Letter to the Editor: Can ex-situ normothermic perfusion improve graft survival among donation after circulatory death liver allografts?

Abstract

To the editor, We read with great interest the manuscript by Ibeabuchi et al recently published in Liver Transplantation.1 The authors found that ex-situ normothermic liver perfusion (ENLP) improved graft survival compared to static cold storage among donation after circulatory death (DCD) liver allografts by identifying the United Network of Organ Sharing database. This was consistent with the results of a randomized trial, which confirmed that ENLP was associated with a 50% lower level of graft injury, with these benefits being greatest in the DCD subgroup.2 Besides, considering that ENLP DCDs were performed at 20 (19.8%) of the 101 centers, the authors conducted a subanalysis restricted to the 20 centers to eliminate potential baseline differences in graft outcomes related to center experience, and the results were largely unchanged. Despite this, the results should still be interpreted with caution. The number of ENLP DCDs performed among these 20 centers ranged from 1 to 10 (median: 2; interquartile range: 1–4.5). In only a few cases in each center, it was not clear in what circumstances ENLP was selected, which inevitably led to significant limitations. All the time, the time window for evaluating the feasibility of donor livers is relatively short, and the time for surgery is severely limited. These all lead to the urgency of liver transplantation and sometimes to the fact that part of the liver available for transplantation has to be wasted. The advantages of ENLP are to create a more physiological environment in vitro and maintain the normal physiological function of donor livers, which can provide opportunities for precise evaluation and intervention treatment of donor livers. ENLP intervention allows longer total preservation times, achieves higher organ use rates, and may indeed be a promising option for organ preservation in vitro.3 However, the ENLP process is relatively complex and requires advanced equipment and technological capabilities. Once problems occur in the operation process, it is likely to cause further damage to the liver. Meanwhile, ENLP does not appear to be suitable for split liver transplantation because it may increase the warm ischemia time through additional rewarming steps. Last, whether ENLP is required for the full duration of livers’ preservation or can equally well be applied after a short period of static cold storage when the livers reach the transplant center.