Prognosis for ECD kidneys transplanted since 1996 is similar to that of live donor organ recipients
The survival of expanded criteria donor (ECD) kidneys has improved markedly since 1996, according to a recent study published in Clinical Transplantation (2008; published online ahead of print).
Robert P. Carroll, MD, and colleagues, at the Royal Melbourne Hospital in Australia, reviewed data on 635 patients who underwent renal transplantation between January 1989 and March 2004. They found that patients transplanted after 1996 were 49% less likely to experience graft loss compared to patients transplanted pre-1996. This improvement in graft survival occurred despite the age of donors increasing during the study period, from 32 to 48 years for deceased donors, and from 38 to 44 years in living donors.
The study focused on the outcome of ECD kidneys. The United Network for Organ Sharing (UNOS) defines an ECD as a donor older than 60 years or aged 50-59 years with two of the following: history of hypertension, cerebrovascular death, or creatinine level above 1.5 g/dL.
There were 55 deceased donor kidneys that met these criteria. Eighteen were transplanted before 1996 and 37 were transplanted in 1996 or later. All of these ECD kidneys were transplanted as single organs and no dual transplantation of ECD kidneys was performed at this center. ECD kidneys transplanted prior to 1996 were 3.5 times as likely to fail compared with live donor kidneys. After this time ECD kidneys had a prognosis similar to that of live donor kidneys.
The study showed the importance of minimizing delayed graft function. Delayed graft function (DGF) was defined as a failure of serum creatinine to fall by 10% and the need for dialysis within 72 hours of transplantation. The five-year probability of graft survival in patients who experienced DGF was 67% compared with 86% of patients without DGF. The prevalence of DGF was low at 16.7% and may reflect the short median ischemic time of 13 hours in this study.
The Melbourne-based group noted that the improvement in graft survival was not explained by any of the measured donor or recipient factors they studied, but suggested that short-ischemic times “may allow improved graft survival from older donors by reducing the risk and long-term impact of DGF.”
Changes in immunosuppression over the study period were also listed as potential factors impacting on graft survival. After 1996, mycophenolate was introduced and calcineurin inhibitor doses fell, the group noted.