Common bile duct stones complicate cholelithiasis in 10 to 15 percent of cases. Most authorities believe ductal stones should be removed because of possible complications, including cholangitis and acute pancreatitis. The ability to predict the presence or absence of bile duct stones would be helpful in the management of these patients. Because of new diagnostic and therapeutic approaches, such as endoscopic retrograde cholangiopancreatography (ERCP), endoscopic ultrasonography and laparoscopic surgery, Prat and associates conducted a study to identify predictors of common bile duct stones in patients with biliary symptoms.

The 880 patients in the prospective study had been referred for endoscopic ultrasonography for the evaluation of common bile duct stones. This procedure is considered the gold standard for the diagnosis of common bile duct stones. The prevalence of choledocholithiasis in the study population was 18.8 percent (166 of 880 patients). In patients under age 70, the prevalence of choledocholithiasis was 14 percent; in patients over 70, the prevalence was 32 percent.

Data analyses revealed that independent predictive variables for the presence of choledocholithiasis in patients younger than 70 years were an elevated (more than seven times normal) g-glutamyl transferase (GGT) level, a pathologic gallbladder and an abnormal common bile duct (dilated or with an intraluminal hyperechoic image on transabdominal ultrasound). In patients older than 70 years, independent predictors were elevated GGT, fever and a “suspect” common bile duct.

The authors conclude that screening of patients at risk for choledocholithiasis can be done using the three predictive criteria according to the patient's age. In patients undergoing cholecystectomy, two predictors (common bile duct size and GGT level) may be useful for screening.