Donor Risk Index Research Articles

Performance of risk prediction models for post-liver transplant patient and graft survival over time.

Given liver transplantation organ scarcity, selection of recipients and donors to maximize post-transplant benefit is paramount. Several scores predict post-transplant outcomes by isolating elements of donor and recipient risk, including the donor risk index, Balance of Risk, pre-allocation score to predict survival outcomes following liver transplantation/survival outcomes following liver transplantation (SOFT), improved donor-to-recipient allocation score for deceased donors only/improved donor-to-recipient allocation score for both deceased and living donors (ID2EAL-D/-DR), and survival benefit (SB) models. No studies have examined the performance of these models over time, which is critical in an ever-evolving transplant landscape. This was a retrospective cohort study of liver transplantation events in the UNOS database from 2002 to 2021. We used Cox regression to evaluate model discrimination (Harrell's C) and calibration (testing of calibration curves) for post-transplant patient and graft survival at specified post-transplant timepoints. Sub-analyses were performed in the modern transplant era (post-2014) and for key donor-recipient characteristics. A total of 112,357 transplants were included. The SB and SOFT scores had the highest discrimination for short-term patient and graft survival, including in the modern transplant era, where only the SB model had good discrimination (C ≥ 0.60) for all patient and graft outcome timepoints. However, these models had evidence of poor calibration at 3- and 5-year patient survival timepoints. The ID2EAL-DR score had lower discrimination but adequate calibration at all patient survival timepoints. In stratified analyses, SB and SOFT scores performed better in younger (< 40 y) and higher Model for End-Stage Liver Disease (≥ 25) patients. All prediction scores had declining discrimination over time, and scores relying on donor factors alone had poor performance. Although the SB and SOFT scores had the best overall performance, all models demonstrated declining performance over time. This underscores the importance of periodically updating and/or developing new prediction models to reflect the evolving transplant field. Scores relying on donor factors alone do not meaningfully inform post-transplant risk.

Scoring donor lungs for graft failure risk: The Lung Donor Risk Index (LDRI)

Lung transplantation lags behind other solid organ transplants in donor lung utilization due, in part, to uncertainty regarding donor quality. We sought to develop an easy-to-use donor risk metric that, unlike existing metrics, accounts for a rich set of donor factors. Our study population consisted of n = 26 549 adult lung transplant recipients abstracted from the United Network for Organ Sharing Standard Transplant Analysis and Research file. We used Cox regression to model graft failure (GF; earliest of death or retransplant) risk based on donor and transplant factors, adjusting for recipient factors. We then derived and validated a Lung Donor Risk Index (LDRI) and developed a pertinent online application (https://shiny.pmacs.upenn.edu/LDRI_Calculator/). We found 12 donor/transplant factors that were independently predictive of GF: age, race, insulin-dependent diabetes, the difference between donor and recipient height, smoking, cocaine use, cytomegalovirus seropositivity, creatinine, human leukocyte antigen (HLA) mismatch, ischemia time, and donation after circulatory death. Validation showed the LDRI to have GF risk discrimination that was reasonable (C = 0.61) and higher than any of its predecessors. The LDRI is intended for use by transplant centers, organ procurement organizations, and regulatory agencies and to benefit patients in decision-making. Unlike its predecessors, the proposed LDRI could gain wide acceptance because of its granularity and similarity to the Kidney Donor Risk Index.

LIVER RETRANSPLANTATION: PROGNOSTIC SCORES AND RESULTS IN THE STATE OF PARANÁ.

Hepatic retransplantation is associated with higher morbidity and mortality when compared to primary transplantation. Given the scarcity of organs and the need for efficient allocation, evaluating parameters that can predict post-retransplant survival is crucial. This study aimed to analyze prognostic scores and outcomes of hepatic retransplantation. Data on primary transplants and retransplants carried out in the state of Paraná in 2019 and 2020 were analyzed. The two groups were compared based on 30-day survival and the main prognostic scores of the donor and recipient, namely Model for End-Stage Liver Disease (MELD), MELD-albumin (MELD-a), Donor MELD (D-MELD), Survival Outcomes Following Liver Transplantation (SOFT), Preallocation Score to Predict Survival Outcomes Following Liver Transplantation (P-SOFT), and Balance of Risk (BAR). A total of 425 primary transplants and 30 retransplants were included in the study. The main etiology of hepatopathy in primary transplantation was ethylism (n=140; 31.0%), and the main reasons for retransplantation were primary graft dysfunction (n=10; 33.3%) and hepatic artery thrombosis (n=8; 26.2%). The 30-day survival rate was higher in primary transplants than in retransplants (80.5% vs. 36.7%, p=0.001). Prognostic scores were higher in retransplants than in primary transplants: MELD 30.6 vs. 20.7 (p=0.001); MELD-a 31.5 vs. 23.5 (p=0.001); D-MELD 1234.4 vs. 834.0 (p=0.034); SOFT 22.3 vs. 8.2 (p=0.001); P-SOFT 22.2 vs. 7.8 (p=0.001); and BAR 15.6 vs. 8.3 (p=0.001). No difference was found in terms of Donor Risk Index (DRI). Retransplants exhibited lower survival rates at 30 days, as predicted by prognostic scores, but unrelated to the donor's condition.

Impact of Median MELD at Transplant Minus 3 National Policy on Quality of Transplanted Livers for Patients With and Without Hepatocellular Carcinoma.

Patients with hepatocellular carcinoma (HCC) have been overprioritized in the deceased donor liver allocation system. The United Network for Organ Sharing adopted a policy in May 2019 that limited HCC exception points to the median Model for End-Stage Liver Disease at transplant in the listing region minus 3. We hypothesized this policy change would increase the likelihood to transplant marginal quality livers into HCC patients. This was a retrospective cohort study of a national transplant registry, including adult deceased donor liver transplant recipients with and without HCC from May 18, 2017, to May 18, 2019 (prepolicy) to May 19, 2019, to March 1, 2021 (postpolicy). Transplanted livers were considered of marginal quality if they met ≥1 of the following: (1) donation after circulatory death, (2) donor age ≥70, (3) macrosteatosis ≥30% and (4) donor risk index ≥95th percentile. We compared characteristics across policy periods and by HCC status. A total of 23 164 patients were included (11 339 prepolicy and 11 825 postpolicy), 22.7% of whom received HCC exception points (prepolicy versus postpolicy: 26.1% versus 19.4%; P = 0.03). The percentage of transplanted donor livers meeting marginal quality criteria decreased for non-HCC (17.3% versus 16.0%; P < 0.001) but increased for HCC (17.7% versus 19.4%; P < 0.001) prepolicy versus postpolicy. After adjusting for recipient characteristics, HCC recipients had 28% higher odds of being transplanted with marginal quality liver independent of policy period (odds ratio: 1.28; confidence interval, 1.09-1.50; P < 0.01). The median Model for End-Stage Liver Disease at transplant in the listing region minus 3 policy limited exception points and decreased the quality of livers received by HCC patients.

Retrospective Analysis of the Impact of High- and Low-Quality Donor Livers for Patients withHigh-Acuity Illness.

BACKGROUND Patients with high-acuity liver failure have increased access to marginal and split liver options, owing to historically high waitlist mortality rates. While most research states that donor liver quality has no impact on patients with high-acuity illness, there have been inconsistencies in recent research on how liver quality impacts post-transplant outcomes for these patients. We aimed to quantify donor liver quality with various post-transplantation patient outcomes for patients with high-acuity illness. MATERIAL AND METHODS Using the liver donor risk index (LDRI), model for end stage liver disease (MELD), and clinically relevant recipient factors, we used multivariate logistic regression to analyze how donor liver quality affects varying measures of patient outcomes for 9923 high-acuity patients from June 18, 2013, to June 18, 2022. RESULTS Using LDRI, high-quality livers had a significant protective impact on high-acuity patient mortality, compared with low-quality livers (OR=0.695 [0.549, 0.879], P=0.002). High-quality livers also had significant impact on graft survival (OR=0.706 [0.558, 0.894], P=0.004). Two sensitivity patient mortality analyses, excluding patients with status 1A and hepatocellular carcinoma, showed significant protective findings for high-quality livers. High-quality livers had insignificant outcomes on long-term survivor mortality, length of hospitalization, and primary non-function outcomes, compared with low-quality donor livers. CONCLUSIONS While our findings suggest donor quality has an impact on high-acuity patient outcomes, these findings indicate further research is needed in intent-to-treat analysis on clinical offer data to provide a clearer finding of how donor quality affects patients with high-acuity illness.

An external validation of the Kidney Donor Risk Index in the UK transplant population in the presence of semi-competing events

BackgroundTransplantation represents the optimal treatment for many patients with end-stage kidney disease. When a donor kidney is available to a waitlisted patient, clinicians responsible for the care of the potential recipient must make the decision to accept or decline the offer based upon complex and variable information about the donor, the recipient and the transplant process. A clinical prediction model may be able to support clinicians in their decision-making. The Kidney Donor Risk Index (KDRI) was developed in the United States to predict graft failure following kidney transplantation. The survival process following transplantation consists of semi-competing events where death precludes graft failure, but not vice-versa.MethodsWe externally validated the KDRI in the UK kidney transplant population and assessed whether validation under a semi-competing risks framework impacted predictive performance. Additionally, we explored whether the KDRI requires updating. We included 20,035 adult recipients of first, deceased donor, single, kidney-only transplants between January 1, 2004, and December 31, 2018, collected by the UK Transplant Registry and held by NHS Blood and Transplant. The outcomes of interest were 1- and 5-year graft failure following transplantation. In light of the semi-competing events, recipient death was handled in two ways: censoring patients at the time of death and modelling death as a competing event. Cox proportional hazard models were used to validate the KDRI when censoring graft failure by death, and cause-specific Cox models were used to account for death as a competing event.ResultsThe KDRI underestimated event probabilities for those at higher risk of graft failure. For 5-year graft failure, discrimination was poorer in the semi-competing risks model (0.625, 95% CI 0.611 to 0.640;0.611, 95% CI 0.597 to 0.625), but predictions were more accurate (Brier score 0.117, 95% CI 0.112 to 0.121; 0.114, 95% CI 0.109 to 0.118). Calibration plots were similar regardless of whether the death was modelled as a competing event or not. Updating the KDRI worsened calibration, but marginally improved discrimination.ConclusionsPredictive performance for 1-year graft failure was similar between death-censored and competing event graft failure, but differences appeared when predicting 5-year graft failure. The updated index did not have superior performance and we conclude that updating the KDRI in the present form is not required.

Evaluation of Opening Offers Early for Deceased Donor Kidneys at Risk of Nonutilization.

Reducing nonutilization of kidneys recovered from deceased donors is a current policy concern for kidney allocation in the United States. The likelihood of nonutilization is greater with a higher kidney donor risk index (KDRI) offer. We examine how opening offers for organs with KDRI >1.75 to the broader waitlist at varying points of time affects usage rates. We simulate kidney allocation using data for January 2018 to June 2019 from Organ Procurement and Transplantation Network. For the simulation experiment, allocation policy is modified so that KDRI >1.75 organs are offered to all local candidates (same donation service area) after a set amount of cold time simultaneously. Open offers to candidates nationally are similarly examined. Simulation results ( n =50 replications) estimate that opening offers locally for KDRI >1.75 after 10 hours yields a nonutilization rate of 38% (range: 35%-42%), less than the prevailing rate of 55% of KDRI >1.75 kidneys. Opening offers after 5 hours yields 30% (range: 26%-34%), reducing the prevailing nonutilization rate by 45%. Opening offers nationally after 10 and 5 hours yields nonutilization rates of 11% (range: 8%-15%) and 6% (range: 4%-9%) for KDRI >1.75 kidneys, respectively. Simulation findings indicate that opening offers and adjusting their timing can significantly reduce nonutilization of high-KDRI kidneys.

Establishing a HOPE Program in a Real-life Setting: A Brazilian Case Series.

Although hypothermic oxygenated perfusion (HOPE) improves posttransplant outcomes, setting up machine perfusion programs may be subjected to specific obstacles under different conditions. This study aims to describe the establishment of HOPE in a real-life setting in Brazil. Extended criteria donors in donation after brain death organs preserved by HOPE were accepted for higher-risk candidates needing expedited transplantation, perceived as those who would benefit most from the technique because of its limited availability. Extended criteria donors was defined by the Eurotransplant criteria. High-risk transplant candidates were characterized by suboptimal surgical conditions related to the recipient or the procedure. Six HOPE-preserved grafts were transplanted from February 2022 to August 2022. The mean donor risk index was 1.7 (SD 0.5). One organ was severely steatotic, and 3 had an anticipated cold ischemia time above 12 h. Recipients' mean model for end-stage liver disease was 28.67 (SD 6.79), with 1 case of retransplant, 1 of refractory ascites, and 1 of acute-on-chronic liver failure. The mean cold ischemia time was 5 h 42 min (SD 82 min), HOPE 6 h 3 min (SD 150 min), and total preservation time 11 h 46 min (SD 184 min). No case had early allograft dysfunction. The mean length of hospital stay was 10 d with 100% graft and patient survival and no ischemic cholangiopathies at a median follow-up of 15 mo (min 12, max 18). Costs and country-specific legal regulations for device utilization were the major hurdles to implementing the program. We presented a pathway to introduce and rationalize the use of HOPE in a scenario of challenging donor-recipient matching with good results. These findings may aid in implementing machine perfusion programs, especially in settings with limited resources or complex transplant logistics.

Kidney Survival Impact of Delayed Graft Function Depends on Kidney Donor Risk Index: A Single-Center Cohort Study.

Delayed graft function (DGF) is a significant challenge in renal transplantation, particularly with deceased donors, necessitating early postoperative dialysis. The prolonged effects of medium- and long-term DGF remain uncertain, marked by contradictory graft survival outcomes. This incongruity might arise from the inherent graft resilience and regenerative capacity during transplantation. This study investigates DGF's impact on graft survival, focusing on grafts displaying favorable (KDRI < 1) and unfavorable outcomes (KDRI ≥ 1). In this retrospective cohort study (January 2015-December 2019), we assessed kidney transplants at our center, excluding multiorgan simultaneous cases, primary non-functioning grafts, and surgical complications causing graft loss. Patients were categorized into DGF presence or absence groups. Univariate and multivariate analyses, alongside propensity score matching (PSM), were performed. The study encompassed 322 deceased donor kidneys, with 83 encountering DGF. Grafts with higher KDRI indices (KDRI ≥ 1) and DGF exhibited a notably increased graft loss risk (HR: 4.17, 95% CI: 1.93-9.01). However, lower-KDRI donor grafts displayed no significant disparities between the DGF and non-DGF groups. Delayed graft function (DGF) development significantly contributes to graft loss in kidney transplants, particularly in grafts with KDRI ≥ 1.

Graft and Patient Survival in Kidney Transplant with Deceased Donor Using KDRI (Kidney Donor Risk Index), KDPI (Kidney Donor Profile Index), and EPTS (Estimated Post-Transplant Survival) in Colombia.

BACKGROUND EPTS (Estimated Post-Transplant Survival), KDRI (Kidney Donor Risk Index), and KDPI (Kidney Donor Profile Index) were developed aiming to ameliorate donor-recipient longevity matching in kidney transplants. They are based on a prediction model made using the United States population; evidence of their use outside EEUU remains limited. The aim of this study was to describe the quality of deceased-donor kidneys and to determine recipient and graft survival, glomerular filtration rate, and incidence of delayed graft function in renal transplantation according to these indices in Cali, Colombia. MATERIAL AND METHODS In this historical cohort study, Kaplan-Meier method was used to analyze survival of recipient and graft according to the values of the indices categorized by quintiles. Glomerular filtration rate and incidence of delayed graft function were also analyzed according to KDRI and KDPI. RESULTS We included 380 patients. Medians of EPTS, KDRI, and KDPI were 24% (IQR 9-60), 0.8 (IQR 0.71-0.99), and 27% (IQR 13-49), respectively. Two-year survival was 97.8% in recipients with EPTS ≤20% and it decreased with higher values of the index. Recipient and graft survival were lower for all periods when donors had KDPI >80%. Incidence of delayed graft function was higher in patients whose donors had KDPI ≥60% (44% vs 21%). Glomerular filtration rate decreased with the highest values of KDPI for all periods. CONCLUSIONS Our study represents the initial evaluation of the usefulness of these indices in Colombia. Our results suggest that KDRI, KDPI, and EPTS may serve as valuable tools for kidney allocation in our setting. Further research with larger sample sizes is necessary to validate these indices in our population.

Routine End-ischemic Hypothermic Oxygenated Machine Perfusion in Liver Transplantation from Donors After Brain Death: A Randomized Controlled Trial.

To assess whether end-ischemic hypothermic oxygenated machine perfusion (HOPE) is superior to static cold storage (SCS) in preserving livers procured from donors after brain death (DBD). There is increasing evidence of the benefits of HOPE in liver transplantation, but predominantly in the setting of high-risk donors. In this randomized clinical trial, livers procured from DBDs were randomly assigned to either end-ischemic dual HOPE for at least 2h or SCS ( 1:3 allocation ratio). The Model for Early Allograft Function (MEAF) was the primary outcome measure. The secondary outcome measure was 90-day morbidity. (ClinicalTrials. gov, NCT04812054). Of the 104 liver transplantations included in the study, 26 were assigned to HOPE and 78 to SCS. Mean MEAF was 4.94 and 5.49 in the HOPE and SCS group (P=0.24), respectively, with the corresponding rates of MEAF >8 of 3.8% (1/26) and 15.4% (12/78; P=0.18). Median comprehensive complication index was 20.9 after transplantations with HOPE and 21.8 after transplantations with SCS (P=0.19). Transaminases activity, bilirubin concentration, and international normalized ratio were similar in both the groups. In the case of donor risk index >1.70, HOPE was associated with significantly lower mean MEAF (4.92 vs. 6.31; P=0.037) and lower median comprehensive complication index (4.35 vs. 22.6; P=0.050). No significant differences between HOPE and SCS were observed for lower donor risk index values. Routine use of HOPE in DBD liver transplantations does not seem justified as the clinical benefits are limited to high-risk donors.

Pancreas Rejection in the Artificial Intelligence Era: New Tool for Signal Patients at Risk.

Pancreas transplantation is currently the only treatment that can re-establish normal endocrine pancreatic function. Despite all efforts, pancreas allograft survival and rejection remain major clinical problems. The purpose of this study was to identify features that could signal patients at risk of pancreas allograft rejection. We collected 74 features from 79 patients who underwent simultaneous pancreas-kidney transplantation (SPK) and used two widely-applicable classification methods, the Naive Bayesian Classifier and Support Vector Machine, to build predictive models. We used the area under the receiver operating characteristic curve and classification accuracy to evaluate the predictive performance via leave-one-out cross-validation. Rejection events were identified in 13 SPK patients (17.8%). In feature selection approach, it was possible to identify 10 features, namely: previous treatment for diabetes mellitus with long-term Insulin (U/I/day), type of dialysis (peritoneal dialysis, hemodialysis, or pre-emptive), de novo DSA, vPRA_Pre-Transplant (%), donor blood glucose, pancreas donor risk index (pDRI), recipient height, dialysis time (days), warm ischemia (minutes), recipient of intensive care (days). The results showed that the Naive Bayes and Support Vector Machine classifiers prediction performed very well, with an AUROC and classification accuracy of 0.97 and 0.87, respectively, in the first model and 0.96 and 0.94 in the second model. Our results indicated that it is feasible to develop successful classifiers for the prediction of graft rejection. The Naive Bayesian generated nomogram can be used for rejection probability prediction, thus supporting clinical decision making.

Association between Kidney Donor Risk Index, kidney graft function and histological changes in early post-transplant graft biopsy.

Proper assessment of donor organ quality is crucial for optimal kidney allocation and best long-term outcomes. The aim of this study was to analyze the association between the Kidney Donor Risk Index (KDRI) and histological parameters in early post-transplant graft biopsy in a Polish cohort of kidney transplant recipients. In 418 consecutive kidney transplant recipients, a histological evaluation of very early [at median 11 (9-13) post-transplant day] protocol core needle biopsy was performed and analyzed according to the Banff classification. Subjects were divided into quartiles of the KDRI value. Kidney graft function, patient and graft survival were also analyzed over a median follow-up period of 44 (26-56) months. There was a significant trend toward greater intensity of chronic histology changes along the KDRI quartiles (χ2=20.8; P<.001), including interstitial fibrosis, tubular atrophy, mesangial matrix increase and arteriolar hyalinosis. Stepwise multivariate regression analysis revealed that only higher KDRI value independently increased the severity of chronic graft injury (rpartial=0.340, P<.001). KDRI values were valuable in the determination of both early and long-term graft function. The KDRI values correlate with chronic histological changes found in early post-implantation kidney biopsies and can also be helpful in the prediction of graft outcome.

Pasireotide Versus Octreotide in Preventing Complications After Simultaneous Pancreas-Kidney Transplantation.

In elective pancreatic surgery, somatostatin-analogues pasireotide and octreotide are variably used to reduce postoperative complications, but knowledge on their role in pancreas transplantation is limited. This study compared pasireotide and octreotide for their association with complications after simultaneous pancreas-kidney transplantation (SPK). This retrospective study included consecutive patients undergoing SPK's from July 2013 to July 2022. Between July 2013 and April 2020, octreotide was administered 0.1mg s.c. once daily and between May 2020 and July 2022 pasireotide was administered 0.9mg twice daily, both until third postoperative day. Complications within 90days postoperatively were collected, and reoperation rate and Comprehensive Complication index (CCI) ≥ 33.7 (morbidity equal to one reoperation) were used as primary outcomes. Of the 213 patients undergoing SPK, 150 patients received octreotide and 63 pasireotide. Baseline characteristics were comparable. Reoperation rate was 25.3% (n = 38) and 17.5% (n = 11) (p = 0.213) and rate of CCI ≥ 33.7 was 40.7% (n = 61) and 30.2% (n = 19) (p = 0.148) in octreotide and pasireotide groups, respectively. When adjusted with donor BMI, pancreas donor risk index, and donor sex, receiving pasireotide translated into OR 0.49 (95% CI: 0.25-0.96 p = 0.037) for CCI ≥ 33.7. Pasireotide was independently associated with lower postoperative morbidity within 90days of SPK compared to octreotide.

Multiview Clustering to Identify Novel Kidney Donor Phenotypes for Assessing Graft Survival in Older Transplant Recipients.

Older transplant recipients are at a relatively increased risk of graft failure following transplantation and some of this risk may relate to donor characteristics. Unsupervised clustering using machine learning may be a novel approach to identify donor phenotypes that may then be used to evaluate outcomes for older recipients. Using a cohort of older recipients, the purpose of this study was to A) use unsupervised clustering to identify donor phenotypes and B) determine the risk of death/graft failure for recipients of each donor phenotype. We analyzed a nationally representative cohort of kidney transplant recipients age >65 years captured using the Scientific Registry of Transplant Recipients between 2000-2017. Unsupervised clustering was used to generate phenotypes using donor characteristics inclusive of variables in the kidney donor risk index (KDRI). Cluster assignment was internally validated. Outcomes included all-cause graft failure (including mortality) and delayed graft function (DGF). Differences in the distribution of KDRI scores were also compared across the clusters. All-cause graft failure was compared for recipients of donor kidneys from each cluster using a multivariable Cox-Survival analysis. Overall, 23,558 donors were separated into five clusters. The area under the curve for internal validation of cluster assignment was 0.89. Recipients of donor kidneys from two clusters were found to be at high risk of all-cause graft failure relative to the lowest risk cluster (adjusted hazards ratio 1.86, 95% CI 1.69-2.05 and 1.73, 95% CI 1.61-1.87). Only, one of these high-risk clusters had high proportions of donors with established risk factors (i.e., hypertension, diabetes). KDRI scores were similar for the highest and lowest risk clusters (1.40 [1.18-1.67] and 1.37 [1.15-1.65], respectively). Unsupervised clustering can identify novel donor phenotypes comprised of established donor characteristics that, in turn, may be associated with different risks of graft loss for older transplant recipients.

The UK kidney donor risk index poorly predicts long-term transplant survival in paediatric kidney transplant recipients.

The UK kidney offering scheme introduced a kidney donor risk index (UK-KDRI) to improve the utility of deceased-donor kidney allocations. The UK-KDRI was derived using adult donor and recipient data. We assessed this in a paediatric cohort from the UK transplant registry. We performed Cox survival analysis on first kidney-only deceased brain-dead transplants in paediatric (<18 years) recipients from 2000-2014. The primary outcome was death-censored allograft survival >30 days post-transplant. The main study variable was UK-KDRI derived from seven donor risk-factors, categorised into four groups (D1-low risk, D2, D3 and D4-highest risk). Follow-up ended on 31-December-2021. 319/908 patients experienced transplant loss with rejection as the main cause (55%). The majority of paediatric patients received donors from D1 donors (64%). There was an increase in D2-4 donors during the study period, whilst the level of HLA mismatching improved. The KDRI was not associated with allograft failure. In multi-variate analysis, increasing recipient age [adjusted HR and 95%CI: 1.05(1.03-1.08) per-year, p<0.001], recipient minority ethnic group [1.28(1.01-1.63), p<0.05), dialysis before transplant [1.38(1.04-1.81), p<0.005], donor height [0.99 (0.98-1.00) per centimetre, p<0.05] and level of HLA mismatch [Level 3: 1.92(1.19-3.11); Level 4: 2.40(1.26-4.58) versus Level 1, p<0.01] were associated with worse outcomes. Patients with Level 1 and 2 HLA mismatches (0 DR +0/1 B mismatch) had median graft survival >17 years regardless of UK-KDRI groups. Increasing donor age was marginally associated with worse allograft survival [1.01 (1.00-1.01) per year, p=0.05]. Adult donor risk scores were not associated with long-term allograft survival in paediatric patients. The level of HLA mismatch had the most profound effect on survival. Risk models based on adult data alone may not have the same validity for paediatric patients and therefore all age-groups should be included in future risk prediction models.

Utilization of the Pancreas From Donors With an Extremely High Pancreas Donor Risk Index: Report of the National Registry of Pancreas Transplantation.

Pancreas transplants from expanded criteria donors are performed widely in Japan because there is a shortage of brain-dead donors. However, the effectiveness of this strategy is unknown. We retrospectively studied 371 pancreas transplants to evaluate the possibility of pancreas transplantation from expanded criteria donors by the Pancreas Donor Risk Index (PDRI). Patients were divided into five groups according to quintiles of PDRI values (Q1-Q5). The 1-year pancreas graft survival rates were 94.5% for Q1, 91.9% for Q2, 90.5% for Q3, 89.3% for Q4, and 79.6% for Q5, and were significantly lower with a lower PDRI (p = 0.04). A multivariate analysis showed that the PDRI, donor hemoglobin A1c values, and pancreas transplantation alone significantly predicted 1-year pancreas graft survival (all p < 0.05). Spline curve analysis showed that the PDRI was incrementally associated with an increased risk of 1-year graft failure. In the group with a PDRI ≥ 2.87, 8/56 patients had graft failures within 1month, and all were due to graft thrombosis. The PDRI is a prognostic factor related to the 1-year graft survival rate. However, pancreas transplantation from high-PDRI donors shows acceptable results and could be an alternative when the donor pool is insufficient.

Liver Transplantation in Rescue Allocation: Comparison of the Donor Risk Index, Balance of Risk Score and Graft Function After Liver Transplantation

Background: In the model for end-stage liver disease (MELD) system, the use of livers from rescue allocation (RA), those refused for the first five of the ranking, have conflicting results in the literature. Objective: Analysis of the characteristics of the different simulated patterns of allocation (pattern vs. rescue), using the donor risk index (DRI), the balance of risk score (BAR) and its impact on the graft function. Method: Cohort of 233 liver transplants in adults, performed between 2015 and 2022. Results: General characteristics, age 50.3 ± 11.8 years; 64.81% CHILD C; MELD in allocation 22.4 ± 7.6. Initial graft dysfunction in 12.45% and primary nonfunction (PNF) in 8.15%; with DRI 1.41 ± 0.32. Transplants in RA occurred in 18.03% (n = 42) of cases, in patients with significantly lower MELD (18.4 ± 4.8) and BAR (7.1 ± 3.2) compared to standard allocation (23.2 ± 7.9; 9.2 ± 4.2 respectively). The DRI was significantly higher (p = 0.001) in the RA (1.58 ± 0.37). Age (p = 0.23) and body mass index (p = 0.85) of the donor, cold ischemia time (CIT) (p = 0.10) showed no differences between the groups. RA organs came more often from out-of-state (50% vs. 2.62%) and less harvested by our surgical team (38.1% vs. 79.0%). Early graft dysfunction (EGD) in 16.67% (n = 7); 14.29% (n = 6) of primary nonfunctioning in the RA group, percentage higher than in the standard allocation group with 11.52% (n = 22) and 6.81% (n = 13) respectively; however, there was no difference with statistical significance (p = 0.052). There was no difference in survival (73.81% vs. 72.25%; p = 0.83). Conclusion: A strategy more frequently employed in patients with less severe conditions according to BAR score, liver grafts in a RA rescue allocation system had higher DRI scores and did not provide a difference in short-term survival.

Variation of Liver Transplant Practice and Outcomes During Public Holidays in the United States: Analysis of United Network for Organ Sharing Registry.

We analyzed the United Network for Organ Sharing registry data for 55 200 adult patients who underwent an LT between 2010 and 2019. Patients were grouped according to LT receipt during public holidays ±3 d (n = 7350) and nonholiday periods (n = 47 850). The overall post-LT mortality hazard was analyzed using multivariable Cox regression models. LT recipient characteristics were similar between public holidays and nonholidays. Compared with nonholidays, deceased donors during public holidays had a lower donor risk index (median [interquartile range]: holidays 1.52 [1.29-1.83] versus nonholidays 1.54 [1.31-1.85]; P = 0.001) and shorter cold ischemia time (median [interquartile range]: holidays 5.82 h [4.52-7.22] versus nonholidays 5.91 h [4.62-7.38]; P < 0.001). Propensity score matching 4-to-1 was done to adjust for donor and recipient confounders (n = 33 505); LT receipt during public holidays (n = 6701) was associated with a lower risk of overall mortality (hazard ratio 0.94 [95% confidence interval, 0.86-0.99]; P = 0.046). The number of livers that were not recovered for transplant was higher during public holidays compared with nonholidays (15.4% versus 14.5%, respectively; P = 0.03). Although LT performed during public holidays was associated with improved overall patient survival, liver discard rates were higher during public holidays compared with nonholidays.

Normothermic machine perfusion for older transplant recipients.

Elderly patients (≥65 years old) are increasingly undergoing liver transplantation and are more likely to be removed from the waitlist. Normothermic machine perfusion (NMP) holds promise in expanding the number of livers available for transplant and improving outcomes for marginal donors and recipients. We aimed to determine the impact of NMP on outcomes in elderly recipients at our institution and nationally using the UNOS database. The use of NMP on outcomes in elderly recipients was reviewed using both the UNOS/SRTR database (2016-2022) and institutional data (2018-2020). Characteristics and clinical outcomes were compared between the NMP and static cold (control) groups within both populations. Nationally, using the UNOS/SRTR database, we identified 165 elderly recipients from 28 centers who received a liver allograft undergoing NMP and 4270 that underwent traditional cold static storage. NMP donors were older (48.3 vs. 43.4 years, p< 0.01), had similar rates of steatosis (8.5% vs 8.5%, p= 0.58), were more likely to be from a DCD (41.8% vs 12.3%, p< 0.01), and had a higher donor risk index (DRI; 1.70 vs. 1.60, p< 0.02). NMP recipients had similar age but had a lower MELD score at transplant (17.9 vs. 20.7, p= 0.01). Despite increased marginality of the donor graft, NMP recipients had similar allograft survival and decreased length of stay, even after accounting for recipient characteristics including MELD. Institutional data showed that 10 elderly recipients underwent NMP and 68 underwent cold static storage. At our institution, NMP recipients had a similar length of stay, rates of complications, and readmissions. NMP may mitigate donor risk factors that are relative contraindications for transplantation in elderly liver recipients, increasing the donor pool. The application of NMP in older recipients should be considered.