Risk factors for the development of post-endoscopic retrograde cholangiopancreatography pancreatitis in patients with asymptomatic common bile duct stones

BACKGROUND: Previous studies have revealed that patients with asymptomatic common bile duct (CBD) stones are at a high risk of developing post-endoscopic retrograde cholangiopancreatography (ERCP) pancreatitis (PEP). However, no studies to date have addressed the risk factors for PEP in patients with asymptomatic CBD stones. AIM: To examine the risk factors for PEP in patients with asymptomatic CBD stones. METHODS: Using medical records of three institutions in Japan for 6 years, we identified a total of 1135 patients with choledocholithiasis including 967 symptomatic patients and 168 asymptomatic patients with native papilla who underwent therapeutic ERCP. We performed univariate and multivariate analyses to examine the risk factors for PEP in the 168 patients with asymptomatic CBD stones. RESULTS: The overall incidence rate of PEP in all the patients with during study period was 4.7% (53/1135). Of the 168 patients with asymptomatic CBD stones, 24 (14.3%) developed PEP. In univariate analysis, precut sphincterotomy (P = 0.009) and biliary balloon sphincter dilation (P = 0.043) were significant risk factors for PEP. In multivariate analysis, precut sphincterotomy (P = 0.002, 95%CI: 2.2-27.8, odds ratio = 7.7), biliary balloon sphincter dilation (P = 0.015, 95%CI: 1.4-17.3, odds ratio = 4.9), and trainee endoscopists (P = 0.048, 95%CI: 1.01-8.1, odds ratio = 2.9) were significant risk factors for PEP. CONCLUSION: ERCP for asymptomatic CBD stones should be performed by experienced endoscopists. When performing precut sphincterotomy or biliary balloon sphincter dilation in patients with asymptomatic CBD stones, the placement of a prophylactic pancreatic stent is strongly recommended to prevent PEP.