Thrombocytopenia-associated multi-organ failure after Fontan operation successfully treated with plasma exchange: A case report

Introduction: Thrombocytopenia-associated multi-organ failure (TAMOF) is a rare but life-threatening subtype of multiple organ dysfunction syndrome caused by thrombotic microangiopathy and decreased A Disintegrin and Metalloproteinase with a Thrombospondin type 1 motif, member 13 (ADAMTS-13) activity. Although commonly associated with sepsis, TAMOF is rarely reported after cardiac surgery. Case Presentation: We report a 10-year-old girl with right atrial isomerism and complex congenital heart disease who developed TAMOF following extracardiac Fontan surgery. She presented with distributive shock, persistent thrombocytopenia, acute kidney injury requiring continuous renal replacement therapy, transaminitis, and encephalopathy. Laboratory findings demonstrated thrombotic microangiopathy with elevated inflammatory markers. Plasma exchange (PLEX) was initiated based on clinical suspicion and later confirmed by reduced ADAMTS-13 activity. After two PLEX sessions, the patient showed rapid improvement, including platelet recovery, resolution of neurological, hepatic, and renal dysfunction, and successful extubation. Conclusions: Early recognition of TAMOF in post-cardiac surgery patients with unexplained thrombocytopenia and multi-organ dysfunction is critical. Prompt PLEX may result in clinical recovery and improved survival.