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

Background and Aims: Although 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 of >6 mm objectively) from 2 academic medical centers without active pancreaticobiliary disease or significantly elevated liver function test results 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 of ≥70 years (odds ratio [OR], 3.7; 95% confidence interval [CI], 1.5-10.0), non–biliary-type abdominal pain without chronic pain (OR, 6.1; 95% CI, 2.3-17.3), CBD diameter of ≥15 mm or ≥17 mm with cholecystectomy (OR, 6.9; 95% CI, 2.7-18.7), and prior ERCP (OR, 6.8; 95% CI, 2.1-22.5). A point-based novel clinical prediction model was created: age of ≥70 years = 1, non–biliary-type abdominal pain without chronic pain = 2, prior ERCP = 2, and CBD dilation = 2. A score of <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 of ≥4 was >90% specific for the presence of significant pathology. Conclusions: 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 one-third of patients.