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.