A novel capsule endoscopy for upper and mid-GI tract: the UMGI capsule | BMC Gastroenterology

Study design

This pilot study was a prospective, single-centered, blinded self-controlled study. The study protocol was approved by the Institutional Review Board of Changhai Hospital (Shanghai, China) and registered at ClinicalTrials.gov. with registration number NCT04329468. All enrolled subjects signed the informed consents according to the Helsinki Declaration.

Study patients

Patients aged from 18 to 80 years old and willing to undergo both UMGI capsule and EGD examination with or without gastrointestinal complaints were prospectively recruited in Changhai Hospital from March to August 2020, in which the asymptomatic subjects were healthy volunteers. Examination of UGI tract with/without small bowel were confirmed according to their clinical manifestations and requirements. Basic characteristics, gastrointestinal complaints, and Helicobacter pylori infection status were recorded. Patients with the following criteria were excluded: (1) those with suspected or known gastrointestinal stenosis, obstruction, fistula, or other risk factors for capsule retention; (2) metallic or electronic medical devices implanted; (3) those were pregnant or suspected of pregnancy; (4) unable to cooperate with the examination such as psychotics or in poor general condition of hemodynamic instability; and (5) those with any other contraindications to MCE or EGD procedure determined by endoscopists.

Study intervention

Each participant underwent UMGI capsule endoscopy followed by EGD within one week, and all endoscopy examinations were conducted before treatment of GI diseases. UMGI capsule was carried out by an endoscopist with an experience of more than 1000 cases of MCE procedures and a physician assisting in the control of detachable string. Standardized EGD examination with xylocaine spray for pharyngeal local anesthesia was performed by another well-trained endoscopist, who was blinded to the capsule findings. The final diagnosis was made by combining the results of both modalities. During these procedures, a designated researcher collected the relative data about all evaluation parameters.

UMGI capsule procedure

UMGI capsule endoscopy system (Ankon Technologies Co. Ltd, Shanghai, China) consists of a detachable string attached to the capsule and an upgraded MCE [13] with an adaptive frame rate of 8 frames per second, image resolution of 720 × 720 pixels, field of view of 150 degrees, and battery duration of more than 12 h. This hollow and thin string is composed of sterile and transparent latex for single use, 120 cm in length with a caudal suction cap. Capsule endoscopy is partially enclosed within the cap and can be detached from the string by injecting air with a sterile syringe [14].

After a standardized preparation regimen [15] (Bowel preparation: patients received 2 L polyethylene glycol 5 h before examination. Gastric preparation: patients ingested 400 mg simethicone suspension dissolved in 100 mL water 40 min before examination and drank 1000 mL of water 10 min before examination.), patients swallowed the capsule in left lateral position, allowing the capsule to be slowly pulled up and down in esophagus under string control for repeated observation of targeted areas under real-time viewing. Water ingestion would be repeated for adequate visualization of esophageal mucosa. After completing esophageal examination, the capsule entered the stomach and was lifted, rotated, advanced or returned to orderly observe gastric fundus, cardia, body, angulus, antrum and pylorus, controlled by external magnet robot [15]. When stomach examination was finished, magnetic steering was used to help the capsule pass through pylorus [16], and the string was tension-free during the process. After entering duodenum, the capsule was allowed to gradually travel down as far as the end part of duodenum and then be slowly pulled up by the string for complete viewing of duodenal mucosa. Detection of duodenal papilla and the reverse side of pylorus in duodenal bulb was tried within a maximum of three-time repeated viewing under the combined control of magnet and string, in which “360-degree automatic scanning” mode was used to help rotate the capsule. If mucus, bubbles or insufficient distension impeded the observation, a small amount of water ingestion and position changes in supine or right-lateral decubitus might be helpful and were allowed as needed. If discomfort caused by the string occurred, manipulator would slow down or stop the movement of the string and let the patients regulate their breath, and wait for the next right time unless the patients decided to quit the trial. Once completing duodenal examination, the capsule was separated from the string and proceeded with small-bowel examination (if needed) without external magnet force according to the standardized protocol (Fig. 1).

Study outcomes

The primary study outcome was technical success of UMGI capsule endoscopy, defined as successful repeated observation of esophagus, stomach, and duodenum and detachment of capsule from string after duodenal examination. Secondary outcomes included the visualization of UMGI tract, examination time, diagnostic yield, discomfort and adverse events associated with the procedure.

Visualization of esophagus was indicated by the detection of Z-line defined as at least one image of Z-line was obtained and circumferential viewing of Z-line (one quadrant; at least two quadrants; at least three quadrants; and all four quadrants) [14]. Visualization of gastric mucosa in each anatomical landmark was evaluated as good, moderate, and poor defined as 90–100%, 70–90% and < 70% of mucosa could be observed, respectively [5]. Visualization of duodenum was indicated by the detection of duodenal papilla and the reverse side of pylorus in duodenal bulb, and was graded as full, more than half and less than half being viewed [17]. Discomforts such as nausea, vomiting or cough were scored on a scale from 0 to 3 (0, none; 1, mild; 2, moderate; and 3, severe), and overall discomfort was graded using a scale of 0 to 10 (0, none; 10, severe) [14].

Statistical analysis

As a pilot study to evaluate the clinical utility of the UMGI capsule, sample size was not calculated. Quantitative data were presented as mean ± standard deviation (SD) or median and interquartile range (IQR), where appropriate, and categorical data were described as frequency (percentage). Statistical analyses were performed using SPSS software version 25.0 (IBM Corp, Armonk, NY, USA).