Su1735 Risk Factors Related to Open Converted Cholecystectomy in Patients With Cholelithiasis After Endoscopic Removal of Choledocholithiasis Yong-Hwan Kwon*, Chang-MIN Cho, MIN Kyu Jung, Seongwoo Jeon Internal Medicine, Kyungpook National University medical center, Daegu, Republic of Korea Background and aims: Laparoscopic cholecystectomy (LC) has been established as the gold standard management for symptomatic patients with cholelithiasis. Sometimes, it is inevitable to convert to open cholecystectomy (OC) in patients who planned to LC. In patient with GB and CBD stones, endoscopic removal of CBD stone may cause inflammation that is associated with adhesion adjacent to gallbladder. It is related to open converted cholecystectomy (OCC). However, there are few studies about which factors related to endoscopic retrograde cholangiopancreatography (ERCP) may influence conversion to OC. The purpose of this study was to evaluate the risk factors related with OCC in patients who were planned to LC after endoscopic removal of choledocholithiasis (ERC). Patients and Methods: The data for all patients who underwent LC or OCC after endoscopic removal of bile duct stone at our institution between January 2001 and December 2010 were retrospectively reviewed. Factors predictive for conversion were analyzed. Results: Three hundred seven patients underwent endoscopic removal of choledocholithiasis followed by scheduled LC. Among them, 48 patients (15.6%) needed conversion to OC. The most common cause of conversion to OC was anatomical adhesion in operation field (37.5%). Cholecystitis (p!0.005), percutaneous transhepatic biliary drainage (PTBD) or percutaneous gallbladder drainage (PTGBD) (pZ0.005), mechanical lithotripsy (p!0.005), multiple stones (pZ0.011), and multiple endoscopic trials of stone removal (pZ0.006) were significantly related to conversion in univariate analysis. In multivariate analysis, cholecystitis (OR 2.844, 95%CI 1.301-6.214, pZ0.009), mechanical lithotripsy (OR 6.881, 95%CI 2.142-22.109, p!0.005), multiple stones (OR 2.308, 95%CI 1.1614.590, pZ0.017), and multiple trials of stone removal (OR 3.180, 95%CI 1.0209.916, pZ0.046) were associated with OCC. Analyzing the OCC-related risk factors according to the duration from ERC to LC, mechanical lithotripsy (OR 16.161, 95% CI 2.971-87.895, p!0.005), multiple stones (OR 3.400, 95%CI 1.095-10.556, pZ0.034), and multiple trials of ERC (OR 8.632, 95%CI 1.072-69.481, pZ0.043) were significantly related to OCC within 2 weeks. However, there was no significant risk factor for conversion to OC after 2 weeks. Conclusions: In patients who had combined choledocholithiasis and cholelithiasis, considering risk factors related to open conversion cholecystectomy will be helpful determining the timing of LC, and if the patients had these endoscopic related risk factors, it is better to delay LC after 2 weeks from ERCP. Table 1. The risk factors of LC and OC after ERC www.giejournal.org LC (N[259) OC (N[48) Univariate P value Multivariate P value Age (years old) 61.9 15.2 60.8 16.1 0.665 Gender 0.076 Male 151 (58.3%) 35 (72.9%) Female 108 (41.7%) 13 (27.1%)