Improvements in kidney transplantation from donors after cardiac death

Impact of Donor Age on Clinical Outcomes of Primary Single Kidney Transplantation From Maastricht Category-III Donors After Circulatory Death

BACKGROUND

Standard-criteria donation after circulatory death (DCD) kidney transplants (KTx) have higher primary nonfunction, delayed graft function (DGF), and rejection rates than age-matched donation after brain death (DBD) but similar graft survival. Data on expanded-criteria DCD are conflicting and many centers remain concerned regarding their use.

METHODS

In this single-center observational study with 5-year follow-up, we analyzed data from 112 primary DCD Maastricht category-III single KTx receiving similar organ preservation and maintenance immunosuppression. Patients were sorted as young DCD (donor <60 years, 72 recipients) or old DCD (donor ≥60 years, 40 recipients). Old DCD outcomes were compared with young DCD and to a DBD control group (old DBD, donor ≥60 years, 40 recipients).

RESULTS

After 5 years, old DCD showed lower patient survival (66% vs 85%; P = 0.014), death-censored graft survival (63% vs 83%; P = 0.001), and Modification of Diet in Renal Disease estimated glomerular filtration rate (34, 27.0-42.0 mL/min per 1.73 m2 vs 45.0, 33.0-58.0 mL/min per 1.73 m2; P = 0.021) than young DCD with higher DGF (70% vs 47.2%; P = 0.029) and graft thrombosis (12.5% vs 1.4%; P = 0.021). Comparison between old DCD and old DBD showed similar 5-year patient survival (66% vs 67%; P = 0.394) and death-censored graft survival (63% vs 69%; P = 0.518) but higher DGF (70% vs 37.5%; P = 0.007) and lower estimated glomerular filtration rate (34, 27.0-42.0 mL/min per 1.73 m2 vs 41, 40.0-42.0 mL/min per 1.73 m2; P = 0.029). Multivariate Cox regression analysis showed that donor 60 years or older (hazard ratio, 3.135; 95% confidence interval, 1.716-5.729; P < 0.001) and induction with anti-IL2-receptor-α monoclonal antibody (hazard ratio, 0.503; 95% confidence interval, 0.269-0.940, P = 0.031 in favor of induction with rabbit antithymocyte globulin) are independent predictors of transplant loss.

CONCLUSIONS

Overall, single KTx from DCD Maastricht category-III donors 60 years or older have inferior outcomes than KTx from donors younger than 60 years. Comparison with age-matched DBD showed similar patient and graft survivals. However, the discrepancy in graft function between DCD and DBD deserves further investigation.

Fifteen-Year Analysis of Deceased Kidney Donation: A Single Transplant Center Experience in a Region of Northern Italy

Background

The rising number of patients on waiting lists for kidney transplant and the shortage of available organs has intensified efforts to increase the number of potential donors.

Material/Methods

This study investigated changes in clinical parameters among potential deceased donors in the 15-year period between 1999 and 2013 and their impact on transplantation procedure and outcomes. A total of 1634 potential deceased donors were examined and divided into 2 groups: 707 of them identified from 1999 to 2005 (Group A), and 927 from 2006 to 2013 (Group B).

Results

The comparison between the potential donors in Group A vs. Group B revealed an increase over time in donor age (54.6±17.2 vs. 58.8±16.3, p<0.001), a reduction in the percentage of standard donors (52.3% vs. 39.8%, p<0.001), a broader utilization of organs from expanded criteria donors, and a greater number of comorbidities, particularly cardiovascular disease and dyslipidemia. However, renal function parameters and the bioptic scores did not change significantly over the years.

Conclusions

These results suggest the usefulness of strategies to increase the number of potential donors suitable for organ donation, especially among elderly and marginal donors.

Transplantation of kidneys from uncontrolled donation after circulatory determination of death: comparison with brain death donors with or without extended criteria and impact of normothermic regional perfusion

The aim of this study was to compare the outcomes of kidney transplants from uncontrolled DCD (uDCD) with kidney transplants from extended (ECD) and standard criteria donors (SCD). In this multicenter study, we included recipients from uDCD (n = 50), and from ECD (n = 57) and SCD (n = 102) who could be eligible for a uDCD program. We compared patient and graft survival, and kidney function between groups. To address the impact of preservation procedures in uDCD, we compared in situ cold perfusion (ICP) with normothermic regional perfusion (NRP). Patient and graft survival rates were similar between the uDCD and ECD groups, but were lower than the SCD group (P < 0.01). Although delayed graft function (DGF) was more frequent in the uDCD group (66%) than in the ECD (40%) and SCD (27%) groups (P = 0.08 and P < 0.001), graft function was comparable between the uDCD and ECD groups at 3 months onwards post-transplantation. The use of NRP in the uDCD group (n = 19) was associated with a lower risk of DGF, and with a better graft function at 2 years post-transplantation, compared to ICP-uDCD (n = 31) and ECD. In conclusion, the use of uDCD kidneys was associated with post-transplantation results comparable to those of ECD kidneys. NRP preservation may improve the results of uDCD transplantation.

Donor Hemodynamics as a Predictor of Outcomes After Kidney Transplantation From Donors After Cardiac Death

Donation after cardiac death is an important source of transplantable organs, but evidence suggests donor warm ischemia contributes to inferior outcomes. Attempts to predict recipient outcome using donor hemodynamic measurements have not yielded statistically significant results. We evaluated novel measures of donor hemodynamics as predictors of delayed graft function and graft failure in a cohort of 1050 kidneys from 566 donors. Hemodynamics were described using regression line slopes, areas under the curve, and time beyond thresholds for systolic blood pressure, oxygen saturation, and shock index (heart rate divided by systolic blood pressure). A logistic generalized estimation equation model showed that area under the curve for systolic blood pressure was predictive of delayed graft function (above median: odds ratio 1.42, 95% confidence interval [CI] 1.06-1.90). Multivariable Cox regression demonstrated that slope of oxygen saturation during the first 10 minutes after extubation was associated with graft failure (below median: hazard ratio 1.30, 95% CI 1.03-1.64), with 5-year graft survival of 70.0% (95%CI 64.5%-74.8%) for donors above the median versus 61.4% (95%CI 55.5%-66.7%) for those below the median. Among older donors, increased shock index slope was associated with increased hazard of graft failure. Validation of these findings is necessary to determine the utility of characterizing donor warm ischemia to predict recipient outcome.

Recommendations for donation after circulatory death kidney transplantation in Europe

Donation after circulatory death (DCD) donors provides an invaluable source for kidneys for transplantation. Over the last decade, we have observed a substantial increase in the number of DCD kidneys, particularly within Europe. We provide an overview of risk factors associated with DCD kidney function and survival and formulate recommendations from the sixth international conference on organ donation in Paris, for best-practice guidelines. A systematic review of the literature was performed using Ovid Medline, Embase and Cochrane databases. Topics are discussed, including donor selection, organ procurement, organ preservation, recipient selection and transplant management.

Kidney donation after circulatory death (DCD): state of the art

The use of kidneys from controlled donation after circulatory death (DCD) donors has the potential to markedly increase kidney transplants performed. However, this potential is not being realized because of concerns that DCD kidneys are inferior to those from donation after brain-death (DBD) donors. The United Kingdom has developed a large and successful controlled DCD kidney transplant program that has allowed for a substantial increase in kidney transplant numbers. Here we describe recent trends in DCD kidney donor activity in the United Kingdom, outline aspects of the donation process, and describe donor selection and allocation of DCD kidneys. Previous UK Transplant Registry analyses have shown that while DCD kidneys are more susceptible to cold ischemic injury and have a higher incidence of delayed graft function, short- and medium-term transplant outcomes are similar in recipients of kidneys from DCD and DBD donors. We present an updated, extended UK registry analysis showing that longer-term transplant outcomes in DCD donor kidneys are also similar to those for DBD donor kidneys, and that transplant outcomes for kidneys from expanded-criteria DCD donors are no less favorable than for expanded-criteria DBD donors. Accordingly, the selection criteria for use of kidneys from DCD donors should be the same as those used for DBD donors. The UK experience suggests that wider international development of DCD kidney transplantation programs will help address the global shortage of deceased donor kidneys for transplantation.

Kidney donation after circulatory death (DCD): state of the art

Ischemia–reperfusion (IR) injury to the kidney occurs in a range of clinically important scenarios including hypotension, sepsis and in surgical procedures such as cardiac bypass surgery and kidney transplantation, leading to acute kidney injury (AKI). Mitochondrial oxidative damage is a significant contributor to the early phases of IR injury and may initiate a damaging inflammatory response. Here we assessed whether the mitochondria targeted antioxidant MitoQ could decrease oxidative damage during IR injury and thereby protect kidney function. To do this we exposed kidneys in mice to in vivo ischemia by bilaterally occluding the renal vessels followed by reperfusion for up to 24 h. This caused renal dysfunction, measured by decreased creatinine clearance, and increased markers of oxidative damage. Administering MitoQ to the mice intravenously 15 min prior to ischemia protected the kidney from damage and dysfunction. These data indicate that mitochondrial oxidative damage contributes to kidney IR injury and that mitochondria targeted antioxidants such as MitoQ are potential therapies for renal dysfunction due to IR injury.