Changes in Fetal Doppler Parameters Following Ablation of Placental Anastomoses in Twin-Twin Transfusion Syndrome [34D

Abstract

INTRODUCTION: Unequal placental sharing and unbalanced blood volume distribution contribute to TTTS in monochorionic pregnancies. This study describes changes in fetal Dopplers following laser photocoagulation of placental anastomoses. METHODS: 230 women undergoing surgery for TTTS between 01/2012 and 05/2018 were included. Laser surgery was performed for Quintero stages II and greater, or stage I with symptomatic polyhydramnios, short cervix, or preterm labor. Pre and post-laser differences in impedance to blood flow in the umbilical artery (UA) and ductus venosus (DV) using pulsatility index (PI), as well as the middle cerebral artery peak systolic velocity [MCA PSV, as multiple of the median (MoM)] were calculated. RESULTS: TTTS Quintero stages I, II, III, and IV were present in 10%, 31.3%, 50.9% and 7.8% of cases. Median interval between scans before and after surgery was 2 days [interquartile range (IQR) 1-3 days]. Among donors, there was a significant reduction in UA PI [median prior: 1.313, IQR: 1.12-1.48 vs. median post PI: 1.186, IQR: 1.00-1.33, p<0.001). A similar trend among recipients did not reach significance. Among recipients, a significant elevation in MCA PSV was noted following surgery (median pre: 0.993 MoM, IQR: 0.82 to 1.12 vs. median post PSV: 1.077 MoM, IQR: 0.86-1.26; p=0.003. No significant differences were noted in DV PI changes in either donor or recipient twins. CONCLUSION: Reductions in the resistance to donor twin umbilical artery blood flow and improvements in recipient middle cerebral artery peak systolic velocity may represent early sonographic signs of TTTS resolution following laser surgery.