Nationwide multicenter study on adverse events associated with a patency capsule: Additional survey of appropriate use of patency capsule study

Background and Aim: The PillCam patency capsule (PC) without a radio frequency identification tag was released to preclude retention of the small bowel capsule endoscope (CE) in Japan in 2012. We conducted a multicenter study to determine tag-less PC-related adverse events (AEs). Methods: We first conducted a retrospective survey using a standardized data collection sheet for the clinical characteristics of PC-related AEs among 1096 patients collected in a prospective survey conducted between January 2013 and May 2014 (Cohort 1). Next, we retrospectively investigated additional AEs that occurred before and after Cohort 1 within the period June 2012 and December 2014 among 1482 patients (Cohort 2). Results: Of the 2578 patients who underwent PC examinations from both cohorts, 74 AEs occurred among 61 patients (2.37%). The main AEs were residual parylene coating in 25 events (0.97%), PC-induced small bowel obstruction, suspicious of impaction, in 23 events (0.89%), and CE retention even after patency confirmation in 10 events (0.39%). Residual parylene coating was significantly associated with Crohn's disease (P < 0.01). Small bowel obstruction was significantly associated with physicians with less than 1 year of experience handling the PC and previous history of postprandial abdominal pain (P < 0.01 and P < 0.03, respectively). CE retention was ascribed to erroneous judgment of PC localization in all cases. Conclusions: This large-scale multicenter study provides evidence supporting the safety and efficiency of a PC to preclude CE retention. Accurate PC localization in patients without excretion and confirmation of previous history of postprandial abdominal pain before PC examinations is warranted (UMIN000010513).