Brushing the Distal Biliary Stricture in the Surrounding of the Papilla Increased the Risk of Post-Endoscopic Retrograde Cholangiopancreatography Pancreatitis: A Retrospective Study Using Propensity Score Analysis

Background and aims: Brushing cytology is useful for diagnosing biliary strictures. With regard to biliary stricture brushing at the distal common bile duct in the surrounding of the papilla, the risk of post-endoscopic retrograde cholangiopancreatography pancreatitis is unknown. Our study aimed to evaluate the risk of post-endoscopic retrograde cholangiopancreatography pancreatitis by using this procedure. Methods: A total of 150 endoscopic retrograde cholangiopancreatography-naive patients undergoing endoscopic retrograde cholangiopancreatography including biliary stricture brushing were retrospectively analyzed. Patients were divided into two groups: the surrounding of the papilla group (n=25) and the other group (n=125). The primary outcome was the post-endoscopic retrograde cholangiopancreatography pancreatitis incidence. We analyzed the risk of post-endoscopic retrograde cholangiopancreatography pancreatitis by using inverse probability of treatment weighting based on propensity scores to adjust for selection bias. Results: The overall incidence of post-endoscopic retrograde cholangiopancreatography pancreatitis was 11.3%, and post-endoscopic retrograde cholangiopancreatography pancreatitis of the surrounding of the papilla group occurred significantly more frequently than in the other group (32.0% vs 7.2%, p<0.01). Multivariate analysis showed that this procedure was a risk factor for post-endoscopic retrograde cholangiopancreatography pancreatitis (odds ratio, 10.6; 95% confidence interval, 2.82-40.2; p<0.01). In the propensity-weighted model, this procedure was an independent risk factor for post-endoscopic retrograde cholangiopancreatography pancreatitis (odds ratio, 8.42; 95% confidence interval, 2.12-32.4; p<0.01) by multivariate analysis. Conclusions: Biliary stricture brushing at the distal common bile duct in the surrounding of the papilla may increase the risk of post-endoscopic retrograde cholangiopancreatography pancreatitis compared with brushing other portions.