Accuracy of ASGE high-risk criteria in evaluation of patients with suspected common bile duct stones.

BACKGROUND AND AIMS: ERCP is recommended for patients considered high risk for choledocholithiasis after biochemical testing and abdominal US. Our aim was to determine whether the American Society for Gastrointestinal Endoscopy (ASGE) guidelines accurately select patients for whom the risk of ERCP is justified.

METHODS: Consecutive patients hospitalized with suspected choledocholithiasis at Sir Run Run Shaw Hospital who received biochemical testing, abdominal US, and definitive testing for choledocholithiasis (MRCP, EUS, ERCP, intraoperative cholangiogram, and/or common bile duct [CBD] exploration) were identified. Patients with choledocholithiasis on abdominal US, with bilirubin levels >4 mg/dL (normal values <1.2 mg/dL), bilirubin levels ≥1.8 mg/dL plus a dilated CBD and/or clinical cholangitis were considered high risk per ASGE guidelines.

RESULTS: Of 2724 patients with suspected choledocholithiasis, 1171 (43%) met high-risk criteria. Definitive testing (MRCP in 2442 [90%], EUS in 67 [2%], ERCP in 659 [24%], intraoperative cholangiogram in 229 [8%], and CBD exploration in 447 [16%]) revealed choledocholithiasis in 1076 [40%] patients. The specificity of the ASGE high-risk criteria was 74% (95% confidence interval [CI], 72%-77%) and positive predictive value was 64% (95% CI, 61%-67%). Using a more restrictive criteria (choledocholithiasis on abdominal US, bilirubin >4 mg/dL plus dilated CBD) improved the specificity to 94% (95% CI, 93%-95%) and positive predictive value to 85% (95% CI, 82%-88%). Doubling or more of bilirubin to >4 mg/dL and ≥1.8 mg/dL at second testing had specificities of 98% (95% CI, 96%-99%) and 95% (95% CI, 93%-96%), with positive predictive values of 62% (95% CI, 48%-76%) and 54% (95% CI, 44%-65%), respectively.

CONCLUSIONS: Although ASGE high-risk criteria demonstrated >50% probability of the patient having choledocholithiasis, more than a third of the patients would receive diagnostic ERCPs. Criteria with choledocholithiasis on abdominal US and/or bilirubin levels >4 mg/dL plus a dilated CBD showed higher specificity and positive predictive value.