OP16.02: Outcome of the pump twin following early intrafetal laser in twin reversed arterial perfusion sequence

To report the perinatal outcome of the pump twin following early ultrasound-guided intrafetal laser of the acardiac twin in the treatment of twin reversed arterial perfusion (TRAP) sequence. International multicentre retrospective study of monochorionic diamniotic (MCDA) twin pregnancies complicated with TRAP sequence and treated with ultrasound-guided intrafetal laser coagulation of the acardiac twin before 18 weeks of gestation, from January 2012 to February 2024. Presentation, surgical events and perinatal outcomes were analysed. A total of 21 MCDA twin pregnancies complicated with TRAP sequence were treated with ultrasound-guided intrafetal laser at a median gestational age of 15.7 weeks (IQR 15-16.9). None of the pump twins presented hydrops at the time of laser but 4.8% (1/21) presented pericardial effusion and 4.8% (1/21) presented tricuspid regurgitation. Blood flow in the ductus venosus was reported in 18 pump twins and 7 of them (39%) presented absent or reversed a wave. The median surgical time was 15 minutes (IQR 4-45). In 9.5% of the cases (2/21) a reintervention was needed due to restoration of blood flow in the acardiac twin. Fetal demise of the pump twin was seen in 38% of the cases (8/21) with 25% of them (2/8) detected within 24 hrs, 62.5% (5/8) within 7 days, and 37.5% (3/8) after 20 weeks. There were no cases of premature preterm rupture of membranes and the median gestational age at birth was 38.3 weeks (IQR 37.7-40.) with only 1 case delivered preterm at 35.1 weeks. There were no neonatal deaths. The overall survival of the pump twin was 62% (13/21). Intrafetal laser before 18 weeks in the treatment of TRAP sequence has a 38% mortality of the pump twin with almost two-thirds of them being fetal demises within the first week after intrafetal laser.