Donation after cardiac death: dynamic graft reconditioning during or after ischemic preservation?

The benefit of gaseous oxygenation during storage of liver grafts from donors after cardiac death should be investigated as applied either during the whole period of preservation or only for the last 2 h prior to reperfusion. Rat livers were explanted 30 min after cardiac arrest of the donor and cold-stored (CS) for 20 h. Some grafts were subjected to venous systemic oxygen persufflation (VSOP) either for 20 h or for only 2 h subsequent to 18 h of CS. Viability of the livers was assessed thereafter by warm reperfusion in vitro. Twenty hours VSOP and 18 h CS + 2 h VSOP prevented mitochondrial protein breakdown of mitochondrial heat shock protein 70 and promoted a significant and approximately twofold increase in hepatic oxygen consumption, bile production, and energetic recovery upon warm reperfusion. No differences were seen whether VSOP was performed for 20 h or for only 2 h prior to reperfusion. Both techniques significantly abrogated parenchymal enzyme loss (alanine aminotransferase, aspartate aminotransferase) upon reperfusion compared with simple 20 h CS. An increase in perfusate levels of the mitochondrial enzyme glutamate dehydrogenase was observed only in the 20 h VSOP group. In conclusion, viability of donation after cardiac death liver grafts can still be augmented, similarly to continuous aerobic storage, by only endischemic reconditioning, both protocols preventing initial mitochondrial dysfunction and subsequent tissue injury.