Impact of rewarming preservation by continuous machine perfusion: improved post-transplant recovery in pigs.

Background: Utilization of grafts from donors after cardiac death (DCD) greatly expands the organ pool. However, implementation of such a strategy requires the development of novel preservation methods to achieve recovery from changes owing to warm ischemia.

Methods: To assess potential methods, porcine livers harvested after 60 minutes of warm ischemic time (WIT) were perfused and preserved under the following conditions: Group 1 (n = 3), 2-hour simple cold storage and 2-hour machine perfusion (MP) at 8°C; group 2 (n = 3), 2 hours at 25°C and MP at 25°C and group 3 (n = 3), 2-hour simple cold storage and gradual rewarming to 25°C by MP. The preserved liver grafts were transplanted orthotopically into recipients.

Results: The aspartate aminotransferase (AST), lactate dehydrogenase (LDH), and hyaluronic acid (HA) levels in recipient blood at 2 hours after reperfusion were significantly lower among group 3: AST, 789 ± 258.8, 1203 ± 217.0, and 421 ± 55.8 IU/L; LDH, 1417 ± 671.2, 2132 ± 483.9, and 634 ± 263.9 IU/L; and HA, 1660 ± 556.5, 1463 ± 332.3, and 575 ± 239.0 ng/mL for groups 1, 2 and 3, respectively. Histologically, necrosis and swelling of hepatocytes were less severe among group 3 than groups 1 and 2. Group 3 animals showed better vital responses and started spontaneous breathing within 2 hours after reperfusion; 1 recipient survived for >24 hours, although all animals in groups 1 and 2 died within 2 to 3 hours after reperfusion.

Conclusions: Rewarming by MP preservation may facilitate recovery and resuscitation of DCD liver grafts.