Normothermic liver perfusion ex situ: a resuscitation tool for hepatic grafts damaged by warm ischemia

Ex situ perfusion of the liver has been proposed as a preservation tool for organs to be grafted; in this study, we have investigated whether this procedure could help to reverse damage caused by prolonged ischaemia. The liver was explanted from 6 pigs under general anaesthesia. The organs were subject to warm ischaemia (37 degrees C) for 30 min., cooled in situ by portal infusion of Euro Collins, excised and maintained ischaemic at 4 degrees C for 30 min. more. Afterwards, normothermic perfusion was achieved through the portal vein and hepatic artery for 6 hrs. The parameters measured allowed to follow up the hemodynamic, metabolic and structural response of the liver to the experimental procedure. By electron microscopy, generalized hepatocyte damage was observed after ischaemia, but appeared to be reversed in most cells after ex situ perfusion. Wide areas of sinusoidal walls were devoid of endothelial lining; where this was present, however, it was normal in structure. Kupffer and Ito cells had normal structure whenever observed. Four livers were implanted orthotopically into recipient animals, which were monitored for hemodynamic and biochemical parameters during surgery and followed up to one week. Post mortem examination was performed on the animals which died before this end point. Two of them were alive after one week. Two animals died, one for a perforation of the right hepatic vein and the other for massive necrosis of the left lobe with sepsis and hemorrhage. These results indicate that normothermic ex situ perfusion of the liver has the potential to become a valuable tool to reverse ischaemic injury and monitor organ function before grafting.