The National Institute for Clinical Excellence is examining wireless capsule endoscopy and will publish guidance on its safety and efficacy to the NHS in England, Wales and Scotland. The Institute's Interventional Procedures Advisory Committee has considered the available evidence and the views of Specialist Advisors, who are consultants with knowledge of the procedure. The Advisory Committee has made provisional recommendations about wireless capsule endoscopy.

This document summarises the procedure and sets out the provisional recommendations made by the Advisory Committee. It has been prepared for public consultation. The Advisory Committee particularly welcomes:

• comments on the preliminary recommendation
• the identification of factual inaccuracies
• additional relevant evidence.

Note that this document is not the Institute's formal guidance on this procedure. The recommendations are provisional and may change after consultation.

The process that the Institute will follow after the consultation period ends is as follows:

• The Advisory Committee will meet again to consider the original evidence and its provisional recommendations in the light of the comments received during consultation.
• The Advisory Committee will then prepare draft guidance which will be the basis for the Institute's guidance on the use of the procedure in the NHS in England, Wales and Scotland.

For further details, see the Interim Guide to the Interventional Procedures Programme, which is available from the Institute's website (www.nice.org.uk/ip).

Closing date for comments: 27 July 2004

Target date for publication of guidance: November 2004

Note that this document is not the Institute's guidance on this procedure. The recommendations are provisional and may change after consultation.

Current evidence on the safety and diagnostic yield¹ of wireless capsule endoscopy appears adequate to support the use of this procedure, provided that the normal arrangements are in place for consent, audit and clinical governance. However, the procedure's sensitivity, specificity and predictive value are not known.

Patients should have undergone other investigations, such as small-bowel contrast studies, before wireless capsule endoscopy is used. This is particularly important for patients who may have strictures (such as those with suspected Crohn's disease) because they are at a greater risk of delayed passage of the capsule, which causes small bowel obstruction and may necessitate laparotomy.

Obscure gastrointestinal bleeding is defined as bleeding of unknown origin that persists or recurs after a negative initial endoscopy (colonoscopy and/or upper gastrointestinal endoscopy). Diagnosis may be difficult because bleeding can often be slow and/or intermittent. Patients may experience prolonged blood loss, leading to iron deficiency (anaemia) and a feeling of tiredness.

Small intestinal bleeding can result from a number of conditions, including vascular lesions (angiodysplasia), small bowel tumours, coeliac disease and Crohn's disease (which may be suspected because of other symptoms).

There are several methods for evaluation of the small bowel including push enteroscopy (using a long tube through which images of the bowel's lining can be seen), intraoperative endoscopy and radiological small-bowel follow-through studies (in which the patient is required to drink barium and then have X-ray pictures taken of their abdomen at timed intervals). For most of these methods, the diagnostic accuracy (ability to correctly diagnose and exclude disease) is poor.

The patient swallows a small capsule, usually after an overnight fast. This capsule consists of a camera, a light source and a wireless circuit for the acquisition and transmission of signals. As the capsule moves through the gastrointestinal tract, images are transmitted to a data recorder, worn on a belt outside the body. These data are transferred to a computer for interpretation. The capsule is then passed in the patient's stool and not used again.

This procedure allows for the end-to-end visualisation of the small bowel. However, the presence of a motility disorder or stricture may preclude successful investigation.

In obscure gastrointestinal bleeding, the published evidence suggests that wireless capsule endoscopy can detect a bleeding source in 31-76% (4/13-25/33) of patients with obscure gastrointestinal bleeding. In all studies, wireless capsule endoscopy had a higher diagnostic yield (proportion of patients identified with an apparent abnormality) than the comparator test. However, in most cases, patients had undergone extensive prior investigations, which are likely to decrease the apparent diagnostic yield for the comparator procedures. It is also not possible to determine the relative diagnostic performance (ability to detect correctly both the presence and absence of disease) of wireless capsule endoscopy compared with alternative conventional diagnostic tests. Several studies reported that capsule endoscopy findings had changed patient management, but limited details were given as to whether change in management improved health outcomes. For more details, refer to the Sources of evidence (see Appendix).

For suspected Crohn's disease, the evidence suggests that wireless capsule endoscopy identifies small bowel lesions suggestive of Crohn's disease in 43-71% (9/21-12/17) of patients with normal findings on conventional tests. Three studies reported that capsule endoscopy findings had changed patient management, with two studies reporting clinical improvement in 83-100% (10/12-9/9) of patients. The available evidence, however, is not of sufficient quantity and quality to determine the relative diagnostic performance of wireless capsule endoscopy compared with alternative conventional diagnostic tests in diagnosing unselected patients with suspected Crohn's disease. For more details, refer to the Sources of evidence (see Appendix).

The Specialist Advisors noted a lack of comparative data in relation to existing technology. They also considered that the main indications for the procedure and its place in diagnosis were still to be defined.

No significant complications were reported in the studies. The most commonly reported adverse events associated with the procedure were abdominal pain, nausea and vomiting. Delayed passage of the capsule was also reported in a number of studies and, in the majority of cases, resolved without specific treatment. In a study of 200 patients performed to assess the complications associated with the use of capsule endoscopy, six (3%) patients had complications associated with the procedure. These included one patient who was unable to swallow the capsule, one patient who inadvertently aspirated the capsule and two patients who experienced delayed passage and had to have surgery to remove the capsule. For more details, refer to the Sources of evidence (see Appendix).

The Specialist Advisors considered this to be a safe procedure. They noted that the most likely adverse event was lodgement of the capsule in narrowed areas of the small bowel, causing bowel obstruction. One Advisor commented that this complication was more likely in patients with suspected Crohn's disease than in patients with obscure gastrointestinal bleeding.

The following document, which summarises the evidence, was considered by the Interventional Procedures Advisory Committee when making its provisional recommendations.

• Interventional procedure overview of wireless capsule endoscopy, January 2004

Available from: www.nice.org.uk/ip216overview