Use of ultrasound and cystoscopically guided pancreatic allograft biopsies and transabdominal renal allograft biopsies: safety and efficacy in kidney-pancreas transplant recipients

Banff 2022 pancreas transplantation multidisciplinary report: Refinement of guidelines for T cell-mediated rejection, antibody-mediated rejection and islet pathology. Assessment of duodenal cuff biopsies and noninvasive diagnostic methods

The Banff pancreas working schema for diagnosis and grading of rejection is widely used for treatment guidance and risk stratification in centers that perform pancreas allograft biopsies. Since the last update, various studies have provided additional insight regarding the application of the schema and enhanced our understanding of additional clinicopathologic entities. This update aims to clarify terminology and lesion description for T cell-mediated and antibody-mediated allograft rejections, in both active and chronic forms. In addition, morphologic and immunohistochemical tools are described to help distinguish rejection from nonrejection pathologies. For the first time, a clinicopathologic approach to islet pathology in the early and late posttransplant periods is discussed. This update also includes a discussion and recommendations on the utilization of endoscopic duodenal donor cuff biopsies as surrogates for pancreas biopsies in various clinical settings. Finally, an analysis and recommendations on the use of donor-derived cell-free DNA for monitoring pancreas graft recipients are provided. This multidisciplinary effort assesses the current role of pancreas allograft biopsies and offers practical guidelines that can be helpful to pancreas transplant practitioners as well as experienced pathologists and pathologists in training.

Imaging in pancreatic transplants

Pancreatic transplantation, performed alone or in conjunction with kidney transplantation, is an effective treatment for advanced type I diabetes mellitus and select patients with type II diabetes mellitus. Following advancements in surgical technique, postoperative management, and immunosuppression, pancreatic transplantation has significantly improved the length and quality of life for patients suffering from pancreatic dysfunction. While computed tomography (CT) and magnetic resonance imaging (MRI) have more limited utility, ultrasound is the preferred initial imaging modality to evaluate the transplanted pancreas; gray-scale assesses the parenchyma and fluid collections, while Doppler interrogation assesses vascular flow and viability. Ultrasound is also useful to guide percutaneous interventions for the transplanted pancreas. With knowledge of the surgical anatomy and common complications, the abdominal radiologist plays a central role in the perioperative and postoperative evaluation of the transplanted pancreas.

Enteroscopic biopsies in the management of pancreas transplants: a proof of concept study for a novel monitoring tool

BACKGROUND

Although percutaneous biopsies are considered to be the gold standard in diagnosing pancreas graft rejection, they are not performed routinely because of their association with severe complications. On the other hand, correct diagnosis of rejection is essential but may be difficult in cases of enteric drainage, particularly in patients with a pancreas transplant alone or a pancreas after kidney transplant.

METHODS

Pancreas recipients who underwent enteroscopy between May 2005 and September 2009 were included in this retrospective analysis. Biopsies were graded 0 to 4 for interstitial and vascular changes.

RESULTS

During the study period a total of 65 simultaneous pancreas-kidney transplants, 13 pancreas after kidney transplants and 4 pancreas transplants alone were performed. Sixty-three patients underwent a single enteroscopy, 10 had two, and 6 had three or more. Indications were protocol graft monitoring (n=73), graft dysfunction (n=17), enteric hemorrhage (n=9), or other (n=3). The duodenal segment was accessed in 76 instances (75%) with abnormal findings in 23. A total of 69 biopsies were obtained and revealed normal mucosa in 49 cases (71%). Histology showed signs of acute rejection in 11 cases. The upper gastrointestinal tract was also assessed, and, in 13 cases, additional pathologies were identified including gastroduodenitis (n=10), gastric/duodenal ulcer (n=2), and hemorrhagic esophagitis (n=1). No procedure-related complication occurred.

CONCLUSIONS

This series of enteroscopies demonstrates that the duodenal segment of a pancreatic graft is accessible using our implant technique, and thus permitting biopsies to be obtained and endoscopic interventions to be performed.

Duodenoduodenostomy in pancreas transplantation

Enteric drainage (ED) using duodenojejunostomy (DJ) is an established technique in pancreatic transplantation. Duodenoduodenostomy (DD), an alternative ED technique, may provide unique advantages over DJ. We compared our experience with these two types of ED through a retrospective review of all pancreas transplants performed at our institution from November 2007 to November 2009. The allograft duodenum was anastomosed to the recipient jejunum or duodenum. Duodenal drainage was performed by a stapled or hand-sewn technique. Patient demographics, operative times, major post-operative complications, and graft survival data were analyzed. Of 57 pancreas transplants, DJ was performed in 36 patients, stapled DD in 14 patients, and hand-sewn DD in seven patients. Two DD grafts (9.5%) thrombosed compared with no DJ grafts (p = NS). Enteric leak and small-bowel obstruction occurred in 3 of 36 DJ patients and in two DD patients (p = NS). Gastrointestinal bleeding occurred more frequently in stapled DD compared with DJ (4 vs. 0, p < 0.015). In conclusion, DD is technically feasible with no increase in operative time or enteric complications. GI bleeding rates appear to be higher following DD (stapled) technique. Potential complications of DD should be balanced against the benefits conferred by this technique.

Alemtuzumab induction and steroid-free maintenance immunosuppression in pancreas transplantation

Alemtuzumab is a humanized anti-CD52 antibody that depletes lymphocytes and has been increasingly used as induction agent in transplantation. The impact of alemtuzumab induction immunosuppression in pancreas transplantation was evaluated, with particular reference to steroid avoidance in maintenance. A total of 100 patients who received 102 pancreas transplants (83 simultaneous kidney-pancreas [SPK], 15 pancreas after kidney transplantation [PAK] and 4 pancreas transplant alone [PTA]) were included. All patients received two doses of 30-mg alemtuzumab i.v. with tacrolimus (trough level 8-12 ng/mL) and mycophenolate mofetil (MMF,1g/day) with no maintenance steroids. This analysis included 62 male and 38 female recipients, with mean (+/-SD) age of 42 (+/-7.6) years. Median follow-up was 17 months (range 8-41 months). One-year patient, pancreas and kidney graft survival (actuarial) was 97%, 89% and 94%, respectively. Overall incidence of rejection was 25%. Side effects of alemtuzumab administration included thrombocytopenia (14%), pulmonary edema (2%) and rash (1%). Twenty-five percent required reoperations (12% for bleeding). Infectious complications included Cytomegalovirus (CMV,6.8%) BK viruria (3.8%), fungal infections (4%), primary varicella (1%) and posttransplant lymphoproliferative disorders (PTLD,1%). Eighty-three percent did not require any steroids posttransplant. These results indicate that alemtuzumab is safe and enables pancreas transplantation to be carried out without maintenance steroids in 83% of cases and acceptable rejection rate.

Banff schema for grading pancreas allograft rejection: working proposal by a multi-disciplinary international consensus panel

Accurate diagnosis and grading of rejection and other pathological processes are of paramount importance to guide therapeutic interventions in patients with pancreas allograft dysfunction. A multi-disciplinary panel of pathologists, surgeons and nephrologists was convened for the purpose of developing a consensus document delineating the histopathological features for diagnosis and grading of rejection in pancreas transplant biopsies. Based on the available published data and the collective experience, criteria for the diagnosis of acute cell-mediated allograft rejection (ACMR) were established. Three severity grades (I/mild, II/moderate and III/severe) were defined based on lesions known to be more or less responsive to treatment and associated with better- or worse-graft outcomes, respectively. The features of chronic rejection/graft sclerosis were reassessed, and three histological stages were established. Tentative criteria for the diagnosis of antibody-mediated rejection were also characterized, in anticipation of future studies that ought to provide more information on this process. Criteria for needle core biopsy adequacy and guidelines for pathology reporting were also defined. The availability of a simple, reproducible, clinically relevant and internationally accepted schema for grading rejection should improve the level of diagnostic accuracy and facilitate communication between all parties involved in the care of pancreas transplant recipients.

Pancreas graft drainage in recipient duodenum: preliminary experience

Pancreas graft survival has continuously improved over the years to become a main treatment option of uncontrolled complicated diabetes. Rejection remains the major challenge as it often goes unnoticed until severe damage of the graft manifests itself by elevated blood sugar. Pancreas enzymes monitoring in the blood and in the urine is a sensitive marker of rejection but lack of specificity. Biopsy remains the gold standard. Cystoscopy-guided biopsy of bladder-drained pancreas has a good success rate for obtaining tissue but the vesical drainage exposes to metabolic and urologic morbidity. Percutaneous pancreas biopsy can be performed with a low morbidity rate but severe complications can occur. We discuss a technique of pancreas transplantation with the drainage of exocrine secretions of the pancreatic graft in the recipient duodenum, which permits easy monitoring of the graft by upper endoscopy of the duodenum.

Outcomes with the selective use of enteric exocrine drainage in pancreas transplantation

BACKGROUND

Bladder drainage of the exocrine secretions of pancreas transplants has been the standard of practice as it affords the ability to monitor for rejection and is thought to be associated with decreased morbidity. Recently, there has been renewed interest in avoiding the urinary tract complications and metabolic derangements that accompany bladder drainage by draining pancreatic exocrine secretions into the jejunum (enteric drainage). We sought to determine whether enteric drainage of pancreas transplants is safe and offers advantages without compromise in graft function or longevity.

METHODS

We retrospectively reviewed all pancreas transplants performed at the University of Washington between 2000 and 2003. Selection of the exocrine drainage method was based on the length of cold ischemia time and whether the pancreas was transplanted alone or in combination with a kidney. Pearson's chi-square and Fisher's Exact tests were used for statistical comparisons in complications or rejections between the groups.

RESULTS

Thirty-four pancreas transplants were performed with exocrine drainage into the bladder used in 17 and enteric drainage in 17. The complication rate was 53% in the bladder-drained group and 41% (P=.49) in the enteric-drained group. The incidence of pancreas rejection was 24% in the bladder-drained versus 29% in the enteric-drained patients (P=.50). One graft failed, which was in the bladder cohort.

CONCLUSIONS

We found comparable rejection and complication rates between groups. We conclude that enteric drainage is safe when used selectively, and entails no increased risks compared with bladder drainage.

Role of sonography in pancreatic transplantation

Despite recent advancements in surgical technique and immunosuppressive therapy, postoperative complications of pancreatic transplantation are still common. A complex spectrum of such adverse events includes graft rejection, peripancreatic fluid collections, pancreatitis, exocrine leaks, vascular thrombosis, and hemorrhage. Sonography plays a key role in the initial evaluation of the transplanted pancreas. Gray-scale sonography, duplex Doppler imaging, and sonographic guidance for percutaneous biopsy all contribute to posttransplantation evaluation and detection of sequelae. Color and power Doppler imaging offer valuable information regarding the regional vasculature and potential vascular complications. Because gray-scale sonographic findings alone are often nonspecific, several clinical criteria, including those from biochemical analysis of the urine and serum, must be reviewed with the sonographic findings to provide a thorough evaluation of the transplanted pancreas. When used in conjunction with serologic and urinary markers, the findings from sonography can help direct management options or suggest the need for further examination. Therefore, an understanding of the spectrum of complications combined with knowledge concerning the limitations of this imaging modality are essential for proper diagnosis and effective treatment.

Evaluation of pancreatic allograft dysfunction by laparoscopic biopsy

BACKGROUND

Histologic evaluation of a failing pancreatic allograft is necessary for accurate classification of graft dysfunction. Unlike percutaneous or transcystoscopic techniques, laparoscopic biopsy allows visualization of the allograft in addition to obtaining tissue for histologic examination.

METHODS

We retrospectively reviewed all laparoscopic pancreas transplant biopsies performed over a 15-month period ending February 2002.

RESULTS

There were 12 laparoscopic pancreas biopsies performed in 11 patients between 6 weeks and 8 years (mean 2.5+/-2.8 years) after transplant. Indications for biopsy were hyperglycemia (n=8), hyperamylasemia (n=3), and graft tenderness (n=1). Adequate tissue was obtained in 11 of 12 biopsies. Two patients received definitive treatment at the time of laparoscopy (pseudocyst debridement, ovarian cyst excision).

CONCLUSIONS

Laparoscopic pancreas transplant biopsy allows safe visualization of the allograft and effective specimen retrieval, and in some cases provides the opportunity for therapeutic intervention.

Urologic aspects of kidney-pancreas transplantation

The population of pancreas transplant recipients is growing steadily, and urologists most likely will be confronted with their unique anatomy and metabolic complications. The principles of diagnosis and management of these patients can be applied to other transplant recipients (e.g., heart, lung, and liver) who also are maintained on life-long immunosuppression and in whom urologic pathology develops commensurate with the incidence in the general population.

Trends and perspectives in pancreas and simultaneous pancreas and kidney transplantation

Pancreas transplantation is still the best option to achieve normoglycaemia and insulin independence in patients with type I diabetes. As a result of improvements in surgical techniques, immunosuppression and patient selection, one year survival rates of 95, 83, and 88% for patient, pancreas, and kidney survival, respectively, are reported for patients with simultaneous pancreas and kidney transplantation. The main goals for the future are to reduce postoperative morbidity, to identify the relevant indications for single pancreas transplantation, to adopt the best surgical technique for individual patients' needs (bladder versus enteric drainage with or without portal venous delivery of insulin), and to develop immunosuppressive strategies with low nephrotoxic and diabetogenic potential.

The role of percutaneous biopsy in detection of pancreatic transplant rejection

The purpose of this study was to investigate the effectiveness and safety of percutaneous pancreatic transplant biopsy guided by ultrasound alone or with a combination of computerized tomography (CT) for pancreas localization and ultrasound for needle placement. We also compare our finding on the use of 18-gauge and 20-gauge needles for percutaneous pancreatic transplant biopsy. In 42 attempted biopsies performed on 21 patients, two different imaging modalities were used. Twenty-seven attempted biopsies were performed under the guidance of ultrasound alone, and 15 used a combination of ultrasound and CT. Of the 27 ultrasound-guided biopsies. 24 produced at least one sample adequate for histopathological analysis for an 89% biopsy success rate. Of the 15 biopsies guided by combined ultrasound and CT, 11 produced adequate samples for a 73% success rate. For all biopsies, an 83% success rate was found. In assessing the use of 18-gauge versus 20-gauge needles, 86 out of 110 tissue cores were adequate for histopathological analysis for a 78% yield. In 27 biopsy attempts using the 18-gauge needle, 75 tissue cores were obtained, for an average of 2.8 cores per biopsy. Fifty-seven pancreas samples collected using the 18-gauge needle were adequate for pathological evaluation for a 76% yield. With 15 biopsy attempts using the 20-gauge needle, 35 tissue cores were collected, for an average of 2.3 cores per biopsy. Twenty-nine pancreas specimens obtained from using the 20-gauge needle were adequate for analysis for an 83% yield. No major complications occurred. Only one incidence of minor complication was reported for a 2% complication rate. The only complication was local, mild bleeding at the biopsy site in one case. Air within the transplant pancreas as revealed by post-biopsy scans and streaky density appearing adjacent to the biopsy site occurred in a total of four cases and were not included. No complications were reported that required any invasive intervention. We conclude that percutaneous biopsy guided by ultrasound is a safe, simple, and effective method to detect pancreatic transplant rejection. Our results for biopsies compare favorably with other reported techniques in terms of effectiveness, complication rates, and ease of use. With its high success rate and low complications, ultrasound-guided percutaneous biopsy is an excellent method to sample pancreatic transplant.

Acute pancreatic transplant rejection: evaluation with dynamic contrast-enhanced MR imaging compared with histopathologic analysis

PURPOSE

To evaluate the use of dynamic contrast material-enhanced gradient-recalled-echo MR imaging for the diagnosis of acute pancreatic transplant rejection, as confirmed at histopathologic analysis.

MATERIALS AND METHODS

Thirty MR imaging studies were performed in 25 patients within 3 days of percutaneous biopsy or pancreatectomy. The mean percentage of parenchymal enhancement (MPPE) at dynamic contrast-enhanced MR imaging was calculated.

RESULTS

Biopsy findings were no evidence of rejection (n = 7 [23%]), mild rejection (n = 10 [33%]), moderate (n = 6 [20%]) and severe (n = 2 [7%]) acute rejection, and infarction (n = 5 [17%]). The corresponding MPPEs at 1 minute were 106%, 66%, 62%, 57%, and 3%, respectively. Overlap of cases in the normal and rejection groups occurred; however, using an MPPE cutoff of 100% resulted in a sensitivity of 96%. An MPPE over 120% was seen in the normal group only. The MPPE was significantly greater in the normal group than in the rejection or infarction group (P < .05).

CONCLUSION

Dynamic contrast-enhanced MR imaging is highly sensitive for the detection of acute pancreatic transplant rejection. Because of overlap of cases in the normal and rejection groups, percutaneous biopsy may be needed in some cases. Pancreatic allografts with infarction can be clearly identified.

Urological complications of pancreatic transplantation

PURPOSE

Pancreas transplantation is increasingly being used in the treatment of type I insulin-dependent diabetes mellitus. Because bladder drainage of the exocrine pancreatic secretion is the procedure of choice, urological complications are frequent. As the number of these procedures increases the urologist will have an extended role in the management of the postoperative complications, the majority of which are urological.

MATERIALS AND METHODS

The literature from 1985 on the complications related to pancreas transplants was reviewed.

RESULTS

Approximately 50 to 60% of bladder drained pancreas transplant recipients will have a urological complication postoperatively.

CONCLUSIONS

The increasing application of bladder drained pancreas transplantation in the treatment of type I insulin-dependent diabetes mellitus necessitates that the clinical urologist is familiar with the management of complications related to this procedure.

Equivalent success of simultaneous pancreas kidney and solitary pancreas transplantation. A prospective trial of tacrolimus immunosuppression with percutaneous biopsy

OBJECTIVE

This study was designed to evaluate the results of solitary pancreas transplantation in a protocol that uses the new immunosuppressant tacrolimus (FK) and liberally applies ultrasound-guided percutaneous pancreas biopsy to diagnose rejection.

SUMMARY BACKGROUND DATA

Pancreas graft survival in patients who simultaneously receive a kidney transplant (SPK) historically has been 75% to 90% at 1 year, approaching that of cadaveric kidney transplantations. In sharp contrast, graft survival rates in patients who receive a pancreas atone (PA) have remained static over the past decade, with approximately 50% functional at 1 year. It was hypothesized that the results of PA transplantations would improve with newer maintenance immunosuppressants and biopsy techniques.

METHODS

Twenty-seven PA recipients prospectively were treated with FK-based immunosuppression (PA-FK). Percutaneous biopsy was performed for hyperamylasemia, hyperlipasemia, hypoamylasuria, or unexplained fever. One year pancreas graft survival in these patients was compared to 15 cyclosporine treated PA cases (PA-CsA) and 113 SPK recipients.

RESULTS

The 1-year pancreas graft survival rate of 90.1% in technically successful PA-FK patients was significantly better than the 53.4% rate in PA-CsA recipients (p = 0.002) and no different than the 87.4% rate in SPK recipients. The only graft lost to acute rejection in the PA-FK group was because of acknowledged patient noncompliance. Percutaneous biopsy substantially improved the diagnostic certainty in cases of suspected rejection and was associated with a low complication rate (3/178 = 1.5%).

CONCLUSIONS

Modern immunosuppression and biopsy techniques have improved the success of solitary pancreas transplantations to the point where outcome is now equivalent to that of SPKs.