Clinical predictors of significant findings on EUS for the evaluation of incidental common bile duct dilation.

BACKGROUND AND AIMS: While endoscopic ultrasound(EUS) is highly accurate for the evaluation of common bile duct (CBD) dilation, the yield of EUS in patients with incidental CBD dilation is unclear.

METHODS: Serial patients undergoing EUS for incidental, dilated CBD (per radiologist, minimum >6mm objectively) from two academic medical centers, without active pancreaticobiliary disease or significantly elevated LFTs were evaluated. Multivariable logistic regression identified predictors of EUS with significant findings and a novel prediction model was derived from one center, internally validated with bootstrapping, and externally validated at the second center.

RESULTS: Of 375 patients evaluated, 31 (8.3%) had significant findings including 26 choledocholithiasis, 1 ampullary adenoma, and 1 pancreatic mass. Predictors of significant findings with EUS included: age ≥70(OR 3.7, 95CI 1.5-10.0), non-biliary-type abdominal pain without chronic pain(OR 6.1, 95CI 2.3-17.3), CBD diameter ≥15 mm or ≥17mm with cholecystectomy(OR 6.9, 95CI 2.7-18.7), and prior ERCP(OR 6.8, 95CI 2.1-22.5). A point-based novel clinical prediction model was created: age ≥70=1, non-biliary-type abdominal pain without chronic pain=2, prior ERCP=2, CBD dilation=2. A score <1 had 93% (development) and 100% (validation) sensitivity and predicted a <2% chance of having a significant finding in both cohorts while excluding the need for EUS in ∼30% of both cohorts. Conversely, a score >4 was >90% specific for the presence of significant pathology.

CONCLUSION: Less than 10% of patients undergoing EUS for incidental CBD dilation had pathologic findings. This novel, externally validated, clinical prediction model may reduce low-yield, invasive evaluation in nearly a third of patients.