Multivariate analysis of donor risk factors for pancreas allograft failure after simultaneous pancreas-kidney transplantation

Association of Procurement Time With Pancreas Transplant Outcomes in Brain-Dead Donors

A brain-death-induced cytokine storm damages organs in an organ donor. However, a longer time period between declaration of brain death and organ procurement (procurement interval) is associated with improved outcomes in kidney, liver, heart, and lung transplantation. The aim of this study was to find the optimal procurement interval for pancreas transplantation. Association of procurement interval with pancreas graft outcomes was analyzed using multivariable models adjusted for variables possibly affecting procurement interval and outcomes. Altogether 10,119 pancreas transplantations were included from the Scientific Registry of Transplant Recipients. The median follow-up was 3.2 (IQR 1.01-6.50) years. During the first year, 832 (9.0%) grafts were lost, including 555 (6.0%) within the first 30 days. Longer procurement interval was associated with increased death-censored graft survival in a multivariable model (HR 0.944 95% CI 0.917-0.972, per 10-h increase, p < 0.001). A decreasing hazard of graft loss was observed also with 1-year, but not with 30-day graft survival. During 1-year follow-up, 953 (12.1%) patients had an acute rejection, and longer procurement interval was also associated with less acute rejections (OR 0.937 95% CI 0.900-0.976, per 10-h increase, p = 0.002) in the multivariable model. In conclusion, longer procurement interval is associated with improved long-term outcomes in pancreas transplantation.

Risk Factors for Early Pancreatic Allograft Thrombosis Following Simultaneous Pancreas-Kidney Transplantation: A Systematic Review

Simultaneous pancreas-kidney (SPK) transplantation remains the most effective treatment for providing consistent and long-term euglycemia in patients having type 1 diabetes with renal failure. Thrombosis of the pancreatic vasculature continues to contribute significantly to early graft failure and loss. We compared the rate of thrombosis to graft loss and systematically reviewed risk factors impacting early thrombosis of the pancreas allograft following SPK transplantation. We searched the MEDLINE, EMBASE, The Cochrane Library, and PREMEDLINE databases for studies reporting thrombosis following pancreas transplantation. Identified publications were screened for inclusion and synthesized into a data extraction sheet. Sixty-three studies satisfied eligibility criteria: 39 cohort studies, 22 conference abstracts, and 2 meta-analyses. Newcastle-Ottawa Scale appraisal of included studies demonstrated cohort studies of low bias risk; 1127 thrombi were identified in 15 936 deceased donor, whole pancreas transplants, conferring a 7.07% overall thrombosis rate. Thrombosis resulted in pancreatic allograft loss in 83.3% of reported cases. This review has established significant associations between donor and recipient characteristics, procurement and preservation methodology, transplantation technique, postoperative management, and increased risk of early thrombosis in the pancreas allograft. Further studies examining the type of organ preservation fluid, prophylactic heparin protocol, and exocrine drainage method and early thrombosis should also be performed.

Donor risk factors in pancreas transplantation

The aim of the work was to analyze and expose the donor and recipient risk factors in pancreas transplantation. In the following paper, we exposed the 2018 Spanish Consensus Document on Donor and Recipient Selection Criteria for Pancreas Transplantation. An assessment of the previous Selection Criteria for Donors and Recipients of Pancreas Transplantation, published in 2005 by the Spanish Pancreas Transplant Group (GETP) and the National Transplant Organization (ONT) was performed. A literature review was performed using Cochrane Library, PubMed and Google Scholar databases. Some of the following terms were used for the literature search: “Diabetes Mellitus,” “Pancreas Transplantation,” “Insulin-Secreting Cells,” “Pancreas Allograft Thrombosis,” “Allograft Pancreatitis,” “Donors’ Risk Factors,” “Recipients’ Risk Factors,” “Pancreas Allograft Rejection” and “Pancreas Allograft Survival.” After an extended search, different inclusion criteria were established. Articles and documents with abstracts of full text and in English or Spanish language were selected. Subsequently, different scientific meetings took place during 2015 and 2016 by the GETP. Finally, the updated criteria were published by the GETP and ONT in 2018. Several risk factors have been described in pancreas transplantation that can be divided into donor risk factors: Advanced age (> 50 years); high body mass index (BMI) (> 30 kg/m²); cause of death (e.g., stroke); previous hyperglycemia; hyperamylasemia; cold ischemia time (greater than 8 or 12 h, depending on the type of donation); the use of vasopressors in the intensive care unit or cardiac arrest; and the macroscopic aspect of the pancreas allograft. The following are recipient risk factors: Advanced age (> 50 years); active smoking; high BMI (> 30 kg/m²); and peripheral artery disease or sensorimotor polyneuropathy. Based on the aforementioned parameters, different selection criteria have been established for the recipients depending on the type of pancreas transplantation. Knowledge of the risk factors for pancreas transplantation allows the establishment of reliable selection criteria for choosing donors and recipients.

Impact of an older donor pancreas on the outcome of pancreas transplantation: single-center experience of the expansion of donor criteria

PURPOSE

The impact of using an older donor pancreas on the clinical outcomes of pancreas transplantation (PTx) is unknown. We investigated this by comparing the outcomes of PTx using older and younger donors in a single Japanese center, to expand the donor criteria.

METHODS

The subjects were 54 patients who received PTx from deceased donors in our institution. Posttransplant outcomes were analyzed based on donor age, with older donors defined as those aged ≥ 60 years.

RESULTS

The donors included six older (11.1%; aged 64 ± 4 years) and 48 younger donors (88.9%; aged 43 ± 12 years). There was no significant difference in the donor age between the recipients with vs. those without postoperative complications or between those with vs. those without early pancreas graft loss. Long-term outcomes, including overall, pancreas graft, and kidney graft survival after PTx, did not differ significantly between the older and younger donor groups. Graft age, defined as the age of the donor at the time of procurement plus the graft survival period, was not associated with graft loss.

CONCLUSION

Our results suggest that post-transplant outcomes of PTx using pancreas from older donors aged ≥ 60 years are comparable to those using pancreas from younger donors, and support expansion of the donor pool for transplantation therapy for type 1 diabetes mellitus.

Outcomes of pancreas retransplantation in patients with pancreas graft failure

Background

Pancreas retransplantation is still a controversial option after loss of a pancreatic graft. This article describes the experience of pancreas retransplantation at a high‐volume centre.

Methods

This was a retrospective observational study of all pancreas retransplantations performed in a single centre between 1997 and 2013. Pancreatic graft loss was defined by the return to insulin dependence. Risk factors for graft loss as well as patient and graft survival were analysed using logistic and time‐to‐event regression models.

Results

Of 409 pancreas transplantations undertaken, 52 (12·7 per cent) were identified as pancreas retransplantations. After a median follow‐up of 65·0 (range 0·8–174·3) months, 1‐ and 5‐year graft survival rates were 79 and 69 per cent respectively, and 1‐ and 5‐year patient survival rates were 96 and 89 per cent. During the entire follow‐up, 22 grafts (42 per cent) were lost. Patient survival was not associated with any of the donor‐ or recipient‐related factors investigated. Five‐year graft survival was better after simultaneous kidney–pancreas retransplantation than pancreas retransplantation alone: 80 per cent (16 of 20) versus 63 per cent (20 of 32) (P = 0·226). Acute rejection (odds ratio 4·49, 95 per cent c.i. 1·59 to 12·68; P = 0·005) and early surgical complications (OR 3·29, 1·09 to 9·99, P = 0·035) were identified as factors with an independent negative effect on graft survival.

Conclusion

Pancreas retransplantation may be considered for patients whose previous graft has failed.

Good outcome in selected patients

Links between a biomarker profile, cold ischaemic time and clinical outcome following simultaneous pancreas and kidney transplantation

In sepsis, trauma and major surgery, where an explicit physiological insult leads to a significant systemic inflammatory response, the acute evolution of biomarkers have been delineated. In these settings, Interleukin (IL) -6 and TNF-α are often the first pro-inflammatory markers to rise, stimulating production of acute phase proteins followed by peaks in anti-inflammatory markers. Patients undergoing SPKT as a result of diabetic complications already have an inflammatory phenotype as a result of uraemia and glycaemia. How this inflammatory response is affected further by the trauma of major transplant surgery and how this may impact on graft survival is unknown, despite the recognised pro-inflammatory cytokines' detrimental effects on islet cell function. The aim of the study was to determine the evolution of biomarkers in omentum and serum in the peri-operative period following SPKT. The biochemical findings were correlated to clinical outcomes. Two omental biopsies were taken (at the beginning and end of surgery) and measured for CD68+ and CD206+ antibodies (M1 and M2 macrophages respectively). Serum was measured within the first 72 h post-SPKT for pro- and anti-inflammatory cytokines (IL -6, -10 and TNF-α), inflammatory markers (WCC and CRP) and endocrine markers (insulin, C-peptide, glucagon and resistin). 46 patients were recruited to the study. Levels of M1 (CD68+) and M2 (CD206+) macrophages were significantly raised at the end of surgery compared to the beginning (p = 0.003 and p < 0.001 respectively). Levels of C-peptide, insulin and glucagon were significantly raised 30 min post pancreas perfusion compared to baseline and were also significantly negatively related to prolonged cold ischaemic time (CIT) (p < 0.05). CRP levels correlated significantly with the Post-Operative Morbidity Survey (p < 0.05). The temporal inflammatory marker signature after SPKT is comparable to the pattern observed following other physiological insults. Unique to this study, we find that CIT is significantly related to early pancreatic endocrine function. In addition, this study suggests a predictive value of CRP in peri-operative morbidity following SPKT.

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.

Predictors of 10-year pancreas allograft survival after simultaneous pancreas and kidney transplantation

OBJECTIVE

This study aimed to identify the preoperative, perioperative, and postoperative factors affecting 10-year pancreas allograft survival after simultaneous pancreas and kidney (SPK) transplantation.

METHODS

Analysis was performed on a prospectively maintained database of 56 SPK transplants consecutively performed between January 1992 and October 2002. The definition cutoff points of specific variables were obtained by the receiver operating characteristic curve and multiple logistic regression analyses that were performed to determine the predictors of pancreas allograft survival after 10 years.

RESULTS

In total, 44 (79%) patients had an overall survival of more than 10 years, and the overall 10-year pancreas allograft survival rate was 57% (n = 32/56). The significant predictors for pancreas allograft failure in 10 years and above were kidney allograft failure (P = 0.04), serum creatinine 1 year postoperatively (P = 0.002), and serum hemoglobin A1c (HbA1c) level 2 years postoperatively (P = 0.003). A serum creatinine cutoff value of more than 129 μmol/L at 1 year was 87.5% sensitive and 70% specific for predicting pancreas allograft failure at 10 years. Serum HbA1c of more than 5.6% at 2 years was 85.7% sensitive and 62.5% specific for predicting pancreas allograft failure at 10 years. On multivariate analysis, 129 μmol/L and above of serum creatinine and more than 5.6% of serum HbA1c were the independent predictors of pancreas allograft failure at 10 years.

CONCLUSIONS

These findings may provide important information for identifying patients at risk for long-term pancreas allograft failure after SPK transplantation.

The allocation of pancreas allografts on donor age and duration of intensive care unit stay: the experience of the North Italy Transplant program

Starting in 2011, the North Italy Transplant program (NITp) has based on the allocation of pancreas allografts on donor age and duration of intensive care unit (ICU) stay, but not on donor weight or BMI. We analyzed the detailed allocation protocols of all NITp pancreas donors (2011-2012; n = 433). Outcome measures included donor characteristics and pancreas loss reasons during the allocation process. Twenty-three percent of the 433 pancreases offered for allocation were transplanted. Younger age, shorter ICU stay, traumatic brain death, and higher eGFR were predictors of pancreas transplant, either as vascularized organ or as islets. Among pancreas allografts offered to vascularized organ programs, 35% were indeed transplanted, and younger donor age was the only predictor of transplant. The most common reasons for pancreas withdrawal from the allocation process were donor-related factors. Among pancreas offered to islet programs, 48% were processed, but only 14.2% were indeed transplanted, with unsuccessful isolation being the most common reason for pancreas loss. Younger donor age and higher BMI were predictors of islet allograft transplant. The current allocation strategy has allowed an equal distribution of pancreas allografts between programs for either vascularized organ or islet transplant. The high rate of discarded organs remained an unresolved issue.

Outcomes and survival analysis of old-to-old simultaneous pancreas and kidney transplantation

Outcomes of old-donor simultaneous pancreas-kidney transplantation (SPKT) have not been thoroughly studied. Scientific Registry of Transplant Recipients data reported for SPKT candidates receiving dialysis wait-listed between 1993 and 2008 (n = 7937) were analyzed for outcomes among those who remained listed (n = 3301) and of SPKT recipients (n = 4636) using multivariable time-dependent regression models. Recipients were stratified by donor/recipient age (cutoff 40 years) into: young-to-young (n = 2099), young-to-old (n = 1873), old-to-young (n = 293), and old-to-old (n = 371). The overall mortality was 12%, 14%, 20%, and 24%, respectively, for those transplanted, and 50% for those remaining on the waiting list. On multivariable analysis, old-donor SPKT was associated with significantly higher overall risks of patient death, death-censored pancreas, and kidney graft failure in both young (73%, 53%, and 63% increased risk, respectively) and old (91%, 124%, and 85% increased risk, respectively) recipients. The adjusted relative mortality risk was similar for recipients of old-donor SPKT compared with wait-listed patients including those who subsequently received young-donor transplants (aHR 0.95; 95% CI 0.78, 1.12) except for candidates in OPOs with waiting times ≥604 days (aHR 0.65, 95% CI 0.45-0.94). Old-donor SPKT results in significantly worse graft survival and patient mortality without any waiting-time benefit as compared to young-donor SPKT, except for candidates with expected long waiting times.

Early pancreas allograft thrombosis

OBJECTIVES

To determine factors associated with early pancreatic allograft thrombosis (EPAT). Thrombosis is the leading non-immunological cause of early pancreatic allograft failure. Multiple risk factors have been postulated. We hypothesized that recipient perioperative hypotension was a major risk factor and evaluated the correlation of this and other parameters with EPAT.

METHODS

We retrospectively reviewed the records of the 118 patients who received a pancreatic allograft at our center between October 1992 and January 2010. Multiple donor and recipient parameters were analyzed as associates of EPAT by univariate and multivariate analysis.

RESULTS

There were 12 episodes of EPAT, resulting in an incidence of 10.2%. On univariate analysis, EPAT was associated with perioperative hypotension, vasopressor use, and neuropathy in the recipient (p ≤ 0.04 for all). On multivariate analysis corrected for age, sex, and peripheral vascular disease, only vasopressor use retained a significant association with EPAT with a hazard ratio of 8.74 (CI 1.11-68.9, p = 0.04). Factors associated with vasopressor use included recipient ischemic heart disease, peripheral vascular disease, retinopathy or neuropathy, and any surgical complication.

CONCLUSIONS

Significant hypotension, measured by the need for perioperative vasopressor use was associated with EPAT, suggesting that maintenance of higher perfusion pressures may avoid this complication.

Outcomes of extended donors in pancreatic transplantation with portal-enteric drainage

OBJECTIVE

Limited data are available on extended (EX) donor criteria in pancreatic transplantation (PTX).

METHODS

This retrospective study from February 2007 through April 2007 compared 2 cohorts of simultaneous kidney-pancreas transplantations (SKPT): the first from EX donors, which were defined as age <10 years or > or =45 years, or donation after cardiac death [DCD]), and the second from conventional (CONV) donors.

RESULTS

Among 79 SKPT, 19 (24%) were from EX donors (12 older than age 45 [mean age, 50.2 years], 3 pediatric donors <10, and 4 DCD donors) and the remaining 60 SKPT from CONV donors. The mean donor age was higher in EX than CONV donors (38 vs 25 years, P < .05). There were no other differences between the 2 cohorts. With a similar median follow-up of 29 months, patient, kidney and pancreatic graft survival rates were 89%, 89%, and 79%, for the EX, whereas corresponding outcomes for CONV donors were 93%, 87%, and 80%, respectively (all P = NS). The incidences were similar for delayed kidney graft function (5% in each group), early pancreatic graft loss due to thrombosis (5% EX vs 8% CONV donors), acute rejection (16% EX vs 18% CONV donors), surgical complications, and infections. There were no significant differences in 1-year mean serum creatinine (1.4 mg/dL in each group) or glycohemoglobin (5.2% vs 5.5%) levels between the EX and CONV donor groups, respectively.

CONCLUSION

Short-term outcomes among SKPT from selected EX donors were comparable to CONV donors. Donors at the extremes of age and DCD donors may represent underused resources in SKPT.

Perspectives in organ preservation

Maintaining organ viability after donation until transplantation is critically important for optimal graft function and survival. To date, static cold storage is the most widely used form of preservation in every day clinical practice. Although simple and effective, it is questionable whether this method is able to prevent deterioration of organ quality in the present era with increasing numbers of organs retrieved from older, more marginal, and even non-heart-beating donors. This review describes principles involved in effective preservation and focuses on some basic components and methods of abdominal organ preservation in clinical and experimental transplantation. Concepts and developments to reduce ischemia related injury are discussed, including hypothermic machine perfusion. Despite the fact that hypothermic machine perfusion might be superior to static cold storage preservation, organs are still exposed to hypothermia induced damage. Therefore, recently some groups have pointed at the beneficial effects of normothermic machine perfusion as a new perspective in organ preservation and transplantation.

Organ donation and utilization, 1995-2004: entering the collaborative era

Continued progress in organ donation will help enable transplantation to alleviate the increasing incidence of end-stage organ disease. This article discusses the implementation and effect of the federally initiated Organ Donation Breakthrough Collaborative; it then reviews organ donation data, living and deceased, from 1995 to 2004. It is the first annual report of the Scientific Registry of Transplant Recipients to include national data following initiation of the collaborative in 2003. Prior to that, annual growth in deceased donation was 2%-4%; in 2004, after initiation of the collaborative, deceased donation increased 11%. Identification and dissemination of best practices for organ donation have emphasized new strategies for improved consent, including revised approaches to minority participation, timing of requests and team design. The number of organs recovered from donation after cardiac death (DCD) grew from 64 in 1995 to 391 in 2004. While efforts are ongoing to develop methodologies for identifying expanded criteria donors (ECD) for organs other than kidney, it is clear DCD and ECD raise questions regarding cost and recovery. The number of living donor organs increased from 3493 in 1995 to 7002 in 2004; data show trends toward more living unrelated donors and those providing non-directed donations.

Successful simultaneous kidney-pancreas transplantation from extreme donors

The purpose of this study was to retrospectively review our experience with "extreme" pancreas donors compared to conventional (CONV) donors.

METHODS

"Extreme" (EX) pancreas donors were defined as deceased donors (DDs) age >50 years, <8 years, donation after cardiac death (DCD), and targeted for organ discard.

RESULTS

From January 2002 through January 2005, we performed 40 simultaneous kidney-pancreas transplants (SKPT) with Thymoglobulin induction, including 9 (22.5%) from EX and 31 from CONV DDs. Mean DD age was higher in EX DD (41.2 years EX vs 26.0 CONV, P < .05), but mean recipient age and cold ischemia times did not differ between groups. With a mean follow-up of 16.8 months in the EX DD group, patient and kidney graft survival rates are both 100%, and the pancreas graft survival rate is 89%. With a mean follow-up of 21.7 months in the CONV DD group, patient and kidney graft survival rates are both 93.5% and the pancreas graft survival rate is 77.4%. All patients with surviving grafts exhibited good initial (1 case of delayed kidney graft function in a CONV DD) and stable long-term kidney and pancreas graft function. Mean length of initial hospital stay and the incidences of acute rejection, readmissions, operative complications, and infections were similar between groups.

CONCLUSIONS

The results of this study suggest that the limits of donor acceptability continue to evolve as excellent outcomes can be achieved in SKPTs from selected EX DDs.

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

OBJECTIVES

Some donor factors, such as age, cause of death, and obesity, affect the outcomes of pancreas transplantation. Donors with a high-risk profile are usually not declined for pancreas donation. The purpose of our study was to investigate differences between accepted and refused pancreata after being procured and offered.

METHODS

In a retrospective study we analyzed all offered pancreata (n = 1360) in the "Eurotransplant Area" between May 25, 2002 and September 18, 2003. Included in this study were 525 pancreata transplanted (38.6%) and 608 pancreata refused for medical reasons (44.7%). A total of 227 pancreata (16.7%) refused for other than medical reasons were excluded from this analysis.

RESULTS

The significant differences in the donor profiles between transplanted and refused pancreata were cause of death (P < .001), donor age (P < .001), body mass index (BMI, P < .001), serum lipase and amylase (P < .05) at the time of procurement, and a history of smoking (P = .001) or alcohol abuse (P < .001). No differences were found for serum sodium (P = .188), blood leukocytes (P = .349), serum glucose at the time of procurement (P = .155), amylase and lipase at the time of admission (P = .34; P = .758), and vasopressor use at the time of admission or at the procedure (P = .802; P = .982).

CONCLUSION

Even after procuring and offering potentially good pancreata, nearly half the organs are refused for medical reasons. Acceptance criteria in the Eurotransplant region reveal a conservative attitude toward pancreas acceptance.

Pancreas transplants from donors aged 45 years or older

AIMS

Since donor age of 45 years or more is considered a relative contraindication for pancreas transplantation (PTx), we herein report our experience with these donors.

METHODS

Pancreases from donors aged 45 years or older were used in 16 of 147 PTx procedures (11%). The final decision to accept a graft for PTx was based mainly on the quality of visceral perfusion and the gross appearance of the pancreas and the vessels. There were 9 men and 7 women, ranging in age from 45 to 55 years (average, 48.9 years) who were donors, due to cerebrovascular accidents (n = 11; 68.7%). Among the donor group, 5 patients were receiving multiple vasopressor agents (31.2%), and 2 had a history of cardiac arrest (12.5%). Pancreases were transplanted either simultaneously with a cadaveric kidney (n = 6) or as solitary grafts (n = 10).

RESULTS

After a mean period of cold preservation of 616 minutes (range, 475 to 844 min), delayed endocrine function occurred in 1 recipient (6%), who subsequently achieved insulin independence. Two recipients died suddenly, with functioning grafts. Two further grafts were lost due to portal vein thrombosis (6%) or late arterial thrombosis (6%). Three patients required repeat surgery (18.7%). After a mean follow-up period of 26.6 months, actuarial 1-year and 5-year patient survival rates were 87.5%, with insulin independence in 81.2% and 67.7%, respectively.

CONCLUSIONS

Meticulous donor selection and short preservation times allow the safe use of pancreases procured from donors aged 45 years or older, thus expanding the donor pool for PTx procedures.

Current practices of donor pancreas allocation in the UK: future implications for pancreas and islet transplantation*

Recent refinements in technique mean islet cell transplantation offers the chance of a cure to an increasing patient cohort with diabetes. Such developments put pressure upon the scarce resource of donor organs, with potential competition between the modalities of cellular and solid organ transplantation. This questionnaire based study examines current patterns of donor pancreas procurement and use. Reasons for non procurement are studied together with the attitudes of transplant professionals to pancreas allocation. The minority of potentially useful pancreata are currently made available to either whole pancreas or islet transplant programs. Whilst professionals appreciate the role of each modality, there is a need to define criteria for pancreas allocation to avoid under use of donor organs.

Donor Care before Pancreatic Tissue Transplantation

Publications are reviewed to identify factors related to donor care that may optimize the function of pancreatic tissue (whole or segmental organ or islet cells) after transplantation. Short cold ischemia time, avoidance of hypotension, and treatment of donor hyperglycemia appear to be beneficial, although additional properly designed studies are needed to verify those findings.

A simplified technique for the en bloc procurement of abdominal organs that is suitable for pancreas and small-bowel transplantation

BACKGROUND

Graft shortage makes multiorgan procurement mandatory. We describe the results of a simplified method for the en bloc procurement of multiple organs, which permits isolated transplantation of all abdominal grafts, including the pancreas and the small bowel, to different recipients.

METHODS

Three hundred forty-three multiorgan procurements were done with a simplified en bloc technique.

RESULTS

None of the 1374 grafts that were procured sustained injuries that potentially precluded transplantation. Seventy-two grafts that were procured from 18 donors (5%) who were diagnosed with a neoplasm were discarded. Overall, 339 grafts that were procured from 325 donors were discarded because of specific contraindications, and 963 grafts (74%) were transplanted. Ninety-seven pancreata were transplanted. In 3 instances the pancreas and the small bowel were procured simultaneously and transplanted to different recipients. A total of 287 liver grafts were also transplanted at 13 different institutions. In 42 instances, the liver was not allocated to our center. Forty liver teams (95%) from 11 different institutions agreed to procure their grafts according to the simplified en bloc technique. Our team performed 18 procurements, and a surgeon from the liver transplantation team, who was assisted by one of the members of our team, performed 22 procurements. In all, 576 kidneys were transplanted, either alone or simultaneously, with other abdominal grafts at 15 different institutions.

CONCLUSIONS

This procurement method has high yields, allows pancreas and small-bowel procurement, and can be learned readily.

Underutilization of pancreas donors

BACKGROUND

Transplantation of the pancreas has become the treatment of choice for selected patients with type 1 diabetes mellitus. With the current shortage of cadaver donors and the increasing number of diabetic patients on the transplant waiting list, there is a critical need to optimally use all available pancreas grafts for transplantation. We have therefore explored the use of traditionally "less-than-ideal" pancreas donors, including pediatric (4-10 years), older (>or=45 years), obese (weight >or=200 lb), and non-heart-beating donors and donors with an elevated amylase (75% greater than normal values).

METHODS

A total of 620 primary simultaneous pancreas-kidney transplantations were performed at our center. We analyzed the ratio of livers to pancreata transplanted at our center and compared this to the United Network for Organ Sharing database. Using univariate and multivariate analyses, we then assessed the impact of these less-than-ideal donors on patient survival, graft survival, and postsurgical complications after simultaneous pancreas-kidney transplantation.

RESULTS

A substantial nationwide underutilization of pancreata from donor procurements is demonstrated in the United Network for Organ Sharing database. By using these less-than-ideal donors, the ratio of liver to pancreata procured can be reduced to 1.25:1. Graft survival was not significantly different in patients receiving transplants from obese, non-heart-beating, pediatric, or hyperamylasemic donors compared with grafts from ideal donors. However, grafts from donors 45 years of age or older had significantly lower 1- and 5-year graft survival rates (76% and 65% vs. 90% and 80%, P=0.006).

CONCLUSIONS

This study demonstrates that utilization of pancreas grafts from selected, less-than-ideal donors results in good overall outcomes and could potentially expand the organ donor pool.

Pancreas transplantation: the histologic morphology of graft loss and clinical correlations

BACKGROUND

Graft losses due to leaks, bleeding, thrombosis, infections, and early pancreatitis are grouped together under the category of technical failure. Among these complications, massive vascular thrombosis continues to be the most important cause of early graft loss due to technical failure. Pathological evaluation of most allografts lost early in the posttransplantation period shows vascular thrombosis with associated proportional parenchymal necrosis. The morphological findings in allografts that are considered to be lost due to technical failure has not been systematically addressed. In particular, the role of acute rejection in early graft loss has not been well studied.

METHODS

Seventy-four consecutive pancreas graft pancreatectomies were studied histologically to evaluate for thrombosis (recent versus organized), type of vessel involved by thrombosis (arteries, veins, or both), acute rejection grade, chronic rejection grade, endotheliitis, transplant arteritis, coagulation necrosis, acute pancreatitis, presence of infectious organisms, transplant (obliterative) arteriopathy, neoplasia, relative proportions of alpha and beta islet cells, and immunoglobulin and complement deposition. The histological findings were correlated with donor and recipient data as well as clinical presentation.

RESULTS

In 23 out of 39 grafts lost in the first 4 weeks posttransplantation, the only pathological changes found were vascular thrombosis and bland ischemic parenchymal necrosis. In these cases, no underlying vascular pathology or any other specific histological change was identified. Most of these grafts (78%) were lost in less than 48 hr and all in the first 2 weeks posttransplantation. Massive vascular thrombosis occurring in an otherwise histologically normal pancreas was the most common cause of graft loss in the first 4 weeks posttransplantation (59%). In most of the remaining cases (33%), although the clinical presentation suggested technical failure, there was clear histological evidence that the massive thrombosis resulted from vascular injury due to immune damage (acute and hyperacute rejection). Increased incidence of early graft thrombosis was seen in grafts from older donors and longer cold ischemia times. After the first month posttransplantation, graft pancreatectomies revealed a wider variety of pathological processes that included severe acute rejection, combined acute and chronic rejection, chronic rejection, and infections. Acute and chronic vascular thrombosis in large and small vessels was commonly seen at all times posttransplantation; chronic, organized thrombosis was strongly associated with chronic rejection.

CONCLUSIONS

(a) Early acute thrombosis occurring in a histologically normal pancreas defines a true technical failure. This study showed that acute rejection leading to massive thrombosis, which clinically simulates technical failure, results in a significant proportion of early graft losses. (b) Systematic histological evaluation of failed grafts is absolutely necessary for the accurate classification of the cause of graft loss. (c) There is morphological evidence that chronically ongoing thrombosis is an important, common, contributing factor for late graft loss.

Lessons learned from more than 1,000 pancreas transplants at a single institution

OBJECTIVE

To determine outcome in diabetic pancreas transplant recipients according to risk factors and the surgical techniques and immunosuppressive protocols that evolved during a 33-year period at a single institution.

SUMMARY BACKGROUND DATA

Insulin-dependent diabetes mellitus is associated with a high incidence of management problems and secondary complications. Clinical pancreas transplantation began at the University of Minnesota in 1966, initially with a high failure rate, but outcome improved in parallel with other organ transplants. The authors retrospectively analyzed the factors associated with the increased success rate of pancreas transplants.

METHODS

From December 16, 1966, to March 31, 2000, the authors performed 1,194 pancreas transplants (111 from living donors; 191 retransplants): 498 simultaneous pancreas-kidney (SPK) and 1 simultaneous pancreas-liver transplant; 404 pancreas after kidney (PAK) transplants; and 291 pancreas transplants alone (PTA). The analyses were divided into five eras: era 0, 1966 to 1973 (n = 14), historical; era 1, 1978 to 1986 (n = 148), transition to cyclosporine for immunosuppression, multiple duct management techniques, and only solitary (PAK and PTA) transplants; era 2, 1986 to 1994 (n = 461), all categories (SPK, PAK, and PTA), predominantly bladder drainage for graft duct management, and primarily triple therapy (cyclosporine, azathioprine, and prednisone) for maintenance immunosuppression; era 3, 1994 to 1998 (n = 286), tacrolimus and mycophenolate mofetil used; and era 4, 1998 to 2000 (n = 275), use of daclizumab for induction immunosuppression, primarily enteric drainage for SPK transplants, pretransplant immunosuppression in candidates awaiting PTA.

RESULTS

Patient and primary cadaver pancreas graft functional (insulin-independence) survival rates at 1 year by category and era were as follows: SPK, era 2 (n = 214) versus eras 3 and 4 combined (n = 212), 85% and 64% versus 92% and 79%, respectively; PAK, era 1 (n = 36) versus 2 (n = 61) versus 3 (n = 84) versus 4 (n = 92), 86% and 17%, 98% and 59%, 98% and 76%, and 98% and 81%, respectively; in PTA, era 1 (n = 36) versus 2 (n = 72) versus 3 (n = 30) versus 4 (n = 40), 77% and 31%, 99% and 50%, 90% and 67%, and 100% and 88%, respectively. In eras 3 and 4 combined for primary cadaver SPK transplants, pancreas graft survival rates were significantly higher with bladder drainage (n = 136) than enteric drainage (n = 70), 82% versus 74% at 1 year (P =.03). Increasing recipient age had an adverse effect on outcome only in SPK recipients. Vascular disease was common (in eras 3 and 4, 27% of SPK recipients had a pretransplant myocardial infarction and 40% had a coronary artery bypass); those with no vascular disease had significantly higher patient and graft survival rates in the SPK and PAK categories. Living donor segmental pancreas transplants were associated with higher technically successful graft survival rates in each era, predominately solitary (PAK and PTA) in eras 1 and 2 and SPK in eras 3 and 4. Diabetic secondary complications were ameliorated in some recipients, and quality of life studies showed significant gains after the transplant in all recipient categories.

CONCLUSIONS

Patient and graft survival rates have significantly improved over time as surgical techniques and immunosuppressive protocols have evolved. Eventually, islet transplants will replace pancreas transplants for suitable candidates, but currently pancreas transplants can be applied and should be an option at all stages of diabetes. Early transplants are preferable for labile diabetes, but even patients with advanced complications can benefit.

Partial venous thrombosis of the pancreatic allografts after simultaneous pancreas-kidney transplantation

Despite new advances in transplantation, complete venous thrombosis (VT) of the pancreas after simultaneous pancreas kidney (SPK) transplantation usually results in graft loss. Data are limited regarding the outcome and treatment of partial VT of the pancreas allograft. From July 1994 to December 1999, 126 patients with IDDM/end-stage renal disease underwent SPK with systemic bladder drainage at the University of Miami. We retrospectively reviewed our experience regarding the outcome and treatment options of partial VT of the pancreas allografts. From July 1994 to April 1997, partial VT was not seen in the first 66 SPK patients induced with anti-CD3 rnAb and oral or intravenous (i.v.) tacrolimus (TAC) in the operating room. From May 1997 to June 1999, 14 (29%) out of 48 patients had VT. These cases were identified following the i.v. use of TAC with anti-IL-2R antibody-induction therapy (7/15) or without (7/33). Partial thrombosis of the splenic vein (PTSV) was documented in 10 patients, 2 had complete thrombosis of the splenic vein (CTSV), 1 had partial thrombosis of the superior mesenteric vein (PTSMV), and 1 patient had PTSV and PTSMV. These were identified incidentally during routine color Doppler ultrasonography (CDU). None of these SPK recipients demonstrates a change in clinical parameters. The first 8 patients were systemically heparinized, followed by oral anticoagulation, except 1 patient with CTSV. He progressed to complete thrombosis of the pancreas allograft and was treated with percutaneous thrombectomy and urokinase infusion, followed by heparinization and oral anticoagulation. One patient required exploration for bleeding. In an attempt to reduce the morbidity of heparinization, we treated the next 6 patients with PTSV with aspirin followed by serial CDU. All 14 patients had preservation of the endocrine and exocrine pancreatic functions. CDU showed resolution with recanalization of the thrombosed vein(s). From July 1999 to December 1999, 12 SPK recipients were administered TAC orally with or without induction therapy with anti-IL-2R antibody. So far, in this group, VT has not been identified. In summary, a total of 14 out of 126 patients (11%) had isolated VT with a mean follow-up of 36.4 months. Based on our experience, we suggest that extensive VT after pancreas transplantation, including splenic and superior mesenteric VT, be treated with heparin and subsequent oral anticoagulation for 3 months. For more limited, partial splenic VT, aspirin may be sufficient. Follow-up CDU is critical for a successful outcome. The i.v. use of TAC appears to be a risk factor for the increased incidence of VT. Currently, using IL-2rmAb as induction, TAC is started orally on postoperative days 3 or 4 and aspirin on postoperative day 2.

Allograft pancreatectomy after pancreas transplantation with systemic-bladder versus portal-enteric drainage

From 1989 to 1997, we performed 159 pancreas transplantations (PTXs), including 117 simultaneous kidney PTX (SKPT), 25 PTXs alone (PTA), and 17 sequential PTXs after kidney transplantations (PAKT). A total of 73 PTXs were performed with systemic-bladder (S-B) and 86 with portal-enteric (P-E) drainage. The need for allograft pancreatectomy (PCTY) may be considered as an index of technical morbidity after PTX. A total of 37 PCTYs (23%) were performed at a mean of 4.7 months after PTX. Twenty-seven PCTYs were performed within 1 month, 30 (81%) within 3 months, and the remaining seven more than 6 months after PTX. The incidence of PCTY did not differ according to type of transplantation: simultaneous kidney PTX (SKPT) (23%), PTA (24%), and PAKT (23.5%). Indications for PCTY were thrombosis (23), rejection (9), infection (3), and pancreatitis (2). During the study, a total of 70 pancreas grafts were lost, with PCTY performed in 37 (53%). PCTY was directly related to the timing of graft loss; 77% of grafts lost within 3 months of PTX required PCTY, while 25% of grafts lost after 3 months resulted in PCTY (p < 0.01). The incidence of graft failure resulting in PCTY was similar according to type of transplantation: SKPT (55%), PTA (46%), and PAKT (50%). The incidence of PCTY was also similar according to technique of transplantation: 26% S-B versus 21% P-E, p = NS. However, the incidence of graft failure resulting in PCTY was higher in P-E (69%) versus S-B (43%) (p < 0.05) PTX recipients. Patient and kidney graft survival and pancreas retransplant graft survival rates were higher in PTX recipients with P-E drainage.

CONCLUSIONS

PCTY is performed in over half of cases of pancreas allograft loss and is directly related to the timing and cause of graft loss. The incidence of PCTY is neither related to the type nor technique of PTX. The lower overall incidence of graft loss after PTX with P-E drainage is offset by a higher incidence of PCTY in these grafts that fail. These results suggest that whole-organ PTX with P-E drainage does not place the patient at an increased risk for PCTY and does not preclude successful pancreas retransplantation.