ORGAN DONATION AND ALLOCATION II

A. Reid¹, S. Harper², C. Jackson¹, L. Sharples¹, M. Ryan¹, J.A. Bradley³, G.J. Pettigrew^3
1Department Of Surgery, Cambridge University, Cambridge/UNITED KINGDOM, ², Cambridge University, Cambridge/UNITED KINGDOM, ³Department Of Surgery, University of Cambridge, Cambridge/UNITED KINGDOM

Body: Introduction Donation after Cardiac Death (DCD) is an increasingly important source of kidney transplants, but because of concerns of ischaemic injury during the agonal phase (from controlled withdrawal of lifesaving treatment (WLST) until cardiorespiratory arrest), many centres abandon donation if arrest has not occurred within one hour. We report our experience using a minimum 'cut-off' time of four hours. Methods and Results Between 2004 and 2009, 425 potential DCD donors were referred. The majority (56%) could not be pursued either because of medical unsuitability or relative refusal. Of the 173 who underwent WLST, 117 (68%) became donors. 234 kidneys were retrieved, but 31 were not implanted due to either poor perfusion or chronic disease on biopsy. 7 developed acute arterial or venous thrombosis and 6 never functioned. Median 3-month eGFR in the 190 transplanted kidneys was 45.5ml/min/1.73m² which is slightly lower than the contemporaneous DBD kidneys at 3 months 51.7ml/min/1.73m² (p=0.0042). 75% of donors (88/117) arrested within one hour. Lengthening the cut-off time from one to four hours therefore increases donor numbers by 33%, but creates uncertainty as to the viability of kidneys from donors who deteriorate slowly and suffer lengthy instability prior to arrest. To address this, donors were scored according to the presence of five abnormal physiological indices during the agonal phase (acidaemia (frequency 36%), lactic acidosis (38%), and prolonged (>30mins) hypotension (23%), hypoxia (29%) or oliguria (28%)). The impact of each of the agonal-phase indices on graft outcome (development of delayed graft function (DGF) and three-monthly eGFR) was then evaluated by multivariate regression analysis. Included in this analysis were donor characteristics previously associated with poor graft outcomes (age, sex, terminal creatinine, non-trauma death), cold ischaemic time (CIT), warm ischaemic time (WIT) and agonal phase duration (APD). Surprisingly, there was no association between the agonal-phase variables and DGF or eGFR; either when the variables were considered individually or when the overall agonal-phase score was assessed. The only variables that significantly influenced eGFR were age and CIT, with a 10 year increase in donor age and every additional hour of CIT associated with a reduction in eGFR, respectively of 4, and 1 ml/min/1.73m². Paired analysis confirmed that the eGFR was significantly poorer in the kidney of a pair transplanted last, with an average difference in eGFR between first and second kidneys of 6.04 ml/min/1.73m² (p=0.0236). Finally, eGFR was no different between kidneys from donors whose agonal phase was more than one hour and those from donors who arrested within one hour. Conclusions Relatively few (28%) of DCD referrals proceed to kidney retrieval. Our results demonstrate that DCD kidney numbers can be increased by approximately one third and surprisingly, that prolonged time to asystole and development of unfavourable agonal characteristics do not have a detrimental impact on graft function at 3 months.

Disclosure: All authors have declared no conflicts of interest.