Mf Hale

Capsule endoscopy:Current practice and future directions

Capsule endoscopy (CE) has transformed investigation of the small bowel providing a non-invasive, well tolerated means of accurately visualising the distal duodenum, jejunum and ileum. Since the introduction of small bowel CE thirteen years ago a high volume of literature on indications, diagnostic yields and safety profile has been presented. Inclusion in national and international guidelines has placed small bowel capsule endoscopy at the forefront of investigation into suspected diseases of the small bowel. Most commonly, small bowel CE is used in patients with suspected bleeding or to identify evidence of active Crohns disease (CD) (in patients with or without a prior history of CD). Typically, CE is undertaken after upper and lower gastrointestinal flexible endoscopy has failed to identify a diagnosis. Small bowel radiology or a patency capsule test should be considered prior to CE in those at high risk of strictures (such as patients known to have CD or presenting with obstructive symptoms) to reduce the risk of capsule retention. CE also has a role in patients with coeliac disease, suspected small bowel tumours and other small bowel disorders. Since the advent of small bowel CE, dedicated oesophageal and colon capsule endoscopes have expanded the fields of application to include the investigation of upper and lower gastrointestinal disorders. Oesophageal CE may be used to diagnose oesophagitis, Barretts oesophagus and varices but reliability in identifying gastroduodenal pathology is unknown and it does not have biopsy capability. Colon CE provides an alternative to conventional colonoscopy for symptomatic patients, while a possible role in colorectal cancer screening is a fascinating prospect. Current research is already addressing the possibility of controlling capsule movement and developing capsules which allow tissue sampling and the administration of therapy.

Capsule endoscopy as a panenteric diagnostic tool

Capsule endoscopy (CE), first described in 20001, may be one of the most important advances in gastrointestinal (GI) diagnostics since the introduction of endoscopy. A swallowed pill camera acquires images (subsequently converted to video format on a computer) as peristalsis propagates it through the GI tract. The first model, designed to examine the small bowel and overcome the technical difficulty of flexible enteroscopy, has been adopted widely by many Western gastroenterologists, and in some countries is seen as the first-choice modality for small-bowel imaging2. The wider application of this technology, however, and its role in disorders of interest to surgeons seem unappreciated. The commonest indication for small-bowel CE is GI bleeding (occult or overt), conventionally after nondiagnostic upper and lower GI endoscopic and radiological investigation3. CE identifies pathology in 46–60 per cent of these patients3, and is more sensitive than small-bowel barium contrast radiology, computed tomography (CT), magnetic resonance imaging (MRI), push enteroscopy and angiography4. Flat vascular lesions (angioectasias) and inflammatory disease are the commonest diagnoses, and may be apparent on direct mucosal visualization before becoming evident on radiological imaging. Thermal ablation of angioectasia or a need for biopsy requires flexible enteroscopy, which has therefore become the interventional counterpart of CE in much the same way that endoscopic retrograde cholangiopancreatography is now the therapeutic counterpart of magnetic resonance cholangiopancreatography. The double-balloon enteroscope5 has inflatable balloons both on the tip of the enteroscope and on a fine overtube that glides over the scope. Passage of the enteroscope (through oral or anal routes) deep into the small bowel is achieved by sequential inflation and deflation of balloons to provide anchorage while incrementally advancing the enteroscope tip. Examinations take up to an hour, and usually require more sedation than other modes of endoscopy or general anaesthesia. Small-bowel tumours are reported in up to 9.6 per cent of CE examinations performed to investigate obscure GI bleeding3. These include malignant or potentially malignant (GI stromal tumours, adenocarcinoma, carcinoid, lymphoma), benign (haemangioma, adenoma, lipoma) and metastatic (particularly from melanoma, lung, renal or breast primaries) lesions. CE is more accurate than small-bowel barium radiology at detecting small-bowel tumours, and can also detect smaller lesions than MRI4. CE is not without limitations in the small bowel. It can miss some lesions that are largely submucosal. If there is a high index of suspicion, crosssectional imaging such as contrastenhanced CT is recommended. The sensitivity of CE in identifying inflammation has also presented some challenges: suspected Crohn’s disease may be difficult to confirm histologically; the use of non-steroidal anti-inflammatory drugs (including low-dose aspirin) is widespread and these drugs cause erosions in up to two-thirds of patients. Minor mucosal breaks occur in 10–15 per cent of healthy volunteers6. The main risk of CE is capsule retention, occurring in 1 per cent of patients with suspected bleeding, but in as many as 5–13 per cent of those known to have Crohn’s disease4. Radiological investigation, particularly small-bowel MRI, is seen as the mainstay of investigation for those with established penetrating or stenosing disease as transmural involvement can be defined in crosssection, but CE may still be used to assess mucosal activity. To confirm functional patency of the GI tract, a dissolving patency capsule (the same size and shape as the capsule endoscope) containing a radiofrequency tag has been developed (Agile patency capsule; Given Imaging, Yoqneam, Israel). Absence of the radiofrequency signal 30 h postingestion predicts safe GI transit of the capsule endoscope4. Further advances led to oesophageal CE. PillCam ESO (Given Imaging) has cameras at both ends, acquiring simultaneous bidirectional images at a higher rate (14 versus 2 per second) than the small-bowel capsule, and has sensitivities of 80, 100 and 83 per cent in diagnosing reflux oesophagitis, Barrett’s oesophagus and varices respectively, compared with upper GI endoscopy4. Although better tolerated by patients than conventional endoscopy, uptake in clinical practice has been limited. The development of the doubleheaded capsule overcame one of the obstacles to the use of a colon capsule:

Magnetically steerable gastric capsule endoscopy is equivalent to flexible endoscopy in the detection of markers in an excised porcine stomach model: results of a randomized trial

BACKGROUND AND STUDY AIMS Capsule endoscopy is well tolerated but control of its movement is needed in order to visualize the whole gastric surface. Technological developments have produced an external magnet to allow manipulation of the capsule within the gastric cavity. The aim of this study was to compare magnetically steerable gastric capsule endoscopy (MSGCE) with flexible endoscopy for the detection of beads in a porcine stomach. MATERIALS AND METHODS Beads were sewn onto the mucosal surface of 12 ex vivo porcine stomachs. Each model was examined by flexible endoscopy and MSGCE by two blinded investigators. MSGCE was performed according to a protocol using positional changes and magnetic steering. Outcome measures were number and location of beads identified, and duration of procedure. RESULTS Flexible endoscopy identified 79 /90 beads (88 %), and MSGCE identified 80 /90 (89 %). The difference in sensitivities was 1.11 (95 % confidence interval 0.06 - 28.26). Thus, MSGCE was noninferior to flexible endoscopy. Mean examination times for flexible endoscopy and MSGCE were 3.34 minutes and 9.90 minutes, respectively. CONCLUSION MSGCE was equivalent to conventional flexible endoscopy in the detection of beads in a porcine stomach model.

Point-of-care testing for celiac disease has a low sensitivity in endoscopy

BACKGROUND Celiac disease (CD) is a common but underdiagnosed condition. A rapid point-of-care test (POCT) could reduce lead times and missed diagnoses. OBJECTIVE To assess the utility of an immunoglobulin (Ig) A tissue transglutaminase (TTG) antibody POCT in an endoscopic setting. DESIGN Prospective observational study. SETTING A single UK university hospital. PATIENTS Patients presenting with suspected CD, known CD, and routine endoscopy for upper GI symptoms. INTERVENTIONS All patients were tested with POCT, serum TTG, endomysial antibody (EMA), and upper GI endoscopy with duodenal biopsies at the same visit. MAIN OUTCOME MEASUREMENTS Comparison was made with histology in all cases, with villous atrophy regarded as diagnostic of CD. RESULTS A total of 576 patients (63.5% female, mean [± standard deviation] age 49.7 years [± 17.6 years]) were recruited. A total of 523 patients had no prior diagnosis of CD, and 53 patients had known CD coming for reassessment. A total of 117 patients were newly diagnosed with CD, and 82 were positively identified by the POCT. Sensitivity, specificity, positive predictive value, and negative predictive value were 70.1%, 96.6%, 85.4%, and 91.8%, respectively. In comparison, TTG and EMA both performed significantly better than the POCT. Sensitivity and specificity of TTG were 91.0% and 83.5%, respectively, and EMA were 83.8% and 97.5%, respectively. Of patients with known CD coming for reassessment, 26 had villous atrophy, and POCT results were positive in 16 (61.5%). There was poor agreement between POCT and standard serology. LIMITATIONS High pre-test probability of CD. CONCLUSION The performance of this POCT was disappointing compared with standard serology and cannot at present be recommended within the context of an endoscopy unit.

Does magnetically assisted capsule endoscopy improve small bowel capsule endoscopy completion rate? A randomised controlled trial.

Background and study aims: Delayed gastric emptying is a significant factor in incomplete small bowel capsule examinations. Gastric transit could be hastened by external magnetic control of the capsule. We studied the feasibility of this approach to improve capsule endoscopy completion rates. Patients and methods: Prospective, single-center, randomized controlled trial involving 122 patients attending for small bowel capsule endoscopy using MiroCam Navi. Patients were randomized to either the control group (mobilisation for 30 minutes after capsule ingestion, followed by intramuscular metoclopramide 10 mg if the capsule failed to enter the small bowel) or the intervention group (1000 mL of water prior to capsule ingestion, followed by positional change and magnetic steering). Outcome measures were capsule endoscopy completion rate, gastric clarity and distention, relationship of body habitus to capsule endoscopy completion rate (CECR), and patient comfort scores. Results: 122 patients were recruited (61 each to the control and intervention groups: mean age 49 years [range 21 – 85], 61 females). There was no significant difference in CECR between the two groups (P = 0.39). Time to first pyloric image was significantly shorter in the intervention group (P = 0.03) but there was no difference in gastric transit times (P = 0.12), suggesting that magnetic control hastens capsular transit to the gastric antrum but does not influence duodenal passage. Gastric clarity and distention were significantly better in the intervention group (P < 0.0001 and P < 0.0001 respectively). Conclusions: Magnetic steering of a small bowel capsule is unable to overcome pyloric contractions to enhance gastric emptying and improve capsule endoscope completion rate. Excellent mucosal visualisation within the gastric cavity suggests this technique could be harnessed for capsule examination of the stomach.

Current and future role of magnetically assisted gastric capsule endoscopy in the upper gastrointestinal tract

Capsule endoscopy first captivated the medical world when it provided a means to visualize the small bowel, which was previously out of endoscopic reach. In the subsequent decade and a half we continue to learn of the true potential that capsule endoscopy has to offer. Of particular current interest is whether capsule endoscopy has any reliable investigative role in the upper gastrointestinal tract. Much research has already been dedicated to enhancing the diagnostic and indeed therapeutic properties of capsule endoscopy. Specific modifications to tackle the challenges of the gut have already been described in the current literature. In the upper gastrointestinal tract, the capacious anatomy of the stomach represents one of many challenges that capsule endoscopy must overcome. One solution to improving diagnostic yield is to utilize external magnetic steering of a magnetically receptive capsule endoscope. Notionally this would provide a navigation system to direct the capsule to different areas of the stomach and allow complete gastric mucosal examination. To date, several studies have presented promising data to support the feasibility of this endeavour. However the jury is still out as to whether this system will surpass conventional gastroscopy, which remains the gold standard diagnostic tool in the foregut. Nevertheless, a minimally invasive and patient-friendly alternative to gastroscopy remains irresistibly appealing, warranting further studies to test the potential of magnetically assisted capsule endoscopy. In this article the authors would like to share the current state of magnetically assisted capsule endoscopy and anticipate what is yet to come.

The diagnostic accuracy of faecal calprotectin and small bowel capsule endoscopy and their correlation in suspected isolated small bowel Crohn's disease.

Introduction Faecal calprotectin (FC) is less accurate at identifying inflammation in the small bowel than in the colon. Small bowel capsule endoscopy (SBCE) is a useful tool to detect small bowel inflammation. We investigated the diagnostic accuracy of FC and SBCE and their correlation in patients with suspected isolated small bowel Crohn’s disease. Patients and methods This was performed as a prospective single centre study including patients attending for SBCE with suspected small bowel Crohn’s disease. Patient demographics, symptoms, medications and blood parameters were collected. Capsule endoscopy findings were analysed against calprotectin values, final diagnosis and blood parameters. Results A total of 146 patients were included (99 females and 47 males) with a mean age of 38±14 years. FC of more than 50 mg/kg was not significantly associated with clinically relevant capsule endoscopy findings (P=0.25), correlation coefficient was 0.11. Sensitivity, specificity, positive and negative predictive values for FC at a cut-off of more than 50 mg/kg were 88.9% [95% confidence interval (CI): 65.3–98.6], 25.0% (95% CI: 17.8–33.4), 14.3 (95% CI: 8.4–22.2) and 94.1% (95% CI: 80.3–99.3), respectively. A raised FC was not significantly associated with an elevated C-reactive protein or the presence of anaemia (P=0.19 and 0.10, respectively). Conclusion FC performs modestly as a screening test to exclude small bowel inflammation. However, we recommend interpretation within the overall clinical context to avoid overlooking the infrequent patient with small bowel inflammation and a negative FC.

Unrestricted faecal calprotectin testing performs poorly in the diagnosis of inflammatory bowel disease in patients in primary care

Background Faecal calprotectin (FC) measurement distinguishes patients with inflammatory bowel disease (IBD) from those with irritable bowel syndrome but evidence of its performance in primary care is limited. Aims To assess the yield of IBD from FC testing in primary care. Methods Retrospective review of hospital records to assess the outcome following FC testing in primary care. Investigations for all patients undergoing FC testing in a single laboratory for 6 months from 1 October 2013 to 28 February 2014 were reviewed. Results 410 patients (162 male; median age 42; range 16–91) were included. FC>50 µg/g was considered positive (FC+). 148/410 (36.1%; median age 44 (17–91)) were FC+ (median FC 116.5 µg/g (51–1770)). 122/148 FC-positive patients (82.4%) underwent further investigation. 97 (65.5%) underwent lower gastrointestinal endoscopy (LGIE), of which 7 (7.2%) had IBD. 49/262 (18.7%) FC-negative (FC−) patients (FC ≤50 µg/g) (median age 47 (19–76)) also underwent LGIE, of whom 3 (6.1%) had IBD. IBD was diagnosed in 11/410 (2.7%; 4 ulcerative colitis, 3 Crohn’s disease, 4 microscopic colitis). 8/11 were FC+ (range 67–1170) and 3 FC−. At a 50 µg/g threshold, sensitivity for detecting IBD was 72.7%, specificity 64.9%, positive predictive value (PPV) 5.41% and negative predictive value 98.9%. Increasing the threshold to 100 µg/g reduced the sensitivity of the test for detecting IBD to 54.6%. Conclusions FC testing in primary care has low sensitivity and specificity with poor PPV for diagnosing IBD. Its use needs to be directed to those with a higher pretest probability of disease. Local services and laboratories should advise general practitioners accordingly.

PWE-062 Gastroscopy without a Gastroscope! Feasibility In a Porcine Model Using a Magnetic Capsule

Introduction There is little evidence that gastroscopy affects patient outcomes1, but it is uncomfortable and incurs the risk of intubation and sedation. Capsule endoscopy is a non-invasive tool used primarily to image the small and large bowel. Although a large volume organ, examination of the stomach might be enabled by magnetic control allowing manoeuvrability and positional change. Methods A standard porcine stomach model, commonly used for endoscopy training purposes was used in a feasibility study of magnetically steerable capsule endoscopy. Different coloured/shaped beads were sewn into each major location of the stomach (cardia, fundus, greater and lesser curve, anterior and posterior wall, antrum and D1). The stomach was distended with 1000mls of water. Endoscopy was performed according to a set protocol using a handheld magnet, Mirocam Navi (Intromedic Ltd), positional changes (supine, 30° right lateral, head down, 30° left lateral) and a “real time” viewer. The order and time each tag was identified was recorded alongside the total procedure time. Results All stomach tags were identified in 87.2% (41/47) of examinations. Missed tags (marked in figure as red dots, representing an incomplete examination) included antrum (3/6), cardia (2/6) and posterior wall (1/6): none were missed in the latter 25 procedures. Mean examination times for the first 23, second 23 and all procedures were 10.28, 6.26 (p < 0.001) and 8.27 (3.25–16.32) minutes and all were completed by 4 mins after 39 procedures. The order in which tags were identified in the mid-body of the stomach (greater, anterior and posterior) was variable and interchangeable. If this area was considered as one site, the order of tag identification would be: cardia (1), fundus (2), mid body (3), lesser curve (4), antrum (5) and D1 (6) in 76.6% of examinations. No difficulties were observed with the current procedure protocol and therefore no modifications recommended. Conclusion Examination of the upper gastrointestinal tract is feasible using a magnet and positional change as demonstrated in this porcine model. A learning curve was evident and this model might be used for training in the future. Further investigation using porcine models and in humans is necessary to fully realise the scope of this exciting novel technology. Abstract PWE-062 Figure Disclosure of Interest None Declared. Reference Offman JJ, Rabeneck L The effectiveness of endoscopy in the management of dyspepsia: a qualitative systematic review. Am J Med. 1999 Mar; 106(3):335–46.

Reassessing the value of gastroscopy for the investigation of dyspepsia

Objective To evaluate the diagnostic yield of investigating dyspepsia with oesophagogastroduodenoscopy (OGD) with or without mucosal biopsy. Design Retrospective service evaluation study. Setting Two teaching hospitals: The Royal Hallamshire Hospital and Northern General Hospital, Sheffield Teaching Hospitals NHS Foundation Trust, UK. Patients 500 patients, 55 years of age and over, who underwent OGD to investigate dyspepsia were included. The study period included a 3-month window. All OGDs were performed on an outpatient basis. Interventions Data were extracted from electronic OGD records within the study period. Main outcome measures Diagnostic yield provided by endoscopic examination and histological assessment. Results 378 patients (75.6%) were reported to have some form of endoscopic abnormality, and 417 patients (83.4%) had biopsies taken. The most common findings at OGD were gastritis (47.2%) and oesophagitis (24.4%). Oesophagogastric malignancy was seen in 1%. Diagnoses made endoscopically or histologically that would not have been appropriately managed by empirical therapies were seen in 16.2%. Conclusion OGD in dyspepsia influences patient management in approximately one-sixth of cases. However, the majority of patients are sufficiently managed with Helicobacter pylori testing and eradication and/or a trial of proton pump inhibitor therapy. Further non-invasive approaches are needed to identify patients who need endoscopy for biopsy or therapy.