Risk Factors for Post-ERCP Pancreatitis in High Risk Patients Who Have Undergone Prophylactic Pancreatic Duct Stenting: A Multicenter Retrospective Study

Background and Aim Pancreatitis remains a serious complication after endoscopic retrograde cholangiopancreatography (ERCP). The efficacy of prophylactic pancreatic duct stent placement to prevent post-ERCP pancreatitis in patients at high risk has been established in several randomized controlled trials. The aim of this study was to investigate the frequency and risk factors of post-ERCP pancreatitis in patients who had undergone prophylactic pancreatic duct stenting. Patients and Methods Between July 2002 and January 2010, ERCP-related procedures were performed in 9192 cases of pancreatobiliary diseases at seven institutions. Among them, 414 patients (246 men, 168 women; mean age, 68 yr; age range, 22-91 yr) at high risk of post-ERCP pancreatitis who had undergone prophylactic pancreatic duct stenting were included in this study. The stent used in the present study was a 5-Fr stent with a single duodenal pigtail, which is made of soft polyethylene and has no flange (Pit-stent: Cathex, Co., Ltd., Tokyo, Japan). The pancreatic duct stent was placed via the channel of the duodenoscope over a guidewire with the assistance of fluoroscopy at the end of the procedure. The frequency and risk factors of post-ERCP pancreatitis were investigated. Post-ERCP pancreatitis was defined based on the consensus criteria. Results Therapeutic ERCP was performed in 52% of the patients. Indications for prophylactic pancreatic duct stenting were as follows: difficult cannulation of the bile duct, 192; pancreatic duct cytology/biopsy, 95; precut sphincterotomy, 40; pancreatic sphincterotomy, 29; female gender, 28; papillectomy, 25; sphincter of Oddi dysfunction, 12; history of pancreatitis, 10. Hyperamylasemia at 18-24 h after ERCP was observed in 64% (267 patients) of the patients. Pancreatitis occurred in 9.9% (41 patients: mild, 37; moderate, 2; severe, 2). Univariate analysis revealed intraductal papillary mucinous neoplasm (IPMN) of the pancreas to be the only significant risk factor for pancreatitis (OR 2.9, 95% CI 1.2, 7.1). Multivariate analysis also showed IPMN to be the only risk factor for pancreatitis (OR 3.1, 95% CI 1.2, 7.8). The mean diameter of the pancreatic head duct in patients with IPMN who developed post-ERCP pancreatitis was significantly smaller than that in those who did not develop pancreatitis (3.0 +/- 1 mm vs 4.7 +/- 2.6 mm, p=0.0037). Conclusion Post-ERCP pancreatitis developed in 9.9% of the patients at high risk who had undergone prophylactic pancreatic duct stenting. Since the majority of cases of post-ERCP pancreatitis were mild, pancreatic duct stenting may contribute to lessening the severity of pancreatitis. The present results suggest that IPMN without a dilated pancreatic head duct is a possible risk factor for post-ERCP pancreatitis after prophylactic pancreatic duct stenting.