Background: EGD is the gold standard for the screening and surveillance of esophageal varices. A less invasive, safer and sedationless alternative procedure is needed.
Objective: To assess the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) as well as the beyond the chance agreement (kappa index), of string capsule endoscopy (SCE) in the diagnosis of esophageal varices.
Methods: Cirrhotic patients underwent string capsule endoscopy (SCE) and EGD for screening and surveillance purposes. Varices were graded at EGD and SCE as small, medium and large. Descriptors at SCE were added as follows: PLUS, for the presence of red wale signs or, MINUS for their absence, irrespective of the estimated variceal size. Clinically significant varices were defined by their size (medium/large at either EGD or SCE) and/or, the PLUS descriptor irrespective of the estimated size at SCE. Sensitivity, specificity, PPV, NPV, accuracy and kappa index were calculated. Procedure time, procedure-related discomfort and patient's preference were documented.
Results: 100 patients (33 for screening and 67 for surveillance) were enrolled. The sensitivity and specificity of SCE for clinically significant varices when using the PLUS/MINUS descriptors were 82% and 90%, respectively with a PPV of 84% and NPV of 89% and a kappa of 0.73.
Conclusion: String capsule endoscopy had an acceptable sensitivity and specificity for the diagnosis of clinically significant esophageal varices but the lack of air insufflation still hampers its correlation with the grading used with EGD.
Keywords: cirrhosis; sensitivity; specificity; string capsule endoscopy; varices.