Phil Tozer

A diagnostic accuracy meta-analysis of endoanal ultrasound and MRI for perianal fistula assessment.

BACKGROUND: Imaging modalities such as endoanal ultrasound or MRI can be useful preoperative adjuncts before the appropriate surgical intervention for perianal fistulas. OBJECTIVES: We present a systematic review of published literature comparing endoanal ultrasound with MRI for the assessment of idiopathic and Crohn’s perianal fistulas. DESIGN: A meta-analysis was performed to obtain pooled values for specificity and sensitivity. SETTINGS: Electronic databases were searched from January 1970 to October 2010 for published studies. PATIENTS AND INTERVENTIONS: Four studies were used in our analysis. There were 241 fistulas in the ultrasound group and 240 in the magnetic resonance group. RESULTS: The combined sensitivity and specificity of magnetic resonance for fistula detection were 0.87 (95% CI: 0.63-0.96) and 0.69 (95% CI: 0.51-0.82). There was a high degree of heterogeneity between studies reporting on MRI sensitivity (df = 3, I2 = 93%). This compares to a sensitivity and specificity for endoanal ultrasound of 0.87 (95% CI: 0.70-0.95) and 0.43 (95% CI: 0.21-0.69). There was a high degree of heterogeneity between studies reporting on endoanal ultrasound sensitivity (df = 3, I2 = 92%). CONCLUSIONS: From the available literature, the summarized performance characteristics for MRI and endoanal ultrasound demonstrate comparable sensitivities at detecting perianal fistulas, although the specificity for MRI was higher than that for endoanal ultrasound. Both specificity values are considered to be diagnostically poor, however. The high degree of data heterogeneity and the shortage of applicable studies precludes any firm conclusions being made for clinical practice. Future trials with improved study design (including prospective data collection and consideration of verification bias) may help to further clarify the role of MRI in the assessment and treatment response monitoring of perianal fistulas (particularly in patients with Crohn’s disease).

Long-term MRI-guided combined anti-TNF-α and thiopurine therapy for crohn's perianal fistulas†‡

Background: Anti‐tumor necrosis factor (TNF) therapy heals many Crohns disease (CD) anal fistulas clinically but the rate, extent, and durability of deep tissue healing and factors influencing long‐term outcome are unknown. Methods: Consecutive patients with CD‐related perianal (anal, rectovaginal, anolabial) fistulas treated with infliximab or adalimumab were monitored prospectively both clinically and radiologically using magnetic resonance imaging (MRI). Results: Forty‐one consecutive patients with CD‐related perianal fistulas were treated with infliximab (n = 32) or adalimumab (n = 9; following infliximab failure) in combination with a thiopurine (unless intolerant). Fifty‐eight percent of all patients, comprising 66% and 43% of infliximab and adalimumab‐treated patients, respectively, demonstrated remission or response at 3 years. Thirty‐three percent of infliximab treated patients maintained clinical remission at 3 years. Radiological healing lagged behind clinical remission by a median of 12 months. The likelihood of clinical remission at any time was five times greater in patients who had early clinical response within 6 weeks than those without. A higher number of fistula tracts was associated with reduced clinical remission. All patients who achieved radiological healing maintained healing on infliximab treatment, while only 43% maintained healing after cessation of anti‐TNF therapy. Conclusions: Combination anti‐TNF and thiopurine therapy provides sustained benefit in patients with perianal CD fistula. Early clinical response is associated with subsequent clinical remission. Radiological healing is slower than clinical healing. Radiologically healed fistula tracts maintain healing on infliximab but can recur after cessation of therapy. (Inflamm Bowel Dis 2012)

Developing a core outcome set for fistulising perianal Crohn’s disease

Objective Lack of standardised outcomes hampers effective analysis and comparison of data when comparing treatments in fistulising perianal Crohn’s disease (pCD). Development of a standardised set of outcomes would resolve these issues. This study provides the definitive core outcome set (COS) for fistulising pCD. Design Candidate outcomes were generated through a systematic review and patient interviews. Consensus was established via a three-round Delphi process using a 9-point Likert scale based on how important they felt it was in determining treatment success culminating in a final consensus meeting. Stakeholders were recruited nationally and grouped into three panels (surgeons and radiologists, gastroenterologists and IBD specialist nurses, and patients). Participants received feedback from their panel (in the second round) and all participants (in the third round) to allow refinement of their scores. Results A total of 295 outcomes were identified from systematic reviews and interviews that were categorised into 92 domains. 187 stakeholders (response rate 78.5%) prioritised 49 outcomes through a three-round Delphi study. The final consensus meeting of 41 experts and patients generated agreement on an eight domain COS. The COS comprised three patient-reported outcome domains (quality of life, incontinence and a combined score of patient priorities) and five clinician-reported outcome domains (perianal disease activity, development of new perianal abscess/sepsis, new/recurrent fistula, unplanned surgery and faecal diversion). Conclusion A fistulising pCD COS has been produced by all key stakeholders. Application of the COS will reduce heterogeneity in outcome reporting, thereby facilitating more meaningful comparisons between treatments, data synthesis and ultimately benefit patient care.

Is FiLaC the answer for more complex perianal fistula

The ancient Greeks are often credited as the first to acknowledge the challenges of perianal sepsis and associated fistulae [1]. Indeed, 2500 years of enquiry have seen numerous procedures offered to patients; many burdened by their own inherent problems and none widely considered to represent optimal treatment. Modern-day anal fistula management can be complex and require a multidisciplinary input in Crohn’s disease. The addition of radiological assessment to thorough clinical examination facilitates anatomical delineation, usually using Parks’ classification. The most difficult fistulae are often those too high to be amenable to laying open, which has the best chance of healing. Whilst rarely a life-threatening condition, the disappointment of recurrent failure is difficult for patients, who may have to consider treatments which can impair sphincter function. One problem is the contentious issue of defining treatment success and/or fistula healing which are often synonymous. The Societa Italiana di Chirurgia ColoRettale (SICCR) recently published a position statement on perianal fistulae [2]. Amongst a variety of issues, they specifically addressed the use of Fistula Laser Closing (FiLaC) to ablate the fistulous tract, with or without internal opening closure, in ‘complex fistulae’. The 2C recommendation was based on the literature prior to the recently published study by Wilhelm and colleagues in this journal [3], but they nevertheless highlighted the low morbidity and potential of this procedure and that it warranted further investigation. A separate expert group from the UK looked specifically at perianal fistulae in Crohn’s disease [4]. They sought to address a number of areas in perianal Crohn’s disease and included details of surgical care in their questionnaire. Unfortunately, only 0.6% of surgeons across 32 centres cited experience of FiLaC reflecting limited uptake at present. In this journal, Wilhelm and colleagues have reported on their long-term follow-up data using FiLAC in patients with diagnosed high fistulae [3]. FiLaC uses a radial emitting diode laser to obliterate the fistula with or without closing the internal opening. This study, currently the largest series, included 117 patients over a period of just under 5 years who had undergone clinical and radiological examination with endoanal ultrasound (EAUS). Both surgery and EAUS were performed by a single surgeon. The primary outcome measure was fistula healing, the definition of which has often proved to be a contentious issue in fistula-in-ano, many authors using follow-up which is too short or failing to use imaging to prove the absence of persistent occult tracts. By contrast, Wilhelm used a combined clinical and radiological endpoint with a strict definition. A fistula was considered to have permanently healed if at 1 year all symptoms had completely disappeared, there was no evidence of recurrence (or persistence) on clinical, proctoscopic and endosonographic examination, and there were no additional interventions required. A similar combined (but less stringent) clinical and radiological endpoint was recently used by Panes et al. in their study on stem cells in Crohn’s anal fistula [5]. The use of combined endpoints and longer follow-up is a welcome development in fistula surgery research. Interestingly, the authors used a further definition of success: primary success if the fistula fulfilled the healing & Manish Chand m.chand@ucl.ac.uk

Mo1763 Clinical Risk Factors for Crohn's Disease Postoperative Recurrence are Reflected in Alterations in Mucosally Adherent Microbiota at Surgical Resection

Introduction Clinical risk factors for Crohn9s disease (CD) recurrence after ileo-caecal resection (ICR) include smoking status, perforating disease and >1 surgical resection. The underlying mechanisms contributing to clinical risk are unknown. We aimed to study the relationship between risk factors and gut microbiota. Methods Samples of macroscopically inflamed and non-inflamed small bowel from patients undergoing surgical resection for CD were analysed. Samples were snap frozen in liquid nitrogen. Cryosections were cut and the frozen sections were hybridised with oligonucleotide probes targeting the microbial 16S rRNA of total bacteria, Escherichia coli , Bacteroides-Prevotella, Faecalibacterium prausnitzii , Clostrium coccoides - Eubacterium rectale and bifidobacteria. The hybridised mucosa associated microbiota (MAM) were identified and quantified. Patients with ≥1 risk factor were classified as high risk for disease recurrence. Results Fifteen patients underwent ICR (10 female); 9 were high risk (6 smokers, 4 fistulating disease and 2 recurrent resection- 3 patients had multiple risk factors). Faecalibacterium prausnitzii numbers in inflamed operative samples were lower in smokers compared with non-smokers (p=0.036). High-risk patients had lower numbers of bifidobacteria in both inflamed (p=0.006) and non-inflamed (p=0.01) operative samples compared with low risk patients. Conclusion The risk of post-operative CD recurrence may be predetermined at a pre-operative stage due to dysbiosis. The role of MAM as a tool to stratify risk requires further study. Drugs that modulate MAM may, in future, play a role in reducing post-operative recurrence. Competing interests None declared.

Dendritic cell homing and immune cell function in crohn's anal fistulae

Introduction The aetiology of perianal fistulating Crohns disease remains obscure but genetic, microbiological and immunological factors play a role. Dendritic cells (DC) are antigen presenting cells which sample mucosal-associated bacteria and migrate to lymph nodes to stimulate immune response via T cells. DC express homing markers to imprint on T cells and direct them to organs, for example, skin (cutaneous lymphocyte-associated antigen, CLA) and gut (α4β7 integrin). In IBD DC express more Toll-like receptors which recognise microbes and increase inflammatory cytokine levels. Aim to characterise immune cell composition and cytokine milieu of Crohns and idiopathic fistulae including DC phenotype and homing. Methods Biopsy samples were taken from Crohns and idiopathic anal fistulae. After overnight incubation (medium, 37°C, 5% CO2), ‘walk out’ cells isolated from the supernatant were analysed by flow cytometer. DC were identified and assessed for phenotype (myeloid or plasmacytoid) and homing molecules (CLA and α4β7). TH1/2 and 17 cytokine profile was determined using Multiplex analysis. Results Tract samples from 15 Crohns (CPD) and 12 idiopathic (IPD) anal fistula patients and rectal samples from 10 normal control patients were taken for immunological analysis. DC in CPD had significantly reduced levels of α4β7 and CLA compared with IPD. There was no significant difference in proportions of either myeloid or plasmacytoid DC, or of CD14, CD16, CD19 or CD3 cells. Crohns fistula tracts showed lower levels of CD65 than idiopathic fistula tracts (p=0.04). Levels of IL-2, IL-4, IL-6, IL-10, TNF and IFNγ were similar in Crohns and idiopathic fistulae and rectum of controls. IL-17a levels were higher in CPD than normal rectum and IPD (p=0.04). Table 1 PTH-064 Idiopathic anal fistula (IPD) (n=12) Crohns anal fistula (CPD) (n=15) Controls (n=10) Age 46.5 32 56.5 Gender (M:F) 9:3 8:7 5:5 Duration of perianal disease (years) 3.5 5.5 – Duration of luminal CD (years) – 12 – Location of luminal CD – 5×L2p – 4×L3p 2×p Stoma 0 3 0 Drugs – 2× oral steroids – 5× thiopurines Smoker 3 5 2 Conclusion Similarities between Crohns and idiopathic anal fistula immune cells and cytokines may suggest that in a formed tract, the immunological processes in both are similar. However, higher IL-17 levels may indicate strategies for diagnosis and treatment of Crohns anal fistulae. Aberrant expression of homing molecules on DC in Crohns perianal fistulae suggests a ‘non-directed’ immune response which may contribute to the pathophysiology.

TH1/TH17 profiles in crohn's disease: a cross sectional single centre study in postoperative crohn's disease

Introduction Th1 and Th17 pathways are implicated in Crohn9s disease (CD). In operative resection samples healthy ileum shows high TGFβ levels in patients who develop recurrence, with TGFβ being a known activator of the Th17 response. Other studies in CD show a dominant Th1 cytokine profile, with high levels of IFNγ, which reduce Th17 response and augment Th1 response. The relationship of Th1/Th17 cytokine profiles in postoperative CD has not been examined. The authors aimed to study tissue Th1/Th17 cytokine secretion after in vitro biopsy culture in postoperative CD. Methods Colonoscopy was undertaken in postoperative CD patients. Recurrence graded as no/minimal inflammation (Rutgeert Score (RS) ≥1) or progressive inflammation (RS≥2). Ileal biopsies were cultured overnight and cell free supernatants obtained. Supernatant cytokines (IL-2, IL-4, IL-10, IL-17 TNFα, INFg and IL-6) were assessed by flow cytometry using cytometric bead array (Becton Dickinson). Statistical analysis was via unpaired t tests. Results Consecutive patients attending endoscopy (n=24, 9M/15F) were identified. Mean age 45.0 years and time from I to C resection was 5.8 years; 5 patients were smokers. Drugs were thiopurines 13, Infliximab 1 and nil 10. Endoscopic severity was i0 n=5, i1 n=6, i2 n=5, i3 n=3, i4 n=5. Mean cytokine concentrations from supernatants are shown in the table 1. Comparison between RS≥1 and ≥2 showed that pro-inflammatory cytokines IL-17a (p Conclusion Cytokine profiles in those with RS≥2, show higher levels of IL-17a and IFNγ and reduced IL-10 compared to RS≥1. This profile supports a Th17 and Th1 mediated response as one of the early instigators of endoscopic progression in postoperative CD. The authors9 observation is consistent with recent findings of a T cell subset able to produce cytokines involved in both Th1 and Th17 responses. Previous therapies directed at Th1 pathway, for example, anti-IL-12p40 antibody ustekinumab and anti-IFNγ Fontolizumab failed to show significant clinical benefit in CD. Given our findings targeting the Th17 response, for example, with anti-IL-23 antibodies and anti-IL-17 may deliver improved therapeutic outcome.

Increase in Dendritic Cell Migration Markers CCR7 and CCR9 in the Neo-Terminal Ileum of Postoperative Crohn's Disease: An Adaptive Response to Bacterial Exposure?

Introduction Gut dendritic cells (DCs) are crucial in bacterial recognition, T cell signalling and inflammatory regulation. DC TLR expression is altered in CD: increased on myeloid DC (MDC) in colonic CD and reduced on plasmacytoid DCs (PDC) in postoperative CD (POCD) ileum. In active CD, peripheral CD4 and CD8 T cells showed increased intestinal homing with high CCR9 levels. In Crohn9s colonic tissues, CCR7, a homing marker crucial for DC trafficking to mesenteric lymph nodes, was elevated compared with controls. Additionally CCR7 expression on MDC is higher in ileal compared with colonic tissue in CD. CCR7 and CCR9 expression on DC in POCD is unknown. After ileo-caecal resection the neo-terminal ileum is exposed to the bacteria rich contents of the colon. The authors hypothesise that alteration in gut microflora after surgery may modulate expression of homing markers on DC from POCD patients. The authors aimed to examine homing marker expression on MDC and PDC from the ileum and the colon in healthy controls (HC) and POCD patients. Methods HC and POCD patients were identified at colonoscopy. Intestinal lamina propria mononuclear cells were collected using collagenase digestion and labelled with directly conjugated monoclonal antibodies to CCR7 and 9. PDC and MDC were characterised as CD11c+ve and –ve respectively and expression of CCR7 and 9 by multicolour flow cytometry measured. Statistical analysis was via unpaired t tests. In experiments with paired colonic and ileal samples paired t tests were performed. Results In paired samples, HC ileal CCR9+ve PDC concentrations were lower than colonic PDC (26.46±10.43/ml SEM vs 53.76±20.16/ml SEM, p There were significantly higher concentrations of CCR9+ve and CCR7+ve PDCs within ileal POCD compared with ileum normal controls (103.8±22.64/ml vs 37.68±7.434/ml, p=0.039 and 117.4±26.97/ml SEM vs 40.47±3.97/ml SEM, p=0.03). No differences in MDC concentrations of both homing markers in all types of tissue existed. Conclusion POCD neo-terminal ileum showed higher CCR7+ve and CCR9+ve PDC than normal ileum. This novel finding indicates a potential role for PDC in CD pathogenesis. The loss of the ileocaecal valve in POCD may alter microbiota flora exposure in the ileum with an adaptive response of CCR9+ve DC to a level seen in normal colonic tissue. Additionally, this may induce migration of PDC by upregulation of CCR7 expression. Further studies to examine the changes with disease progression may unravel the function of PDC in ileal POCD tissues.

MRI Guided Biologic Therapy for Crohn's Perianal Fistulae: 3 Year Follow up Data

Background: Thiopurine methyltransferase (TPMT) is a cytosolic enzyme involved in the metabolism of azathioprine and 6-mercaptopurine. Higher TPMT activity is associated with lower levels of the therapeutic metabolite 6-thioguanine (6-TG). Some therapeutic studies in patients with inflammatory bowel disease have excluded those with intermediate TPMT activity. A small difference in TPMT enzyme activity has been reported between AfricanAmericans and Caucasians. Our own preliminary data suggested that this difference may be more pronounced. We sought to further assess racial differences in TPMT activity to help determine optimal treatment strategies for patients with inflammatory bowel disease. Methods: A retrospective chart review from the electronic medical records of Henry Ford Health System was conducted for patients who had undergone testing for TPMT enzyme activity from June 2004 through September 2010. Testing was performed at Prometheus Laboratories (San Diego, CA). TPMT activity was categorized into low ( 21 EU). Results: 394 patients underwent TPMT testing during the study period. Race was available for 388 patients (246 women and 142 men). The population was composed of 223 Caucasians, 134 African-Americans, and 31 patients of other race. Mean TPMT level was 28.3 EU (SD 9.6) for Caucasians, 23.3 EU(SD 8.2) for African-Americans, and 27.5 EU (SD 9.0) for others (p <0.001). Mean TPMT activity for the 13 Middle Eastern patients in the population was 22.1 (SD 7.8) which was significantly lower than that of Caucasians (p = 0.024). Analysis by TPMT activity category showed that low activity was seen in only 2 patients, and both were Caucasians. Intermediate activity was seen in 37 of the 223 Caucasians (16.6%), 52 of 134 African-Americans (38.8%), and 7 of 31 other race patients (22.6%). Normal TPMT activity was seen for 184 of the 223 Caucasians (82.5%), 82 of the 134 African-Americans (61.2%), and 24 of the 31 patients of other race (77.4%). This distribution was statistically significant (p <0.001). Conclusions: Mean TPMT activity is lower in African-American and Middle Eastern patients compared to Caucasians. African-Americans are more likely to have intermediate TPMT activity compared to Caucasians. Therapeutic studies using 6-mercaptopurine and azathioprine that exclude patients with intermediate TPMT activity may exclude a high proportion of AfricanAmerican patients.