OP26.09: Fetal E/e' by dual gate Doppler method in Twin–twin transfusion syndrome and relationship with amniotic fluid brain‐type natriuretic peptide

Abstract

To investigate the utility of E/e' ratio in the identical cardiac cycle by using Dual gate Doppler method (DD method) in the cases with Twin–twin transfusion syndrome (TTTS) for ventricular diastolic function, and relationship between fetal E/e' and amniotic fluid N-terminal-prohormone BNP (NT-proBNP) as a marker of cardiac dysfunction. This is a prospective study involving cases with TTTS, which were performed fetoscopic laser photocoagulation (FLP) from December 2015 to March 2017. To evaluate E/e' in the same heartbeat, DD method was used in all measurements. The ultrasonography was performed within 24 hours before FLP and 4-7 days after the procedure. Reference values acquired from normal 153 singleton fetuses in our previous study were used to compare with the present data. E/e' >10 was considered elevated from reference values. Amniotic fluid samples for analysis of NT-proBNP were obtained at the time of FLP. Amniotic fluid total protein (TP) concentration was used for correction of the level of NT-proBNP. Twenty-eight TTTS cases were included in this study. Preoperative right E/e' in Quintero stage 3 recipient twins was likely elevated than reference values, and significantly higher than stage 1, 2 recipients (p=0.001). In cases with right E/e' >10, amniotic fluid NT-proBNP/TP was elevated (3,475 vs. 518 ng/g, p=0.008), and ductus venosus pulsatility index (DV-PI) was high (1.34 vs. 0.75, p=0.020). Bilateral E/e' in recipients decreased 4-7 days after FLP (p=0.007). As for donor twins, no significant change was seen in bilateral E/e'. The measurement of fetal E/e' using DD method was convenient and stable. E/e' is seemed a useful parameter of fetal cardiac dysfunction in recipient twins, related with amniotic fluid NT-proBNP and DV-PI. Interestingly, bilateral E/e' of recipients indicated significant decrease within 7 days after FLP. These findings might imply FLP improves pathological condition of diastolic dysfunction in recipient twins.