A review of the kidneys that nobody wanted: determinants of optimal outcome

The use of marginal kidneys in dual kidney transplantation to expand kidney graft utilization

PURPOSE OF REVIEW

The purpose of this review is to chronicle the history of dual kidney transplantation (DKT) and identify opportunities to improve utilization of marginal deceased donor (MDD) kidneys through DKT.

RECENT FINDINGS

The practice of DKT from adult MDDs dates back to the mid-1990s, at which time the primary indication was projected insufficient nephron mass from older donors. Multiple subsequent studies of short- and long-term success have been reported focusing on three major aspects: Identifying appropriate selection criteria/scoring systems based on pre- and postdonation factors; refining technical aspects; and analyzing longer-term outcomes. The number of adult DKTs performed in the United States has declined in the past decade and only about 60 are performed annually. For adult deceased donor kidneys meeting double allocation criteria, >60% are ultimately not transplanted. MDDs with limited renal functional capacity represent a large proportion of potential kidneys doomed to either discard or nonrecovery.

SUMMARY

DKT may reduce organ discard and optimize the use of kidneys from MDDs. New and innovative technologies targeting ex vivo organ assessment, repair, and regeneration may have a major impact on the decision whether or not to use recovered kidneys for single or DKT.

Dual kidney transplants from adult marginal donors: Review and perspective

The practice of dual kidney transplantation (DKT) from adult marginal deceased donors (MDDs) dates back to the mid-1990s with initial pioneering experiences reported by the Stanford and Maryland groups, at which time the primary indication was estimated insufficient nephron mass from older donors. Multiple subsequent studies of short and long-term success have been reported focusing on three major aspects of DKT: Identifying appropriate selection criteria and developing scoring systems based on pre- and post-donation factors; refining technical aspects; and analyzing mid-term outcomes. The number of adult DKTs performed in the United States has declined in the past decade and only about 60 are performed annually. For adult deceased donor kidneys meeting double allocation criteria, >60% are ultimately not transplanted. Deceased donors with limited renal functional capacity represent a large proportion of potential kidneys doomed to either discard or non-recovery. However, DKT may reduce organ discard and optimize the use of kidneys from MDDs. In an attempt to promote utilization of MDD kidneys, the United Network for Organ Sharing introduced new allocation guidelines pursuant to DKT in 2019. The purpose of this review is to chronicle the history of DKT and identify opportunities to improve utilization of MDD kidneys through DKT. This article is protected by copyright. All rights reserved.

The discard of deceased donor kidneys in the UK

It is essential to minimize the unnecessary discard of procured deceased donor kidneys, but information on discard rates and the extent to which discard can be avoided are limited. Analysis of the UK Transplant Registry revealed that the discard rate of procured deceased donor kidneys has increased from 5% in 2002-3 to 12% in 2011-12. A national offering system for hard-to-place kidneys was introduced in the UK in 2006 (the Declined Kidney Scheme), but just 13% of kidneys that were subsequently discarded until 2012 were offered through the scheme. In order to examine the appropriateness of discard, 20 consecutive discarded kidneys from 13 deceased donors were assessed to determine if surgeons agreed with the decision that they were not implantable. Donors had a median (range) age of 67 (31-80) yr. Kidneys had been offered to a median of 3 (1-12) centers before discard. Four (20%) of the discarded kidneys were thought to be usable, and nine (45%) were possibly usable. As a result of these findings, major changes to the UK deceased donor kidney offering system have been implemented, including simultaneous offering and broader entry criteria for hard-to-place kidneys. Organizational changes are necessary to improve utilization of deceased donor kidneys.

Determinants of discard of expanded criteria donor kidneys: impact of biopsy and machine perfusion

We examined factors associated with expanded criteria donor (ECD) kidney discard. Scientific Registry of Transplant Recipients (SRTR)/Organ Procurement and Transplantation Network (OPTN) data were examined for donor factors using logistic regression to determine the adjusted odds ratio (AOR) of discard of kidneys recovered between October 1999 and June 2005. Logistic and Cox regression models were used to determine associations with delayed graft function (DGF) and graft failure. Of the 12,536 recovered ECD kidneys, 5139 (41%) were discarded. Both the performance of a biopsy (AOR = 1.21, p = 0.02) and the degree of glomerulosclerosis (GS) on biopsy were significantly associated with increased odds of discard. GS was not consistently associated with DGF or graft failure. The discard rate of pumped ECD kidneys was 29.7% versus 43.6% for unpumped (AOR = 0.52, p < 0.0001). Among pumped kidneys, those with resistances of 0.26-0.38 and >0.38 mmHg/mL/min were discarded more than those with resistances of 0.18-0.25 mmHg/mL/min (AOR = 2.5 and 7.9, respectively). Among ECD kidneys, pumped kidneys were less likely to have DGF (AOR = 0.59, p < 0.0001) but not graft failure (RR = 0.9, p = 0.27). Biopsy findings and machine perfusion are important correlates of ECD kidney discard; corresponding associations with graft failure require further study.

Renal Grafts From Elderly Donors: Histological Studies and Long-Term Results

To satisfy the increasing requests for renal grafts, elderly donors are increasingly accepted for kidney transplant at many centers. The main unresolved question is the long-term effect on graft survival of potential histological lesions due to donor age. We present a prospective histological study performed from January 1997 to December 2001 on 184 consecutively transplanted renal grafts in which the only criterion for graft acceptance was a normal value of serum creatinine upon admission to the intensive care unit independent of donor age. At the end of the study, 57 recipients (31%) of mean age 55 years (range 39 to 67 years) received a renal graft from donors aged more than 60 years (mean age 66 years; range 60 to 75 years), this cohort denoted as older donor kidney transplant group (ODKTG) and 127 recipients (69%) with a mean age of 49 years (range 21 to 63 years) received a renal graft from donors whose age was lower than 60 years (mean age 49 years; range 16 to 59 years), a cohort denoted as the younger donor kidney transplant group (YDKTG). The two groups were comparable for time of dialysis, cold ischemia time, immunosuppression therapy, grading of histological damage. At the end of the study with a mean follow-up of 5.6 years (range 3.5 to 7.5 years), primary graft nonfunction and delayed graft function were significantly more represented in the ODKTG than the YDKTG. Cumulative patient and graft survival was 84.3% and 79.4% in the ODKTG, respectively, and 93.8% and 85.9% in the YDKTG, respectively (P = NS). Cumulative serum creatinine values were 1.98 mg/100 mL in ODKTG and 1.65 mg/100 mL in YDKTG (P = NS). In conclusion, renal grafts from older donors presented histological damage comparable to that seen among renal grafts from younger donors.

Retrospective follow-up of transplantation of kidneys from 'marginal' donors

The organ shortage has led to extend the procurement to kidneys from 'marginal' donors. As a result, an increasing number of kidneys are discarded, but an extended analysis of the validity of the clinical decision to accept or decline a marginal graft remains to be determined. We have retrospectively analyzed the outcome of 170 kidney transplantations, performed in eight renal transplantation centers between 1992 and 1998. Study group included transplantation from donors accepted after refusal for poor donor or graft quality by at least two centers. Control group included 170 paired recipients from kidneys unanimously accepted by all centers. Main causes of kidney refusal included impaired donor hemodynamics (28%), abnormal pre-harvesting serum creatinine (22%), advanced age in donors (15%), and donor atheroma (14%). The 5-year patient survival (88.2% in the study group and 88.9% in controls) and graft survival (70.4% in the study group and 76.7% in controls, P=0.129) were not significantly different. Delayed graft function occurred significantly more often in the study group patients than in controls patients (63 vs 32%, P<0.0001). Primary non-functioning kidneys were significantly more frequently observed in study patients than in controls (7.7 vs 1.8%, P=0.01). Mean creatinine clearance was significantly lower in the study group patients compared with controls during the post-transplant course. Our results suggest that these initially discarded kidneys provide satisfactory survival rates despite their impaired early functional recovery and poorer long-term renal function, and therefore might be considered acceptable for transplantation in the context of organ shortage.

The Fate of Organs Refused Locally and Transplanted Elsewhere

The number of kidney allografts procured from deceased donors has been fairly constant in the past few years, while organs from living donors steadily increase. In our program, existing protocols refused some kidneys which were subsequently accepted and transplanted at other hospitals. Thus, a review of our criteria to accept kidneys became necessary.

METHODS

We studied the outcome of all kidneys refused by us but transplanted in other programs between 2002 and 2004. The data analyzed included ID no. donor, transplant center, procurement date, donor age, ischemic times, recipient alive or dead, creatinine level (when it was offered), initial function, hypertension, diabetes mellitus, biopsy, reason why the kidney was not accepted in our program, kidney functioning or lost, and cause of graft failure. The chi-square, Fisher, and t tests were used to analyze our data; P values of <.05 were regarded as significant.

RESULTS

Originally 137, we excluded kidneys exported due to mandatory sharing (26 of 137 = 18.97%) and multiorgan placement (10 of 137 = 7.3%). Thus, 101 kidneys were not accepted by us because they did not meet the existing criteria of our program, but were accepted elsewhere. Reasons for nonacceptance were divided into donor quality, donor social history, donor age, donor size/weight, positive serological test, as well as organ preservation time, organ anatomical damage, elevated creatinine, abnormal urinalysis, abnormal biopsy, and decreased urine output. Donor issues were 66 of 101 (65.3%) with a graft loss of 13.6%, and organ issues were 35 of 101 (34.7%) with a graft loss of 66.6%. Donor quality totaled 24 of 66 (36.4%) and donor social history totaled 20 of 66 (30.3%); these were the most common causes for kidney nonacceptance related to donor issues. Reasons related to organ quality included elevated creatinine (15 of 35 = 42.9%; graft loss, 46.6%), and abnormal biopsy (9 of 35 = 25.7%; graft loss, 11.1%) and organ anatomical damage (4 of 35 = 11.4%; graft loss, 75%) (P = .42). Graft loss was more frequent with creatinine levels above 2.4 mg/dL (P < .001, RR gf = 1.5). Long-term fate of these 101 kidneys transplanted elsewhere: 82 (81.2%) were still working while 19 (18.8%) were lost. The causes of graft loss were renal artery thrombosis (42.1%), renal venous thrombosis (26.3%), death for other reasons (15.8%), graft never worked (10.5%), and ESRD (5.7%). The results suggest that the criteria for refusal related to donor issues, including hypertension, diabetes mellitus, donor age and donor size, should be revised owing to the low percentage of graft loss. Other donor issues such as positive serological test and donor social history (drug use, alcoholism) represent a serious potential risk for the health of recipients; for this reason, considering these persons as possible donors is very difficult irrespective of the graft outcome. Kidney refusals related to organ issues (especially elevated creatinine and anatomical damage) due to the very high percentage of graft loss should be considered high risk and probably be excluded. The increase in the demand of kidneys to be transplanted is a very important reason for a continuous and systematic review of donor exclusion criteria in every transplant program. The results presented here have helped us to improve both our outcomes and utilizations based on scientific evidence.

Kidney Transplantation From 1119 Deceased Donors in Finland, 1991 to 2003: Impact of Donor Factors

We assessed the effect of donor factors on the recovery and quality of cadaveric kidney transplant function. During 1991 to 2003, 2006 kidney grafts were derived from 1119 heart-beating donors in Finland. The annual mean age of donors increased from 33 to 46 years, with a significant decrease in the proportion of high-energy trauma and gunshot wounds and with an increased proportion of donors with coronary disease, hypertension, or cardiopulmonary resuscitation and surgical/radiological interventions before death. The transplant team's share of kidney retrievals increased from 50% to nearly 100%. In uni- and multivariate analyses all these factors had significant effects on the onset and quality of early graft function; however, this effect practically vanished by 1 year posttransplant. Of all studied donor factors, only donor cytomegalovirus (CMV) status significantly affected long-term survival, with donor CMV-positive grafts having 5% worse survival at 5 years. The 1-year graft survival improved from 90.9% to 96.2% and mean 1-year creatinine decreased from 121 micromol/L to 109 micromol/L during these 13 years, showing that the worsening trends in donors quality were compensated by improvements in other aspects of the process.

Impact of the Expanded Criteria Donor Allocation System on the Use of Expanded Criteria Donor Kidneys

BACKGROUND

The U.S. Organ Procurement and Transplantation Network recently implemented a policy allocating expanded criteria donor (ECD) kidneys by waiting time alone. ECD kidneys were defined as having a risk of graft failure > or = 1.7 times that of ideal donors. ECDs include any donor > or = 60 years old and donors 50 to 59 years old with at least two of the following: terminal creatinine >1.5 mg/dL, history of hypertension, or death by cerebrovascular accident. The impact of this policy on use of ECD kidneys is assessed.

METHODS

The authors compared use of ECD kidneys recovered in the 18 months immediately before and after policy implementation. Differences were tested using t test and chi2 analyses.

RESULTS

There was an 18.3% increase in ECD kidney recoveries and a 15.0% increase in ECD kidney transplants in the first 18 months after policy implementation. ECD kidneys made up 22.1% of all recovered kidneys and 16.8% of all transplants, compared with 18.8% (P<0.001) and 14.5% (P<0.001), respectively, in the prior period. The discard rate was unchanged. The median relative risk (RR) for graft failure for transplanted ECD kidneys was 2.07 versus 1.99 in the prepolicy period (P=not significant); the median RR for procured ECD kidneys was unchanged at 2.16. The percentage of transplanted ECD kidneys with cold ischemia times (CIT) <12 hr increased significantly; the corresponding percentage for CIT > or = 24 hr decreased significantly.

CONCLUSIONS

The recent increase in ECD kidney recoveries and transplants appears to be related to implementation of the ECD allocation system.

Expanding the donor pool to increase renal transplantation

INTRODUCTION

The goal of the Eurotransplant renal allocation scheme is to provide every patient on the waiting list with a reasonably balanced opportunity for a donor offer. New initiatives were taken in order to maximize donor usage while maintaining a successful transplant outcome.

METHODS

Two Eurotransplant projects were launched in order to accommodate changes in donor and recipient profiles. A re-addressing of the non-heart-beating donor pool was undertaken and an allocation scheme in which organs from donors aged >65 are allocated to recipients aged >65 [the Eurotransplant Senior Programme (ESP)] was introduced.

RESULTS

Especially in The Netherlands, an enormous increase in the number of non-heart-beating donor kidneys has been observed, however with a pace-keeping reduction in heart-beating donors. The organization-wide implementation of the ESP has been successful. The 3 year graft survival rates for these age-matched transplants were as good as the human leukocyte antigen (HLA)-matched transplants (64 vs 67%) (P = 0.4).

CONCLUSION

Within the framework of sound research, the utmost flexibility and creativity is needed to keep or even increase the number of renal transplants when faced with a quantitatively stagnating but qualitatively deteriorating donor pool. Both the non-heart-beating donor protocol and the ESP have proven to be quite successful in achieving this goal without compromising the outcome for the individual end-stage renal disease patient.

Late deterioration of organ transplants: a problem in injury and homeostasis

The late deterioration of allografts remains a problem despite improvements in short-term and long-term graft survival. The previous concept that late deterioration reflects a specific disease -- chronic rejection -- is being replaced. The new view is that many factors are involved in late deterioration, including the age and pretransplant condition of the organ, injury from brain death, injury from the transplant process, T cell-mediated and antibody-mediated rejection (in some cases reflecting poor compliance with immunosuppressive drugs) and post-transplant organ-specific stresses in the new environment, including drug toxicity, infectious agents, hypertension and lipids. Ultimately these stresses interact with the intrinsic limitations in repair and homeostasis in the tissues of the organ, producing characteristic syndromes. The most important recent advance has been the emergence of potent immunosuppressive drug combinations that have greatly reduced rejection.

Evaluation of the Eurotransplant Senior Program. The results of the first year

On 4 January 1999, the Eurotransplant Senior Program (ESP) was implemented within the Eurotransplant kidney allocation scheme.

PATIENTS AND METHODS

Kidneys obtained from donors aged over 65 years of age (65+) were allocated to a selected group of nonimmunized 65+ patients undergoing their first transplant. All transplants were performed locally to minimize cold-ischemic time. All transplants performed with kidneys from elderly donors that were allocated via ESP (ESP group) were compared to transplants performed with similar kidneys allocated via the standard renal allocation system (control group). Initial kidney function and 1-year graft outcome were assessed.

RESULTS

In 1999, 227 ESP and 102 control transplants were performed. The duration of cold-ischemic time was 12 and 19 h for the ESP and control groups, respectively. No rejection episodes occurred in 60% and 67% of the ESP patients and controls, respectively, while a direct kidney function was observed in 59% of ESP and 49% of control patients. The 1-year graft survival rates, censoring for graft losses due to deaths in patients with functioning grafts, were 86% and 79%, respectively.

CONCLUSION

An old-for-old renal allocation algorithm can be successful provided that risk factors, such as cold-ischemic time, are reduced.

The marginal kidney donor

In parallel with increased clinical demand, less than optimal or so-called marginal kidney grafts are being used for transplantation. In addition to donor age, it appears that several factors may impact negatively on the quality of the graft. Most importantly, a more precise definition of the term 'marginal graft' is needed. The present review analyzes potential risk factors, suggests scoring systems for a more precise definition, and discusses potential treatment options to improve the quality of marginal grafts.

Severe glomerular sclerosis is not associated with poor outcome after kidney transplantation

BACKGROUND

The increased utilization of expanded criteria kidney donors has necessitated the reevaluation of multiple donor risk factors to insure the best outcome from this valuable resource. Reports of decreased graft survival in recipients of kidneys from donors with > or =20% glomerular sclerosis (GS) have led many transplant centers to refuse these donor kidneys. The purpose of this study is to compare outcome in recipients of cadaveric donor kidneys with > or =20% GS versus those with <20% or no GS at our center.

METHODS

We retrospectively reviewed 18 donor and 19 recipient and outcome variables in 89 recipients of kidneys, which were biopsied at the time of transplantation, between February 1995 and November 1998. We evaluated outcome based upon the percent of GS and the degree of vasculopathy.

RESULTS

Donors with > or =20% GS were older and had more hypertension. Recipients of kidneys with > or =20% GS were older, had higher serum creatinine values at 1 and 2 years, but similar rates of delayed graft function and 2-year graft survival. Vasculopathy did not correlate to any important donor criteria except the percent GS. However, serum creatinine was significantly higher in recipients of kidneys with moderate vasculopathy versus none, up to 2 years after transplantation. There was no significant difference in graft loss based upon vasculopathy.

CONCLUSION

Kidneys from donors with > or =20% GS provide excellent outcome similar to kidneys from donors with no GS.

Dual kidney transplantation: older donors for older recipients

BACKGROUND

Dual kidney transplantation, the transplantation of both donor kidneys into a single recipient, allows increased use of expanded criteria donors (eg, older donors with a history of hypertension) to alleviate the disparity between available donors and potential recipients. We evaluated outcomes in our dual kidney transplant program that started in 1995.

STUDY DESIGN

A retrospective comparison of donor and recipient data between recipients of dual (n = 41) versus single (n = 199) cadaveric renal transplants from February 1, 1995, to March 22, 1998, was performed. Dual kidney transplantation was selectively performed when the calculated donor admission creatinine clearance was less than 90 mL/min and the donor age was greater than 60 years, or if the donor had an elevated terminal serum creatinine. Every attempt was made to age- and size-match the donor and recipients.

RESULTS

Recipients of dual kidneys had donors who were older than single kidney donors (59 +/- 12 versus 42 +/- 17 years respectively, p < 0.0001) and had more hypertension (51% versus 29%, p = 0.024). Average urine output was lower in the dual versus single kidney group (252 +/- 157 versus 191 +/- 70 mL/hr, p = 0.036). Donors for dual kidney recipients had a lower donor admission creatinine clearance of 82 +/- 28 mL/min versus 105 +/- 45 mL/min in the single kidney group (p = 0.005). Recipients of dual versus single kidneys were older (58 +/- 11 versus 47 +/- 12 years, p > 0.0001). Dual versus single kidney recipients had similar serum creatinines up to 2 years posttransplant (1.6 +/- 0.3 versus 1.6 +/- 0.7 mg/dL at 2 years, p = NS) and a comparable incidence of delayed graft function (24% versus 33%, p = NS) and 3-month posttransplant creatinine clearance (54 +/- 23 versus 57 +/- 25 mL/min, p = NS). One-year patient and graft survival for single kidney transplantation was 97% and 90%, respectively, and 98% and 89% for dual kidney transplantation (p = NS).

CONCLUSIONS

Dual kidney donors were significantly older, had more hypertension, lower urine outputs, and lower donor admission creatinine clearance. Despite these differences, dual kidney recipients had comparable postoperative function, outcomes, and survival versus single kidney recipients. We believe selective use of dual kidney transplantation can provide excellent outcomes to recipients of kidneys from older donors with reduced renal function.

Outcome of kidney transplantation from high-risk donors is determined by both structure and function

METHOD

Despite the need to expand the donor pool, it is unclear what parameters should be used. The value of donor renal pathology and calculated creatinine clearance (CrCl) in determining recipient outcome was assessed in 57 kidney transplants from 34 donors in whom pretransplant renal biopsies were performed because of age > or =60, hypertension, and/or vascular disease. We retrospectively compared clinical outcomes in these recipients and 57 control recipients selected to have the same baseline demographics but receiving transplants from low risk donors who were significantly younger (32+/-13.9 vs. 61+/-7.3 years) and lighter weight (71+/-18.1 vs. 84+/-20.2 kg) than the high-risk donors (P<.001 for both).

RESULTS

Recipients of high-risk kidneys had a higher incidence of delayed graft function, defined by a <10% fall in serum creatinine (Cr) in the first 24 hr, (56% vs. 30%, P<.01), a higher incidence of rejection (60% vs. 37%, P = .02) and a higher Cr level (197+/-64 vs. 144+/-54 micromol/L at 18 months, P<.005). Graft and patient survival were similar; 12% and 5% vs. 91% and 9% in high-risk vs. control groups, respectively (P = NS). Donor renal pathology was scored 0-3 (none to severe disease) in four areas: glomerulosclerosis, interstitial fibrosis, tubular atrophy, and vascular disease. A donor vessel score of 3/3 was associated with a 100% incidence of delayed graft function and a mean 1-year Cr level of 275+106 micromol/L (compared with 43% and 192+54 micromol/L in those with lower vessel scores, P<.05). Calculated donor CrCl <100 ml/min was associated with higher recipient Cr levels at 1 year, 240+/-95 micromol/L vs. 180+/-54 micromol/L in recipients of kidneys from donors with CrCl levels >100 ml/min (P<.05). The mean 1-year Cr level was 320+/-102 micromol/L in recipients with both a vascular score of 3/3 and a donor CrCl <100 ml/min and 184+/-63 micromol/L in those with neither factor (P = .001).

CONCLUSION

Calculated donor CrCl and donor vascular pathology predict recipient graft function and may be helpful in selecting high-risk donors for single kidney transplantation.