Recipient donor sex combinations in solid organ transplantation and impact on clinical outcome: A scoping review.

INTRODUCTION: Solid organ transplantation (SOT) is a lifesaving treatment for end-stage organ failure. Although many factors affect the success of organ transplantation, recipient and donor sex are important biological factors influencing transplant outcome. However, the impact of the four possible recipient and donor sex combinations (RDSC) on transplant outcome remains largely unclear. METHODS: A scoping review was carried out focusing on studies examining the association between RDSC and outcomes (mortality, graft rejection, and infection) after heart, lung, liver, and kidney transplantation. All studies up to February 2023 were included. RESULTS: Multiple studies published between 1998 and 2022 show that RDSC is an important factor affecting the outcome after organ transplantation. Male recipients of SOT have a higher risk of mortality and graft failure than female recipients. Differences regarding the causes of death are observed. Female recipients on the other hand are more susceptible to infections after SOT. CONCLUSION: Differences in underlying illnesses as well as age, immunosuppressive therapy and underlying biological mechanisms among male and female SOT recipients affect the post-transplant outcome. However, the precise mechanisms influencing the interaction between RDSC and post-transplant outcome remain largely unclear. A better understanding of how to identify and modulate these factors may improve outcome, which is particularly important in light of the worldwide organ shortage. An analysis for differences of etiology and causes of graft loss or mortality, respectively, is warranted across the RDSC groups. PRACTITIONER POINTS: Recipient and donor sex combinations affect outcome after solid organ transplantation. While female recipients are more susceptible to infections after solid organ transplantation, they have higher overall survival following SOT, with causes of death differing from male recipients. Sex-differences should be taken into account in the post-transplant management.

Ex-situ graft reduction (H67) during hypothermic oxygenated perfusion to prevent large-for-size syndrome in liver transplantation-A technical report.

In this report, we discuss several technical and anatomical details of ex-situ H67 reduction of liver grafts during hypothermic oxygenated perfusion to prevent large-for-size syndrome in the case of anthropometric graft-recipient mismatch.

Optimizing graft-recipient size matching in adolescent liver transplantation: Don't forget ex situ right posterior sectionectomy.

BACKGROUND: Graft-recipient size matching is a major challenge in pediatric liver transplantation, especially for adolescent recipients. Indeed, adolescents have the lowest transplantation rate among pediatric recipients, despite prioritization policies and the use of split grafts. In case of an important graft-recipient size mismatch, ex situ graft reduction with right posterior sectionectomy (RPS) may optimize the available donor pool to benefit adolescent recipients. METHODS: We present three cases of liver graft reduction with ex situ RPS for adolescent recipients. The surgical strategy was guided by GRWR (graft/recipient weight ratio), GW/RAP (right anteroposterior distance ratio), and CT-scan volumetric and anthropometric evaluation. RESULTS: Recipients were 12, 13, and 14-year-old and weighed 32, 47, and 35 kg, respectively. All liver grafts were procured from brain-dead donors with a donor/recipient weight ratio >1.5. RPS was performed ex situ, removing 20% of the total liver volume leading to a decrease of the GRWR <4% and the GW/RAP <100 g/cm in each case. All three reduced grafts were successfully transplanted with a static cold storage time ranging from 390 to 510 min without the need for delayed abdominal closure. We did not observe any primary non-function, vascular complication, or delayed graft function with a median follow-up of 6 months. One biliary anastomotic stenosis occurred which required surgical treatment. CONCLUSION: Ex situ liver graft reduction with RPS allowed for successful transplantation in case of anthropometric graft-recipient size mismatch in adolescent liver transplant candidates. Although the use of split grafts remains the gold standard, RPS should be acknowledged as a way to optimize the donor pool, especially for adolescent recipients.

Artificial intelligence and liver transplantation: Looking for the best donor-recipient pairing.

Decision-making based on artificial intelligence (AI) methodology is increasingly present in all areas of modern medicine. In recent years, models based on deep-learning have begun to be used in organ transplantation. Taking into account the huge number of factors and variables involved in donor-recipient (D-R) matching, AI models may be well suited to improve organ allocation. AI-based models should provide two solutions: complement decision-making with current metrics based on logistic regression and improve their predictability. Hundreds of classifiers could be used to address this problem. However, not all of them are really useful for D-R pairing. Basically, in the decision to assign a given donor to a candidate in waiting list, a multitude of variables are handled, including donor, recipient, logistic and perioperative variables. Of these last two, some of them can be inferred indirectly from the team's previous experience. Two groups of AI models have been used in the D-R matching: artificial neural networks (ANN) and random forest (RF). The former mimics the functional architecture of neurons, with input layers and output layers. The algorithms can be uni- or multi-objective. In general, ANNs can be used with large databases, where their generalizability is improved. However, they are models that are very sensitive to the quality of the databases and, in essence, they are black-box models in which all variables are important. Unfortunately, these models do not allow to know safely the weight of each variable. On the other hand, RF builds decision trees and works well with small cohorts. In addition, they can select top variables as with logistic regression. However, they are not useful with large databases, due to the extreme number of decision trees that they would generate, making them impractical. Both ANN and RF allow a successful donor allocation in over 80% of D-R pairing, a number much higher than that obtained with the best statistical metrics such as model for end-stage liver disease, balance of risk score, and survival outcomes following liver transplantation scores. Many barriers need to be overcome before these deep-learning-based models can be included for D-R matching. The main one of them is the resistance of the clinicians to leave their own decision to autonomous computational models.

Crossroads in Liver Transplantation: Is Artificial Intelligence the Key to Donor-Recipient Matching?

Liver transplantation outcomes have improved in recent years. However, with the emergence of expanded donor criteria, tools to better assist donor-recipient matching have become necessary. Most of the currently proposed scores based on conventional biostatistics are not good classifiers of a problem that is considered "unbalanced." In recent years, the implementation of artificial intelligence in medicine has experienced exponential growth. Deep learning, a branch of artificial intelligence, may be the answer to this classification problem. The ability to handle a large number of variables with speed, objectivity, and multi-objective analysis is one of its advantages. Artificial neural networks and random forests have been the most widely used deep classifiers in this field. This review aims to give a brief overview of D-R matching and its evolution in recent years and how artificial intelligence may be able to provide a solution.

Analysis of factors associated with discrepancies between predicted and observed liver weight in liver transplantation.

BACKGROUND: Even using predictive formulas based on anthropometrics in about 30% of subjects, liver weight (LW) cannot be predicted with a ≤20% margin of error. We aimed to identify factors associated with discrepancies between predicted and observed LW. METHODS: In 500 consecutive liver grafts, we tested LW predictive performance using 17 formulas based on anthropometric characteristics. Hashimoto's formula (961.3 × BSA_D-404.8) was associated with the lowest mean absolute error and used to predict LW for the entire cohort. Clinical factors associated with a ≥20% margin of error were identified in a multivariable analysis after propensity score matching (PSM) of donors with similar anthropometric characteristics. RESULTS: The total LW was underestimated with a ≥20% margin of error in 53/500 (10.6%) donors and overestimated in 62/500 (12%) donors. After PSM analysis, ages ≥ 65, (OR = 3.21; CI95% = 1.63-6.31; P = .0007), age ≤ 30 years, (OR = 2.92; CI95% = 1.15-7.40; P = .02), and elevated gamma-glutamyltransferase (GGT) levels (OR = 0.98; CI95% = 0.97-0.99; P = .006), influenced the risk of LW overestimation. Age ≥ 65 years, (OR = 5.98; CI95% = 2.28-15.6; P = .0002), intensive care unit (ICU) stay with ventilation > 7 days, (OR = 0.32; CI95% = 0.12-0.85; P = .02) and waist circumference increase (OR = 1.02; CI95% = 1.00-1.04; P = .04) were factors associated with LW underestimation. CONCLUSIONS: Increased waist circumference, age, prolonged ICU stay with ventilation, elevated GGT were associated with an increase in the margin of error in LW prediction. These factors and anthropometric characteristics could help transplant surgeons during the donor-recipient matching process.

Surgical complications in pediatric kidney transplantation-Incidence, risk factors, and effects on graft survival: A retrospective single-center study.

The field of pediatric kidney transplantation remains challenging due to an ongoing lack of size-matched grafts and anatomical peculiarities. In the current study, we investigated the incidence of surgical complications in pediatric recipients, with a focus on risk factors and effects on graft outcome. We retrospectively reviewed all 2386 kidney transplantations at our institution from January 2005 until December 2018. Of these, 221 transplants were performed in pediatric recipients, defined as under the age of 18 years. Donor-recipient body surface area ratios were calculated to evaluate the effects of size mismatching. Regression analyses were performed to identify independent risk factors for surgical complications and graft survival, respectively. Perioperative surgical complications requiring revision were observed in 34 (15.4%) cases. Leading cause for revision were vascular complications such as thrombosis or stenosis (n = 15 [6.8%]), which were significantly more frequent in case of young donors, (ie, donor age <6 years; OR: 4.281; CI-95%:1.385-13.226; P = .012), previous nephrectomy (OR: 3.407; CI-95%:1.019-11.387; P = .046), and en-bloc grafts (OR: 4.923; CI-95%:1.355-17.884; P = .015), followed by postoperative hemorrhage (n = 10 [4.5%]), ureteral complications (n = 8 [3.6%]), and lymphoceles (n = 7 [3.2%]). Median follow-up was 84.13 (0.92-175.72) months. One-, 5-, and 10-year graft survival rates were 97.1%, 88.9%, and 65.1%, respectively. Except for vascular complications (HR: 4.727; CI-95%:1.363-16.394; P = .014), none of the analyzed surgical morbidities significantly influenced graft survival. In conclusion, pediatric kidney transplantation achieves excellent long-term results. However, meticulous surgical technique and continuous postoperative monitoring are imperative for early detection and treatment of imminent vascular complications, especially in case of young donors and en-bloc grafts.

Kidney transplantation with allografts from infant donors-Small organs, big value.

BACKGROUND: Although infant organ donors remain a rare source of organs for transplantation, technical challenges have resulted in increased rates of complications and inferior graft function. The aim of the present study was to investigate the outcomes of kidneys procured from juvenile and infant donors. PATIENTS AND METHODS: We evaluated all kidney transplants from deceased donors < 16 years of age performed at our center between 01/2008 and 08/2019. We defined three groups based on quartiles of donor body weight: <13 kg (infant donors), 13-40 kg (juvenile donors), and > 40 kg (standard criteria donors). Clinical characteristics and outcomes were compared between groups. RESULTS: Ninety-two transplants were included in this study. Out of 92 recipients, there were 32 (34.8%) adult and 60 (65.2%) pediatric patients. All groups demonstrated excellent graft function and survival on both short and long-term follow-up. 1-year, 3-year, and 5-year graft survival rates for the standard criteria donor group were 100%, 95.2%, and 88.4%, respectively, compared with 95.8% for infant and 95% for juvenile donors at all times (P = .79). eGFR at 5 years was 98.9 ± 5.5, 74.1 ± 6.2, and 81.6 ± 6.9 mL/min/1.73 m2 for infant, juvenile, and standard criteria donors, respectively (P < .01). CONCLUSION: Infant donor allografts can be transplanted with excellent long-term outcomes in both pediatric and adult recipients. Implanting them as single allografts onto pediatric candidates allows for the transplantation of two patients. As such, pediatric recipients should be prioritized for these donor organs.

Donor and recipient risk factor analysis of inferior postheart transplantation outcome in the era of durable mechanical assist devices.

The study objective is to quantify the impact of donor and recipient variables on heart transplant survival in recipients with a significant proportion of implanted continuous-flow left ventricular assist devices (LVADs). This is a prospective cohort study of International Society for Heart and Lung Transplantation (ISHLT) Registry that includes all primary heart-alone transplants in adult recipients (January 2005 and June 2013, N = 15 532, 27% LVADs). Donor and recipient characteristics were assessed for association with death or graft failure within 90 days and between 90 days and 5 years after transplantation. On Cox proportional hazard model donor cause of death other than head trauma (hazard ratio [HR] 1.985, P < 0.0001), recipient congenital (HR 2.7555, P < 0.0001) and ischemic (HR 1.165, P = 0.0383) vs dilated etiology and female donor heart transplanted into male recipient (HR 1.207, P = 0.0354) were predictors of death or graft failure within 90 days. Between 90 days and 5 years, donor cigarette use (HR 1.232, P = 0.0001), recipient cigarette use (HR 1.193, P = 0.0003), diabetes (HR 1.159, P = 0.0050), arterial hypertension (HR 1.129, P = 0.0115), and ischemic vs dilative cardiomyopathy had an increased probability of death or graft failure.

Anti-HLA sensitization in extensively burned patients: extent, associated factors, and reduction in potential access to vascularized composite allotransplantation.

Extensively burned patients receive iterative blood transfusions and skin allografts that often lead to HLA sensitization, and potentially impede access to vascularized composite allotransplantation (VCA). In this retrospective, single-center study, anti-HLA sensitization was measured by single-antigen-flow bead analysis in patients with deep, second- and third-degree burns over ≥40% total body surface area (TBSA). Association of HLA sensitization with blood transfusions, skin allografts, and pregnancies was analyzed by bivariate analysis. The eligibility for transplantation was assessed using calculated panel reactive antibodies (cPRA). Twenty-nine patients aged 32 ± 14 years, including 11 women, presented with a mean burned TBSA of 54 ± 11%. Fifteen patients received skin allografts, comprising those who received cryopreserved (n = 3) or glycerol-preserved (n = 7) allografts, or both (n = 5). An average 36 ± 13 packed red blood cell (PRBC) units were transfused per patient. In sera samples collected 38 ± 13 months after the burns, all patients except one presented with anti-HLA antibodies, of which 13 patients (45%) had complement-fixing antibodies. Eighteen patients (62%) were considered highly sensitized (cPRA≥85%). Cryopreserved, but not glycerol-preserved skin allografts, history of pregnancy, and number of PRBC units were associated with HLA sensitization. Extensively burned patients may become highly HLA sensitized during acute care and hence not qualify for VCA. Alternatives to skin allografts might help preserve their later access to VCA.

Predicted Heart Mass: A Tale of 2 Ventricles.

BACKGROUND: Total predicted heart mass (PHM) is the recommended metric to assess donor-recipient size matching in patients undergoing heart transplantation. Separately measuring right ventricular (RV) and left ventricular (LV) PHM may improve risk prediction of 1-year graft failure. METHODS: Adult heart transplant recipients from the UNOS database from 2000 to 2018 were included in the study. LV and RV PHM were modeled as restricted cubic splines. The association with 1-year graft failure was determined using adjusted Cox regression. The risk reclassification of using both LV and RV PHM versus total PHM was assessed using the net reclassification index. RESULTS: A total of 34 976 recipients were included. We observed a U-shaped association between total PHM and 1-year graft failure, such that risk increased for hearts undersized by >15% and those oversized by more than 27%. Graft failure incrementally increased when LV PHM was undersized by more than 5% and when RV was oversized by >20%. There was 1.5-fold greater risk of graft failure for an LV undersized by >26% or an RV oversized by more than 40%. Using LV and RV PHM risk-assessment separately led to a net reclassification index=8.5% ([95% CI, 5.3%-11.7%], nonevent net reclassification index=9.1%, event net reclassification index=-0.6%). CONCLUSIONS: The association between donor-recipient PHM match and the risk of graft failure after heart transplantation can be further understood as risk attributable to LV undersizing and RV oversizing. Assessing LV and RV PHM separately instead of total PHM could further refine the methods used to match donors and recipients for heart transplantation, minimize the risk of 1-year graft failure, and increase the use of donor organs.

A Matching Strategy To Guide Donor Selection for Ulcerative Colitis in Fecal Microbiota Transplantation: Meta-Analysis and Analytic Hierarchy Process.

Fecal microbiota transplantation (FMT) targeting gut microbiota has recently been applied to the treatment of ulcerative colitis (UC). However, preliminary trials showed that only a subset of patients responded to FMT, and the heterogeneity in donor gut microbiota probably played important roles in patients' responses, implying the significance of matching an appropriate donor to a specified patient. We developed a strategy to build a donor-recipient matching model to guide rational donor selection for UC in FMT. We collected and uniformly reanalyzed 656 fecal 16S rRNA gene sequencing samples (350 from UC patients and 306 from healthy subjects) from 9 studies. Significantly lower α-diversity indexes were observed in UC patients by random effects model. Thirty-four bacterial genera and 34 predicted pathways were identified with significant odds ratios and classification potentials for UC patients. Based on six bacterial indicators, including richness, overall distance, genera, and pathways (beneficial and harmful), the analytic hierarchy process-based donor-recipient matching model was set to rank and select appropriate donors for patients with UC. Finally, the model showed favorable classification powers (>70%) for FMT effectiveness in two previous clinical trials. This study revealed the dysbiosis of fecal bacterial diversity, composition, and predicted pathways of patients with UC by meta-analysis and hereby developed a donor-recipient matching strategy to guide donor selection for UC in FMT. This strategy can also be applied to other diseases associated with gut microbiota. IMPORTANCE Modulation of gut microbiota by FMT from donors has been applied to the treatment of UC and yielded variable effectiveness in clinical trials. One possibility is that this variable effectiveness was related to donor selection, as a patient's response to FMT may rely on the capability of the used donor's microbiota to restore the specific gut disturbances of the patient. However, the biggest issues on the practical level are what should be considered in the selection process and how to set up such a donor-recipient matching model. In this study, we presented a bacterial profile-based donor-recipient matching strategy to guide donor selection for UC in FMT by first meta-analysis of 656 fecal 16S rRNA gene sequencing samples from 9 studies to identify significant indicators and then setting up the model by an analytic hierarchy process. The applicability and accuracy of this model were verified in the data sets from two previous FMT clinical studies. Our data indicate that the donor-recipient matching model built in this study enables researchers to rationally select donors for UC patients in FMT clinical practice, although it needs more samples and prospective trials for validation. The strategy adopted in this study to leverage existing data sets to build donor-recipient matching models for precision FMT is feasible for other diseases associated with gut microbiota.

NephroCAGE-German-Canadian Consortium on AI for Improved Kidney Transplantation Outcome: Protocol for an Algorithm Development and Validation Study.

BACKGROUND: Recent advances in hardware and software enabled the use of artificial intelligence (AI) algorithms for analysis of complex data in a wide range of daily-life use cases. We aim to explore the benefits of applying AI to a specific use case in transplant nephrology: risk prediction for severe posttransplant events. For the first time, we combine multinational real-world transplant data, which require specific legal and technical protection measures. OBJECTIVE: The German-Canadian NephroCAGE consortium aims to develop and evaluate specific processes, software tools, and methods to (1) combine transplant data of more than 8000 cases over the past decades from leading transplant centers in Germany and Canada, (2) implement specific measures to protect sensitive transplant data, and (3) use multinational data as a foundation for developing high-quality prognostic AI models. METHODS: To protect sensitive transplant data addressing the first and second objectives, we aim to implement a decentralized NephroCAGE federated learning infrastructure upon a private blockchain. Our NephroCAGE federated learning infrastructure enables a switch of paradigms: instead of pooling sensitive data into a central database for analysis, it enables the transfer of clinical prediction models (CPMs) to clinical sites for local data analyses. Thus, sensitive transplant data reside protected in their original sites while the comparable small algorithms are exchanged instead. For our third objective, we will compare the performance of selected AI algorithms, for example, random forest and extreme gradient boosting, as foundation for CPMs to predict severe short- and long-term posttransplant risks, for example, graft failure or mortality. The CPMs will be trained on donor and recipient data from retrospective cohorts of kidney transplant patients. RESULTS: We have received initial funding for NephroCAGE in February 2021. All clinical partners have applied for and received ethics approval as of 2022. The process of exploration of clinical transplant database for variable extraction has started at all the centers in 2022. In total, 8120 patient records have been retrieved as of August 2023. The development and validation of CPMs is ongoing as of 2023. CONCLUSIONS: For the first time, we will (1) combine kidney transplant data from nephrology centers in Germany and Canada, (2) implement federated learning as a foundation to use such real-world transplant data as a basis for the training of CPMs in a privacy-preserving way, and (3) develop a learning software system to investigate population specifics, for example, to understand population heterogeneity, treatment specificities, and individual impact on selected posttransplant outcomes. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/48892.

Nondirected Living Kidney Donation and Recipient Outcomes in the United States: A 20-Year Review.

Introduction: Nondirected donation (NDD) of the kidneys is a growing practice where donors who do not have any genetic or emotional relationship are selected to donate to a wide variety of recipients with a range of selection criteria and decisions which are left up to individual transplant centers. Methods: We review all adult living kidney donor-recipient (DR) pairs and outcomes from NDDs who were recorded in United Network for Organ Sharing (UNOS) database as code 10 (anonymous) from October 1997 to September 2017 for demographics and outcomes. Results: A total of 2174 DR pairs were identified. The number of NDDs increased from 18 in 2000 to 256 in 2016. Survival analysis showed higher death-censored-graft survival (DC-GS) when recipient was 20 years or more older than donor followed by recipient-donor within 20 years of age and lowest when donor was 20 years or more older than recipient (P = 0.0114). Conclusion: Overall, the number of NDDs has increased significantly in the 20-year review period. Transplants from NDDs have excellent long-term outcomes. Better matching of controllable DR factors, such as age and body mass index (BMI), could further improve GS. Further research is needed to incorporate these DR factors into paired kidney donation programs potentially enhancing the utility and beneficence of this invaluable donation.

Ventricular assist device bridging with gender-mismatch increases rejection and decreases survival following a heart transplant.

OBJECTIVES: Survival is poor following an orthotopic heart transplant with gender-mismatched donors and recipients. Patients bridged to an orthotopic heart transplant with a ventricular assist device (VAD) frequently become sensitized. We hypothesized that the combination of VAD bridging and gender-mismatch may result in greater rejection and poorer survival. METHODS: Data were obtained from the United Network of Organ Sharing database. Patients were divided into 4 groups: (i) VAD recipients who received a heart from a gender-matched donor (VAD-M); (ii) VAD recipients who received a heart from a gender-mismatched donor (VAD-MM); (iii) noVAD recipients who received a heart from a gender-matched donor (noVAD-M); and (iv) noVAD recipients who received a heart from a gender-mismatched donor (noVAD-MM). Rejection episodes within 1-year post-transplant and transplant survival were compared in VAD-M versus VAD-MM and noVAD-M versus noVAD-MM groups, respectively. RESULTS: Between January 2000 and June 2017, of 33 401 adult patients who underwent heart transplants, 8648, 2441, 12 761 and 4992 patients were identified as VAD-M, VAD-MM, noVAD-M and noVAD-MM, respectively. Rejection within 1-year post-transplant occurred in 23.3% and 27.3% of the VAD-M and VAD-MM groups, respectively (P < 0.01) and in 21.8% and 23.6% of the noVAD-M and noVAD-MM groups (P = 0.02), respectively. In an adjusted survival analysis, the VAD-MM group showed significantly worse survival than the VAD-M group (P < 0.01), whereas there was no significant difference between the noVAD-M and noVAD-MM groups (P = 0.21). CONCLUSIONS: Our results indicated that the combination of VAD bridging and gender-mismatch caused greater rejection and worse survival following a transplant. Further study is necessary to prove comparable post-transplant survival of gender-matched or -mismatched recipients without VAD bridging.

Predicting the available space for liver transplantation in cirrhotic patients: a computed tomography-based volumetric study.

BACKGROUND: Anthropometric parameters (weight, height) are usually used for quick matching between two individuals (donor and recipient) in liver transplantation (LT). This study aimed to evaluate clinical factors influencing the overall available space for implanting a liver graft in cirrhotic patients. METHODS: In a cohort of 275 cirrhotic patients undergoing LT, we calculated the liver volume (LV), cavity volume (CV), which is considered the additional space between the liver and the right hypocondrium, and the overall volume (OV = LV + CV) using a computed tomography (CT)-based volumetric system. We then chose the formula based on anthropometric parameters that showed the best predictive value for LV. This formula was used to predict the OV in the same population. Factors influencing OV variations were identified by multivariable logistic analysis. RESULTS: The Hashimoto formula (961.3 × BSA_D-404.8) yielded the lowest median absolute percentage error (21.7%) in predicting the LV. The median LV was 1531 ml. One-hundred eighty-five patients (67.2%) had a median CV of 1156 ml (range: 70-7006), and the median OV was 2240 ml (range: 592-8537). Forty-nine patients (17%) had an OV lower than that predicted by the Hashimoto formula. Independent factors influencing the OV included the number of portosystemic shunts, right anteroposterior abdominal diameter, model for end-stage liver disease (MELD) score > 25, high albumin value, and BMI > 30. CONCLUSIONS: Additional anthropometric characteristics (right anteroposterior diameter, body mass index) clinical (number of portosystemic shunts), and biological (MELD, albumin) factors might influence the overall volume available for liver graft implantation. Knowledge of these factors might be helpful during the donor-recipient matching.

Evaluating twenty-years of follow-up after orthotopic liver transplantation, best practice for donor-recipient matching: What can we learn from the past era?

AIM: To characterize major determinants of 20-year survival after liver transplantation (LT). METHODS: This longitudinal single-institution study includes 313 consecutive patients who received a LT between 1988 and 1992. Pretransplant clinical characteristics and laboratory values were assessed and compared between 20-year survivors and non-survivors. Particular attention was paid to the Model for End-Stage Liver Disease (labMELD)-score and the Eurotransplant Donor Risk Index (ET-DRI) to unravel their impact on 20-year survival after LT. RESULTS: Twenty-year survivors were significantly younger (44 vs 50 years, P = 0.001), more likely to be female (49% vs 36%, P = 0.03) and less likely to be obese at the time of LT (19% vs 32%, P = 0.011). Mean labMELD-score (P = 0.156), rate of high-urgency LT (P = 0.210), cold-ischemia time (P = 0.994), rate of retransplantation (P = 0.12) and average donor age (28 vs 33 years, P = 0.099) were not statistically different. The mean estimated glomerular filtration rate was higher among survivors (P = 0.007). ET-DRI > 1.4 (P = 0.020) and donor age ≥ 30 years (P < 0.022) had significant influence on 20-year survival. The overall survival was not significantly impacted by labMELD-score categories (P = 0.263). CONCLUSION: LT offers excellent long-term results in case of optimal donor and recipient conditions. However, mainly due to the current organ shortage, these ideal circumstances are rarely given; thus algorithms for donor-recipient matching need to be refined, in order to enable a maximum benefit for the recipients of high quality as well as marginal organs.

D-MELD risk capping improves post-transplant and overall mortality under markov microsimulation.

AIM: To hypothesize that the product of calculated Model for End-Stage Liver Disease score excluding exception points and donor age (D-MELD) risk capping ± Rule 14 could improve post liver transplant and overall survival after listing. METHODS: Probabilities derived from the United Network for Organ Sharing database between 2002 and 2004 were used to simulate potential outcomes for all patients listed for transplantation. The Markov simulation was then modified by screening matches using a 1200 or 1600 D-MELD risk cap ± allowing transplants for Model for End-Stage Liver Disease (MELD) ≤ 14 (Rule 14). The differential impact of the rule changes was assessed. RESULTS: The Markov simulation accurately reproduced overall and post transplant survival. A 1200 D-MELD risk cap improved post-transplant survival. Both the 1200 and 1600 risk caps improved overall survival for waitlisted patients. The addition of Rule 14 further improved post transplant and overall survival by redistribution of donor livers to recipients in higher MELD subgroups. The mechanism for improved overall and post-transplant survival after listing was due to shifting a larger percentage of transplants to the moderate MELD score subgroup (MELD 15-29) while also ensuring that high MELD recipients have livers of high quality to achieve excellent post transplant survival. CONCLUSION: A 1200 D-MELD risk cap + Rule 14 provided the greatest overall benefit primarily by focusing liver transplantation towards the moderate MELD recipient.