Pancreas Transplants: Experience with 232 Percutaneous US-guided Biopsy Procedures in 88 Patients

An Initial Analysis of the Baseline Levels of Dd-cfDNA After Pancreas Transplantation: A Prospective Study From High-volume Centers in the United States

Pancreas transplantation offers patients with diabetes an opportunity for glucose homeostasis. Current blood tests to surveil for rejection have poor sensitivity and specificity for identifying rejection, and pancreas biopsies are challenging and associated with morbidity and graft loss. Donor-derived cell-free DNA (dd-cfDNA) is shed from transplanted organs and detectable in peripheral blood. Thus, a potential dd-cfDNA blood test assessing rejection would be clinically advantageous.

Methods

One hundred eighty-one dd-cfDNA samples (n) were collected from 77 patients (N) up to 132 mo posttransplant.

Results

The median dd-cfDNA level among all subjects was 0.28% (0.13%, 0.71%). In simultaneous pancreas-kidney (SPK) transplant recipients, the median dd-cfDNA level was 0.29% (0.13%, 0.71%), and it was 0.23% (0.08%, 0.71%) in pancreas transplant alone (PTA) recipients. When isolating for when without infection or rejection, the median dd-cfDNA level was 0.28% (0.13%, 0.64%) for SPK and 0.20% (0.00%, 0.32%) for PTA. Both transplant types approached 1.0% ≤1 mo posttransplant followed by a decrease in median dd-cfDNA. During episodes of rejection or infection, median dd-cfDNA levels were greater among all transplant types.

Conclusions

The mean dd-cfDNA level for all pancreas transplant recipients is <1.0%, consistent with the published kidney transplant rejection threshold (>1.0%), regardless of SPK or PTA. Early posttransplant dd-cfDNA levels are transiently higher than later measurements. Dd-cfDNA elevation also correlates with rejection and infection and thus is a promising biomarker for surveilling pancreas transplant dysfunction.

Endoscopic visualization of graft status in patients with pancreas transplantation

BACKGROUND

Enteric drainage into the recipient duodenum in pancreas transplantation (PT) can identify the graft duodenum by endoscopy. This study aimed to identify the characteristic endoscopic findings associated with graft failure or acute rejection in patients with PT.

METHODS

We reviewed the medical records of patients who underwent PT with duodenoduodenostomy (DD) between January 2015 and August 2019. During this period, there were 44 PTs with DD in 42 patients; 122 endoscopies were performed and analyzed.

RESULTS

Overall, pancreatic graft survival was 82% at a mean follow-up of 27 months (range 6-55 months). There were 8 graft failures and 10 acute rejections. In all 8 graft failures, a deep ulcer covered with fibrinous exudates of the graft duodenum was confirmed on endoscopy. Diffuse erythema inside the graft duodenum was observed in 8 of 10 acute rejections. The factors associated with acute rejection were elevated serum lipase level (OR 8.5, p = 0.02) and diffuse erythema inside the graft duodenum on endoscopy (OR 20.5, p < 0.01) in multivariate analysis.

CONCLUSIONS

In PT with DD patients, graft failure can be visualized by endoscopy, and diffuse erythema inside the graft duodenum may be a finding of acute rejection.

Percutaneous biopsy and drainage of the pancreas

Percutaneous pancreatic interventions performed by abdominal radiologists play important diagnostic and therapeutic roles in the management of a wide range of pancreatic pathology. While often performed with endoscopy, pancreatic mass biopsy obtained via a percutaneous approach may serve as the only feasible option for diagnosis in patients with post-surgical anatomy, severe cardiopulmonary conditions, or prior non-diagnostic endoscopic attempts. Biopsy of pancreatic transplants are commonly performed percutaneously due to inaccessible location of the allograft by endoscopy, usually in the right lower quadrant or pelvis. Percutaneous drainage of collections in acute pancreatitis is primarily indicated for infection with clinical deterioration and may be performed alone or in combination with endoscopic drainage. Post-surgical pancreatic collections related to pancreatic duct fistula or leak also often warrant therapeutic percutaneous drainage. Knowledge of appropriate indications, strategies of approach, technique, and complications associated with these procedures is critical for a successful clinical practice.

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.

Evaluation of circulating tumor cell clusters for pan-cancer noninvasive diagnostic triaging

BACKGROUND

Histopathologic examination (HPE) of tumor tissue obtained by invasive biopsy is the standard for cancer diagnosis but is resource-intensive and has been associated with procedural risks. The authors demonstrate that immunocytochemistry (ICC) profiling of circulating ensembles of tumor-associated cells (C-ETACs) can noninvasively provide diagnostic guidance in solid organ cancers.

METHODS

The clinical performance of this approach was tested on blood samples from 30,060 individuals, including 9416 individuals with known cancer; 6725 symptomatic individuals with suspected cancer; and 13,919 asymptomatic individuals with no prior diagnosis of cancer. C-ETACs were harvested from peripheral blood and profiled by ICC for organ-specific and subtype-specific markers relevant to the cancer type. ICC profiles were compared with HPE diagnoses to determine concordance.

RESULTS

The presence of malignancy was confirmed by the detection of C-ETACs in 91.8% of the 9416 individuals with previously known cancer. Of the 6725 symptomatic individuals, 6025 were diagnosed with cancer, and 700 were diagnosed with benign conditions; C-ETACs were detected in 92.6% of samples from the 6025 individuals with cancer. In a subset of 3509 samples, ICC profiling of C-ETACs for organ-specific and subtype-specific markers was concordant with HPE findings in 93.1% of cases. C-ETACs were undetectable in 95% of samples from the 700 symptomatic individuals who had benign conditions and in 96.3% of samples from the 13,919 asymptomatic individuals.

CONCLUSIONS

C-ETACs were ubiquitous (>90%) in various cancers and provided diagnostically relevant information in the majority (>90%) of cases. This is the first comprehensive report on the feasibility of ICC profiling of C-ETACs to provide pan-cancer diagnostic guidance with accuracy comparable to that of HPE.

Association of aspirin and other non-steroidal anti-inflammatory drugs with bleeding complications in image-guided musculoskeletal biopsies

OBJECTIVE

To evaluate the safety of continuing aspirin and other non-steroidal anti-inflammatory drugs (NSAID) in patients undergoing image-guided musculoskeletal biopsies.

MATERIAL AND METHODS

Prior to October 2017, patients undergoing image-guided musculoskeletal biopsy had aspirin and NSAIDs withheld for the preceding 5-7 days. The policy changed in October 2017 based on new guidelines from the Society of Interventional Radiology such that aspirin and other NSAIDs were not withheld. A retrospective review of patient records was performed for all biopsies prior to and after the policy change to assess for differences in biopsy-related bleeding complications. Additional clinical and biopsy factors including age, gender, liver disease, coagulopathy, biopsy tissue type, and histological diagnosis were assessed.

RESULTS

In the pre-policy change group, there were 1853 total biopsies with 43 biopsy-related bleeding complications (2.3%). Within this group, 362 patients were on aspirin with 7 bleeding complications (1.9%) and 260 patients were on NSAIDs with 5 bleeding complications (1.9%). There were 409 total biopsies in the post-policy change group and 7 bleeding complications (1.7%). Within this group, 71 patients were on aspirin with 1 bleeding complication (1.4%). No bleeding complications were recorded in patients on NSAIDs (0%). There was no significant difference in bleeding complication between the pre- and post-policy change groups overall (p = 0.58) and in patients on aspirin (p = 1.00) or other NSAIDs (p = 1.00).

CONCLUSION

Bleeding complications for musculoskeletal biopsies are rare. Leaving patients on aspirin or other NSAIDs during a musculoskeletal biopsy does not increase the incidence of bleeding complications.

Management of vascular and nonvascular complications following pancreas transplantation with interventional radiology

Pancreas transplantation exposes to high rates of complications, either vascular (thrombosis, stenosis, pseudoaneurysm, arteriovenous fistula) or nonvascular (fluid collection, graft rejection). With advances in percutaneous and endovascular techniques, interventional radiologists are increasingly involved in the management of these complications. In this article, we review the anatomical considerations relevant to pancreas transplantation, the techniques used for image-guided interventions for vascular and nonvascular complications, and the expected outcomes of these interventions.

Complication incidence of EUS-guided pancreas biopsy: A systematic review and meta-analysis of 11 thousand population from 78 cohort studies

A systematic review and meta-analysis were performed to estimate the incidence of possible complications following EUS-guided pancreas biopsy. Pancreatic cancer has a very poor prognosis with a high fatality rate. Early diagnosis is important to improve the prognosis of pancreatic cancer. We searched Pubmed, Embase, Web of Science, and Scopus databases for studies published from inception to Augest, 2018. Meta-analysis were conducted with random-effect models and heterogeneity was calculated with the Q, I² and τ² statistics. We enrolled 78 studies from 71 articles in the meta-analysis, comprising 11,652 patients. Pooled data showed that the whole complication incidences were low 0.210 × 10^-4(95%CI -0.648 × 10^-4, 1.068 × 10^-4). And they were in bleeding 0.002 × 10^-4 (95%CI -0.092 × 10^-4, 0.097 × 10^-4), pancreatitis 0.002 (95%CI -0.082 × 10^-4, 0.086 × 10^-4), abdominal pain 0 (95%CI -0.037 × 10^-4, 0.038 × 10^-4), fever 0 (95%CI -0.032 × 10^-4, 0. 032 × 10^-4), infection 0 (95%CI -0.030 × 10^-4, 0.031 × 10^-4), duodenal perforation 0 (95%CI -0.033 × 10^-4, 0.034 × 10^-4), pancreatic fistula 0 (95%CI -0.029 × 10^-4, 0.029 × 10^-4), abscess 0 (95%CI -0.029 × 10^-4, 0.029 × 10^-4) and sepsis 0 (95%CI -0.029 × 10^-4, 0.030 × 10^-4). Subgroup analysis based on the tumor size, site, needle type and tumor style also showed robust results. The pooled data showed EUS-guided pancreas biopsy could be a safe approach for the diagnosis of pancreatic lesions. More large-scale studies will be necessary to confirm the findings across different population.

Gray-scale, Doppler and contrast-enhanced ultrasound in pancreatic allograft surveillance: A systematic literature review

BACKGROUND

Gray scale ultrasound (US), Doppler and Contrast Enhanced Ultrasound (CEUS) represent important surveillance tools in the early post-operative period after pancreas transplantation (PTx), when complications are more common. This review summarizes the available evidence on their clinical application in this setting.

METHODS

We searched the Pub-Med database from inception to October 2018 for English literature on the clinical use of US, Doppler and CEUS in the post-PTx surveillance. Article selection was carried out according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses criteria (PRISMA).

RESULTS

Twenty-nine articles concerning the clinical applications of US, Doppler and CEUS were identified, 13 of which, involving 264 patients, were focused on the sonographic findings in immunologic rejection, whereas 11 studies reporting on 887 patients were focused on post-PTx vascular complications. The remaining five articles, involving a total of 196 patients, described US or CEUS applied in the study of pancreatic morphology and texture to diagnose peri-graft fluids collections or to obtain experimental data on allograft endocrine function.

CONCLUSIONS

US, Doppler and CEUS have proven to be valuable assets in post-PTx follow up, thanks to the combination of their non-invasiveness with a high accuracy in the detection of early abnormalities, in particular regarding vascular complications. Preliminary experiences are directing towards functional research; however, future prospective trials are necessary to precisely correlate organ perfusion, early abnormalities and allograft function.

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.

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.

Ultrasound-Guided Percutaneous Core Needle Biopsy for the Diagnosis of Pancreatic Disease

Few studies have evaluated the performance of percutaneous core needle biopsies of the pancreas. This article is an overview of the advantages, disadvantages, predictive power and complications associated with percutaneous ultrasound-guided core needle biopsies of pancreatic lesions. A comprehensive literature search of Medline (using PubMed as the search engine) and EMBASE was done to identify suitable studies up to March 2017. A study of quantitative pre-operative pancreatic biopsy data was reported. Lesion location, mean or median number of passes, inadequate tissue or technical failures and complications were assessed for all cases by reviewing clinical notes and post-procedural imaging. The analysis included 13 studies, mostly of a retrospective nature. The sensitivity (mean: 94.42%, range: 90%-100%) and specificity (mean: 97.94%, range: 94.7%-100%) of the procedure were high, and the mean accuracy of diagnosis was 95.76 (range: 91-100). Furthermore, the procedure had a high negative predictive value of approximately 76.26%. Of the 13 reported studies, 7.3% were inadequate or technical failure cases. The mean rate of complications was 2.08%, which seemed similar to the lower limit of this rate for endoscopic ultrasound-guided fine-needle aspirations. The risk of tumor seeding with ultrasound-guided core needle biopsies was not reported in the included articles. With the development of technology, ultrasound-guided percutaneous core needle biopsy for pancreatic lesions is increasingly available and has optimal diagnostic power in pancreatic neoplasms.

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.

Imaging of Pancreas Transplantation and Its Complications

Whole pancreas transplantation is an effective treatment for obtaining euglycemic status in patients with insulin-dependent diabetes mellitus, and is usually performed concurrent with renal transplantation in the affected patient. This article discusses complex surgical anatomical details of pancreas transplantation including surgical options for endocrine and exocrine drainage pathways. It then describes several possible complications related to surgical factors in the immediate post operative period followed by other complications related to systemic issues, vasculature, and the pancreatic parenchyma.

A Single-center Experience on the Value of Pancreas Graft Biopsies and HLA Antibody Monitoring After Simultaneous Pancreas-Kidney Transplantation

BACKGROUND

In simultaneous pancreas-kidney transplantation (SPKT), monitoring of the pancreas allograft is more complex than the kidney allograft due to difficulties in obtaining pancreas histology and weak clinical evidence supporting the role of donor-specific antibodies (DSA).

METHODS

We performed a single-center retrospective analysis of all 17 SPKT recipients who underwent a total of 22 pancreas allograft indication biopsies from October 2009 to September 2012. Fifteen patients had at least 2 DSA measurements: pretransplantation and at the time of biopsy.

RESULTS

All 7 patients (100%) with post-transplantation DSA-positivity (de novo: n = 6; persistent: n = 1) at biopsy had at least 1 rejection episode either of the pancreas (n = 4) or the kidney (n = 3), with 3 antibody-mediated rejections (AMR). In contrast, only 4 of 8 patients (50%) without post-transplantation DSA had evidence of rejection, with 1 AMR. Findings during pancreas allograft biopsy procedures led to a change of immunosuppressive therapy in 11 of 15 (73%) patients. Patient survival, graft survival, and function were not adversely affected by the presence of post-transplantation DSA. One major and 2 minor procedure-related complications occurred during the pancreas biopsies.

CONCLUSIONS

In this small retrospective analysis, pancreas allograft histology provided the most therapeutically relevant information, rather than the kidney histology or DSA monitoring.

Pancreas transplant imaging: how I do it

Pancreas transplantation aims to restore physiologic normoglycemia in diabetic patients with glomerulopathy and avoid or delay the onset of diabetic retinopathy and arteriopathy. Simultaneous pancreas-kidney transplant is the most common approach, using a cadaveric pancreas donation in conjunction with either cadaveric or live donor renal transplant. Alternative techniques include pancreas after kidney transplant, in which the pancreas transplant is performed some years after renal transplant. Pancreas transplant alone is utilized rarely in diabetic patients with compensated renal function. Pancreas grafts have vascular and enteric connections that vary in their anatomic approach, and understanding of this is critical for imaging with ultrasonography, computed tomography, or magnetic resonance imaging. Imaging techniques are directed to display the pancreatic transplant arterial and venous vasculature, parenchyma, and intestinal drainage pathway. Critical vascular information includes venous thrombosis (partial or complete), arterial occlusion, or aneurysm. Parenchymal abnormalities are nonspecific and occur in pancreatitis, graft rejection, and subsequent graft ischemia. Peripancreatic fluid collections include hematoma/seroma, pseudocyst, and abscess. The latter two are related to pancreatitis, duct disruption, or leak from the duodenojejunostomy. An understanding of transplant anatomy and complications will lead to appropriate use of imaging techniques to diagnose or exclude important complications.

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.

Imaging spectrum after pancreas transplantation with enteric drainage

Since the introduction of pancreas transplantation more than 40 years ago, surgical techniques and immunosuppressive regiments have improved and both have contributed to increase the number and success rate of this procedure. However, graft survival corresponds to early diagnosis of organ-related complications. Thus, knowledge of the transplantation procedure and postoperative image anatomy are basic requirements for radiologists. In this article, we demonstrate the imaging spectrum of pancreas transplantation with enteric exocrine drainage.

Pancreas transplantation, antibodies and rejection: where do we stand?

PURPOSE OF REVIEW

Antibody-mediated rejection (AMR) is acknowledged and defined in kidney transplantation, but where do we stand as far as pancreas transplantation is concerned? Here we appraise the most recent findings in pancreatic AMR and give suggestions for future research in the field by addressing currently unresolved issues.

RECENT FINDINGS

Five main topics are discussed: chronological assessment of all literature on biopsy-proven pancreatic AMR; role of C4d and recent development in other markers; the use of sentinel organs, such as kidney biopsies and duodenal patch biopsies for diagnosis of pancreatic AMR; studies addressing islet pathology and its relevance in AMR; and protocol and follow-up pancreas biopsy practice in relation to pancreas transplant management and survival.

SUMMARY

Antibody-mediated processes play a role in pancreas transplantation. However, sensitive markers, pathophysiological understanding, and adequate interventions have not yet been established. Much data are still lacking and we believe that studying protocol and follow-up biopsies along with serial donor-specific antibody data may improve pancreas transplant patient management and outcomes.

Sonographically guided puncture of the pancreas: incidence of complications, and risk factors

PURPOSE

Data yielded by transabdominal ultrasound-guided puncture techniques are valuable for determining the malignancy of inoperable mass lesions of the pancreas. In this study we analyzed the incidence of complications and the risk factors.

METHODS

A total of 430 punctures of the pancreas were performed for 281 patients. Risk factors were prospectively assessed and complications were recorded. All punctures were sonographically guided.

RESULTS

The 281 patients underwent a total of 351 puncture procedures including 430 punctures and 901 passes. The maximum diameter of the pancreatic mass lesion was documented; the mean diameter was 48.3 ± 29.1 mm. 75.8 % of punctures were performed with a needle diameter of 0.7-0.95 mm, and 23.0 % of punctures were performed as cutting biopsies producing a tissue sample 1.2 or 1.6 mm in diameter. In 77.8 % of punctures, one puncture was performed, and in 21.9 %, two punctures were performed. Three punctures were performed for one patient (0.3 %) only. The incidence of major complications was 0.3 %. None of the assessed risk factors was associated with an elevated incidence of complications.

CONCLUSION

Our findings demonstrate the safety of transabdominal percutaneous puncture of the pancreas but do not enable conclusions to be drawn with regard to individual risk factors.

Evaluation of pancreatic allografts with sonography

OBJECTIVES

The purposes of this study were to develop a protocol for evaluating pancreas allografts, to describe a method for successfully studying pancreatic transplants, and to determine whether the resistive index (RI) of the splenic artery is a useful differentiator between complications.

METHODS

We retrospectively analyzed clinical, surgical, procedural, and radiologic reports in 51 consecutive patients undergoing 182 sonographic examinations during a 4.5-year period. Complications included splenic vein thrombosis, rejection, and pancreatitis. We obtained RIs in normal and complication groups and performed mixed model regression methods and receiver operating characteristic analysis.

RESULTS

The mean RI ± SD for normal transplants was 0.65 ± 0.09; for splenic vein thrombosis, 0.76 ± 0.09; after resolution of splenic vein thrombosis, 0.73 ± 0.09; during rejection, 0.94 ± 0.09; after successful treatment of rejection, 0.74 ± 0.09; for pancreatitis, 0.83 ± 0.09; and for fluid collections, 0.66 ± 0.09. There was a statistically significant difference (P < .05) between normal transplants and splenic vein thrombosis (P = .0003), rejection (P < .0001), and pancreatitis (P = .04). A significant difference was also seen between rejection and successful treatment thereof (P < .0001).

CONCLUSIONS

We developed a protocol that allowed us to successfully evaluate 96% of the pancreatic allografts studied. Furthermore, our data show that the RI can be used as a therapeutic guide. When the RI is less than 0.65, the risk of vascular abnormalities is very low; however, fluid collections may be present. When greater than 0.75, splenic vein thrombosis, pancreatitis, or rejection should be suspected. When greater than 0.9, rejection must be seriously considered.

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.

Preserved endocrine function in a pancreas transplant recipient with pancreatic panniculitis and antibody-mediated rejection

Pancreas transplantation is an effective treatment option for patients with complicated diabetes mellitus. Pancreas allograft recipients are followed with laboratory markers such as serum amylase, lipase and glucose levels. Hyperglycemia may indicate severe acute rejection and has recently been associated with antibody-mediated (humoral) rejection. In this report, we describe a unique case of a pancreas-after-kidney (PAK) transplant recipient with the rare presentation of pancreatic panniculitis, biopsy-proven severe acute cellular and antibody-mediated pancreas allograft rejection and surprisingly well-preserved endocrine function despite treatment with high dose steroids. We discuss the clinicopathologic features of antibody-mediated pancreas rejection, including the importance of correlating pancreas allograft biopsy, C4d staining and donor specific antibodies, to diagnose antibody-mediated rejection and initiate the correct treatment.

Imaging of pancreas transplantation and its complications

Pancreas transplantation is an effective treatment for type 1 diabetes mellitus and is being increasingly performed worldwide. Early recognition of graft-related complications is fundamental for graft survival; thus, radiologists must be aware of the transplantation technique, pancreas-graft imaging and postoperative complications. We present normal pancreas-graft imaging appearances and the imaging features of postoperative complications.

Pancreas transplant: recent advances and spectrum of features in pancreas allograft pathology

As result of improved surgical techniques and newer immunosuppressive regimens contributing significantly to better graft survival, exocrine pancreas transplantation remains the standard treatment of choice for patients with diabetes mellitus complicated by end-stage renal disease. Histologic assessment continues to play an important role in the diagnosis of graft complications after pancreas transplantation, especially for evaluating allograft rejection where histopathology is still considered the gold standard. This review elaborates on the current types of pancreas transplants and focuses on the patterns of allograft injury that are encountered in posttransplantation pancreas biopsies along with the pertinent differential diagnoses. In addition to optimal histologic assessment, as in any other organ transplant setting, clinical information including indication and duration of transplant as well as other serologic work-up must be taken into consideration during clinical decision making for optimal graft outcome.

Incidence of bleeding after 15,181 percutaneous biopsies and the role of aspirin

OBJECTIVE

The objective of our study was to report the incidence of bleeding after imaging-guided percutaneous core biopsy at a single center using a standardized technique.

MATERIALS AND METHODS

We performed a retrospective review of percutaneous core biopsies performed at our institution from January 2002 through February 2008. Data were collected at the time of biopsy, and clinical information was obtained 24 hours and 3 months after the biopsy. The specific information that was collected included the results of coagulation studies, aspirin use, the organ biopsied, the size of the biopsy needle, and the number of needle passes. Bleeding complications were defined using the Common Terminology Criteria for Adverse Events (CTCAE, version 3.0) established by the National Cancer Institute.

RESULTS

Among the 15,181 percutaneous core biopsies performed during the study period, 70 hemorrhages (0.5%) that were CTCAE grade 3 or greater were identified within 3 months of biopsy. The incidence of bleeding in patients taking aspirin within 10 days before biopsy was 0.6% (18/3,195), which was not statistically different compared with the incidence of bleeding in those not taking aspirin (52/11,986, 0.4%; p = 0.34). The incidence of bleeding after liver biopsy was 0.5%; kidney biopsy, 0.7%; lung biopsy, 0.2%; pancreas biopsy, 1.0%; and other biopsy, 0.2%. There were significant associations between major bleeding and serum platelet count and international normalized ratio (p < 0.001), although the association between major bleeding and the size of the biopsy needle was not significant (p = 0.97).

CONCLUSION

The overall incidence of major bleeding after imaging-guided percutaneous core needle biopsy is low. Recent aspirin therapy does not appear to significantly increase the risk of such bleeding complications.

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.

Ultra thin needle histology may have impact in diagnosing chronic pancreatitis

OBJECTIVE

Diagnosis of chronic pancreatitis is usually based on symptoms, ductal or parenchymal changes in imaging studies and function tests, but seldom on histology. Because the diagnosis of mild chronic pancreatitis is especially difficult, better tools to distinguish between chronic pancreatitis and normal pancreas are needed. Nowadays, cutting needles as thin as the widely used puncture needles are available. Using resected specimens, our aim was to evaluate whether these ultra-thin needles can take samples for histology that would allow verification of the diagnosis of chronic pancreatitis, with reference to a pancreatic wedge biopsy as the "gold standard".

MATERIAL AND METHODS

Fifty patients underwent pancreatic resection for various reasons. Two 20 G needle biopsies (outer diameter 0.8 mm, study biopsies) and a 5 x 5-mm wedge biopsy (reference biopsies) were taken from the same site of the specimen, avoiding possible neoplastic areas in the specimen. The samples were analyzed for the presence inflammation and fibrosis, both graded 0-3, as well as for any neoplastic changes without knowledge of the medical history, operative findings or final histology.

RESULTS

The reference biopsy showed normal tissue in 19 (38%) patients, chronic pancreatitis in 29 (58%) and only mild fibrosis (Grade 1) in 2 (4%) patients. In one patient the needle biopsy was insufficient for analysis. There was agreement between ultra-thin needle histology and the control specimen in 45/49 (92%) patients (correlation coefficient 0.9). Two biopsies of chronic pancreatitis and one mild fibrosis were misclassified as normal tissue, while one chronic pancreatitis biopsy was misclassified as an adenocarcinoma. The sensitivity of needle biopsy for chronic pancreatitis was 89%, specificity 100% and accuracy 94%.

CONCLUSIONS

Ultra-thin needle histology correlates well with the pancreatic wedge biopsy. Thus, these encouraging results warrant further clinical studies of different grades and types of chronic pancreatitis.

Pancreatic transplants: secretin-stimulated MR pancreatography

BACKGROUND

Our study was aimed to evaluate the functional status of pancreatic transplants using dynamic MR pancreatography after secretin stimulation.

METHODS

Thirteen asymptomatic patients previously submitted to isolated pancreas (n = 6) or combined kidney-pancreas (n = 7) transplantation, with enteric-portal pancreatic drainage, underwent MR examination at 1.5 T using a phased-array coil. After the acquisition of axial and coronal T1- and T2-weighted sequences, dynamic MR pancreatography was performed using a coronal breath-hold, thick-slab (40-60 mm), single-shot T2-weighted fast spin-echo sequence. After the intravenous administration of secretin (Secrelux, Sanochemia; 1 cU/kg body/weight), a single-slice image acquisition was repeated every 30 s up to 15 min. We estimated the calibre changes of the pancreatic ductal system and the filling of the donor's duodenum on the basis of pancreatic secretion after secretin stimulation, also evaluated by using a mean signal intensity/time histogram in a chosen region of interest including the transplanted pancreas and the connected small bowel.

RESULTS

All patients well tolerated the examination, and no side effects were reported after secretin administration. In 12/13 cases, a significant increase (more than 1 mm) in the diameter of the mean pancreatic duct was observed after secretin stimulation; in all patients, a noticeable filling of the duodenal graft was demonstrated during dynamic MR pancreatography on both qualitative and quantitative analyses.

CONCLUSIONS

Dynamic MR imaging after secretin administration allows non-invasive evaluation of exocrine function of the pancreatic transplants and could be used to differentiate patients with graft rejection from those with normal graft function.

The long-term management of pancreas transplantation

Diabetes mellitus (DM) is a major health problem worldwide, which affects 18.2 million individuals (6.3% of the population) in the United States. Currently, the prevalence of Type 1 DM in the United States is estimated to be 1,000,000 individuals, and 30,000 new cases are diagnosed each year. In addition to end-stage renal disease (ESRD), DM is associated with blindness, accelerated atherosclerosis, dyslipidemia, cardio- and cerebrovascular disease, amputation, poor quality of life, and overall lifespan reduction. It accounts for more than 160,000 deaths per year in the United States alone. In 2002, the annual national direct and indirect costs of Types 1 and 2 DM exceeded $130 billion, which included hospital and physician care, laboratory tests, pharmaceutical products, and patient workdays lost because of disability or premature death. Hyperglycemia alone or in concert with hypertension is the primary factor influencing the development of major diabetic complications. From 1990 to 2001, the number of existing ESRD cases to DM increased by more than 300%, while the rate per million populations increased from 167% to 491%. The number is expected to grow 10-fold by 2030 to 1.3 million accounting for 60% of ESRD population. To date, DM is the leading indication for transplantation and is the cause of ESRD in more than 40% of all transplant recipients each year.

Discontinuation of perioperative antiplatelet and anticoagulant therapy in stroke patients

Growing evidence suggests that perioperative withdrawal of ASA for secondary stroke prevention increases thromboembolic risk without the associated benefit of decreased bleeding complications. ASA maintenance is acceptable in many procedures, including invasive ones. Many procedures, in particular ophthalmologic, dermatologic, and dental surgeries, also are safe while continuing oral AC. Warfarin has been continued successfully even in some surgeries that have high bleeding risk. When the risk is too high, temporary bridging therapy with LWMH is safe in many populations. Although the exact thromboembolic risks associated with temporary cessation of AP and AC are unknown and likely low, morbidity and mortality associated with thromboembolism are high. Further studies investigating the risks and benefits of maintaining AP and AC during procedures, particularly invasive ones, are needed. Meanwhile, it is critical that physicians understand the risks and benefits of perioperative AP and AC and the variety of procedures in which these agents can be safely continued.

Complications of Abdominal and Pelvic Procedures: Computed Tomographic Diagnosis

The postprocedural period is a critical time in which serious complications can manifest. Localization of suspected complications following abdominal and pelvic procedures can be difficult on clinical evaluation alone. For example, abdominal pain after a colonoscopy may vary in etiology and can result from simple colonic spasm to colonic perforation, hemoperitoneum, or even splenic rupture. Vague abdominal pain following a renal biopsy may be due to minimal postprocedural bleeding into and around the kidney or may be due to potentially life-threatening hemorrhage. In such patients, computed tomography can play a crucial role in the rapid identification of complications as well guidance of subsequent patient management. The purpose of this article is to demonstrate the benefit of computed tomography-assisted diagnosis of complications associated with routine procedures performed on or throughout the abdomen and pelvis, including cardiac catheterization, colonoscopy, endoscopy, percutaneous biopsy, and interventional radiology procedures.

Low-dose aspirin for secondary cardiovascular prevention - cardiovascular risks after its perioperative withdrawal versus bleeding risks with its continuation - review and meta-analysis

OBJECTIVES

Low-dose aspirin given for secondary prevention of cardiovascular disease is frequently withdrawn prior to surgical or diagnostic procedures to reduce bleeding complications. This may expose patients to increased cardiovascular morbidity and mortality. Aim of the study was to review and quantify cardiovascular risks because of periprocedural aspirin withdrawal and bleeding risks with the continuation of aspirin.

METHODS

We screened MEDLINE (January 1970-October 2004) with additional manual cross-referencing for clinical studies, surveys on the opinions of doctors and guidelines.

RESULTS

Studies reporting the relative risk of acute cardiovascular events after aspirin withdrawal when compared with its continuation were not found. However, retrospective investigations revealed that aspirin withdrawal precedes up to 10.2% of acute cardiovascular syndromes. The time interval between discontinuation and acute cerebral events was 14.3 +/- 11.3 days, 8.5 +/- 3.6 days for acute coronary syndromes, and 25.8 +/- 18.1 days for acute peripheral arterial syndromes (P < 0.02 versus acute coronary syndromes). On aspirin-related bleeding risks, we obtained 41 (12 observational retrospective, 19 observational prospective, 10 randomized) studies, reporting on 49 590 patients (14 981 on aspirin). Baseline frequency of bleeding complications varied between 0 (skin lesion excision, cataract surgery) and 75% (transrectal prostate biopsy). Whilst aspirin increased the rate of bleeding complications by factor 1.5 (median, interquartile range: 1.0-2.5), it did not lead to a higher level of the severity of bleeding complications (exception: intracranial surgery, and possibly transurethral prostatectomy). Surveys amongst doctors on the management of this problem demonstrate wide variations. Available guidelines are scarce and in part contradictory.

CONCLUSIONS

Only if low-dose aspirin may cause bleeding risks with increased mortality or sequels comparable with the observed cardiovascular risks after aspirin withdrawal, it should be discontinued prior to an intended operation or procedure. Controlled clinical studies are urgently needed.

Interventional procedures in whole organ and islet cell pancreas transplantation

Pancreas organ transplantation has been a therapeutic option for the treatment of diabetes mellitus for over a decade. More recently, percutaneous injection of isolated pancreas islet cells via the portal vein has been developed as an exciting minimally invasive alternative procedure to whole organ transplantation, and one where the interventional radiologist may play a major role. This chapter reviews the role of image guided intervention in the whole organ pancreas transplant and describes the evolving technique of percutaneous islet cell transplantation.