Iron Deficiency in Adults with Complex and/or Cyanotic Congenital Heart Disease—How to Diagnose and Whom to Treat? - von Scheidt, F.; Freilinger, S.; Scharffetter, M.; Uhlig, C.; Wolf, Z.; Sander, M.; Ewert, P.; Nagdyman, N.; Kaemmerer, H.; Holdenrieder, S. (The Thoracic and Cardiovascular Surgeon, 2025)