Early graft function and patient survival following cadaveric renal transplantation

Trends and Outcomes of Hypothermic Machine Perfusion Preservation of Kidney Allografts in Simultaneous Liver and Kidney Transplantation in the United States

Optimal kidney graft outcomes after simultaneous liver-kidney (SLK) transplant may be threatened by the increased cold ischemia time and hemodynamic perturbations of dual organ transplantation. Hypothermic machine perfusion (MP) of kidney allografts may mitigate these effects. We analyzed U.S. trends and renal outcomes of hypothermic non-oxygenated MP vs. static cold storage (CS) of kidney grafts from 6,689 SLK transplants performed between 2005 and 2020 using the United Network for Organ Sharing database. Outcomes included delayed graft function (DGF), primary non-function (PNF), and kidney graft survival (GS). Overall, 17.2% of kidney allografts were placed on MP. Kidney cold ischemia time was longer in the MP group (median 12.8 vs. 10.0 h; p < 0.001). Nationally, MP utilization in SLK increased from <3% in 2005 to >25% by 2019. Center preference was the primary determinant of whether a graft underwent MP vs. CS (intraclass correlation coefficient 65.0%). MP reduced DGF (adjusted OR 0.74; p = 0.008), but not PNF (p = 0.637). Improved GS with MP was only observed with Kidney Donor Profile Index <20% (HR 0.71; p = 0.030). Kidney MP has increased significantly in SLK in the U.S. in a heterogeneous manner and with variable short-term benefits. Additional studies are needed to determine the ideal utilization for MP in SLK.

Estimating the correlation between semi-competing risk survival endpoints

Time-to-event, bivariate, semi-competing risk data occur when a terminal event can censor a non-terminal event, but not vice versa. There are potential correlations between these endpoints as they are measured on the same individual. However, traditional methods to estimate the correlations cannot be used directly due to the censoring of time-to-event endpoints. We develop methods using a copula-based approach to study the dependence structures between the two survival endpoints. We use a variety of copulas to estimate the correlation between endpoints and to acknowledge different dependence structures. The estimated association parameter in the copula function is transformed into Spearman's rank correlation coefficient. We conduct a simulation study to evaluate the estimation from the proposed models along with the effects of misspecification of the copula functions and survival distributions. The proposed methods are applied to two real-life data sets.

Impact of donor obesity on allograft outcomes after kidney transplantation adjusted for kidney donor profile index - a national cohort study

Obesity in deceased kidney donors is a known risk factor for poor allograft outcomes. The Kidney Donor Profile Index (KDPI) has been introduced to predict graft survival in deceased donor kidney transplantation (DDKT). Obesity, however, is not included in KDPI. We study the impact of donor obesity on DDKT outcomes after adjusting for organ quality by KDPI. The Organ Procurement Transplantation Network/United Network for Organ Sharing (OPTN/UNOS) data of DDKT from 2005 to 2017, with donor BMI ≥ 18.5 kg/m² and weight >80 kg were included. There was a total of 66 382 DDKTs with 10 917 death-censored graft failures. For KDPI ≤ 30%, the 10-year death-censored graft survival (DCGS) rates among donor BMI < 30, 30-35, 35-40, 40-45 and ≥45 kg/m² groups were 75.9%, 75.4%, 76.1%, 74.9% and 79.6%, respectively. For KDPI > 30%, 10-year DCGS rates were 67.5%, 66.1%, 65.9%, 62.6% and 63.2%, respectively. After adjusting for known confounding factors including KDPI, donor obesity was not independently associated with an increased risk for graft failure. In DDKT with donor weight >80 kg, donor obesity was not associated with a lower long term DCGS compared to non-obesity when KDPI ≤ 30%.

Early Postoperative Complications and Outcomes of Kidney Transplantation in Moderately Obese Patients

BACKGROUND

Obese renal transplant recipients (body mass index [BMI] ≥30 kg/m²) are at risk of delayed graft function and postoperative complications, such as infections or delayed wound healing. There is also a tendency to exclude extremely obese patients from transplantation (KTx). Nonetheless, no association between obesity and increased mortality has been reported. The aim of this study is to evaluate the effect of BMI on the most common surgical and infectious complications after KTx.

MATERIALS AND METHODS

An observational study in 872 patients transplanted from 2010-2017 was conducted. Median BMI was 24.6 (13.9-34.3), and 8.3% of the group was obese. Patient records were searched for early postoperative complications: lymphocele or hematoma (>33 mL), urinary leakage, or urinary tract infection (UTI). Mann-Whitney U and χ² or Fisher exact tests were used. P < .05 was considered statistically significant. The study complies with the Helsinki Congress and the Istanbul Declaration.

RESULTS

Renal primary nonfunction was observed in 1.4% (12/872) of patients. Surgical or infectious complications occurred in 52.7% (453/860) of patients. No correlation between BMI and complication rate was noted. Complications were observed in 56.9% (41/72) of obese vs 52.3% (412/788) of nonobese patients (P = .448), including lymphocele in 15.3% vs 16.4% (P = .810), hematoma in 22.2% vs 19.2% (P = .530), urinary leakage in 1.4% vs 4.6% (P = .203), and UTI in 31.9% vs 32.9% (P = .873), respectively.

CONCLUSIONS

Recipient's BMI has no significant association with the most common surgical complications after KTx. There is no need to delay KTx in moderately obese patients.

Impact of Cytomegalovirus Serostatus on Allograft Loss and Mortality Within the First Year After Kidney Transplantation: An Analysis of the National Transplant Registry

BACKGROUND

Cytomegalovirus (CMV) infection is one of the leading causes of morbidity and mortality in kidney transplantation (KT) recipients. We investigated the association of CMV serostatus and patient outcomes within the first year after KT.

METHODS

All KT recipients between January 1, 2007 and December 31, 2017 were identified from the Thai Transplant Registry. The prevalence rates of allograft loss and mortality within the first year after KT were estimated by the Kaplan-Meier method. The CMV serostatus in donors (D) and recipients (R) was assessed as a prognostic factor for allograft loss and mortality within the first year by the Cox proportional hazards model.

RESULTS

During the 10-year study period (2007-2017), there were 4556 KT recipients with a mean ± standard deviation age of 43 ± 14 years, and 63% of the recipients were male. Deceased-donor KT and induction therapy were performed in 52% and 58% of the recipients, respectively. Among the 3907 evaluable patients, the rates of cases with D⁺/R⁺, D⁺/R^-, D^-/R⁺, and D^-/R^- as the CMV serostatus were 88.9%, 6.1%, 2.9%, and 1.9%, respectively. The estimated prevalence rates of allograft loss and mortality within the first year were 3.8% and 2.8%, respectively. In univariate analysis, CMV D⁺/R^- serostatus was significantly associated with mortality (hazard ratio [HR], 2.10; 95% confidence interval [CI], 1.18-3.75; P = .01) but not with an allograft loss (HR, 1.51; 95% CI, 0.85-2.66; P = .16) within the first year after KT. In multivariate analysis, CMV D⁺/R^- serostatus of D⁺/R^- was associated with mortality within the first year after KT (HR, 2.04; 95% CI, 1.05-3.95; P = .04). Other independent prognostic factors for mortality were old recipient age, deceased-donor KT, and hemodialysis after KT.

CONCLUSIONS

In a national setting with predominant CMV seropositivity in both D and R, CMV seromismatch was associated with poor patient survival within the first year after KT.

Outcomes From Right Versus Left Deceased-Donor Kidney Transplants: A US National Cohort Study

RATIONALE & OBJECTIVE

There may be important transplant-related differences between right and left kidneys, including logistical/surgical considerations about vessel length for the right compared to the left kidney from the same donor. Because US centers choose between the right and left kidney when their recipient is ranked higher on a "match-run," we sought to determine whether deceased-donor right kidneys have had worse posttransplantation outcomes than left kidneys.

STUDY DESIGN

Paired Organ Procurement and Transplantation Network analysis.

SETTING & PARTICIPANTS

Deceased-donor kidney pairs transplanted during 1990 to 2016.

EXPOSURE

Right versus left kidney controlling for other significant factors.

OUTCOMES

Delayed graft function (DGF), all-cause and death-censored graft failure, and mortality.

ANALYTICAL APPROACH

Multivariable conditional logistic regression for DGF; proportional hazards models (conditional on same donor) for failure/mortality with right kidneys (operationalized as 6-month time-varying coefficients) adjusting for DGF and other confounders.

RESULTS

87,112 recipient pairs shared the following donor characteristics: mean age of 41 ± 14 years, 60% males, and 11% with cardiac death. Recipient characteristics were numerically similar by donor kidney side but with some statistical differences given the sample size. Right kidneys had slightly longer cold ischemia time. DGF occurred more often for right kidneys (28% vs 25.8%; P < 0.001; adjusted OR, 1.15 [95% CI, 1.12-1.17]). The adjusted hazard ratio (aHR) for all-cause graft failure with right kidneys within 6 months was 1.07 (95% CI, 1.03-1.11), and was 0.99 (95% CI, 0.97-1.01) thereafter. The aHRs for death-censored graft failure with right kidneys before and after 6 months were 1.11 (95% CI, 1.06-1.16) and 0.96 (95% CI, 0.93-0.99), respectively; the corresonding aHRs for mortality were 0.99 (95% CI, 0.93-1.04) and 1.00 (95% CI, 0.98-1.03), respectively.

LIMITATIONS

Registry data, different transplant eras, reasons for kidney side unavailable.

CONCLUSIONS

There is modest association for transplantation of right kidneys with DGF and graft loss within the first 6 months, which is lost beyond this time point. These findings do not support the use of laterality of deceased-donor kidneys as an important factor in organ acceptance decisions.

Impact of Conversion From Cyclosporine to Tacrolimus on Glucose Metabolism and Cardiovascular Risk Profiles in Long-Term Stable Kidney Transplant Recipients

BACKGROUND

Compared to tacrolimus, cyclosporine increases cardiovascular risk. Furthermore, tacrolimus has a negative effect on glucose metabolism compared to cyclosporine. This study investigated the effect of the conversion from cyclosporine to tacrolimus for immunosuppressive therapy on glucose metabolism and cardiovascular risk profiles in long-term stable kidney transplant recipients (KTRs).

METHODS

In this prospective, open-label, single-arm study, 36 KTRs were enrolled; 3 were excluded. Patients were evaluated for glucose metabolism and cardiovascular risk factors at baseline, 3, and 6 months after conversion of medication. Serial changes were analyzed by repeated analysis of variance.

RESULTS

The mean duration from transplantation was 12.6 ± 4.0 years and baseline serum creatinine levels were 1.10 ± .23 mg/dL. After conversion, fasting plasma glucose levels increased sequentially from 101.7 ± 18.5 to 107.4 ± 21.3 mg/dL (P = .007), and glycated hemoglobin levels increased from 5.7 ± .8 to 6.0 ± 1.2% (P = .016). Among cardiovascular risk factors, fibrinogen levels were decreased (P = .015), but other factors, including blood pressure and lipid profile, did not change (all P > .05). There was no change in renal function, including serum creatinine (P = .611) and urine protein-to-creatinine ratio (P = .092). Body mass index levels were decreased (P = .037) and body weight tended to decrease (P = .063).

CONCLUSIONS

Switching immunosuppressant therapy to tacrolimus has an apparent negative effect on glucose metabolism and imparts an unclear advantage on cardiovascular risk profiles for long-term stable KTRs.

Nonimmunologic Factors Affecting Long-Term Outcomes of Deceased-Donor Kidney Transplant

OBJECTIVES

We investigated the impact of nonimmuno-logic factors on patient and graft survival after deceased-donor kidney transplant.

MATERIALS AND METHODS

All deceased-donor kidney transplants performed between January 2004 and December 2015 were included in our analyses. We used the independent t test to calculate significant differences between means above and below medians of various parameters.

RESULTS

All study patients (N = 205; 58.7% males) received antithymocyte globulin as induction therapy and standard maintenance therapy. Patients were free from infection, malignancy, and cardiac, liver, and pulmonary system abnormalities. Most patients (89.2%) were recipients of a first graft. Median patient age, weight, and cold ischemia time were 38 years, 65 kg, and 15 hours, respectively. Delayed graft function, diabetes mellitus, and hypertension occurred in 19.1%, 43.4%, and 77.9% of patients, respectively. The 1- and 5-year graft survival rates were 95% and 73.8%. Graft survival was not affected by donor or recipient sex or recipient diabetes or hypertension. However, graft survival was longer in patients who received no graft biopsy (8.2 vs 6.9 y; P = .027) and in those who had diagnosis of calcineurin inhibitor nephrotoxicity versus antibody-mediated rejection after biopsy (8.19 vs 3.66 y; P = .0047). Longer survival was shown with donors who had traumatic death versus cerebro-vascular accident (5.9 vs 5.3 y; P = .029) and donors below the 50th percentile in age (8.23 and 7.14 y; P = .0026) but less with donors who had terminal acute kidney injury (6.97 vs 8.16 y; P = .0062). We found a negative correlation between graft survival and donor age (P = .01) and 1-year serum creatinine (P = .01).

CONCLUSIONS

Donor age, cause of brain death, and acute kidney injury affected graft survival in our study cohort but not donor or recipient sex or posttransplant or donor blood pressure.

Factors predicting kidney delayed graft function among recipients of simultaneous liver-kidney transplantation: A single-center experience

BACKGROUND

Kidney delayed graft function (kDGF) remains a challenging problem following simultaneous liver and kidney transplantation (SLKT) with a reported incidence up to 40%. Given the scarcity of renal allografts, it is crucial to minimize the development of kDGF among SLKT recipients to improve patient and graft outcomes. We sought to assess the role of preoperative recipient and donor/graft factors on developing kDGF among recipients of SLKT.

METHODS

A retrospective review of 194 patients who received SLKT in the period from January 2004 to March 2017 in a single center was performed to assess the effect of preoperative factors on the development of kDGF.

RESULTS

Kidney delayed graft function was observed in 95 patients (49%). Multivariate analysis revealed that donor history of hypertension, cold static preservation of kidney grafts [versus using hypothermic pulsatile machine perfusion (HPMP)], donor final creatinine, physiologic MELD, and duration of delay of kidney transplantation after liver transplantation were significant independent predictors for kDGF. kDGF is associated with worse graft function and patient and graft survival.

CONCLUSIONS

Kidney delayed graft function has detrimental effects on graft function and graft survival. Understanding the risks and combining careful perioperative patient management, proper recipient selection and donor matching, and graft preservation using HPMP would decrease kDGF among SLKT recipients.

Renal Transplantation in Second-Level Private Hospitals in the State of Mexico

BACKGROUND

Kidney transplantation (KT) is the replacement therapy of choice in patients with end-stage renal disease (ESRD). Here we show a cohort of kidney transplant recipients from the period of May 1994 to May 2016 in 2 2nd-level private hospitals from the city of Toluca in the state of Mexico.

METHODS

We checked the clinical files of all the patients that received KT in the period of study.

RESULTS

We report 25 KT: 23 performed in Sanatorio Toluca and 2 in Sanatorio Florencia; 16 (64%) male and 9 (26%) female; mean age 36.03 ± 15.9 years (range, 10-66); 19 (76%) hemodialysis and 9 (24%) continuous ambulatory peritoneal dialysis before KT; ESRD etiology unknown in 16 (64%), diabetes in 5 (20%), IgA nephropathy in 2 (8%), and other in 2 (8%); living donors in 13 (52%) and deceased donors in 12 (48%); blood group 0+ in 18 (72%), A+ in 5 (20%), and B+ in 2 (8%); 21 (84%) with 0 and 4 (16%) with 1 HLA mismatch; and delayed graft function in 8 (32%), of which 7 were from deceased donors and 1 from a living donor. All 25 (100%) had a functional kidney at 1 year of follow-up. Immunosuppression regime consisted of multitarget maintenance therapy in all 25 (100%): cyclosporine in 18 (72%) and tacrolimus in 7 (28%). We used only methylprednisolone (MTP) as induction therapy. There were only 2 cases (8%) of acute rejection during the 1st 6 months of follow-up, and both responded to treatment with MTP.

CONCLUSIONS

KT is the treatment of choice for patients with ESRD. The obtained results using only an MTP induction regime are satisfactory, with graft and patient survivals of 100% in the 1st year of follow-up.

Is Brain-Dead Donor Fluid Therapy With Colloids Associated With Better Kidney Grafts?

OBJECTIVES

Fluid therapy is required to maintain perfusion to donor organs. Recent reviews on the choices of fluids have emphasized the safety of using crystalloids, as opposed to fluid therapy with colloids, which has been reported to be either unequivocally or potentially harmful in a number of studies on various patient populations. We aimed to analyze whether the type of fluid administered to donors is connected with kidney transplant outcomes.

MATERIALS AND METHODS

A total of 100 consecutive brain-dead multiorgan donors and their respective 181 kidney recipients were studied retrospectively. Data concerning donor fluid therapy, the characteristics of the donors and the recipients, and outcomes after kidney transplant were extracted from organ retrieval and patient records. Cases with early graft function were compared with cases with delayed graft function.

RESULTS

Donors had received both crystalloids and colloids in most cases (84%). Fluid therapy with crystalloids alone was more common among the 40 recipients with delayed (30%) than in the 103 recipients with early graft function (11%) (P = .005). Donor age, time on renal replacement therapy before transplant, and donor fluid therapy with crystalloids alone were independent risk factors for delayed graft function in multivariate analysis.

CONCLUSIONS

Our results suggest that donor fluid therapy including colloids could be beneficial instead of harmful compared with treatment with crystalloids alone. This finding needs to be evaluated in prospective studies.

Deceased donor renal transplantation: A single center experience

Deceased donor renal transplantation (DDRT) constitutes less than 5% of all kidney transplantats in India. A retrospective analysis of 173 deceased donor renal transplants performed in a public funded government hospital was done. Mean age of the recipients was 36 years (male:female ratio 2.4:1), and that of the donors was 32.3 years (male:female ratio 6:1). The cold ischemic time was 340 ± 170 minutes. Mean follow-up period was 36 months. Forty one patients died, 75% of them in the first post - transplant year. Sepsis and cardiovascular disease were the most common causes of death. Twenty two percent had acute rejection. There was no significant difference in the incidence in the rate of acute rejection, bacterial, fungal infections and death rate between the cohorts of induction and non induction immunosuppression. The patient and death censored graft survival at 1 year were 80 and 82.6% and at 5 years were 76 and 80% respectively.

Acute and Chronic Allograft Dysfunction in Kidney Transplant Recipients

Allograft dysfunction after a kidney transplant is often clinically asymptomatic and is usually detected as an increase in serum creatinine level with corresponding decrease in glomerular filtration rate. The diagnostic evaluation may include blood tests, urinalysis, transplant ultrasonography, radionuclide imaging, and allograft biopsy. Whether it occurs early or later after transplant, allograft dysfunction requires prompt evaluation to determine its cause and subsequent management. Acute rejection, medication toxicity from calcineurin inhibitors, and BK virus nephropathy can occur early or later. Other later causes include transplant glomerulopathy, recurrent glomerulonephritis, and renal artery stenosis.

Nighttime kidney transplantation is associated with less pure technical graft failure

Purpose

To minimize cold ischemia time, transplantations with kidneys from deceased donors are frequently performed during the night. However, sleep deprivation of those who perform the transplantation may have adverse effects on cognitive and psychomotor performance and may cause reduced cognitive flexibility. We hypothesize that renal transplantations performed during the night are associated with an increased incidence of pure technical graft failure.

Methods

A retrospective analysis of data of the Dutch Organ Transplant Registry concerning all transplants from deceased donors between 2000 and 2013 was performed. Nighttime surgery was defined as the start of the procedure between 8 p.m. and 8 a.m. The primary outcome measure was technical graft failure, defined as graft loss within 10 days after surgery without signs of (hyper)acute rejection.

Results

Of 4.519 renal transplantations in adult recipients, 1.480 were performed during the night. The incidence of pure technical graft failure was 1.0 % for procedures started during the night versus 2.6 % for daytime surgery (p = .001). In a multivariable model, correcting for relevant donor, recipient and graft factors, daytime surgery was an independent predictor of pure technical graft failure (p < .001).

Conclusions

Limitation of this study is mainly to its retrospective design, and the influence of some relevant variables, such as the experience level of the surgeon, could not be assessed. We conclude that nighttime surgery is associated with less pure technical graft failures. Further research is required to explore factors that may positively influence the performance of the surgical team during the night.

Center-level variation in the development of delayed graft function after deceased donor kidney transplantation

BACKGROUND

Patient-level risk factors for delayed graft function (DGF) have been well described. However, the Organ Procurement and Transplantation Network definition of DGF is based on dialysis in the first week, which is subject to center-level practice patterns. It remains unclear if there are center-level differences in DGF and if measurable center characteristics can explain these differences.

METHODS

Using the 2003 to 2012 Scientific Registry of Transplant Recipients data, we developed a hierarchical (multilevel) model to determine the association between center characteristics and DGF incidence after adjusting for known patient risk factors and to quantify residual variability across centers after adjustment for these factors.

RESULTS

Of 82,143 deceased donor kidney transplant recipients, 27.0% developed DGF, with a range across centers of 3.2% to 63.3%. A center's proportion of preemptive transplants (odds ratio [OR], 0.83; per 5% increment; 95% confidence interval [95% CI], 0.74-;0.93; P = 0.001) and kidneys with longer than 30 hr of cold ischemia time (CIT) (OR, 0.95; per 5% increment; 95% CI, 0.92-;0.98; P = 0.001) were associated with less DGF. A center's proportion of donation after cardiac death donors (OR, 1.12; per 5% increment; 95% CI, 1.03-;1.17; P < 0.001) and imported kidneys (OR, 1.06; per 5% increment; 95% CI, 1.03-;1.10; P < 0.001) were associated with more DGF. After patient-level and center-level adjustments, only 41.8% of centers had DGF incidences consistent with the national median and 28.2% had incidences above the national median.

CONCLUSION

Significant heterogeneity in DGF incidences across centers, even after adjusting for patient-level and center-level characteristics, calls into question the generalizability and validity of the current DGF definition. Enhanced understanding of center-level variability and improving the definition of DGF accordingly may improve DGF's utility in clinical care and as a surrogate endpoint in clinical trials.

Evaluation of the effects of recipient/donor gender on early/late postoperative renal graft functions by renal scintigraphy

OBJECTIVES

We discuss the effects of recipient/donor gender on renal allograft functions using scintigraphic parameters obtained 3 days after renal transplant and 1 year after transplant.

MATERIALS AND METHODS

This retrospective study included 76 renal allograft recipients (group one, 38 males; group two, 38 females). Patients underwent scintigraphic imaging with Tc-99m DTPA on postoperative day 3 and 1 year after transplant. We used the Hilson perfusion index, maximum renal activity/background activity, ratio of renal activity at 20 minutes to renal activity at 3 minutes, time-to-peak activity, and glomerular filtration rate to measure quantitative parameters.

RESULTS

On postoperative day 3, the Hilson perfusion index, maximum renal activity/background activity, the ratio of renal activity at 20 minutes to renal activity at 3 minutes, time-to-peak activity, and glomerular filtration rate values for male/female recipients were similar (P = .65, P = .77, P = .38, P = .10, P = .99). The gender of donors was compared with the above-mentioned scintigraphic parameters of the recipients, and no statistically significant differences were found (P = .24, P = .25, P = .44, P = .29, P = .13). At 1-year follow-up, values obtained from group 1 and group 2 recipients were similar. After 1 year, chronic rejection developed in 15.7% of group 1 recipients and in 10.5% of group 2 recipients; acute rejection developed in 21% of group 1 recipients and in 23.6% of group 2 recipients. There were no statistically significant differences between the occurrence of acute rejection and the gender of recipients or donors (P = 1.00, P = .45).

CONCLUSIONS

We observed no statistically significant differences between renal graft functions and gender of the recipients/donors during the early/late posttransplant period.

Pretransplantation erythropoiesis-stimulating agent hyporesponsiveness is associated with increased kidney allograft failure and mortality

BACKGROUND

Poor response to erythropoiesis-stimulating agents (ESA) is associated with morbidity and mortality among dialysis patients. It is unclear whether the risk associated with poor ESA response during dialysis extends beyond kidney transplantation. We examined pretransplantation ESA response and its effect on allograft failure and mortality.

METHODS

The cohort included all adult Medicare recipients from the U.S. Renal Data System who had received a kidney transplant during years 2000 to 2007 and had at least 6 months of hemodialysis immediately before transplantation. ESA hyporesponsiveness was primarily defined as a monthly ESA dose of 75,000 units or higher and hematocrit 33% or less for at least 3 consecutive months in the pretransplantation period. Crude and adjusted Cox proportional hazards models and Kaplan-Meier methods were used to estimate the effect of ESA hyporesponsiveness on allograft failure and all-cause mortality.

RESULTS

The study group consisted of 36,450 patients; 1004 exhibited hyporesponsiveness. The adjusted hazard ratios (95% confidence interval) for allograft failure and mortality after transplantation were 1.23 (1.10-1.42) and 1.61 (1.43-1.81), respectively, supporting that poor ESA response during hemodialysis is associated with adverse posttransplantation outcomes.

CONCLUSIONS

ESA hyporesponsiveness may be useful in identifying potential allograft recipients who are at high risk for subsequent morbidity and mortality and may benefit from more intensive pretransplantation and posttransplantation monitoring.

Is delayed graft function causally associated with long-term outcomes after kidney transplantation? Instrumental variable analysis

BACKGROUND

Although some studies have found an association between delayed graft function (DGF) after kidney transplantation and worse long-term outcomes, a causal relationship remains controversial. We investigated this relationship using an instrumental variables model (IVM), a quasi-randomization technique for drawing causal inferences.

METHODS

We identified 80,690 adult, deceased-donor, kidney-only transplant recipients from the Scientific Registry of Transplant Recipients between 1997 and 2010. We used cold ischemia time (CIT) as an instrument to test the hypothesis that DGF causes death-censored graft failure and mortality at 1 and 5 years after transplantation, controlling for an array of characteristics known to affect patient and graft survival. We compared our IVM results with a multivariable linear probability model.

RESULTS

DGF occurred in 27% of our sample. Graft failure rates at 1 and 5 years were 6% and 22%, respectively, and 1-year and 5-year mortality rates were 5% and 20%, respectively. In the linear probability model, DGF was associated with increased risk of both graft failure and mortality at 1 and 5 years (P<0.001). In the IVM, we found evidence suggesting a causal relationship between DGF and death-censored graft failure at both 1 year (13.5% increase; P<0.001) and 5 years (16.2% increase; P<0.001) and between DGF and mortality at both 1 year (7.1% increase; P<0.001) and 5 years (11.0% increase; P<0.01). Results were robust to exclusion of lower quality as well as pumped kidneys and use of a creatinine-based definition for DGF.

CONCLUSION

Instrumental variables analysis supports a causal relationship between DGF and both graft failure and mortality.

Delayed graft function is not associated with an increased incidence of renal allograft rejection

Delayed graft function (DGF) is considered as a risk factor for renal allograft rejection, but this association might be confounded by diagnostic biases (e.g., higher biopsy frequency in patients with DGF, inclusion of clinically diagnosed rejection episodes, and limited details on the rejection phenotype). This retrospective study including 329 deceased donor transplantations aimed to clarify a causal relationship between DGF and rejection. DGF occurred in 93/329 recipients (28%), whereas immediate graft function (IGF) in 236/329 recipients (72%). The percentage of patients with ≥1 allograft biopsy within the first year post-transplant was similar between the DGF and IGF group (96% vs. 94%; p=0.60). The cumulative one-yr incidence of biopsy-proven clinical (35% vs. 34%; p=0.62) and combined (sub)clinical rejection (58% vs. 60%; p=0.79) was not different between the two groups. Furthermore, there were no differences regarding rejection phenotypes/severities and time frame of occurrence. By multivariable Cox regression analysis, donor-specific HLA antibodies, younger recipient age, and immunosuppressive regimens were independent predictors for clinical rejection, while DGF was not. These results in an intermediate sized, but thoroughly investigated patient population challenge the concept that DGF is a risk factor for rejection and highlights the need for additional studies in this regard.

Slow early graft function: a neglected entity after renal transplantation

BACKGROUND

After renal transplantation, early graft function (EGF) can be divided into delayed graft function (DGF), slow graft function (SGF) and immediate graft function (IGF). DGF is well documented. However, when evaluating the long-term significance of early function, the literature shows conflicting definitions and inconsistent results. In addition, SGF, a new entity separate to DGF and IGF, is a recent and poorly understood development.

AIM

To investigate the risk factors for and the impact of poor EGF (PEGF) on long-term outcome.

METHODS

This retrospective study reviewed the records of local adult patients who underwent renal transplantation at the Groote Schuur Hospital (Cape Town, South Africa) between 2004 and 2008. EGF was divided according to day 5 serum creatinine into IGF (serum creatinine <150 µmol/l), SGF (serum creatinine >150 but <450 µmol/l) and DGF (serum creatinine >450 µmol/l or dialysis in the first week). DGF and SGF together comprised PEGF, with IGF alone representing good EGF (GEGF).

RESULTS

A total of 121 patients (77 men, 44 women; mean age 39 years, range 14-67) were included in the study. Eighteen were excluded due to nephrectomy (n = 8), death (n = 6) or loss to follow-up (n = 4) within the first year. Analysis of cadaveric donors showed no significant risk factors for PEGF with the exception of cold ischaemic time, which differed significantly between the GEGF and PEGF groups, with means of 12 and 16 h, respectively (p = 0.013). Considering both living and cadaveric grafts, the 1-year estimated glomerular filtration rate (eGFR) was significantly different between IGF and DGF (p = 0.038) as well as between IGF and SGF (p = 0.028), with no significant difference between SGF and DGF (p > 0.05). A comparison of the PEGF and GEGF groups yielded significantly different 1-year eGFR values (60 and 50 ml/min, respectively; p = 0.07), with PEGF also associated with a longer hospital stay (20 vs. 14 days; p = 0.00005). Acute rejection was independently associated with a lower 1-year eGFR (p = 0.028), but in the absence of rejection, GEGF and PEGF remained significantly different with regards to 1-year eGFR (p = 0.024).

CONCLUSIONS

SGF is not related to IGF but rather to DGF and should thus be regarded as a form of PEGF as opposed to GEGF. PEGF has a worse long-term outcome, and this indicates the need for increased efforts in its prevention and greater attention to its management.

Impact of early kidney resistance index on kidney graft and patient survival during a 5-year follow-up

BACKGROUND

Resistance index (RI) measured by Doppler sonography during the early post-transplant period reflects interstitial oedema within the transplanted kidney. We have prospectively analysed the relationship between RI measured shortly after kidney transplantation (KTx), patient and graft survival, as well as kidney graft function during a 5-year follow-up.

METHODS

RI was measured at the second to fourth day after KTx in 364 consecutive patients, who were divided into tertiles, according to baseline RI value (Group 1: RI < 0.73, Group 2: RI between 0.73 and 0.85 and Group 3: RI > 0.85). The kidney graft function [estimated glomerular filtration rate (eGFR)] during the follow-up period was calculated according to the Modification of Diet in Renal Disease formula.

RESULTS

During the 5-year follow-up period, 23 patients died (2.6 versus 6.5 versus 9.6% in RI tertiles, respectively) and 59 lost their kidney graft (12.1 versus 17.7 versus 18.4%, respectively). Survival analyses showed that the effect of RI was significant for a combined outcome [graft loss or death; hazard ratio (HR) = 10.88] and in relation to death, it was of borderline significance (HR = 45.3, P = 0.09). The effect of delayed graft function (DGF) was only significant on graft loss (HR = 1.73). eGFR in the highest tertile was lower than in the lowest tertile during the entire follow-up period.

CONCLUSIONS

High RI values measured in segmental arteries in the very early post-transplant period predict worse kidney graft function and increased risk of all-cause graft loss, including patient death in the 5-year follow-up period. (ii) The predictive value of RI is not completely independent from the adverse influence of DGF on the premature graft loss.

Primary nonfunction of renal allograft secondary to acute oxalate nephropathy

Primary nonfunction (PNF) accounts for 0.6 to 8% of renal allograft failure, and the focus on causes of PNF has changed from rejection to other causes. Calcium oxalate (CaOx) deposition is common in early allograft biopsies, and it contributes in moderate intensity to higher incidence of acute tubular necrosis and poor graft survival. A-49-year old male with ESRD secondary to polycystic kidney disease underwent extended criteria donor kidney transplantation. Posttransplant, patient developed delayed graft function (DGF), and the biopsy showed moderately intense CaOx deposition that persisted on subsequent biopsies for 16 weeks, eventually resulting in PNF. The serum oxalate level was 3 times more than normal at 85 μmol/L (normal <27 μmol/L). Allograft nephrectomy showed massive aggregates of CaOx crystal deposition in renal collecting system. In conclusion, acute oxalate nephropathy should be considered in the differential diagnosis of DGF since optimal management could change the outcome of the allograft.

Serum tissue inhibitor of metalloproteinases 1 (TIMP-1) predicts organ recovery from delayed graft function after kidney transplantation from donors after cardiac death

Donors after cardiac death (DCD) have recently become an important source of renal transplants to alleviate the shortage of renal grafts in kidney transplantation (KTx), although DCD kidneys often have complications associated with a delayed graft function (DGF). A microarray-based approach using renal biopsy samples obtained at 1 h after KTx from DCD identified the tissue inhibitor of metalloproteinases 1 (TIMP-1) gene as a potential predictive marker for DGF. The current study measured serum TIMP-1 in patients undergoing KTx and analyzed the time course after KTx. The average serum TIMP-1 level before KTx was 240 ± 10 ng/ml (n = 34). In patients undergoing KTx from a living donor (n = 23), the serum TIMP-1 levels showed no increase after KTx (POD1: 226 ± 12, POD2: 211 ± 12, and POD3: 195 ± 10 ng/ml), but in one case, the only patient who required post-KTx HD due to DGF, the level on POD1 was the highest among subjects (361 ng/ml). In contrast, patients undergoing KTx from DCDs (n = 11), the serum TIMP-1 levels increased rapidly after a KTx (POD1: 418 ± 32, POD2: 385 ± 42, and POD3: 278 ± 25 ng/ml). However, two patients who avoided post-KTx HD due to the immediate function of the graft did not show increased levels (<370 ng/ml) on either POD1 or POD2. The peak serum TIMP-1 values appeared to correlate to the post-KTx dialysis period. Furthermore, the increment of serum TIMP-1 on the early POD was found to be predictive of immediate or delayed function of the grafts. These data suggest that monitoring of serum TIMP-1 levels allow the prediction of graft recovery and the need for HD after a KTx from a DCD.

KDIGO clinical practice guideline for the care of kidney transplant recipients

The 2009 Kidney Disease: Improving Global Outcomes (KDIGO) clinical practice guideline on the monitoring, management, and treatment of kidney transplant recipients is intended to assist the practitioner caring for adults and children after kidney transplantation. The guideline development process followed an evidence-based approach, and management recommendations are based on systematic reviews of relevant treatment trials. Critical appraisal of the quality of the evidence and the strength of recommendations followed the Grades of Recommendation Assessment, Development, and Evaluation (GRADE) approach. The guideline makes recommendations for immunosuppression, graft monitoring, as well as prevention and treatment of infection, cardiovascular disease, malignancy, and other complications that are common in kidney transplant recipients, including hematological and bone disorders. Limitations of the evidence, especially on the lack of definitive clinical outcome trials, are discussed and suggestions are provided for future research.

Delayed graft function and the risk for death with a functioning graft

Delayed graft function (DGF) associates with an increased risk for graft failure, but its link with death with graft function (DWGF) is unknown. We used the US Renal Data System to assemble a cohort of all first, adult, deceased-donor kidney transplant recipients from January 1, 1998, through December 31, 2004. In total, 11,542 (23%) of 50,246 recipients required at least one dialysis session in the first week after transplantation. Compared with patients without DGF, patients with DGF were significantly more likely to die with a functioning graft (relative hazard 1.83 [95% confidence interval 1.73 to 1.93] and 1.53 [95% CI 1.45 to 1.63] for unadjusted and fully adjusted models, respectively). The risk for DWGF was slightly higher among women with DGF than among men. There was no significant heterogeneity among other subgroups, and the results were robust to sensitivity analyses. Acute rejection within the first year attenuated the DGF-DWGF association. Cardiovascular and infectious deaths were slightly more prevalent in the DGF group, but the relative hazards of cause-specific death were similar between DWGF and deaths during total follow-up. In summary, DGF associates with an increased risk for DWGF; the mechanisms underlying the negative impact of DGF require further study.

Acute rejection and chronic nephropathy: a systematic review of the literature

BACKGROUND

The risk of graft failure is the pivotal measure of effectiveness when evaluating immunosuppressive regimens for renal transplantation. However, to date most randomized trials of immunosuppressive therapy have had acute rejection as the primary endpoint for treatment comparisons. The objective here was to review the evidence relating acute rejection to renal graft function and graft survival.

METHODS

A systematic review of the published literature was undertaken. Studies were reviewed if they included the following: study populations of adults undergoing renal transplantation, endpoints of graft loss or survival, and quantitative data on the associations between acute rejection and graft function and survival.

RESULTS

Overall, 31 observational studies were included. The definition of acute rejection varied, and there was substantial heterogeneity in study design and methodology. In all but two studies, acute rejection was associated with an increased risk of graft loss-risk ratios ranged from 1.2 (no definition reported) to 10.5 (confirmed by biopsy and grade I Banff criteria). In addition, there was fairly strong evidence linking timing of acute rejection and graft survival and weaker evidence linking the number of episodes and graft survival. The heterogeneity between studies invalidated pooling of quantitative studies.

CONCLUSIONS

The weight of the evidence indicates that occurrence, timing, and number of acute rejection episodes are associated with increased risk of graft loss. Less is known about the severity of rejection, which is important because many immunosuppressive regimens lessen severity. Quantifying these relationships is a priority if acute rejection continues to be a surrogate trial endpoint.

Global Expression Profiles in 1-Hour Biopsy Specimens of Human Kidney Transplantation from Donors after Cardiac Death

Because of the worldwide shortage of renal grafts, kidney transplantation (KTx) from donors after cardiac death (DCD) is an alternative way to obtain KTx from brain-dead donors. Although the prognosis of DCD KTx is gradually improving, the graft often undergoes delayed graft function (DGF), rendering the control of DGF essential for post-KTx patient care. In an attempt to characterize etiology of DGF, genome-wide gene expression profiling was performed using renal biopsy samples performed at 1 h after KTx from DCD and the data were compared with those of KTx from living donors (LD). A total of 526 genes were differentially expressed between them. Genes involved in acute inflammation were activated, while metabolic pathways were consistently downregulated in DCD. These findings imply the inferior performance of the DCD grafts relative to LD grafts. Several genes were identified where the expression levels were correlated well with parameters indicating short- and long-term prognosis of the DCD patients. In addition, several genes encoding secretory proteins were identified that might reflect the performance of the graft and be potential noninvasive biomarkers. These data provide a good source for candidates of biomarkers that are potentially useful for the control of DGF.

Association between delayed graft function and allograft and patient survival: a systematic review and meta-analysis

BACKGROUND

Delayed graft function (DGF) is a common complication of renal transplantation. The short-term consequences of DGF are well known, but the long-term relationship between DGF and patient and graft survival is controversial in the published literature. We conducted a systematic review and meta-analysis to precisely estimate these relationships.

METHODS

We performed a literature search for original studies published through March 2007 pertaining to long-term (>6 months) outcomes of DGF. The primary outcome was graft survival. Secondary outcomes were patient survival, acute rejection and kidney function.

RESULTS

When compared to patients without DGF, patients with DGF had a 41% increased risk of graft loss (RR 1.41, 95% CI 1.27-1.56) at 3.2 years of follow-up. There was no significant relationship between DGF and patient survival at 5 years (RR 1.14, 95% CI 0.94-1.39). The mean creatinine in the non-DGF group was 1.6 mg/dl. Patients with DGF had a higher mean serum creatinine (0.66 mg/dl, 95% CI 0.57-0.74) compared to patients without DGF at 3.5 years of follow-up. DGF was associated with a 38% relative increase in the risk of acute rejection (RR 1.38, 95% CI 1.29-1.47).

CONCLUSION

The results of this meta-analysis emphasize and quantify the long-term detrimental association between DGF and important graft outcomes like graft survival, acute rejection and renal function. Efforts to prevent and treat DGF should be aggressively investigated in order to improve graft survival given the deficit in the number of kidney donors.

2202 kidney transplant recipients with 10 years of graft function: what happens next?

The ultimate goal of clinical transplantation is for the recipients to achieve long-term survival, with continuing graft function, that is equivalent to that of the age-matched general population. We studied subsequent outcome in kidney transplant recipients with 10 years of graft function. In all, 2202 kidney transplant recipients survived with graft function >10 years. For 10-year survivors, the actuarial 25-year patient survival rate for primary transplant living donor (LD) recipients was 57%; graft survival, 43%. For primary transplant deceased donor (DD) recipients, the actuarial 25-year patient survival rate was 39%; graft survival, 27%. The two major causes of late graft loss were death (with graft function) and chronic allograft nephropathy (tubular atrophy and interstitial fibrosis). The two major causes of death with function were cardiovascular disease (CVD) and malignancy. For nondiabetic recipients, the mean age at death with function from CVD was 54 +/- 13 years; for diabetic recipients, 53 +/- 7 years. By 20 years posttransplant, morbidity was common: >40% recipients had skin cancer (mean age for nondiabetic recipients, 53 +/- 13 years; for diabetics, 49 +/- 8 years), >10% had non-skin cancer (mean age for nondiabetic recipients, 53 +/- 16 years; for diabetics, 46 +/- 9 years), and >30% had CVD (mean age for nondiabetic recipients, 53 +/- 15 years; for diabetics, 47 +/- 9 years). We conclude that long-term transplant recipients have a high rate of morbidity and early mortality. As short-term results have improved, more focus is needed on long-term outcome.

Serum neutrophil gelatinase-associated lipocalin as a predictor of organ recovery from delayed graft function after kidney transplantation from donors after cardiac death

Because of a worldwide shortage of renal grafts, kidneys procured from donors after cardiac death (DCD) have recently become an important source of renal transplants. However, DCD kidneys often have complications with delayed graft function (DGF) and recipients require hemodialysis (HD) in the early period after kidney transplantation (KTx). This study evaluated serum NGAL as a potential specific parameter to predict early functional recovery of transplanted DCD kidneys. The average serum neutrophil gelatinase-associated lipocalin (NGAL) level in normal samples was 53 +/- 30 ng/ml, while that in patients with chronic renal failure requiring HD was markedly raised at 963 +/- 33 ng/ml. In patients undergoing a living-related KTx from a living donor (n=11), serum NGAL level decreased rapidly after KTx, and only in two cases, with serum NGAL levels over 400 ng/ml on postoperative day 1 (POD1), was HD required due to DGF. In contrast, all patients undergoing a KTx from a DCD (n=5) required HD due to DGF. Even in these cases, serum NGAL levels decreased rapidly several days after a KTx prior to the recovery of urine output and preceding the decrease in serum creatinine level. The pattern of decline in serum NGAL was biphasic, the decrease after the second peak indicating a functional recovery within the next several days. These data suggest that monitoring of serum NGAL levels may allow us to predict graft recovery and the need for HD after a KTx from a DCD.

Long-term renal outcomes after delayed graft function

Delayed graft function (DGF) describes dysfunction of the kidney allograft immediately after transplantation and is the most common complication in the immediate posttransplantation period. Although a standardized definition for DGF is lacking, it is most commonly defined as the need for dialysis within the first week after transplant. DGF is caused by a variety of factors related to the donor and recipient as well as organ procurement techniques. The occurrence of DGF affects both allograft and patient outcomes. In addition to prolonging hospital stay and increasing the costs associated with transplantation, DGF is associated with an increased incidence of acute rejection after transplantation and is associated with poorer long-term graft outcomes. Both immunologic and nonimmunologic mechanisms contribute to DGF. The risk factors for DGF that have been identified are reviewed as well as the impact of DGF on long-term outcomes.

Marked variation in the definition and diagnosis of delayed graft function: a systematic review

BACKGROUND

The term delayed graft function (DGF) is commonly used to describe the need for dialysis after receiving a kidney transplant. DGF increases morbidity after transplantation, prolongs hospitalization and may lead to premature graft failure. Various definitions of DGF are used in the literature without a uniformly accepted technique to identify DGF.

METHODS

We performed a systematic review of the literature to identify all of the different definitions and diagnostic techniques to identify DGF.

RESULTS

We identified 18 unique definitions for DGF and 10 diagnostic techniques to identify DGF.

CONCLUSIONS

The utilization of heterogeneous clinical criteria to define DGF has certain limitations. It will lead to delayed and sometimes inaccurate diagnosis of DGF. Hence a diagnostic test that identifies DGF reliably and early is necessary. Heterogeneity, in the definitions used for DGF, hinders the evolution of a diagnostic technique to identify DGF, which requires a gold standard definition. We are in need of a new definition that is uniformly accepted across the kidney transplant community. The new definition will be helpful in promoting better communication among transplant professionals and aids in comparing clinical studies of diagnostic techniques to identify DGF and thus may facilitate clinical trials of interventions for the treatment of DGF.

Steroid-free immunosuppression regime reduces both long-term cardiovascular morbidity and patient mortality in renal transplant recipients

The aim of this retrospective study was to assess the impact of steroid therapy on cardiovascular disease (CVD) and patient mortality, in 486 on-CsA renal transplant recipients, with a follow-up of 9.5 +/- 4.3 yr. Two hundred and one patients had their steroids permanently withdrawn at sixth month after transplantation (G1); 285 patients did not (G2) as they were unable (acute rejection after suspension) or unsuitable (because of clinical criteria or immunosuppressive protocols). The CVD considered were coronary artery disease diagnosed by angiography and myocardial infarction. G1 and G2 patients were well-matched regarding CVD risk factors, except for age (G1: 44 +/- 14 yr; G2: 40 +/- 12 yr; p < 0.003), incidence of male (G1: 62%; G2: 72%, p < 0.02) incidence of acute rejection (G1: 39%; G2: 83%, p < 0.0001). Both CVD and deaths occurring during the first year of transplantation were excluded from the analysis. At 20 yr, the cumulative probability of developing a CVD, was 3.8% in G1; 23.8% in G2 (p < 0.0005). Patient survival rate was 95% in G1; 62% in G2 (p < 0.003). Mortality caused by CVD was higher in G2 (4.2% vs. 0.5%; p < 0.03). The Cox analysis identified in steroid therapy the main independent risk factors for both CVD (hazard ratio 9.56 p < 0.0001) and patient mortality (hazard ratio 5.99, p < 0.0001). At 10th and 15th year after transplantation, the mean-daily dose of steroids was 4.2 mg. In the long-term, steroid therapy, even in low-doses, increases significantly both the rate of CVD and patient mortality. This retrospective study suggests that steroid-free regime should always be recommended for the prevention of post-transplant CVD. This relevant statement should be followed by a long-term prospective study.

Urine NGAL and IL-18 are predictive biomarkers for delayed graft function following kidney transplantation

Delayed graft function (DGF) due to tubule cell injury frequently complicates deceased donor kidney transplants. We tested whether urinary neutrophil gelatinase-associated lipocalin (NGAL) and interleukin-18 (IL-18) represent early biomarkers for DGF (defined as dialysis requirement within the first week after transplantation). Urine samples collected on day 0 from recipients of living donor kidneys (n = 23), deceased donor kidneys with prompt graft function (n = 20) and deceased donor kidneys with DGF (n = 10) were analyzed in a double blind fashion by ELISA for NGAL and IL-18. In patients with DGF, peak postoperative serum creatinine requiring dialysis typically occurred 2-4 days after transplant. Urine NGAL and IL-18 values were significantly different in the three groups on day 0, with maximally elevated levels noted in the DGF group (p < 0.0001). The receiver-operating characteristic curve for prediction of DGF based on urine NGAL or IL-18 at day 0 showed an area under the curve of 0.9 for both biomarkers. By multivariate analysis, both urine NGAL and IL-18 on day 0 predicted the trend in serum creatinine in the posttransplant period after adjusting for effects of age, gender, race, urine output and cold ischemia time (p < 0.01). Our results indicate that urine NGAL and IL-18 represent early, predictive biomarkers of DGF.

Kidney NGAL is a novel early marker of acute injury following transplantation

Acute kidney injury secondary to ischemia-reperfusion in renal allografts often results in delayed graft function. We tested the hypothesis that expression of neutrophil gelatinase-associated lipocalin (NGAL) is an early marker of acute kidney injury following transplantation. Sections from paraffin-embedded protocol biopsy specimens obtained at approximately one hour of reperfusion after transplantation of 13 cadaveric (CAD) and 12 living-related (LRD) renal allografts were examined by immunohistochemistry for expression of NGAL. The staining intensity was correlated with cold ischemia time, peak post-operative serum creatinine, and dialysis requirement. There were no differences between the LRD and CAD groups in age, gender or preoperative serum creatinine. Using a scoring system of 0 (no staining) to 3 (most intense staining), NGAL expression was significantly increased in CAD specimens (2.3+/-0.8 versus 0.8+/-0.7 in LRD, p<0.001). There was a strong correlation between NGAL staining intensity and cold ischemia time (R=0.87, p<0.001). Importantly, NGAL staining in these early CAD biopsies was strongly correlated with peak postoperative serum creatinine, which occurred days later (R=0.86, p<0.001). Four patients developed delayed graft function requiring dialysis during the first week posttransplantation; all of these patients displayed the most intense NGAL staining in their first protocol biopsies. We conclude that NGAL staining intensity in early protocol biopsies represents a novel predictive biomarker of acute kidney injury following transplantation.

One-Year Observation of Kidney Allograft Recipients Converted From Cyclosporine Microemulsion to Tacrolimus

The results from previous trials suggested that tacrolimus-based treatment in kidney transplantation was associated with a significantly lower incidence of acute rejection, and that cyclosporine microemulsion (CsA-Me)-treated patients converted to tacrolimus had numerically better 6-year graft survival than those remaining on CsA-Me. Death with a functioning graft and chronic graft nephropathy are the leading causes of late allograft loss. While standard cardiovascular risk factors are relevant, renal function itself becomes an important risk factor for cardiovascular morbidity and mortality in kidney transplantation patients. Expected benefits of the conversion from CsA-Me to tacrolimus with respect to renal function and cardiovascular status were the rationale for this observational study. Twenty one patients underwent conversion due to nephrotoxicity of cyclosporine (n = 18) or side effects (n = 3). Two out of 21 patients did not complete the study. The patient survival after 1 year was 100% in this group of patients; graft survival 94.7%. No cases of de novo diabetes mellitus were identified. Mean serum creatinine fell from 2.13 +/- 0.4 to 1.84 +/- 0.3 mg/dL (P < .02) and calculated glomerular filtration rate increased from 49.6 +/- 14.4 to 56.2 +/- 15.5 mL/min (P < .01). Total cholesterol decreased from 229.4 +/- 50.1 to 195.9 +/- 28.5 mg/dL (P < .005) and, low-density lipoprotein cholesterol from 125.7 +/- 37.3 to 104.4 +/- 22.6 mg/dL (P < .02). No significant changes in mean systolic or diastolic pressure or blood glucose levels were observed. The results of this observational study showed that in a group of patients with raised creatinine levels at entry, conversion to tacrolimus resulted in improved graft function and a more favorable cardiovascular risk profile.

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.

Outcome of nonheart-beating donor kidneys with prolonged delayed graft function after transplantation

Nonheart-beating donor (NHBD) kidneys are frequently associated with delayed graft function (DGF), with a deleterious effect on kidney function and allograft survival. The influence and the duration of DGF on the outcome of NHBD kidneys are assessed. All recipients of an NHBD kidney in the period 1993-2003 were reviewed. Excluded from analysis were patients with primary nonfunction (PNF). One hundred and five patients with a functioning NHBD graft were reviewed: 23 (22%) had immediate function (group 1), 40 (38%) had DGF < or = 2 weeks (group 2), 31 (30%) had DGF 15 days to 4 weeks (group 3) and 11 (10%) had DGF for > 4 weeks (group 4). Creatinine clearance at 3 months was higher in groups 1 and 2 versus group 4 (p = 0.015 and p = 0.006, respectively) and was higher in group 2 versus group 4, at 1 year (p = 0.01). Graft survival was 95%, 98%, 97% and 89%, respectively, at 1 year and 95%, 85%, 77% and 89%, respectively, at 5 years, which was not significantly different. The duration of DGF in NHB kidneys has a negative effect on creatinine clearance, but no effect on graft survival.

Cardiovascular risk and renal transplantation: post hoc analyses of the Assessment of Lescol in Renal Transplantation (ALERT) Study

BACKGROUND

Renal transplantation is associated with an increased risk for premature cardiovascular disease. We analyzed the data in the placebo arm of Assessment of Lescol in Renal Transplantation (ALERT) to improve our understanding of the relationship between cardiovascular risk factors and outcomes in this unique population.

METHODS

We performed Cox survival analysis for myocardial infarction, cardiac death, and noncardiac death in 1,052 patients recruited to the placebo arm of ALERT. These subjects were aged 30 to 75 years, had stable graft function at least 6 months after transplantation, had a serum total cholesterol level between 155 and 348 mg/dL (4 and 9 mmol/L), and were receiving cyclosporine-based immunosuppression.

RESULTS

The results confirm previous studies. In multivariate analysis, preexisting coronary heart disease (hazard ratio [HR], 3.69; P < 0.001), total cholesterol level (HR, 1.55 per 50 mg/dL; P = 0.0045), and prior acute rejection (HR, 2.36; P = 0.0023) were independent risk factors. Conversely, independent risk factors for cardiac death were age (HR, 1.58 per decade; P = 0.0033), diabetes (HR, 3.35; P = 0.0002), ST-T changes on the ECG (HR, 3.17; P = 0.0004), and serum creatinine level (HR, 2.65 per milligram per deciliter; P < 0.0001).

CONCLUSION

This analysis confirms that renal transplant recipients share risk factors for myocardial infarction and cardiac death with the general population. However, the pattern of risk factors and their relationship with outcomes is atypical, highlighting the unique nature of cardiovascular risk in transplant recipients.

Renal dysfunction is a strong and independent risk factor for mortality and cardiovascular complications in renal transplantation

Renal transplant recipients (RTR) have shortened life expectancy, primarily due to premature cardiovascular disease (CVD). Traditional CVD risk factors are highly prevalent. In addition, several non-traditional risk factors may contribute to the high risk. The aim of the study was to evaluate the effects of renal dysfunction on mortality and cardiovascular complications in 1052 placebo-treated patients of the Assessment of LEscol in Renal Transplantation (ALERT) trial. Follow-up was 5-6 years and endpoints included cardiac death, non-cardiovascular death, all-cause mortality, major adverse cardiac event (MACE), non-fatal myocardial infarction (MI) and stroke. The effects of serum creatinine at baseline on these endpoints were evaluated. Elevated serum creatinine in RTR was a strong and independent risk factor for MACE, cardiac, non-cardiovascular, and all-cause mortality, but not for stroke or non-fatal MI alone. Serum creatinine was associated with increased mortality and MACE, independent of established CVD risk factors. Graft loss resulted in increased incidences of non-cardiovascular death, all-cause mortality, MACE and non-fatal MI. In conclusion, elevated serum creatinine is a strong risk factor for all-cause, non-cardiovascular and cardiac mortality, and MACE, independent of traditional risk factors, but not for stroke or non-fatal MI alone.

Random blood glucose measurements and survival in nondiabetic renal transplant recipients

New-onset diabetes after renal transplantation (PTDM), a common consequence of immunosuppression, is associated with reduced patient survival. However, we know little about the impact of less marked changes in glucose homeostasis. To investigate this problem, we used data on average random blood glucose values during the first, second, and third months posttransplantation, derived from a cohort of 1186 patients who received their first cadaveric or living-donor transplant between 1984 and 2002. We analyzed both patient and death-censored graft survivals, subgrouping recipients into those with end-stage renal failure due to diabetic nephropathy versus those with PTDM versus patients without diabetes. We confirmed that PTDM patients display reduced survival following transplantation, but a long-term survival similar to that of patients with diabetic nephropathy and end-stage renal disease. However, among patients without diabetes, random blood glucose was also a strong determinant of outcome, even when in the low normal range. In contrast, neither the presence of diabetes nor random glucose levels showed a significant impact on graft survival. PTDM is recognized to be an important, potentially modifiable, risk factor for cardiovascular disease in transplant recipients. Our data suggest that there is a gradation of increased risk associated with impaired glycemic control that affects patients who do not have diabetes. These data support the need for improved understanding of glycemic control in transplant recipients and for more detailed screening for impaired glucose tolerance in this population.

Rapamycin inhibits human renal epithelial cell proliferation: Effect on cyclin D3 mRNA expression and stability

BACKGROUND

Recent data have suggested that rapamycin use during the initial period after transplantation is associated with prolonged delayed graft function (DGF). Because of the known effects of rapamycin in other cell types, we speculated that this action may be secondary to human renal epithelial cells (HRECs) inhibition of proliferation.

METHODS

Primary cultures of HRECs were incubated with various concentrations of rapamycin. Cell proliferation was evaluated by cytotoxicity assays. The cell cycle was analyzed by flow cytometry. Protein expression levels were assessed by Western blot. Cyclin D3 mRNA levels were measured by quantitative real-time polymerase chain reaction (PCR). The transcriptional activity of the cyclin D3 gene was evaluated using transient transfection.

RESULTS

Rapamycin exerted a significant concentration-dependent antiproliferative effect on growing HRECs by inhibiting the G(1) to S transition. The p70(S6) kinase pathway leading to cell cycle progression was found to be active, and low concentrations of rapamycin dramatically reduced p70(S6) kinase phosphorylation. Rapamycin completely inhibited the increase in cyclin D3 protein expression and mRNA accumulation induced by fetal calf serum, but did not affect cyclin E or cdk-inhibitor expression levels. This regulation of cyclin D3 protein expression is mainly due to a destabilization of its mRNA. Rapamycin reduced the mRNA half-life by 26% (4.8 +/- 1.3 hours vs. 6.5 +/- 1.0 hours, P < 0.001).

CONCLUSION

Rapamycin inhibits the proliferative response of HRECs to mitogenic stimuli, and causes cell cycle arrest in the early G(1) phase, not only by a nonspecific process due to inhibition of the p70(S6k) pathway, but also by a direct effect on cyclin D3 mRNA stability.

A Simulation Model to Investigate the Impact of Cardiovascular Risk in Renal Transplantation

Premature cardiovascular (CV) disease is the leading cause of death following renal transplantation and, as a consequence of death with a functioning graft, it is a major cause of graft loss. Renal transplant recipients have a high prevalence of CV risk factors that influence both patient and graft survival. We used data on the relationship between CV risk factors and graft and patient survivals to develop a discrete event simulation model to study the possible impact of CV risk factor reduction on transplant outcome. The simulation was based on a renal unit in a population that has the risk factor profile of patients from the West of Scotland. We studied the dynamic between patient numbers on the waiting list compared to the transplanted list. After establishing results pertinent to the renal unit, we investigated in what way potential changes to transplant policy affected patient numbers. These perturbations included changing the number of transplants performed, changing the incidence of acute rejection, and interventional policies where patients on the waiting list were selectively transplanted taking into account their CV risk factor profiles. Overall, the model predicts that reducing CV risk in the population with end-stage renal failure awaiting kidney transplantation will have comparable benefits to foreseeable developments in immunosuppression or attainable increases in transplant numbers. Moreover, addressing CV risk has benefits for all patients regardless of whether or not they ultimately receive a kidney transplant.

Conversion From Cyclosporine to Tacrolimus Results in Improved Creatinine But Does Not Alter Lipid Profile

INTRODUCTION

While cyclosporine and tacrolimus use results in similar renal graft survival, the side effect profiles of the drugs are substantially different. We examined the electrolyte and lipid alterations that occurred in our patient population following conversion from cyclosporine to tacrolimus.

METHODS

Data for electrolytes, lipid profile, and immunosuppression were analyzed from 98 patients with kidney or kidney-pancreas transplants who were converted from cyclosporine to tacrolimus between October 1994 and June 2001. Results, expressed as mean +/- SEM, were compared to baseline values using the Wilcoxon signed-rank test (P < .05 considered significant).

RESULTS

Among these patients, there were 56 men, 42 women, 75 primary transplants, 15 repeat transplants, and 26 multiorgan transplants. The mean time to tacrolimus conversion was 769 +/- 122 days. Creatinine, BUN, and glucose improved after conversion to tacrolimus. Surprisingly, cholesterol, low-density lipoproteins, and high-density lipoproteins levels were not significantly altered, although triglyceride levels demonstrated a significant difference at 1 year.

CONCLUSION

Significant improvements in creatinine and BUN were observed following conversion from cyclosporine to tacrolimus. While hypomagnesemia was also seen, there was surprisingly little alteration in lipid profile.