Expanded criteria donors for kidney transplantation

Machine perfusion versus cold storage for the preservation of kidneys donated after cardiac death: a multicenter, randomized, controlled trial

OBJECTIVE

Hypothermic machine perfusion may improve outcome after transplantation of kidneys donated after cardiac death (DCD), but no sufficiently powered prospective studies have been reported. Because organ shortage has led to an increased use of DCD kidneys, we aimed to compare hypothermic machine perfusion with the current standard of static cold storage preservation.

METHODS

Eighty-two kidney pairs from consecutive, controlled DCD donors 16 years or older were included in this randomized controlled trial in Eurotransplant. One kidney was randomly assigned to machine perfusion and the contralateral kidney to static cold storage according to computer-generated lists created by the permuted block method. Kidneys were allocated according to standard rules, with concealment of the preservation method. Primary endpoint was delayed graft function (DGF), defined as dialysis requirement in the first week after transplantation. All 164 recipients were followed until 1 year after transplantation.

RESULTS

Machine perfusion reduced the incidence of DGF from 69.5% to 53.7% (adjusted odds ratio: 0.43; 95% confidence interval 0.20-0.89; P = 0.025). DGF was 4 days shorter in recipients of machine-perfused kidneys (P = 0.082). Machine-perfused kidneys had a higher creatinine clearance up to 1 month after transplantation (P = 0.027). One-year graft and patient survival was similar in both groups (93.9% vs 95.1%).

CONCLUSIONS

Hypothermic machine perfusion was associated with a reduced risk of DGF and better early graft function up to 1 month after transplantation. Routine preservation of DCD kidneys by hypothermic machine perfusion is therefore advisable.

Assessment of deceased donor kidneys using a donor scoring system

PURPOSE

Marginal grafts should be used more actively in Asian countries where deceased donor transplantation is unpopular. We modified a quantitative donor scoring system proposed by Nyberg and his colleagues and developed a donor scoring system in order to assess the quality of deceased donor grafts and their prognostic value as an initial effort to promote usage of marginal donors.

MATERIALS AND METHODS

We retrospectively evaluated 337 patients.

RESULTS

A scoring system was derived from six donor variables [age, 0-25; renal function, 0-4; history of hypertension, 0-4; Human Leukocyte Antigen (HLA) mismatch, 0-3; body weight, 0- 1; cause of death, 0-3 points]. Donor grafts were stratified by scores: grade A, 0-10; grade B, 11-20; grade C, 21-30; and grade D, 31-40 points. Donor grades significantly correlated with estimated glomerular filtration rate (eGFR) at 6 months (A, 64.0 mL/min/1.73 m(2); B, 57.0 mL/min/1.73 m(2); C, 46.8 mL/min/1.73 m(2); p < 0.001). The five-year graft survival rate was also lower in grade C than grade A (74% vs. 93%, p = 0.002). Donors in grade C and D were regarded as marginal donors. The proportion of marginal donors was much lower in Korea, compared with data from the United Network for Organ Sharing (15.2% vs. 29%).

CONCLUSION

Considering the scarcity of deceased donor kidneys and the relatively better graft outcome with lower grade-donors in Korea, it is worth increasing the usage of marginal grafts.

Application and validation of Cox regression models in a single-center series of double kidney transplantation

A useful approach to reduce the number of discarded marginal kidneys and to increase the nephron mass is double kidney transplantation (DKT). In this study, we retrospectively evaluated the potential predictors for patient and graft survival in a single-center series of 59 DKT procedures performed between April 21, 1999, and September 21, 2008. The kidney recipients of mean age 63.27 +/- 5.17 years included 16 women (27%) and 43 men (73%). The donors of mean age 69.54 +/- 7.48 years included 32 women (54%) and 27 men (46%). The mean posttransplant dialysis time was 2.37 +/- 3.61 days. The mean hospitalization was 20.12 +/- 13.65 days. Average serum creatinine (SCr) at discharge was 1.5 +/- 0.59 mg/dL. In view of the limited numbers of recipient deaths (n = 4) and graft losses (n = 8) that occurred in our series, the proportional hazards assumption for each Cox regression model with P < .05 was tested by using correlation coefficients between transformed survival times and scaled Schoenfeld residuals, and checked with smoothed plots of Schoenfeld residuals. For patient survival, the variables that reached statistical significance were donor SCr (P = .007), donor creatinine cleararance (P = .023), and recipient age (P = .047). Each significant model passed the Schoenfeld test. By entering these variables into a multivariate Cox model for patient survival, no further significance was observed. In the univariate Cox models performed for graft survival, statistical significance was noted for donor SCr (P = .027), SCr 3 months post-DKT (P = .043), and SCr 6 months post-DKT (P = .017). All significant univariate models for graft survival passed the Schoenfeld test. A final multivariate model retained SCr at 6 months (beta = 1.746, P = .042) and donor SCr (beta = .767, P = .090). In our analysis, SCr at 6 months seemed to emerge from both univariate and multivariate Cox models as a potential predictor of graft survival among DKT. Multicenter studies with larger recipient populations and more graft losses should be performed to confirm our findings.

Renal transplantation in old recipients from expanded criteria donors selected by kidney biopsy

BACKGROUND

In Spain, the number of ideal kidney transplant donors has fallen, with at the same time an increase in the number of older recipients on the waiting list.

AIM

To analyze the results of expanded criteria cadaveric donor kidney transplants into older recipients using grafts selected by kidney biopsy.

PATIENTS AND METHODS

We studied 360 kidney transplant recipients who had been followed to December 2009: 180 in the study group and 180 in a control group composed of younger patients who received grafts from non-expanded criteria donors between 1999 and 2006. A paraffin-embedded kidney biopsy was evaluated by the percentages of sclerosed glomeruli, arteriolar hyalinosis, intimal wall thickening, interstitial fibrosis, and tubular atrophy.

RESULTS

Significant differences were observed in donor age (63.50±5.46 vs 31.90±13.29 years; P<.001) and recipient age (58.40±8.80 vs 40.71±13.23 years; P<.001). Donor renal function was significantly worse among the expanded criteria group (90.80 vs 108.11 mL/min/1.73 m2; P=.006), remaining so over time in the recipient (at 1 year: 42.08 vs 63.71 [P<.001]; at 3 years: 41.25 vs 62.31 [P<.001], and at 7 years: 38.17 vs 64.18 [P<.001]). Censored 7-year graft survivals were 73% versus 87% (P<.001) with similar patient survivals (90.5% vs 95%; P=.39).

CONCLUSIONS

Selection of expanded criteria donors by kidney biopsy resulted in good renal function as well as graft and patient survivals at 7 years in older recipients.

A risk prediction model for delayed graft function in the current era of deceased donor renal transplantation

Delayed graft function (DGF) impacts short- and long-term outcomes. We present a model for predicting DGF after renal transplantation. A multivariable logistic regression analysis of 24,337 deceased donor renal transplant recipients (2003-2006) was performed. We developed a nomogram, depicting relative contribution of risk factors, and a novel web-based calculator (http://www.transplantcalculator.com/DGF) as an easily accessible tool for predicting DGF. Risk factors in the modern era were compared with their relative impact in an earlier era (1995-1998). Although the impact of many risk factors remained similar over time, weight of immunological factors attenuated, while impact of donor renal function increased by 2-fold. This may reflect advances in immunosuppression and increased utilization of kidneys from expanded criteria donors (ECDs) in the modern era. The most significant factors associated with DGF were cold ischemia time, donor creatinine, body mass index, donation after cardiac death and donor age. In addition to predicting DGF, the model predicted graft failure. A 25-50% probability of DGF was associated with a 50% increased risk of graft failure relative to a DGF risk < 25%, whereas a > 50% DGF risk was associated with a 2-fold increased risk of graft failure. This tool is useful for predicting DGF and long-term outcomes at the time of transplant.

Technical aspects of unilateral dual kidney transplantation from expanded criteria donors: experience of 100 patients

One option for using organs from donors with a suboptimal nephron mass, e.g. expanded criteria donors (ECD) kidneys, is dual kidney transplantation (DKT). In adult recipients, DKT can be carried out by several techniques, but the unilateral placement of both kidneys (UDKT) offers the advantages of single surgical access and shorter operating time. One hundred UDKT were performed using kidneys from ECD donors with a mean age of 72 years (Group 1). The technique consists of transplanting both kidneys extraperitoneally in the same iliac fossa. The results were compared with a cohort of single kidney transplants (SKT) performed with the same selection criteria in the same study period (Group 2, n = 73). Ninety-five percent of UDKTs were positioned in the right iliac fossa, lengthening the right renal vein with an inferior vena cava patch. In 69% of cases, all anastomoses were to the external iliac vessels end-to-side. Surgical complications were comparable in both groups. At 3-year follow-up, patient and graft survival rates were 95.6 and 90.9% in Group 1, respectively. UDKT can be carried out with comparable surgical complication rates as SKT, leaving the contralateral iliac fossa untouched and giving elderly recipients a better chance of receiving a transplant, with optimal results up to 3-years follow-up.

The prognostic value of frozen section preimplantation graft biopsy in the outcome of renal transplantation

INTRODUCTION

Preimplantation biopsy provides a window on the state of the renal allograft. In this study, the prognostic value of frozen section preimplantation graft biopsy was estimated and compared to regularly processed formalin-fixed biopsy.

MATERIALS AND METHODS

Seventy-four renal allograft recipients were studied. The degree of glomerulosclerosis, acute tubular necrosis, interstitial fibrosis, arteriosclerosis, and arteriolosclerosis was rapidly estimated in frozen sections and correlated to the renal function in the immediate posttransplantation period and 3 months thereafter. The histological changes were also examined in paraffin-embedded sections.

RESULTS

The histological changes observed in rapidly processed frozen sections were comparable to those observed on regularly processed sections and their differences did not reach statistical significance. Glomerulosclerosis and arteriolosclerosis were underestimated, whereas acute tubular necrosis and interstitial fibrosis were overestimated, in the frozen sections compared to permanent ones, but those differences were not statistically significant. Immediate graft function was observed in 45 patients (61%). Delayed graft function was more frequently observed among recipients with donor age above 60 years (57% vs. 32%). Serum creatinine 3 months after transplantation was above 2 mg/dL in 33 recipients (44.5%) and was positively correlated to the degree of tubular necrosis (p = 0.04) and donor age (p = 0.03). Donor age was correlated to the degree of arteriolosclerosis (p < 0.01).

CONCLUSIONS

Frozen section preimplantation biopsy gives reliable information for the situation of the graft that is related to the outcome of renal transplantation.

Donor characteristics associated with reduced survival of transplanted kidney grafts in Korea

BACKGROUND

Certain donor characteristics are known to be associated with increased graft failure in kidney transplantation.

METHODS

We analyzed donor and recipient characteristics among deceased donor kidney transplantations performed from 1995 to 2008, excluding multiorgan, pediatric, and retransplantation cases.

RESULTS

The 299 cases underwent analysis of donor characteristics including age, sex, cause of brain death, history of hypertension, cardiac arrest, length of intensive care unit (ICU) stay, last serum creatinine before organ donation, and change in creatinine during ICU stay. Cox regression analysis identified two factors that independently predicted a greater risk of graft failure. The factors were cerebrovascular accident (CVA) as the cause of brain death and a history of hypertension. Compared with donors with causes of brain death other than CVA, the adjusted hazard ratios for graft failure (GF) of kidneys from donors with CVA were 2.37 (1.34-4.19, P=.003). The hazard ratio for GF was 2.42 (1.34-4.37, P=.003) for kidneys from those with a history of hypertension. Donors meeting the criteria of CVA as the cause of brain death or history of hypertension comprised 43% of transplantation cases (128/299). Donor age and last serum creatinine level, which were identified in previous studies to show higher risks of graft failure, did not apply in our patients.

CONCLUSION

Donor history of hypertension and CVA as the cause of brain death were significant determinants of reduced graft survival after DDKT in Korea.

Use of marginal organs in kidney transplantation for marginal recipients: too close to the margins of safety?

Objective

Due to organ shortage, average waiting time for a kidney in Germany is about 4 years after start of dialysis. Number of kidney grafts recovered can only be maintained by accepting older and expanded criteria donors. The aim of this study was to analyse the impact of donor and recipient risk on kidney long-term function.

Methods

All deceased kidney transplantations were considered. We retrospectively studied 332 patients between 2002 and 2006; divided in 4 groups reflecting donor and recipient risk.

Results

Non-marginal recipients were less likely to receive a marginal organ (69 of 207, 33%) as compared to marginal recipients, of whom two-thirds received a marginal organ (p < 0.0001). Graft function significantly differed between the groups, but detrimental effect of marginal recipient status on eGFR after 12 months (-6 ml/min/1.73 qm, 95% CI -2 to -9) was clearly smaller than the effect of marginal donor status (-10 ml/min/1.73 qm, 95% CI -7 to -14).

Conclusions

As we were able to show expanded criteria donor has a far bigger effect on long-term graft function than the "extra risk" recipient. Although there have been attempts to define groups of recipients who should be offered ECD kidneys primarily the discussion is still ongoing.

A phase III study of belatacept versus cyclosporine in kidney transplants from extended criteria donors (BENEFIT-EXT study)

Recipients of extended criteria donor (ECD) kidneys are at increased risk for graft dysfunction/loss, and may benefit from immunosuppression that avoids calcineurin inhibitor (CNI) nephrotoxicity. Belatacept, a selective costimulation blocker, may preserve renal function and improve long-term outcomes versus CNIs. BENEFIT-EXT (Belatacept Evaluation of Nephroprotection and Efficacy as First-line Immunosuppression Trial-EXTended criteria donors) is a 3-year, Phase III study that assessed a more (MI) or less intensive (LI) regimen of belatacept versus cyclosporine in adult ECD kidney transplant recipients. The co-primary endpoints at 12 months were composite patient/graft survival and a composite renal impairment endpoint. Patient/graft survival with belatacept was similar to cyclosporine (86% MI, 89% LI, 85% cyclosporine) at 12 months. Fewer belatacept patients reached the composite renal impairment endpoint versus cyclosporine (71% MI, 77% LI, 85% cyclosporine; p = 0.002 MI vs. cyclosporine; p = 0.06 LI vs. cyclosporine). The mean measured glomerular filtration rate was 4-7 mL/min higher on belatacept versus cyclosporine (p = 0.008 MI vs. cyclosporine; p = 0.1039 LI vs. cyclosporine), and the overall cardiovascular/metabolic profile was better on belatacept versus cyclosporine. The incidence of acute rejection was similar across groups (18% MI; 18% LI; 14% cyclosporine). Overall rates of infection and malignancy were similar between groups; however, more cases of posttransplant lymphoproliferative disorder (PTLD) occurred in the CNS on belatacept. ECD kidney transplant recipients treated with belatacept-based immunosuppression achieved similar patient/graft survival, better renal function, had an increased incidence of PTLD, and exhibited improvement in the cardiovascular/metabolic risk profile versus cyclosporine-treated patients.

Complications of transplantation of kidneys from expanded-criteria donors

BACKGROUND

Organ shortage is the primary barrier to kidney transplantation. To maximize organ use, organs from expanded-criteria donors (ECDs) have been used increasingly. Expanded-criteria donors are defined as individuals older than 60 years or older than 50 years with at least 2 of the following risk factors: hypertension, stroke as the cause of death, or serum creatinine concentration greater than 1.5 mg/dL.

OBJECTIVE

To assess the incidence of complications posttransplantation in ECD kidneys compared with kidneys from standard-criteria cadaveric donors (SCDs).

PATIENTS AND METHODS

One hundred seventy-two patients received cadaveric renal transplants between January 1, 2006, and August 31, 2008. Donor and recipient data were collected, as well as patient and graft survival and immediate, delayed, or slow graft function. Complication rates for lymphocele, urinary leak, thrombosis, hematoma, urinary tract infection, and cytomegalovirus infection were recorded. Follow-up was for 3 to 35 months, ending on November 30, 2008.

RESULTS

Overall, mean 1-year graft survival was 86.9%, and mean creatinine concentration was 1.58 mg/dL. One incidence of primary nonfunction (0.6%) was observed. More than 25% of transplanted kidneys were from ECDs. No significant differences were noted in postoperative complications between recipients of ECD or SCD organs.

CONCLUSION

The rate of complications in recipients of ECD and SCD kidneys is comparable.

Diabetes mellitus: a risk factor for delayed graft function after deceased donor kidney transplantation

Early graft function is a major determinant of long-term outcomes after renal transplantation. Recently, recipient diabetes was identified as a risk factor for poor initial graft function in living donor renal transplantation. To further explore this association, we performed a paired analysis of deceased donor renal transplants from January 1994 to December 2005. A total of 25,523 transplant pairs were analyzed via conditional logistic regression. Diabetic recipients were older (53.16 vs. 46.75 years, p < 0.01), had a lower average panel reactive antibody (12% vs. 15%, p < 0.01) and fewer prior transplants (0.07 vs. 0.12, p < 0.01). Recipient diabetes, age, male gender, African American race, elevated peak panel reactive antibody and increased cold ischemia time were independent risk factors for delayed graft function. Specifically, diabetic recipients had increased risk of DGF on univariate analysis (odds ratio [OR] 1.32, 95% confidence interval [CI] 1.23-1.42, p < 0.01). Multivariable analysis confirmed this association but the risk differed by recipient gender; with diabetes having a greater effect in women (OR 1.66, 95% CI 1.45-1.91, p < 0.01) compared to men (OR 1.28, 95% CI 1.15-1.43, p < 0.01). It is unknown whether the deleterious impact of recipient diabetes on graft function after renal transplantation results from perioperative hyperglycemia or the chronic sequelae of diabetes.

Acceptable outcome after kidney transplantation using "expanded criteria donor" grafts

INTRODUCTION

With the worldwide shortage of donors, extra lengths are ongoing to enlarge the donor pool. One means has been a greater use of "expanded criteria donor" (ECD) grafts. A major concern regarding ECD kidneys is poor long-term graft survival. The aims of this study were to determine whether ECD grafts, as defined by the United Network for Organ Sharing, had a negative impact on graft survival and to identify the principle donor and recipient factors that influenced graft survival in our patient cohort.

METHODS

We analyzed all deceased donor renal transplants in our unit from January 1995 to October 2005, in total 1,053 transplants.

RESULTS

ECD grafts (United Network for Organ Sharing criteria) demonstrated higher rates of delayed graft function and higher early mean creatinine levels. However, there was no significant difference in 5-year graft survival. Multivariate analysis of our patient group identified donor hypertension and ischemic heart disease (IHD) as independent predictors of poor graft survival. Recipient age was significant on univariate but not on multivariate analysis. However, although younger recipients maintained acceptable 5-year graft survival despite donor hypertension, IHD, or a combination of both, these factors significantly reduced graft survival in older recipients.

CONCLUSION

Although ECD grafts had slightly worse function, 5-year survival was comparable with standard grafts in all recipients. Donor hypertension, IHD, or a combination of both significantly reduced graft survival in older recipients, not evident in younger patients. We discuss the possible factors for improved outcome with ECD grafts in our patients and the implications of our patient analysis.

Kidney Donation and Transplantation in Eurotransplant 2006–2007: Minimizing Discard Rates by Using a Rescue Allocation Policy

Context

All organ exchange organizations are challenged to maximize the utilization rate of all donors.

Objective

To investigate the benefit of a rescue allocation policy and to study the impact of donor factors on the risk of kidney discard.

Design and Setting

All 4057 donors with kidneys offered for allocation to Eurotransplant between 2006 and 2007 were included. Allocation was patient-oriented, based on a point-score system including recipient and donor factors. If an organ offer was rejected 5 times for medical reasons, allocation was switched to rescue allocation (ie, the organ was then offered in a center-oriented way). A logistic regression model was built to test whether donor factors were predictors of rescue allocation or kidney discard.

Results

Rescue allocation was used for 665 donors (16.4%); within this group, transplant rate was 54.3%, resulting in a donor discard rate of 304 donors (7.5% of total study group). The multivariate model showed that rescue allocation was used significantly more for kidneys from child donors and donors with a high creatinine level. Moreover, testing positive for hepatitis B surface antigen or antibody to hepatitis C virus was associated with an increased probability of rescue allocation. Kidney discard was significantly associated with donation after cardiac death, donor age, serum creatinine level, history of diabetes, and history of hepatitis.

Conclusions

Rescue allocation is effective in lowering donor discard rates. Even with rescue allocation, several donor factors were significantly associated with a higher discard rate. Use of liberal donor criteria and a rescue allocation policy can reduce kidney discards and thus shorten the waiting list for kidney transplantation.

Single versus dual renal transplantation from donors with significant arteriosclerosis on pre-implant biopsy

BACKGROUND

Transplantation of kidneys from donor with arteriosclerosis seen on pre-implantation biopsy has not been well studied.

METHODS

We retrospectively evaluated 20 dual kidney transplant (DKT) and 28 single (SKT) kidney transplant recipients with >or=12 months follow-up from donors with moderate arteriosclerosis (>or=25% luminal diameter narrowing).

RESULTS

Death censored graft survival was 100% and 79%, respectively (p = 0.0339). DKT recipients had significantly lower mean creatinine levels at one, three, six, and nine months and spent somewhat less time on the waiting list (181 +/- 160 vs. 318 +/- 306 d, p = 0.1429). DKT patients received kidneys from significantly older donors (64 +/- 7 vs. 54 +/- 11 yr; p = 0.0012), proportionately more expanded criteria donors (95% vs. 54%; p = 0.0029), and more donors with hypertension (81% vs. 48%, p = 0.0344) and death related to cerebrovascular accident (100% vs. 71%, p = 0.0143); however, more DKT kidneys underwent machine perfusion (95% vs. 57%, p = 0.0068). Baseline recipient variables were comparable between the two groups including age, race, gender, retransplantation, and HLA mismatch. Pre-implant biopsy was notable for similar frequencies of moderate interstitial fibrosis (10% vs. 14%, respectively) and glomerulosclerosis.

CONCLUSION

Among recipients of deceased-donor kidneys with >25% arteriosclerosis, short-term outcomes after DKT were superior to that of SKT grafts. This approach may help to expand the donor-organ pool while optimizing outcomes.

Donor-estimated GFR as an appropriate criterion for allocation of ECD kidneys into single or dual kidney transplantation

It has been suggested that dual kidney transplantation (DKT) improves outcomes for expanded criteria donor (ECD) kidneys. However, no criteria for allocation to single or dual transplantation have been assessed prospectively. The strategy of DKT remains underused and potentially eligible kidneys are frequently discarded. We prospectively compared 81 DKT and 70 single kidney transplant (SKT) receiving grafts from ECD donors aged >65 years, allocated according to donor estimated glomerular filtration rate (eGFR): DKT if eGFR between 30 and 60 mL/min, SKT if eGFR greater than 60 mL/min. Patient and graft survival were similar in the two groups. In the DKT group, 13/81 patients lost one of their two kidneys due to hemorrhage, arterial or venous thrombosis. Mean eGFR at month 12 was similar in the DKT and SKT groups (47.8 mL/min and 46.4 mL/min, respectively). Simulated allocation of kidneys according to criteria based on day 0 donor parameters such as those described by Remuzzi et al., Andres et al. and UNOS, did not indicate an improvement in 12-month eGFR compared to our allocation based on donor eGFR.

Acute Rejection Features in Dual Kidney Transplant Recipients from Elderly Donors: Comparison of Calcineurin Inhibitor-Based and Calcineurin Inhibitor-Free Immunosuppressive Protocols

Features of acute rejection in dual kidney transplant have not been studied. The aim of this study is to compare acute rejections in dual kidney transplant recipients from elderly donors on different immunosuppressive protocols. Sixty-nine patients were evaluated: 28 received calcineurin inhibitor-based (group 1) and 41 received calcineurin inhibitor-free immunosuppression (group 2). Histology of all donor kidneys was evaluated before implantation. All rejections showed tubulitis in both groups, and were classified as T cell-mediated acute rejections. Incidence and Banff grade of rejections in the two groups were not significantly different. Late rejections however, were observed in group 1 ( P < 0.01) whereas steroid-resistant rejections occurred in group 2 ( P < 0.03). C4d deposition was only observed in group 2. Occurrence of acute rejection was significantly associated with graft loss due to interstitial fibrosis/tubular atrophy in both groups. In group 1 mean serum creatinine levels of patients with rejections at six months and one year were higher than those of patients without rejections ( P < 0.03 and P < 0.009, respectively). In group 2 they were higher at six months ( P < 0.01) but not at one year. In addition, graft loss due to interstitial fibrosis/tubular atrophy occurred in 3/28 patients in group 1 (10.7%, OR= 1.95, 95%CI 1.02–3.71), and in 1/41 patients in group 2 (2.4%, OR= 0.41, 95%CI 0.07–2.24). Taken together these results suggest better renal function in patients on calcineurin inhibitor-free immunosuppression. In conclusion, acute rejections were detrimental irrespective of the type of immunosuppression, but different features were observed with each therapy. A tailored approach should be advantageous for prevention and treatment of acute rejections.

The alphabet soup of kidney transplantation: SCD, DCD, ECD--fundamentals for the practicing nephrologist

There is significant variability in the quality of deceased-donor kidneys that are used for transplantation. The quality of the donor kidney has a direct effect on important clinical outcomes such as acute rejection, delayed graft function, and patient and allograft survival. Expanded-criteria donors (ECDs) refer to older kidney donors (> or =60 yr) or donors who are aged 50 to 59 yr and have two of the following three features: Hypertension, terminal serum creatinine >1.5 mg/dl, or death from cerebrovascular accident. By definition, ECD kidneys have a 70% greater likelihood of failure compared with one from a 35-yr-old male donor who died from a motor vehicle accident. Donation after cardiac death (DCD) is a small but rapidly growing fraction of donors. An ECD kidney transplant recipient has a projected average added-life-years of 5.1 yr compared with 10 yr for a kidney recipient from a standard-criteria donor. Kidney transplantation from DCD seems to have similar allograft and patient survival compared with kidney from donation after brain death; however DCD transplantation has a 42 to 51% risk for delayed graft function (need for at least one dialysis treatment during the first week after transplantation) compared with 24% in an standard-criteria donor kidney transplant. Familiarity with the comprehensive allocation rules governing different categories of deceased-donor kidneys by the nephrologists and dialysis team providers is essential to maximizing patient autonomy and to improve the outcomes of kidney transplantation.

The deceased donor score system in kidney transplants from deceased donors after cardiac death

SUMMARY

A clinical score to identify kidneys from donors after cardiac death (DCD) with a high risk of dysfunction following transplantation could be a useful tool to guide the introduction of new algorithms for the preservation of these organs and improve their outcome after transplantation. We investigated whether the deceased donor score (DDS) system could identify DCD kidneys with higher risk of early post-transplant dysfunction. The DDS was validated in a cohort of 168 kidney transplants from donors after brain death (DBD) and then applied to a cohort of 56 kidney transplants from DCD. In the DBD cohort, the DDS grade predicted the incidence of delayed graft function (DGF) and levels of serum creatinine at 3 and 12 months post-transplant. Similarly, in the DCD cohort, the DDS grade correlated with DGF and also predicted the levels of serum creatinine at 3 and 12 months. Interestingly, the DDS identified a subgroup of marginal DCD kidneys in which minimization of cold ischemia time produced better early clinical outcome. These results highlight the impact of early interventions on clinical outcome of marginal DCD kidneys and open the possibility of using the DDS to identify those kidneys that may benefit most from therapeutic interventions before transplantation.

Kidneys from deceased donors more than 75 years perform acceptably after transplantation

BACKGROUND

Organ shortage has resulted in an increased use of expanded criteria donors for transplantation, in particular kidneys from older donors. There is limited data on the impact of donor age more than 75 years on kidney transplant outcome.

METHODS

A retrospective single-center analysis on deceased donors more than 75 years and kidney transplant outcome in an old for old setting was performed. Histologic findings (global kidney score) in graft biopsies and deceased-donor scores were evaluated to observe if this information could be helpful in predicting outcome.

RESULTS

Evaluation of data from 54 single kidney transplantations from 29 donors more than 75 years (median 77.5, range 75.2-86.1) were assessed. Ninety-three percent of the donors died of intracranial bleeding, and 69% had a history of hypertension or cardiovascular event(s). Median recipient age was 70.1 (range 50.6-82.4). Fifty-two grafts (96%) had posttransplant function. Death censored graft survival at 1, 3, and 5 years were 87%, 83%, and 83%, respectively. Patient survival was 81%, 75%, and 59% at the same time points. At follow-up at median 23 months (range 6-144 months), thirty-five recipients were alive with a median serum creatinine of 163 micromol/ L (range 103-348). Global kidney score and deceased donor score did not predict graft outcome.

CONCLUSION

Kidney transplants from deceased donors more than 75 years perform acceptable as single transplants and should be considered for use in older recipients.

Machine perfusion or cold storage in deceased-donor kidney transplantation

BACKGROUND

Static cold storage is generally used to preserve kidney allografts from deceased donors. Hypothermic machine perfusion may improve outcomes after transplantation, but few sufficiently powered prospective studies have addressed this possibility.

METHODS

In this international randomized, controlled trial, we randomly assigned one kidney from 336 consecutive deceased donors to machine perfusion and the other to cold storage. All 672 recipients were followed for 1 year. The primary end point was delayed graft function (requiring dialysis in the first week after transplantation). Secondary end points were the duration of delayed graft function, delayed graft function defined by the rate of the decrease in the serum creatinine level, primary nonfunction, the serum creatinine level and clearance, acute rejection, toxicity of the calcineurin inhibitor, the length of hospital stay, and allograft and patient survival.

RESULTS

Machine perfusion significantly reduced the risk of delayed graft function. Delayed graft function developed in 70 patients in the machine-perfusion group versus 89 in the cold-storage group (adjusted odds ratio, 0.57; P=0.01). Machine perfusion also significantly improved the rate of the decrease in the serum creatinine level and reduced the duration of delayed graft function. Machine perfusion was associated with lower serum creatinine levels during the first 2 weeks after transplantation and a reduced risk of graft failure (hazard ratio, 0.52; P=0.03). One-year allograft survival was superior in the machine-perfusion group (94% vs. 90%, P=0.04). No significant differences were observed for the other secondary end points. No serious adverse events were directly attributable to machine perfusion.

CONCLUSIONS

Hypothermic machine perfusion was associated with a reduced risk of delayed graft function and improved graft survival in the first year after transplantation. (Current Controlled Trials number, ISRCTN83876362.)

Kidney transplantation in sensitized recipients; a single center experience

A successful transplantation, across a positive crossmatch barrier, is one of the most persistent long-standing problems in the field of kidney transplant medicine. The aim of this study was to describe seven consecutive living renal transplantations in recipients with positive crossmatch for donors or positive for donor specific antibodies (DSAs). A preconditioning regimen including plasmapheresis and intravenous immunoglobulin was delivered three times a week until the crossmatch and/or DSAs became negative. Mycophenolate mofetil and tacrolimus were started two days before the plasmapheresis. The protocol was modified to include administration of anti-CD 20 antibody (rituximab, 375 mg/m(2)) from the patient number 3 through the patient number 7. All seven patients achieved negative conversion of the crossmatch or DSAs, and the kidney transplantations were successfully performed in all cases. Acute cellular rejection occurred in two patients, which were subclinical and controlled with high dose steroid treatment. Antibody-mediated rejection occurred in one patient, which was easily reversed with plasmapheresis. All recipients attained normal graft function during the 7-24 months of follow up. Our study suggests that sensitized patients can be transplanted successfully with desensitization pretreatment.

Outcomes of transplanting deceased-donor kidneys between elderly donors and recipients

Rate of acceptance of deceased-donor kidneys decreases with donor age despite the growing number of aged transplant candidates on the waiting list. In the Eurotransplant Senior Program, HLA-unmatched kidneys from deceased donors aged > or = 65 yr are transplanted regionally into recipients aged > or = 65 yr. Because we have become more willing to accept kidneys from donors aged > or = 75 yr than previous years, we performed a retrospective analysis of this subgroup. Kidneys were accepted from donors aged > or = 75 yr provided a normal creatinine on admission to the hospital, a Cockcroft-Gault creatinine clearance > 80 ml/min, and an absence of comorbidities. We compared outcomes of kidneys from donors aged > or = 75 yr with both younger-donor kidneys transplanted in the Eurotransplant Senior Program and with younger-donor HLA-matched kidneys transplanted into recipients > or = 60 yr. There were no differences in 5-yr graft and patient survival or rate of delayed graft function between groups. Graft function, measured by creatinine and creatinine clearance, differed without pattern at only three of 12 time points during 5 yr of follow-up. In conclusion, our data suggest that kidneys from deceased donors aged > or = 75 yr can be transplanted safely into recipients aged > or = 65 yr if similar donor criteria and local allocation practices are used.

The evolution of renal transplantation in clinical practice: for better, for worse?

BACKGROUND

Kidney transplantation is the optimal form of renal replacement therapy for most patients with end-stage renal disease. Attempting to improve graft and recipient survival remains challenging in clinical practice.

AIM

To identify the factors that have significantly changed over the past four decades and assess their impact on renal transplant outcomes.

DESIGN

Retrospective review of all renal transplant procedures in a single UK region.

METHODS

All 1346 renal transplant procedures performed between 1 January 1967 and 31 December 2006 were reviewed. Clinical data, histological reports and outcomes were available from a prospectively recorded database. The study period was divided into four decades to assess the changes in renal transplantation over time.

RESULTS

Significant changes that have occurred include an increase in donor and recipient ages, a greater proportion of recipients with diabetic nephropathy, a longer wait before the first transplant procedure, a fall in the incidence and impact of acute rejection, a smaller proportion of deaths due to cardiovascular disease, (P < 0.001 for all) and a trend to increased deaths from malignancy (P = 0.06) over time. In multivariate analysis, death censored graft survival was significantly influenced by the era of transplantation, donor and recipient ages, living vs. deceased donor status, and histological evidence of acute rejection, chronic allograft nephropathy, or disease recurrence. Significant factors in recipient survival were the era of transplantation, recipient age, a primary renal diagnosis of diabetic nephropathy or unspecified chronic renal failure, and biopsy proven acute rejection.

CONCLUSION

There have been major changes in the clinical practice related to renal transplantation over the past four decades; some have been beneficial and others detrimental to survival. Regular review of outcomes is essential to guide renal services development and maximize graft and recipient survival.

Renal transplantation in the elderly

Elderly patients are increasingly being considered for kidney transplantation due to a global explosion of the aging population with end-stage renal disease (ESRD). However, mounting scarcity of available organs for transplant has led to a wider disparity between organ supply and demand. Consequently, the criteria for accepting kidneys for transplantation have been extended in an attempt to allow the use of organs from elderly donors or those with significant co-morbidities, so-called "expanded criteria donor" (ECD) kidneys. Excellent outcomes have been achieved from ECD kidneys with appropriate donor and recipient profiling and selection. With increasing recovery efforts directed at older donors, the concept of age-matching is becoming more accepted as a method of optimizing utilization of organs in elderly donors and recipients. Utilization of pulsatile perfusion has further improved ECD outcomes and helped the decision-making process for the UNOS (United Network for Organ Sharing) offer. However, age-related immune dysfunction and associated co-morbidities make the elderly transplant recipients ever more susceptible to complications associated with immunosuppressive agents. Consequently, the elderly population is at a higher risk to develop infections and malignancy in the post-transplant period notwithstanding improved transplant outcomes. Appropriate immunosuppressive agents and dosages should be selected to minimize adverse events while reducing the risk of acute rejections and maximizing patient and renal allograft survival.

A systematic review of kidney transplantation from expanded criteria donors

BACKGROUND

During the past few years, there has been renewed interest in the use of expanded criteria donors (ECD) for kidney transplantation to increase the numbers of deceased donor kidneys available. More kidney transplants would result in shorter waiting times and limit the morbidity and mortality associated with long-term dialysis therapy.

STUDY DESIGN

Systematic review of the literature.

SETTING & POPULATION

Kidney transplantation population.

SELECTION CRITERIA FOR STUDIES

Studies were identified by using a comprehensive search through MEDLINE and EMBASE databases. Inclusion criteria were case series, cohort studies, and randomized controlled trials assessing kidney transplantation in adult recipients using ECDs.

PREDICTOR

A special focus was given to studies comparing the evolution of kidney transplantation between standard criteria donors (defined as a donor who does not meet criteria for donation after cardiac death or ECD) and ECDs (defined as any brain-dead donor aged > 60 years or a donor aged > 50 years with 2 of the following conditions: history of hypertension, terminal serum creatinine level >or= 1.5 mg/dL, or death resulting from a cerebrovascular accident).

OUTCOMES

Criteria used to define and select ECDs, practice patterns, long-term outcomes, early complications, and some patient issues, such as selection criteria and immunosuppressive management.

RESULTS

ECD kidneys have worse long-term survival than standard criteria donor kidneys. The optimal ECD kidney for donation depends on adequate glomerular filtration rate and acceptable donor kidney histological characteristics, albeit the usefulness of biopsy is debated.

LIMITATIONS

This review is based mainly on data from observational studies, and varying amounts of bias could be present. We did not attempt to quantitatively analyze the effect of ECD kidneys on kidney transplantation because of the huge heterogeneity found in study designs and definitions of ECD.

CONCLUSIONS

Based on the available evidence, we conclude that patients younger than 40 years or scheduled for kidney retransplantation should not receive an ECD kidney. Patients 40 years or older, especially with diabetic nephropathy or nondiabetic disease, but a long expected waiting time for kidney transplantation, show better survival receiving an ECD kidney than remaining on dialysis therapy.

Impact of cold ischemia time on renal allograft outcome using kidneys from young donors

Prolonged cold ischemia time (CIT) is associated with delayed graft function and worse kidney transplant (KT) outcome, but the effect of CIT on long-term allograft survival in KT from younger donors has not been well established. We investigated the predictive value of CIT exposure on long-term death-censored graft loss in 829 KT recipients from younger donors (<50 years) that were performed in our center between 1991 and 2005. Overall death-censored graft failure rate was significantly higher in CIT>or=19 h group versus CIT<19 h group (26 vs. 16.5%; P = 0.002). Significant differences were also observed when patients with primary nonfunctioning graft were excluded (21 vs. 14%; P = 0.020) and in patients who received tacrolimus plus mycophenolate mofetil (12 vs. 4%; P = 0.05). By multivariate Cox analysis, CIT was found to be independently associated with death-censored graft loss with a 20% increase for every 5 h of CIT [relative risk (RR) 1.04; 95% Confidence Interval (CI): 1.01-1.1; P = 0.021]. Likewise, graft loss risk significantly increased in CIT>or=19 h group versus CIT<19 h group (RR 1.5; 95%CI: 1.1-2.1; P = 0.023). Prolonged CIT is an independent predictor of graft survival in KT from younger donors. Efforts at minimizing CIT (<19 h) should improve transplant outcome significantly in this population.

Donor biopsy and kidney transplant outcomes: an analysis using the Organ Procurement and Transplantation Network/United Network for Organ Sharing (OPTN/UNOS) database

BACKGROUND

Although the degree of glomerulosclerosis on pretransplant donor biopsy is one criterion used in the decision to accept a deceased donor kidney, its relationship with graft survival remains controversial. This study compared graft survival with the degree of glomerulosclerosis found on donor biopsy. We also examined the agreement in degree of glomerulosclerosis between paired kidneys.

METHODS

Biopsy results from 12,129 adult deceased donor transplants between January 1, 2000 and December 31, 2005 were identified in the Organ Procurement and Transplantation Network/United Network for Organ Sharing data, as of September 11, 2006. Of these, 2696 donors had both kidneys biopsied and subsequently transplanted.

RESULTS

Among the groups with greater than 5% glomerulosclerosis, there was no statistically significant difference in graft survival rates (log-rank, P=0.44). The overall graft survival rates of the 0-5% group were significantly superior to those of the >5% groups (1-, 3-, and 5-year rates: 85.9%, 72.4%, and 59.0% for 0-5% group vs. 81.6%, 68.1%, and 53.6% for >5% group, log-rank P<0.001). Agreement between paired kidneys from the same donor was highest for the 0-5% glomerulosclerosis groups (90.6% for pairs with 0-5% glomerulosclerosis in the left kidney vs. 42.5% for pairs with >5% glomerulosclerosis in the left kidney).

CONCLUSION

Donor kidneys with less than 6% glomerulosclerosis were associated with better graft outcomes and intrapair agreement in the degree of glomerulosclerosis. Among kidneys with greater than 5% glomerulosclerosis, the degree of glomerulosclerosis did not help predict graft outcomes. Sampling error may contribute to the lack of outcome differences seen among these kidneys, given the low intrapair agreement.