Abstract
Use of kidneys from extended criteria donors (ECD) and donors after cardiac death (DCD) has increased due to scarcity of standard criteria donor (SCD) kidneys. DCD kidneys due to preprocurement ischemia and ECD kidneys due to marginal quality are likely to suffer from delayed graft function (DGF) and early graft loss. Any prolonged cold ischemia time (CIT) is likely to add to the injury, although this has not been specifically addressed. We examined the relationship between CIT and the function and survival of these kidneys and compared to SCD kidneys using the 2004 UNOS data set. In 2000, 9,469 (87%) kidneys were SCD, 165 (2%) were DCD, and 1,191(11%) were ECD. The donor age were 31 ± 14 years and 34 ± 17 years for SCD and DCD and higher at 60 ± 6 years for ECD kidneys (mean ± SD). CIT were similar: 18.6 ± 8.3 hours, 19.0 ± 8.4 hours, and 18.7 ± 8.3 hours. The HLA mismatches were not different, but the recipient age was higher for ECD (52 ± 13 years) than for DCD (48 ± 13 years) or SCD kidneys (43 ± 14 years) (p < .001 ECD vs the rest). DGF was higher for DCD and ECD kidneys than for SCD kidneys, eg, discharge serum creatinine was higher for DCD (4.7 ± 3.4 mg/dL) and ECD (4.1 ± 3.0 mg/dL) than for SCD kidneys (2.8 ± 2.5 mg/dL) (p < .001 for all interactions). Similarly, requirement for dialysis was highest for the DCD kidney recipients (46% for DCD, 37% for ECD, and 26% for SCD). Despite severe early injury in DCD kidneys, 4-year graft loss was similar between DCD and SCD kidneys ({223}25%) but was higher for ECD kidneys (38%; p < .001 vs the rest). In the Cox hazard analysis, CIT had significantly higher relative risk (RR) for graft failure over 30 hours for all groups combined and for each of the three groups separately. However, the preexisting injury of DCD or ECD kidneys did not add to the RR of cold ischemia on 4-year graft loss. In aggregate, despite early injury, DCD kidneys have similar graft survival as in SCD kidneys, and irrespective of donor type, CIT over 30 hours reduces renal allograft survival across the donor types. Thus, this analysis supports the wider use of DCD kidneys and the need for avoiding prolonged cold ischemia time of kidneys irrespective of donor types.