Posttransplant lymphoproliferative disorder following pancreas transplantation

Transplantation for type 1 diabetes: radiologist's primer on islet, pancreas and pancreas-kidney transplantation imaging

Whole-organ pancreas, pancreatic-kidney and islet transplantation are surgical therapeutic options for the treatment of type 1 diabetes. They can enable effective glycemic control, improve quality of life and delay/reduce the secondary complications of type 1 diabetes mellitus. Radiologists are integral members of the multidisciplinary transplantation team involved in these procedures, with multimodality imaging serving as the mainstay for early recognition and management of transplant related complications. This review highlights the transplantation procedures available for patients with type 1 Diabetes Mellitus with a focus on the imaging appearance of transplantation-related complications.

Comprehensive review of imaging in pancreas transplantation: a primer for radiologists

Pancreas transplantation is a complex surgical procedure performed to restore normoglycemia in patients with type 1 diabetes and includes whole/segmental organ transplant and islet cell transplantation (ICT). In the United States, simultaneous pancreas-kidney transplant (SPK) is most commonly performed due to the higher occurrence of end-stage renal disease in diabetic patients. Understanding the surgical technique and postoperative anatomy is imperative for effective and accurate surveillance following transplantation. Imaging plays an essential role in patients with pancreatic transplants and is often used to evaluate viability, vascular and parenchymal anatomy, and identify potential complications. Imaging techniques such as ultrasound, color and spectral Doppler, computed tomography (CT), magnetic resonance imaging (MRI), and angiography have a complementary role in the postoperative evaluation following a pancreas transplant. The common complications after a whole organ pancreas transplant include vascular thrombosis, graft rejection, pancreatitis, and infections. Complications can be classified into vascular (partial or complete venous thrombosis, arterial thrombosis, stenosis or pseudoaneurysm), parenchymal (pancreatitis, graft rejection), and bowel-related or miscellaneous causes (bowel obstruction, anastomotic leak, and peripancreatic fluid collections). Islet cell transplantation is an innovative therapy for patients with type 1 diabetes. It involves isolating insulin-producing islet cells from donor pancreas and transplanting into recipients, to provide long-term insulin independence or significantly reduce insulin requirements. In recent years, isolation techniques, immunosuppressive regimens, and post-transplant monitoring advancements have propelled ICT as a viable therapeutic option. This comprehensive review aims to provide insights into the current state-of-the-art imaging techniques discussing both normal and abnormal features following pancreas transplantation.

Technology and Transplants: Troubleshooting Insulin Pumps and Pancreas Transplants in the Emergency Department

Diabetes management has continued to evolve with new treatments and technology. This article discusses the approach to evaluation and management of two distinctive subsets of patients: (1) patients who manage their diabetes with an insulin pump (artificial pancreas) and (2) patients who have received a pancreas transplant. The most current literature is reviewed and pearls and pitfalls distinctive to these two patient populations are discussed. Relevant diagnostics are reviewed with emphasis on recognition of complications faced in the emergency department management of these unique patient populations.

Ultrasound of pancreatic transplant complications: a primer for radiologists

Pancreatic transplantation is an established treatment for patients with type 1 diabetes patients and select type 2 diabetes patients, with excellent survival rates as graft health is evaluated through regular imaging and early detection of complications. Amongst the various imaging methods that may aid in diagnosis of pancreatic transplant complications, ultrasound is a widely available, quick, portable, and cost-effective technique, often used as the sole method to assess for pancreatic transplant complications. When assessing a patient with a pancreatic transplant, the radiologist should be methodical in assessing the vasculature, the pancreatic parenchyma, and the peripancreatic regions. Complications can be categorised based on time from transplant and type of complications, and include vascular, parenchymal, and enteric/anastomotic complications. Doppler has a major role in the diagnosis of vascular complications including arterial and venous thrombosis, arterial stenosis, pseudoaneurysms, and haematomas. Pancreatic complications include rejections and pancreatitis, and are often diagnosed through a combination of clinical, laboratory, and imaging findings, such as pancreatic heterogeneity or the presence of pancreatic pseudocysts. Enteric/anastomotic complications include leaks and bowel obstructions, and may require cross-sectional imaging in addition to ultrasound. This review covers the most common and high-impact vascular, parenchymal, and enteric/anastomotic complications that should be considered in every radiologist's search pattern when assessing a pancreatic graft, as well as their respective postoperative timeframes.

Preneoplastic Lesion in a Pancreas Allograft: Dilemma for the Pancreas Transplant Surgeon

Although the relationship between immunosuppression and cancer risk is well-documented, the association between immunosuppression and the development of preneoplastic lesions (PNL) is less clear. PNLs pose a unique clinical conundrum in the transplanted pancreas because their prevalence in the general population is not infrequent. We present the case of a 58-year-old man with a history of diabetes mellitus type 1 who underwent successful pancreas transplantation with bladder drainage. His kidney function failed 13 years after his transplant and he developed recurrent painful hematuria with symptomatic anemia 2 years after initiating hemodialysis. Upon work-up, he was found to have a 4 cm intraductal papillary mucinous neoplasm in his pancreas allograft. At his enteric conversion, the intraductal papillary mucinous neoplasm was removed through a distal pancreatectomy due to concern for its malignant potential. He recovered well from surgery and continues to be insulin-free. With the rising incidence of PNLs from improved detection and the improved survival of pancreas allografts, the implications of PNLs may be more pronounced in the future. This case raises several important considerations for the pancreas transplant surgeon regarding adequate allograft surveillance protocols, treatment, and follow-up.

Multi-Modality Imaging Evaluation of the Whole-Organ Pancreas Transplant

Pancreas transplants are an important treatment options for patients with severe diabetes mellitus and other medical conditions. Multiple-imaging modalities, including computed tomography (CT), magnetic resonance imaging (MRI) and ultrasound (US) are available to evaluate the pancreas transplants and their vascular supply, with the graft having a characteristic appearance on each modality. Complications of the graft and its vascular supply present interesting challenges to the clinicians and radiologists caring for this patient population. Being able to identify the imaging appearance of normal and abnormal pancreas transplants, it is necessary to ensure these patients are provided optimal care.

Neoplasm incidence in simultaneous pancreas and kidney transplantation: a single-center analysis

BACKGROUND

Long-term immunosuppression is associated with an increased rate of cancer. The aim of this study was to analyze the incidence of newly diagnosed tumors in simultaneous kidney and pancreas transplantation (SPKT).

METHODS

We retrospectively analyzed the incidence of a neoplasm among 360 diabetic subjects who consecutively underwent SPKT from 1985 to August 2010 in a single institution. Data were retrieved from the institutional registry. We evaluated the nature of all newly diagnosed malignant tumors, including posttransplantation lymphoproliferative disease (PTLD), to compare Kaplan-Meier survival rates with those of patients free of a neoplasm.

RESULTS

The median follow-up was 8 years; the overall 5-year patient survival was 84%. In 25 patients the tumors were malignant. Almost one-fourth of the cancers represented skin tumors (3 squamous cell and 4 basal cell carcinomas). PTLD was diagnosed in 5 recipients. The cumulative survival of patients with malignancies was significantly lower than that in recipients without cancer (8-year survival by 38% vs 70%; P < .001). The mean (±SD) time to diagnosis was 6 ± 3 years. Since 2004, the 12 recipients with malignancy who were switched to sirolimus at the time of diagnosis showed survivals that were not apparently better than those who remained on the established immunosuppression (46% vs 55%; P = .71).

CONCLUSIONS

The risk of neoplasm development was similar to that reported by other centers. Recipients of SPKT show higher incidence of cancer, though their overall survival is still significantly better than in those usually remaining on dialysis.

Immunosuppression for pancreas transplantation with an emphasis on antibody induction strategies: review and perspective

A review of recent literature was performed to identify trends and evaluate outcomes with respect to immunosuppression in pancreas transplantation (PTX). In the past decade, the majority of PTXs were performed with depleting antibody induction, particularly in the setting of either calcineurin inhibitor minimization, corticosteroid withdrawal or both. Maintenance immunosuppression consisted of predominantly tacrolimus (TAC)/mycophenolatemofetil, TAC/mycophenolic acid or TAC/sirolimus with or without corticosteroids. Depending on PTX category, donor and recipient risk factors, case mix and immunosuppressive regimen, the 1-year incidence of acute rejection has decreased to 5-20%. Current 1-year rates of immunological pancreas graft loss range between 1.8 and 6%. Depleting antibody induction and either TAC/mycophenolatemofetil or TAC/sirolimus maintenance therapy with early steroid withdrawal have become the mainstay of immunosuppression in PTX. However, the development of non-nephrotoxic, nondiabetogenic, and nongastrointestinal toxic regimens is highly desirable to improve quality of life in all solid organ transplant recipients.

Neurologic complications of pancreas and small bowel transplantation

In the past decade, substantial improvements in patient and graft survival for pancreas and small bowel transplants have been achieved. Despite this progress, many patients still develop neurologic complications in the course of their illness. Small bowel transplants produce more neurologic complications because of the complex metabolic environment in which the procedure is performed and because of the intense immune suppression necessitated by the greater immunogenicity of the intestinal mucosa. Pancreas transplants stabilize and/or improve the signs and symptoms of diabetic neuropathy over time. Because transplantation of the pancreas is often coupled with a kidney transplant and small intestine with liver, neurologic complications in these patients sometimes reflect problems involving the organ partner or both organs. The spectrum of neurologic complications for pancreas and small bowel transplant recipients is similar to other organ transplants but their frequency varies depending on the type of transplant performed.

Acute pancreas allograft rejection is associated with increased risk of graft failure in pancreas transplantation

The effect of acute allograft rejection (AR) on long-term pancreas allograft function is unclear. We retrospectively studied 227 consecutive pancreas transplants performed at our institution between January 1, 998 and December 31, 2009 including: 56 simultaneous pancreas and kidney (SPK), 69 pancreas transplantation alone (PTA); and 102 pancreas after kidney (PAK) transplants. With a median follow-up of 6.1 (IQR 3-9) years, 57 patients developed 79 episodes of AR, and 19 experienced more than one episode. The cumulative incidence for AR was 14.7%, 19.7%, 26.6% and 29.1% at 1, 2, 5 and 10 years. PTA transplant (hazards ratio [HR]=2.28, p=0.001) and donor age (per 10 years) (HR=1.34, p=0.006) were associated with higher risk for AR. The first AR episode after 3 months post PT was associated with increased risk for complete loss (CL) (HR 3.79, p<0.001), and the first AR episode occurring during 3- to 12-month and 12- to 24-month periods after PT were associated with significantly increased risk for at least partial loss (PL) (HR 2.84, p=0.014; and HR 6.25, p<0.001, respectively). We conclude that AR is associated with increased risk for CL and at least PL. The time that the first AR is observed may influence subsequent graft failure.

Pancreatic transplant in diabetes

Whole organ pancreas transplantation is increasingly being performed for the treatment of diabetes mellitus. To date, over 32,000 pancreas transplants have been performed worldwide. The procedure is associated with significant mortality and morbidity in early transplant period. However, the successful pancreas transplantation has the potential to render patients insulin-independent and halt the progression of complications of diabetes, thereby improving both quality of life and patient survival.

The Seville expert workshop for progress in posttransplant lymphoproliferative disorders

: Posttransplant lymphoproliferative disorders (PTLDs) are associated with significant morbidity and mortality among solid-organ transplant patients, but approaches to diagnosis and management vary considerably. An international multidisciplinary panel evaluated current understanding of risk factors and classification systems and developed recommendations to aid in PTLD prevention. We considered evidence on PTLD risk factors including Epstein-Barr virus serostatus and immunosuppression and identified knowledge gaps for future research. Recommendations address prophylactic and preemptive strategies to minimize PTLD development, including modulation of immunosuppression and antiviral drug regimens. Finally, new classification criteria were outlined that may help facilitate standardized reporting and improve our understanding of PTLD.

Transplantation of the pancreas

Pancreas transplantation consistently induces insulin-independence in beta-cell-penic diabetic patients, but at the cost of major surgery and life-long immunosuppression. One year after grafting, patient survival rate now exceeds 95 % across recipient categories, while insulin independence is maintained in some 85 % of simultaneous pancreas and kidney recipients and in nearly 80 % of solitary pancreas transplant recipients. The half-life of the pancreas graft currently averages 16.7 years, being the longest among extrarenal grafts, and substantially matching the one of renal grafts from deceased donors. The difference between expected (100 %) and actual insulin-independence rate is mostly explained by technical failure in the postoperative phase, and rejection in the long-term period. Death with a functioning graft remains a further major issue, especially in uremic patients who have undergone prolonged periods of dialysis. Refinements in graft preservation, surgical techniques, immunosuppression, and prophylactic treatments are expected to further improve the results of pancreas transplantation.

Imaging of whole-organ pancreas transplants

Whole pancreas transplantation is an established treatment for selected patients with diabetic nephropathy or poorly controlled diabetes. Surgical techniques vary and have evolved over the past 4 decades. Imaging evaluation of the whole-pancreas transplant should begin with an understanding of the most commonly used surgical techniques and the spectrum of postoperative complications. Ultrasonography (US) should be the first-line modality in evaluating the pancreas allograft and vasculature. Computed tomography (CT) is useful in the assessment of extra-allograft processes, particularly in ruling out abscess formation or evaluating suspected bowel complications. Magnetic resonance (MR) imaging is reserved for cases in which complete evaluation with US or CT is not possible. MR angiography can help provide an accurate assessment of vascular abnormalities. The radiologist must be familiar with the spectrum of surgical techniques and the normal postoperative imaging appearances of the whole-pancreas transplant so as to be able to recognize abnormal postoperative findings. Supplemental material available at http://radiographics.rsna.org/lookup/suppl/doi:10.1148/rg.322115144/-/DC1.

Laparoscopic robot-assisted pancreas transplantation: first world experience

BACKGROUND

Surgical complications are a major disincentive to pancreas transplantation, despite the undisputed benefits of restored insulin independence. The da Vinci surgical system, a computer-assisted electromechanical device, provides the unique opportunity to test whether laparoscopy can reduce the morbidity of pancreas transplantation.

METHODS

Pancreas transplantation was performed by robot-assisted laparoscopy in three patients. The first patient received a pancreas after kidney transplant, the second a simultaneous pancreas kidney transplantation, and the third a pancreas transplant alone. Operations were carried out through an 11-mm optic port, two 8-mm operative ports, and a 7-cm midline incision. The latter was used to introduce the grafts, enable vascular cross-clamping, and create exocrine drainage into the jejunum.

RESULTS

The two solitary pancreas transplants required an operating time of 3 and 5 hr, respectively; the simultaneous pancreas kidney transplantation took 8 hr. Mean warm ischemia time of the pancreas graft was 34 min. All pancreatic transplants functioned immediately, and all recipients became insulin independent. The kidney graft, revascularized after 35 min of warm ischemia, also functioned immediately. No patient had complications during or after surgery. At the longer follow-up of 10, 8, and 6 months, respectively, all recipients are alive with normal graft function.

CONCLUSIONS

We have shown the feasibility of laparoscopic robot-assisted solitary pancreas and simultaneous pancreas and kidney transplantation. If the safety and feasibility of this procedure can be confirmed by larger series, laparoscopic robot-assisted pancreas transplantation could become a new option for diabetic patients needing beta-cell replacement.

Complications following pancreatic transplantations: imaging features

Whole organ vascularized pancreatic transplant is a recognized treatment for diabetes and is increasingly being performed worldwide. The procedure itself is complex and is associated with significant mortality and morbidity. Despite improvements in surgical techniques, postoperative complications of pancreatic transplantation are still common and include graft rejection, pancreatitis, peripancreatic fluid collections, exocrine leaks, vascular thrombosis, and hemorrhage. In this pictorial essay, we review clinical presentation and imaging features of these complications. We also briefly discuss technique and complications of islet cell transplants.

Current perspectives on laparoscopic robot-assisted pancreas and pancreas-kidney transplantation

Pancreas transplant recipients continue to suffer high surgical morbidity. Current robotic technology provides a unique opportunity to test whether laparoscopy can improve the post-operative course of pancreas transplantation (PT). Current knowledge on robotic pancreas and renal transplantation was reviewed to determine feasibility and safety of robotic PT. Information available from literature was included in this review, together with personal experience including three PT, and two renal allotransplants. As of April 2011, the relevant literature provides two case reports on robotic renal transplantation. The author's experience consists of one further renal allotransplantation, two solitary PT, and one simultaneous pancreas-kidney transplantation. Information obtained at international conferences include several other renal allotransplants, but no additional PT. Preliminary data show that PT is feasible laparoscopically under robotic assistance, but raises concerns regarding the effects of increased warm ischemia time on graft viability. Indeed, during construction of vascular anastomoses, graft temperature progressively increases, since maintenance of a stable graft temperature is difficult to achieve laparoscopically. There is no proof that progressive graft warming produces actual damage to transplanted organs, unless exceedingly long. However, this important question is likely to elicit a vibrant discussion in the transplant community.

Reduction of immunosuppression as initial therapy for posttransplantation lymphoproliferative disorder(★)

Reduction of immunosuppression (RI) is commonly used to treat posttransplant lymphoproliferative disorder (PTLD) in solid organ transplant recipients. We investigated the efficacy, safety and predictors of response to RI in adult patients with PTLD. Sixty-seven patients were managed with RI alone and 30 patients were treated with surgical excision followed by adjuvant RI. The response rate to RI alone was 45% (complete response-37%, partial response-8%). The relapse rate in complete responders was 17%. Adjuvant RI resulted in a 27% relapse rate. The acute rejection rate following RI-containing strategies was 32% and a second transplant was feasible without relapse of PTLD. The median survival was 44 months in patients treated with RI alone and 9.5 months in patients who remained on full immunosuppression (p = 0.07). Bulky disease, advanced stage and older age predicted lack of response to RI. Survival analysis demonstrated predictors of poor outcome-age, dyspnea, B symptoms, LDH level, hepatitis C, bone marrow and liver involvement. Patients with none or one of these factors had a 3-year overall survival of 100% and 79%, respectively. These findings support the use of RI alone in low-risk PTLD and suggest factors that predict response and survival.

Immunosuppression in simultaneous pancreas-kidney transplantation: progress to date

Simultaneous pancreas-kidney transplantation (SPKT) is the treatment of choice for patients with end-stage renal failure due to type 1 diabetes mellitus. With advances in surgical techniques and immunosuppression management, outcomes have improved, with current 1- and 10-year pancreas graft survival rates of 86% and 53%, respectively. Induction therapy with either alemtuzumab or rabbit antithymocyte globulin (rATG) in combination with a calcineurin inhibitor (CNI) and mycophenolate mofetil (MMF) or sirolimus appears to be safe and effective in the setting of rapid steroid withdrawal (RSW), with excellent graft survival and low rejection rates. There are no large randomized trials between alemtuzumab and rATG to determine whether one is better than the other. Anti-interleukin (IL)-2 receptor antibody induction and no induction in combination with a CNI, MMF or sirolimus, and prednisone have demonstrated excellent graft survival rates but are associated with a higher incidence of acute rejection. The efficacy of anti-IL-2 receptor antibodies or no induction in the setting of RSW is unproven. Both of the CNIs, ciclosporin and tacrolimus, are effective in preventing acute rejection in SPKT recipients; however, pancreas allograft survival may be better with tacrolimus. MMF is more effective than azathioprine in preventing acute rejection. Sirolimus appears to be effective in preventing acute rejection, but the combination of sirolimus with a CNI may accentuate the nephrotoxicity of the CNI. RSW with induction therapy is safe and effective in SPKT recipients, but longer follow-up data on outcomes are needed. Recent analysis of registry data shows that most transplant centres are using an induction agent followed by a combination of tacrolimus, MMF and corticosteroids in SPKT recipients.

Epidemiology of infections requiring hospitalization during long-term follow-up of pancreas transplantation

BACKGROUND.: Pancreas transplantation (PT) provides the best glycemic control option for diabetes mellitus but is associated with significant morbidities related to infectious disease. METHODS.: We performed a retrospective study of a cohort of consecutive PT recipients in whom PT was performed from 1998 to 2006 (n=216) and followed up them until July 2008. Data regarding infections, rejection, infection chemoprophylaxis, graft failure, absolute lymphocyte counts (ALCs), and mortalities were collected. RESULTS.: Simultaneous pancreas and kidney, pancreas transplantation alone, and pancreas after kidney (PAK) transplantations were performed in 42, 67, and 107 patients, with a mean (standard deviation) age at transplantation of 46.8 (8.03), 40.6 (10.1), and 43.7 (8.19) years. Of the simultaneous pancreas and kidney, pancreas transplantation alone, and PAK transplant recipients, 54.7%, 37.3%, and 58.8% were men. Overall, 63% developed a serious infection during the median follow-up of 6.4 years. Mean (range) number of infectious episodes was 2.3 (1-12), with mostly bacterial infections both within (68%) and after 1 year (78%). Incidence of bacterial and viral infections was greatest in the first 3 months after transplantation. Fungal infections were more constant. Bladder exocrine drainage was associated with higher risk of infection (hazard ratio=2.5, P<0.001). Infection within the first 3 months after transplantation was related to higher mortality after the first 3 months (hazard ratio=3.19). ALC was associated with the risk of first infections (P=0.005) and bacterial infections (P<0.001). CONCLUSIONS.: Incidence of infections after PT was 63% and mostly bacterial. Bladder drainage increases infection risk and low ALC partially predicts episodes. Limitations include retrospective design, unequal composition of PT groups, and lack of data between kidney and PT for PAK.