Characterization of the withdrawal phase in a porcine donation after the cardiac death model.

Transplantation of donation after cardiac death (DCD) livers has higher rates of organ failure and complications, specifically ischemic biliary injuries. Reported large animal DCD models all employ active means to halt circulation, contrary to human DCD protocol. We report a DCD porcine model in which the animal passively progresses to cardiac death, thereby more closely mimicking human DCD scenario. Sixteen Yorkshire pigs (10 females, 6 males, 30-45 kg) had a mean time of 26:19 min ± 14:14 from withdrawal of ventilatory support (WVS) to circulatory arrest and 44:38 min ± 16:37 from WVS to electrical standstill. Cessation of hepatic flow (HF) occurred well before electrical standstill (22:15 min ± 10:09), previously not described in human or animal DCD. Histologically comparing livers from our DCD model demonstrated a dramatic increase in hepatocyte vacuolization, disorganization of endoplasmic reticulum, formation of mitochondrial inclusions and apoptosis compared with control specimens. Subtle changes were also evident in biliary epithelial cells (BEC). This results in severe cellular changes before reperfusion. Early histologic evidence suggests that there is severe hepatocyte and biliary cell disruption in our DCD model. Further research using this model may provide a deeper understanding of the pathophysiology of the DCD liver.
(©2011 The Authors Journal compilation©2011 The American Society of Transplantation and the American Society of Transplant Surgeons.)