Factors related to the donor organ are major determinants of renal allograft function and survival

Transplant and Recipient Factors in Prediction of Kidney Transplant Outcomes: A UK-Wide Paired Analysis

Background: In kidney transplantation, the relative contribution of various donor, procedure and recipient-related factors on clinical outcomes is unknown. Previous paired studies have largely focused on examining factors predicting early outcomes, where the effect of donor factors is thought to be most important. Here, we sought to examine the relationship between early and long-term outcomes in a UK-wide paired kidney analysis. Methods: UK Transplant Registry data covering 24,090 kidney transplants performed between 2001–2018, where both kidneys from each donor were transplanted, were analysed. Case-control studies were constructed using matched pairs of kidneys from the same donor discordant for outcome, to delineate the impact of transplant and recipient factors on longer-term outcomes. Results: Multivariable conditional logistic regression identified HLA mismatch as an important predictor of prolonged delayed graft function (DGF), in the context of a paired study controlling for the influence of donor factors, even when adjusting for early acute rejection. Prolonged DGF, but not human leucocyte antigen (HLA) mismatch, strongly predicted 12-month graft function, and impaired 12-month graft function was associated with an increased risk of graft failure. Conclusions: This study indicates prolonged DGF is associated with adverse long-term outcomes and suggests that alloimmunity may contribute to prolonged DGF by a mechanism distinct from typical early acute rejection.

Kidney-intrinsic factors determine the severity of ischemia/reperfusion injury in a mouse model of delayed graft function

Delayed graft function due to transplant ischemia/reperfusion injury adversely affects up to 50% of deceased-donor kidney transplant recipients. However, key factors contributing to the severity of ischemia/reperfusion injury remain unclear. Here, using a clinically relevant mouse model of delayed graft function, we demonstrated that donor genetic background and kidney-intrinsic MyD88/Trif-dependent innate immunity were key determinants of delayed graft function. Functional deterioration of kidney grafts directly corresponded with the duration of cold ischemia time. The graft dysfunction became irreversible after cold ischemia time exceeded six hours. When cold ischemia time reached four hours, kidney grafts displayed histological features reflective of delayed graft function seen in clinical kidney transplantation. Notably, kidneys of B6 mice exhibited significantly more severe histological and functional impairment than kidneys of C3H or BALB/c mice, regardless of recipient strains or alloreactivities. Furthermore, allografts of B6 mice also showed an upregulation of IL-6, neutrophil gelatinase-associated lipocalin, and endoplasmic reticulum stress genes, as well as an increased influx of host neutrophils and memory CD8 T-cells. In contrast, donor MyD88/Trif deficiency inhibited neutrophil influx and decreased the expression of IL-6 and endoplasmic reticulum stress genes, along with improved graft function and prolonged allograft survival. Thus, kidney-intrinsic factors involving genetic characteristics and innate immunity serve as critical determinants of the severity of delayed graft function. This preclinical murine model allows for further investigations of the mechanisms underlying delayed graft function.

Xenotransplantation: Progress Along Paths Uncertain from Models to Application

For more than a century, transplantation of tissues and organs from animals into man, xenotransplantation, has been viewed as a potential way to treat disease. Ironically, interest in xenotransplantation was fueled especially by successful application of allotransplantation, that is, transplantation of human tissue and organs, as a treatment for a variety of diseases, especially organ failure because scarcity of human tissues limited allotransplantation to a fraction of those who could benefit. In principle, use of animals such as pigs as a source of transplants would allow transplantation to exert a vastly greater impact than allotransplantation on medicine and public health. However, biological barriers to xenotransplantation, including immunity of the recipient, incompatibility of biological systems, and transmission of novel infectious agents, are believed to exceed the barriers to allotransplantation and presently to hinder clinical applications. One way potentially to address the barriers to xenotransplantation is by genetic engineering animal sources. The last 2 decades have brought progressive advances in approaches that can be applied to genetic modification of large animals. Application of these approaches to genetic engineering of pigs has contributed to dramatic improvement in the outcome of experimental xenografts in nonhuman primates and have encouraged the development of a new type of xenograft, a reverse xenograft, in which human stem cells are introduced into pigs under conditions that support differentiation and expansion into functional tissues and potentially organs. These advances make it appropriate to consider the potential limitation of genetic engineering and of current models for advancing the clinical applications of xenotransplantation and reverse xenotransplantation.

Analysis of Pre-transplant Resuscitation Factors Influencing Immediate Graft Function After Deceased Donor Kidney Transplantation

BACKGROUND

The management of a deceased donor in the intensive care unit before organ transplantation is important for the outcome of the recipient. Herein, we analyze the pre-transplant resuscitation factors managed before procurement that could influence graft function immediately after deceased-donor kidney transplantation (DDKT).

METHODS

A total of 271 DDKTs performed at Seoul St. Mary's Hospital, Korea, from January 2009 to March 2016 were reviewed. We divided the patients into a delayed graft function (DGF) group and a non-DGF group, and compared postoperative outcomes between the 2 groups. We also analyzed the predisposing factors of DGF using multivariate analysis.

RESULTS

A total of 36 cases developed DGF while 235 patients did not, and the demographic characteristics of the recipients in the two groups had no significant difference. Of the pre-transplant resuscitation factors, preoperative polyuria, the maximal levels of serum sodium and BUN, and transfer times were significantly higher in the DGF group (P < .001). In a multivariable analysis, preoperative polyuria (odds ratio 4.835, P = .036), elevated preoperative level of sodium (odds ratio 1.227, P = .001), and extended transfer times (odds ratio 1.001, P < .001) were the independent risk factors of the donor in pre-transplant resuscitation management associated with DGF.

CONCLUSIONS

Polyuria, high levels of sodium before procurement, and prolonged transfer times are independent risk factors for DGF after a DDKT. Active intervention and early implementation of the intensivist can help in managing these factors effectively and thus ultimately improve graft function.

Accommodation in ABO-incompatible organ transplants

Accommodation refers to a condition in which a transplant (or any tissue) appears to resist immune-mediated injury and loss of function. Accommodation was discovered and has been explored most thoroughly in ABO-incompatible kidney transplantation. In this setting, kidney transplants bearing blood group A or B antigens often are found to function normally in recipients who lack and hence produce antibodies directed against the corresponding antigens. Whether accommodation is owed to changes in anti-blood group antibodies, changes in antigen or a change in the response of the transplant to antibody binding are critically reviewed and a new working model that allows for the kinetics of development of accommodation is put forth. Regardless of how accommodation develops, observations on the fate of ABO-incompatible transplants offer lessons applicable more broadly in transplantation and in other fields.

Influence of antithymocyte globulin treatment of brain-dead organ donor on inflammatory response in cardiac grafts: an experimental study in mice

The expression of proinflammatory cytokines in donor hearts after antithymocyte globulin (ATG) treatment given prior to organ removal was evaluated to analyze changes in inflammatory response. Adult female OF-1 mice were randomized into brain death (BD) groups (BD Control, BD ATG) with or without treatment, and Controls (Control, ATG). BD induction was performed through gradual inflation of an intracranial positioned balloon catheter. At the end of a 6-h observation period, ATG (1 mg/kg BW) was given intravenously. After 45 min, the donor hearts were removed. Proinflammatory markers IL-2 and IL-6 were examined using ELISA and immunohistochemistry staining. After single administration of ATG, the inflammatory reaction in the myocardium showed a significant reduction in IL-2 expression (BD Control vs. BD ATG, P = 0.033). Our investigation showed expected increase in proinflammatory mediators after BD. This increase was abolished by single infusion of ATG, indicated by significant reduction in IL-2 levels in the myocardium. We observed a reduction of IL-6 deposition in media cells in ATG-treated specimens. Further research is necessary to evaluate the role of ATG in donor management considering a potentially positive effect of ATG on IL-2-directed inflammatory response and possible reduction of IL-6-mediated vascular changes.

Variables during Care of Adult Donors That Can Influence Outcomes of Kidney Transplantation

Publications that relate characteristics of donors to renal function of recipients are reviewed. Most publications report retrospective observations that relate outcomes to donor variables that cannot be altered during donor care. Factors that can be altered in adult donors in an effort to improve recipients' outcomes include urine output and creatinine level. Increasing urine output to more than 100 mL/h, at least during the hour before explantation, and returning the creatinine level to match its serum concentration when the patient was admitted can improve outcomes. Ways of accomplishing those goals during donor care are discussed, with emphasis on support of renal blood flow.

Kidney Graft Survival in Italy and Factors Influencing it

Purpose

National registry data are often a suitable basis for examination of transplant outcomes. Using data supplied by the Italian National Transplant Registry, established in 1995, we performed the first nationwide analysis of this kind.

Methods

A retrospective analysis of 4893 recipients of cadaveric kidneys transplanted in all Italian centers from 1995 through 2000 was done to study 5-year graft survival. The association between some donor and recipient variables and outcomes in renal transplantation was analyzed. Graft survival was 93% at 3 months, 89% at 1 year, 82% at 3 years, and 80% at 5 years after transplantation.

Results

A significant association between graft survival and donor age (old vs young, relative risk [RR] = 1.62, 95% CI 1.27–2.06) and recipient age (old vs young, RR = 1.25, 95% CI 1.02–1.53). Graft survival was also associated with cold ischemia time (24–36 hours, RR=1.39, 95% CI 1.05–1.85 and >36 hours, RR=1.94, 95% CI 1.32–2.86 vs 0–24 hours) and donor/recipient sex mismatch (female/male vs male/male, RR=1.50, 95% CI 1.17–1.93).

Conclusion

The quality of kidney transplantation in Italy is satisfactory and is comparable to that in other developed countries. Furthermore, our experience confirms that both donor and recipient factors are major determinants of renal allograft function.

Donor Kidney Evaluation

In patients with end-stage renal disease, kidney transplantation is the best means to extend survival and offer a better quality of life. The current shortage of organs available for transplantation has led to an effort to expand the kidney donor pool, including the use of nonideal donor kidneys. Assessment of the quality of the donated kidney is essential, and would facilitate the decision to transplant a potential organ or discard it. Multiple clinical and histologic parameters have been examined to evaluate the donor kidney and relate the findings to the graft outcome, but clear-cut criteria are yet to be defined.

Predictive model for the optimal glomerular filtration rate in living kidney transplant recipients

BACKGROUND

Recipient glomerular filtration rate (GFR) after living kidney transplantation (KT) is influenced by many factors. Defining the appropriate level of recipient GFR post-KT is helpful. The aim of this study was to establish a predictive model to estimate the optimal recipient GFR at 1 week post-KT.

METHODS

We retrospectively analyzed 211 living KTs without delayed or slow graft function. Estimated GFR was calculated using the Cockcroft-Gault (CG) formula. Donor kidney volume was obtained from routine computed tomographic angiography (CTA) by work station GE (AW 4.20) program. Multivariate analysis was carried out with automated backward selection to establish the predictive model. The bias, precision, and accuracy of our model were also determined by application of the model to another 37 living KTs.

RESULTS

In multivariate analysis, the significant parameters to predict recipient GFR were donor age (P = .025) and kidney volume (P < .0001) and both were incorporated in the predictive model; predicted CG recipient GFR = 28.325 + (donor kidney volume x 0.282) - (0.297 x donor age). The correlation coefficient (R) is 0.5. Application to another group revealed that our model had high precision (14.45 mL/min), small positive bias (0.24 mL/min), and high percentage (81%) of predicted value, which was within 30% of the observed recipient GFR post-KT.

CONCLUSION

Our predictive model included donor age and donor kidney volume and could be used to estimate the optimal recipient GFR post-KT. This could be helpful to identify early graft dysfunction and to make a decision if further invasive investigation such as allograft biopsy is necessary.

Effects of cellular sensitization and donor age on acute rejection and graft function after deceased-donor kidney transplantation

BACKGROUND

Allografts from older donors may be more immunogenic than those from younger donors. Pretransplantation cellular sensitization may interact with advanced donor age to increase the risk of immune injury after deceased-donor kidney transplantation.

METHODS

The outcomes of 118 consecutive deceased-donor kidney transplant recipients with available pretransplantation donor-stimulated enzyme-linked immunosorbent spot (ELISPOT) assays for interferon gamma were analyzed retrospectively to determine the impact of cellular sensitization and other clinical variables, including donor age, on the incidence of acute rejection (AR) in the first year after deceased-donor transplantation and on estimated glomerular filtration rate 12 months after transplantation.

RESULTS

The incidence of AR was higher in patients with positive pretransplantation ELISPOT assays versus those with negative assays (36% vs. 14%, P=0.009). Logistic regression indicated that the combination of donor age 50 years or older and a positive pretransplantation ELISPOT assay was more strongly associated with AR (odds ratio, 12.1; confidence interval, 1.1-133) than either variable alone. Estimated glomerular filtration 12 months after transplantation was highest in ELISPOT-negative patients receiving kidneys from donors younger than 50 years and lowest in ELISPOT-positive recipients with donors 50 years or older.

CONCLUSION

The combination of advanced donor age and pretransplantation cellular sensitization increases the risk of AR and poor graft function after deceased-donor kidney transplantation beyond the risk associated with each factor alone.

Predisposing factors of diminished survival in simultaneous liver/kidney transplantation

Since the adoption of the Model for End-Stage Liver Disease, simultaneous liver/kidney transplants (SLKT) have substantially increased. Recently, unfavorable outcomes have been reported yet contributing factors remain unclear. We retrospectively reviewed 74 consecutive adult SLKT performed at our center from 2000 to 2010 and compared with kidney transplant alone (KTA, N = 544). In SLKT, patient and death-censored kidney graft survival rates were 64 ± 6% and 81 ± 5% at 5 years, respectively (median follow-up, 47 months). Multivariable analyses revealed three independent risk factors affecting patient survival: hepatitis C virus positive (HCV+, hazard ratio [HR] 2.9, 95% confidence interval [CI] 1.1-7.9), panel reactive antibody (PRA) > 20% (HR 2.8, 95% CI 1.1-7.2) and female donor gender (HR 2.9, 95% CI 1.1-7.9). For death-censored kidney graft survival, delayed graft function was the strongest negative predictor (HR 8.3, 95% CI 2.5-27.9), followed by HCV+ and PRA > 20%. The adjusted risk of death-censored kidney graft loss in HCV+ SLKT patients was 5.8 (95% CI 1.6-21.6) compared with HCV+ KTA (p = 0.008). Recurrent HCV within 1 year after SLKT correlated with early kidney graft failure (p = 0.004). Careful donor/recipient selection and innovative approaches for HCV+ SLKT patients are critical to further improve long-term outcomes.

Donor age and ABCB1 1199G>A genetic polymorphism are independent factors affecting long-term renal function after kidney transplantation

BACKGROUND

In renal tubular cells, cytochrome P4503A enzyme and adenosine triphosphate-binding cassette transporter activities result in intracellular drug or metabolite exposure variability, depending on genetic polymorphisms. Our aim was to establish whether long-term renal function is affected by genetic polymorphisms in biotransformation enzymes and drug transporters of the donor after kidney transplantation.

MATERIALS AND METHODS

The study was conducted in a selected cohort of 97 kidney recipients. Genotyping of donors was performed on renal biopsy samples obtained before transplantation. Serum creatinine levels and Cockcroft-Gault estimated glomerular filtration rate were considered 1 y after transplantation and at the last follow-up.

RESULTS

Long-term function was significantly better in recipients of an organ from donors carrying the ABCB1 1199A mutated allele (median and range creatinine values were 1.1 mg/dL [0.8-1.5mg/dL] in case of at least one ABCB1 1199A allele versus 1.5 mg/dL [0.7-3.7 mg/dL] for homozygous carriers of wild-type allele, P < 0.01). ABCB1 1199G>A polymorphism and donor age had an independent impact on both serum creatinine and estimated glomerular filtration rate. Unlike donor age, the mutated ABCB1 1199A allele was found to have a protective effect on renal function.

CONCLUSIONS

Donor age and ABCB1 1199G>A polymorphism affect long-term renal function after transplantation. Analysis of genetic factors offers a promising approach to calcineurin inhibitor toxicity risk assessment.

A review of utility-based allocation strategies to maximize graft years of deceased donor kidneys

With the continuing shortage of deceased donor kidneys coupled with a growing number of older potential recipients, there has been a greater acceptance of using older donor kidneys, including increased utility of expanded criteria donor (ECD) kidneys. In this review, we will look at the impact of using ECD kidneys on graft and patient survival, and to identify modifiable factors that may improve transplant outcomes in recipients receiving ECD kidneys. In addition, we will discuss whether the implementation of utility-based allocation strategies to maximize graft outcomes is an appropriate way forward to provide a better balance between utility and equity in the distribution of deceased donor kidneys.

Donor effect on cortical perfusion intensity in renal allograft recipients: a paired kidney analysis

BACKGROUND

The contributions of donor- and recipient-related factors to renal allograft hemodynamics are difficult to dissect due to methodological reasons. We analyzed 28 pairs of kidneys (each pair from the same donor) transplanted to 56 different recipients in order to define the contributions of the donor and the recipient to allograft hemodynamics.

METHODS

Two different techniques based on color-coded duplex ultrasound were used: renal resistance index (RI; measured in 3 different segmental arteries) and cortical perfusion intensity (PI; calculated as the average PI of selected cortical parenchymal regions during one heart cycle in standardized registered and processed ultrasound videos). All measurements were performed during the same study visit.

RESULTS

Donor age was 56 years (median, range 17-78) and recipient age at examination 54 years (range 30-77). Median time after transplant (at the date of examination) was 2.4 years (range 0.7-5.5). RI correlated with pulse pressure (r = 0.64; p < 0.001) and recipient age (r = 0.42; p < 0.03), but not with donor age or transplant function expressed as estimated glomerular filtration rate (eGFR) or PI. In within- and between-pairs ANOVA, donor-derived factors determined eGFR (p < 0.02) and cortical PI (p < 0.03), but not RI.

CONCLUSIONS

Intrinsic donor-derived factors are associated with GFR and cortical parenchymal perfusion intensity, but not the RI of segmental arteries in renal allografts.

A pair analysis of the delayed graft function in kidney recipient: the critical role of the donor

PURPOSE

The aim of this study was to analyze the importance of donor factors and especially the potential role of hemodynamic management in regard to delayed graft function in paired kidney recipient patients after renal transplantation and to analyze the urine of organ donors by proton-nuclear magnetic resonance spectroscopy to identify urine markers potentially correlated with delayed graft function in recipient patients.

METHODS

A prospective multicenter epidemiologic study was conducted. A logistic regression model taking into account paired data was used.

RESULTS

Data from 72 donors and the 144 corresponding paired recipients were analyzed. Univariate analysis showed that age of donor, previous history of tobacco, ischemic cause of brain death, norepinephrine infusion, and recipient age were the risk factors for delayed graft function. After adjusting for correlated outcome data and controlling for other potential prognostic factors, 3 variables remained significantly associated with outcome: donor age (odds ratio [OR], 10.7), hemodynamic status (OR, 0.167), and hydroxyl-ethyl starch infusion (OR, 0.135). Proton-nuclear magnetic resonance analysis evidenced 3 metabolites of interest in donors (trimethylamine-N-oxide, citrate, and lactate). However, these peaks were not correlated the clinical parameters in donors.

CONCLUSIONS

Paired analysis of kidney transplantation emphasizes the important role of factor donor associated with delayed graft function in recipient. Thus, a particular attention should be paid to the hemodynamic management of donor.

"Nature versus nurture" study of deceased-donor pairs in kidney transplantation

Donor characteristics such as age and cause of death influence the incidence of delayed graft function (DGF) and graft survival; however, the relative influence of donor characteristics ("nature") versus transplant center characteristics ("nurture") on deceased-donor kidney transplant outcomes is unknown. We examined the risks for DGF and allograft failure within 19,461 recipient pairs of the same donor's kidneys using data from the US Renal Data System. For the 11,894 common-donor pairs transplanted at different centers, a recipient was twice as likely to develop DGF when the recipient of the contralateral kidney developed DGF (odds ratio [OR] 2.05; 95% confidence interval [CI] 1.82 to 2.30). Similarly, for 7567 common-donor pairs transplanted at the same center, the OR for DGF was 3.02 (95% CI 2.62 to 3.48). For pairs transplanted at the same center, there was an additional 42% risk for DGF compared with pairs transplanted at different centers. After adjustment for DGF, the within-pair ORs for allograft failure by 1 yr were 1.92 (95% CI 1.33 to 2.77) and 1.77 (95% CI 1.25 to 2.52) for recipients who underwent transplantation at the same center and different centers, respectively. These data suggest that both unmeasured donor characteristics and transplant center characteristics contribute to the risk for DGF and that the former also contribute significantly to allograft failure.

Association between primary graft dysfunction among lung, kidney and heart recipients from the same multiorgan donor

Even organs from an ideal donor will occasionally develop primary graft dysfunction (PGD) causing a significant morbidity and mortality after transplantation. It is likely that this situation represents subtle undetectable levels of ongoing donor organ dysfunction. The aim of this study is to investigate the association of PGD between lung, kidney and heart recipients from the one donor. From 202 multiorgan donors, contributed 231 consecutive lung transplants at the Alfred Hospital, 378 kidney and 114 heart transplants were subsequently performed at multiple centers across Australia and New Zealand. Eight hundred seventy-five organs were used for 723 transplants. The incidence of PGD after lung, kidney and heart transplants was 20% (47/231), 24% (92/378) and 20% (23/114), respectively. In paired single organ recipients, PGD in one of the pair was a significant risk factor for the development of PGD in the other [lung: odds ratio = 5.63 (1.72-18.43), p = 0.004; kidney: odds ratio = 3.19 (1.90-5.35), p < 0.0001]. In multivariate analysis, same donor heart PGD [3.37 (1.19-9.50), p = 0.02] was an independent risk factor for lung PGD and same donor lung PGD was significant risk factor for kidney PGD [1.94 (1.01-3.73), p = 0.04], if the PGD status of the paired kidney was not known. There was a significant association for the development of PGD across different organs transplanted from the same donor.

Pretransplant donor-specific and non-specific immune parameters associated with early acute rejection

BACKGROUND

New immunosuppression protocols have resulted in decreased rates of biopsy-proven acute rejection; however, it is unclear whether recipients without biopsy-proven acute rejection are still at risk for immune complication and chronic allograft dysfunction. The aim of our studies was to determine whether pretransplant immune parameters were associated with posttransplant early acute rejection, unstable creatinine courses, and poor graft outcome.

METHODS

Immune parameters, including human leukocyte antigen (HLA) mismatch, HLA-specific antibodies, global CD4+ cellular response as measured by intracellular adenosine triphosphate (iATP) synthesis, and IFN-gamma precursor frequencies to donor or third-party cells as measured by ELISPOT were determined for a total of 126 kidney recipients treated with a protocol, including rapid discontinuation of prednisone.

RESULTS

The donor specific pretransplant parameters of HLA class I mismatches (P=0.04) and total HLA mismatches (P=0.04) with the donor as well as the pretransplant HLA-donor specific antibodies (P=0.002) were associated with biopsy-proven acute rejection. Higher pretransplant iATP levels, a donor nonspecific parameter, were found associated with biopsy proven acute rejection (P=0.04). Pretransplant iATP levels were significantly greater for recipients with early unstable creatinine levels (P=0.01). Recipients with a pretransplant iATP value greater than 375 ng/ml were 3.67 times more likely to experience acute rejection (P=0.03).

CONCLUSIONS

Pretransplant assessment of donor specific and nonspecific immune parameters may identify recipients who can benefit from closer clinical and immunological surveillance to allow for tailored immunsuppression and selective intervention aimed at optimizing both short and long-term graft outcome.

Donor Structural and Functional Parameters Are Independent Predictors of Renal Function at 3 Months

INTRODUCTION

Epidemiological studies have shown that demographic, clinical, and histological donor characteristics influence renal function after transplantation, but whether these variables are independent predictors has not been established. The aim of this study was to evaluate the relative contribution of different donor variables on glomerular filtration rates (GFRs) at 3 months.

PATIENTS AND METHODS

We analyzed single renal transplants performed at our center from January 2000 to July 2004. Donor variables included age, gender, weight and height, cause of death, duration of brain death, serum creatinine at admission and preprocurement, history of arterial hypertension or diabetes mellitus, and smoking habit. Donor chronic damage score was calculated in preimplantation biopsies as was the addition of interstitial fibrosis, fibrous intimal thickening, and glomerulosclerosis (<10% = 0, >10% = 1). Donor and recipient GFRs were calculated according to the Cockroft-Gault formula.

RESULTS

We analyzed 202 transplants obtained from 113 deceased donors. A renal biopsy was available in 111 transplants. Recipient GFR at 3 months correlated negatively with donor age (R = -0.32, P < .01) and donor chronic damage score (R = 0.32, P < .01). GFR was lower among recipients of female versus male donors (50 +/- 15 vs 60 +/- 20 mL/min; P < .01). Donor cerebrovascular accident death (53 +/- 19 vs 63 +/- 19 mL/min; P < .01) and hypertension (48 +/- 16 vs 59 +/- 20 mL/min; P < .01) were also associated with lower GFR at 3 months. There was a positive correlation between GFR at admission, GFR preprocurement, and GFR at 3 months (R = 0.32 and R = 0.18 respectively; P < .01). Stepwise regression analysis included chronic damage score, GFR at admission, and donor gender but not donor age as independent predictors of GFR at 3 months (R = 0.50; P < .01).

CONCLUSION

Donor structural and functional parameters are independent predictors of renal function at 3 months.

Effect of brain-dead donor resuscitation on delayed graft function: results of a monocentric analysis

BACKGROUND

We have previously shown that a delayed graft function (DGF) longer than 6 days was a crucial threshold for long-term graft outcome. The aim of this study was to analyze the correlation of DGF >or=6 days with brain-dead donor variables, including those related to resuscitation, in a population of 262 consecutive brain-dead donors from 1990 to 2003.

METHODS

We used a marginal logistic model in which DGF was considered as a binary variable with a cutoff of 6 days.

RESULTS

Monovariate analysis of donor parameters showed that male, age above 35 years, primary history of hypertension, hydroxyethyl starch (HES) fluid greater than 1500 mL or epinephrine infusion during resuscitation were risk factors for prolonged DGF. The multivariate logistic regression model showed that epinephrine use during donor resuscitation (P<0.001, odds ratio [OR]=4.35), cold ischemia time (CIT) >or=16 hr (P=0.01, OR=2.16), and recipient age >55 years (P=0.003, OR=2.75), were associated with a risk of prolonged DGF. A long stay (>40 hr) in intensive care and a large volume of colloids (>1250 mL, except HES) correlated with a lower risk of DGF.

CONCLUSION

Our study shows an impact for only a limited number of brain dead donor resuscitation parameters on DGF duration. We also show that CIT has a much lower threshold (<16 hr) for DGF risk than previously described. Importantly, we show that recipient age is clearly a major independent risk factor for prolonged DGF, whereas donor age seems to act mostly as a dependent risk factor.

Risk factors for rising creatinine in renal allografts with 1 and 3 yr survival

BACKGROUND

Determining factors associated with negative slope of inverse creatinine vs. time (1/Cr vs. t) may help prevent a decline in renal allograft function.

METHODS

A total of 1389 adult recipients of primary renal transplants were divided into quartiles based on the slope of 1/Cr vs. t calculated from 6 and 12 months post transplant. A multivariate analysis of risk factors for being in the worst vs. best quartile employed these variables: donor source, HLA mismatch, recipient age, donor age, panel-reactive antibody (PRA), acute rejection (AR), 3-month cyclosporin A (CsA) level, 1-yr CsA level and acute tubular necrosis. Two separate analyses compared risk factors in patients with 1 and 3 yr survival, respectively.

RESULTS

In recipients with > or = 1 yr graft survival, high PRA and AR were associated with negative slopes of 1/Cr vs. t. For those with > or = 3 yr graft survival, both AR and 3-month CsA level > 150 ng/mL were significant risk factors, using both 6- and 12-month slopes. Stratification of AR showed 1 AR episode > or = 6 months and multiple AR episodes carried significant risk for negative slopes.

CONCLUSION

Optimization of allograft function invokes a conundrum between the needs to avoid both AR and high early CsA levels. We support a policy of carefully balancing these two risks.

Feasibility and Utility of a Lung Donor Score: Correlation With Early Post-Transplant Outcomes

BACKGROUND

A lung donor score may provide a numerical value of overall donor lung "quality" to allow comparison among different organizations and research protocols. This study aims to develop a simple scoring system and investigate its applicability on predicting donor selection and early post-lung-transplant (LTx) outcomes.

METHODS

Data of all donors referred to our institution in 2001 were initially analyzed to create a LTx donor score. Five domains, age, smoking history, chest X-ray, secretions, and arterial blood gas results, were included. A larger cohort of transplant recipients (years 2002 to 2005) was analyzed to validate the score against early post-LTx outcomes.

RESULTS

In the initial 2001 cohort, 36 of 87 (41%) donors were used for 41 LTx (used group) and 51 (59%) were declined for medical (lung-exclusion group, n = 31) and general (general-exclusion group, n = 20) reasons. The median donor scores in the used, general-exclusion, and lung-exclusion groups were 2.0, 2.0, and 10.0, respectively (p < 0.0001). In multivariate analysis of the validation cohort, the donor score in bilateral LTx was significantly associated with post-transplant ratio of arterial oxygen tension and inspired oxygen fraction (coefficient = -16.19, p = 0.002), primary graft dysfunction grade (coefficient = 0.21, p < 0.0001), and intubation hours (coefficient = 0.05, p = 0.04); however, a significant association was not seen in single LTx.

CONCLUSIONS

A proposed simple donor scoring system, based on five major donor variables available at the time of donor selection, may be useful for data comparison between specific centers, quality control, evaluative research, and clinical decision making in donor selection and management in LTx.

Perioperative fluid management in renal transplantation: a narrative review of the literature

Adequate volume maintenance is essential to prevent acute renal failure during major surgery or to ensure graft function after renal transplantation. The various recommendations on the optimum fluid therapy are based, at best, on sparse evidence only from observational studies. This article reviews the literature on perioperative fluid management in renal transplantation. Crystalloid solutions not exerting any specific side-effects are the first choice for volume replacement in kidney transplantation. The use of colloids should be restricted to patients with severe intravascular volume deficits necessitating high volume restoration. The routine application of albumin, dopamine, and high dose diuretics is no longer warranted. Mannitol given immediately before removal of the vessel clamps reduces the requirement of post-transplant dialysis, but has no effects on graft function in the long term. There is insufficient evidence on the best use of dialysis, but it seems peritoneal dialysis pretransplant is associated with less delayed graft function, whereas the preference of dialysis post-transplant is not yet well-founded. This review article should provide better guidance for fluid management in kidney transplantation until best-evidence guidelines can be established based upon more research.

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.

Transplantation rénale du sujet âgé

For ten years, an increase in the number of elderly patients on renal transplant waiting lists has occured. In an attempt to close the widening gap between supply and demand and because the demand for kidneys for younger patients already surpasses the supply, transplant physicians nowadays accept organs from older donors that might have been deemed inappropriate in the past. Programs of age matching between donors and recipients and of dual-kidneys transplantation have emerged. The initial results of these programs are encouraging with excellent patient and graft survival at one and three years.

Impact of initial exposure to calcineurin inhibitors on kidney graft function of patients at high risk to develop delayed graft function

We conducted a retrospective analysis of the influence of full doses of calcineurin inhibitors [8-10 mg kg-1 day-1 cyclosporine (N = 80), or 0.2-0.3 mg kg-1 day-1 tacrolimus (N = 68)] administered from day 1 after transplantation on the transplant outcomes of a high-risk population. Induction therapy was used in 13% of the patients. Patients also received azathioprine (2 mg kg(-1) day(-1), N = 58) or mycophenolate mofetil (2 g/day, N = 90), and prednisone (0.5 mg kg(-1) day(-1), N = 148). Mean time on dialysis was 79 +/- 41 months, 12% of the cases were re-transplants, and 21% had panel reactive antibodies > 10%. In 43% of donors the cause of death was cerebrovascular disease and 27% showed creatinine above 1.5 mg/dL. The incidence of slow graft function (SGF) and delayed graft function (DGF) was 15 and 60%, respectively. Mean time to last dialysis and to nadir creatinine were 18 +/- 15 and 34 +/- 20 days, respectively. Mean creatinine at 1 year after transplantation was 1.48 +/- 0.50 mg/dL (DGF 1.68 +/- 0.65 vs SGF 1.67 +/- 0.66 vs immediate graft function (IGF) 1.41 +/- 0.40 mg/dL, P = 0.089). The incidence of biopsy-confirmed acute rejection was 22% (DGF 31%, SGF 10%, IGF 8%). One-year patient and graft survival was 92.6 and 78.4%, respectively. The incidence of cytomegalovirus disease, post-transplant diabetes mellitus and malignancies was 28, 8.1, and 0%, respectively. Compared to previous studies, the use of initial full doses of calcineurin inhibitors without antibody induction in patients with SGF or DGF had no negative impact on patient and graft survival.

Risk factors for chronic allograft nephropathy after renal transplantation: a protocol biopsy study

BACKGROUND

Chronic allograft nephropathy (CAN) leads to chronic allograft dysfunction and loss. Regular renal transplant biopsies may be useful to find risk factors for CAN.

METHODS

We carried out 688 protocol biopsies in 258 patients at 6, 12, and 26 weeks after renal transplantation. Patients with signs of CAN in the biopsy 3 (N= 70, CAN group), and those without (N= 120, non-CAN group), were compared.

RESULTS

Chronic tubulointerstitial changes increased from biopsy 1 to 3 (5% vs. 37%, P < 0.0001). Fifty-six of 190 patients had acute rejection within 6 months (30%), 33 of which were found in protocol biopsies (17%). On univariate analysis, the CAN group had CAN more often at biopsy 2 than the non-CAN group (23% vs. 4%, P < 0.0001), had a lower calculated creatinine clearance at biopsy 1 and 2 (49.4 +/- 25.8 vs. 57 +/- 20.2 mL/min, P= 0.01; 47.3 +/- 21.2 vs. 57.9 +/- 19.5 mL/min, P= 0.001, respectively), had a living donor less often than a brain dead donor (7% vs. 18%, P= 0.045), had a longer cold ischemia time (17.4 +/- 7 vs. 14.9 +/- 8.1 hours, P= 0.04), and had arterionephrosclerosis more often (24% vs. 12%, P= 0.02). On multivariate analysis, the differences in CAN at biopsy 2 (P= 0.001) and lower GFR at biopsy 2 (P= 0.002) were confirmed; in addition, nephrocalcinosis (P= 0.006) and acute rejection (P= 0.046) were found to occur more often.

CONCLUSION

Chronic tubulointerstitial changes develop early after renal transplantation and are associated with reduced kidney function. Risk factors for CAN are arterionephrosclerosis (donor-related), nephrocalcinosis (related to preexisting hyperparathyroidism), a long cold-ischemia time (ischemia-perfusion-related), and acute rejection. Renal functional decline precedes morphologic changes of CAN, expressed as tubular atrophy and interstitial fibrosis.

United Network for Organ Sharing's expanded criteria donors: is stratification useful?*

The United Network for Organ Sharing (UNOS) Expanded Criteria Donor (ECD) system utilizes pre-transplant variables to identify deceased donor kidneys with an increased risk of graft loss. The aim of this study was to compare the ECD system with a quantitative approach, the deceased donor score (DDS), in predicting outcome after kidney transplantation. We retrospectively reviewed 49 111 deceased donor renal transplants from the UNOS database between 1984 and 2002. DDS: 0-39 points; >or=20 points defined as marginal. Recipient outcome variables were analyzed by ANOVA or Kaplan-Meier method. There was a 90% agreement between the DDS and ECD systems as predictors of renal function and graft survival. However, DDS identified ECD- kidneys (10.7%) with a significantly poorer outcome than expected (DDS 20-29 points, n = 5,252). Stratification of ECD+ kidneys identified a group with the poorest outcome (DDS >or=30 points). Predictability of early post-transplant events (i.e. need for hemodialysis, decline of serum creatinine and length of hospital stay) was also improved by DDS. DDS predicted outcome of deceased donor renal transplantation better than the ECD system. Knowledge obtained by stratification of deceased donor kidneys can allow for improved utilization of marginal kidneys which is not achieved by the UNOS ECD definition alone.

Cold ischaemia time added to kidneys can be minimized by completing the final cross-match before organs are taken from the operating room

Minimizing the amount of cold ischaemia time (CIT) added to cadaveric kidneys before their transplantation is an important goal since longer CIT is associated with worse long-term graft outcome. Our organ procurement organization (OPO) and HLA laboratories have taken the approach of performing the histocompatibility testing, including the final cross-match, as early in the donor process as possible.

METHODS

The data in this study were collected from all consecutive final cross-matches done for cadaveric kidney (n = 113) and simultaneous pancreas + kidney (SPK) (n = 25) transplants done with organs recovered from donors in the Midwest Transplant Network OPO from 1 January 2001 to 9 May 2002. We evaluated the time the final cross-match was completed from when the kidneys from that donor were taken from the operating room (OR) and compared that time with CIT.

RESULTS

For kidney transplants, 72% of the final cross-matches were complete before the kidneys were taken from the OR. The CIT of that group (10.4 +/- 3.8 h) was significantly lower than that of the group of kidney transplant patients whose final cross-match was done after the kidneys were taken from the OR (15.5 +/- 5.8 h) (P < 0.001). Similarly, for SPK transplants, 88% of the final cross-matches were completed before the organs left the OR and the CIT of that group (10.2 +/- 3.4 h) was less than in the group whose final cross-match was done after the organs left the OR (14.3 +/- 4.8 h) (P > 0.1).

CONCLUSIONS

These data show that the practice of completing the final cross-match as early in the donor process as possible helps to minimize the amount of cold ischaemia time added to the kidneys and pancreata before transplantation. That should reduce the detrimental influence that longer CIT has on short- and long-term function in kidney as well as SPK transplantation.

The stability of the glomerular filtration rate after renal transplantation is improving

The 6-mo function and the stability of function posttransplantation in 429 cadaver renal transplants was investigated from 1990 to 2000. The 6-mo creatinine clearance (CrCl) and the rate of change of CrCl beyond 6 mo posttransplantation were calculated. The mean 6-mo CrCl was 64.6 +/- 1.1 ml/min and was stable between 1990 and 2000. The net slope of CrCl was -1.4 +/- 0.5 ml/min per yr. The slope has improved in recent years, such that the mean slopes in the period after 1997 are actually positive (+3.5 ml/min per yr). The slope of CrCl beyond 6 mo was not related to the actual value of the 6 mo CrCl, i.e., there was no accelerated loss of function at low CrCl levels. The 6-mo CrCl was independently determined by donor factors (age, gender), recipient factors (age, gender), and immune factors (rejection episodes, regraft status). The slope of the CrCl correlated independently with the transplant year, recipient gender, rejection episodes, diastolic BP, and the choice of immunosuppressive drugs. Cytomegalovirus infection and mismatch status and lipid levels and treatment were not independently associated with slope or 6-mo CrCl. Thus, the most striking change in the course of renal transplants over the past decade is the new stability of function, correlating with reduced rejection and probably due at least in part to the new immunosuppressive agents. Despite continued calcineurin inhibitor use, late improvement in function now occurs in many cadaver kidney transplants, suggesting a previously unappreciated capacity for functional adaptation.

Predicting long-term kidney graft survival: can new trials be performed?

BACKGROUND

As short-term transplant results improve, it has become difficult to use patient or graft survival or acute rejection as clinical trial endpoints, except in large, multicenter studies. Despite better outcomes, graft failure continues over time.

METHODS

We studied 6- and 12-month creatinine (Cr) level and change in creatinine (deltaCr) level (3-12 months, 6-12 months) as predictors of graft survival for 1,389 primary kidney transplants (minimum graft survival 1 year). Determining the prognostic value of Cr level (6 or 12 months), the subgroups were as follows: less than 1, 1 to 1.4, 1.5 to 1.9, 2.0 to 2.4, 2.5 to 2.9, and greater than or equal to 3 mg/dL. For deltaCr level, the subgroups were as follows: less than 0, 0, 0.01 to 0.2, and greater than 0.2. Subgroup actuarial graft survival was determined. Cox regression analyses were performed with forward, stepwise selection.

RESULTS

After 12-month Cr level entered the model, no other variable was significant. Repeating this with continuous variables, 12-month Cr level was again the best predictor. Five-year graft survival for 12-month Cr level less than 1 (n=38) was 95%; for 1.0 to 1.4 (n=454), 87%; for 1.5 to 1.9 (n=463), 86%; for 2.0 to 2.4 (n=166), 78%; for 2.5 to 2.9 (n=54), 60%; for greater than or equal to 3 (n=45), 41%. A major breakpoint for outcome is 1-year Cr level=2.0. A power analysis was performed for the combined endpoint of graft loss and 1-year Cr level greater than 2, reached by 30% of patients. To avoid missing a reduction to 20% (actual decrease 33%) (alpha=0.05; power=0.8), 313 patients would be required per group. For a reduction to 15% (actual decrease 50%), 133 patients would be required.

CONCLUSIONS

Twelve-month Cr level is an accurate surrogate for long-term outcome. The use of a combined endpoint (graft loss and 12-month Cr level) allows trials to be performed without exorbitant numbers.

The relationship between donor age and cadaveric renal allograft survival is modified by the recipient's blood pressure

Increasing donor age correlates with reduced renal allograft survival. In this study we analyzed variables that may modify this relationship. The study included 1285 cadaveric kidney allograft recipients followed for 7.2 + 4.5 years. By Cox, increasing donor age beyond 30 years was associated with significant increases in the hazard ratio for graft loss [age 31-46, hazard ratio (HR) = 1.4, p = 0.02; 46-60, HR = 1.55, p = 0.008; > 60, HR = 1.68, p = 0.03]. Increasing donor age was significantly associated with: older and heavier recipients; higher creatinine and blood pressure (BP) 6 months post-transplant; and lower total cyclosporine dose during the first year. Of interest, the 6-month serum creatinine and the BP level modified significantly the relationship between age and survival. Thus, increasing donor age was significantly related to reduced graft survival only in patients with a 6-month creatinine < 2 mg/dL. Furthermore, donor age related significantly to graft survival only among patients with higher BP levels 6 month post transplant. It is concluded that increasing donor age is associated with reduced cadaveric graft survival, but that relationship is significantly modified by graft function and BP. These data suggest that poorly functioning kidneys have reduced survival irrespective of age. Furthermore, elevated BP levels may have a particularly negative effect on the survival of older grafts.

Multivariate analysis of donor risk factors for graft survival in kidney transplantation

BACKGROUND

The results of the transplantation of marginal donor kidneys remain controversial. This study aimed to investigate the impact of donor risk factors as predictors of kidney-graft outcome.

METHODS

Allograft failure risk factors were studied in 7,209 cadaveric kidney-transplant recipients reporting to the Etablissement français des Greffes (EfG) from 1996 to 2000, of which 544 (7.6%) were from donors aged over 60. Both univariate and multivariate analysis were used to assess the effect of donor risk factors and were stratified according to recipient age.

RESULTS

Overall graft survival was 91.1% (95% confidence interval [CI] 90.5-91.8) at 1 year, 88.6% (95% CI 87.8-89.4) at 2 years, and 85.6% (95% CI 84.6-86.6) at 3 years posttransplant. Univariate analysis of risk factors showed a significant reduction of graft survival in recipients transplanted with kidneys coming from donors older than 60 years, donors with a history of hypertension, a cerebrovascular cause of death, and a preharvesting serum creatinine greater than 150 micromol/L. Multivariate analysis revealed significantly higher failure rate associated with cerebrovascular cause of death (RR=1.2, P=0.02), history of hypertension (RR=1.2, P=0.04), and elevated serum creatinine (RR=1.3, P=0.03), whereas donor age greater than 60 years was not found as an independent risk factor.

CONCLUSIONS

Our results suggest that cerebrovascular cause of death, history of hypertension, and elevated creatinine are significant independent donor risk factors for graft survival, whereas donor age is a statistically significant, but dependent, risk factor. This result is important for the design of allocation and transplantation strategies for kidneys procured in elderly donors.

Donor tissue characteristics influence cadaver kidney transplant function and graft survival but not rejection

Acute injury and age are characteristics of transplanted tissue that influence many aspects of the course of a renal allograft. The influence of donor tissue characteristics on outcomes can be analyzed by studying pairing, the extent to which two kidneys retrieved from the same cadaver donor manifest similar outcomes. Pairing studies help to define the relative role of donor-related factors (among pairs) versus non-donor factors (within pairs). This study analyzed graft survival for 220 pairs of cadaveric kidneys for the similarity of parameters reflecting function and rejection. It also examined whether the performance of one kidney was predicted by the course of its "mate," the other kidney from that donor. Parameters reflecting function showed sustained pairing posttransplantation, as did graft survival. In contrast, measures of rejection strongly affected survival but showed no pairing. Surprisingly, the survival of a kidney was predicted by the early performance of its mate, an observation we term the "mate effect." Six-month graft survival and renal function were reduced in grafts for which the mate kidney displayed any criteria for functional impairment (dialysis dependency, low urine output [</=1 L] in the first 24 h posttransplant or day-7 serum creatinine >/= 400 micro mol/L), even for kidneys which themselves lacked those criteria. Rejection measures did not demonstrate the mate effect. In conclusion, kidney transplant function is strongly linked to donor-related factors (age, brain death). In contrast, rejection affects survival and function, but it is not primarily determined by the characteristics of the donor tissue. Graft survival reflects both of these influences.

Combined analysis of cytokine genotype polymorphism and the level of expression with allograft function in African-American renal transplant patients

Cytokine gene polymorphism and expression levels were evaluated in a group of African-American patients who had undergone renal transplantation. It was hypothesized that possession of specific cytokine alleles might be influential in predisposing the recipient to allograft rejection. Thus, we sought to establish a relationship between cytokine gene polymorphism, the levels of cytokine expression, and the outcome of allograft function. Cytokine genotypes and mRNA transcript levels of IL-2, TNF-alpha, TGF-beta1, IL-10, IL-6 and IFN-gamma were determined using peripheral blood cells. Genomic DNA samples from 77 transplant recipients and 77 controls were tested by a multiplex PCR with specific primers for the above cytokines. The frequency distributions of cytokines were analyzed in respect to the clinical characterization, including delayed graft function (DGF), rejection episodes (REs) and stable graft function (SGF). The mRNA transcript level was tested both at pre- and early post-transplantation (day 1 and day 4) with primers for coding regions of the above cytokines in a RT-PCR assay. The majority of recipients with successful graft function were matched with their donors for only three out of the six HLA alleles. We have shown that the TGF-beta1 T/C G/G high producer and IFN-gamma T/A intermediate producer genotypes were associated with allograft rejection, whereas low IFN-gamma producer and high IL-10 producer genotypes were significantly protective of the allograft. There was some correlation between the TGF-beta1 high producer genotype and DGF, but it was not statistically significant. Overall, 77% of those who experienced REs carried the TGF-beta1 T/C G/G, high producer genotype as compared with 52% who experienced DGF, 39% with SGF (P<0.01, RR=2.0), and 27.3% of controls (P<0.003, RR=2.6). The IFN-gamma T/A intermediate producer genotype was found in 69.2% of patients with REs as compared with 26.8% of patients with SGF (P<0.008, RR=2.85). The IL-10, ATA/ATA low producer genotype was found in 38.5% of recipients with REs and 14.6% of recipients without REs (P<0.04, RR=0.53). Expression levels of mRNA transcript were correlated with genotype data, except for the TGF-beta1 high producer genotype where there was no significant difference between the level of mRNA transcript at pre- and post-transplantation. Low DRbeta1 and high DPbeta1 expression by recipient peripheral blood mononuclear cells before transplantation was associated with more SGF, whereas high DRbeta1 and low DPbeta1 expression at pretransplantation was associated with more REs (DRbeta1, P<0.001 and DPbeta1, P<0.05, respectively). We concluded that, dual analysis of cytokine genotype and expression levels by peripheral cells may be an important clue to understanding the contribution of the recipient's immune response to an allograft pre- and post-transplantation. Identification of peripheral markers diagnostic of rejection could allow advance anticipation of clinical outcome, and might reduce the need for tissue biopsy.

The impact of obesity in renal transplantation: an analysis of paired cadaver kidneys

BACKGROUND

Previous studies indicate that obesity is a risk factor in renal transplantation. However, these analyses did not control for variable donor factors that may strongly influence outcome. To control for donor variables such as age, cause of death, procurement techniques, preservation methods, cold ischaemia time and implantation technique, we analysed patient and graft survival in recipients of paired kidneys, derived from the same procurement procedure, preserved in the same manner, subjected to similar cold ischaemia time and implanted by the same surgical team. Between June 1992 and August 1999, 28 procurement procedures provided kidneys which were transplanted into one obese and one non-obese recipient. Body mass index (BMI) was calculated as kg/m2. Recipients were classified as obese (BMI > 30) or non-obese (BMI < 30). Immunotherapy for all recipients consisted of a triple therapy regimen of cyclosporine or prograf, azathioprine or cellcept, and prednisone. Patients with delayed graft function (DGF), defined as the need for dialysis within 72 h of the transplant procedure, were treated with anti-thymocyte globulin (ATG) or thymoglobulin (TMG) induction for 5-7 d. The rate of DGF (7.1 versus 10.7%) and acute rejection (39.3 versus 35.7%) were similar in the obese and non-obese recipient groups. Patient survival was similar at 1, 3 and 5 yr in both groups. In addition, graft survival was similar at 1 yr. However, a trend toward decreased medium-term graft survival, which reached significance at 5 yr, was observed in the obese group. Furthermore, mean serum creatinine at 1 yr was higher in the obese group (2.0) compared with the non-obese group (1, 4) (p=0.12). This analysis of paired cadaver kidneys indicated that obesity is not a risk factor for DGF, acute rejection, and 1-yr graft survival. However, a decreased medium- and long-term graft survival trend, which reached statistical significance at 5 yr, was observed in obese recipients.