Exploring the Utility of the Given Patency Capsule in Patients At Risk of Capsule Retention

Abstract

Background: Capsule retention (CR) is a concern when considering capsule endoscopy (CE) for patients with ‘high-risk’ indicators - Crohn's disease, obstructive symptoms, heavy NSAID usage, prior abdominal surgery or abnormal small bowel radiology. A prior patency capsule (PC) or small bowel x-ray (BFT) is prudent for these patients. However, a normal BFT does not exclude significant stricturing or capsule retention, and the utility of BFT in this context is in doubt. Method: We reviewed our experience with the PC and with BFT in patients at risk of CR. We reviewed the records of all patients referred for CE between July 2004 and August 2006. During this period, any patient considered high risk for CR received a PC prior to CE. An abdominal x-ray (AXR) 36 hrs after ingestion confirmed PC passage: if the PC was visible, gastrograffin was used to confirm position (small or large bowel); if the PC was retained in the small bowel, CE was not performed and a BFT was carried out. Results: In each case comparison was made between the PC result and any prior or subsequent radiology.324 patients were studied over 26 months. 275 (85%) low-risk patients did not receive a PC. There were no cases of CR at subsequent CE. 49 (15%) high-risk patients received a PC. The PC passed in 38 (77%) - at CE: 35 passed easily; 1 transient hold-up; 1 retained in stomach; 1 retained in small bowel (review of AXR showed PC in small bowel ie false -ve). 25 of 38 had prior radiology, with significant strictures in 3. PC retained in 11 (23%) with no resulting complications. 4 had no prior radiology: 1-subsequent BFT showed jejunal adhesions; 2-BFT showed TI Crohn's; 3-false + PC (retained PC actually calcified fibroid); 4-lost to follow up.5 had prior normal radiology: 1-subsequent BFT normal, repeat PC retained, CT enterography showed active ileal Crohn's; 2-PC in caecum ie false +; 3-subsequent BFT normal, awaiting repeat PC; 4-awaiting BFT; 5-lost to follow-up2 had prior minor abnormalities at radiology: 1 had tight strictures at DBE; 1 had tight ileal Crohn's stricture. Conclusions: 1. Patients without high-risk indicators for CR do not require a PC prior to CE. 2. The reliability of BFT for determining PC passage through the small bowel is poor. 3. In our experience, the PC can be used safely as a 1 st line investigation in patients with high-risk indicators for CR without a prior BFT. 4. Retention of the PC is highly suggestive of significant underlying pathology. PC use helps to avoid the inappropriate and potentially dangerous application of CE in these patients. 5. Interpretation of PC location on AXR can be difficult, and false positives or false negatives may result.