Evaluation of Small-Bowel Patency in Crohn's Disease: Prospective Study with a Patency Capsule and Computed Tomography

Abstract

Background and Purpose: Patency capsule (PC) examination is usually performed - previously to capsule endoscopy - to evaluate small-bowel patency in patients with established Crohn's disease (CD). The reported PC retention rate is significantly higher than expected. Our aims were to assess small-bowel patency, to determine the precise location of the retained PC in patients with CD, and to determine the false positive rate of evaluation with a radiofrequency identification tag (RFIT) scanner. Methods: This is a prospective single-center study including CD patients with clinical indication for small-bowel capsule endoscopy. PillCam® PC examination was performed on all patients to assess small-bowel patency. On all patients with a positive identification of the PC using an RFIT scanner, 30 h after ingestion, an abdominal CT was performed in order to identify its precise location. Results: Fifty-four patients were included. The PC retention rate, according to evaluation with the RFIT scanner, was 20% (in 11 patients) 30 h after ingestion. These patients were then submitted to abdominal CT, which revealed that there was small-bowel retention in 5 cases (9%). Higher CRP levels, penetrating disease, and a history of abdominal surgery were associated with an increased risk of PC retention (p = 0.007, p = 0.011, and p = 0.033, respectively). On multivariate analysis, there was an independent association between small-bowel PC retention and CRP levels >5 mg/dL (OR = 15.5; p = 0.03). Discussion: The small-bowel PC retention rate (9%) was considerably lower than those found in previous reports. Our results show that, with this protocol, the false-positive cases of RFIT scans or plain abdominal X-rays may be avoided. This may contribute to more extensive application of capsule endoscopy without the risk of small-bowel retention.