199: Intertwin growth discordance after laser surgery for twin-twin transfusion syndrome: Risk factors and outcomes

Abstract

Secondary severe fetal growth restriction (FGR, fetal growth discordance of ≥ 25% in monochorionic twins), is associated with increased perinatal mortality and morbidity in twin-twin transfusion syndrome (TTTS). In this study we identified risk factors for worsening or improved growth discordance in patients undergoing fetoscopic laser surgery (FLS) for TTTS. Prospective cohort of monochorionic diamniotic twin patients undergoing FLS for TTTS (N= 311) at a single fetal center from 2012-2017. Exclusion criteria were triplet gestation and intrauterine demise. Overall growth discordance at pre-op and at delivery was compared. Three groups were identified: Group 1- worsening discordance (+/- pre-op FGR and + FGR at delivery), Group 2- improved discordance (+ pre-op FGR and - FGR at delivery), and Group 3- stable without FGR. Comparative analysis was performed between the two most divergent outcomes: Group 1 vs. Group 2. 242 patients met inclusion criteria: Median fetal growth discordance in the entire cohort before FLS was 22% (IQR 13% - 31%) vs. 11% at birth (IQR 4% - 23%); p<0.001. Group 1 had 57 patients, Group 2 had 65 patients and Group 3 had 120 patients. The significant and most relevant variables between groups are presented in Table 1. Patients in Group 1 were more likely to have an earlier delivery and fewer neonatal survivors. Risk factors for Group 1 in comparison to Group 2 are presented in Figure 1 by stepwise logistic regression. These include, recipient MVP, donor fetus velamentous cord insertion and presence of A-A anastomosis. On average, patients who undergo FLS for TTTS show improvement in fetal weight discordance at birth. However, a sub-group of patients has worsening discordance and poor neonatal outcomes. Placental share and vascular anatomy appear to drive post-procedure fetal growth patterns. These risk factors should be considered in pre- operative counseling and planning for FLS and long term outcomes for these neonates should be evaluated.View Large Image Figure ViewerDownload Hi-res image Download (PPT)