Asymptomatic bile duct stones: selection criteria for intravenous cholangiography and/or endoscopic retrograde cholangiography prior to laparoscopic cholecystectomy.

OBJECTIVE: Routine use of endoscopic retrograde cholangiography (ERC) and/or intravenous cholangiography (IVC) or magnetic resonance cholangiopancreatography (MRCP) before laparoscopic cholecystectomy (LC) is not cost-effective. The objective of this study was to determine precise and easily applicable criteria to select patients who should undergo IVC, MRCP and/or ERC before LC.

DESIGN AND METHODS: Prospectively collected data from 74 consecutive patients who were diagnosed with asymptomatic common bile duct stones (CBDS) before undergoing LC, were compared with data from 74 matched controls without CBDS. Using the chi2 test, those variables were identified which were significantly related to the presence of CBDS. These were inserted into a logistic multiple regression model and, by means of conditional regression analysis, each variable was assigned a score from -2 to +4 proportional to the odds ratio. By adding up the scores obtained, a classification was made as to high, medium and low CBDS risk.

RESULTS: As a result, 51 patients were found to be low-risk cases, 53 medium-risk and 44 high-risk. Assuming no further assessment of the bile duct needed to be carried out in low-risk patients, an IVC or MRCP in those at medium risk and an ERC in those at high risk, a calculation was made of the positive predictive value and the sensitivity of the system proposed. The positive predictive value and the sensitivity of the procedure were calculated as being greater than 90%.

CONCLUSIONS: This predictive system for the risk of CBDS allows the selective use of ERC, IVC and MRCP to ensure a high yield and improve cost-effectiveness. A controlled prospective study will verify these results.