Prevalence of Right Ventricular Outflow Tract Abnormalities among Recipients in Twin–twin Transfusion Syndrome after Fetoscopic Laser Surgery in 90 Consecutive Cases

Right ventricular outflow tract obstruction (RVOTO) is a severe complication in recipients in twin–twin transfusion syndrome (TTTS). This study investigated the prevalence of RVOTO in TTTS after laser surgery and examined the risk factors for RVOTO. This retrospective 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 findings. 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. 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. A total of 6.7% of recipients (6/90) had RVOTO, consisting of PS and tricuspid regurgitation (TR), and 3.3% of recipients (3/90) required invasive treatment. The characteristic factors did not differ significantly between recipients with and without RVOTO. 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 noted between RVOTO development in recipients and maternal clinical data and fetal ultrasound examination findings. It is difficult to predict RVOTO development in recipients using only preoperative ultrasound and clinical information.