OC10.05: *Increased nuchal translucency in congenital heart defects: associations with mortality

Abstract

The objective was to investigate if increased NT was associated with increased mortality in children with CHD. In a nationwide cohort using population-based registries, 5,633 liveborn children in Denmark with a pre or postnatal diagnosis of CHD from 2008-2018 (0.7%) were identified. Children with lack of data on first trimester screening, chromosomal abnormalities or no match between registries were excluded. Increased NT was defined as NT > 3.5 mm or NT > 1.5 Multiples of Median (MoM). Proportions were compared using chi-squared test with a significance level of 0.05. Of 4,469 children with CHD eventually included in the cohort, 754 (17%) had complex CHD and 3,715 (83%) simple CHD. Of these, 239 (5.3%) had an NT >1.5 MoM, and 57 (1.3%) an NT >3.5 mm. Mortality was higher in CHD with NT >1.5 MoM than NT <1.5 MoM (3.3% vs. 1.5%, p = 0.03). Mortality was increased for simple CHD when NT was >1.5 MoM (2.3% vs 0.6%, p = 0.01). Amongst simple CHD undergoing surgery a significantly higher mortality was found in the group with NT >1.5 MoM (8.6% vs 2.5%, p = 0.04). Complex CHD was more frequent in the group of NT >1.5 MoM than NT <1.5 MoM (27% vs. 16%, p < 0.01), but NT >1.5 MoM was not associated with higher mortality (6.1% vs. 5.8%, p = 0.93) Amongst complex CHD undergoing surgery there was no difference in mortality between NT >1.5 MoM and NT <1.5 MoM (4.3% vs. 7.5%, p = 0.44). Due to limited numbers the association to mortality in the group with NT >3.5 mm could not be assessed. Confounding birth variables: gestational age, birthweight, small for gestational age, preterm birth, pre-eclampsia, placental weight, maternal smoking, maternal BMI, beta-HcG, and PAPP-A were equally distributed between NT >1.5 and <1.5 MoM. In children born with CHD, an increased NT was associated with increased mortality. The association was primarily evident in infants with simple CHD. Increased NT could possibly be an independent predictor of increased mortality in children with CHD.