AI-driven translations for kidney transplant equity in Hispanic populations

Health equity and accessing Spanish kidney transplant information continues being a substantial challenge facing the Hispanic community. This study evaluated ChatGPT's capabilities in translating 54 English kidney transplant frequently asked questions (FAQs) into Spanish using two versions of the AI model, GPT-3.5 and GPT-4.0. The FAQs included 19 from Organ Procurement and Transplantation Network (OPTN), 15 from National Health Service (NHS), and 20 from National Kidney Foundation (NKF). Two native Spanish-speaking nephrologists, both of whom are of Mexican heritage, scored the translations for linguistic accuracy and cultural sensitivity tailored to Hispanics using a 1-5 rubric. The inter-rater reliability of the evaluators, measured by Cohen's Kappa, was 0.85. Overall linguistic accuracy was 4.89 ± 0.31 for GPT-3.5 versus 4.94 ± 0.23 for GPT-4.0 (non-significant p = 0.23). Both versions scored 4.96 ± 0.19 in cultural sensitivity (p = 1.00). By source, GPT-3.5 linguistic accuracy was 4.84 ± 0.37 (OPTN), 4.93 ± 0.26 (NHS), 4.90 ± 0.31 (NKF). GPT-4.0 scored 4.95 ± 0.23 (OPTN), 4.93 ± 0.26 (NHS), 4.95 ± 0.22 (NKF). For cultural sensitivity, GPT-3.5 scored 4.95 ± 0.23 (OPTN), 4.93 ± 0.26 (NHS), 5.00 ± 0.00 (NKF), while GPT-4.0 scored 5.00 ± 0.00 (OPTN), 5.00 ± 0.00 (NHS), 4.90 ± 0.31 (NKF). These high linguistic and cultural sensitivity scores demonstrate Chat GPT effectively translated the English FAQs into Spanish across systems. The findings suggest Chat GPT's potential to promote health equity by improving Spanish access to essential kidney transplant information. Additional research should evaluate its medical translation capabilities across diverse contexts/languages. These English-to-Spanish translations may increase access to vital transplant information for underserved Spanish-speaking Hispanic patients.

Empowering inclusivity: improving readability of living kidney donation information with ChatGPT

Background

Addressing disparities in living kidney donation requires making information accessible across literacy levels, especially important given that the average American adult reads at an 8th-grade level. This study evaluated the effectiveness of ChatGPT, an advanced AI language model, in simplifying living kidney donation information to an 8th-grade reading level or below.

Methods

We used ChatGPT versions 3.5 and 4.0 to modify 27 questions and answers from Donate Life America, a key resource on living kidney donation. We measured the readability of both original and modified texts using the Flesch-Kincaid formula. A paired t-test was conducted to assess changes in readability levels, and a statistical comparison between the two ChatGPT versions was performed.

Results

Originally, the FAQs had an average reading level of 9.6 ± 1.9. Post-modification, ChatGPT 3.5 achieved an average readability level of 7.72 ± 1.85, while ChatGPT 4.0 reached 4.30 ± 1.71, both with a p-value <0.001 indicating significant reduction. ChatGPT 3.5 made 59.26% of answers readable below 8th-grade level, whereas ChatGPT 4.0 did so for 96.30% of the texts. The grade level range for modified answers was 3.4-11.3 for ChatGPT 3.5 and 1-8.1 for ChatGPT 4.0.

Conclusion

Both ChatGPT 3.5 and 4.0 effectively lowered the readability grade levels of complex medical information, with ChatGPT 4.0 being more effective. This suggests ChatGPT's potential role in promoting diversity and equity in living kidney donation, indicating scope for further refinement in making medical information more accessible.

Electrocardiography-based Artificial Intelligence Algorithms Aid in Prediction of Long-term Mortality After Kidney Transplantation

BACKGROUND

Predicting long-term mortality postkidney transplantation (KT) using baseline clinical data presents significant challenges. This study aims to evaluate the predictive power of artificial intelligence (AI)-enabled analysis of preoperative electrocardiograms (ECGs) in forecasting long-term mortality following KT.

METHODS

We analyzed preoperative ECGs from KT recipients at three Mayo Clinic sites (Minnesota, Florida, and Arizona) between January 1, 2006, and July 30, 2021. The study involved 6 validated AI algorithms, each trained to predict future development of atrial fibrillation, aortic stenosis, low ejection fraction, hypertrophic cardiomyopathy, amyloid heart disease, and biological age. These algorithms' outputs based on a single preoperative ECG were correlated with patient mortality data.

RESULTS

Among 6504 KT recipients included in the study, 1764 (27.1%) died within a median follow-up of 5.7 y (interquartile range: 3.00-9.29 y). All AI-ECG algorithms were independently associated with long-term all-cause mortality (P < 0.001). Notably, few patients had a clinical cardiac diagnosis at the time of transplant, indicating that AI-ECG scores were predictive even in asymptomatic patients. When adjusted for multiple clinical factors such as recipient age, diabetes, and pretransplant dialysis, AI algorithms for atrial fibrillation and aortic stenosis remained independently associated with long-term mortality. These algorithms also improved the C-statistic for predicting overall (C = 0.74) and cardiac-related deaths (C = 0.751).

CONCLUSIONS

The findings suggest that AI-enabled preoperative ECG analysis can be a valuable tool in predicting long-term mortality following KT and could aid in identifying patients who may benefit from enhanced cardiac monitoring because of increased risk.

Evaluating Global and Temporal Trends in Pancreas and Islet Cell Transplantation: Public Awareness and Engagement

BACKGROUND

Pancreas transplantation is a crucial surgical intervention for managing diabetes, but it faces challenges such as its invasive nature, stringent patient selection criteria, organ scarcity, and centralized expertise. Despite the steadily increasing number of pancreas transplants in the United States, there is a need to understand global trends in interest to increase awareness of and participation in pancreas and islet cell transplantation.

METHODS

We analyzed Google Search trends for "Pancreas Transplantation" and "Islet Cell Transplantation" from 2004 to 14 November 2023, assessing variations in search interest over time and across geographical locations. The Augmented Dickey-Fuller (ADF) test was used to determine the stationarity of the trends (p < 0.05).

RESULTS

Search interest for "Pancreas Transplantation" varied from its 2004 baseline, with a general decline in peak interest over time. The lowest interest was in December 2010, with a slight increase by November 2023. Ecuador, Kuwait, and Saudi Arabia showed the highest search interest. "Islet Cell Transplantation" had its lowest interest in December 2016 and a more pronounced decline over time, with Poland, China, and South Korea having the highest search volumes. In the U.S., "Pancreas Transplantation" ranked 4th in interest, while "Islet Cell Transplantation" ranked 11th. The ADF test confirmed the stationarity of the search trends for both procedures.

CONCLUSIONS

"Pancreas Transplantation" and "Islet Cell Transplantation" showed initial peaks in search interest followed by a general downtrend. The stationary search trends suggest a lack of significant fluctuations or cyclical variations. These findings highlight the need for enhanced educational initiatives to increase the understanding and awareness of these critical transplant procedures among the public and professionals.

Duration of Dialysis in Acute Kidney Injury Donors and Transplant Outcomes

BACKGROUND

Acute kidney injury (AKI) kidneys, including those from donors on dialysis, are often underutilized, although there is increasing data available demonstrating good transplant outcomes. To date, data on the duration of donor dialysis and transplant outcomes are limited.

STUDY DESIGN

This was a single-center study of deceased donor kidney transplants from 2010 to 2022. The study cohort consisted of recipients of deceased donor kidney transplants from donors with AKI and on dialysis. Three groups were identified based on the predetermined interquartile range of donor dialysis duration: 1 to 2 dialysis days, 3 to 4 dialysis days, and 5 or more dialysis days.

RESULTS

During this period, 765 AKI deceased donor transplants were performed, of which 230 were from donors on dialysis. The median dialysis duration was 2 days with a maximum of 13 days. Across the 3 groups, there were no differences in recipient age (p = 0.23) or dialysis vintage (p = 0.70). Donor age (p = 0.86) and kidney donor profile index (p = 0.57) were comparable between the groups. Recipients of deceased donor kidney transplants from donors on dialysis 5 or more days had lower terminal creatinine levels (p = 0.003) and longer cold ischemia times (p = 0.04). Posttransplant, the median length of hospital stay was 3 days for all groups (p = 0.75). There were no differences in delayed graft function occurrence (94.4% vs 86.8% vs 92.1%, p = 0.19), duration of delayed graft function (p = 0.56), or readmissions (p = 0.99). At 1 year posttransplant, the estimated glomerular filtration rate (p = 0.76), patient survival (p = 0.82), or death-censored graft survival (p = 0.28) were comparable.

CONCLUSIONS

Excellent outcomes have been observed in AKI deceased donor kidney transplants, including those coming from donors on dialysis. In this small cohort, the duration of donor dialysis did not adversely affect outcomes. Cautious expansion of the donor pool, including donors on dialysis, should be considered given the ongoing organ shortage.

Re-assessing prolonged cold ischemia time in kidney transplantation through machine learning consensus clustering

BACKGROUND

We aimed to cluster deceased donor kidney transplant recipients with prolonged cold ischemia time (CIT) using an unsupervised machine learning approach.

METHODS

We performed consensus cluster analysis on 11 615 deceased donor kidney transplant patients with CIT exceeding 24 h using OPTN/UNOS data from 2015 to 2019. Cluster characteristics of clinical significance were identified, and post-transplant outcomes were compared.

RESULTS

Consensus cluster analysis identified two clinically distinct clusters. Cluster 1 was characterized by young, non-diabetic patients who received kidney transplants from young, non-hypertensive, non-ECD deceased donors with lower KDPI scores. In contrast, the patients in cluster 2 were older and more likely to have diabetes. Cluster 2 recipients were more likely to receive transplants from older donors with a higher KDPI. There was lower use of machine perfusion in Cluster 1 and incrementally longer CIT in Cluster 2. Cluster 2 had a higher incidence of delayed graft function (42% vs. 29%), and lower 1-year patient (95% vs. 98%) and death-censored (95% vs. 97%) graft survival compared to Cluster 1.

CONCLUSIONS

Unsupervised machine learning characterized deceased donor kidney transplant recipients with prolonged CIT into two clusters with differing outcomes. Although Cluster 1 had more favorable recipient and donor characteristics and better survival, the outcomes observed in Cluster 2 were also satisfactory. Overall, both clusters demonstrated good survival suggesting opportunities for transplant centers to incrementally increase CIT.

Utilizing kidneys from a donor with bile-cast nephropathy

Here we discuss the successful utilization of a pair of deceased donor kidneys with bile-cast nephropathy. The donor had a kidney donor profile index of 48% and an acute kidney injury requiring continuous renal replacement therapy. Peak donor bilirubin was 40.5 mg/dL, and renal wedge biopsies showed bile-cast nephropathy. Both recipients had delayed graft function lasting up to 4 weeks. The 4-month biopsies showed mild interstitial fibrosis, tubular atrophy, and a resolution of bile casts. These kidney allografts showed the reversible course of cholemic nephropathy and the potential for increasing the utilization of previously discarded kidneys.

Liver transplant outcomes using late allocation grafts

Post-cross clamp late allocation (LA) liver allografts are at increased risk for discard for many reasons including logistical complexity. Nearest neighbor propensity score matching was used to match 2 standard allocation (SA) offers to every 1 LA liver offer performed at our center between 2015 and 2021. Propensity scores were based on a logistic regression model including recipient age, recipient sex, graft type (donation after circulatory death vs. donation after brain death), Model for End-stage Liver Disease (MELD), and DRI score. During this time, 101 liver transplants (LT) were performed at our center using LA offers. In comparing LA and SA offers, there were no differences in recipient characteristics including indication for transplant ( p = 0.29), presence of PVT ( p = 0.19), TIPS ( p = 0.83), and HCC status ( p = 0.24). LA grafts came from younger donors (mean age 43.6 vs. 48.9 y, p = 0.009) and were more likely to come from regional or national Organ Procurement Organizations (OPOs) ( p < 0.001). Cold ischemia time was longer for LA grafts (median 8.5 vs 6.3 h, p < 0.001). Following LT, there were no differences between the 2 groups in intensive care unit ( p = 0.22) and hospital ( p = 0.49) lengths of stay, need for endoscopic interventions ( p = 0.55), or biliary strictures ( p = 0.21). Patient (HR 1.0, 95% CI, 0.47-2.15, p = 0.99) and graft (HR 1.23, 95% CI, 0.43-3.50, p = 0.70) survival did not vary between the LA and SA cohorts. One-year LA and SA patient survival was 95.1% and 95.0%; 1-year graft survival was 93.1% and 92.1%, respectively. Despite the additional logistical complexity and longer cold ischemia time, LT outcomes utilizing LA grafts are similar to those allocated by means of SA. Improving allocation policies specific to LA offers, as well as the sharing of best practices between transplant centers and OPOs, are opportunities to further help minimize unnecessary discards.

Outcomes with transplanting kidneys offered through expedited allocation

INTRODUCTION

Expedited out-of-sequence deceased donor kidney allocation is a strategy to avoid discards after early placement attempts have been unsuccessful. Our study aimed to assess outcomes and characteristics of these transplanted kidneys.

METHODS

KDPI matching was performed between expedited allocation (EA) and standard allocation (SA) deceased donor kidney transplants performed at our center.

RESULTS

Between 2018 and 2021, there were 225 EA offers, and 189 (84%) were transplanted. EA recipients were older (p = .007) and had shorter dialysis vintage (p < .0001). EA kidneys were likely to be nationally allocated (p < .001), have AKI (p < .0001) and longer CIT (p < .0001). There were no differences in EA and SA time-zero kidney biopsies (ci, p = .07; ct, p = .89; cv, p = .95; ah, p = .79). EA kidneys had more DGF (p = .0006), but there were no differences in DGF duration (p = .83), hospital length of stay (p = .43), 1- and 2-year eGFR (p = .16, p = .99), patient (p = .34), or death-censored graft (p = .66) survival.

CONCLUSION

During this study period, our center transplanted 189 kidneys through EA following local-regional declines. These kidneys often came from AKI donors and had more DGF but had similar outcomes to KDPI-matched SA kidneys. Although it has been suggested that EA has the potential to worsen transplant disparities, transplant center level decisions on organ acceptance contribute to these variations.

Favorable outcomes in Hispanic recipients receiving simultaneous pancreas kidney transplantation

The objective of this study was to compare the long-term outcomes of Hispanic versus white recipients who underwent simultaneous pancreas kidney transplantation (SPKT). This single-center study, conducted from 2003 to 2022, had a median follow-up of 7.5 years. The study included 91 Hispanic and 202 white SPKT recipients. The mean age (44 vs. 46 years), percentage of males (67% vs. 58%), and body mass index (BMI) (25.6 vs. 25.3 kg/m2 ) were similar between the Hispanic and white groups. The Hispanic group had more recipients with type 2 diabetes (38%) compared to the white group (5%, p < .001). The duration of dialysis was longer in Hispanics (640 vs. 473 days, p = .02), and fewer patients received preemptive transplants (10% vs. 29%, p < .01) compared to whites. Hospital length of stay, rates of BK Viremia, and acute rejection episodes within 1 year were similar between the groups. The estimated 5-year kidney, pancreas, and patient survival rates were also similar between the groups, 94%, 81%, and 95% in Hispanics, compared to 90%, 79%, and 90% in whites. Increasing age and longer duration of dialysis were risk factors for death. Although Hispanic recipients had a longer duration on dialysis and fewer preemptive transplants, the survival rates were similar to those of white recipients. However, referring providers and many transplant centers continue to overlook pancreas transplants for appropriately selected patients with type 2 diabetes, particularly among minority populations. As a transplant community, it is crucial that we make efforts to comprehend and tackle these obstacles to transplantation.

Enhancing Kidney Transplant Care through the Integration of Chatbot

Kidney transplantation is a critical treatment option for end-stage kidney disease patients, offering improved quality of life and increased survival rates. However, the complexities of kidney transplant care necessitate continuous advancements in decision making, patient communication, and operational efficiency. This article explores the potential integration of a sophisticated chatbot, an AI-powered conversational agent, to enhance kidney transplant practice and potentially improve patient outcomes. Chatbots and generative AI have shown promising applications in various domains, including healthcare, by simulating human-like interactions and generating contextually appropriate responses. Noteworthy AI models like ChatGPT by OpenAI, BingChat by Microsoft, and Bard AI by Google exhibit significant potential in supporting evidence-based research and healthcare decision making. The integration of chatbots in kidney transplant care may offer transformative possibilities. As a clinical decision support tool, it could provide healthcare professionals with real-time access to medical literature and guidelines, potentially enabling informed decision making and improved knowledge dissemination. Additionally, the chatbot has the potential to facilitate patient education by offering personalized and understandable information, addressing queries, and providing guidance on post-transplant care. Furthermore, under clinician or transplant pharmacist supervision, it has the potential to support post-transplant care and medication management by analyzing patient data, which may lead to tailored recommendations on dosages, monitoring schedules, and potential drug interactions. However, to fully ascertain its effectiveness and safety in these roles, further studies and validation are required. Its integration with existing clinical decision support systems may enhance risk stratification and treatment planning, contributing to more informed and efficient decision making in kidney transplant care. Given the importance of ethical considerations and bias mitigation in AI integration, future studies may evaluate long-term patient outcomes, cost-effectiveness, user experience, and the generalizability of chatbot recommendations. By addressing these factors and potentially leveraging AI capabilities, the integration of chatbots in kidney transplant care holds promise for potentially improving patient outcomes, enhancing decision making, and fostering the equitable and responsible use of AI in healthcare.

Characteristics of Kidney Transplant Recipients with Prolonged Pre-Transplant Dialysis Duration as Identified by Machine Learning Consensus Clustering: Pathway to Personalized Care

Longer pre-transplant dialysis duration is known to be associated with worse post-transplant outcomes. Our study aimed to cluster kidney transplant recipients with prolonged dialysis duration before transplant using an unsupervised machine learning approach to better assess heterogeneity within this cohort. We performed consensus cluster analysis based on recipient-, donor-, and transplant-related characteristics in 5092 kidney transplant recipients who had been on dialysis ≥ 10 years prior to transplant in the OPTN/UNOS database from 2010 to 2019. We characterized each assigned cluster and compared the posttransplant outcomes. Overall, the majority of patients with ≥10 years of dialysis duration were black (52%) or Hispanic (25%), with only a small number (17.6%) being moderately sensitized. Within this cohort, three clinically distinct clusters were identified. Cluster 1 patients were younger, non-diabetic and non-sensitized, had a lower body mass index (BMI) and received a kidney transplant from younger donors. Cluster 2 recipients were older, unsensitized and had a higher BMI; they received kidney transplant from older donors. Cluster 3 recipients were more likely to be female with a higher PRA. Compared to cluster 1, cluster 2 had lower 5-year death-censored graft (HR 1.40; 95% CI 1.16-1.71) and patient survival (HR 2.98; 95% CI 2.43-3.68). Clusters 1 and 3 had comparable death-censored graft and patient survival. Unsupervised machine learning was used to characterize kidney transplant recipients with prolonged pre-transplant dialysis into three clinically distinct clusters with variable but good post-transplant outcomes. Despite a dialysis duration ≥ 10 years, excellent outcomes were observed in most recipients, including those with moderate sensitization. A disproportionate number of minority recipients were observed within this cohort, suggesting multifactorial delays in accessing kidney transplantation.

Past, Current, and Future Perspectives on Transplanting Acute Kidney Injury Kidneys

(1) Background: Acute kidney injury (AKI) kidneys have high non-utilization rates due to concerns regarding unfavorable outcomes. In this paper, we aimed to review the past, present, and future opinions on AKI kidneys. (2) Methods: A PubMed search was conducted for topics relevant to AKI kidney transplantation. (3) Results: Current short- and long-term data on AKI kidneys have demonstrated good outcomes including favorable graft function and survival. The role of procurement biopsies is controversial, but they have been shown to be beneficial in AKI kidneys by allowing clinicians to differentiate between reversible tubular injury and irreversible cortical necrosis. Machine perfusion has also been applied to AKI kidneys and has been shown to reduce delayed graft function (DGF). The incidence of DGF increases with AKI severity and its management can be challenging. Strategies employed to counteract this have included early initiation of dialysis after kidney transplantation, early targeting of adequate immunosuppression levels to minimize rejection risk, and establishment of outpatient dialysis. (4) Conclusions: Despite good outcomes, there continue to be barriers that impact AKI kidney utilization. Successful strategies have included use of procurement biopsies or machine perfusion and expectant management of DGF. With increasing experience, better use of AKI kidneys can result in additional opportunities to expand the donor pool.

Expanding Liver Transplant Opportunities in Older Patients With Nonconventional Grafts

INTRODUCTION

Broader use of donation after circulatory death (DCD) and nonconventional grafts for liver transplant helps reduce disparities in organ availability. Limited data, however, exists on outcomes specific to nonconventional graft utilization in older patients. As such, this study aimed to investigate outcomes specific to conventional and nonconventional graft utilization in recipients > 70 y of age.

METHODS

1-to-3 matching based on recipient sex, Model for End-Stage Liver Disease score, and donor type was performed on patients ≥70 and <70 y of age who underwent liver transplant alone at Mayo Clinic Arizona between 2015 and 2020. Primary outcomes were posttransplant patient and liver allograft survival for recipients greater than or less than 70 y of age. Secondary outcomes included grafts utilization patterns, hospital length of stay, need for reoperation, biliary complications and disposition at time of hospital discharge.

RESULTS

In this cohort, 36.1% of grafts came from DCD donors, 17.4% were postcross clamp offers, and 20.8% were nationally allocated. Median recipient ages were 59 and 71 y (P < 0.01). Recipients had similar Intensive care unit (P = 0.82) and hospital (P = 0.14) lengths of stay, and there were no differences in patient (P = 0.68) or graft (P = 0.38) survival. When comparing donation after brain death and DCD grafts in those >70 y, there were no differences in patient (P = 0.89) or graft (P = 0.71) survival.

CONCLUSIONS

Excellent outcomes can be achieved in older recipients, even with use of nonconventional grafts. Expanded use of nonconventional grafts can help facilitate transplant opportunities in older patients.

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.

Differences between Very Highly Sensitized Kidney Transplant Recipients as Identified by Machine Learning Consensus Clustering

Background and Objectives: The aim of our study was to categorize very highly sensitized kidney transplant recipients with pre-transplant panel reactive antibody (PRA) ≥ 98% using an unsupervised machine learning approach as clinical outcomes for this population are inferior, despite receiving increased allocation priority. Identifying subgroups with higher risks for inferior outcomes is essential to guide individualized management strategies for these vulnerable recipients. Materials and Methods: To achieve this, we analyzed the Organ Procurement and Transplantation Network (OPTN)/United Network for Organ Sharing (UNOS) database from 2010 to 2019 and performed consensus cluster analysis based on the recipient-, donor-, and transplant-related characteristics in 7458 kidney transplant patients with pre-transplant PRA ≥ 98%. The key characteristics of each cluster were identified by calculating the standardized mean difference. The post-transplant outcomes were compared between the assigned clusters. Results: We identified two distinct clusters and compared the post-transplant outcomes among the assigned clusters of very highly sensitized kidney transplant patients. Cluster 1 patients were younger (median age 45 years), male predominant, and more likely to have previously undergone a kidney transplant, but had less diabetic kidney disease. Cluster 2 recipients were older (median 54 years), female predominant, and more likely to be undergoing a first-time transplant. While patient survival was comparable between the two clusters, cluster 1 had lower death-censored graft survival and higher acute rejection compared to cluster 2. Conclusions: The unsupervised machine learning approach categorized very highly sensitized kidney transplant patients into two clinically distinct clusters with differing post-transplant outcomes. A better understanding of these clinically distinct subgroups may assist the transplant community in developing individualized care strategies and improving the outcomes for very highly sensitized kidney transplant patients.

Reassessing Geographic, Logistical, and Cold Ischemia Cutoffs in Liver Transplantation

INTRODUCTION

Liver acceptance patterns vary significantly between transplant centers. Data pertaining to outcomes of livers declined by local and regional centers and allocated nationally remains limited.

PROJECT AIM

The objective was to compare post-liver transplant outcomes between liver allografts transplanted as a result of national and local-regional allocation.

DESIGN

This was a retrospective evaluation of 109 nationally allocated liver allografts used for transplant by a single center. Outcomes of nationally allocated grafts were compared to standard allocation grafts (N  =  505) during the same period.

RESULTS

Recipients of nationally allocated grafts had lower model for end stage liver disease scores (17 vs 22, P  =  .001). Nationally allocated grafts were more likely to be post-cross clamp offers (29.4% vs 13.4%, P  =  .001) and have longer cold ischemia times (median hours 7.8 vs 5.5, P  =  .001). Early allograft dysfunction was common (54.1% vs 52.5%, P  =  .75) and did not impact hospital length of stay (median 5 vs 6 days, P  =  .89). There were no differences in biliary complications (P  =  .11). There were no differences in patient (P  =  .88) or graft survival (P  =  .35). In a multivariate model, after accounting for differences in cold ischemia time and posttransplant biliary complications, nationally allocated grafts were not associated with increased risk for graft loss (HR 0.9, 95% CI 0.4-1.8). Abnormal liver biopsy findings (33.0%) followed by donor donation after circulatory death status (22.9%) were the most common reasons for decline by local-regional centers.

CONCLUSION

Despite longer cold ischemia times, patient and graft survival outcomes remain excellent and comparable to those seen from standard allocation grafts.

Distinct Phenotypes of Non-Citizen Kidney Transplant Recipients in the United States by Machine Learning Consensus Clustering

BACKGROUND

Better understanding of the different phenotypes/subgroups of non-U.S. citizen kidney transplant recipients may help the transplant community to identify strategies that improve outcomes among non-U.S. citizen kidney transplant recipients. This study aimed to cluster non-U.S. citizen kidney transplant recipients using an unsupervised machine learning approach; Methods: We conducted a consensus cluster analysis based on recipient-, donor-, and transplant- related characteristics in non-U.S. citizen kidney transplant recipients in the United States from 2010 to 2019 in the OPTN/UNOS database using recipient, donor, and transplant-related characteristics. Each cluster's key characteristics were identified using the standardized mean difference. Post-transplant outcomes were compared among the clusters; Results: Consensus cluster analysis was performed in 11,300 non-U.S. citizen kidney transplant recipients and identified two distinct clusters best representing clinical characteristics. Cluster 1 patients were notable for young age, preemptive kidney transplant or dialysis duration of less than 1 year, working income, private insurance, non-hypertensive donors, and Hispanic living donors with a low number of HLA mismatch. In contrast, cluster 2 patients were characterized by non-ECD deceased donors with KDPI <85%. Consequently, cluster 1 patients had reduced cold ischemia time, lower proportion of machine-perfused kidneys, and lower incidence of delayed graft function after kidney transplant. Cluster 2 had higher 5-year death-censored graft failure (5.2% vs. 9.8%; p < 0.001), patient death (3.4% vs. 11.4%; p < 0.001), but similar one-year acute rejection (4.7% vs. 4.9%; p = 0.63), compared to cluster 1; Conclusions: Machine learning clustering approach successfully identified two clusters among non-U.S. citizen kidney transplant recipients with distinct phenotypes that were associated with different outcomes, including allograft loss and patient survival. These findings underscore the need for individualized care for non-U.S. citizen kidney transplant recipients.

Declining Medicare reimbursement in abdominal transplantation from 2000 to 2021

BACKGROUND

The Centers for Medicare and Medicaid Services is a major payer for abdominal transplant services. Reimbursement reductions could have a major impact on the transplant surgical workforce and hospitals. Yet government reimbursement trends in abdominal transplantation have not been fully characterized.

METHODS

We performed an economic analysis to characterize changes in inflation-adjusted trends in Medicare surgical reimbursement for abdominal transplant procedures. Using the Medicare Fee Schedule Look-Up Tool, we performed a procedure code-based surgical reimbursement rate analysis. Reimbursement rates were adjusted for inflation to calculate overall changes in reimbursement, overall year-over-year, 5-year year-over-year, and compound annual growth rate from 2000 to 2021.

RESULTS

We observed declines in adjusted reimbursement of common abdominal transplant procedures, including liver (-32.4%), kidney with and without nephrectomy (-24.2% and -24.1%, respectively), and pancreas transplant (-15.2%) (all, P < .05). Overall, the yearly average change for liver, kidney with and without nephrectomy, and pancreas transplant were -1.54%, -1.15%, -1.15%, and -0.72%. Five-year annual change averaged -2.69%, -2.35%, -2.64%, and -2.43%, respectively. The overall average compound annual growth rate was -1.27%.

CONCLUSION

This analysis depicts a worrisome reimbursement pattern for abdominal transplant procedures. Transplant surgeons, centers, and professional organizations should note these trends to advocate sustainable reimbursement policy and to preserve continued access to transplant services.

Current opinions on DGF management practices: A survey of the United States and Canada

INTRODUCTION

Significant center-to-center variation in attitudes and management of delayed graft function (DGF) remains common.

METHODS

A survey to describe current DGF practices was developed by workgroup members sponsored by the National Kidney Foundation (NKF) and was distributed to both the NKF DGF workgroup members, kidney transplant program directors and the transplant community within the United States and Canada. Seventy-one percent of NKF workgroup members completed the survey along with 70 unique the United States and three Canadian kidney transplant programs. All Organ Procurement and Transplantation Network (OPTN) regions were represented.

RESULTS

DGF was reported to occur at rate of 20%-40% for most centers with 3.9% indicating their incidence to be >60%. Most centers reported longer hospital lengths of stay and more frequent outpatient visits. Despite the commonality of DGF, only half of centers reported having an established protocol to manage DGF. Kidney allograft biopsies were the only consistent DGF management strategy observed, although use of machine perfusion was also heavily favored. Other DGF management strategies voiced by a minority included having established outpatient practices to care for DGF patients and administering outpatient community-based hemodialysis.

CONCLUSION

Although approximately a third of survey responders indicated that risk of DGF played a role in their willingness to accept organs, most did not feel that increased cost or clinical impact on outcomes was a deterrent. Future strategies, including broader sharing of best practices, redefining terminology specific to DGF, the establishment of DGF dialysis guidelines and improving access to machine perfusion across OPOs may help reduce discard and improve utilization of kidneys at risk for DGF.

Distinct phenotypes of kidney transplant recipients aged 80 years or older in the USA by machine learning consensus clustering

Objectives

This study aimed to identify distinct clusters of very elderly kidney transplant recipients aged ≥80 and assess clinical outcomes among these unique clusters.

Design

Cohort study with machine learning (ML) consensus clustering approach.

Setting and participants

All very elderly (age ≥80 at time of transplant) kidney transplant recipients in the Organ Procurement and Transplantation Network/United Network for Organ Sharing database database from 2010 to 2019.

Main outcome measures

Distinct clusters of very elderly kidney transplant recipients and their post-transplant outcomes including death-censored graft failure, overall mortality and acute allograft rejection among the assigned clusters.

Results

Consensus cluster analysis was performed in 419 very elderly kidney transplant and identified three distinct clusters that best represented the clinical characteristics of very elderly kidney transplant recipients. Recipients in cluster 1 received standard Kidney Donor Profile Index (KDPI) non-extended criteria donor (ECD) kidneys from deceased donors. Recipients in cluster 2 received kidneys from older, hypertensive ECD deceased donors with a KDPI score ≥85%. Kidneys for cluster 2 patients had longer cold ischaemia time and the highest use of machine perfusion. Recipients in clusters 1 and 2 were more likely to be on dialysis at the time of transplant (88.3%, 89.4%). Recipients in cluster 3 were more likely to be preemptive (39%) or had a dialysis duration less than 1 year (24%). These recipients received living donor kidney transplants. Cluster 3 had the most favourable post-transplant outcomes. Compared with cluster 3, cluster 1 had comparable survival but higher death-censored graft failure, while cluster 2 had lower patient survival, higher death-censored graft failure and more acute rejection.

Conclusions

Our study used an unsupervised ML approach to cluster very elderly kidney transplant recipients into three clinically unique clusters with distinct post-transplant outcomes. These findings from an ML clustering approach provide additional understanding towards individualised medicine and opportunities to improve care for very elderly kidney transplant recipients.

Differences between kidney retransplant recipients as identified by machine learning consensus clustering

BACKGROUND

Our study aimed to characterize kidney retransplant recipients using an unsupervised machine-learning approach.

METHODS

We performed consensus cluster analysis based on the recipient-, donor-, and transplant-related characteristics in 17 443 kidney retransplant recipients in the OPTN/UNOS database from 2010 to 2019. We identified each cluster's key characteristics using the standardized mean difference of >.3. We compared the posttransplant outcomes, including death-censored graft failure and patient death among the assigned clusters RESULTS: Consensus cluster analysis identified three distinct clusters of kidney retransplant recipients. Cluster 1 recipients were predominantly white and were less sensitized. They were most likely to receive a living donor kidney transplant and more likely to be preemptive (30%) or need ≤1 year of dialysis (32%). In contrast, cluster 2 recipients were the most sensitized (median PRA 95%). They were more likely to have been on dialysis >1 year, and receive a nationally allocated, low HLA mismatch, standard KDPI deceased donor kidney. Recipients in cluster 3 were more likely to be minorities (37% Black; 15% Hispanic). They were moderately sensitized with a median PRA of 87% and were also most likely to have been on dialysis >1 year. They received locally allocated high HLA mismatch kidneys from standard KDPI deceased donors. Thymoglobulin was the most commonly used induction agent for all three clusters. Cluster 1 had the most favorable patient and graft survival, while cluster 3 had the worst patient and graft survival.

CONCLUSION

The use of an unsupervised machine learning approach characterized kidney retransplant recipients into three clinically distinct clusters with differing posttransplant outcomes. Recipients with moderate allosensitization, such as those represented in cluster 3, are perhaps more disadvantaged in the kidney retransplantation process. Potential opportunities for improvement specific to these re-transplant recipients include working to improve opportunities to improve access to living donor kidney transplantation, living donor paired exchange and identifying strategies for better HLA matching.

Association of DGF and Early Readmissions on Outcomes Following Kidney Transplantation

Concerns regarding outcomes and early resource utilization are potential deterrents to broader use of kidneys at risk for delayed graft function (DGF). We assessed outcomes specific to kidneys with DGF that required early readmission following transplant. Three groups were identified: 1) recipients with DGF not requiring readmission, 2) recipients with DGF having an isolated readmission, and 3) recipients with DGF requiring ≥2 readmissions. Most recipients either required a single readmission (26.8%, n = 247) or no readmission (56.1%, n = 517); 17.1% (n = 158), had ≥2 readmissions. Recipients requiring ≥2 readmissions were likely to be diabetic (53.8%, p = 0.04) and have longer dialysis vintage (p = 0.01). Duration of DGF was longer with increasing number of readmissions (p < 0.001). There were no differences in patient survival for those with DGF and 0, 1 and ≥2 readmissions (p = 0.13). Graft survival, however, was lower for those with ≥2 readmissions (p < 0.0001). This remained true when accounting for death-censored graft loss (p = 0.0012). Additional subgroup analysis was performed on mate kidneys with and without DGF and mate kidneys, both with DGF, with and without readmissions. For these subgroups, there were no differences in patient or graft survival. As a whole, patients with DGF have excellent outcomes, however, patients with DGF requiring ≥2 readmissions have lower graft survival. A better understanding of recipient variables contributing to multiple readmissions may allow for improvements in the utilization of DGF at-risk kidneys.

Use of Machine Learning Consensus Clustering to Identify Distinct Subtypes of Kidney Transplant Recipients With DGF and Associated Outcomes

Data and transplant community opinion on delayed graft function (DGF), and its impact on outcomes, remains varied. An unsupervised machine learning consensus clustering approach was applied to categorize the clinical phenotypes of kidney transplant (KT) recipients with DGF using OPTN/UNOS data. DGF was observed in 20.9% (n = 17,073) of KT and most kidneys had a KDPI score <85%. Four distinct clusters were identified. Cluster 1 recipients were young, high PRA re-transplants. Cluster 2 recipients were older diabetics and more likely to receive higher KDPI kidneys. Cluster 3 recipients were young, black, and non-diabetic; they received lower KDPI kidneys. Cluster 4 recipients were middle-aged, had diabetes or hypertension and received well-matched standard KDPI kidneys. By cluster, one-year patient survival was 95.7%, 92.5%, 97.2% and 94.3% (p < 0.001); one-year graft survival was 89.7%, 87.1%, 91.6%, and 88.7% (p < 0.001). There were no differences between clusters after accounting for death-censored graft loss (p = 0.08). Clinically meaningful differences in recipient characteristics were noted between clusters, however, after accounting for death and return to dialysis, there were no differences in death-censored graft loss. Greater emphasis on recipient comorbidities as contributors to DGF and outcomes may help improve utilization of DGF at-risk kidneys.

Postoperative statin therapy is not associated with reduced incidence of venous thromboembolic events following kidney transplantation

BACKGROUND

The pleiotropic effects of statin therapy on inflammation and coagulation may reduce the risk of venous thromboembolism. This study evaluated whether statin therapy is associated with decreased venous thromboembolic (VTE) events following kidney transplantation.

METHODS

We performed a retrospective analysis of all primary kidney transplants performed between January 2014 and December 2019 at Mayo Clinic Arizona. Patients were divided into two groups depending on sustained statin therapy during the first year following transplantation. Recipient and donor clinical and demographic data were collected. The primary outcome was admission for symptomatic VTE events (deep vein thrombosis [DVT] or pulmonary embolism [PE]).

RESULTS

Sustained statin therapy in the first year following transplant was observed in 16.1% (n = 223) of 1384 kidney transplants. The overall incidence of VTE events in the year following kidney transplant was 3.8%. VTE occurred in 4.1% of recipients treated with statins and 3.8% of the controls - (hazard ratio [HR] .92, 95% confidence interval [95% CI] .39, 2.21, p = .86). However, there were significant differences between the groups in terms of age, sex, race/ethnicity, body mass index, indication for transplant, diagnosis of diabetes and discharge antiplatelet or anticoagulant therapy. Following sensitivity analysis in which cohort matching was performed to account for these differences, there was no difference in VTE event-free survival (HR .89, 95% CI .41, 1.96, p = .78) or overall survival (HR .54, 95% CI .15, 1.94, p = .35) between patients treated with statins compared to controls.

CONCLUSION

Statin therapy in the year following successful kidney transplant was not associated with a reduction in risk of VTE.

Donation after circulatory death transplant outcomes using livers recovered by local surgeons

Donation after circulatory death (DCD) liver transplantation (LT) outcomes have been attributed to multiple variables, including procurement surgeon recovery techniques. Outcomes of 196 DCD LTs at Mayo Clinic Arizona were analyzed based on graft recovery by a surgeon from our center (transplant procurement team [TPT]) versus a local procurement surgeon (non-TPT [NTPT]). A standard recovery technique was used for all TPT livers. The recovery technique used by the NTPT was left to the discretion of that surgeon. A total of 129 (65.8%) grafts were recovered by our TPT, 67 (34.2%) by the NTPT. Recipient age (p = 0.43), Model for End-Stage Liver Disease score (median 17 vs. 18; p = 0.22), and donor warm ischemia time (median 21.0 vs. 21.5; p = 0.86) were similar between the TPT and NTPT groups. NTPT livers had longer cold ischemia times (6.5 vs. 5.0 median hours; p < 0.001). Early allograft dysfunction (80.6% vs. 76.1%; p = 0.42) and primary nonfunction (0.8% vs. 0.0%; p = 0.47) were similar. Ischemic cholangiopathy (IC) treated with endoscopy occurred in 18.6% and 11.9% of TPT and NTPT grafts (p = 0.23). At last follow-up, approximately half of those requiring endoscopy were undergoing a stent-free trial (58.3% TPT; 50.0% NTPT; p = 0.68). IC requiring re-LT in the first year occurred in 0.8% (n = 1) of TPT and 3.0% (n = 2) of NTPT grafts (p = 0.23). There were no differences in patient (hazard ratio [HR], 1.95; 95% confidence interval [CI], 0.76-5.03; p = 0.23) or graft (HR, 1.99; 95% CI, 0.98-4.09; p = 0.10) survival rates. Graft survival at 1 year was 91.5% for TPT grafts and 95.5% for NTPT grafts. Excellent outcomes can be achieved using NTPT for the recovery of DCD livers. There may be an opportunity to expand the use of DCD livers in the United States by increasing the use of NTPT.

North American Practice-Based Recommendations for Transjugular Intrahepatic Portosystemic Shunts in Portal Hypertension

Complications of portal hypertension, including ascites, gastrointestinal bleeding, hepatic hydrothorax, and hepatic encephalopathy, are associated with significant morbidity and mortality. Despite few high-quality randomized controlled trials to guide therapeutic decisions, transjugular intrahepatic portosystemic shunt (TIPS) creation has emerged as a crucial therapeutic option to treat complications of portal hypertension. In North America, the decision to perform TIPS involves gastroenterologists, hepatologists, and interventional radiologists, but TIPS creation is performed by interventional radiologists. This is in contrast to other parts of the world where TIPS creation is performed primarily by hepatologists. Thus, the successful use of TIPS in North America is dependent on a multidisciplinary approach and technical expertise, so as to optimize outcomes. Recently, new procedural techniques, TIPS stent technology, and indications for TIPS have emerged. As a result, practices and outcomes vary greatly across institutions and significant knowledge gaps exist. In this consensus statement, the Advancing Liver Therapeutic Approaches group critically reviews the application of TIPS in the management of portal hypertension. Advancing Liver Therapeutic Approaches convened a multidisciplinary group of North American experts from hepatology, interventional radiology, transplant surgery, nephrology, cardiology, pulmonology, and hematology to critically review existing literature and develop practice-based recommendations for the use of TIPS in patients with any cause of portal hypertension in terms of candidate selection, procedural best practices and, post-TIPS management; and to develop areas of consensus for TIPS indications and the prevention of complications. Finally, future research directions are identified related to TIPS for the management of portal hypertension.

Decreasing Significance of Early Allograft Dysfunction with Rising Use of Nonconventional Donors

Background and Objectives: Early allograft dysfunction (EAD) is considered a surrogate marker for adverse post-liver transplant (LT) outcomes. With the increasing use of nonconventional donors, EAD has become a more frequent occurrence. Given this background, we aimed to assess the prevalence and impact of EAD in an updated cohort inclusive of both conventional and nonconventional liver allografts. Materials and Methods: Perioperative and one-year outcomes were assessed for a total of 611 LT recipients with and without EAD from Mayo Clinic Arizona. EAD was defined as the presence of one or more of the following: bilirubin > 10 mg/dL on day 7, INR > 1.6 on day 7, or ALT and/or AST > 2000 IU/L within the first 7 days of LT. Results: Within this cohort, 31.8% of grafts (n = 194) came from donation after circulatory death (DCD) donors, 17.7% (n = 108) were nationally shared, 16.4% (n = 100) were allocated as post-cross clamp, and 8.7% contained moderate steatosis. EAD was observed in 52.2% (n = 321) of grafts in the study cohort (79% in DCD grafts and 40% in DBD grafts). EAD grafts had higher donor risk index (DRI) scores (1.9 vs. 1.6, p < 0.0001), were more likely to come from DCD donors (48% vs. 13.8%, p < 0.0001), were regionally allocated (p = 0.003), and had higher cold ischemia times (median 6.0 vs. 5.5 h, p = 0.001). Primary nonfunction events were rare in both groups (1.3% vs. 0.3%, p = 0.22). Post-LT acute kidney injury occurred at a similar frequency in recipients with and without EAD (43.6% vs. 30.3%, p = 0.41), and there were no differences in ICU (median 2 vs. 1 day, p = 0.60) or hospital (6 vs. 5 days, p = 0.24) length of stay. For DCD grafts, the rate of ischemic cholangiopathy was similar in the two groups (14.9% EAD vs. 17.5% no EAD, p = 0.69). One-year patient survival for grafts with and without EAD was 96.0% and 94.1% (HR 1.2, 95% CI 0.7−1.8; p = 0.54); one-year graft survival was 92.5% and 92.1% (HR 1.0, 95% CI 0.7−1.5; p = 0.88). Conclusions: In this cohort, EAD occurred in 52% of grafts. The occurrence of EAD, however, did not portend inferior outcomes. Compared to those without EAD, recipients with EAD had similar post-operative outcomes, as well as one-year patient and graft survival. EAD should be managed supportively and should not be viewed as a deterrent to utilization of non-ideal grafts.

Machine Learning Consensus Clustering of Morbidly Obese Kidney Transplant Recipients in the United States

Background: This study aimed to better characterize morbidly obese kidney transplant recipients, their clinical characteristics, and outcomes by using an unsupervised machine learning approach. Methods: Consensus cluster analysis was applied to OPTN/UNOS data from 2010 to 2019 based on recipient, donor, and transplant characteristics in kidney transplant recipients with a pre-transplant BMI ≥ 40 kg/m2. Key cluster characteristics were identified using the standardized mean difference. Post-transplant outcomes, including death-censored graft failure, patient death, and acute allograft rejection, were compared among the clusters. Results: Consensus clustering analysis identified 3204 kidney transplant recipients with a BMI ≥ 40 kg/m2. In this cohort, five clinically distinct clusters were identified. Cluster 1 recipients were predominantly white and non-sensitized, had a short dialysis time or were preemptive, and were more likely to receive living donor kidney transplants. Cluster 2 recipients were older and diabetic. They were likely to have been on dialysis >3 years and receive a standard KDPI deceased donor kidney. Cluster 3 recipients were young, black, and had kidney disease secondary to hypertension or glomerular disease. Cluster 3 recipients had >3 years of dialysis and received non-ECD, young, deceased donor kidney transplants with a KDPI < 85%. Cluster 4 recipients were diabetic with variable dialysis duration who either received non-ECD standard KDPI kidneys or living donor kidney transplants. Cluster 5 recipients were young retransplants that were sensitized. One-year patient survival in clusters 1, 2, 3, 4, and 5 was 98.0%, 94.4%, 98.5%, 98.7%, and 97%, and one-year death-censored graft survival was 98.1%, 93.0%, 96.1%, 98.8%, and 93.0%, respectively. Cluster 2 had the worst one-year patient survival. Clusters 2 and 5 had the worst one-year death-censored graft survival. Conclusions: With the application of unsupervised machine learning, variable post-transplant outcomes are observed among morbidly obese kidney transplant recipients. Recipients with earlier access to transplant and living donation show superior outcomes. Unexpectedly, reduced graft survival in cluster 3 recipients perhaps underscores socioeconomic access to post-transplant support and minorities being disadvantaged in access to preemptive and living donor transplants. Despite obesity-related concerns, one-year patient and graft survival were favorable in all clusters, and obesity itself should be reconsidered as a hard barrier to kidney transplantation.

Kidney donor profile index and post-transplant health care utilization: Implications for value of transplant care delivery

BACKGROUND

Centers discard high kidney donor profile index (KDPI) allografts, potentially related to delayed graft function and prolonged hospital use by kidney transplant recipients (KTR). We sought to determine whether high KDPI KTRs have excess health care utilization.

METHODS

We conducted a retrospective cohort study from a high-volume center analyzing KTRs from January 3, 2011 to April 12, 2015 (n = 652). We measured differences in hospital use, emergency visits, and outpatient visits within the first 90 days between low (≤85%) versus high KDPI (>85%) KTRs, as well as long-term graft function and patient survival.

RESULTS

High (n = 107) and low KDPI (n = 545) KTRs had similar length of stay (median = 3 days, P = .66), and readmission rates at 7, 30, and 90 days after surgery (all, P > .05). High KDPI kidneys were not associated with excess utilization of the hospital, emergency services, outpatient transplant clinics, or ambulatory infusion visits on univariate or multivariate analysis (all, P > .05). Low KDPI KTRs had significantly better eGFR at 2 years (Low vs. High KDPI: 60.35 vs. 41.54 ml/min, P < .001), but similar 3-year patient and graft survival (both, P > .09).

CONCLUSIONS

High and low KDPI KTRs demonstrated similar 90-day risk-adjusted health care utilization, which should encourage use of high KDPI kidneys.

Use of Machine Learning Consensus Clustering to Identify Distinct Subtypes of Black Kidney Transplant Recipients and Associated Outcomes

Importance

Among kidney transplant recipients, Black patients continue to have worse graft function and reduced patient and graft survival. Better understanding of different phenotypes and subgroups of Black kidney transplant recipients may help the transplant community to identify individualized strategies to improve outcomes among these vulnerable groups.

Objective

To cluster Black kidney transplant recipients in the US using an unsupervised machine learning approach.

Design, Setting, and Participants

This cohort study performed consensus cluster analysis based on recipient-, donor-, and transplant-related characteristics in Black kidney transplant recipients in the US from January 1, 2015, to December 31, 2019, in the Organ Procurement and Transplantation Network/United Network for Organ Sharing database. Each cluster's key characteristics were identified using the standardized mean difference, and subsequently the posttransplant outcomes were compared among the clusters. Data were analyzed from June 9 to July 17, 2021.

Exposure

Machine learning consensus clustering approach.

Main Outcomes and Measures

Death-censored graft failure, patient death within 3 years after kidney transplant, and allograft rejection within 1 year after kidney transplant.

Results

Consensus cluster analysis was performed for 22 687 Black kidney transplant recipients (mean [SD] age, 51.4 [12.6] years; 13 635 men [60%]), and 4 distinct clusters that best represented their clinical characteristics were identified. Cluster 1 was characterized by highly sensitized recipients of deceased donor kidney retransplants; cluster 2, by recipients of living donor kidney transplants with no or short prior dialysis; cluster 3, by young recipients with hypertension and without diabetes who received young deceased donor transplants with low kidney donor profile index scores; and cluster 4, by older recipients with diabetes who received kidneys from older donors with high kidney donor profile index scores and extended criteria donors. Cluster 2 had the most favorable outcomes in terms of death-censored graft failure, patient death, and allograft rejection. Compared with cluster 2, all other clusters had a higher risk of death-censored graft failure and death. Higher risk for rejection was found in clusters 1 and 3, but not cluster 4.

Conclusions and Relevance

In this cohort study using an unsupervised machine learning approach, the identification of clinically distinct clusters among Black kidney transplant recipients underscores the need for individualized care strategies to improve outcomes among vulnerable patient groups.

Duration of delayed graft function and its impact on graft outcomes in deceased donor kidney transplantation

BACKGROUND

There is controversy regarding the impact of delayed graft function (DGF) on kidney transplant outcomes. We hypothesize that the duration of DGF, rather than DGF itself, is associated with long-term kidney graft function.

METHODS

We analyzed all deceased donor kidney transplants (DDKT) done at our center between 2008 to 2020. We determined factors associated with DGF duration. DGF duration was assessed at three 14-day intervals: < 14 DGF days, 14-27 DGF days, > 28 DGF days. We studied the impact of DGF duration on survival and graft function and resource utilization, including hospital length of stay and readmissions.

RESULTS

1714 DDKT recipients were included, 59.4% (n = 1018) had DGF. The median DGF duration was 10 days IQR (6,15). The majority of recipients (95%) had resolution of DGF within 28 days. Donor factors associated with DGF days were longer cold ischemia time, donor on inotropes, older age, donation after circulatory death, higher terminal creatinine, and hypertension. Recipient factors associated with increased DGF duration included male sex, length on dialysis before transplant, and higher body mass index. There were no differences in acute rejection events or interstitial fibrosis progression by 4 months when comparing DGF days. The median length of stay was 3 days. However, readmissions increased with increasing DGF duration. Death-censored graft survival was not associated with the length of DGF except when DGF lasted > 28 days.

CONCLUSIONS

Inferior graft survival was observed only in recipients of DDKT with DGF lasting beyond 28 days. DGF lasting < 28 days had no impact on graft survival. Duration of DGF, rather than DGF itself, is associated with graft survival.

TRIAL REGISTRATION

Retrospective study approved by Mayo Clinic IRB number ID: 20-011561.

Alloantibodies after simultaneous liver-kidney transplant: A story of primary nonfunction, retransplantation, and antibody-mediated rejection

Simultaneous liver-kidney transplant (SLKT) in the presence of antihuman leukocyte antigen (HLA) donor-specific antibodies (DSA) is a well-accepted practice. Herein, we describe the evolution of alloantibodies in a patient who received an SLKT. The pre-SLKT serum sample showed multiple strong DSA. As expected, all DSA cleared in a sample collected 4 days after the SLKT. Because of the primary nonfunction of the liver in the SLKT, the patient had a second liver transplant 4 days later. An abrupt increase in DSA levels against the kidney was detected 10 days after the second liver transplant. These DSA were refractory to treatment, and the transplanted kidney was lost due to antibody-mediated rejection (AMR). A detailed study of the HLA epitopes recognized by DSA and, after normalization with third-party alloantibodies to address the effect of multiple transfusions and liver allograft neutralization, showed that the elimination of these antibodies depended on the HLA antigens expressed by the transplanted liver cells. The return of DSA after removal of the first transplanted liver was associated with AMR in the transplanted kidney.

Solid Organ Transplantation From SARS-CoV-2-infected Donors to Uninfected Recipients: A Single-center Experience

BACKGROUND

The risk of donor-derived severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in solid organ (heart, lung, liver, kidney, pancreas, and intestine) transplant recipients is poorly understood. Since hematogenous transmission of SARS-CoV-2 has not been documented to date, nonlung solid organs might be suitable for transplantation since they likely portend a low risk of viral transmission.

METHODS

Abdominal solid organs from SARS-CoV-2-infected donors were transplanted into uninfected recipients.

RESULTS

Between April 18, 2021, and October 30, 2021, we performed transplants of 2 livers, 1 simultaneous liver and kidney, 1 kidney, and 1 simultaneous kidney and pancreas from SARS-CoV-2-infected donors into 5 uninfected recipients. None of the recipients developed SARS-CoV-2 infection or coronavirus disease 2019, and when tested, allograft biopsies showed no evidence of SARS-CoV-2 RNA.

CONCLUSIONS

Transplanting nonlung organs from SARS-CoV-2-infected donors into uninfected recipients demonstrated no evidence of virus transmission.

In-hospital mortality of hepatorenal syndrome in the United States: Nationwide inpatient sample

BACKGROUND

Hepatorenal syndrome (HRS) is a life-threatening condition among patients with advanced liver disease. Data trends specific to hospital mortality and hospital admission resource utilization for HRS remain limited.

AIM

To assess the temporal trend in mortality and identify the predictors for mortality among hospital admissions for HRS in the United States.

METHODS

We used the National Inpatient Sample database to identify an unweighted sample of 4938 hospital admissions for HRS from 2005 to 2014 (weighted sample of 23973 admissions). The primary outcomes were temporal trends in mortality as well as predictors for hospital mortality. We estimated odds ratios from multi-level mixed effect logistic regression to identify patient characteristics and treatments associated with hospital mortality.

RESULTS

Overall hospital mortality was 32%. Hospital mortality decreased from 44% in 2005 to 24% in 2014 (P < 0.001), while there was an increase in the rate of liver transplantation (P = 0.02), renal replacement therapy (P < 0.001), length of hospital stay (P < 0.001), and hospitalization cost (P < 0.001). On multivariable analysis, older age, alcohol use, coagulopathy, neurological disorder, and need for mechanical ventilation predicted higher hospital mortality, whereas liver transplantation, transjugular intrahepatic portosystemic shunt, and abdominal paracentesis were associated with lower hospital mortality.

CONCLUSION

Although there was an increase in resource utilizations, hospital mortality among patients admitted for HRS significantly improved. Several predictors for hospital mortality were identified.

Feature Importance of Acute Rejection among Black Kidney Transplant Recipients by Utilizing Random Forest Analysis: An Analysis of the UNOS Database

Background: Black kidney transplant recipients have worse allograft outcomes compared to White recipients. The feature importance and feature interaction network analysis framework of machine learning random forest (RF) analysis may provide an understanding of RF structures to design strategies to prevent acute rejection among Black recipients. Methods: We conducted tree-based RF feature importance of Black kidney transplant recipients in United States from 2015 to 2019 in the UNOS database using the number of nodes, accuracy decrease, gini decrease, times_a_root, p value, and mean minimal depth. Feature interaction analysis was also performed to evaluate the most frequent occurrences in the RF classification run between correlated and uncorrelated pairs. Results: A total of 22,687 Black kidney transplant recipients were eligible for analysis. Of these, 1330 (6%) had acute rejection within 1 year after kidney transplant. Important variables in the RF models for acute rejection among Black kidney transplant recipients included recipient age, ESKD etiology, PRA, cold ischemia time, donor age, HLA DR mismatch, BMI, serum albumin, degree of HLA mismatch, education level, and dialysis duration. The three most frequent interactions consisted of two numerical variables, including recipient age:donor age, recipient age:serum albumin, and recipient age:BMI, respectively. Conclusions: The application of tree-based RF feature importance and feature interaction network analysis framework identified recipient age, ESKD etiology, PRA, cold ischemia time, donor age, HLA DR mismatch, BMI, serum albumin, degree of HLA mismatch, education level, and dialysis duration as important variables in the RF models for acute rejection among Black kidney transplant recipients in the United States.

Successful outcomes with transplanting kidneys from deceased donors with acute kidney injuryon temporary renal replacement therapy

BACKGROUND AND OBJECTIVES

We aimed to determine outcomes with transplanting kidneys from deceased donors with severe acute kidney injury requiring acute renal replacement therapy (RRT).

MATERIALS AND METHODS

A total of 172 recipients received a kidney from donors with acute kidney injury stage 3 (AKIN3) requiring RRT. We compared the study group to 528 recipients who received a kidney from donors with AKIN stage 3 not on RRT and 463 recipients who received < 85% Kidney Donor Profile Index (KDPI) AKIN stage 0 kidney.

RESULTS

The study group donors were younger compared to the 2 control groups. Despite higher DGF in the study group, the length of hospital stay and acute rejection were similar. Death censored graft survival (96% AKIN3-RRT vs. 97%AKIN3 no RRT vs. 96% KDPI < 85% AKIN0, P = 0.26) and patient survival with functioning graft at 1 year (95% across all groups, P = 0.402) were similar. The estimated glomerular filtration rate were similar across the 3 groups after first month. Interstitial fibrosis and tubular atrophy score ≥ 2 on protocol biopsy at time 0, 4 and 12 months were similar. Primary nonfunction was rare and associated with high KDPI.

CONCLUSIONS

Transplanting selected kidneys from deceased donors with AKIN3 requiring RRT is safe and has good outcomes.

Outcomes of Kidney Transplant Recipients with Sickle Cell Disease: An Analysis of the 2000-2019 UNOS/OPTN Database

Background: Lower patient survival has been observed in sickle cell disease (SCD) patients who go on to receive a kidney transplant. This study aimed to assess the post-transplant outcomes of SCD kidney transplant recipients in the contemporary era. Methods: We used the OPTN/UNOS database to identify first-time kidney transplant recipients from 2010 through 2019. We compared patient and allograft survival between recipients with SCD (n = 105) vs. all other diagnoses (non-SCD, n = 146,325) as the reported cause of end-stage kidney disease. We examined whether post-transplant outcomes improved among SCD in the recent era (2010–2019), compared to the early era (2000–2009). Results: After adjusting for differences in baseline characteristics, SCD was significantly associated with lower patient survival (HR 2.87; 95% CI 1.75–4.68) and death-censored graft survival (HR 1.98; 95% CI 1.30–3.01), compared to non-SCD recipients. The lower patient survival and death-censored graft survival in SCD recipients were consistently observed in comparison to outcomes of recipients with diabetes, glomerular disease, and hypertension as the cause of end-stage kidney disease. There was no significant difference in death censored graft survival (HR 0.99; 95% CI 0.51–1.73, p = 0.98) and patient survival (HR 0.93; 95% CI 0.50–1.74, p = 0.82) of SCD recipients in the recent versus early era. Conclusions: Patient and allograft survival in SCD kidney recipients were worse than recipients with other diagnoses. Overall SCD patient and allograft outcomes in the recent era did not improve from the early era. The findings of our study should not discourage kidney transplantation for ESKD patients with SCD due to a known survival benefit of transplantation compared with remaining on dialysis. Urgent future studies are needed to identify strategies to improve patient and allograft survival in SCD kidney recipients. In addition, it may be reasonable to assign risk adjustment for SCD patients.

Correlation of Chronic Histologic Changes on Preimplantation Frozen Section Biopsy With Transplant Outcomes After Deceased Donor Kidney Transplantation

CONTEXT.—

It is unclear if preimplantation frozen section biopsy correlates with outcomes after deceased donor kidney transplantation.

OBJECTIVE.—

To assess if chronic histologic changes on the preimplant frozen section correlates with graft loss and estimated glomerular filtration rate independently of kidney donor profile index (KDPI).

DESIGN.—

Seven hundred three preimplantation biopsies were reviewed and a Banff sum score was calculated using glomerular sclerosis, interstitial fibrosis, vascular intimal thickening, and arteriolar hyalinosis. The posttransplant outcomes were compared for preimplantation biopsy Banff sum 0-1, 2-3, and 4-9. The cohort was also stratified by KDPI 85 or less versus more than 85.

RESULTS.—

For the entire biopsy cohort, graft survival, estimated glomerular filtration rate at 1 year and chronic changes on a 1-year posttransplant biopsy were superior in the group with preimplantation Banff sum 0-1. After stratifying by KDPI, the Banff sum no longer correlated with graft survival. In a univariate mode, using the Banff sum score as a continuous variable, a higher Banff sum score was significantly associated with graft failure (P = .03); however, after adjusting the KDPI, the Banff sum score no longer correlated with graft failure (P = .45). The 1-year estimated glomerular filtration rate and 1 year biopsy changes were superior in the group with Banff sum 0-1 only in the cohort with KDPI 85 or less.

CONCLUSIONS.—

In donor kidneys used for transplant, preimplantation biopsy chronic changes correlate with estimated glomerular filtration rate and biopsy findings at 1 year, but biopsies with mostly mild chronicity and sum scores less than or equal to 5 did not impact graft survival beyond KDPI.

Overcoming Mismatch Concerns for Adult Recipients of Small Pediatric Deceased Donor Kidneys

BACKGROUND

Kidneys from very young pediatric donors continue to be underutilized. To reduce discard, the Organ Procurement and Transplantation Network (OPTN) policy was recently updated to allow kidneys from donors weighing <18 kg to be recovered en bloc.

METHODS

We reviewed our center's experience with kidney transplantation in adult recipients of <18 kg pediatric donor kidneys to assess renal function outcomes specific to solitary vs en bloc usage.

RESULTS

The majority of <18 kg donors were used en bloc (n = 39, 72.2% vs n = 15, 27.8%). Donor weight (kg) was similar between the 2 groups (12.3 ± 3.2 vs 14.1 ± 2.5, P = .05). Recipient weight was lower in the solitary kidney group (P = .01). Both groups had a similar donor-to-recipient body weight ratio (0.24 ± 0.3 vs 0.18 ± 0.3, P = .51). The solitary kidney group had a lower estimated glomerular filtration rate at 1 (56.9 ± 24.3 vs 81.8 ± 24.8, P = .01) and 2 years (72 ± 18.6 vs 93.7 ± 21.6, P = .03). By 2 years, both groups had an average estimated glomerular filtration rate >60 mL/min. Kidney allograft growth occurred in both groups, with the largest increase occurring the first month posttransplant (11.9%, 18.6%, P < .0001).

CONCLUSION

For pediatric donors weighing <18 kg, improvements in renal function continue beyond the first posttransplant year. Risk for hyperfiltration injury appears low and renal mass-recipient mass matching is useful in guiding decision-making for solitary vs en bloc utilization.

Transplant outcomes using kidneys from high KDPI acute kidney injury donors

Kidney transplant (KT) outcomes from high kidney donor profile index (KDPI ≥85%) donors with acute kidney injury (AKI) remain underreported. KT from 172 high KDPI Acute Kidney Injury Network (AKIN) stage 0-1 donors and 76 high KDPI AKIN stage 2-3 donors from a single center were retrospectively assessed. The AKIN 2-3 cohort had more delayed graft function (71% vs. 37%, p < .001). At one year, there were no differences in the estimated glomerular filtration rate (44 ± 17 vs. 46 ± 18, p = .42) or fibrosis on protocol biopsy (ci, p = .85). Donor terminal creatinine (p = .59) and length of delayed graft function (p = .39) did not impact one-year eGFR. There were more primary nonfunction (PNF) events in the high KDPI AKIN 2-3 group (5.3% vs. 0.6%, p = .02). With a median follow-up of 3.8 years, one-year death-censored graft failure was 3.5% for AKIN 0-1 and 14.5% for AKIN 2-3 (HR 2.40, 95% CI 1.24-4.63, p = .01). Although AKIN stage 2-3 high KDPI kidneys had comparable one-year eGFR to AKIN stage 0-1 high KDPI kidneys, there were more PNF occurrences and one-year death-censored graft survival was reduced. Given these findings, additional precautions should be undertaken when assessing and utilizing kidneys from severe AKI high KDPI donors.

Hepatitis E in solid organ transplant recipients: A systematic review and meta-analysis

BACKGROUND

Hepatitis E virus (HEV) infection is underdiagnosed due to the use of serological assays with low sensitivity. Although most patients with HEV recover completely, HEV infection among patients with pre-existing chronic liver disease and organ-transplant recipients on immunosuppressive therapy can result in decompensated liver disease and death.

AIM

To demonstrate the prevalence of HEV infection in solid organ transplant (SOT) recipients.

METHODS

We searched Ovid MEDLINE, EMBASE, and the Cochrane Library for eligible articles through October 2020. The inclusion criteria consisted of adult patients with history of SOT. HEV infection is confirmed by either HEV-immunoglobulin G, HEV-immunoglobulin M, or HEV RNA assay.

RESULTS

Of 563 citations, a total of 22 studies (n = 4557) were included in this meta-analysis. The pooled estimated prevalence of HEV infection in SOT patients was 20.2% [95% confidence interval (CI): 14.9-26.8]. The pooled estimated prevalence of HEV infection for each organ transplant was as follows: liver (27.2%; 95%CI: 20.0-35.8), kidney (12.8%; 95%CI: 9.3-17.3), heart (12.8%; 95%CI: 9.3-17.3), and lung (5.6%; 95%CI: 1.6-17.9). Comparison across organ transplants demonstrated statistical significance (Q = 16.721, P = 0.002). The subgroup analyses showed that the prevalence of HEV infection among SOT recipients was significantly higher in middle-income countries compared to high-income countries. The pooled estimated prevalence of de novo HEV infection was 5.1% (95%CI: 2.6-9.6) and the pooled estimated prevalence of acute HEV infection was 4.3% (95%CI: 1.9-9.4).

CONCLUSION

HEV infection is common in SOT recipients, particularly in middle-income countries. The prevalence of HEV infection in lung transplant recipients is considerably less common than other organ transplants. More studies examining the clinical impacts of HEV infection in SOT recipients, such as graft failure, rejection, and mortality are warranted.

Outcomes of kidney retransplantation in recipients with prior posttransplant lymphoproliferative disorders: An analysis of the 2000-2019 UNOS/OPTN database

This study utilized the UNOS database to assess clinical outcomes after kidney retransplantation in patients with a history of posttransplant lymphoproliferative disease (PTLD). Among second kidney transplant patients from 2000 to 2019, 254 had history of PTLD in their first kidney transplant, whereas 28,113 did not. After a second kidney transplant, PTLD occurred in 2.8% and 0.8% of patients with and without history of PTLD, respectively (p = .001). Over a median follow-up time of 4.5 years after a second kidney transplant, 5-year death-censored graft failure was 9.5% vs. 12.6% (p = .21), all-cause mortality was 8.3% vs. 11.8% (p = .51), and 1-year acute rejection was 11.0% vs. 9.3% (p = .36) in the PTLD vs. non-PTLD groups, respectively. There was no significant difference in death-censored graft failure, mortality, and acute rejection between PTLD and non-PTLD groups in adjusted analysis and after propensity score matching. We conclude that graft survival, patient survival, and acute rejection after kidney retransplantation are comparable between patients with and without history of PTLD, but PTLD occurrence after kidney retransplantation remains higher in patients with history of PTLD.

Simultaneous liver-kidney transplantation from donation after cardiac death donors: an updated perspective

Outcomes of both donation after cardiac death (DCD) liver and kidney transplants are improving. Experience in simultaneous liver-kidney transplant (SLK) using DCD donors, however, remains limited. In an updated cohort (2010-2018), outcomes of 30 DCD SLK and 131 donation after brain death (DBD) SLK from Mayo Clinic Arizona and Mayo Clinic Minnesota were reviewed. The Model for End-Stage Liver Disease score was lower in the DCD SLK group (23 vs 29, P = .01). Kidney delayed graft function (DGF) rates were similar between the 2 groups (P = .11), although the duration of DGF was longer for DCD SLK recipients (20 vs 4 days, P = .01). Liver allograft (93.3% vs 93.1%, P = .29), kidney allograft (93.3% vs 93.1%, P = .91), and patient (96.7% vs 95.4%, P = .70) 1-year survival rates were similar. At 1 year, there were no differences in the estimated glomerular filtration rate (57.7 ± 18.2 vs 56.3 ± 17.7, P = .75) or progression of fibrosis (ci) on protocol kidney biopsy (P = .67). A higher incidence of biliary complications was observed in the DCD SLK group, with ischemic cholangiopathy being the most common (10.0% vs 0.0%, P = .03). The majority of biliary complications resolved with endoscopic management. With appropriate selection, DCD SLK recipients can have results equivalent to those of DBD SLK recipients.

Early technical pancreas failure in Simultaneous Pancreas-Kidney Recipients does not impact renal allograft outcomes

Early pancreas loss in simultaneous pancreas-kidney (SPK) transplants has been associated with longer perioperative recovery and reduced kidney allograft function. We assessed the impact of early pancreas allograft failure on transplant outcomes in a contemporary cohort of SPK patients (n = 218). Early pancreas allograft loss occurred in 12.8% (n = 28) of recipients. Delayed graft function (DGF) was more common (21.4% vs. 7.4%, p = 0.03) in the early pancreas loss group, but there were no differences in hospital length of stay (median 6.5 vs. 7.0, p = 0.22), surgical wound complications (p = 0.12), or rejection episodes occurring in the first year (p = 0.87). Despite differences in DGF, both groups had excellent renal function at 1 year post-transplant (eGFR 64.1 ± 20.8 vs. 65.8 ± 22.9, p = 0.75). There were no differences in patient (HR 0.58, 95% CI 0.18-1.87, p = 0.26) or kidney allograft survival (HR 0.84, 95% CI 0.23-3.06, p = 0.77). One- and 2-year protocol kidney biopsies were comparable between the groups and showed minimal chronic changes; the early pancreas loss group showed more cv changes at 2 years (p = 0.04). Current data demonstrate good outcomes and excellent kidney allograft function following early pancreas loss.

Robot Assisted Renal Allograft Nephrectomy: Initial Case Series and Description of Technique

OBJECTIVE

To evaluate the outcomes and perioperative complication rates following robot- assisted transplant nephrectomy ((RATN).

METHODS

All patients who underwent RATN at our institution were included. No exclusion criteria were applied. Clinical records were retrospectively reviewed and reported. This included preoperative, intraoperative, and postoperative outcomes. Complications were reported utilizing the Clavien-Dindo classification system. Descriptive statistics were reported using frequencies and percentages for categorical variables, means and standard deviation for continuous variables.

RESULTS

Between July 2014 and April 2018, 15 patients underwent RATN. Most patients had the transplant in the right iliac fossa (13/15). Ten patients underwent a concomitant procedure. The total operative time for the entire cohort was 336 (±102) minutes (including cases who had concomitant procedures) and 259 (±46 minutes) when cases with concomitant procedures were excluded. Mean estimated blood loss was 383 (±444) mL. Postoperatively, 3 patients required blood transfusion. Average hospital stay was 4 (±2.7) days. Most patients had finding consistent with graft rejection on final pathology. There were 5 complications; 3 of which were minor (grade 2 = 2 and grade 3 = 1); one patient had a wound infection requiring dressing (3A) and one patient died due to pulmonary embolism following discharge. Limitations include small series and retrospective nature of the study.

CONCLUSION

This case series demonstrate that RATN is technically feasible. With continued experience and larger case series, the robotic approach may provide a minimally invasive alternative to open allograft nephrectomy.

Endarterectomy for Iliac Occlusive Disease during Kidney Transplantation: A Multicenter Experience

Little is known about the surgical challenges and outcomes of kidney transplantation (KT) in the face of severe iliac occlusive disease (IOD). We aim to examine our institution's experience and outcomes compared with all KT patients. Retrospective review of our multi-institutional transplant database identified patients with IOD requiring vascular surgery involvement for iliac artery endarterectomy at time of KT from 2000 to 2018. Clinical data, imaging studies, and surgical outcomes of 22 consecutive patients were reviewed. Our primary end-point was allograft survival. Secondary end-points included mortality and perioperative complications. A total of 6,757 KT were performed at our three sites (Florida, Arizona, and Minnesota); there were 22 (0.32%) patients receiving a KT with concomitant IOD requiring iliac artery endarterectomy. Mean patient age was 61.45 ± 7 years. There were 13 (59.1%) male patients. The most common etiology of renal failure was diabetic nephropathy in 10 patients (45.5%) followed by a combination of hypertensive/diabetic nephropathy in five patients (22.7%), and hypertensive nephrosclerosis in three patients (13.6%). The majority ( n  = 16, 72.7%) of patients received renal allografts from deceased donors and six (27.3%) were recipients from living donors. Mean time from dialysis to transplantation was 2.9 ± 2.9 years. Mean follow-up was 3.5 ± 2.5 years. Mean length of hospital stay was 6.3 ± 4.3 days (range: 3-18 days). Graft loss within 90 days occurred in two (9.1%) patients, one due to renal vein thrombosis and another due to acute tubular necrosis. Overall allograft survival was 90.1% at 1-year and 86.4% at 3-year follow-up. Overall mortality occurred in 6 (27.3%) patients. Perioperative complications (Clavien-Dindo Grade 2-4) occurred in 13 (59.1%) patients, including 10 (45.5%) with acute blood loss anemia requiring transfusion, 2 (9.1%) reoperations for hematoma evacuation, 1 (4.5%) ischemic colitis requiring total abdominal colectomy, and 1 (4.5%) renal vein thrombosis requiring nephrectomy. IOD patients selected for KT are not common and although challenging, they have similar outcomes to our standard KT patients. The 1- and 3-year allograft survivals were 90.1 and 86.4% versus 96.0 and 90.3% in the general KT patient population. With these excellent outcomes, we recommend expanding the criteria for KT to include patients with IOD with prior vascular surgery consultation to prevent progression of IOD or prevention of wait list removal in select patients who are otherwise good candidates for KT.

Transplanting kidneys from donation after cardiac death donors with acute kidney injury

Donation after cardiac death (DCD) and acute kidney injury (AKI) donors have historically been considered independent risk factors for delayed graft function (DGF), allograft failure, and inferior outcomes. With growing experience, updated analyses have shown good outcomes. There continues to be limited data, however, on outcomes specific to DCD donors who have AKI. Primary outcomes for this study were post-kidney transplant patient and allograft survival comparing two donor groups: DCD AKIN stage 2-3 and DBD AKIN stage 2-3. In comparing these groups, there were no short- or long-term differences in patient (hazard ratio [HR] 1.07, 95% confidence interval [CI] 0.54-1.93, P = .83) or allograft survival (HR 1.47, 95% CI 0.64-2.97, P = .32). In multivariate models, the DCD/DBD status had no significant impact on the estimated GFR (eGFR) at 1 (P = .38), 2 (P = .60), and 3 years (P = .52). DGF (57.9% vs 67.9%, P = .09), rejection (12.1% vs 13.9%, P = .12), and progression of interstitial fibrosis/tubular atrophy (IFTA) on protocol biopsy (P = .16) were similar between the two groups. With careful selection, good outcomes can be achieved utilizing severe AKI DCD kidneys. Historic concerns regarding primary nonfunction, DGF resulting in interstitial fibrosis and rejection, and inferior outcomes were not observed. Given the ongoing organ shortage, increased effort should be undertaken to further utilize these donors.