Double versus single renal allografts from aged donors

Clinical Phenotypes of Dual Kidney Transplant Recipients in the United States as Identified through Machine Learning Consensus Clustering

Background and Objectives: Our study aimed to cluster dual kidney transplant recipients using an unsupervised machine learning approach to characterize donors and recipients better and to compare the survival outcomes across these various clusters. Materials and Methods: We performed consensus cluster analysis based on recipient-, donor-, and transplant-related characteristics in 2821 dual kidney transplant recipients from 2010 to 2019 in the OPTN/UNOS database. We determined the important characteristics of each assigned cluster and compared the post-transplant outcomes between clusters. Results: Two clinically distinct clusters were identified by consensus cluster analysis. Cluster 1 patients was characterized by younger patients (mean recipient age 49 ± 13 years) who received dual kidney transplant from pediatric (mean donor age 3 ± 8 years) non-expanded criteria deceased donor (100% non-ECD). In contrast, Cluster 2 patients were characterized by older patients (mean recipient age 63 ± 9 years) who received dual kidney transplant from adult (mean donor age 59 ± 11 years) donor with high kidney donor profile index (KDPI) score (59% had KDPI ≥ 85). Cluster 1 had higher patient survival (98.0% vs. 94.6% at 1 year, and 92.1% vs. 76.3% at 5 years), and lower acute rejection (4.2% vs. 6.1% within 1 year), when compared to cluster 2. Death-censored graft survival was comparable between two groups (93.5% vs. 94.9% at 1 year, and 89.2% vs. 84.8% at 5 years). Conclusions: In summary, DKT in the United States remains uncommon. Two clusters, based on specific recipient and donor characteristics, were identified through an unsupervised machine learning approach. Despite varying differences in donor and recipient age between the two clusters, death-censored graft survival was excellent and comparable. Broader utilization of DKT from high KDPI kidneys and pediatric en bloc kidneys should be encouraged to better address the ongoing organ shortage.

Delayed Graft Function in Kidney Transplant: Risk Factors, Consequences and Prevention Strategies

Background. Delayed graft function is a frequent complication of kidney transplantation that requires dialysis in the first week posttransplant. Materials and Methods. We searched for the most relevant articles in the National Institutes of Health library of medicine, as well as in transplantation, pharmacologic, and nephrological journals. Results. The main factors that may influence the development of delayed graft function (DGF) are ischemia–reperfusion injury, the source and the quality of the donated kidney, and the clinical management of the recipient. The pathophysiology of ischemia–reperfusion injury is complex and involves kidney hypoxia related to the duration of warm and cold ischemia, as well as the harmful effects of blood reperfusion on tubular epithelial cells and endothelial cells. Ischemia–reperfusion injury is more frequent and severe in kidneys from deceased donors than in those from living donors. Of great importance is the quality and function of the donated kidney. Kidneys from living donors and those with normal function can provide better results. In the peri-operative management of the recipient, great attention should be paid to hemodynamic stability and blood pressure; nephrotoxic medicaments should be avoided. Over time, patients with DGF may present lower graft function and survival compared to transplant recipients without DGF. Maladaptation repair, mitochondrial dysfunction, and acute rejection may explain the worse long-term outcome in patients with DGF. Many different strategies meant to prevent DGF have been evaluated, but only prolonged perfusion of dopamine and hypothermic machine perfusion have proven to be of some benefit. Whenever possible, a preemptive transplant from living donor should be preferred.

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.

Long-term survival benefit from dual kidney transplantation using kidneys from donors with very extended criteria - A French cohort between 2002 and 2014

BACKGROUND

This national multicenter retrospective cohort study aimed to assess the long-term outcomes of dual kidney transplantation (DKT) and compare them with those obtained from single kidney transplantation (SKT).

METHODS

Our first analysis concerned all first transplants performed between May 2002 and December 2014, from marginal donors, defined as brain death donors older than 65, with an estimated glomerular filtration rate (eGFR) lower than 90 ml/min/1.73m². The second analysis was restricted to transplants adequately allocated according to the French DKT program based on donor eGFR: DKT for eGFR between 30 and 60, SKT for eGFR between 60 and 90 ml/min/1.73m². Recipients younger than 65 years or with a panel-reactive antibody percentage ≥ 25% were excluded.

RESULTS

The first analysis included 461 DKT and 1131 SKT. DKT donors were significantly older (77.6 versus 74 years), had a more frequent history of hypertension and a lower eGFR (55.1 versus 63.6 ml/min/1.73m²). While primary nonfunction and delayed graft function did not differ between SKT and DKT, 1-year eGFR was lower in SKT recipients (39 vs. 49 ml/min/1.73m², P < 0.001). Graft survival was significantly better in DKT, even after adjustment for recipient and donor risk factors. Nevertheless, patient survival did not differ between these groups. The second analysis included 293 DKT and 687 SKT adequately allocated with donor eGFR and displayed similar results but with a smaller benefit in terms of graft survival.

CONCLUSIONS

In a context of organ shortage, DKT is a good option for optimizing the use of kidneys from very expanded criteria donors.

Retrieved but not transplanted kidneys: how to limit the losses? A retrospective national study

Despite the organ shortage, a significant number of deceased donor kidneys are retrieved but not transplanted (RNTK). This study aims to describe and analyze the main causes of potential grafts discard and to propose adequate solutions. We collected data from the Cristal database of the French Biomedicine Agency about RNTK over one year. Expert opinion was taken from urologists with extensive expertise in renal transplantation. They retrospectively analyzed each record to assess the appropriateness of each graft refusal and subsequent kidney discard. Of 252 kidneys were retrieved but not transplanted in France over one year. The main reasons for discard were vascular abnormalities in 43.7% (n = 110), suspicion of malignant tumor in 18.7% (n = 47), and severe histological lesions on preimplantation biopsy in 12.3% (n = 31). The reason for kidney refusal was undetermined in 4.8% (n = 12). Iatrogenic lesions were responsible for 26.2% (n = 66). Overall, 46.0% (n = 16) and 25.0% (n = 63) of the grafts were, respectively, properly and improperly denied, and the analysis was not possible in 29.0% (n = 73). In total, 36.9% of RNTK could have been transplanted. Reduction of iatrogenic lesions, improvement of microsurgical repair skills, and proper histological examination are necessary to reduce the number of RNTK. A prospective study applying the proposed principles is undoubtedly essential to complete this work.

Kidney transplantation in the extremely elderly from extremely aged deceased donors: a kidney for each age

BACKGROUND

Advances in life expectancy have led to an increase in the number of elderly people with end-stage renal disease (ESRD). Scarce information is available on the outcomes of kidney transplantation (KT) in extremely elderly patients based on an allocation policy prioritizing donor-recipient age matching.

METHODS

We included recipients ≥75 years that underwent KT from similarly aged deceased donors at our institution between 2002 and 2015. Determinants of death-censored graft and patient survival were assessed by Cox regression.

RESULTS

We included 138 recipients with a median follow-up of 38.8 months. Median (interquartile range) age of recipients and donors was 77.5 (76.3-79.7) and 77.0 years (74.7-79.0), with 22.5% of donors ≥80 years. Primary graft non-function occurred in 8.0% (11/138) of patients. Cumulative incidence rates for post-transplant infection and biopsy-proven acute rejection (BPAR) were 70.3% (97/138) and 15.2% (21/138), respectively. One- and 5-year patient survival were 82.1 and 60.1%, respectively, whereas the corresponding rates for death-censored graft survival were 95.6 and 93.1%. Infection was the leading cause of death (46.0% of fatal cases). The occurrence of BPAR was associated with lower 1-year patient survival [hazard ratio (HR) = 4.21, 95% confidence interval (CI) 1.64-10.82; P = 0.003]. Diabetic nephropathy was the only factor predicting 5-year death-censored graft survival (HR = 4.82, 95% CI 1.08-21.56; P = 0.040).

CONCLUSIONS

ESRD patients ≥75 years can access KT and remain dialysis free for their remaining lifespan by using grafts from extremely aged deceased donors, yielding encouraging results in terms of recipient and graft survival.

To discard or not to discard: transplantation and the art of scoring

The growing gap between inadequate supply and constantly high demand for kidney transplantation observed in the last two decades led to exploring the possibility of using organs from older donors with an increasing number of comorbidities. The main issue in this scenario is to identify transplantable organs and to allocate them to the most suitable recipients. A great number of clinical investigations proposed several acceptance/allocation criteria to reduce the discard rate of these kidneys and to improve their outcome, including histological features at the time of transplant. Despite the widespread use of several histological scoring systems, there is no consensus on their value in predicting allograft survival and there is established evidence that histological analysis is the most common reason to discard expanded criteria donor kidneys. To overcome this issue, a clinical scoring system, the Kidney Donor Profile Index (KDPI), was developed on the basis of easily accessible donor features. The KDPI score, adopted in the new US allocation procedure, has good reproducibility but presents several limitations, as suggested also in this issue of Clinical Kidney Journal. This observation should stimulate the search for novel scores combining clinical, histological and molecular features in an attempt to improve the decision process.

[Evaluation of single kidney graft outcome in patients initially programmed for a dual kidney graft transplantation]

INTRODUCTION

Kidney transplantation is championed as the gold standard treatment for patients with end-stage kidney disease. According to the biomedical agency, there is an increasing number of patients waiting for kidney transplantation. Faced with organ shortage, the use of marginal grafts may well increase the number of available kidney grafts. Occasionally, during dual kidney graft transplantation, the poor quality of one of the two grafts, or other specific circumstances, may lead to transplantation of only one of the two grafts. We have compared patient outcome concerning single kidney transplantation from an initial dual kidney graft with respect to dual kidney graft transplantation.

MATERIAL

Among 67 patients enrolled for a dual kidney graft, 39 dual kidney grafts (group 1) were compared with 12 grafts performed with only one of the two kidneys of a dual kidney graft (group 2) as well as 15 grafts performed following a classic kidney graft protocol (group 3).

RESULTS

The survival of grafts was respectively for groups 1, 2 and 3 of 100%, 72,5% and 75,4% (P=0.17). The survival of patients was respectively for groups 1, 2 and 3 of 78.3%, 89.9% and 87.8% (P=0.47).

CONCLUSION

Our study suggests that transplantation of a single kidney, initially proposed as dual kidney graft candidate, has satisfying results in terms of graft survival and patient mortality at the expense of poorer renal function in comparison to dual kidney graft. Indeed, there was no significant difference in the survival of patients and grafts. This seems promising taking into consideration that the aim of transplantation in elderly recipients is primarily to avoid dialysis, rather than having optimal post-transplantation kidney function.

LEVEL OF EVIDENCE

4.

Graft function assessment in mouse models of single- and dual-kidney transplantation

Animal models of kidney transplantation (KTX) are widely used in studying immune response of hosts to implanted grafts. Additionally, KTX can be used in generating kidney-specific knockout animal models by transplantation of kidneys from donors with global knockout of a gene to wild-type recipients or vice versa. Dual-kidney transplantation (DKT) provides a more physiological environment for recipients than single-kidney transplantation (SKT). However, DKT in mice is rare due to technical challenges. In this study, we successfully performed DKT in mice and compared the hemodynamic response and graft function with SKT. The surgical time, complications, and survival rate of DKT were not significantly different from SKT, where survival rates were above 85%. Mice with DKT showed less injury and quicker recovery with lower plasma creatinine (Pcr) and higher glomerular filtration rate (GFR) than SKT mice (Pcr = 0.34 and 0.17 mg/dl in DKT vs. 0.50 and 0.36 mg/dl in SKT at 1 and 3 days, respectively; GFR = 215 and 131 µl/min for DKT and SKT, respectively). In addition, the DKT exhibited better renal functional reserve and long-term outcome of renal graft function than SKT based on the response to acute volume expansion. In conclusion, we have successfully generated a mouse DKT model. The hemodynamic responses of DKT better mimic physiological situations with less kidney injury and better recovery than SKT because of reduced confounding factors such as single nephron hyperfiltration. We anticipate DKT in mice will provide an additional tool for evaluation of renal significance in physiology and disease.

Dual Kidney Transplantation: A Review of Past and Prospect for Future

Kidney transplantation (KT) is one of the treatment options for patients with chronic kidney disease. The number of patients waiting for kidney transplantation is growing day by day. Various strategies have been put in place to expand the donor pool. Extended criteria donors are now accepted more frequently. Increasing number of elderly donors with age > 60 years, history of diabetes or hypertension, and clinical proteinuria are accepted as donor. Dual kidney transplantation (DKT) is also more frequently done and experience with this technique is slowly building up. DKT not only helps to reduce the number of patients on waiting list but also limits unnecessary discard of viable organs. Surgical complications of DKT are comparable to single kidney transplantation (SKT). Patient and graft survivals are also promising. This review article provides a summary of evidence available in the literature.

Dual kidney transplant techniques: A systematic review

BACKGROUND

Dual kidney transplantation (DKT) was developed to improve outcomes from transplantation of extended criteria donors (ECD). This study examined which surgical techniques have been reported for DKT and whether any technique had superior patient and graft survival.

METHOD

Electronic databases were searched for published studies mapping to MESH terms: "kidney or renal" AND "transplan*" AND "dual or double." Single case reports, studies of patients less than 18 years old, studies which did not describe the surgical technique, and studies that did not report patient or graft survival were excluded.

RESULTS

Fifteen reports of 434 DKT recipients were identified. Three techniques were described: bilateral placement; unilateral placement with separate anastomoses; and unilateral placement with patch anastomoses. Patient survival across all three techniques was over 95% at 1 year, and graft survival was also similar at over 90%. Rates of delayed graft function were between 20% and 30% across all techniques.

CONCLUSION

The three techniques have equivalent delayed graft function as well as patient and graft survival rates. This is an encouraging result as it means that the surgeon can choose to use the technique which is most appropriate for their own skills and for the patient.

Zero-Time Renal Transplant Biopsies: A Comprehensive Review

Zero-time kidney biopsies, obtained at time of transplantation, are performed in many transplant centers worldwide. Decisions on kidney discard, kidney allocation, and choice of peritransplant and posttransplant treatment are sometimes based on the histological information obtained from these biopsies. This comprehensive review evaluates the practical considerations of performing zero-time biopsies, the predictive performance of zero-time histology and composite histological scores, and the clinical utility of these biopsies. The predictive performance of individual histological lesions and of composite scores for posttransplant outcome is at best moderate. No single histological lesion or composite score is sufficiently robust to be included in algorithms for kidney discard. Dual kidney transplantation has been based on histological assessment of zero-time biopsies and improves outcome in individual patients, but the waitlist effects of this strategy remain obscure. Zero-time biopsies are valuable for clinical and translational research purposes, providing insight in risk factors for posttransplant events, and as baseline for comparison with posttransplant histology. The molecular phenotype of zero-time biopsies yields novel therapeutic targets for improvement of donor selection, peritransplant management and kidney preservation. It remains however highly unclear whether the molecular expression variation in zero-time biopsies could become a better predictor for posttransplant outcome than donor/recipient baseline demographic factors.

Strategies for an Expanded Use of Kidneys From Elderly Donors

The old-for-old allocation policy used for kidney transplantation (KT) has confirmed the survival benefit compared to remaining listed on dialysis. Shortage of standard donors has stimulated the development of strategies aimed to expand acceptance criteria, particularly of kidneys from elderly donors. We have systematically reviewed the literature on those different strategies. In addition to the review of outcomes of expanded criteria donor or advanced age kidneys, we assessed the value of the Kidney Donor Profile Index policy, preimplantation biopsy, dual KT, machine perfusion and special immunosuppressive protocols. Survival and functional outcomes achieved with expanded criteria donor, high Kidney Donor Profile Index or advanced age kidneys are poorer than those with standard ones. Outcomes using advanced age brain-dead or cardiac-dead donor kidneys are similar. Preimplantation biopsies and related scores have been useful to predict function, but their applicability to transplant or refuse a kidney graft has probably been overestimated. Machine perfusion techniques have decreased delayed graft function and could improve graft survival. Investing 2 kidneys in 1 recipient does not make sense when a single KT would be enough, particularly in elderly recipients. Tailored immunosuppression when transplanting an old kidney may be useful, but no formal trials are available.Old donors constitute an enormous source of useful kidneys, but their retrieval in many countries is infrequent. The assumption of limited but precious functional expectancy for an old kidney and substantial reduction of discard rates should be generalized to mitigate these limitations.

Renal Transplantation Using Kidneys Procured From Elderly Donors Older Than 70 Years

AIM

A major problem for the transplant society is a shortage of organs for transplantation compared with the number of patients on the waiting list. This study aimed to assess the results of the transplantation of kidneys procured from older donors.

PATIENTS AND METHODS

A total of 27 kidneys procured from donors age 70 years or older were transplanted between January 1, 2010, and April 25, 2015. These represented only 4.1% of the 657 kidneys transplanted from deceased donors during this period at the same center.

RESULTS

Delayed graft function (DGF) in the recipients of kidneys procured from donors age 70 or older occurred in 46.1% of patients, whereas the recipients of kidneys from younger donors showed DGF at a frequency of 32.7% (P = NS). The annual and 3-year survival rates of kidneys in the study group were 85% and 80%, respectively, and in the control group were 92.5% and 88.6%, respectively (P = NS). According to the Polish National Organ Procurement Organization (Poltransplant), the annual survival rate of a transplanted kidney in Poland stands at 89%, whereas the 3-year survival rate is 82%. We detected no significant posttransplantation differences in the serum creatinine concentration and in the estimated glomerular filtration rate between the study and control groups. The donor age and donor creatinine were the variables independently associated with DGF.

CONCLUSIONS

The results of transplantation of kidneys from elderly donors were comparable to those of transplantation from younger donors. Kidneys harvested from elderly donors should be used for a transplant after a preliminary assessment.

Survival Benefit From Kidney Transplantation Using Kidneys From Deceased Donors Aged ≥75 Years: A Time-Dependent Analysis

Patients with end-stage renal disease have longer survival after kidney transplantation than they would by remaining on dialysis; however, outcome with kidneys from donors aged ≥75 years and the survival of recipients of these organs compared with their dialysis counterparts with the same probability of obtaining an organ is unknown. In a longitudinal mortality study, 2040 patients on dialysis were placed on a waiting list, and 389 of them received a first transplant from a deceased donor aged ≥75 years. The adjusted risk of death and survival were calculated by non-proportional hazards analysis with being transplanted as a time-dependent effect. Projected years of life since placement on the waiting list was almost twofold higher for transplanted patients. Nonproportional adjusted risk of death after transplantation was 0.44 (95% confidence interval [CI] 0.61-0.32; p < 0.001) in comparison with those that remained on dialysis. Stratifying by age, adjusted hazard ratios for death were 0.17 (95% CI 0.47-0.06; p = 0.001) for those aged <65 years, 0.56 (95% CI 0.92-0.34; p = 0.022) for those aged 65-69 years and 0.82 (95% CI 1.28-0.52; p = 0.389) for those aged ≥70 years. Although kidney transplantation from elderly deceased donors is associated with reduced graft survival, transplanted patients have lower mortality than those remaining on dialysis.

The Kidney Donor Profile Index (KDPI) of marginal donors allocated by standardized pretransplant donor biopsy assessment: distribution and association with graft outcomes

Pretransplant donor biopsy (PTDB)-based marginal donor allocation systems to single or dual renal transplantation could increase the use of organs with Kidney Donor Profile Index (KDPI) in the highest range (e.g. >80 or >90), whose discard rate approximates 50% in the United States. To test this hypothesis, we retrospectively calculated the KDPI and analyzed the outcomes of 442 marginal kidney transplants (340 single transplants: 278 with a PTDB Remuzzi score<4 [median KDPI: 87; interquartile range (IQR): 78-94] and 62 with a score=4 [median KDPI: 87; IQR: 76-93]; 102 dual transplants [median KDPI: 93; IQR: 86-96]) and 248 single standard transplant controls (median KDPI: 36; IQR: 18-51). PTDB-based allocation of marginal grafts led to a limited discard rate of 15% for kidneys with KDPI of 80-90 and of 37% for kidneys with a KDPI of 91-100. Although 1-year estimated GFRs were significantly lower in recipients of marginal kidneys (-9.3, -17.9 and -18.8 mL/min, for dual transplants, single kidneys with PTDB score<4 and =4, respectively; p<0.001), graft survival (median follow-up 3.3 years) was similar between marginal and standard kidney transplants (hazard ratio: 1.20 [95% confidence interval: 0.80-1.79; p=0.38]). In conclusion, PTDB-based allocation allows the safe transplantation of kidneys with KDPI in the highest range that may otherwise be discarded.

Spanish consensus document for acceptance and rejection of kidneys from expanded criteria donors

In the recent years, more than 60% of available deceased donors are either older than 50 yr or have significant vascular comorbidities. This makes the acceptance and rejection criteria of renal allografts very rigorous, especially in cases of younger recipients, and at the same time encourages live donations. In our country, there is a lack of homogeneity in the percentages of use of expanded criteria donor (ECD) allografts between the different autonomous communities. Furthermore, the criteria vary greatly, and in some cases, great importance is given to the biopsy while in others very little. In this study, we present a unified and homogenous criteria agreed upon by consensus of a 10-member Panel representing major scientific societies related to renal transplantation in Spain. The criteria are to be used in accepting and/or rejecting kidneys from the so-called ECDs. The goal was to standardize the use of these organs, to optimize the results, and most importantly to provide for the maximum well being of our patients. Finally, we believe that after taking into account the Panel's thorough review of specific scientific literature, this document will be adaptable to other national renal transplant programmes.

Association of early kidney allograft failure with preformed IgA antibodies to β2-glycoprotein I

In the current immunosuppressive therapy era, vessel thrombosis is the most common cause of early graft loss after renal transplantation. The prevalence of IgA anti-β2-glycoprotein I antibodies (IgA-aB2GPI-ab) in patients on dialysis is elevated (>30%), and these antibodies correlate with mortality and cardiovascular morbidity. To evaluate the effect of IgA-aB2GPI-ab in patients with transplants, we followed all patients transplanted from 2000 to 2002 in the Hospital 12 de Octubre prospectively for 10 years. Presence of IgA-aB2GPI-ab in pretransplant serum was examined retrospectively. Of 269 patients, 89 patients were positive for IgA-aB2GPI-ab (33%; group 1), and the remaining patients were negative (67%; group 2). Graft loss at 6 months post-transplant was significantly higher in group 1 (10 of 89 versus 3 of 180 patients in group 2; P=0.002). The most frequent cause of graft loss was thrombosis of the vessels, which was observed only in group 1 (8 of 10 versus 0 of 3 patients in group 2; P=0.04). Multivariate analysis showed that the presence of IgA-aB2GPI-ab was an independent risk factor for early graft loss (P=0.04) and delayed graft function (P=0.04). There were no significant differences regarding patient survival between the two groups. Graft survival was similar in both groups after 6 months. In conclusion, patients with pretransplant IgA-aB2GPI-ab have a high risk of early graft loss caused by thrombosis and a high risk of delayed graft function. Therefore, pretransplant IgA-aB2GPI-ab may have a detrimental effect on early clinical outcomes after renal transplantation.

Dual kidney transplant: a single-center experience and review of the literature

OBJECTIVES

Adult dual kidney transplant is a strategy to overcome the imbalance between limited nephron mass supplied from an older donor and a recipient with a metabolic request.

MATERIALS AND METHODS

In our report, we review the literature and present our single-center experience. From June 2007 until July 2012, nine hundred twenty-eight single and seventeen dual kidney transplants from deceased donors were performed.

RESULTS

The average donor was 71.5 ± 3.6 years of age with an average serum creatinine, creatinine clearance, and an average number of sclerotic glomeruli, 106.1 ± 44.2 μmol/L, 0.97 ± 0.37 mL/s, and 22.4 ± 14.2. Immediate graft function and acute rejection episodes were observed in 75% and 6% of patients. The overall patient survival rates at 1 and 2 years after transplant were 93%. The overall graft survival rates at 1 and 2 years were 88%.

CONCLUSIONS

Previous studies and our single-center experience suggest that the dual transplant procedure may help improve results of kidney transplants from expanded criteria donors and extend the donor pool by using kidneys that would be discarded otherwise.

Impact of the pre-transplant histological score on 3-year graft outcomes of kidneys from marginal donors: a single-centre study

BACKGROUND

The reliability of kidney biopsy as the sole means for assessing kidneys from extended-criteria donors (ECDs) to be allocated to single or dual transplantation is still a matter of debate.

METHODS

We compared retrospectively 3 years graft survival and renal function in 44 recipients of a single kidney graft from a marginal donor with good renal function and a Karpinski histological score of ≤ 3 and 56 recipients of a single transplant with a Karpinski score of 4 or 5. The donors' and recipients' characteristics were compared by means of Wilcoxon's rank-sum test and Fisher's exact test, and survival was analysed using the log-rank test and Cox regression survival analysis.

RESULTS

The donors with the worse histological scores were slightly younger (68.0 ± 4.74 versus 71.3 ± 4.6 years, P < 0.01) and had a higher glomerular filtration rate (85.8 ± 28.2 versus 76.3 ± 26.53 mL/min, P = 0.013), but there was no difference in serum creatinine levels (0.83 ± 0.24 versus 0.85 ± 0.30 mg/dL, P = 0.381). Three years after transplantation, there was no difference between the two groups in terms of recipient serum creatinine levels (1.94 ± 0.69 versus 1.74 ± 0.49 mg/dL, P = 0.134), estimated glomerular filtration rate (eGFR, 45.6 ± 21.1 versus 51.7 ± 22.0 mL/min, P = 0.331) or the rates of graft loss (27.3 versus 35.7%, P = 0.47), delayed graft function or acute rejection.

CONCLUSIONS

In our experience, provided the donor has a normal renal function, a difference in the pre-transplant histological score of kidneys from marginal cadaveric donors do not have a significant influence on the outcome 3 years after transplantation. Our findings might represent a basis for designing a randomized controlled trial of using a higher histological score threshold for the DKT allocation of grafts from ECDs with a normal renal function.

Long-term results of biopsy-guided selection and allocation of kidneys from older donors in older recipients

In our old-for-old program, we discard or allocate older extended criteria donor kidneys to single (SKT) or dual kidney transplantation (DKT) depending on histological Remuzzi's score in recipients older than 60 years. Here, we analyze the long-term results of this program and try to identify independent predictors of patient and graft survival. Between December 1996 and January 2008, we performed 115 SKT and 88 DKT. Discard rate was 15%. Acute rejection incidence was higher in SKT than in DKT (22.6% vs. 11.4%, p = 0.04). Renal function was better in DKT than in SKT up to 5 years after transplantation. Surgical complications were frequent in DKT. Ten-year cumulative graft survival was significantly lower in the SKT group (31% vs. 53%, p = 0.03). In SKT, histological score 4 provided similar graft survival than 3 or less, whereas in DKT score 4, 5 or 6 displayed similar outcome. Finally, independent predictors of graft survival were history of major adverse cardiac event and 1-year serum creatinine, rather than SKT or DKT. In conclusion, this biopsy-guided old-for-old strategy resulted in acceptable long-term graft survival. Our results suggest that DKT should be considered for scores of 5 or 6 only.

Ultrasound findings in dual kidney transplantation

PURPOSE

This study was done to analyse colour Doppler ultrasound (CDUS) findings in patients with dual kidney transplantation (DKT) and to compare renal volume and resistive index (RI) values between DKT and single kidney transplantation (SKT).

MATERIALS AND METHODS

We reviewed the clinical and imaging findings [30 CDUS, five magnetic resonance (MR) and one computed tomography (CT) examination] in 30 patients with DKT (23 men and seven women; median age 65 years; range 55-82). Three patients had clinical signs of graft malfunction. Renal volumes and RI were compared with those of 14 SKT patients and comparable levels of renal function.

RESULTS

Three patients had graft dysfunction: one had chronic rejection and two had pathologies involving one kidney only (one encrusted pyeloureteritis of a left graft and one occluded main artery of a left graft). Asymptomatic unilateral pathologies were seen in six cases. In asymptomatic DKT patients, no significant differences in length, volume, cortical echogenicity and RI between the two kidneys were observed; DKTs were smaller (median volume 116.7 vs. 171.6 cc) and had higher RIs (0.76 vs. 0.68) (p<0.01) than SKTs.

CONCLUSIONS

CDUS provides useful information in patients with DKT, allowing detection of clinically unsuspected unilateral diseases. At comparable levels of renal function, DKT patients had higher RI and lower volumes than SKT patients.

Single-center experience with kidney transplantation using deceased donors older than 75 years

BACKGROUND

Use of kidneys from donors aged 75 years and older is controversial. The purpose of this study was to evaluate the outcome of kidney transplantation (KT) involving these expanded criteria donors.

MATERIALS AND METHODS

From January 2001 to November 2009, 52 patients were transplanted with grafts from deceased donors aged 75 years and older. Donor and recipient data and intra- and postoperative variables were analyzed by univariate and multivariate regression analyses. Graft and patient survival were calculated using the Kaplan-Meier method.

RESULTS

Forty-one single and 11 double KTs were performed. Median recipient age was 66 years. After a median follow-up of 30 months, 37 of 52 patients are alive, 30 with functioning grafts (81%). Graft and patient survival rates at 3 and 5 years are 63% and 53%, and 78% and 64%, respectively. Double KT was significant predictor for graft survival by multivariate analysis. Five-year graft survival for single and double KT was 41% and 90%, respectively (P=0.0394). Comorbidity Index, hospital stay, acute rejection reaction, re-KT, and induction immunosuppressive therapy with interleukin-2 were significant predictors for patient survival by univariate analysis. Hospital stay and induction immunosuppression therapy reached multivariate significance. Double KT, cold ischemia time, and Comorbidity Index were found potential predictors of delayed graft function in our series.

CONCLUSIONS

Fairly good long-term outcome of KT from donors aged 75 years and older can be achieved in elderly recipients with low comorbidities when dual kidney grafting is used and when re-transplantations and high grade surgical complications are avoided.

Illinois statewide dual kidney transplantation experience--are we appropriately selecting kidneys?

PURPOSE

Dual kidney transplantation is a technique that some transplant centers have adopted to increase organ use. We investigated whether kidneys that were recovered and discarded were similar to those kidneys used for dual kidney transplantation.

MATERIALS AND METHODS

We reviewed all kidneys recovered, biopsied and placed on machine perfusion in the state of Illinois from January 2002 to October 2009. We selected those kidneys used in dual kidney transplant, and compared their characteristics to those of kidneys that were recovered and biopsied but ultimately discarded. The immediate and 1-year outcomes of the dual kidney transplant recipients were analyzed.

RESULTS

During the study period 60 dual transplants were performed while 94 kidney pairs were discarded. Overall donors from the used group had a lower mean creatinine clearance, older mean patient age, lower percentage of glomerulosclerosis, higher final flow rate and lower resistance. However, the comparison between those kidneys used successfully with 1-year graft survival and those discarded demonstrated only 3 less favorable parameters among the discarded group, namely a higher percentage of glomerulosclerosis (18.5% vs 13.9%, p=0.024), a higher degree of interstitial fibrosis and a higher final resistance (0.39 vs 0.31, p<0.001).

CONCLUSIONS

The considerable overlap in demographics, histology and perfusion parameters between used and discarded kidneys suggests that many kidneys that were recovered and discarded could have been used in dual kidney transplantation with acceptable outcomes. This highlights the need for further study of how kidneys are selected and used.

Dual-kidney transplants as an alternative for very marginal donors: long-term follow-up in 63 patients

BACKGROUND

Organ shortage has led to the use of dual-kidney transplant (DKT) of very marginal donors into a single recipient to increase the use of marginal organs. To date, few data are available about the long-term outcome of DKT and its usefulness to increase the pool of available organ.

METHODS

We conducted a single-center cohort study of DKTs with longitudinal follow-up over an 8-year period. Between 1999 and 2007, 63 DKTs were performed. All kidneys from donors younger than 75 years refused by all centers for single transplantation, and kidneys from donors aged 75 years or older were routinely evaluated based on preimplantation glomerulosclerosis. Renal function, patient or graft survival, and perioperative complications were compared with 66 single kidneys from expanded criteria donors (ECD) and 63 ideal kidney donors.

RESULTS

After a median follow-up of 56 months, patient or graft survival was similar between the three groups. Twelve-, 36-, and 84-month creatinine clearance were similar for DKT and ECD (12 months: 58 and 59 mL/min; 36 months: 54 and 60 mL/min; and 84 months: 62 and 51 mL/min, respectively). For the study period, the routine evaluation of very marginal kidneys for DKT in our center has led to an increase of 47% in the transplants from donors aged 50 years or older, which represent 12% at the level of our organ procurement organization.

CONCLUSIONS

DKT patients can expect long-term results comparable with single kidney ECD. The implementation of a DKT program in our unit safely increased the pool of organs from marginal donors.

Significance of preimplantation analysis of kidney biopsies from expanded criteria donors in long-term outcome

BACKGROUND

The shortage of organs has led to expanding the criteria for donors. Histologic evaluations before transplantation may enable the identification of organs unsuitable for single implantation. The aim of this study was to evaluate the histologic findings as prognostic factors of allograft survival from expanded criteria donors (ECDs).

METHODS

We included a cohort of 136 single transplantations with kidneys from ECD and correlated the preimplantation pathologic findings with graft failure. Renal structures from ECD older (n=104) or younger (n=32) than 60 years were evaluated histologically for renal senescence and rated with a total histologic score. A multivariate Cox analysis was performed to identify predictors of graft failure.

RESULTS

Glomerulosclerosis was the most prevalent lesion in biopsies from donors older and younger than 60 years (P=0.002); interstitial fibrosis was more severe in biopsies from older donors (P=0.001); older donors showed a higher prevalence of tubular atrophy (P=0.022), and vascular compartment showed no significant differences. Kidney biopsy-based scoring system ranged from 0 to 15 points, indicating the presence of changes in the renal parenchyma. Biopsies with total histologic scores less than or equal to 5 showed significantly better 5-year graft survival than those with scores more than 5 (P<0.001). A preimplantation score more than 5 points remained an independent predictor of graft failure (hazard ratio 6.95; 95% confidence interval 1.57-30).

CONCLUSIONS

Histologic analysis of kidney biopsies before transplantation is a valuable tool for facilitating the selection of viable grafts from ECD donors. When the total score is more than 5, single kidney transplantation from ECD should not be recommended for patients similar to this study population.

Deceased donor organ transplantation with expanded criteria donors: a single-center experience from India

INTRODUCTION

Deceased donor organ transplantation (DDOT) accounts for <4% of renal transplants in India. Many volunteers come forth for organ donation with increasing awareness; unfortunately, the majority are marginal donors, but their rejection would hamper the DDOT program. Judicious use of marginal organs is a challenge for developing countries.

PATIENTS AND METHODS

We performed 29 renal transplants from 21 expanded criteria donors (ECD) out of 115 DDOT between January 2006 to April 2009-10 dual (DKT) and 19 single (SKT). Fourteen donors had hypertension, a cerebrovascular accident as the cause of death, 9 had both, and 4 had diabetes. Mean donor age was 70.3 +/- 8.9 years. Decisions on the procedure were based upon frozen section biopsy in 13 of 21 donors. Mean DKT donor age was 76 +/- 9.7 years versu 64 +/- 5.7 years of SKT donors. The native kidney diseases were chronic glomerulonephritis (n = 14), diabetic nephropathy (n = 7), tubulointerstitial nephritis (n = 4) and polycystic kidney disease, focal segmental glomerulosclerosis, lupus nephritis and patchy cortical necrosis, (n = 1 each). Mean recipient age of DKT versus SKT was 43.5 versus 42.3 years. All recipients received rabbit anti-thymocyte globulin, followed by steroid, mycophenolate mofetil/calcinueurin inhibitor.

RESULTS

Over a mean follow-up of 341 days, the mean serum creatinine (SCr) of 25/29 patients was 1.60 mg/dL (range, 1.0-2.6). The mean SCr of SKT patients was 1.59 +/- 0.63 mg/dL and of DKT, 1.62 +/- 0.48 mg/dL. Ten patients had delayed graft function and 11 had biopsy proven acute tubular necrosis. Seven (24%) patients had rejection (grade 3 Banff update '05, type IA; 4, type 2A); 6 responded to antirejection; 1 graft was lost at 7 months due to chronic rejection. Three (10.3%) patients were lost, 1 each due to AMI, sepsis, and CMV disease.

CONCLUSION

In the circumstances of organ shortage, DDOT with expanded criteria donor is a feasible option.

Renal allografts from donors older than 70 years are useful for single transplantation

Kidney transplantation has been related in elderly recipients to a greater longevity compared with dialysis. Due to the scarcity of donors, transplantation of older patients depends on the acceptance of older donors. We compared the characteristics and evolution of transplants from donors >or=70 years (n = 53) with those from donors >55-<70 years (n = 201). Group D >or=70 included older recipients (65.37 +/- 4.9 vs 55.92 +/- 9.66 years; P = .000) and more women (62.3% vs 45.3%; P = .02), with more peripheral arterial disease (10.9% vs 2.4%; P = .011). No differences in donor characteristics were observed. Induction treatment with thymoglobulin or basiliximab was more common in D >or=70 (81.1% vs 57.3%; P = .006), with no differences in other immunosuppressive drugs. The incidence of delayed graft function (DGF) was similar (P = .82), with a trend to a lower incidence of acute rejection episodes among D>or=70 (11.8% vs 22.5%; P = 0.09). Serum creatinine and proteinuria levels did not differ during follow-up (P > .05). Patients in D >or=70 displayed more episodes of urinary sepsis (19.1% vs 6.4%; P = .008), but no differences were observed in cytomegalovirus (CMV) infection (P = .629), neoplasia (P = .118), ischemic cardiopathy (P = .642), or hospital readmission due to infections (P = .567). Graft survivals at 5 years were 70% and 75% (P = .279) among groups D >or=70 and D>55-<70, respectively, and patient survivals at 5 years were 88% and 88% (P = .63), respectively. In conclusion, our study showed that selected kidneys from donors older than 70 years were followed with excellent graft and patient survivals, permitting older patients on renal replacement therapy to benefit from renal transplantation.

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.

Dual kidney transplantation with organs from extended criteria cadaveric donors

PURPOSE

The critical shortage of kidneys available for transplantation has led to alternate strategies to expand the pool. Transplantation of the 2 kidneys into a single recipient using organs suboptimal for single kidney transplantation was suggested. We assessed results in 24 grafts allocated for dual kidney transplantation vs those in a control group of 44 designated for single kidney transplantation. Each group underwent pretransplant biopsy and recipients were age matched.

MATERIALS AND METHODS

Dual kidney transplantation was done in 24 of 1,091 transplants (2.1%) from 2001 to 2008. In patients with dual kidney transplant vs single kidney transplant mean recipient age was 60.6 vs 60.8 years, mean HLA-A, B and DR mismatches were 3.3 vs 2.9, and average patient waiting time was 15.6 vs 13.9 months. All grafts were perfused with University of Wisconsin solution with a mean cold ischemia time of 17.9 hours. On donor dual kidney biopsy in the dual kidney transplant vs single kidney transplant group the average fibrosis rate was 30% (range 25% to 45%) vs 25% (range 3% to 40%) and the glomerulosclerosis rate was 17.9% (range 3.2% to 40.7%) vs 7.1% (range 0% to 50%).

RESULTS

Good postoperative renal function was noted in 14 dual kidney transplantation cases. Acute tubular necrosis requiring dialysis developed in 5 patients as well as acute rejection in 1. Two dual kidney recipients (8%) died in the postoperative period with no single kidney deaths. One patient underwent bilateral transplantectomy. Mean anesthesia time was longer in the dual group (371 vs 212 minutes). Patient and graft survival was equivalent to that in the control group at 36 months.

CONCLUSIONS

Careful selection of marginal kidneys based on clinical and histological criteria allows the use of organs that would not ordinarily be sufficient for transplantation with acceptable outcomes. This is a valid strategy to address the organ shortage.