TAPS TRIAL: FETOSCOPIC LASER SURGERY VS. STANDARD CARE FOR TWIN ANEMIA-POLYCYTHEMIA SEQUENCE — AN OPEN LABEL RANDOMIZED CONTROLLED TRIAL

INTRODUCTION: Monochorionic twins share a single placenta and are connected to each other through inter-twin vascular anastomoses, allowing the blood to transfer bidirectionally between the two fetuses. Unbalanced net inter-twin blood transfusion can lead to twin anemia-polycythemia sequence (TAPS). TAPS is a newly described form of chronic and slow inter-twin blood transfusion characterized by large inter-twin haemoglobin differences without signs of amniotic fluid discordances. TAPS can occur spontaneously or after laser surgery for twin-to-twin transfusion syndrome. Management options include fetoscopic laser surgery of the vascular equator at the placental surface, intra-uterine blood transfusion with or without partial exchange transfusion, selective feticide, delivery and expectant management. The best treatment option for TAPS is not clear and preliminary data are based on case reports and small cohort studies. DESIGN: We propose to conduct a multi-center open-label randomized controlled trial to assess if fetoscopic laser surgery improves the outcome of TAPS compared to standard care. We will randomly assign 140 monochorionic twin pregnancies diagnosed with TAPS between 20–28 weeks of gestation to the fetoscopic laser surgery group or the standard care group, using a web-based application with a computer-generated list with random permuted blocks, stratified by gestational age at inclusion (20–24 weeks vs. 25–28 weeks) and TAPS type (spontaneous vs. post-laser TAPS). The inclusion period will be 2.5–3 years. OUTCOME: Primary outcome will be a composite of perinatal mortality and severe neonatal morbidity; secondary outcomes include hematological complications, parental anxiety and long-term neurodevelopmental outcome at the corrected age of 2 years.