The Impact of Combined Warm Ischemia Time on Development of Acute Kidney Injury in Donation after Circulatory Death Liver Transplantation: Stay Within the Golden Hour

Background Acute kidney injury (AKI) is a common complication after liver transplantation and more frequently observed when high-risk grafts, such as donation after circulatory death (DCD) grafts are used. Our aim was to investigate the impact of the ischemia periods on development of AKI in DCD liver transplantation. Methods We performed a 2-center retrospective study with 368 DCD graft-recipients. Donor warm ischemia time (DWIT) was divided into agonal phase (withdrawal of life support-cardiac arrest) and asystolic phase (cardiac arrest-start cold perfusion). We introduced a new period of warm ischemia: the combined warm ischemia time (combined WIT), which was defined as the sum of DWIT and recipient WIT. Results AKI was observed in 65% of the recipients and severe AKI in 41% (KDIGO stage 2/3). The length of combined WIT increased significantly with AKI severity: 61 minutes in recipients without AKI up to 69 minutes in recipients with the most severe form of AKI (P < 0.001). On multivariable analysis, increasing duration of the combined WIT was associated with an increased risk of developing severe AKI (odds ratio, 1.032 per every extra minute; 95% confidence interval, 1.014-1.051; P < 0.001). No relation was observed between length of cold ischemia time and severe AKI. Conclusions Combined WIT is a newly defined period of warm ischemia in DCD liver transplantation. Length of combined WIT is associated with severity of postoperative AKI and should ideally not exceed 60 minutes