Proposed criteria for preoperative endoscopic retrograde cholangiography in candidates for laproscopic cholecystectomy

Background: There has been a dramatic increase in the number of endoscopic retrograde cholangiograms (ERC) performed on patients who are candidates fo r laparoscopic cholecystectomy (LC). The majority of these procedures resul t in normal findings. This study is an attempt to determine useful clinical criteria and strategy for predicting the presence or absence of common bil e duct stones (CBDS) and the need for ERC in patients who are candidates fo r LC. Methods: The observational portion of this study explored laboratory and ul trasound data from 134 consecutive patients who had undergone preoperative ERC, followed by LC, over a 4-year period. The data were then analyzed by m ultivariate logistic regression to determine the best models for predicting the presence or absence of stones in the common bile duct. Models using ga mma glutamyl transpeptidase (GGT), alkaline phophatase (AP), common bile du ct diameter (CBDIA), and amylase(AMY) were then evaluated retrospectively i n 36 additional patients (validation group). Results: A model based on GGT and common bile duct diameter as positive pre dictors and amylase as a negative predictor correctly classified 78% of the patients in the validation group. This model resulted in a negative predic tive value (NPV), positive predictive value (PPV), sensitivity, and specifi city of 0.88, 0.68, 0.87, and 0.71, respectively. The model utilizing AP wa s almost as effective. This model resulted in a NPV, PPV, sensitivity, and specificity of 0.83, 0.67, 0.80, and 0.71, respectively. Conclusions: Although a number of laboratory values and imaging techniques correlate with the presence or absence of CBDS, our study confirms that ind ividually they have poor predictive value. Our data and models suggest that elevated serum amylase is a negative predictor for CBDS. Elevated GGT and/ or AP with widened CBDIA and normal AMY strongly suggest the presence of CB DS and the need for preoperative ERC. Elevated GGT, AP, or widened CBDIA wi th elevated amylase, in the absence of clinical. pancreatitis, may suggest that small stones have passed through the ampulla of Vater and that the CBD is generally cleared-of stones.