String capsule endoscopy for screening and surveillance of esophageal varices in patients with cirrhosis

Novel Clinical Applications and Technical Developments in Video Capsule Endoscopy

Video capsule endoscopy is entering its third decade. After slow acceptance, it has become the gold standard in diagnosing small intestinal disorders. This article summarizes new practical applications for capsule endoscopy outside the small intestine. From 2 randomized controlled trials, it is becoming clear that it has a role in the management of patients with hematemesis and nonhematemesis bleeding. Under active investigation are novel applications of capsule technology, including the potential ability to sample luminal contents or tissue, self-propelled capsules, incorporation of other imaging techniques beyond white light, such as ultrasound and fluorescents, and the possibility of drug delivery.

Better view by detachable string magnetically controlled capsule endoscopy for esophageal observation: a retrospective comparative study

Magnetically controlled capsule endoscopy (MCE) system has been used to screen gastric lesions. However, the visualization performance of MCE in the esophagus has not been investigated systematically. String method improved the ability of capsule endoscopy (CE) for esophageal observing; however, the string attachment is complicated and cannot be detached with the CE inside the esophagus. We used a modified string, called detachable string attached to MCE. The aim of the study was to compare the observation performance of MCE with and without the detachable string. A total of 238 participants with upper gastrointestinal symptoms and a healthy check who refused esophagogastroduodenoscopy examination were retrospectively divided into the detachable string MCE group and the MCE alone group from June 2016 to May 2018. A suction cap with a thin, hollow string was attached to the MCE system in the detachable string group. Circumferential visualization of the esophagus including the upper, middle, and lower esophagus and Z-line, and esophageal focal lesion, as well as the recording time, safety and tolerability of the procedure, were assessed. The circumferential visualization of the upper, middle, and lower esophagus and Z-line was more efficient in the detachable string MCE group than in the MCE alone group (P < 0.001). In all, 31 esophageal lesions were detected in the detachable string MCE group, which was more than that in the MCE alone group (10, P < 0.001). The mean recording time was 305 seconds in the string MCE group, which was longer than that in the MCE alone group (48.5 seconds, P < 0.001). In seven participants (6.1%) in the detachable string MCE group, the capsule could not be separated from the string. Detachable string MCE showed better performance in terms of observation of the esophagus. Detachable string MCE can be used to screen for esophageal diseases as an alternative method in the future.

Current and Future Use of Esophageal Capsule Endoscopy

Capsule endoscopy can be a diagnostic option for patients with esophageal diseases who cannot tolerate esophagogastroduodenoscopy.Functional modifications of the capsule allow for thorough examination of the esophagus. Esophageal capsule endoscopy has so farfailed to show sufficient performance to justify the replacement of traditional endoscopy for the diagnosis of esophageal diseasesbecause the esophagus has a short transit time and common pathologies appear near the esophagogastric junction. However,technological improvements are being introduced to overcome the limitations of capsule endoscopy, which is expected to become agood alternative to conventional endoscopy.

Νon-invasive screening for esophageal varices in patients with liver cirrhosis

Esophageal varices are one of the main complications of liver cirrhosis. Upper gastrointestinal endoscopy is the gold standard for the detection of esophageal varices. Many less invasive methods for screening of varices have been investigated and the most recent Baveno VI guidelines suggest that endoscopy is not necessary in patients with liver stiffness <20 kPa and platelets >150,000/μL. A critical review of the literature was performed concerning non-invasive or minimally invasive methods of screening for esophageal varices. Liver and spleen elastography, imaging methods including computed tomography, magnetic resonance imaging and ultrasound, laboratory tests and capsule endoscopy are discussed. The accuracy of each method, and its advantages and limitations compared to endoscopy are analyzed. There are data to support the Baveno VI guidelines, but there is still a lack of large prospective studies and low specificity has been reported for the liver stiffness and platelet count combination. Spleen elastography has shown promising results, as there are data to support its superiority to liver elastography, but it needs further assessment. Computed tomography has shown high diagnostic accuracy and can be part of the diagnostic work up of cirrhotic patients in the future, including screening for varices.

Use of Wireless Capsule Endoscopy for the Diagnosis and Grading of Esophageal Varices in Patients With Portal Hypertension: A Systematic Review and Meta-Analysis

INTRODUCTION

Esophageal variceal bleeding is a severe complication of portal hypertension with significant morbidity and mortality. Although traditional screening and grading of esophageal varices has been performed by endogastroduodenoscopy (EGD), wireless video capsule endoscopy provides a minimally invasive alternative that may improve screening and surveillance compliance.

AIM OF THE STUDY

The aim of the study was to perform a systematic review and structured meta-analysis of all eligible studies to evaluate the efficacy of wireless capsule endoscopy for screening and diagnosis of esophageal varices among patients with portal hypertension.

METHODS

Searches of PubMed, EMBASE, Web of Science, and the Cochrane Library databases were performed through December 2015. Bivariate and hierarchical models were used to compute the pooled sensitivity and specificity, and to plot the summary receiver operating characteristics curve with summary point and corresponding 95% confidence region. Bias of included studies was assessed using the quality assessment of diagnostic accuracy studies-2.

RESULTS

Seventeen studies from 2005 to 2015 were included in this meta-analysis (n=1328). The diagnostic accuracy of wireless capsule endoscopy in the diagnosis of esophageal varices was 90% [95% confidence interval (CI), 0.88-0.93]. The diagnostic pooled sensitivity and specificity were 83% (95% CI, 0.76-0.89) and 85% (95% CI, 0.75-0.91), respectively. The diagnostic accuracy of wireless capsule endoscopy for the grading of medium to large varices was 92% (95% CI, 0.90-0.94). The pooled sensitivity and specificity were 72% (95% CI, 0.54-0.85) and 91% (95% CI, 0.86-0.94), respectively, for the grading of medium to large varices. The use of capsule demonstrated only mild adverse events. A sensitivity analysis limited to only high quality studies revealed similar results.

DISCUSSION

Wireless esophageal capsule endoscopy is well tolerated and safe in patients with liver cirrhosis and suspicion of portal hypertension. The sensitivity of capsule endoscopy is not currently sufficient to replace EGD as a first exploration in these patients, but given its high accuracy, it may have a role in cases of refusal or contraindication to EGD.

Capsule endoscopy for the diagnosis of oesophageal varices in people with chronic liver disease or portal vein thrombosis

BACKGROUND

Current guidelines recommend performance of oesophago-gastro-duodenoscopy at the time of diagnosis of hepatic cirrhosis to screen for oesophageal varices. These guidelines require people to undergo an unpleasant invasive procedure repeatedly with its attendant risks, despite the fact that half of the people do not have identifiable oesophageal varices 10 years after the initial diagnosis of cirrhosis. Video capsule endoscopy is a non-invasive test proposed as an alternative method for the diagnosis of oesophageal varices.

OBJECTIVES

To determine the diagnostic accuracy of capsule endoscopy for the diagnosis of oesophageal varices in children or adults with chronic liver disease or portal vein thrombosis, irrespective of the aetiology. To investigate the accuracy of capsule endoscopy as triage or replacement of oesophago-gastro-duodenoscopy.

SEARCH METHODS

We searched the Cochrane Hepato-Biliary Group Diagnostic Test Accuracy Studies Register (October 2013), MEDLINE (Ovid SP) (1950 to October 2013), EMBASE (Ovid SP) (1980 to October 2013), ACP Journal Club (Ovid SP) (1991 to October 2013), Database of Abstracts of Reviews of Effects (DARE) (Ovid SP) (third quarter), Health Technology Assessment (HTA) (Ovid SP) (third quarter), NHS Economic Evaluation Database (NHSEED) (Ovid SP) (third quarter), and Science Citation Index Expanded (SCI-EXPANDED) (ISI Web of Knowledge) (1955 to October 2013). We applied no language or document type restrictions.

SELECTION CRITERIA

Studies that evaluated the diagnostic accuracy of capsule endoscopy for the diagnosis of oesophageal varices using oesophago-gastro-duodenoscopy as the reference standard in children or adults of any age, with chronic liver disease or portal vein thrombosis.

DATA COLLECTION AND ANALYSIS

We followed the available guidelines provided in the Cochrane Handbook for Diagnostic Test of Accuracy Reviews. We calculated the pooled estimates of sensitivity and specificity using the bivariate model due to the absence of a negative correlation in the receiver operating characteristic (ROC) space and of a threshold effect.

MAIN RESULTS

The search identified 16 eligible studies, in which only adults with cirrhosis were included. In one study, people with portal thrombosis were also included. We classified most of the studies at high risk of bias for the 'Participants selection' and the 'Flow and timing' domains. One study assessed the accuracy of capsule endoscopy for the diagnosis of large (high-risk) oesophageal varices. In the remaining15 studies that assessed the accuracy of capsule endoscopy for the diagnosis of oesophageal varices of any size in people with cirrhosis, 936 participants were included; the pooled estimate of sensitivity was 84.8% (95% confidence interval (CI) 77.3% to 90.2%) and of specificity 84.3% (95% CI 73.1% to 91.4%). Eight of these studies included people with suspected varices or people with already diagnosed or even treated varices, or both, introducing a selection bias. Seven studies including only people with suspected but unknown varices were at low risk of bias; the pooled estimate of sensitivity was 79.7% (95% CI 73.1% to 85.0%) and of specificity 86.1% (95% CI 64.5% to 95.5%). Six studies assessed the diagnostic accuracy of capsule endoscopy for the diagnosis of large oesophageal varices, associated with a higher risk of bleeding; the pooled sensitivity was 73.7% (95% CI 52.4% to 87.7%) and of specificity 90.5% (95% CI 84.1% to 94.4%). Two studies also evaluated the presence of red marks, which are another marker of high risk of bleeding; the estimates of sensitivity and specificity varied widely. Two studies obtained similar results with the use of a modified device as index test (string capsule). Due to the absence of data, we could not perform all planned subgroup analyses. Interobserver agreement in the interpretation of capsule endoscopy results and any adverse event attributable to capsule endoscopy were poorly assessed and reported. Only four studies evaluated the interobserver agreement in the interpretation of capsule endoscopy results: the concordance was moderate. The participants' preferences for capsule endoscopy or oesophago-gastro-duodenoscopy were reported differently but seemed in favour of capsule endoscopy in nine of 10 studies. In 10 studies, participants reported some minor discomfort on swallowing the capsule. Only one study identified other significant adverse events, including impaction of the capsule due to previously unidentified oesophageal strictures in two participants. No adverse events were reported as a consequence of the reference standard.

AUTHORS' CONCLUSIONS

We cannot support the use of capsule endoscopy as a triage test in adults with cirrhosis, administered before oesophago-gastro-duodenoscopy, despite the low incidence of adverse events and participant reports of being better tolerated. Thus, we cannot conclude that oesophago-gastro-duodenoscopy can be replaced by capsule endoscopy for the detection of oesophageal varices in adults with cirrhosis. We found no data assessing capsule endoscopy in children and in people with portal thrombosis.

String esophageal capsule endoscopy with real-time viewing improves visualization of the distal esophageal Z-line: a prospective, comparative study

OBJECTIVE

Esophageal capsule endoscopy (ECE) is relatively limited because of poor visualization of the distal esophagus. This study aimed to investigate whether string esophageal capsule endoscopy with real-time viewing (SECE+RTV) could improve the Z-line viewing of the distal esophagus as compared with conventional ECE.

METHODS

Thirty healthy volunteers, aged 20-45 years, were recruited and underwent SECE+RTV and ECE sequentially. The main outcome measures included grade of air-bubble and saliva interference, success rate of Z-line viewing (frequency of visualizing at least three quadrants), and frame number of images captured on the Z-line.

RESULTS

SECE+RTV showed a significantly greater percentage of no or mild air-bubble/saliva interference at the gastroesophageal junction [SECE+RTV vs. ECE, 90.0% (27/30) vs. 10.0% (3/30), P<0.001]. SECE+RTV had a significantly greater frame number of images captured on the Z-line (154.4±6.3 vs. 46±5.1, P<0.001). Moreover, SECE+RTV had significantly greater percentages of at least two quadrants [100.0% (30/30) vs. 80.0% (24/30), P<0.001] and at least three quadrants [90.0% (27/30) vs. 36.7% (11/30), P<0.001] of Z-line visualization.

CONCLUSION

Compared with ECE, SECE+RTV provides a better view of the distal esophagus in healthy individuals.