Pancreatitis remains the most common complication of ERCP, with the reported incidence ranging from 2% to 9%. Although 80% of cases are mild, a significant number of patients may develop severe pancreatitis, that means additional morbidity and risk for death. ERCP, despite the development of new diagnostic tools, remains a widely used procedure, so post-ERCP pancreatitis is a problem with significant impact. Several studies and meta-analyses helped us to recognize special factors that put an individual in high risk for the development of post-ERCP pancreatitis. Among these factors special interest presents the history of post-ERCP pancreatitis as an independent risk factor for a new episode of post-ERCP pancreatitis. It seems that some individuals have a genetically predisposed susceptibility in this particular complication. The aim of the present study is to investigate the possible genetic variation associated with post-ERCP pancreatitis using whole genome sequencing.

This study includes patients who are at high risk of post-ERCP pancreatitis. Blood samples will be gathered to investigate the possible genetic variation associated with post-ERCP pancreatitis using whole genome sequencing. DNA for whole genome sequencing will be extracted using DNA extraction kit (Qiagen Inc., Hinden, Germany) and the concentration & purity of DNA will be measured using Nanodrop (Nano Drop Technologies, Wilmington, DE, USA) or fluorometric quantitation(Qubit fluorometer). Genetic variations which are associated with acute pancreatitis will be searched using whole genome sequencing. Post-ERCP pancreatitis is the primary outcome. Medical records and data of genetic variations will be reviewed for identifying possible risk factors and genetic variations associated with post-ERCP pancreatitis.

Inclusion Criteria:

• Patients who undergo ERCP with high risk factors of post-ERCP pancreatitis

Exclusion Criteria:

• <18 years old
• current pancreatitis (<72hrs before ERCP)
• pregnant woman, breast-feeding woman
• patient refusal
• contraindication of ERCP
• patients who would only be treated of bile duct such as a change of stent with previous endoscopic sphincterotomy
• chronic pancreatitis
• patients who underwent gastrectomy (Billroth II or Roux-en Y anastomosis)
• patients who have pancreatic or distal bile duct cancer

Patients who are at high risk of post-ERCP pancreatitis, who have at least one of the following factors: clinically suspected sphincter of Oddi dysfunction, history of post-ERCP pancreatitis, pancreatic sphincterotomy, precut sphincterotomy, difficult cannulation, balloon dilatation of intact sphincter, endoscopic ampullectomy, and 2≥minor criteria(an age of less than 50 years and female sex, a history of recurrent pancreatitis (≥2 episodes), three or more injections of contrast agent into the pancreatic duct with at least one injection to the tail of the pancreas, excessive injection of contrast agent into the pancreatic duct resulting in opacification of pancreatic acini,the acquisition of a cytologic specimen from the pancreatic duct with the use of a brush).