Ex-vivo ureteroscopy of deceased donor kidneys.
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ABSTRACT:
SUBMITTER: Machen GL
PROVIDER: S-EPMC5542832 | biostudies-other | 2017 Aug
REPOSITORIES: biostudies-other
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Project description:Waitlists are often used to ration scarce resources, but the trade-offs in designing these mechanisms depend on agents' preferences. We study equilibrium allocations under alternative designs for the deceased donor kidney waitlist. We model the decision to accept an organ or wait for a preferable one as an optimal stopping problem and estimate preferences using administrative data from the New York City area. Our estimates show that while some kidney types are desirable for all patients, there is substantial match-specific heterogeneity in values. We then develop methods to evaluate alternative mechanisms, comparing their effects on patient welfare to an equivalent change in donor supply. Past reforms to the kidney waitlist primarily resulted in redistribution, with similar welfare and organ discard rates to the benchmark first come first served mechanism. These mechanisms and other commonly studied theoretical benchmarks remain far from optimal. We design a mechanism that increases patient welfare by the equivalent of an 18.2 percent increase in donor supply.
| S-EPMC8294653 | biostudies-literature
Project description:Background and objectivesBiopsies taken at deceased donor kidney procurement continue to be cited as a leading reason for discard; however, the reproducibility and prognostic capability of these biopsies are controversial.Design, setting, participants, & measurementsWe compiled a retrospective, single-institution, continuous cohort of deceased donor kidney transplants performed from 2006 to 2009. Procurement biopsy information-percentage of glomerulosclerosis, interstitial fibrosis/tubular atrophy, and vascular disease-was obtained from the national transplant database. Using univariable, multivariable, and time-to-event analyses for death-censored graft survival, we compared procurement frozen section biopsy reports with reperfusion paraffin-embedded biopsies read by trained kidney pathologists (n=270). We also examined agreement for sequential procurement biopsies performed on the same kidney (n=116 kidneys).ResultsFor kidneys on which more than one procurement biopsy was performed (n=116), category agreement was found in only 64% of cases (κ=0.14). For all kidneys (n=270), correlation between procurement and reperfusion biopsies was poor: overall, biopsies were classified into the same category (optimal versus suboptimal) in only 64% of cases (κ=0.25). This discrepancy was most pronounced when categorizing percentage of glomerulosclerosis, which had 63% agreement (κ=0.15). Interstitial fibrosis/tubular atrophy and vascular disease had agreement rates of 82% (κ=0.13) and 80% (κ=0.15), respectively. Ninety-eight (36%) recipients died, and 56 (21%) allografts failed by the end of follow-up. Reperfusion biopsies were more prognostic than procurement biopsies (hazard ratio for graft failure, 2.02; 95% confidence interval, 1.09 to 3.74 versus hazard ratio for graft failure, 1.30; 95% confidence interval, 0.61 to 2.76), with procurement biopsies not significantly associated with graft failure.ConclusionsWe found that procurement biopsies are poorly reproducible, do not correlate well with paraffin-embedded reperfusion biopsies, and are not significantly associated with transplant outcomes.
| S-EPMC6302333 | biostudies-literature
Project description:Objective: To maximize the utilization of potential kidneys, improving perfusion and preservation techniques is necessary. Methods: We investigated the safety and efficacy of retrograde machine perfusion of kidneys from deceased donors. A total of 30 kidneys were included and all the grafts were preserved in the Kidney Transporter machines. A total of 15 kidneys that received retrograde perfusion (RP) were selected as the RP group (n = 15) and their counterparts received standard antegrade perfusion (AP) as the control group (n = 15). Results: All the recipients were followed up for 6 months. Renal resistance in the RP group remained stable during the perfusion. There was no primary nonfunction. No difference in the incidence of delayed graft function was found in both groups (3 in RP vs. 2 in AP, p = 0.62). The RP group had lower serum creatinine (RP vs. AP, 102.20 vs. 138.67, p = 0.05) and blood urea nitrogen (RP vs. AP, 6.44 vs. 8.71, p = 0.05) than that in the AP group at 6 months. Both the groups had comparable estimated glomerular filtration rate and cystatin C within 6 months. Conclusion: This novel technique may be an effective and safe alternative for kidney preservation.
| S-EPMC8718700 | biostudies-literature
Project description:Deceased donor kidney allocation follows a ranked match-run of potential recipients. Organ procurement organizations (OPOs) are permitted to deviate from the mandated match-run in exceptional circumstances. Using match-run data for all deceased donor kidney transplants (Ktx) in the US between 2015 and 2019, we identified 1544 kidneys transplanted from 933 donors with an OPO-initiated allocation exception. Most OPOs (55/58) used this process at least once, but 3 OPOs performed 64% of the exceptions and just 2 transplant centers received 25% of allocation exception Ktx. At 2 of 3 outlier OPOs these transplants increased 136% and 141% between 2015 and 2019 compared to only a 35% increase in all Ktx. Allocation exception donors had less favorable characteristics (median KDPI 70, 41% with history of hypertension), but only 29% had KDPI ≥ 85% and the majority did not meet the traditional threshold for marginal kidneys. Allocation exception kidneys went to larger centers with higher offer acceptance ratios and to recipients with 2 fewer priority points-equivalent to 2 less years of waiting time. OPO-initiated exceptions for kidney allocation are growing increasingly frequent and more concentrated at a few outlier centers. Increasing pressure to improve organ utilization risks increasing out-of-sequence allocations, potentially exacerbating disparities in access to transplantation.
| S-EPMC9081167 | biostudies-literature
Project description:BackgroundThe new deceased donor kidney allocation algorithm uses a Kidney Donor Profile Index (KDPI) based on donor characteristics to predict graft survival and divides kidneys into 4 quality groups (ie, KDPI-A, -B, -C, and -D). Pediatric kidneys constitute 10% to 12% of deceased donor kidneys. We hypothesized that KDPI would not accurately predict pediatric donor graft survival and superior predictive models could be created.MethodsScientific Registry of Transplant Recipients data for years 2000 to 2010 for transplants from child (<10 years) and adolescent (10-17 years inclusive) donors into first-time adult recipients were analyzed with graft failure as the principle outcome. Two novel indices, Child Donor Index (CDI) and Adolescent Donor Index (ADI), were developed using stepwise variable deletion to identify significant model covariates in a Cox Regression. Pediatric donor kidneys were then classified into the 4 quality groups based on both KDPI and CDI/ADI scores. The performance of the KDPI, CDI, and ADI models were compared with respect to the 4 quality groups defined by the new allocation system.ResultsThe KDPI did not effectively discriminate between quality groups (P > 0.05 for all but 1 comparison) in Kaplan-Meier survival analyses. The CDI and ADI included novel variables (eg, body mass index percentiles) and successfully discriminated between quality groups (P < 0.05 by log rank test). The Net Reclassification Index showed improvement when switching from KDPI to CDI and ADI, with values of 0.09 (P < 0.001) and 0.073 (P < 0.001), respectively.ConclusionsThe KDPI does not accurately predict pediatric kidney graft survival. Alternative indices can improve allocation efficiency.
| S-EPMC4940335 | biostudies-literature
Project description:BackgroundThe use of expanded criteria donor kidneys (ECD) had been associated with worse outcomes. Whole gene expression of pre-implantation allograft biopsies from deceased donor kidneys (DDKs) was evaluated to compare the effect of pulsatile pump preservation (PPP) vs. cold storage preservation (CSP) on standard and ECD kidneys.Methodology/principal findings99 pre-implantation DDK biopsies were studied using gene expression with GeneChips. Kidneys transplant recipients were followed post transplantation for 35.8 months (range = 24-62). The PPP group included 60 biopsies (cold ischemia time (CIT) = 1,367+/-509 minutes) and the CSP group included 39 biopsies (CIT = 1,022+/-485 minutes) (P<0.001). Donor age (42.0±14.6 vs. 34.1±14.2 years, P = 0.009) and the percentage of ECD kidneys (PPP = 35% vs. CSP = 12.8%, P = 0.012) were significantly different between groups. A two-sample t-test was performed, and probe sets having a P<0.001 were considered significant. Probe set level linear models were fit using cold ischemia time and CSP/PPP as independent variables to determine significant probe sets (P<0.001) between groups after adjusting for cold ischemia time. Thus, 43 significant genes were identified (P<0.001). Over-expression of genes associated with inflammation (CD86, CD209, CLEC4, EGFR2, TFF3, among others) was observed in the CSP group. Cell-to-cell signaling and interaction, and antigen presentation were the most important pathways with genes significantly over-expressed in CSP kidneys. When the analysis was restricted to ECD kidneys, genes involved in inflammation were also differentially up-regulated in ECD kidneys undergoing CSP. However, graft survival at the end of the study was similar between groups (P = 0.2). Moreover, the incidence of delayed graft function was not significant between groups.Conclusions/significanceInflammation was the most important up-regulated pattern associated with pre-implantation biopsies undergoing CSP even when the PPP group has a larger number of ECD kidneys. No significant difference was observed in delayed graft function incidence and graft function post-transplantation. These findings support the use of PPP in ECD donor kidneys.
| S-EPMC3335841 | biostudies-literature
Project description:Background and objectivesAn increasing number of patients on the waitlist for a kidney transplant indicates a need to effectively utilize as many deceased donor kidneys as possible while ensuring acceptable outcomes. Assessing regional and center-level organ utilization with regards to discard can reveal regional variation in suboptimal deceased donor kidney acceptance patterns stemming from perceptions of risk.Design, setting, participants, & measurementsWe created a weighted donor utilization index from a logistic regression model using high-risk donor characteristics and discard rates from 113,640 deceased donor kidneys procured for transplant from 2010 to 2016, and used it to examine deceased donor kidney utilization in 182 adult transplant centers with >15 annual deceased donor kidney transplants. Linear regression and correlation were used to analyze differences in donor utilization indexes.ResultsThe donor utilization index was found to significantly vary by Organ Procurement and Transplantation Network region (P<0.001), revealing geographic trends in kidney utilization. When investigating reasons for this disparity, there was no significant correlation between center volume and donor utilization index, but the percentage of deceased donor kidneys imported from other regions was significantly associated with donor utilization for all centers (rho=0.39; P<0.001). This correlation was found to be particularly strong for region 4 (rho=0.83; P=0.001) and region 9 (rho=0.82; P=0.001). Additionally, 25th percentile time to transplant was weakly associated with the donor utilization index (R2=0.15; P=0.03).ConclusionsThere is marked center-level variation in the use of deceased donor kidneys with less desirable characteristics both within and between regions. Broader utilization was significantly associated with shorter time to transplantation.
| S-EPMC6832051 | biostudies-literature
Project description:The number of kidneys obtained from deceased diabetic donors available for transplantation has increased >eightfold increase in the past 15 years. We assessed allograft outcomes associated with deceased diabetic donors and compared them with that of standard and extended criteria donors (ECD) in the UNOS data registry. We identified 1982 recipients of diabetic standard criteria donors over a 10-year period from 1995 through 2004. Both overall and death-censored survival of organs from diabetic standard criteria donors was significantly better than that of organs obtained from nondiabetic ECD while inferior to that from nondiabetic standard criteria donors. Compared with ECD donors, diabetic donors had lower serum creatinine, less cold ischemia and these kidneys were less likely to be pump-perfused. Recipients of diabetic kidneys were younger and less likely to experience delayed graft function compared with recipient of ECD kidneys. More recently, many diabetic donor kidneys have been given to diabetic recipients with early graft survival being similar to that among nondiabetic recipients. These findings demonstrate the potential to expand and to improve utilization of this resource without compromising outcomes for recipients. Improved, evidence-based evaluation and allocation of deceased diabetic donor kidneys is needed to optimize their use.
| S-EPMC3409306 | biostudies-literature
Project description:BackgroundDeceased donor kidneys are a scarce health resource, yet patient preferences for organ allocation are largely unknown. The aim of this study was to determine patient preferences for how kidneys should be allocated for transplantation.MethodsPatients on dialysis and kidney transplant recipients were purposively selected from two centres in Australia to participate in nominal/focus groups in March 2011. Participants identified and ranked criteria they considered important for deceased donor kidney allocation. Transcripts were thematically analysed to identify reasons for their rankings.ResultsFrom six groups involving 37 participants, 23 criteria emerged. Most agreed that matching, wait-list time, medical urgency, likelihood of surviving surgery, age, comorbidities, duration of illness, quality of life, number of organs needed and impact on the recipient's life circumstances were important considerations. Underpinning their rankings were four main themes: enhancing life, medical priority, recipient valuation, and deservingness. These were predominantly expressed as achieving equity for all patients, or priority for specific sub-groups of potential recipients regarded as more "deserving".ConclusionsPatients believed any wait-listed individual who would gain life expectancy and quality of life compared with dialysis should have access to transplantation. Equity of access to transplantation for all patients and justice for those who would look after their transplant were considered important. A utilitarian rationale based on maximizing health gains from the allocation of a scarce resource to avoid "wastage," were rarely expressed. Organ allocation organisations need to seek input from patients who can articulate preferences for allocation and advocate for equity and justice in organ allocation.
| S-EPMC3359260 | biostudies-literature
Project description: Not available
| S-EPMC8419126 | biostudies-literature