Predictors for choledocholitiasis in patients undergoing endoscopic ultrasound.

AIM: Biliary lithiasis is common in most western countries. Symptomatic patients will also have choledocholithiasis in 10% of the cases. For patients with intermediate probability of CBD stones, the recommended imaging studies are endoscopic ultrasound (EUS) or MRCP. This study aims to identify early factors that can be used as predictors for the presence of CBD stones, and by that to find which patient should undergo ERCP without an early EUS.

METHODS: This is a retrospective cohort study including all patients who underwent EUS for suspected choledocholithiasis at the Soroka University Medical Center (SUMC) in the years 2009-2014. Data collection was performed by manual surveillance of patients' computerized files and data gathering after approval by the Soroka Institutional Review Board Results: One hundred seventy-five (175) patients were included in the study. The average age was 57, and 111 patients were women (64.2%). Sixty-two patients (35%) had common bile duct stones by EUS and underwent an ERCP. Eighty-two percent of those 62 patients were found to have CBD stones at ERCP. Patients found positive for CBD stones by EUS were older than those who were negative (52 vs. 71 respectively, p < .001). These patients were also found to have a higher prevalence of ischemic heart disease and congestive heart failure. Common bile duct dilatation ≥8mm and gallstones presence in abdominal ultrasonography were more common in patients found positive for CBD stones by EUS than in those who were found negative (45% vs. 24% p < .05, and 81% vs. 66% p < .05, respectively). Alkaline phosphatase (ALP) serum levels higher than 300 IU/L were found to be the only independent predictor for the existence of CBD stones (OR = 2.98, p = .001(. When ALP serum levels lower than 150 IU/L or GGT lower than 150 IU/L were measured, the probability of having CBD stones was low (NPV of 90% and 87%, respectively).

CONCLUSIONS: ALP serum levels higher than 300 IU/L are an independent predictor for the presence of CBD stones. EUS is an excellent screening tool for choledocholithiasis before performing ERCP. In most patients who undergo an early EUS, a subsequent diagnostic ERCP will not be needed.