Transplant Suitability of Rejected Human Donor Lungs With Prolonged Cold Ischemia Time in Low-Flow Acellular and High-Flow Cellular Ex Vivo Lung Perfusion Systems

Background. Ex vivo lung perfusion (EVLP) has the potential to increase the number of donor lungs available for lung transplantation (LTx). While the current maximum cold ischemia time (CIT) for donor lungs in clinical LTx is around 8 hours, there are no data regarding the potential use of rejected donor lungs with CIT >8 hours before EVLP. The purpose of this study was to investigate the transplant suitability of lungs with a prolonged CIT in 2 EVLP systems. Methods. Following prolonged CIT of 13.8 hours (range 9.0-19.5 h), 16 rejected human donor lungs were randomly divided and perfused using either low-flow acellular or high-flow cellular EVLP systems (n = 8, each). Transplant suitability was evaluated according to the standard criteria of each EVLP system. Results. The high-flow cellular group was associated with a significantly lower transplant suitability (0% versus 37%, P = 0.027), significantly lower wet-to-dry ratio change (-0.71 +/- 0.62 versus 0.43 +/- 1.01, P = 0.035), and lower pathological score (1.62 +/- 0.61 versus 3.00 +/- 0.61, P = 0.163) than the low-flow acellular group. In both systems, inflammatory cytokines on perfusate (tumor necrosis factor-alpha, interleukin [IL]-1 ss, IL-6, IL-8, and IL-10) increased in a time-dependent manner and were significantly higher than those of controls with CIT <8 hours (P < 0.05). Conclusions. The potential for reconditioning lungs with a CIT >8 hours is diminished compared with that for lungs having a shorter CIT due to severe ischemia reperfusion injury.