EP06.02: Fetal esophagus: biometry, feasibility of 2D and 3D ultrasound evaluation and a new marker for esophageal atresia in second trimester

To obtain fetal upper esophagus biometry and to identify a second trimester marker referable to a subsequent “esophageal pouch” (EP) and to a postnatal diagnosis of esophageal atresia (AE). Single physiological pregnancies between 19 and 23 weeks were consecutively enrolled. 2D-US and 3D-US studies of upper esophagus (epiglottis stem-tracheal carina tract) were performed by 3 operators. Esophagus thickness was sampled at 3 levels: ‘P1’ (at epiglottis stem), ‘P3’ (at tracheal carina) and ‘P2’ (halfway point between the two or at the maximum thickness between ‘P1’ and ‘P3’). Patients were allocated on the absence (Group 1-G1) or presence (Group 2-G2) of an inhomogeneity of the calibre, defined arbitrarily as “P2”> “P1 + 1.5 mm”. Outcomes were compared considering a significant p-value<0.05. Among 205 patients enrolled, the upper esophagus was visible in 187 cases. The medians (range) of this tract biometry were acquired (length and ‘P1’, ‘P2’, ‘P3’ width). The minimum number of scans required to become competent (by CUSUM analysis, K = 0.15) was 17 and 45 cases depending on the operator training. A preserved length was demonstrated in all cases. A normal calibre was found in 180 cases (G1- 96.3%). In G2 (7 cases- 3.7%) a thickened ‘P2’ was found as at least > 2 times the expected median (range), significantly >95^ centile (p value< 0.0339) and always >3 mm. In whole G1, postnatal course was regular. In G2 an EP appeared in third trimester with confirmation of neonatal AE in 6 out of 7 cases (VPP: 85.7%), an association between inhomogeneous calibre and small stomach was found in 57.1% (vs. 0% in G1, p value <0.001) and with polyhydramnios in 83.3% (vs. 1,57% in G1, p value< 0.001). A thickening in “P2” correlates with a subsequent EP and AE. Upper esophagus can be assessed and measured. An homogeneous upper esophagus relates with a high-negative predictive value for AE. Given the rarity of the disease and the small numbers, further studies are needed to confirm our results.