Two- and three-dimensional imaging of coarctation shelf in the human fetus

How often an isolated cardiac disproportion predicts a coarctation of the aorta? Single center experience and systematic review of the literature

BACKGROUND

Cardiac disproportion is considered as an indirect sign of coarctation of the aorta (CoA). In this review, we have reassessed the positive predictive value (PPV) of such finding for a postnatal confirmation of CoA.

DATA SOURCES

All cases of isolated cardiac disproportion diagnosed in the four-chamber and/or three-vessel/three-vessel and trachea views (right/left sections >1.5) were included. Postnatal cardiac findings were recorded. Additionally, a systematic literature search (PubMed, EMBASE, Cochrane library, and the reference lists of identified articles) regarding the association between antenatally detected cardiac disproportion and postnatal confirmation of CoA was performed. Data from our center were pooled with those derived from the literature.

RESULTS

Ten fetuses with isolated cardiac disproportion were selected from our center and 259 from the literature review. CoA was postnatally confirmed in 101/269 (PPV 38%). PPV of antenatal cardiac findings was significantly higher in earlier gestation (23/27, 85% <26⁺⁰weeks versus 11/39, 28%≥26⁺⁰weeks, p < .001). No significant difference was noticed comparing ventricular disproportion with combined ventricular and great vessels disproportion (86/230 versus 15/39, p  .89).

DISCUSSION

Isolated cardiac disproportion has an overall chance of one in three of heralding a CoA in the neonate. The specificity of these findings is significantly higher in the second trimester.

Fetal diagnosis of interrupted aortic arch

To determine the frequency of prenatal detection among liveborn patients with an interrupted aortic arch (IAA), the accuracy of prenatal diagnosis, and the anatomic features associated with IAA in the fetus. The prenatal diagnosis of an IAA is challenging. The data on the features and outcomes of fetal IAA are limited. This was a retrospective review of the fetuses and neonates diagnosed with IAA at the Children's Hospital Boston. From 1988 to 2009, 26 fetuses were diagnosed with an IAA. Of these, 21 were live born, and 5 pregnancies were terminated. Of these 21 patients, 18 were confirmed to have an IAA after birth and 3 had severe aortic coarctation. Of the 56 patients diagnosed with an IAA as neonates, 3 had a prenatal echocardiogram that did not include the correct diagnosis. Among the liveborn patients with a postnatally confirmed IAA, 24% were diagnosed prenatally, which increased from 11% during the first 7-year period to 43% more recently. Also, 15% of the prenatally diagnosed patients with IAA had a family history of structural or genetic anomalies. In fetuses with an IAA, echocardiographic Z-scores for the aortic valve and ascending aorta were significantly lower than in normal fetuses, but the left ventricular dimensions were normal. Aortopulmonary diameter ratios were abnormally low. In conclusion, although the identification of IAA on a prenatal echocardiogram can be challenging, a number of anatomic features can facilitate the diagnosis. In particular, a low aortopulmonary diameter ratio in the absence of a ventricular size discrepancy should prompt consideration of this diagnosis. Despite the diagnostic challenges, the frequency of prenatal diagnosis of the IAA is increasing.

Measurement of the great vessels in the mediastinum could help distinguish true from false-positive coarctation of the aorta in the third trimester

OBJECTIVE

We investigated the utility of analyzing prenatal mediastinal measures of the great arteries in distinguishing true coarctation of the aorta (CoA) from false-positive CoA.

METHODS

All fetuses in this study had suspicion of CoA based on the presence of right-left heart disproportion. We defined 3 study groups: group 1, true fetal CoA; group 2, false-positive fetal CoA with a narrow aortic arch; and group 3, false-positive fetal CoA without a narrow aortic arch.

RESULTS

In group 1, the mean mediastinal pulmonary artery (PA) to ascending aorta (Ao) diameter ratio +/- SD was 2.03 +/- 0.48, and in group 2, the ratio was 1.60 +/- 0.23. The difference was statistically significant (P = .0018, t test). In group 3, the mean PA:Ao ratio was 1.35 +/- 0.14. The difference between groups 1 and 3 was statistically significant (P = .0002, t test). In our study group, for a PA:Ao ratio of 1.60, sensitivity was 83.0%; specificity, 85.0%; positive predictive value, 62.5%; and negative predictive value, 94.0%.

CONCLUSIONS

In the third trimester, the main PA:Ao ratio as measured in the fetal mediastinum can be a helpful tool in distinguishing true CoA requiring neonatal cardiac surgery from false-positive CoA and simple disproportion requiring medical attention but no surgery in the first month of postnatal life.