Takayuki Oyanagi, MD, is an Assistant Professor in the Department of Pediatrics at Keio University School of Medicine, Tokyo, Japan. He is a pediatric cardiologist specializing in congenital heart disease and advanced catheter-based interventions. His clinical and research focus centers on Fontan circulation, protein-losing enteropathy, and lymphatic interventions, as well as transcatheter pulmonary valve implantation. Dr. Oyanagi leads clinical and research initiatives in Japan aimed at improving outcomes in patients with Fontan-associated complications. He is actively engaged in national and international collaborative research, contributing to the development of contemporary interventional strategies for complex congenital heart disease.