Pancreatitis is the most common and serious complication following post-endoscopic retrograde cholangiopancreatography (ERCP) and is associated with occasional mortality, extended hospital stays, and increased healthcare expenses. Rectal non-steroidal anti-inflammatory drugs (NSAIDs) and pancreatic duct stent (PDS) placement were demonstrated to be effective strategyies to reduce PEP incidences, particlularly in high-risk patients for post-ERCP pancreatitis (PEP).

Rectal NSAIDs were easy-to-use and safe, while PDS placement were technically complex and carried higher risks of adverse events. A previous network meta-analysis suggested rectal NSAIDs in combination with PDS placement did not differ from rectal NSAIDs alone in PEP prevention. To invesigate if rectal NSAIDs alone could obivate the need of PDS placement, a recent trial from Elmunzer et al. conducted a randomized trial to investigate if rectal NSAIDs alone was non-inferior to the combination of NSAIDs with PDS in high-risk patients. The trial found that the PEP incidence rate in combination group was significantly lower than that in NSAIDs alone group. However, post-hoc analysis of the study suggested that the combination strategy conferred significant benefits only in high-risk patients with pancreatic duct (PD) wire passage, but not in those with other risk factors. Therefore, we hypothesized that rectal NSAIDs alone may obivate the need of PDS in high-risk patients without PD wire passages. Here, we conducted a multicenter, randomized and non-inferiority trial to investigate whether rectal NSAIDs alone is non-inferior to NSAIDs plus PDS placement in high-risk patients without PD wire passages.

Inclusion Criteria:

• 18-90 years old patients with native papilla who planned to undergo ERCP
• high-risk patients for post-ERCP pancreatitis must meet one or more following criteria: clinical suspicion of sphincter of Oddi dysfunction, a history of PEP, pancreatic sphincterotomy, precut sphincterotomy, difficult cannulation (>5 cannulation attempts, or >5mins cannulation time, or >1 unintentional pancreatic duct cannulation), or ballon dilatation of an intact biliary sphincter ≤ 1 min, double-wire cannulation. Additionally, patients were considered high-risk if they fulfilled two or more of the following minor criteria: female gender under 50 years old, a history of recurrent pancreatitis (two or more episodes), three or more contrast injections into the pancreatic duct with at least one injection reaching the tail of the pancreas, opacification of pancreatic acini, or brush cytology performed on the pancreatic duct.

Exclusion Criteria:

• Previous biliary sphincterotomy and papillary large balloon dilation
• Planned for placements of pancreatic duct stents (eg. pancreatic duct strictures, planned ampullectomy)
• Allergy to NSAIDs
• The administration of NSAIDs within 7 days
• Not suitable for NSAIDs administration (gastrointestinal hemorrhage within 4 weeks, renal dysfunction [Cr >1.4mg/dl=120umol/l]; presence of coagulopathy before the procedure)
• Acute pancreatitis within 7 days before ERCP or acute pancreatitis with obvious Pancreatic edema and peripancreatic fluid collections
• Hemodynamical instability
• Pregnancy or lactation
• high-risk patients with pancreatic duct wire passages