Current state of pancreas transplantation in Japan based on the nationwide registry

Size-mismatched transplantation from large donors to small recipients is associated with pancreas graft thrombosis: A retrospective national observational study

INTRODUCTION

Donor-recipient (D/R) size mismatch has been evaluated for a number of organs but not for pancreas transplantation.

METHODS

We retrospectively evaluated 438 patients who had undergone pancreas transplantation. The D/R body surface area (BSA) ratio was calculated, and the relationship between the ratio and graft prognosis was evaluated. We divided the patients into two groups and evaluated graft survival. The incidence of pancreas graft thrombosis resulting in graft failure within 14 days and 1-year graft survival were compared using Kaplan-Meier curves, and the prognostic factors associated with graft thrombosis were identified by univariate and multivariate analyses.

RESULTS

The mean/median donor and recipient BSAs were 1.63 m2 /1.65 m2 , and 1.57 m2 /1.55 m2 , respectively; the mean and median D/R BSAs were both 1.05. The receiver operating characteristic curve cutoff for the D/R BSA ratio was 1.09, and significant differences were identified between patients with ratios of ≥1.09 (high group) versus <1.09 (low group). The incidence of graft thrombosis resulting in pancreas graft failure within 14 days was significantly higher in the high group than in the low group (p < .01). One-year overall and death-censored pancreas graft survival were significantly higher in the low group than in the high group (p < .01). Multivariate analysis identified recipient height, donor BSA, and donor hemoglobin A1c as significant independent factors for graft thrombosis. Cubic spline curve analysis indicated an increased risk of graft thrombosis with increasing D/R BSA ratio.

CONCLUSION

D/R size mismatch is associated with graft thrombosis after pancreas transplantation.

Noninvasive evaluation of donor and native pancreases following simultaneous pancreas-kidney transplantation using positron emission tomography/computed tomography

It is crucial to develop practical and noninvasive methods to assess the functional beta-cell mass in a donor pancreas, in which monitoring and precise evaluation is challenging. A patient with type 1 diabetes underwent noninvasive imaging following simultaneous kidney-pancreas transplantation with positron emission tomography/computed tomography (PET/CT) using an exendin-based probe, [18 F]FB(ePEG12)12-exendin-4. Following transplantation, PET imaging with [18 F]FB(ePEG12)12-exendin-4 revealed simultaneous and distinct accumulations in the donor and native pancreases. The pancreases were outlined at a reasonable distance from the surrounding organs using [18 F]FB(ePEG12)12-exendin-4 whole-body maximum intensity projection and axial PET images. At 1 and 2 h after [18 F]FB(ePEG12)12-exendin-4 administration, the mean standardized uptake values were 2.96 and 3.08, respectively, in the donor pancreas and 1.97 and 2.25, respectively, in the native pancreas. [18 F]FB(ePEG12)12-exendin-4 positron emission tomography imaging allowed repeatable and quantitative assessment of beta-cell mass following simultaneous kidney-pancreas transplantation.

Utilization of the Pancreas From Donors With an Extremely High Pancreas Donor Risk Index: Report of the National Registry of Pancreas Transplantation

Pancreas transplants from expanded criteria donors are performed widely in Japan because there is a shortage of brain-dead donors. However, the effectiveness of this strategy is unknown. We retrospectively studied 371 pancreas transplants to evaluate the possibility of pancreas transplantation from expanded criteria donors by the Pancreas Donor Risk Index (PDRI). Patients were divided into five groups according to quintiles of PDRI values (Q1-Q5). The 1-year pancreas graft survival rates were 94.5% for Q1, 91.9% for Q2, 90.5% for Q3, 89.3% for Q4, and 79.6% for Q5, and were significantly lower with a lower PDRI (p = 0.04). A multivariate analysis showed that the PDRI, donor hemoglobin A1c values, and pancreas transplantation alone significantly predicted 1-year pancreas graft survival (all p < 0.05). Spline curve analysis showed that the PDRI was incrementally associated with an increased risk of 1-year graft failure. In the group with a PDRI ≥ 2.87, 8/56 patients had graft failures within 1 month, and all were due to graft thrombosis. The PDRI is a prognostic factor related to the 1-year graft survival rate. However, pancreas transplantation from high-PDRI donors shows acceptable results and could be an alternative when the donor pool is insufficient.

Clinical Significance of the Interposition Graft for Reconstruction Between the Common Hepatic Artery and Gastroduodenal Artery for Arterial Patency of the Pancreas Graft in Pancreas Transplantation

BACKGROUND

Due to the limited number of organ donations from deceased donors in Japan, pancreas grafts for pancreas transplantation (PTx) are frequently harvested from the donor in the same donation surgery as the liver graft. In such a situation, the common hepatic artery (CHA) and gastroduodenal artery (GDA) are dissected, resulting in decreased blood flow to the head of the pancreas graft. Therefore, GDA reconstruction using an interposition graft (I-graft) between the CHA and GDA has been traditionally performed to maintain blood flow. This study investigated the clinical significance of GDA reconstruction with the I-graft regarding the arterial patency of the pancreas graft in patients after PTx.

METHODS

Fifty-seven patients underwent PTx for type 1 diabetes mellitus at our hospital between 2000 and 2021. Twenty-four cases in which GDA reconstruction was performed using the I-graft and artery blood flow of the pancreas graft was evaluated by contrast-enhanced computed tomography or angiography were included in this study.

RESULTS

The patency of the I-graft was 95.8%, and only one patient had a thrombus in the I-graft. Nineteen patients (79.2%) had no thrombus in the artery of the pancreas graft; the other five cases had thrombus in the superior mesenteric artery (SMA). The patient with the thrombus in the I-graft required graftectomy for the pancreas graft.

CONCLUSIONS

The patency of the I-graft was favorable. Furthermore, the clinical significance of the GDA reconstruction with the I-graft is suggested to maintain blood flow in the pancreas head if the SMA is occluded.

Impact of Cytomegalovirus Infection and Disease on Graft Loss After Pancreas Transplantation: A Single-Institution Study in Japan

BACKGROUND

Cytomegalovirus (CMV) is one of the most frequent infections after pancreas transplantation (PTx), and it is unclear whether CMV infection is associated with pancreas graft loss. A limited number of studies about the relationship between CMV infection and pancreas graft loss have been reported from Western countries, but there have been no reports from Japan. This study investigated the relationship between CMV infection and pancreas graft loss after PTx in a single Japanese institution.

METHODS

This study included 58 patients who underwent PTx from deceased donors from April 2000 to March 2021 in our institution. We assessed pancreas graft loss based on CMV infection and disease and investigated the causes of graft loss, the time of onset of CMV disease, and the time of graft loss for each case.

RESULTS

The numbers of patients in the 4 categories of donor (D) and recipient (R) pretransplant anti-CMV antibody status were as follows: 4 (6.9%) in the D-/R- group, 6 (10.3%) in the D-/R+ group, 34 (58.6%) in the D+/R+ group, and 14 (24.1%) in the D+/R- group. Of the 58 patients, 74.1% and 44.1% received diagnoses of CMV infection and disease after PTx, respectively. There were no significant differences in the survival rates of pancreas graft loss stratified by CMV infection (P = .1809) or disease (P = .6241).

CONCLUSIONS

This study suggests that CMV infection and disease had no significant influence on pancreas graft loss in this Japanese institution.

Clinical Impact of Ischemic Time of the Pancreas or Kidney Graft on Simultaneous Pancreas-Kidney Transplantation: A Single-Institution Study in Japan

BACKGROUND

Total ischemic time (TIT) potentially affects graft survival in organ transplantation. However, in simultaneous pancreas-kidney (SPK) transplantation, the impact of TIT of the pancreas (P-TIT) and kidney graft (K-TIT) on posttransplant outcomes remains unclear. This study investigated the impact of P-TIT and K-TIT on postoperative outcomes in patients after SPK at our institution in Japan.

PATIENTS AND METHODS

This study included 52 patients who underwent SPK at our hospital from April 2000 to March 2022. Of this patient group, the 52 patients were divided into a short P-TIT group (n = 25), long P-TIT group (n = 27), short K-TIT group (n = 42), and long K-TIT group (n = 10). Short- and long-term postoperative outcomes were compared between the groups.

RESULTS

The long K-TIT group had a significantly higher rate of patients who did not urinate intraoperatively (50% vs 7%; P = .0007) and those requiring postoperative hemodialysis (80% vs 38%; P = .0169), as well as a significant longer duration of postoperative hemodialysis (97 ± 147 days vs 6 ± 9 days; P = .0016). These were not significantly different between the short and long P-TIT groups. Kidney or pancreas graft survival was not significantly different between the short and long P-TIT or K-TIT groups.

CONCLUSIONS

Patients with prolonged K-TIT during SPK exhibited poor short-term outcomes, but no significant influence of K-TIT was identified on long-term outcomes. The P-TIT did not affect any significant outcomes. These results indicate that shortening K-TIT may improve short-term outcomes after SPK.

Impact of Decompression Tube Placement in Duodenal Graft on Graft Perforation After Pancreas Transplantation

BACKGROUND

Duodenal graft perforation (DGP) is a serious complication after pancreas transplantation (PTx) and can lead to pancreas graft loss. Here, we investigated whether the placement of a decompression tube (DT) for the duodenal graft during PTx is clinically useful for preventing DGP.

METHODS

This study included 54 patients who received PTx for type 1 diabetes at our institution between 2000 and 2020. Among these cases, 28 included DT placement (51.9%; DT group), and the remaining 26 without DT placement (non-DT group) were used as historical controls for comparison to the cases with DT placement.

RESULTS

Among all 54 cases, DGP occurred in 7 (13.0%). The DGP incidence did not significantly differ between the DT group (10.7%, 3/28 cases) and the non-DT group (15.4%, 4/26 cases) (P = .6994). Logistic regression analysis showed that DT placement did not affect DGP risk. Notably, 5 cases in the DT group (17.9%) exhibited adverse effects that were likely the result of DT placement, including bleeding from tube contact (2 cases), enterocutaneous fistula at the DT placement site (2 cases), and intraabdominal abscess around the DT site (1 case). Pancreas graft survival after PTx did not significantly differ between the DT and non-DT groups (P = .6260).

CONCLUSIONS

The DT group did not exhibit superior outcomes compared with the non-DT group. This result suggests that DT placement did not have a clinical impact on DGP prevention after PTx.

Different timing and risk factors of cause-specific pancreas graft loss after simultaneous pancreas kidney transplantation

In cases after pancreas transplantation (PTx), the pancreas graft might be lost for various reasons, including a pancreatoduodenal graft-related complication or patient death with a functioning graft. Although the causes seem to have distinct characteristics, the causes of pancreas graft loss have not been characterized. This study aimed to characterize the causes of pancreas graft loss by analyzing data from a Japanese nationwide registry. This study included 391 patients who received simultaneous pancreas-kidney transplantation among 461 patients with PTx during the study period in approved institutions in Japan. We characterized each cause in terms of the timing of the cause-specific graft loss and preoperative factors associated with graft loss based on nationwide data from a Japanese nationwide registry. Among the 391 cases, 113 lost the pancreas graft due to patient death with a functioning graft (DWFG; n = 34, 44.2%), graft thrombus (n = 22, 28.6%), or chronic rejection (CR; n = 7, 9.1%). Average (± standard deviation) time from PTx to graft loss due to DWFG, graft thrombus, and CR was 3.70 ± 4.36, 0.02 ± 0.01, and 2.37 ± 2.08 years, respectively. Duration of type 1 diabetes mellitus and donor body mass index were significantly associated with pancreas graft loss due to DWFG and graft thrombus, respectively. This characterization showed that the timing and preoperative factors associated with pancreas graft loss were significantly different for different causes of graft loss. These results may inform PTx follow-up protocols to ensure that appropriate care is based on the cause of graft loss.

Recurrent Cytomegalovirus Infection Controlled by the Introduction of Everolimus in a Simultaneous Pancreas-Kidney Transplantation Recipient: A Case Report

In simultaneous pancreas-kidney transplantation (SPK) recipients, cytomegalovirus (CMV) infection is a major complication that has been associated with the use of tacrolimus (TAC)-based immunosuppression. As one of the immunosuppressive drug options, the use of mammalian target of rapamycin inhibitors (mTORi) results in reduced rates of CMV infection in the field of solid organ transplantation. However, little is known about mTORi usage in pancreas transplantation. We report a case of recurrent CMV infection that was controlled by the introduction of mTORi (everolimus) in addition to a TAC-based immunosuppression regimen in SPK. A 52-year-old man underwent SPK. Graft duodenal perforation occurred on the 13th day of surgery, and graft duodenal resection was performed after long-term abscess drainage treatment. After graft duodenal resection, he was diagnosed with CMV viremia, and valganciclovir was started. However, because of recurrent febrile neutropenia caused by cytopenia as a side effect of valganciclovir, there was a repeated need for granulocyte-colony stimulating factor treatment. Immunosuppressive drug taper adjustment was attempted to control recurrent CMV viremia, and everolimus was introduced with the aim of reducing the dose of TAC and mycophenolate mofetil. This resulted in a continuously negative CMV antigenemia test and a stable general condition. Understanding the characteristics of various immunosuppressive agents and appropriately controlling and managing infectious diseases is crucial for the good postoperative management of patients with SPK.

Evaluation of the Efficacy and Effects of Common Hepatic Artery Reconstruction in Pancreas Transplantation: A Randomized Controlled Trial

Maintenance of postoperative graft flow is important in pancreas transplantation. In Japan, reconstruction of the common hepatic artery is performed primarily to increase perfusion in the pancreatic head. We investigated the effects of common hepatic artery reconstruction on patient and graft survival and endocrine functions. Twenty-nine cases of pancreas transplantation were registered in the clinical trial. Of the 29 cases, four were excluded because of the risk of ischemia without reconstruction or complicated reconstruction due to a narrow artery. A total of 25 cases were randomized into two groups: 13 in the non-reconstructed group and 12 in the reconstructed group. The 1-year patient survival and graft survival rates of the non-reconstructed and reconstructed groups were 92.3% and 83.3%, and 91.7% and 82.5%, respectively. The incidence of complications in the two groups was comparable, with 38.5% (5/13 cases) in the non-reconstructed group and 33.3% (4/12 cases) in the reconstructed group. The results of the glucagon stimulation test and oral glucose tolerance test at 1 month and 1 year post-transplantation were comparable. Common hepatic artery reconstruction is not essential unless there is risk of ischemia. This study was registered at the University Hospital Medical Information Network Clinical Trials Registry under UMIN000027213.

The History of Clinical Islet Transplantation in Japan

Islet transplantation shows the promise of being capable of relieving glucose instability and improving QOL of patients with type 1 diabetes that cannot be controlled due to severe hypoglycemia unawareness. In Japan, following the first human islet isolation from a donor after cardiac death in 2003 and the first clinical islet transplantation in 2004, islet transplantation was performed for the improvement of type 1 diabetes as a single-center trial in several centers. Although it was discontinued due to the possibility of contamination of collagenase by bovine brain component in 2007, the phase II clinical trial of islet transplantation started using ATG induction and a TNF-α inhibition protocol in 2012. The primary endpoints of this trial were the proportion of patients with HbA1c < 7.4% and freedom from severe hypoglycemic events at one year after the first islet cell infusion. In an interim analysis, this endpoint was achieved in 75% of cases. In April 2020, clinical islet transplantation was finally covered by health insurance in Japan, thanks to these outcomes. We herein introduce more than 20 years of history of clinical islet transplantation in Japan.