Management of suspected common bile duct stone: diagnostic yield of current guidelines

Background: The American Society for Gastrointestinal Endoscopy (ASGE) has recently published a guideline for suspected CBDS with the intention of reducing unnecessary ERCP and thereby complications. The aim of this study was to assess the diagnostic efficacy of the ASGE guideline. Methods: Data of patients who underwent ERCP with suspected CBDS were analyzed retrospectively. Patients were classified into high, intermediate and low risk groups based on predictors that have been suggested by the ASGE. Very strong predictors of the presence of ductal stones included: CBDS on transabdominal ultrasonography (US), clinical ascending cholangitis or total bilirubin (TBIL) >4 mg/dL). Strong predictors included dilated CBD >6 mm on US with gallbladder in situ and TBIL level of 1.8-4.0 mg/dL whereas moderate predictor included abnormal liver biochemical test other than bilirubin, age more than 55 years and clinical findings of biliary pancreatitis. Results: Of 888 enrolled patients, 704 had CBDS demonstrated by ERCP and the remainder did not. All very strong and strong predictors were found to be significantly higher among patients who had CBDS. Detection of CBDS by ultrasonography and a dilated common biliary duct were observed to be independent risk factors associated with the existence of CBDS. The high risk group had a high (86.7%) positive predictive value (PPV), however, sensitivity and specificity were observed to be moderate (67.8% and 60.3% respectively). PPV was 67.9% in the intermediate risk group and the sensitivity and specificity were very low (31.9% and 42.3%). Discussion: The probability of CBDS was observed to be high in the intermediate and high risk groups. However due to low sensitivity and specificity values, the ASGE guideline needs additional or different predictors.