Optimizing the program-specific reporting of pancreas transplant outcomes

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.

Risk indices predicting graft use, graft and patient survival in solid pancreas transplantation: a systematic review

BACKGROUND

Risk indices such as the pancreas donor risk index (PDRI) and pre-procurement pancreas allocation suitability score (P-PASS) are utilised in solid pancreas transplantation however no review has compared all derived and validated indices in this field. We systematically reviewed all risk indices in solid pancreas transplantation to compare their predictive ability for transplant outcomes.

METHODS

Medline Plus, Embase and the Cochrane Library were searched for studies deriving and externally validating risk indices in solid pancreas transplantation for the outcomes of pancreas and patient survival and donor pancreas acceptance for transplantation. Results were analysed descriptively due to limited reporting of discrimination and calibration metrics required to assess model performance.

RESULTS

From 25 included studies, discrimination and calibration metrics were only reported in 88% and 38% of derivation studies (n = 8) and in 25% and 25% of external validation studies (n = 12) respectively. 21 risk indices were derived with mild to moderate ability to predict risk (C-statistics 0.52-0.78). Donor age, donor body mass index (BMI) and donor gender were the commonest covariates within derived risk indices. Only PDRI and P-PASS were subsequently externally validated, with variable association with post-transplant outcomes. P-PASS was not associated with pancreas graft survival.

CONCLUSION

Most of the risk indices derived for use in solid pancreas transplantation were not externally validated (90%). PDRI and P-PASS are the only risk indices externally validated for solid pancreas transplantation, and when validated without reclassification measures, are associated with 1-year pancreas graft survival and donor pancreas acceptance respectively. Future risk indices incorporating recipient and other covariates alongside donor risk factors may have improved predictive ability for solid pancreas transplant outcomes.

Development and results of a novel pancreas transplant program in Spain: the surgeon's point of view

INTRODUCTION

Simultaneous kidney-pancreas transplantation for patients with type 1 diabetes and end-stage chronic renal disease is widely performed. However, the rate of surgical morbidity from pancreatic complications remains high. The aim of this study was to describe the development and results of a new program, from the point of view of the pancreatic surgeon.

METHODS

We analyzed 53 simultaneous kidney-pancreas transplantations performed over a period of seven years (2009-2016), with a median follow up of 39 months (range: 1-86 months).

RESULTS

Out of the total of this series, two patients died: one patient because of cardiac arrest immediately after surgery; and another patient due to traffic accident, complicated by pneumonia. Among the 51 living patients, two grafts were lost: one due to chronic rejection four years after transplantation; and the other due to arterial thrombosis 20 days after transplantation (the only case requiring transplantectomy). In ten patients, one or more re-operations were necessary due to the following: graft pancreatitis (n=4), small intestinal obstruction (n=4), arterial thrombosis (n=1), fistula (n=1) and hemoperitoneum (n=1). Overall patient and graft survival rates after 1, 3 and 5 years were 98, 95 and 95% and 96, 93 and 89%, respectively.

CONCLUSIONS

This study has shown that the results of a new pancreas transplant program, which relies on the previous experience of other groups, do not demonstrate a learning curve. Adequate surgeon education and training, as well as the proper use of standardized techniques, should ensure optimal results.

A Single-center Experience on the Value of Pancreas Graft Biopsies and HLA Antibody Monitoring After Simultaneous Pancreas-Kidney Transplantation

BACKGROUND

In simultaneous pancreas-kidney transplantation (SPKT), monitoring of the pancreas allograft is more complex than the kidney allograft due to difficulties in obtaining pancreas histology and weak clinical evidence supporting the role of donor-specific antibodies (DSA).

METHODS

We performed a single-center retrospective analysis of all 17 SPKT recipients who underwent a total of 22 pancreas allograft indication biopsies from October 2009 to September 2012. Fifteen patients had at least 2 DSA measurements: pretransplantation and at the time of biopsy.

RESULTS

All 7 patients (100%) with post-transplantation DSA-positivity (de novo: n = 6; persistent: n = 1) at biopsy had at least 1 rejection episode either of the pancreas (n = 4) or the kidney (n = 3), with 3 antibody-mediated rejections (AMR). In contrast, only 4 of 8 patients (50%) without post-transplantation DSA had evidence of rejection, with 1 AMR. Findings during pancreas allograft biopsy procedures led to a change of immunosuppressive therapy in 11 of 15 (73%) patients. Patient survival, graft survival, and function were not adversely affected by the presence of post-transplantation DSA. One major and 2 minor procedure-related complications occurred during the pancreas biopsies.

CONCLUSIONS

In this small retrospective analysis, pancreas allograft histology provided the most therapeutically relevant information, rather than the kidney histology or DSA monitoring.

Current state of clinical end-points assessment in transplant: Key points

Solid organ transplantation is the treatment of choice for patients with end-stage organ disease. However, organ transplantation can stress the cardiovascular system and decrease immune surveillance, leading to early mortality and graft loss due to multiple underlying comorbidities. Clinical end-points in transplant include death and graft failure. Thus, generating accurate predictive models through regression models is crucial to test for definitive clinical post-transplantation end-points. Survival predictive models should assemble efficient surrogate markers or prognostic factors to generate a minimal set of variables derived from a proper modeling strategy through regression models. However, a few critical points should be considered when reporting survival analyses and regression models to achieve proper discrimination and calibration of the predictive models. Additionally, population-based risk scores may underestimate risk prediction in transplant. The application of predictive models in these patients should therefore incorporate both classical and non-classical risk factors, as well as community-based health indicators and transplant-specific factors to quantify the outcomes in terms of survival properly. This review focuses on assessment of clinical end-points in transplant through regression models by combining predictive and surrogate variables, and considering key points in these analyses to accurately predict definitive end-points, which could aid clinicians in decision making.

Thirty Years of Pancreas Transplantation at Leiden University Medical Center: Long-term Follow-up in a Large Eurotransplant Center

BACKGROUND

An overview of 30 years of pancreas transplantation at a high volume center. Analysis of patient survival- and graft survival-associated risk factors.

METHODS

All pancreas transplantations performed in our center from January 1, 1984, till December 31, 2012, were evaluated. Covariates influencing pancreas graft survival were analyzed using both univariate and multivariate analysis and Kaplan-Meier analysis.

RESULTS

In the study period, 349 pancreas transplantations were performed. With the introduction of modern induction therapy in 1999, 5-year patient survival improved to 92.0% (P = 0.003). Five-year pancreas graft survival improved to 80.3% (P = 0.026). Pancreas graft survival was influenced by left or right donor kidney, transplant type, local origin of procurement team, pancreas cold ischemia time, recipient cerebrovascular disease. Pancreas donor risk index increased to 1.39 over the years and pancreas donor risk index 1.24 or higher is a risk factor for graft survival (P = 0.007).

CONCLUSIONS

This study has shown excellent results in patient and pancreas graft survivals after 30 years of pancreas transplantation in a high volume center. Different donor, transplant, and recipient related risk factors influence pancreas graft survival. Even with higher risk pancreas donors, good results can be achieved.

Kidney transplant options for the diabetic patient

For patients with diabetes and progressive chronic kidney disease, kidney transplantation is the optimal mode of renal replacement therapy, with or without a pancreas transplant. Additional benefits of pancreas transplant have become increasingly apparent due to advances in surgical outcomes and immunosuppression, and may be reasonably considered even in selected patients with type 2 diabetes. In general, pancreas transplantation is associated with long-term survival advantages despite an increased short-term morbidity and mortality risk. This is true with simultaneous pancreas kidney transplantation or pancreas after kidney transplantation compared to kidney transplantation alone, regardless of kidney donor status (living or deceased). Individual patient preferences, comorbidities, and expected waiting time influence selection of transplant modality, rather than a clear survival benefit of one strategy versus the other. In selected patients with type 2 diabetes, recent outcomes data support cautious utilization of simultaneous pancreas kidney transplantation when a living kidney donor transplant is not an option. The purpose of this review is to summarize current data regarding kidney and pancreas transplant treatment options in patients with both type 1 and 2 diabetes and the influence of current organ allocation policies to better understand the advantages and disadvantages of each of these strategies.