of the fetuses with true CoA, with a false-positive rate of 4% (2/54) and a false-negative rate of 4% (2/54). These variables included the epicardial size in the 4CV, size and shape of RV and LV, and abnormal contractility of RV and LV. The area under the receiver-operating-characteristics curve was 0.98 (SE, 0.023; 95% CI, 0.84-1). There was no significant difference in the percent of fetuses with RV/LV area disproportion between those with CoA and those that were FP-CoA.
Conclusions: Speckle-tracking analysis of multiple ventricular measurements may be helpful to refine the diagnosis in fetuses that are suspected to have CoA prenatally. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.
Keywords: CoA; coarctation of the aorta; congenital heart defect; fetal echocardiography; logistic regression; prenatal diagnosis; speckle tracking; strain.
© 2020 International Society of Ultrasound in Obstetrics and Gynecology.