Platypnea–Orthodeoxia syndrome following stent implantation into the Fontan tunnel

Fontan conduit stenosis can impair haemodynamics, necessitating stent implantation. We present a 16-year-old patient who developed platypnea-orthodeoxia syndrome due to a post-stenting baffle leak. Despite initial diagnostic challenges, a second catheterisation confirmed and successfully sealed the defect with a covered stent. This case highlights the need for close monitoring and prompt intervention to manage complications in Fontan patients.