title: Safety and efficacy of the M2A patency capsule for diagnosis of critical intestinal patency: results of a prospective clinical trial.
abstract: OBJECTIVE
  The presence of a critical intestinal stricture is a contraindication for conventional capsule endoscopy for the risk of impaction. Prior assessment of intestinal patency can substantially minimize this risk. The aim of the present study was to assess the safety and efficacy of the M2A patency capsule (PC) for verification of intestinal strictures.
  
  
  METHODS
  The M2A PC consists of a biodegradable body surrounding a small radiofrequency identification (RFID) tag. This capsule was administered to patients with known or suspected intestinal strictures. Patency was verified if the capsule was excreted intact. The capsule disintegrated into small fragments and only the RFID tag was excreted if retained at the stricture beyond a stipulated time. The patency scanner was used to detect the RFID tag externally. The M2A video capsule (VC) was administered to patients who excreted the intact capsule.
  
  
  RESULTS
  Twenty-six patients with known or suspected intestinal strictures were administered the M2A PC. This included 16 (61%) patients with tuberculosis, eight (31%) with Crohn's disease, and one each of postoperative and malignant strictures. Eight capsules were excreted intact within 72 h and two at 109 and 110 h. Fifteen capsules disintegrated in the G(I) tract and one capsule was removed during surgery. No PC-related complications were noted. Six of the eight patients who tested positive for patency were tested with the regular M2A VC with normal excretion.
  
  
  CONCLUSIONS
  The M2A PC is a reliable indicator of functional patency in suspected or even known cases of intestinal stricture. It could be used prior to conventional capsule endoscopy to predict and minimize the risk of impaction.
authors.affiliation: Asian Institute of Gastroenterology, Hyderabad, Andhra Pradesh, India.
authors.forename: Rupa
authors.initials: R
authors.lastname: Banerjee
authors.forename: Prem
authors.initials: P
authors.lastname: Bhargav
authors.forename: Praveen
authors.initials: P
authors.lastname: Reddy
authors.forename: Rajesh
authors.initials: R
authors.lastname: Gupta
authors.forename: Sandeep
authors.initials: S
authors.lastname: Lakhtakia
authors.forename: Manu
authors.initials: M
authors.lastname: Tandan
authors.forename: Venkat G
authors.initials: VG
authors.lastname: Rao
authors.forename: Nageshwar D
authors.initials: ND
authors.lastname: Reddy
mesh_terms: D000328:Adult; D053704:Capsule Endoscopy / Q000009:adverse effects*; D005260:Female; D006801:Humans; D007415:Intestinal Obstruction / Q000175:diagnosis* / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D016896:Treatment Outcome