Machine perfusion following static cold storage preservation in kidney transplantation: donor-matched pair analysis of the prognostic impact of longer pump time

The impact of machine perfusion (MP) time on kidney transplant outcome is mixed in previous studies using multivariable analyses. In an analysis of 66 pairs of donor-matched adult, first transplant recipients (N = 132) with identical donor characteristics except for pump time, tests of association of shorter versus longer pump time (first versus second kidney removed) by delayed graft function(DGF), slow graft function(SGF), and biopsy proven acute rejection (BPAR) were performed using McNemar's test. Freedom-from-BPAR, graft and patient survival, and renal function were also compared. Mean +/- SD pump times for paired recipients with first and second kidneys were 22.7 +/- 7.3 h and 31.2 +/- 7.9 h, respectively (mean difference: 8.5 +/- 4.5 h, P < .000001). There was no significant impact of pump time on DGF or SGF, with discordant pairs favoring less SGF with longer pump time (N.S.). The incidence of BPAR during the first 12 months post-transplant yielded a borderline difference favoring longer pump time (P = .09), and freedom-from-BPAR during the first 12 months was significantly more favorable for longer pump times (95% vs. 84%, P = 0.04). No differences were observed in graft and patient survival, and renal function. While offering significantly favorable protection from BPAR, this analysis of donor-matched recipient pairs corroborates longer MP (pump) times having no unfavorable effect on other clinical outcomes.