Acceptance criteria of pancreas grafts: how do surgeons decide in Europe?

Outcome-Orientated Organ Allocation-A Composite Risk Model for Pancreas Graft Evaluation and Acceptance

Background: Pancreas transplantation (PTX) remains the most effective treatment to prevent long-term complications and provide consistent euglycemia in patients with endocrine pancreatic insufficiency, mainly in type I diabetic patients. Considering early graft loss (EGL) and the perioperative complication rate, an optimal risk stratification based on donor risk factors is paramount. Methods: In our single-center study, we retrospectively assessed the risk factors for EGL and reduced graft survival in 97 PTXs (82 simultaneous pancreas and kidney [SPK], 11 pancreases transplanted after kidney [PAK] and 4 pancreases transplanted alone [PTA]) between 2010 and 2021. By statistically analyzing the incorporation of different donor risk factors using the Kaplan-Meier method and a log-rank test, we introduced a composite risk model for the evaluation of offered pancreas grafts. Results: The overall EGL rate was 6.5%. In the univariate analysis of donor characteristics, age > 45 years, BMI > 25 kg/m2, lipase > 60 U/L, cerebrovascular accident (CVA) as the cause of death, mechanical cardiopulmonary resuscitation (mCPR), cold ischemia time (CIT) > 600 min and retrieval by another center were identified as potential risk factors; however, they lacked statistical significance. In a multivariate model, age > 45 years (HR 2.05, p = 0.355), BMI > 25 kg/m2 (HR 3.18, p = 0.051), lipase > 60 U/L (HR 2.32, p = 0.148), mCPR (HR 8.62, p < 0.0001) and CIT > 600 min (HR 1.89, p = 0.142) had the greatest impact on pancreas graft survival. We subsumed these factors in a composite risk model. The combination of three risk factors increased the rate of EGL significantly (p = 0.003). Comparing the pancreas graft survival curves for ≥3 risk factors to <3 risk factors in a Kaplan-Meier model revealed significant inferiority in the pancreas graft survival rate (p = 0.029). Conclusions: When evaluating a potential donor organ, grafts with a combination of three or more risk factors should only be accepted after careful consideration to reduce the risk of EGL and to significantly improve outcomes after PTX.

Solid pancreas transplant outcomes with increased donor and recipient ages compared to reference ages: A systematic review

BACKGROUND

Increased recipient and donor age are associated with worse solid organ pancreas transplant outcomes. However, donor and recipient age criteria vary between jurisdictions. We systematically reviewed studies reporting the association between transplanting older recipients and donors beyond current Transplantation Society of Australia and New Zealand (TSANZ) limits with solid pancreas transplant outcomes.

METHODS

Studies comparing transplant outcomes between a reference-age and an older-age donor (>45 years) or recipient (≥50 years) cohort for solid pancreas transplantation were included. Primary outcomes were pancreas/kidney graft and patient survival at one and five years. Secondary outcomes were post-transplant complications (graft thrombosis, acute rejection and relaparotomy rates).

RESULTS

11 studies were included (two studies assessing solid pancreas outcomes between older vs reference-aged donors and nine studies assessing outcomes between older vs reference-aged recipients). Seven of 11 studies were judged to be at high risk of bias. Primary and secondary outcomes were not significantly different between recipient age groups in nine studies. A sensitivity analysis of older vs reference-aged studies excluding studies at high risk of bias also showed non-inferior primary and secondary outcomes at one year. Two studies comparing outcomes by donor age showed worse graft survival but non-inferior patient survival with older donors.

CONCLUSION

Increased donor or recipient age alone should not absolutely contraindicate solid pancreas transplantation, especially if other risk predictors are minimised. This article is protected by copyright. All rights reserved.

Complications during multiorgan retrieval and pancreas preservation

In pancreas transplantation, complications can arise at each step of the process, from the initial selection of donors and recipients through the surgical technique itself and the post-operative period, when lifelong immunosuppression is required. In the early steps, careful retrieval and preservation of the pancreas are crucial for the viability of the organ and ultimate success of the transplant. The pancreas is a low-flow gland, making it highly sensitive to transplantation conditions and presenting risk of pancreatitis due to periods of ischemia. The two groups of donors - after brain death (DBD) or after cardiac arrest (DCD) - require different strategies of retrieval and preservation to avoid or reduce the risk of complications developing during and after the transplantation. For DBD donor transplantation, multiorgan retrieval and cold preservation is the conventional technique. Asystole donor (DCD) transplantation, in contrast, can benefit from the newest technologies, such as hypothermic and especially normothermic preservation machines (referred to as NECMO), to optimize organ preservation. The latter has led to an increase in the pool of donors by facilitating recuperation of organs for transplantation that would have been discarded otherwise.

Deceased Brain Dead Donor Liver Transplantation and Utilization in the United States: Nighttime and Weekend Effects

BACKGROUND

Understanding factors that contribute to liver discards and nonusage is urgently needed to improve organ utilization.

METHODS

Using Scientific Registry of Transplant Recipient data, we studied a national cohort of all US adult, deceased brain dead donor, isolated livers available for transplantation from 2003 to 2016, including organ-specific and system-wide factors that may affect organ procurement and discard rates.

RESULTS

Of 73 686 available livers, 65 316 (88.64%) were recovered for transplant, of which 6454 (9.88%) were ultimately discarded. Livers that were not procured or, on recovery, discarded were more frequently from older, heavier, hepatitis B virus (HCV)+, and more comorbid donors (P < 0.001). However, even after adjustment for organ quality, the odds of liver nonusage were 11% higher on the weekend (defined as donor procurements with cross-clamping occurring from 5:00 PM Friday until 11:59 AM Sunday) compared with weekdays (P < 0.001). Nonuse rates were also higher at night (P < 0.001), defined as donor procurements with cross-clamping occurring from 5:00 PM to 5:00 AM; however, weekend nights had significantly higher nonuse rates compared with weekday nights (P = 0.005). After Share 35, weekend nonusage rates decreased from 21.77% to 19.51% but were still higher than weekday nonusage rates (P = 0.065). Weekend liver nonusage was higher in all 11 United Network of Organ Sharing regions, with an absolute average of 2.00% fewer available livers being used on the weekend compared with weekdays.

CONCLUSIONS

Although unused livers frequently have unfavorable donor characteristics, there are also systemic and operational factors, including time of day and day of the week a liver becomes available, that impact the chance of liver nonprocurement and discard.

Maximizing Utilization in Pancreas Transplantation: Phenotypic Characteristics Differentiating Aggressive From Nonaggressive Transplant Centers

BACKGROUND

Maximizing pancreas utilization requires a balance between judicious donor selection and transplant center aggressiveness. We sought to determine how such aggressiveness affects transplant outcomes.

METHODS

Using the Scientific Registry of Transplant Recipients, we studied 28 487 deceased-donor adult pancreas transplants. Donor and recipient demographic factors indicative of aggressiveness were used to score center aggressiveness. We compared outcomes of low (> 1 SD below mean), medium (± 1 SD from mean), and high (> 1 SD above mean) aggressiveness centers using bivariate and multivariable regressions.

RESULTS

Donor and recipient aggressiveness demonstrated a roughly linear relationship (R = 0.20). Center volume correlated moderately with donor (rs = 0.433) and recipient (rs = 0.270) aggressiveness. In bivariate analysis, there was little impact of donor selection aggressiveness on graft survival. Further, for simultaneous pancreas and kidney transplants, centers with greater recipient aggressiveness selection had better graft survival. High-volume centers had better graft survival than low-volume centers. In multivariable analysis, donor aggressiveness did not have an effect on graft survival, whereas graft survival for medium (hazard ratio [HR], 0.66, 95% confidence interval [95% CI], 0.53-0.83) and high (HR, 0.67; CI, 0.51-0.86) recipient aggressiveness performed better than low-aggressiveness centers. There was a clear volume effect, with high-volume centers (>20 transplants/year; HR, 0.69; CI, 0.61-0.79) performing better than low-volume centers.

CONCLUSIONS

Center practice patterns using higher-risk donors and recipients did not negatively affect outcomes. This effect is likely mediated through efficiencies gained with the increased transplant volumes at these centers.

Pancreas donors

PURPOSE OF REVIEW

Donor issues have a direct impact on the pancreas transplant surgical procedure and play a critical role in the success of the procedure. The purpose of this review is to examine several key donor issues that are likely to have a significant impact on outcomes after pancreas transplant. This review will focus on recent publications dealing specifically with issues related to the pancreas donor.

RECENT FINDINGS

Overall pancreas donors remain underutilized, in the US and in Europe. Only about half of potential pancreas grafts are utilized at present. Concern over the quality of the organ, and the potential risk for surgical complications with extended criteria donor grafts is a major concern. Pancreas grafts from donation after cardiac death donors, for example, provide acceptable results in the long term, but may be associated with a higher incidence of early surgical problems. Risk factors for poor outcome can be identified with the donor that can help in better defining selection criteria, and may help to properly allocate pancreas grafts between whole organ versus islet cell transplantation.

SUMMARY

Proper donor selection and defining donor risk factors plays a critical role in pancreas graft allocation and ultimately the success of the operative procedure.

Validation of the Pancreatic Donor Risk Index in Simultaneous Pancreas-Kidney Transplantation Performed in Córdoba Hospital From 2000 to 2015

BACKGROUND

The Pancreatic Donor Risk Index (PDRI) was developed in 2010 in the United States to predict graft survival after pancreas transplantation, based on donor characteristics and logistical and technical conditions. The aim of the study was to validate the utility of PDRI as a pancreas allograft survival predictor in simultaneous pancreas-kidney transplantation (SPK) transplants performed in our hospital between 2000 and 2015.

METHODS

This retrospective analysis of 126 SPK transplants was performed by the same surgical team from the years 2000 to 2015. Donor variables that are integrated in the PDRI were calculated (age, sex, race, creatinine serum levels, body mass index, height, cold ischemia time, cause of death, type of pancreas transplant). Pancreatic graft survival at 1 and 5 years was calculated by use of the Kaplan-Meier test. Comparison of survival curves between PDRI risk quartiles was calculated by use of the log-rank test. Association between graft survival and variables integrating the PDRI was calculated by use of univariate Cox regression analysis.

RESULTS

Log-rank analysis found no statistically significant association between global graft survival and PDRI quartiles. Univariate Cox regression analysis showed a statistically significant association between graft survival and cold ischemia time (P < .05).

CONCLUSIONS

PDRI was not a useful tool to predict pancreatic graft outcomes in a Spanish reference population.

High alcohol intake in deceased donors has no effect on pancreas graft survival: a registry analysis

Outcomes of pancreas transplantation from donors with high alcohol consumption are poorly described. The UK Transplant Registry was used to determine whether donor alcohol intake influenced pancreas survival in simultaneous pancreas-kidney (SPK) transplants performed between 2006 and 2012 (n = 770). Recipients were stratified by donor alcohol intake: group I (n = 122)-high recent alcohol intake (>21 or >14 units of alcohol/week in males or females, respectively) or previous alcohol abuse and group II (n = 648)-low/unknown current intake and no previous alcohol abuse. Median current alcohol intake was higher in group I than group II: 36.3 vs. 10 units/week; P < 0.001. One- and five-year pancreas graft survivals were 88.5% and 73.6% in group I, and 87% and 74.9% in group II. There was no difference in unadjusted graft survival between groups I and II (P = 0.76), and no difference between group II and a subgroup of group I with a donor history of alcohol abuse and high current intake (P = 0.26), or from donors with current alcohol consumption of >50 units/week (P = 0.41). Pancreas donors with past alcohol abuse or current high intake are common, and graft outcomes appear to be acceptable. This analysis suggests that high donor alcohol intake, by itself, should not exclude consideration of pancreas transplantation.

Predictors of non-transplantation of adult donor organs--an observational study using routine data from Eurotransplant

BACKGROUND

The majority of pancreases, offered in allocation, are not transplanted. This pancreas under-utilisation is a phenomenon observed in all transplant systems in North-America and Europe. It was the aim of this study to analyse factors predictive of pancreas non-transplantation in Germany.

METHODS

Routine Eurotransplant data of 3,666 deceased German donors (from 2002-2011) were used for multivariate modelling. Socio-demographic and medical factors were considered as independent variables in logistic regression models with non-transplantation as dependent variable.

RESULTS

Male gender, advanced age, overweight/obesity, long ICU stay, a history of smoking, non-traumatic brain death, elevated levels of sodium, serum glucose, lipase/amylase and the liver not being considered for procurement were significant independent predictors of non-transplantation.

CONCLUSION

In line with previous research, advanced age, high BMI, long ICU stay and the liver not being considered for procurement were the strongest predictors of pancreas non-transplantation in Germany. About three quarters of the variance remained unexplained, suggesting that factors not assessed or unknown may play a decisive role.

Single-center experience using organs after rescue allocation for pancreas transplant in the eurotransplant region

OBJECTIVES

Because of the shortage of available organs for transplants, graft allocation polices have been modified recently. This report deals with the effect of using organs after rescue allocation for pancreas transplant in a single center in the Eurotransplant Region to possibly expand the donor pool.

MATERIALS AND METHODS

A retrospective analysis was performed. Between 2007 and 2010, thirty-one pancreas transplants were performed at the University Hospital of Leipzig, in Leipzig, Germany. Among these, 7 cases used rescue organs. These organs had been officially offered to, but rejected by, at least 3 consecutive transplant centers. Donor/recipient and clinical/laboratory transplant/posttransplant outcomes from patients receiving rescue organs were collected and were compared with organs from conventional donors.

RESULTS

Mean donor age was greater in the rescue organ group than in the conventional donor group (28.3 ± 10.7 y vs 23.0 ± 12.5 y). During follow-up (2.3 ± 0.6 y rescue organ group vs 3.9 ± 1.2 y conventional donor group), patient, kidney, and pancreas graft survival rates were 85% in all 3 categories in the rescue organ group, whereas outcomes for conventional donors were 88%, 85%, and 83%. Incidences of pancreatic graft thrombosis, delayed graft function, acute and late rejection episodes (eg, perioperative complications) were comparable between groups. No differences existed between mean serum urea levels and mean HbA1c levels between groups 2 years after transplant. Whereas 2 years after surgery, mean serum creatinine levels (rescue organ group, 78.8 ± 21.0 μmol/L vs 114.3 ± 28.4 μmol/L in the conventional donor group) showed significant differences between groups.

CONCLUSIONS

Results are promising. Further pro-spective studies are warranted to evaluate routine transplant of organs after rescue allocation.

Accept or refuse? Factors influencing the decision-making of transplant surgeons who are offered a pancreas: results of a qualitative study

Background

Most offered pancreases are not transplanted. This study investigates the factors that inform and influence the transplant surgeon’s decision to select an offered pancreas.

Methods

Semi-standardized interviews were conducted with 14 highly qualified transplant surgeons from all 14 German transplant centers performing > 5 pancreas transplantations per year. The interviews focused on medical and non-medical criteria on which the individual accept/refuse decision depends. Interviews were recorded, transcribed and underwent content analysis.

Results

The interviewees agreed upon certain main selection criteria, e.g. donor age, lab results, ICU stay. However, there was no consistency in judging these parameters, and clear cut-offs did not exist. The pancreas macroscopy is a pivotal factor, as well as knowing (and trusting) the donor surgeon. 3/14 surgeons reported that they had occasionally refused a pancreas because of staff shortage. Some interviewees followed a restrictive acceptance policy, whereas others preferred to accept almost any pancreas and inspect it personally before deciding.

Conclusion

The assessment of medical donor characteristics is highly inconsistent. Both very cautious as well as very permissive acceptance policies may render the allocation process less efficient. A more standardized policy should be discussed. Finally, better training for donor surgeons seems advisable, in order to increase trust and thus pancreas utilization.

Expanding the donor pool in pancreas transplantation

PURPOSE OF REVIEW

The current era of organ shortage has necessitated expansion of the currently available organ donor pool, to increase the number of pancreases available for transplant. This review summarizes the cumulative efforts of various centers in making this possible.

RECENT FINDINGS

Various centers are consistently reporting their experience with marginal donors; recent additions to the cohort have been increase in pancreases from donors after cardiac death (controlled and uncontrolled), update on long-term outcomes of live pancreas donors, as well as efforts at objectively assessing donor risk.

SUMMARY

It has become important for the transplanting surgeon to make difficult decisions on organ suitability and appropriateness depending upon the recipient's status. Further more, limiting further damage to these vulnerable grafts is important in improving utilization as well as successful transplantation.

Influence of donor- and recipient-specific factors on the postoperative course after combined pancreas-kidney transplantation

INTRODUCTION

Simultaneous pancreas-kidney (SPK) transplantation is state-of-the-art therapy for patients with type-1 diabetes mellitus and end-stage renal failure. Improvement of long-term organ function and long-term survival after transplantation is the main focus of current research, but improvement of the early postoperative course is very important for the patient. Pancreas transplantation is associated with postoperative complications. We defined and identified donor- and recipient-specific factors related to postoperative complications.

PATIENTS AND METHODS

We carried out 210 SPKs from April 1995 to December 2007. The early postoperative course until first discharge from hospital was analyzed. Complications (pancreas-specific and surgical) were revisited. Donor-specific factors such as sex, age, body mass index (BMI), laboratory values, catecholamine administration, time in the intensive care unit, preprocurement blood substitution, and asystolic periods, as well as factors related to the organ donation procedure, were assessed. Recipient-specific factors such as age, sex, BMI, and blood group were correlated with the prevalence of complications and postoperative outcome. Donor-specific risk factors correlating with postoperative complications included donor age, BMI, and blood transfusion in the donor before organ donation.

RESULTS

Graft preservation with histidine-tryptophan-ketoglutarate perfusion solution was related to a significantly higher number of surgical complications.When analyzing recipient-specific factors, pre-existing cardiac diseases influenced the prevalence of postoperative complications. The duration of the transplantation procedure was associated with significantly more complications. The anastomosis time was not significantly related to an increased prevalence of complications. The choice of immunosuppression had a significant effect on pancreas-specific complications, demonstrating that antithymocyte globulin instead of daclizumab had a negative effect. Initial immunosuppression with tacrolimus combined with mycophenolate mofetil (MMF) caused significantly fewer pancreas-related complications in comparison with tacrolimus combined with rapamycin as well as compared with cyclosporine combined with MMF. A high level of C-reactive protein within the first 7 days after transplantation was significantly related to an increased prevalence of complications.

CONCLUSIONS

Early postoperative complications after combined pancreas-kidney transplantation have a considerable effect on short- and long-term outcomes. Several statistically relevant factors related to pancreas- or surgery-associated complications could be identified. These data may help to improve early outcome after SPK by consideration of relevant risk factors when choosing an organ and a recipient for transplantation.