Hypothermic oxygenated perfusion (HOPE) in human and rat DCD livers. (A) An example of hypothermic oxygenated perfusion (HOPE) of an extended DCD liver graft prior to transplantation. (B) To confirm a complete perfusion with highly-oxygenated perfusate in the cold during HOPE, Fluorescein was added to the perfusate. Both human and rat livers showed a rapid complete perfusion in the cold, despite a low perfusion pressure of 3 mmHg or less. Notably, the entire biliary tree, including the distal tip where the anastomosis is performed with the recipient bile duct, appears also completely stained, which confirms that the perfusate and more importantly the oxygen has reached all liver cells including cholangiocytes. The approval numbers were KEK ZH 2012-1 (January 2012) and KEK ZH 2017-00309 (July 2017), both approved by the Cantonal Ethic Commission in Zurich.