Clinical evaluation of the use of the M2A patency capsule system before a capsule endoscopy procedure, in patients with known or suspected intestinal stenosis

Background and Study Aim: The main complication of video capsule endoscopy (VCE) is the blocking of the capsule by a gastrointestinal stenosis. The "patency capsule" is a self-dissolving capsule that is the same size as the video capsule. It contains a radiofrequency identification (RFID) tag that allows it to be detected by a scanning device placed on the abdominal wall. When its passage is blocked by a stenosis, the patency capsule dissolves in 40-80 hours after ingestion. The aim of this study was to evaluate the usefulness of this system in patients with suspected intestinal stenosis but also requiring VCE. Patients and Methods: 22 patients (16 men; 46 18 years; 15 with diagnosed or suspected Crohn's disease, two with suspected intestinal tumor, and two on nonsteroidal anti-inflammatory drugs) were first investigated with an abdominal CT plus enteroclysis (entero-CT, n=15) or a small-bowel follow-through (SBFT, n=7). The patency capsule was then administered at around 09.00 to fasting patients. The presence of the patency capsule in the digestive tract was assessed 30 hours later using the hand-held scanner. When the patency capsule was detected, a plain abdominal film was obtained, and this was repeated every 24 hours until capsule expulsion. Results: At 30 hours after ingestion, the patency capsule was detected in 17 patients (72.3%): in the area of the small intestine (n=6) and in the colon (n=11). In all the patients in whom the capsule was blocked in the small intestine, the stenosis had been suspected on CT or SBFT. In three patients, the delay in progression of the patency capsule led to cancellation of the VCE procedure. In three patients, the patency capsule induced a symptomatic intestinal occlusion, which resolved spontaneously in one and required emergency surgery in two. Although these two patients would have been obliged to undergo operation for their primary disease in any case, the procedure had to be brought forward. In one patient, the capsule passed through the stenosis without symptoms. All patients in whom the progression of the patency capsule was delayed had an established or suspected diagnosis of Crohn ' s disease. Conclusions: The current technical development of the patency capsule limits its use in clinical practice, as it did not detect ste noses undiagnosed by CT or SBFT. The start of dissolution at 40 hours after ingestion is too slow to prevent episodes of intestinal occlusion. Patients with Crohn ' s disease are most likely to be at risk of blockage of progression of the capsule and should benefit from a CT investigation before VCE. However, a careful interview eliciting the patient ' s medical history and symptoms remains the most useful indicator with regard to suspicion of an intestinal stenosis.