517: Low body-mass-index is a risk factor for fetal ductal constriction following indomethacin use for fetal-surgery

Abstract

The objectives of the study were to determine the prevalence and to identify risk factors associated with constriction of the fetal ductus arteriosus (DA) following perioperative indomethacin use following fetal myelomeningocele (MMC) repair in a single large fetal center. A retrospective chart review study included 100 consecutive fetuses with normal preoperative echocardiography (FE) who underwent fetal MMC repair between December 2011 and December 2018. All patients had FE on postoperative day (POD) # 1 and 2 to detect constriction of the DA. All patients received indomethacin for tocolysis using a standardized protocol for 48 hours. The POD# 2 doses were withheld if ductal constriction was detected on POD# 1. Multivariate regression analysis was carried out to identify the predictors for fetal ductal constriction and to adjust for potential confounders. Data were expressed as median and interquartile range (IQR) or number and percentages. Eighty patients met our study eligibility criteria. The demographic characteristics of the study population are summarized in Table 1. Constriction of the DA was detected in 14 fetuses (17.5%). In 5 fetuses, this was observed on POD# 1, in 7 on POD# 2 and in 2 on both days. Multivariate regression analysis showed that the only independent risk factor for predicting constriction of the DA was maternal body mass index (BMI) < 25 Kg/m2 (p=0.002) (Table 2). All affected fetuses showed resolution of ductal constriction within a median of one day after indomethacin administration was stopped. In one case, constriction was particularly severe with partial reversal after 6 days and complete reversal after 15 days. Perioperative maternal indomethacin therapy following fetal MMC surgery requires careful daily fetal echocardiography due to the high incidence of fetal ductal constriction. The association of fetal DA constriction and low BMI warrants further investigation and suggests that BMI-based dosing of indomethacin may be recommended for perioperative tocolysis in fetal MMC surgery.View Large Image Figure ViewerDownload Hi-res image Download (PPT)