EP25.04: Prevalence of recipients' right ventricular outflow tract abnormalities in Twin–twin transfusion syndrome after fetoscopic laser surgery

Right ventricular outflow tract obstruction (RVOTO) is a severe complication in recipients of twin-twin transfusion syndrome (TTTS). This study investigated the prevalence of RVOTO in TTTS after laser surgery and examined the risk factors for RVOTO. Methods This study evaluated 90 patients who had undergone laser surgery and been followed for 6 months after birth. The diagnosis of RVOTO was made based on postnatal echocardiography. Ultrasound and clinical records, including maternal and neonatal data, were retrieved from our database. Risk factors for developing RVOTO were compared between recipients with and without RVOTO in a statistical analysis. Results Six surviving recipients were diagnosed with RVOTO. Three recipients had developed severe pulmonary stenosis (PS) that required percutaneous transluminal pulmonary valvuloplasty or balloon pulmonary angioplasty(No. 2,4,6 in Table 1). A total of 6.7% of recipients (6/90 cases) had RVOTO, consisting of PS, tricuspid regurgitation (TR), and 3.3% of recipients (3/90 cases) required invasive treatment (Table 1). The characteristic factors did not differ significantly between recipients with and without RVOTO (Table 2). Conclusions This study revealed that 6.7% of recipients with TTTS had PS, and 3.3% required invasive treatment for PS. However, no significant association was revealed between RVOTO development in recipients and fetal ultrasound examination findings. It is difficult to predict RVOTO development in recipients using only preoperative ultrasound and clinical information. No. GA at laser (wks) TTTS stage CTAR(%) pre-laser AREDF of UA AREDF of DV pulsation of UV PS, TR in fetal period PS,TR in neonatal period outcome Postnatal course