Outcomes of Kidney Transplants from Donation after Cardiac Death Donors Aged 70 Years or Older

Abstract

Introduction: The ongoing expansion of the donation after cardiac death (DCD) donor pool raises questions as to the suitability of using kidneys from very old donors. Double kidney transplantation (DKT) may enable utilisation of a proportion of these kidneys that would otherwise have been discarded. Here we report a single-centre experience of DCD kidney transplants from donors aged 70 years and older, comparing outcomes of single kidney transplants (SKT) and DKT. Methods: Outcomes were assessed for SKT and DKT from DCD donors aged 70 years old between 1 January 2009 and 31 August 2011, with follow-up ceasing on 31 December 2011. The decision to implant a double or single kidney was based on donor and recipient characteristics, macroscopic appearance, and pre-implantation histological score (Remuzzi G et al, NEJM 2006). Estimated GFR (eGFR, mL/min/1.73 m2) was calculated using the 4-variable MDRD equation; delayed graft function (DGF) was defined as the need for dialysis within a week post-transplantation. Continuous variables were described using median (range). Results: Forty-three kidneys were implanted (27 SKT and 8 DKT), with a median follow-up of 13 months. Donor ages were similar in both groups (SKT 73 (70-78) years vs DKT 74.5 (70-79) years; p=0.20). Although median donor terminal creatinine was lower in the SKT group, it did not reach significance (66 (41-88) μmol/L vs 81 (40-235) μmol/L; p=0.07); likewise, there was no difference in donor terminal eGFR (SKT 90 (62-111) mL/min/1.73m2 vs DKT 74 (25-143) mL/min/1.73m2; p=0.25). As expected, kidneys subsequently used as DKT had significantly higher pre-implantation biopsy scores (DKT 5 (3-6) vs SKT 3 (2-6); p< 0.01). Recipients were generally elderly, but median ages were similar between the two groups (SKT 65 (48-75) years vs DKT 64 (57-70) years; p=0.37), as were the cold ischaemic times (SKT 13h18m (9h59m-20h57m) vs DKT 15h40m (11h45m-23h45m); p=0.14). DGF was more frequent in the SKT GROUP, however this did not reach significance (66% (n = 18) for SKT vs 37.5% (n = 3) for DKT, p = 0.15). Graft function (eGFR) was better in recipients of DKT, though this did not reach significance at either one month (SKT 36.7 (19.3-63) mL/min/1.73m2 vs DKT 43.3 (26.5-67.7) mL/min/1.73m2; p=0.46) or 6 months (SKT 34.5 (26.8-58.9) vs DKT 50.8 (28.3-72.7); p=0.26). There were 2 primary non functions and 3 deaths in the SKT group (heart failure, sepsis, invasive aspergillosis), but none of either in the DKT group. Actuarial one-year graft and patient survivals were 92.6% and 88.6% SKT vs 100% and 100% DKT (p=0.44, p=0.37, respectively). Discussion: These early results demonstrate that the DCD donor pool can be expanded through careful selection of donors and recipients. Recipients of DKT from elderly DCD donors had similar outcomes to those receiving SKT, implying that our selection algorithms are adequate. Utilisation of organs from this source is an acceptable strategy to reduce the growing number of older patients waiting for renal transplantation.