Endoscopic evaluation of small intestine transplant grafts. Transplantation. 2012;94:757-762. [PMID: 22955230 DOI: 10.1097/tp.0b013e31825f4410]

Endoscopic Surveillance of the Intestinal Allograft: Recommendations From the Intestinal Rehabilitation and Transplant Association Working Group

Intestinal transplant (ITx) rejection lacks a reliable noninvasive biomarker and rejection surveillance relies on serial endoscopies and mucosal biopsies followed by histologic assessment. Endoscopic biopsies are also essential for identifying other ITx-related complications such as infectious, allergic, and inflammatory graft enteritis as well as post-transplant lymphoproliferative disease or graft versus host disease. In spite of its central role in ITx, published guidelines on endoscopy and biopsy are lacking and significant variability between centers in terms of timing and technical performance exists. Therefore, an international expert group convened and discussed several aspects related to the surveillance endoscopy after ITx with the aim to summarize and standardize its practice. This article summarizes these considerations on endoscopic ITx monitoring and highlights practices of surveillance and for-cause endoscopy, biopsy techniques, pathologic evaluation, potential risks and complications, outsourcing, and less-invasive monitoring techniques.

Idiopathic Ileal Ulceration After Intestinal Transplantation

Background

Idiopathic ileal ulceration after intestinal transplantation (ITx) has been discussed infrequently and has an uncertain natural history and relation to graft rejection. Herein, we review our experience with this pathology.

Methods

We retrospectively reviewed 225 ITx in 217 patients with minimum 1 y graft survival. Routine graft endoscopy was conducted up to twice weekly within the first 90 d after ITx, gradually decreasing to once yearly. Risks for ulceration over time were evaluated using Cox regression.

Results

Of 93 (41%) patients with ulcers, 50 were found within 90 d after ITx mostly via ileoscopy; delayed healing after biopsy appeared causal in the majority. Of the remaining 43 patients with ulcers found >90 d after ITx, 36 were after ileostomy closure. Multivariable modeling demonstrated within 90-d ulcer associations with increasing patient age (hazard ratio [HR], 1.027; P < 0.001) and loop ileostomy (versus Santulli ileostomy; HR, 0.271; P < 0.001). For ulcers appearing after ileostomy closure, their sole association was with absence of graft colon (HR, 7.232; P < 0.001). For ulcers requiring extended anti-microbial and anti-inflammatory therapy, associations included de novo donor-specific antibodies (HR, 3.222; P < 0.007) and nucleotide oligomerization domain mutations (HR, 2.772; P < 0.016). Whole-cohort post-ITx ulceration was not associated with either graft rejection (P = 0.161) or graft failure (P = 0.410).

Conclusions

Idiopathic ulceration after ITx is relatively common but has little independent influence on outcome; risks include ileostomy construction, colon-free ITx, immunologic mutation, and donor sensitization.

Endoscopy in the Surgically Altered Bowel

Improved utilization of surgical interventions to improve patient outcomes has led to an increased need to endoscopically evaluate and treat the bowel after surgery. The best outcomes are attained when the endoscopist coordinates with the surgeon, and in some cases the pathologist or radiologist to plan the procedure. Understanding the anatomy and pathology anticipated can allow planning for sedation, bowel cleanse and equipment needed. Surgically altered anatomy can create challenges that with planning can be overcome. This article will review how to prepare and navigate several of the most commonly encountered surgical interventions.

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.

Evaluating the diagnostic value of zoom endoscopic surveillance compared to routine biopsy after intestinal transplantation

BACKGROUND

After intestinal transplantation, close allograft monitoring especially during the early postoperative period is crucial since the intestine is a highly immunogenic organ. Current protocols are based on endoscopic and histologic examination with the latter one being linked to the risk of bleeding and perforation.

AIMS

Evaluation of the diagnostic value of endoscopy utilizing magnification to predict acute cellular rejection compared to routine allograft biopsies.

METHODS

Fourteen patients underwent the protocol with longitudinal zoom endoscopic and histological graft monitoring during the first year after transplantation. The intestinal mucosa was analyzed during endoscopy utilizing the SASAKI score while a minimum of two biopsies were taken during each examination. A new graduation of severity for acute cellular rejection based on the findings of the SASAKI score is established.

RESULTS

Endoscopic findings of 385 examinations and more than 1000 intestinal allograft biopsies were analyzed. A total of 7 acute cellular rejection episodes in 6/14 patients occurred. Allograft endoscopy was able to diagnose ACR with a sensitivity of 76% and a specificity of 82%.

CONCLUSIONS

Our results will be critical for refining protocols for allograft monitoring after intestinal transplantation thus paving the way towards less invasive measures.

Optical coherence tomography of small intestine allograft biopsies using a handheld surgical probe

SIGNIFICANCE

The current gold standard for monitoring small intestinal transplant (IT) rejection is endoscopic visual assessment and biopsy of suspicious lesions; however, these lesions are only superficially visualized by endoscopy. Invasive biopsies provide a coarse sampling of tissue health without depicting the true presence and extent of any pathology. Optical coherence tomography (OCT) presents a potential alternative approach with significant advantages over traditional white-light endoscopy.

AIM

The aim of our investigation was to evaluate OCT performance in distinguishing clinically relevant morphological features associated with IT graft failure.

APPROACH

OCT was applied to evaluate the small bowel tissues of two rhesus macaques that had undergone IT of the ileum. The traditional assessment from routine histological observation was compared with OCT captured using a handheld surgical probe during the days post-transplant and subsequently was compared with histophaology.

RESULTS

The reported OCT system was capable of identifying major biological landmarks in healthy intestinal tissue. Following IT, one nonhuman primate (NHP) model suffered a severe graft ischemia, and the second NHP graft failed due to acute cellular rejection. OCT images show visual evidence of correspondence with histological signs of IT rejection.

CONCLUSIONS

Results suggest that OCT imaging has significant potential to reveal morphological changes associated with IT rejection and to improve patient outcomes overall.

The role of endoscopy in the small intestinal transplant recipient: A review

Intestinal transplantation (ITx) is the treatment of choice for patients with intestinal failure who have developed life-threatening complications related to long-term parenteral nutrition. Patients may also undergo ITx as part of a combined liver-intestine or multivisceral transplant for a variety of indications, most commonly intestinal failure-associated liver disease or porto-mesenteric thrombosis. Endoscopy plays a critical role in the posttransplant management of these patients, most commonly in the diagnosis and management of rejection, which occurs in up to 30-40% of patients within the first-year posttransplant. With a lack of noninvasive biomarkers to identify the presence of rejection, endoscopy and biopsy remain the gold standard for its diagnosis. Endoscopic evaluation of the graft is also important in the identification of other complications post-ITx, including posttransplant lymphoproliferative disorder, graft-versus-host disease, and enteric infections. Each patient's posttransplant anatomy may be slightly different, making endoscopy sometimes technically challenging and necessitating clear and frequent communication with the surgical team in order to help identify the highest yield approach. Herein, we review the most common pathologies found endoscopically in the post-ITx patient and describe some of the unique challenges the endoscopist faces when evaluating these complex patients.

Graft assessment for acute rejection after intestinal transplantation: current status and future perspective

Intestinal transplantation has since its inception evolved as a lifesaving treatment option for patients with irreversible intestinal failure who can no longer be sustained on parenteral nutrition. Improvement in short-term survival after transplantation has also justified the expansion of treatment indications. Unfortunately, success is somewhat limited by a plateau observed in long-term survival. The reason for this sub-optimal long-term result experienced in this cohort may in part be attributed to the intestinal graft with the lymphoid content it carries inflicting the host with multiple complications where acute cellular rejection is one of the most common causes for graft loss. Graft monitoring is for this reason of paramount importance and detection of rejection at an early stage essential to enable early instigation of treatment and successful reversal of the pathology. Due to the challenges in diagnosing acute rejection with a noninvasive marker we are still limited to a surveillance protocol using endoscopy and biopsies for the diagnosis of rejection. The purpose of our paper is to review the adequacy of different methods in monitoring the graft for acute rejection using biomarkers, endoscopy and imaging. In conclusion, the evidence base continues to support the use of histology for the diagnosis of acute rejection. The role of biomarkers are still debatable, although markers such as calprotectin might be beneficial in excluding an ongoing process.

Surveillance of Rejection After Intestinal Transplantation Using an Image Enhanced Endoscopy "VENCH" Scoring System

BACKGROUND

Graft rejection after intestinal transplantation remains challenging. We aimed to use endoscopy for rejection prediction.

MATERIALS AND METHODS

Patients ≥7 years old who underwent intestinal transplantation between November 2016 and September 2019 were prospectively enrolled. Magnifying endoscopy under narrow-band imaging was performed through ileostomy. Endoscopic findings were reported as five components (each graded from 0-2): "V" (villi appearance), "E" (erythema), "N" (capillary network), "C" (crypt widening), and "H" (heterogeneity). The correlation between histological severity and endoscopic score was analyzed.

RESULTS

Ninety-nine endoscopic biopsies from three female and one male patient were analyzed. The mean ± SD age was of 41.25±13.77 (range 29-58) years. Three short bowel syndrome patients after multiple intestinal resections and one with chronic intestinal pseudo-obstruction were indicated for intestinal transplantation. Sensitivity, specificity, and accuracy of V, E, N, C, and H scores for predicting rejection were 97.4%, 45.9%, 65.7%; 94.7%, 70.5%, 79.8%; 97.4%, 52.5%, 69.7%; 94.7%, 54.1%, 69.7%; and 97.4%, 62.3%, 75.8%, respectively. Pearson's correlation coefficients between total and individual V, E, N, C, H scores and histological rejection were 0.79, 0.64, 0.70, 0.71, 0.73, and 0.66, respectively (P < .001). To predict mild and moderate/severe rejection, total scores more than 4 and 6 had the sensitivity/specificity of 87.50%/57.38% and 96.67%/85.25%, respectively (area under the ROC 0.791 and 0.987).

CONCLUSION

Endoscopic VENCH scoring is promising for predicting rejection after IT. More studies are warranted to validate such results. (ClinicalTrials.gov number, NCT03616548.).

[Short bowel syndrome]

The paper gives information on the classification, pathogenesis, and clinical manifestations of short bowel syndrome following after intestinal resection. It discusses the treatment and rehabilitation of patients with this condition.

Intestinal transplants: review of normal imaging appearance and complications

Intestinal transplant (IT) is one of the least common forms of organ transplant but is increasing both in volume of cases and number of centers performing intestinal transplants, with the busiest centers in North America and Europe. IT can be performed in isolation or as part of a multivisceral transplant (MVT). Intestinal failure either in the form of short gut syndrome or functional bowel problems is the primary indication for IT. The normal post-surgical anatomy can be variable due to both recipient anatomy in regard to amount of residual bowel and status of native vasculature as well as whether the transplant is isolated or part of a multivisceral transplant. Complications of isolated IT and IT as part of an MVT include complications shared with other types of organ transplants such as infection, rejection, post-transplant lymphoproliferative disorder and graft versus host disease. Mechanical bowel complications of the graft include bowel obstruction, stricture, leak, perforation and enterocutaneous fistula. Lastly, vascular complications of both the venous and arterial anastomoses including stricture and pseudoaneurysm occur.

The endoscopic surveillance of the transplanted small intestine: a single center experience and a proposal for a grading score

OBJECTIVE

Microscopic examination of endoscopic biopsies forms the basis of acute cellular rejection (ACR) monitoring after intestinal transplantation (ITx). The endoscopy findings during acute rejection (AR) are known but a grading system for its severity is lacking. We designed and implemented a five-stage grading score based on acknowledged endoscopic features of AR, to allow a faster preliminary diagnosis of AR and intra- and interpatient comparisons.

METHODS

Two investigators reviewed and graded the endoscopy reports after 28 ITx using a novel score and correlated the results with pathology findings.

RESULTS

We reviewed 512 ileoscopies: 370 examinations (74%) were normal (G0), 59 had mild alterations (erythema, edematous villi-G1) and 36 showed moderate changes (erosions, blunted villi-G2); 17 ileoscopies revealed advanced changes (ulcerations, villus loss-G3). In 18 endoscopies the changes were severe (mucosal loss-G4). Inter-reviewer agreement was very good (kappa = 0.81). Biopsies from 86 endoscopy sessions (17%) indicated ACR with 63 cases having moderate or severe ACR. For mild ACR the sensitivity of the score was 29% and the specificity was 86% whereas the positive (PPV) and negative predictive values (NPVs) were 14% and 93% respectively. During advanced ACR the sensitivity and specificity were 92% and 86%, respectively whereas the PPV and NPV were 49% and 98% respectively.

CONCLUSIONS

Endoscopy alone has a limited ability to reliably diagnose intestinal ACR. We suggest a novel grading score summarizing ACR findings and allowing comparisons between intestinal graft endoscopies.

Mycophenolate mofetil toxicity mimicking acute cellular rejection in a small intestinal transplant

Mycophenolate mofetil (MMF) is an important medication used for maintenance immunosuppression in solid organ transplants. A common gastrointestinal (GI) side effect of MMF is enterocolitis, which has been associated with multiple histological features. There is little data in the literature describing the histological effects of MMF in small intestinal transplant (SIT) recipients. We present a case of MMF toxicity in a SIT recipient, with histological changes in the donor ileum mimicking persistent acute cellular rejection (ACR). Concurrent biopsies of the patient’s native colon showed similar changes to those from the donor small bowel, suggesting a non-graft specific process, raising suspicion for MMF toxicity. The MMF was discontinued and complete resolution of these changes occurred over three weeks. MMF toxicity should therefore be considered as a differential diagnosis for ACR and graft-versus-host disease in SITs.

Current status of intestinal and multivisceral transplantation

Clinical-nutritional autonomy is the ultimate goal of patients with intestinal failure (IF). Traditionally, patients with IF have been relegated to lifelong parenteral nutrition (PN) once surgical and medical rehabilitation attempts at intestinal adaptation have failed. Over the past two decades, however, outcome improvements in intestinal transplantation have added another dimension to the therapeutic armamentarium in the field of gut rehabilitation. This has become possible through relentless efforts in the standardization of surgical techniques, advancements in immunosuppressive therapies and induction protocols and improvement in postoperative patient care. Four types of intestinal transplants include isolated small bowel transplant, liver-small bowel transplant, multivisceral transplant and modified multivisceral transplant. Current guidelines restrict intestinal transplantation to patients who have had significant complications from PN including liver failure and repeated infections. From an experimental stage to the currently established therapeutic modality for patients with advanced IF, outcome improvements have also been possible due to the introduction of tacrolimus in the early 1990s. Studies have shown that intestinal transplant is cost-effective within 1-3 years of graft survival compared with PN. Improved survival and quality of life as well as resumption of an oral diet should enable intestinal transplantation to be an important option for patients with IF in addition to continued rehabilitation. Future research should focus on detecting biomarkers of early rejection, enhanced immunosuppression protocols, improved postoperative care and early referral to transplant centers.

Initial Experience of Video Capsule Endoscopy After Intestinal Transplantation

BACKGROUND

Intestinal transplantation is a procedure which inflicts immunological and infectious complications that affect the transplanted graft, posing both diagnostic and therapeutic challenges. Video capsule endoscopy (VCE) offers easy access to the entire small intestine and presents itself as an interesting option. However, at present, no studies evaluating the usefulness of video capsule endoscopies in this setting have been published. Our aim was to evaluate the usefulness of VCE in detecting complications that arise after intestinal transplantation.

METHODS

We included 7 adult patients with either isolated intestine (n = 1) or multivisceral grafts (n = 6). These patients underwent 12 VCE between 2004 and 2015 at the Sahlgrenska University Hospital. The median age was 42 (21-67) years (4 women/3 men). VCE was used in clinical situations where the conventional diagnostic methods failed to provide answers to the clinical question.

RESULTS

Indications for the procedure were: suspicion of rejection (n = 4 examinations), gastrointestinal dysmotility (n = 4 examinations), high stomal output (n = 2 examinations), suspicion of lymphoproliferative disease in the transplanted graft (n = 1 examination), and clinical surveillance (n = 1 examination). The median time after transplantation for performing an examination was 740 (26-3059) days. VCE was useful in 83% of the examinations and the results influenced the planned management. The overall agreement between VCE findings and biopsies was moderate (κ = 0.54, P = 0.05) but increased when comparing the presence of inflammation/rejection (κ = 0.79, P < 0.001).

CONCLUSIONS

VCE is a promising diagnostic method after intestinal transplantation. However, larger studies are needed to evaluate its potential risks and gains.

Endoscopy Following Pediatric Intestinal Transplant

OBJECTIVES

Biopsies remain the criterion standard in the diagnosis of intestinal transplant (ITx) rejection, and gastrointestinal endoscopy plays a pivotal role in patient management. Herein, we describe a single-center 23-year endoscopic experience in pediatric ITx recipients.

METHODS

A retrospective review of endoscopy and pathology reports of all ITx recipients <18 years old transplanted between 1991 and 2013 was performed with the aim of describing the procedural indications, findings, and complications.

RESULTS

A total of 1770 endoscopic procedures within 1014 sessions were performed. A combination of esophagogastroduodenoscopy and ileoscopy was the most common procedure (36%). Increased stool output (35%) and surveillance endoscopy (32%) were the most common indications. A total of 162 episodes of biopsy-proven rejection were diagnosed. The first episode of rejection occurred at a median of 1 month after ITx. Of histology-proven rejections, 45% had normal-appearing endoscopies. The rate of procedural complications, including but not limited to bleeding and perforation, was 1.8%.

CONCLUSIONS

Endoscopy with biopsy plays a significant role in the care of ITx recipients. Multiple procedures are required for graft surveillance, diagnosis of rejection, subsequent treatment, and follow-up of therapy. The gross endoscopic appearance, particularly in mild to moderate acute cellular rejection, does not correlate well with histology. Complex anatomy, complication rates that are higher than patients with non-ITx pediatric endoscopy, and timely histologic interpretation by experienced pathologists are reasons that these procedures should be performed at centers accustomed to caring for ITx recipients. The field would benefit from the development of a noninvasive biomarker to reliably and efficiently detect rejection.

Isolated small bowel transplantation outcomes and the impact of immunosuppressants: Experience of a single transplant center

AIM: To investigate patient and graft outcomes in isolated small bowel transplant (SBTx) recipients and immunosuppressant induction agent impact on outcomes.

METHODS: A retrospective review of the perioperative data of patients who underwent SBTx transplant during an 8-year period was conducted. The intraoperative data were: patient demographics, etiology of short gut syndrome, hemodynamic parameters, coagulation profiles, intraoperative fluid and blood products transfused, and development of post-reperfusion. The postoperative data were: hospital/intensive care unit stays, duration of mechanical ventilation, postoperative incidence of acute kidney injury, and 1-year patient and graft outcomes. The effects of the three immunosuppressant induction agents (Zenapax, Thymoglobulin, Campath) on patient and graft outcomes were reviewed.

RESULTS: During the 8-year period there were 77 patients; 1-year patient and graft survival were 95% and 86% respectively. Sixteen patients received Zenapax, 22 received Thymoglobulin, and 39 received Campath without effects on patient or graft survival (P = 0.90, P =

0.14, respectively). The use of different immune induction agents did not affect the incidence of rejection and infection during the first 90 postoperative days (P = 0.072, P = 0.29, respectively). The Zenapax group received more intraoperative fluid and blood products and were coagulopathic at the end of surgery. Zenapax and Thymoglobulin significantly increased serum creatinine at 48 h (P = 0.023) and 1 wk (P = 0.001) post-transplant, but none developed renal failure or required dialysis at the end of the first year.

CONCLUSION: One-year patient and graft survival were 95% and 86%, respectively. The use of different immunosuppressant induction agents may affect the intraoperative course and short-term postoperative morbidities, but not 1-year patient and graft outcomes.