High Kidney Donor Profile Index Research Articles

#2822 Can KDPI estimate long-term graft survival in a cohort of Portuguese patients?

Abstract Background and Aims The Kidney Donor Profile Index (KDPI) was introduced in the United States in 2014 to support clinicians' decision-making regarding the acceptance or decline of potential donors. In Portugal, there is no valid stratification score to assist physicians in accepting or declining an organ offer. Our study aims to characterize a cohort of Portuguese kidney transplant recipients and donors and evaluate the correlation between KDPI and long-term graft survival. The results are interpreted considering the nuances of the Portuguese allocation system, which favors an age-matched donor-recipient allocation. Method We conducted an observational single-center retrospective cohort study, which included patients who received a deceased donor kidney transplant at our unit between January 2013 and December 2015. We excluded patients for whom the donor KDPI index was unavailable for retrieval. Besides the KDPI index, we collected data regarding the receptor's demographic, clinical, and immunological characteristics, as well as graft and recipient survival. The primary outcome was death-censored survival, and follow-up ended on the 31st of December 2023. The secondary outcome was survival with a functioning graft. Survival estimates were obtained using Kaplan-Meier curves. We performed univariate and multivariate survival analysis with log-rank tests and Cox proportional-hazards regression models. Results We selected 364 deceased-donor kidney recipients and 212 kidney donors. The mean KDPI was 60% and 53.3% of donors were classified as expanded criteria. The kidney recipients were predominantly male (68.4%), with a mean age of 50.16 years and an average of 4 HLA mismatches. Median follow-up was 102 months. Considering recipient characteristics according to pre-defined KDPI strata (≤ 20%, 21-85%, > 85%), recipients from higher KDPI were significantly older, with a mean age of 40.6, 48.8, and 61.1 years, respectively (p < 0.001), and had a higher average body mass index (p = 0.041). There were no significant differences regarding the number of HLA mismatches (p = 0.624) or the proportion of hypersensitized patients (p = 0.253) between classes. During follow-up, 16.8% patients presented graft failure and 9.9% died with a functioning graft. Cumulative death-censored graft survival at 5, 8, and 10 years was 87.7%, 87.1%, and 84.4% respectively. The cumulative percentage of patients living with a functioning graft at 5, 8, and 10 years was 83.6%, 76.7%, and 68.6%. Death-censored graft survival was lower in recipients of donors with higher KDPI (Fig. 1), although it did not reach statistical significance (p-value = 0.166). The number of HLA mismatches (p = 0.592) or the recipient's age (p = 0.513) did not significantly impact death-censored graft survival, whereas delayed graft function (DGF) was the variable with the strongest association in univariate analysis (p < 0.001). In a multivariate Cox regression model, KDPI (HR 1.02, p = 0.005) and DGF (HR 3.2, p < 0.001) correlated with graft loss, while older recipients (HR 0.971, p = 0.019) seemed to have a protective effect over death-censored survival. Patient survival with a functioning graft was significantly associated with KDPI strata (p = 0.008; Fig. 2), the recipient's age (p = 0.006), and DGF (p < 0.001) in univariate analysis. Considering KDPI kidneys ≥ 90%, 10-year cumulative death-censored survival was 67.9%. Conclusion In our sample, despite not reaching statistical significance, there was a trend for improved death-censored graft survival in patients with lower KDPI, which further emulates the results of other European cohorts. Nevertheless, the 10-year cumulative death-censored survival of higher KDPI kidneys (≥ 90%) was remarkable, showing that long-term acceptable outcomes can be achieved. The impact of KDPI on patient survival with a functioning graft is probably overestimated, given the bias introduced by the Portuguese matching system, which rewards an “old-for-old” donor-recipient allocation.

Consent for High-Kidney Donor Profile Index Kidneys: The Responsibility of Transplant Centers to Get it Right.

Consent for High-Kidney Donor Profile Index Kidneys: The Responsibility of Transplant Centers to Get it Right.

Can We Predict Kidney Graft Function and Graft Survival Using Hypothermic Machine Perfusion Parameters From Donors After Circulatory Death?

Hypothermic machine perfusion (HMP) reduces renal injury in donation after circulatory death donors with a high Kidney Donor Profile Index (KDPI). This study aims to characterize the correlation between KDPI, HMP parameters, and donor vitals during the withdrawal period in predicting short- and long-term graft outcomes. ANOVA with Tukey's honestly significant difference tests compared the relationship between average flow, average resistance, peak resistance, flow slope, and resistance slope on day 30, 1-y, and 3-y eGFR, and days of delayed graft function. Graft and recipient survival rates were assessed using Kaplan-Meier analysis. The data for 72 grafts were suitable for analysis. Kidneys with KDPI >50% had a significantly higher day 30, and 1-y posttransplant eGFR, if HMP average flow was >150 mL/min, or the average resistance was <0.15 mm Hg/mL/min, compared with kidneys with also KDPI >50% but had not achieved the same pump parameters. There were no significant differences in the Kaplan-Meier analysis, considering recipient or graft survival, regardless of the KPDI score with 3- or 5-y outcomes. Use of average resistance and average flow from a HMP, in conjunction with KDPI, may be predictive of the short- and long-term function of donation after circulatory death kidney transplants.

Characteristics of Delayed Graft Function and Long-Term Outcomes After Kidney Transplantation From Brain-Dead Donors: A Single-Center and Multicenter Registry-Based Retrospective Study.

Delayed graft function (DGF) after kidney transplantation is common and associated with worse graft outcomes. However, little is known about factors affecting graft survival post-DGF. We studied the association of cold ischemia time (CIT) and Kidney Donor Profile Index (KDPI) with the long-term outcomes of deceased brain-dead donor kidneys with and without DGF. Data from Finland (n = 2,637) and from the US Scientific Registry of Transplant Recipients (SRTR) registry (n = 61,405) was used. The association of KDPI and CIT with the graft survival of kidneys with or without DGF was studied using multivariable models. 849 (32%) kidneys had DGF in the Finnish cohort. DGF and KDPI were independent risk factors for graft loss, [HR 1.32 (95% CI 1.14-1.53), p < 0.001, and HR 1.01 per one point (95% CI 1.01-1.01), p < 0.001, respectively], but CIT was not, [HR 1.00 per CIT hour (95% CI 0.99-1.02), p = 0.84]. The association of DGF remained similar regardless of CIT and KDPI. The US cohort had similar results, but the association of DGF was stronger with higher KDPI. In conclusion, DGF and KDPI, but not CIT, are independently associated with graft survival. The association of DGF with worse graft survival is consistent across different CITs but stronger among marginal donors.

Therapeutic Hypothermia in Low-Risk Nonpumped Brain-Dead Kidney Donors

Delayed graft function in kidney-transplant recipients is associated with increased financial cost and patient burden. In donors with high Kidney Donor Profile Index whose kidneys are not pumped, therapeutic hypothermia has been shown to confer a protective benefit against delayed graft function. To determine whether hypothermia is superior to normothermia in preventing delayed graft function in low-risk nonpumped kidney donors after brain death. In a multicenter randomized clinical trial, brain-dead kidney donors deemed to be low risk and not requiring machine perfusion per Organ Procurement Organization protocol were prospectively randomized to hypothermia (34.0-35 °C) or normothermia (36.5-37.5 °C) between August 10, 2017, and May 21, 2020, across 4 Organ Procurement Organizations in the US (Arizona, Upper Midwest, Pacific Northwest, and Texas). The final analysis report is dated June 15, 2022, based on the data set received from the United Network for Organ Sharing on June 2, 2021. A total of 509 donors (normothermia: n = 245 and hypothermia: n = 236; 1017 kidneys) met inclusion criteria over the study period. Donor hypothermia (34.0-35.0 °C) or normothermia (36.5-37.5 °C). The primary outcome was delayed graft function in the kidney recipients, defined as the need for dialysis within the first week following kidney transplant. The primary analysis follows the intent-to-treat principle. A total of 934 kidneys were transplanted from 481 donors, of which 474 were randomized to the normothermia group and 460 to the hypothermia group. Donor characteristics were similar between the groups, with overall mean (SD) donor age 34.2 (11.1) years, and the mean donor creatinine level at enrollment of 1.03 (0.53) mg/dL. There was a predominance of Standard Criteria Donors (98% in each treatment arm) with similar low mean (SD) Kidney Donor Profile Index (normothermia: 28.99 [20.46] vs hypothermia: 28.32 [21.9]). Cold ischemia time was similar in the normothermia and hypothermia groups (15.99 [7.9] vs 15.45 [7.63] hours). Delayed graft function developed in 87 of the recipients (18%) in the normothermia group vs 79 (17%) in the hypothermia group (adjusted odds ratio, 0.92; 95% CI, 0.64-1.33; P = .66). The findings of this study suggest that, in low-risk non-pumped kidneys from brain-dead kidney donors, therapeutic hypothermia compared with normothermia does not appear to prevent delayed graft function in kidney transplant recipients. ClinicalTrials.gov Identifier: NCT02525510.

Quantifying the Effect of Consent for High-Kidney Donor Profile Index Deceased Donor Transplants in the United States.

Despite known benefits of kidney transplantation, including transplantation from donors with increased risk factors, many waitlisted candidates die prior to transplantation. Consent to receive donor kidneys with lower expected survival (e.g. kidney donor profile index [KDPI]>85%) is typically obtained at waitlist placement. The presumed benefit of consent to receive high-KDPI donor kidneys is increased likelihood and timeliness of donor offers for transplantation. However, the specific impact of consent on access to transplantation is unclear. Our aims were to evaluate the characteristics of candidates consenting to high-KDPI donor kidneys and the likelihood of receiving a deceased donor transplant (DDTX) over time based on consent. We used national Scientific Registry of Transplant Recipients data between 2015 and 2022(n=213,364). We evaluated the likelihood of consent using multivariable logistic models and time to DDTX with cumulative incidence plots accounting for competing risks and multivariable Cox models. Overall, high-KDPI consent was 41%, which was higher among candidates who were older, Black or Hispanic, had higher BMI, were diabetic, had vascular disease, and 12-48 months pre-listing dialysis time, with significant center-level variation. High-KDPI consent was associated with higher rates of DDTX(Adjusted Hazard Ratio=1.15,95% Confidence Interval=1.13,1.17) with no difference in likelihood of DDTX from donors with KDPI<85%. The effect of high-KDPI consent on higher rates of DDTx was higher among candidates ages >60 years and diabetic candidates and variable based on center characteristics. There is significant variation of consent for high-KDPI donor kidneys and higher likelihood of transplantation associated with consent.

Improved outcomes of kidney after liver transplantation after the implementation of the safety net policy.

The number of kidney after liver transplants (KALT) increased after the implementation of the United Network of Organ Sharing (UNOS) safety net policy, but the effects of the policy on KALT outcomes remain unknown. Using the UNOS database, we identified KALT between 60 and 365 days from liver transplant from January 1, 2010, to December 31, 2020. The main outcome was 1- and 3-year patient, liver, and kidney graft survival. Secondary outcomes included 6-month and 1-year acute rejection (AR) of liver and kidney, and 1-year kidney allograft function. Of the 256 KALT, 90 were pre-policy and 166 post-policy. Compared to pre-policy, post-policy 1- and 3-year liver graft survival was higher (54% and 54% vs. 86% and 81%, respectively, p <0.001), while 1- and 3-year kidney graft survival (99% and 75% vs. 92% and 79%, respectively, p =0.19), and 1- and 3-year patient survival (99% and 99% vs. 95% and 89%, respectively, p =0.11) were not significantly different. Subgroup analysis revealed similar trends in patients with and without renal failure at liver transplant. Liver AR at 6 months was lower post-policy (6.3% vs. 18.3%, p =0.006) but was similar (10.5% vs. 13%, p =0.63) at 1 year. Kidney AR was unchanged post-policy at 6 months and 1 year. Creatinine at 1 year did not differ post-policy versus pre-policy (1.4 vs. 1.3mg/dL, p =0.07) despite a higher proportion of deceased donors, higher Kidney Donor Profile Index, and longer kidney cold ischemia time post-policy ( p <0.05 for all). This 3-year follow-up after the 2017 UNOS policy revision demonstrated that the safety net implementation has resulted in improved liver outcomes for patients who underwent KALT with no increased AR of the liver or the kidney allografts.

The Effect of Perfusate Temperature on Delayed Graft Function in Deceased Donor Renal Transplantation.

Introduction: Renal allograft hypothermic machine perfusion results in a decreased incidence of delayed graft function compared with static cold storage. Ensuring perfusate temperatures remain within the target range of 4-10 °C may impact delayed graft function rates. Project Aims: To identify whether this target was achieved and, if not, whether higher perfusate temperature was associated with delayed graft function. Design: In this retrospective cohort study, transplanted grafts from deceased donors placed on hypothermic machine perfusion pump from June 2019 to August 2020 were analyzed. Measurements were recovered after 5, 15, 60, and 180 min of perfusion. Univariable and multivariable analyses were performed to identify predictors of delayed graft function. Results: A total of 113 grafts from 94 donors were analyzed. Of these, 21 (19%) developed delayed graft function. On univariable logistic regression, variables associated with delayed graft function included older donor age (OR 1.08, P = .002), higher Kidney Donor Profile Index score (OR 1.03, P = .024), and higher 5-min perfusate temperature (T5 min; OR 1.49, P = .014). A higher T5 min was also associated with delayed graft function in multivariable logistic regression models (OR 1.58, P = .005; OR 1.37, P = .08). Grafts with T5 min >10 °C were more likely to experience delayed graft function than those with T5 min <10 °C (OR 4.5, P = .006). Conclusion: Higher early perfusate temperature was an independent predictor of delayed graft function and may be due to inadequate cooling of the circuit prior to placing grafts on pump. Quality improvement initiatives targeting early perfusate temperatures of ≤10 °C may reduce delayed graft function incidence.

Comparative analysis of Basiliximab and Alemtuzumab induction therapies in blood type A2-to-B kidney transplantation: Impact on kidney function and de novo donor-specific HLA antibodies

PurposeBlood group B kidney transplant candidates have lower transplantation rates and longer waiting times compared to other blood groups. Kidney transplantation from blood group A2-to-B has offered a solution for these patients. This study aimed to investigate the impact of Basiliximab and Alemtuzumab induction therapies on kidney function and de novo donor-specific antibodies (DSA) in blood type A2-to-B kidney transplant recipients within the first 12 months of post-transplant. MethodsA retrospective analysis was conducted on 110 consecutive A2-to-B kidney transplant recipients between January 2015 and December 2022. Of these, 46 (41.8%) received Basiliximab, while 64 (58.2%) received Alemtuzumab as induction therapy. Demographics and comorbidities data were collected and compared between the two groups. Serum samples collected at 4- and 12-month intervals post-transplant were used to assess the presence of de novo DSA. Kidney allograft function was evaluated by monitoring serum creatinine levels and assessing Creatinine Clearance based on 24-h urine collection at various time points. ResultsDuring the follow-up period, 20.00% of patients who received Alemtuzumab developed de novo DSA, whereas none of the patients induced with Basiliximab developed de novo DSA (p = 0.038). Recipients who received Basiliximab were older (mean age = 72.00) and received higher Kidney Donor Profile Index (KDPI) kidneys (mean = 75) compared to those induced with Alemtuzumab (mean age = 58.00, mean KDPI = 49) (p < 0.001), with no significant difference observed in the last follow-up creatinine clearance or creatinine levels between the two groups (p = 0.28). ConclusionThe use of Basiliximab as induction immunosuppression in A2-to-B kidney transplant recipients is associated with a lower incidence of de novo HLA DSA formation without significant differences in overall renal function compared to Alemtuzumab.

Evaluating Cost-Effectiveness in Using High-Kidney Donor Profile Index Organs

A more granular donor kidney grading scale, the kidney donor profile index (KDPI), has recently emerged in contradistinction to the standard criteria donor/expanded criteria donor framework. In this paper, we built a Markov decision process model to evaluate the survival, quality-adjusted life years (QALY), and cost advantages of using high-KDPI kidneys based on multiple KDPI strata over a 60-month time horizon as opposed to remaining on the waiting list waiting for a lower-KDPI kidney. Data for the model were gathered from the Scientific Registry of Transplant Recipients and the United States Renal Data System Medicare parts A, B, and D databases. Of the 129,024 phenotypes delineated in this model, 65% of them would experience a survival benefit, 81% would experience an increase in QALYs, 87% would see cost-savings, and 76% would experience cost-savings per QALY from accepting a high-KDPI kidney rather than remaining on the waiting list waiting for a kidney of lower-KDPI. Classification and regression tree analysis (CART) revealed the main drivers of increased survival in accepting high-KDPI kidneys were wait time ≥30 months, panel reactive antibody (PRA) <90, age ≥45 to 65, diagnosis leading to renal failure, and prior transplantation. The CART analysis showed the main drivers of increased QALYs in accepting high-kidneys were wait time ≥30 months, PRA <90, and age ≥55 to 65.

Assessing Kidney Transplantation Using ECMO-Supported Donors Within a KDPI-Based Allocation System.

Organ donors supported by extracorporeal membrane oxygenation (ECMO) have historically been considered high-risk and are judiciously utilized. This study examines transplant outcomes using renal allografts from donors supported on ECMO for nondonation purposes. Retrospective review of the Gift of Life (Pennsylvania, New Jersey, Delaware) organ procurement organization database, cross-referenced to the Organ Procurement and Transplantation Network database, assessed kidney transplants using donors supported on venoarterial (VA) and venovenous (VV) ECMO for nondonation purposes. Transplants using VA- and VV-ECMO donors were compared with Kidney Donor Profile Index (KDPI)-stratified non-ECMO donors. Regression modeling of the entire ECMO and non-ECMO populations assessed ECMO as predictive of graft survival. Additional regression of the ECMO population alone assessed for donor features associated with graft survival. Seventy-eight ECMO donors yielded 128 kidney transplants (VA: 80, VV: 48). Comparing outcomes using these donors to kidney transplants using organs from KDPI-stratified non-ECMO donors, VA- and VV-ECMO donor grafts conferred similar rates of delayed graft function and posttransplant renal function to KDPI-matched non-ECMO counterparts. VA-ECMO kidneys demonstrated superior graft survival compared with the lowest-quality (KDPI 86%-100%) non-ECMO kidneys and similar graft survival to KDPI <85% non-ECMO kidneys. VV-ECMO showed inferior graft survival to all but the lowest-quality (KDPI 86%-100%) non-ECMO kidneys. VV-ECMO, but not VA-ECMO, was associated with increased risk of graft loss on multivariable regression (hazard ratios-VA: 1.02, VV: 2.18). Higher KDPI, advanced age, increased body mass index, hypertension, and diabetes were identified as high-risk features of ECMO donors. Kidney transplantation using appropriately selected ECMO donors can safely expand the donor pool. Ongoing studies are necessary to determine best practice patterns using kidneys from these donors.

Differences between Kidney Transplant Recipients from Deceased Donors with Diabetes Mellitus as Identified by Machine Learning Consensus Clustering.

Clinical outcomes of deceased donor kidney transplants coming from diabetic donors currently remain inconsistent, possibly due to high heterogeneities in this population. Our study aimed to cluster recipients of diabetic deceased donor kidney transplants using an unsupervised machine learning approach in order to identify subgroups with high risk of inferior outcomes and potential variables associated with these outcomes. Consensus cluster analysis was performed based on recipient-, donor-, and transplant-related characteristics in 7876 recipients of diabetic deceased donor kidney transplants from 2010 to 2019 in the OPTN/UNOS database. We determined the important characteristics of each assigned cluster and compared the post-transplant outcomes between the clusters. Consensus cluster analysis identified three clinically distinct clusters. Recipients in cluster 1 (n = 2903) were characterized by oldest age (64 ± 8 years), highest rate of comorbid diabetes mellitus (55%). They were more likely to receive kidney allografts from donors that were older (58 ± 6.3 years), had hypertension (89%), met expanded criteria donor (ECD) status (78%), had a high rate of cerebrovascular death (63%), and carried a high kidney donor profile index (KDPI). Recipients in cluster 2 (n = 687) were younger (49 ± 13 years) and all were re-transplant patients with higher panel reactive antibodies (PRA) (88 [IQR 46, 98]) who received kidneys from younger (44 ± 11 years), non-ECD deceased donors (88%) with low numbers of HLA mismatch (4 [IQR 2, 5]). The cluster 3 cohort was characterized by first-time kidney transplant recipients (100%) who received kidney allografts from younger (42 ± 11 years), non-ECD deceased donors (98%). Compared to cluster 3, cluster 1 had higher incidence of primary non-function, delayed graft function, patient death and death-censored graft failure, whereas cluster 2 had higher incidence of delayed graft function and death-censored graft failure but comparable primary non-function and patient death. An unsupervised machine learning approach characterized diabetic donor kidney transplant patients into three clinically distinct clusters with differing outcomes. Our data highlight opportunities to improve utilization of high KDPI kidneys coming from diabetic donors in recipients with survival-limiting comorbidities such as those observed in cluster 1.

Characterization of Transplant Center Decisions to Allocate Kidneys to Candidates With Lower Waiting List Priority

Allocation of deceased donor kidneys is meant to follow a ranked match-run list of eligible candidates, but transplant centers with a 1-to-1 relationship with their local organ procurement organization have full discretion to decline offers for higher-priority candidates and accept them for lower-ranked candidates at their center. To describe the practice and frequency of transplant centers placing deceased donor kidneys with candidates who are not the highest rank at their center according to the allocation algorithm. This retrospective cohort study used 2015 to 2019 organ offer data from US transplant centers with a 1-to-1 relationship with their local organ procurement organization, following candidates for transplant events from January 2015 to December 2019. Participants were deceased kidney donors with a single match-run and at least 1 kidney transplanted locally and adult, first-time, kidney-only transplant candidates receiving at least 1 offer for a locally transplanted deceased donor kidney. Data were analyzed from March 1, 2022 to March 28, 2023. Demographic and clinical characteristics of donors and recipients. The outcome of interest was kidney transplantation into the highest-priority candidate (defined as transplanted after zero declines for local candidates in the match-run) vs a lower-ranked candidate. This study assessed 26 579 organ offers from 3136 donors (median [IQR] age, 38 [25-51] years; 2903 [62%] men) to 4668 recipients. Transplant centers skipped their highest-ranked candidate to place kidneys further down the match-run for 3169 kidneys (68%). These kidneys went to a median (IQR) of the fourth- (third- to eighth-) ranked candidate. Higher kidney donor profile index (KDPI; higher score indicates lower quality) kidneys were less likely to go to the highest-ranked candidate, with 24% of kidneys with KDPI of at least 85% going to the top-ranked candidate vs 44% of KDPI 0% to 20% kidneys. When comparing estimated posttransplant survival (EPTS) scores between the skipped candidates and the ultimate recipients, kidneys were placed with recipients with both better and worse EPTS than the skipped candidates, across all KDPI risk groups. In this cohort study of local kidney allocation at isolated transplant centers, we found that centers frequently skipped their highest-priority candidates to place kidneys further down the allocation prioritization list, often citing organ quality concerns but placing kidneys with recipients with both better and worse EPTS with nearly equal frequency. This occurred with limited transparency and highlights the opportunity to improve the matching and offer algorithm to improve allocation efficiency.

RWD69 5-Year Graft Failure Outcomes Utilizing Kidneys with Higher Kidney Donor Profile Index Scores across Different Age Groups and Sex over a 10-Year Period

Several studies have shown that kidney transplantations with higher kidney donor profile index (KDPI) scores reduced mortality rates compared with remaining on dialysis or the waitlist hoping to receive a lower KDPI kidney. This study described the rate of 5-year graft failure of higher KDPI kidney transplants between sex and across different age groups.

RWD105 To What Extent Is Allocation of Higher KDPI Score Kidney Transplantation Occurring in the US?

To better serve patients on the kidney transplant waitlist in the US, current guidance recommends the expanded use of kidneys with higher Kidney Donor Profile Index (KDPI) score to offset the limited supply of standard criteria donor. This research aims to explore KDPI score and evaluate patient characteristics associated with higher KDPI Kidney Transplant (KT).

The Benefits of Preemptive Transplantation Using High-Kidney Donor Profile Index Kidneys.

The Kidney Donor Profile Index (KDPI) is a percentile score summarizing the likelihood of allograft failure: A KDPI ≥85% is associated with shorter allograft survival, and 50% of these donated kidneys are not currently used for transplantation. Preemptive transplantation (transplantation without prior maintenance dialysis) is associated with longer allograft survival than transplantation after dialysis; however, it is unknown whether this benefit extends to high-KDPI transplants. The objective of this analysis was to determine whether the benefit of preemptive transplantation extends to recipients of transplants with a KDPI ≥85%. This retrospective cohort study compared the post-transplant outcomes of preemptive and nonpreemptive deceased donor kidney transplants using data from the Scientific Registry of Transplant Recipients. 120,091 patients who received their first, kidney-only transplant between January 1, 2005, and December 31, 2017, were studied, including 23,211 with KDPI ≥85%. Of this cohort, 12,331 patients received a transplant preemptively. Time-to-event models for the outcomes of allograft loss from any cause, death-censored graft loss, and death with a functioning transplant were performed. Compared with recipients of nonpreemptive transplants with a KDPI of 0%-20% as the reference group, the risk of allograft loss from any cause in recipients of a preemptive transplant with KDPI ≥85% (hazard ratio [HR], 1.51; 95% confidence interval [CI], 1.39 to 1.64) was lower than that in recipients of nonpreemptive transplant with a KDPI ≥85% (HR, 2.39; 95% CI, 2.21 to 2.58) and similar to that of recipients of a nonpreemptive transplant with a KDPI of 51%-84% (HR, 1.61; 95% CI, 1.52 to 1.70). Preemptive transplantation is associated with a lower risk of allograft failure, irrespective of KDPI, and preemptive transplants with KDPI ≥85% have comparable outcomes with nonpreemptive transplants with KDPI 51%-84%.

413 Characteristics of Kidney Recipients of High Kidney Donor Profile Index Kidneys as Identified by Machine Learning Consensus Clustering

413 Characteristics of Kidney Recipients of High Kidney Donor Profile Index Kidneys as Identified by Machine Learning Consensus Clustering

Evaluation of Kidney Donor Risk Index/Kidney Donor Profile Index as Predictor Tools of Deceased-Donor Kidney Transplant Outcomes in a Greek Cohort.

The Kidney Donor Risk Index (KDRI) and Kidney Donor Profile Index (KDPI) have been developed to assess deceased-donor graft quality, although validation of their utility outside the USA remains limited. This single-center retrospective cohort study evaluated the ability of KDRI and KDPI to predict transplant outcomes in a Greek cohort. The efficacy of KDRI, KDPI, and donor's age in predicting death-censored graft failure was primarily assessed. Overall, 394 donors and 456 recipients were included. Death-censored graft survival was significantly worse with increasing KDRI (hazard ratio-HR: 2.21, 95% confidence intervals-CI: 1.16-4.22), KDPI (HR: 1.01, 95% CI: 1.00-1.02), and donor's age (HR: 1.03, 95% CI: 1.00-1.05). The unadjusted discriminative ability was similar for KDPI (C-statistic: 0.54) and donor's age (C-statistic: 0.52). The KDPI threshold of 85 was not predictive of graft failure (p-value: 0.19). Higher KDPI was linked to delayed graft function and worse kidney function, but not among expanded-criteria donor transplantations. No significant association was found between KDRI, KDPI, and patient survival. In conclusion, increasing KDRI and KDPI are linked to worse graft function, although their ability to discriminate long-term graft failure remains limited.

Knowing When to Ignore the Numbers: Single-Center Experience Transplanting Deceased Donor Kidneys with Poor Perfusion Parameters.

Hypothermic machine perfusion is frequently used in evaluating marginal kidneys with poor perfusion parameters (PPP) contributing to delays in kidney placement or discard. We examined outcomes in deceased donor kidney transplants with PPP compared with those with optimal perfusion parameters (OPP). We conducted a retrospective single-center cohort study from 2001 to 2021 comparing PPP (n = 91) with OPP (n = 598) deceased donor kidney transplants. PPP was defined as terminal flow ≤80 mL/min and terminal resistance ≥0.40 mmHg/mL/min. OPP was defined as terminal flow ≥120 mL/min and terminal resistance ≤0.20 mmHg/mL/min. Mean terminal flow was PPP 66 ± 16 vs OPP 149 ± 21 mL/min and resistance was PPP 0.47 ± 0.10 vs OPP 0.15 ± 0.04 mmHg/mL/min (both p < 0.001). Donor age, donation after cardiac death, and terminal serum creatinine levels were similar between groups. Mean Kidney Donor Profile Index was higher among PPP donors (PPP 65 ± 23% vs OPP 52 ± 27%, p < 0.001). The PPP transplant group had more females and lower weight and BMI. Delayed graft function was comparable (PPP 32% vs OPP 27%, p = 0.33) even though cold ischemia times trended toward longer in PPP kidneys (PPP 28 ± 10 vs OPP 26 ± 9 hours, p = 0.09). One-year patient survival (PPP 98% vs OPP 97%, p = 0.84) and graft survival (PPP 91% vs OPP 92%, p = 0.23) were equivalent. PPP did predict inferior overall and death-censored graft survival long-term (overall hazard ratio 1.63, 95% CI 1.19 to 2.23 and death-censored hazard ratio 1.77, 95% CI 1.15 to 2.74). At 1 year, the estimated glomerular filtration rate was higher with OPP kidneys (PPP 40 ± 17 vs OPP 52 ± 19 mL/min/1.73 m 2 , p < 0.001). Short-term outcomes in PPP kidneys were comparable to OPP kidneys despite higher Kidney Donor Profile Index and longer cold ischemia times, suggesting a role for increased utilization of these organs with careful recipient selection.

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

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