OC09.01: Growth curve for aortic arch in perinatal period: revealing patterns of vascular remodelling under altered circulation patterns

To establish aortic isthmus growth curve in normal population from 28 weeks gestation to 52 weeks after birth, and to reveal normal remodelling pattern of isthmus, which provides a basis for prenatal prediction of aortic coarctation. A retrospective birth cohort, containing normal fetuses in the third trimester, newborns, and infants from four medical centres, was constructed. A total of 5,726 individuals were included, including 4,712 fetuses and 1,014 neonates and infants. Isthmus diameter was measured according to ASE guidelines. Correction for fetuses' gestational weeks was completed by biological parameters. Residuals of common least squares regression models didn't conform the normal distribution, so, quantile regression model was used to construct growth curves. Five-fold five times cross-validation was applied to select optimal fitting model to mine the remodelling features of aortic isthmus in perinatal period. Isthmus diameter increased uniformly with gestational age before birth, larger isthmus diameter correlated with higher growth rates (10th percentile: 0.063 mm/week, 50th percentile: 0.112 mm/week; 90th percentile: 0.155 mm/week); during the first 5 weeks after birth, growth rate increased rapidly, significantly greater than the prenatal period, and sharply decreased after 5 weeks, smaller isthmus diameter correlated with higher growth rates (10th percentile: 0.350 mm/week; 50th percentile: 0.264 mm/week; 90th percentile: 0.223 mm/week); after 5 weeks postpartum, isthmus diameter increased steadily with age, although pace was significantly slower than the initial phase, tlarger isthmus diameter correlated with higher growth rates (10th percentile: 0.007 mm/week; 50th percentile: 0.038 mm/week; 90th percentile: 0.044 mm/week). We established aortic isthmus growth curve, and revealed features of isthmus remodelling in perinatal period in a large sample, which assists in prenatal prediction of normal changes of isthmus after birth and reduction of false-positive prenatal diagnosis.