Laparoscopic Biopsies in Pancreas Transplantation

Exploring the current provision of pancreatic transplantations in low- and middle-income countries: Current landscape, challenges, future prospects

This comprehensive review addresses the global health challenge of disparities in pancreas transplant access, particularly in low- and middle-income countries (LMICs) compared to high-income countries. Despite advancements in surgical techniques and immunosuppression for procedures like simultaneous pancreas-kidney, pancreas-after-kidney, and pancreas-transplant alone, LMICs face significant challenges, including limited infrastructure, financial constraints, and a shortage of skilled medical professionals. Donation after brain death remains constrained by sociocultural barriers. Region-specific analyses highlight progress in Latin America, Asia, Russia, and South Africa, showcasing the regional disparities in access and outcomes. Future prospects involve minimally invasive surgeries, telemedicine for enhanced post-operative care, international collaborations with organizations like the European Union of Medical Specialists, and robust funding networks to improve organ availability. In conclusion, the review underscores the importance of multifaceted strategies to address economic, sociocultural, and infrastructural barriers, aiming to improve accessibility, quality, and effectiveness of pancreas transplantation services in LMICs.

Accessibility of Percutaneous Biopsy in Retrocolic-Placed Pancreatic Grafts With a Duodeno-Duodenostomy

Duodeno-duodenostomy (DD) has been proposed as a more physiological alternative to conventional duodeno-jejunostomy (DJ) for pancreas transplantation. Accessibility of percutaneous biopsies in these grafts has not yet been assessed. We conducted a retrospective study including all pancreatic percutaneous graft biopsies requested between November 2009 and July 2021. Whenever possible, biopsies were performed under ultrasound (US) guidance or computed tomography (CT) guidance when the US approach failed. Patients were classified into two groups according to surgical technique (DJ and DD). Accessibility, success for histological diagnosis and complications were compared. Biopsy was performed in 93/136 (68.4%) patients in the DJ group and 116/132 (87.9%) of the DD group (p = 0.0001). The graft was not accessible for biopsy mainly due to intestinal loop interposition (n = 29 DJ, n = 10 DD). Adequate sample for histological diagnosis was obtained in 86/93 (92.5%) of the DJ group and 102/116 (87.9%) of the DD group (p = 0.2777). One minor complication was noted in the DD group. The retrocolic position of the DD pancreatic graft does not limit access to percutaneous biopsy. This is a safe technique with a high histological diagnostic success rate.

Indications, Techniques, and Barriers for Pancreas Transplant Biopsy: A Consensus Perspective From a Survey of US Centers

BACKGROUND

Pancreas transplant biopsy practices for the diagnosis of rejection or other pathologies are not well described.

METHODS

We conducted a survey of staff at US pancreas transplant programs (March 22, 2022, to August 22, 2022) to assess current program practices and perceptions about the utility and challenges in the performance and interpretation of pancreas allograft biopsies.

RESULTS

Respondents represented 65% (76/117) of active adult pancreas transplant programs, capturing 66% of recent pancreas transplant volume in the United States. Participants were most often nephrologists (52%), followed by surgeons (46%), and other staff (4%). Pancreas allograft biopsies were performed mostly by interventional radiologists (74%), followed by surgeons (11%), nephrologists (8%), and gastroenterologists (1%). Limitations in the radiologist's or biopsy performer's comfort level or expertise to safely perform a biopsy, or to obtain sufficient/adequate samples were the two most common challenges with pancreas transplant biopsies. Pancreas transplant biopsies were read by local pathologists at a majority (86%) of centers. Challenges reported with pancreas biopsy interpretation included poor reliability, lack of reporting of C4d staining, lack of reporting of rejection grading, and inconclusive interpretation of the biopsy. Staff at a third of responding programs (34%) stated that they rarely or never perform pancreas allograft biopsies and treat presumed rejection empirically.

CONCLUSIONS

This national survey identified significant variation in clinical practices related to pancreas allograft biopsies and potential barriers to pancreas transplant utilization across the United States. Consideration of strategies to improve program experience with percutaneous pancreas biopsy and to support optimal management of pancreas allograft rejection informed by histology is warranted.

International Survey of Clinical Monitoring Practices in Pancreas and Islet Transplantation

BACKGROUND

The long-term outcomes of both pancreas and islet allotransplantation have been compromised by difficulties in the detection of early graft dysfunction at a time when a clinical intervention can prevent further deterioration and preserve allograft function. The lack of standardized strategies for monitoring pancreas and islet allograft function prompted an international survey established by an International Pancreas and Islet Transplant Association/European Pancreas and Islet Transplant Association working group.

METHODS

A global survey was administered to 24 pancreas and 18 islet programs using Redcap. The survey addressed protocolized and for-cause immunologic and metabolic monitoring strategies following pancreas and islet allotransplantation. All invited programs completed the survey.

RESULTS

The survey identified that in both pancreas and islet allograft programs, protocolized clinical monitoring practices included assessing body weight, fasting glucose/C-peptide, hemoglobin A1c, and donor-specific antibody. Protocolized monitoring in islet transplant programs relied on the addition of mixed meal tolerance test, continuous glucose monitoring, and autoantibody titers. In the setting of either suspicion for rejection or serially increasing hemoglobin A1c/fasting glucose levels postpancreas transplant, Doppler ultrasound, computed tomography, autoantibody titers, and pancreas graft biopsy were identified as adjunctive strategies to protocolized monitoring studies. No additional assays were identified in the setting of serially increasing hemoglobin A1c levels postislet transplantation.

CONCLUSIONS

This international survey identifies common immunologic and metabolic monitoring strategies utilized for protocol and for cause following pancreas and islet transplantation. In the absence of any formal studies to assess the efficacy of immunologic and metabolic testing to detect early allograft dysfunction, it can serve as a guidance document for developing monitoring algorithms following beta-cell replacement.

[Pancreas transplantation-clinic, technique, and histological assessment]

BACKGROUND

In Germany pancreas transplants are performed in only a few selected and specialized centres, usually combined with a kidney transplant. Knowlegde of the indications for and techniques of transplantation as well as of the histopathological assessment for rejection in pancreas and duodenal biopsies is not very widespread.

AIM

To give an overview of the development and status quo in pancreas-kidney-transplantation in Germany summarizing the experience of the largest German pancreas transplant centre and to give a résumé of the results of histological diagnoses of biopsy specimens submitted between 06/2017 and 12/2020. Moreover, a detailed description and illustration of histological findings is included.

MATERIAL AND METHODS

A thorough literature search for aspects of the history, technique and indication for pancreas transplantation was performed and discussed in the context of the local experience and technical particularities specific for the transplant centre in Bochum. The occurrence of complications was compared with international reports. Results of pancreas and duodenal biopsies submitted to Erlangen between 06/2017 and 12/2020 for histological evaluation, which were evaluated according to the Banff classification, were summarized. For a better understanding key histological findings of pancreas rejection and differential diagnoses were illustrated and discussed.

RESULTS

A total of 93 pancreas transplant specimens and 3 duodenal biopsies were included. 34.4% of pancreas specimens did not contain representative material for a diagnosis. In the remaining 61 biopsies 24.6% showed no rejection, 62.3% were diagnosed with acute T-cell mediated rejection (TCMR) and 8.2% with signs suspicious of antibody-mediated rejection (ABMR). Acute acinary epithelial injury was seen in 59%, pancreatitis in 8.2% and allograft fibrosis was reported in as many as 54.1%. Calcineurin-inhibitor toxicity was discussed in only 4.9%.

CONCLUSION

Pancreas-kidney-transplantation and standardized histological assessment of the transplanted pancreas or rarely duodenum with reporting according to the updated Banff classification of pancreas transplants or previous reports of duodenal rejection are important mainstays in the management of patients with diabetes.

CT fluoroscopy-guided pancreas transplant biopsies: a retrospective evaluation of predictors of complications and success rates

To identify predictors of biopsy success and complications in CT-guided pancreas transplant (PTX) core biopsy. We retrospectively identified all CT fluoroscopy-guided PTX biopsies performed at our institution (2000-2017) and included 187 biopsies in 99 patients. Potential predictors related to patient characteristics (age, gender, body mass index (BMI), PTX age, PTX volume) and procedure characteristics (biopsy depth, needle size, access path, number of samples, interventionalist's experience) were correlated with biopsy success (sufficient tissue for histologic diagnosis) and the occurrence of complications. Biopsy success (72.2%) was more likely to be obtained in men [+25.3% (10.9, 39.7)] and when the intervention was performed by an experienced interventionalist [+27.2% (8.1, 46.2)]. Complications (5.9%) occurred more frequently in patients with higher PTX age [OR: 1.014 (1.002, 1.026)] and when many (3-4) tissue samples were obtained [+8.7% (-2.3, 19.7)]. Multivariable regression analysis confirmed male gender [OR: 3.741 (1.736, 8.059)] and high experience [OR: 2.923 (1.255, 6.808)] (biopsy success) as well as older PTX age [OR: 1.019 (1.002, 1.035)] and obtaining many samples [OR: 4.880 (1.240, 19.203)] (complications) as independent predictors. Our results suggest that CT-guided PTX biopsy should be performed by an experienced interventionalist to achieve higher success rates, and not more than two tissue samples should be obtained to reduce complications. Caution is in order in patients with older transplants because of higher complication rates.

Anti-Hla donor-specific antibody monitoring in pancreas transplantation: Role of protocol biopsies

In kidney transplantation, de novo donor-specific antibodies (DSA) correlate with poor graft survival, and Consensus Guidelines recommend a protocol biopsy. In pancreas transplantation, DSA are also associated with poor graft outcomes; however, there are no recommendations on protocol biopsies. We started an antibody screening protocol on pancreas transplant patients at 0, 3, 6, 12 months, and yearly. Patients with DSA or high MFI non-DSA were considered for protocol biopsies of both organs. Results: 143 pancreas recipients were screened. 84 patients had negative antibodies throughout the study, 11 patients were found to have antibodies at graft dysfunction, and 48 patients had positive antibodies at screening without acute organ dysfunction (study group). Among the 30 non-DSA patients, 9 had protocol simultaneous pancreas and kidney biopsies performed with negative results in all of them. In contrast, among the 18 DSA patients, 15 had these biopsies performed, and 47% presented with subclinical rejection of the kidney, the pancreas, or both. In addition, some of the DSA patients without a protocol biopsy presented with rejection during the first 15 months of follow-up. Conclusion: We conclude that protocol biopsies of both grafts may play a role in the follow-up of pancreas transplant patients with de novo DSA appearance.

Hypertension, but not body mass index, is predictive of increased pancreatic lipid content and islet dysfunction

Pancreatic steatosis is thought to be a negative risk factor for pancreas transplant outcomes. Despite considering donor body mass index (BMI) and the visualization of intercalated fat as indicators of donor pancreas lipid content, transplant surgeons do not use a quantitative method to directly measure steatosis when deciding to transplant a pancreas. In this study, we used nondiabetic human pancreata donated for research to measure the pancreatic and islet-specific lipid content to determine which clinical markers correlate best with lipid content. Interestingly, we found that BMI and age correlate with increased pancreatic lipid content (Panc-LC) in men, but not women. Our findings further suggest that total Panc-LC correlates with an increase in islet lipid content for both men and women. We noted that pancreata donated from individuals with a history of hypertension have increased Panc-LC independent of donor BMI or sex. Moreover, we identify hypertension as a risk factor for reduced islet function after islet isolation. Together, our findings emphasize differences in pancreas graft quality related to pancreatic and islet lipid content, which may not be predicted by assessing BMI alone but may be influenced by a donor history of hypertension.

Pancreas allograft biopsies procedure in the management of pancreas transplant recipients

Pancreas transplantation is an effective therapy for diabetic patients, which can significantly improve the survival rate and quality of life of diabetic patients. According to the international registration of pancreas transplantation center, the global total pancreas transplantation has reached more than 80,000 cases by 2017, including pure pancreas transplantation and simultaneous pancreas-kidney transplantation (SPK). With the development and application of a new type of immunosuppressant, with the gradual maturity of organ preservation technology and surgical technology, the pancreas transplantation has rapidly on a global scale. However, pancreas transplantation still has more problems than limit its development compared with other organ transplantation. For example, the early diagnosis and treatment of pancreatic rejection are of considerable significance to the prognosis of pancreas transplantation. Some surveillance methods of diagnosis have been used increasingly, among which the histopathological diagnosis is particularly important. The first Banff schema for the histological diagnosis of pancreas rejection has been published, which primarily dealt with the diagnosis of acute T-cell-mediated rejection (ACMR). In recent years, antibody-mediated rejection (AMR) has been more emphasized as the primary cause of graft failure. The Banff pancreas allograft rejection grading schema was updated in 2011 by a broad-based multidisciplinary panel, presenting comprehensive guidelines for the diagnosis of AMR.

Protocol Duodenal Graft Biopsies Aid Pancreas Graft Surveillance

BACKGROUND

Histological evaluation of the pancreas graft is usually done on demand resulting in significant delays. This analysis reports on endoscopic protocol duodenal graft biopsies at regular intervals to determine feasibility, safety, and monitoring benefits.

METHODS

Protocol duodenal graft biopsies in 27 consecutive pancreas transplants (10 simultaneous pancreas kidney [SPK], 17 pancreas after kidney [PAK]) with a follow-up of a minimum of 12 months were performed at days 14, 30, 90, 180, 360, 430. University of Pittsburgh Medical Center classification for intestinal rejection was used. C4d staining was performed when antibody-mediated rejection was suspected.

RESULTS

Overall patient and pancreas graft survival was 100% and 93% at a mean follow-up of 2.8 years. One hundred sixty-seven endoscopic biopsy procedures were performed in 27 grafts without any complication. Biopsies revealed rejection in 3 (30%) SPK recipients and in 15 (82%) of PAK recipients as early as 14 days posttransplant. Two patients underwent PAK retransplantation diagnosed with acute rejection at day 180. All except 1 recipient being treated for rejection, showed histological improvement following antirejection treatment. Following transient treatment success, a total of 3 pancreas grafts were lost for immunological reason. One loss was immediate despite antirejection treatment, 1 secondary to nonresolving rejection at 7 months and the third due to recurrent rejection 15 months posttransplantation. Additionally, biopsies detected vascular (venous thrombosis) and overimmunosuppression (cytomegalovirus infection) complications.

CONCLUSIONS

Protocol graft duodenal biopsies detect complications after whole-organ pancreas transplantation, are useful in guiding therapy, and carry potential for improving outcome.

Graft dysfunction in simultaneous pancreas kidney transplantation (SPK): Results of concurrent kidney and pancreas allograft biopsies

Simultaneous pancreas and kidney transplants offer significant therapeutic advantages but present a diagnostic approach dilemma in the diagnosis of rejection. Because both organs are from the same donor, the kidney has been treated traditionally as the "sentinel" organ to biopsy, presumably representing the status of both allografts. Truly concurrent biopsy studies, however, are needed to confirm this hypothesis. We examined 101 concurrent biopsies from 70 patients with dysfunction in either or both organs. Results showed concurrent rejection in 23 of 57 (40%) of cases with rejection; 19 of 57 (33.5%) and 15 of 57 (26.5%) showed kidney or pancreas only rejection, respectively. The degree and type of rejection differed in the majority (13 of 23, 56.5%) of cases with concurrent rejection, with the pancreas more often showing higher rejection grade. Taking into account pancreas dysfunction, a positive kidney biopsy should correctly predict pancreas rejection in 86% of the instances. However, the lack of complete concordance between the 2 organs, the discrepancies in grade and type of rejection, and the tendency for higher rejection grades in concurrent or pancreas only rejections, all support the rationale for pancreas biopsies. The latter provide additional data on the overall status of the organ, as well as information on nonrejection-related pathologies.

Pancreas transplant rejection episodes are not revealed by biopsies of the donor duodenum in a prospective study with paired biopsies

The surgical technique with duodeno-duodenal enteroanastomosis of pancreas transplants allows for representative endoscopic ultrasound-guided needle biopsies of the donor duodenum and the pancreas graft. We assessed whether histological findings in transplanted donor duodenal biopsies can indicate rejection in the transplanted pancreas. Since September 2012, a duodeno-duodenal enteroanastomosis has been the default technique for pancreas transplantations at our center. In 67 recipients we prospectively examined 113 endoscopic ultrasound-guided procedures with representative biopsies from the duodenum grafts and the pancreas grafts (97 per protocol and 16 on indication). All graft biopsies were evaluated according to established rejection criteria. A total of 22 biopsy-proven pancreas rejections were detected, with 2 matching duodenal biopsies showing rejection. This gives a sensitivity of 9% for detection of a pancreas rejection by duodenal biopsies. The other matching duodenal biopsies were either normal (n = 13) or indeterminate (n = 7). Rejection of the donor duodenum was found in only 6/113 biopsies, with 2 concurrent pancreas rejections. In conclusion, the donor duodenum is not a useful reporter organ for rejection in the pancreas graft.