Detachable String Magnetically Controlled Capsule Endoscopy for Detecting High-risk Varices in Compensated Advanced Chronic Liver Disease (CHESS1801): A Prospective Multicenter Study

The presence of gastroesophageal varices (GEV) is a common and serious complication of compensated advanced chronic liver disease (cACLD).1-3 GEV hemorrhage is associated with a six week mortality rate of between 15% and 25%.2,3 In order to prevent variceal hemorrhage, screening and surveillance aims to detect high-risk varices (HRV) and determine the need for primary preventative therapy.2,3 Esophagogastroduodenoscopy (EGD) is therefore an important part of the diagnostic work-up in patients with cACLD, serving as the gold standard to diagnose HRV.2,3 However, EGD is invasive and poorly tolerated, with many patients needing intravenous sedatives or general anesthesia. Although EGD with sedation relieves patients' anxiety and discomfort and reduces the potential for physical injury during the procedure, it incurs additional risks of cardiopulmonary adverse events.4 Consequently, patients may decline a screening procedure if they are stable and asymptomatic.

Non-invasive methods for detection of cACLD are being explored.5-13 Although preliminary research is encouraging, these techniques predict the presence, rather than confirm or assess the size, of GEV. By contrast, capsule endoscopy is a non-invasive alternative which also allows direct visualization of GEV.14 A number of well-conducted trials15-19 suggest that EGD and capsule endoscopy may be equivalent in terms of accuracy in the identification and grading of varices. However, concerns remain that the quality of examination may be adversely affected by the uncontrolled and sometimes rapid transit of the capsule through the esophagus.20 String capsule endoscopy was introduced to address this concern by providing control of capsule movement as well as real-time visualization.21 However, this technique is limited by the inability to detach the string from the capsule. Thus, observation of the fundus, one of the predilection sites of varices, is impossible and retrieval of the capsule from the esophagus causes discomfort.

Magnetically controlled capsule endoscopy (MCCE), a novel modality, was developed and approved by the China Food and Drug Administration in 2013.22 Our previous studies initially demonstrated that MCCE was comparable in accuracy to EGD for gastric examination.22,23 Furthermore, it has several strengths including non-invasiveness, no sedation requirement, and easy operation.22,23 We have since combined an innovative detachable string system with the MCCE (detachable string magnetically controlled capsule endoscopy (DS-MCCE)) and carried out a pilot study showing that DS-MCCE was safe and feasible both in healthy volunteers and patients with suspected esophageal disease.24 Moreover, successful detachment of the capsule from the string avoids the discomfort of retrieving the entire capsule from the mouth and allows subsequent investigation of the gastric cardia and fundus. To our knowledge, the diagnostic accuracy of HRV, comfort and safety of DS-MCCE in patients with cACLD have not been explored in a large-scale trial. This prospective, multicenter study aimed to assess the accuracy, patient's satisfaction, and safety of DS-MCCE for detecting HRV in well-characterized patients with cACLD.