Tuo G, Paladini D, Marasini L, Buratti S, De Tonetti G, Calevo MG, Marasini M.Front Pediatr. 2022 Oct 10;10:866994. doi: 10.3389/fped.2022.866994. eCollection 2022.PMID: 36299692
Commentary from Dr. Manoj Gupta (New York City, NY, USA), chief section editor of Pediatric & Fetal Cardiology Journal Watch.
Take home points:
- Aortic valve (AV) z-score and distal transverse aortic arch (TAA) z-score resulted as the best predictors of CoA after birth. The best cutoff point for CoA discrimination with ROC analysis was an AV z-score of −1.25 and a distal TAA z-score of −0.37.
- The current criteria for diagnosing CoA in utero allow accurate diagnosis of most severe cases but the rate of false positives remains relatively high for milder cases.
CoA occurs in 7–8% of newborn children with congenitally malformed hearts and is a cause of remarkable morbidity and mortality if not diagnosed early. It has already been demonstrated that the diagnosis of prenatal CoA improves perioperative condition and survival of affected neonates by allowing planned delivery in a tertiary care center and early institution of prostaglandin treatment to prevent the closure of the duct.
Several echocardiographic measurements have already been proposed to improve the detection rate of prenatal diagnosis of CoA, including two-dimensional measurements of the ventricular inflow and outflow tracts and the derived z-scores, the comparison of left and right-side structure diameters, Doppler signs, and other features like the presence of a persistent left superior vena cava (LSVC), the visualization of a juxta-ductal shelf, and the carotid subclavian index.
The following retrospective measurements were carried out: mitral valve (MV) z-score; mitral/tricuspid valve (MV/TV) ratio; left/right ventricular (LV/RV) diameter ratio; aortic valve (AV) z-score; aortic/pulmonary valve (AV/PV) ratio; main pulmonary artery/ascending aorta ratio (MPA/AA); distal transverse aortic arch (TAA) and aortic isthmus diameter (AI) z-score; aortic isthmus/arterial duct (AI/AD) ratio. Color Doppler assessment of flow, respectively, at the aortic arch (antegrade flow alone or antegrade and reversed ductal-dependent flow) and at the foramen ovale (right to left or bidirectional) were recorded.
Low CoA risk fetuses received the first diagnosis of CoA suspicion during the third trimester of pregnancy (> 28 weeks of GA, late diagnosis), had an aortic isthmus narrowing (-3 < isthmus z-score ≤-2; 0.5 < AI/AD ratio < 0.7) but a good size transverse aortic arch at the subjective analysis, and a mild discrepancy between the right and left side structures (LV/RV ratio ≥0.6).
Moderate CoA risk fetuses received an early diagnosis (<28 weeks of GA), had an aortic isthmus narrowing (isthmus z score <-3, AI/AD ratio LV/RV ratio ≤0.5) and a more evident discrepancy between left and right side dimensions both at the level of the ventricles (mitral z-score <-3, LV/RV ratio < 0.6) and of the great arteries (MPA/AA ratio 2) compared to the low CoA risk fetuses.
High risk fetuses presented moderate-risk anatomic features with marked hypoplasia of the aortic arch (distal TAA z-score <- 1), a borderline LV with MV hypoplasia (z-score <-5), and an aortic arch flow reversal and bidirectional flow at the level of the foramen ovale.
102 consecutive fetuses with a suspicion of CoA in the second or third trimester of pregnancy were identified. Six pregnancies were terminated: three for the development of Shone’s syndrome, two for CoA suspicion in Turner’s syndrome, and one for CoA associated with hydrops fetalis. Five fetuses were lost at prenatal cardiac follow-up. The study population included 91 newborn fetuses (Table 1). Of which, 27 (30%) were confirmed with CoA after birth and underwent surgical procedures within the first month of life. CoA risk was prenatally estimated to be high in 22 out of 27 of them and moderate in 5 out of 27. Among the other 64/91 fetuses that did not develop CoA after birth, 24/64 were prenatally considered to have a moderate CoA risk and 40/64 a low CoA risk.
The comparative analysis between newborns with confirmed or without confirmed surgical CoA is detailed in Table 2
The best cutoff point for CoA discrimination with ROC analysis was an AV z-score of −1.25 and a distal TAA z-score of −0.37. The parameter with the greatest sensitivity and specificity was the distal TAA z-score ≤-0.37 with 96.3 and 81.2%, respectively.
Discussion and Conclusion
In our experience, the cardiovascular disproportion between the left and right cardiac structures and the predominance of the right carries an increased risk for the occurrence of CoA, especially if already evident during the ultrasound evaluation in the second trimester. The statistical analysis defined AV z-score and distal TAA z-score as the best predictors of CoA after birth.