Mediastinal Shift Angle and Its Association with Neonatal Mortality in Fetuses with Isolated Left Congenital...

The mediastinal shift angle (MSA) estimates the lateral displacement of the heart in the fetal thorax. This study aimed to evaluate the MSA's performance in predicting neonatal mortality in fetuses with left isolated congenital diaphragmatic hernia (CDH) as an isolated marker and in combination with other ultrasound and MRI predictors.

MSA was obtained by ultrasound in a cross-sectional four-chamber view of the thorax in 96 fetuses with left isolated CDH. MSA was calculated by drawing two lines from a common point from the skin edge posterior to the spinous process of the thoracic vertebrae, the first line dividing the thorax into two halves, and the second line directed to the lateral border of the right atrium. Additionally, the observed/expected (O/E) lung-to-head ratio LHR, O/E total fetal lung volume (TFLV), and percentage of liver herniation (%LH) were obtained. ROC analysis, prediction, and associations with neonatal mortality were evaluated.

Neonatal mortality was 28.1% (27/96). The areas under (AU) the ROC curve for neonatal mortality for MSA and O/E LHR were 0.69 and 0.75, respectively. The best MSA cutoff value was 35°, with 85.2% sensitivity and 67.1% specificity, and aOR 11.75 (95% CI 3.63-37.97; p < 0.0001). Among fetuses with O/E LHR >25% (n = 75), mortality was 17.5% (13/74). In this subgroup, an MSA ≥35° showed an AU-ROC of 0.72 with 83.3% sensitivity and 71.4% specificity, and an aOR 12.5 (95% CI 2.49-62.76; p = 0.002). There was a significant correlation between MSA and O/E LHR (-0.48, p < 0.001), between MSA and O/E TFLV (-0.36, p = 0.005), and between MSA and %LH (0.43, p = 0.001). However, when MSA and O/E LHR were combined, the AU-ROC for neonatal mortality was 0.832, and when MSA, O/E LHR, and O/E TFLV were combined, the AU-ROC improved to 0.901.

MSA is a good predictor of neonatal mortality in fetuses with left isolated CDH. The prediction improves when MSA, O/E LHR, and O/E TFLV are combined.