This study compares the effect of endoscopic sphincterotomy and endoscopic papillary balloon dilation in the treatment of acute biliary pancreatitis.Participants with acute biliary pancreatitis will be randomized into either the endoscopic sphincterotomy or endoscopic papillary balloon dilation groups.Moreover, the investigators compare the results obtained from the traditional bile/blood culture and metagenomics.

Early endoscopic retrograde choledocho pancreatogram with endoscopic sphincterotomy is suggested in patients with acute biliary pancreatitis to reduce complication and mortality. Retrospective study of the investigators' hospital showed that endoscopic papillary balloon dilation is safe in the treatment of acute biliary pancreatitis. However, there is no report in literature concerning about the prospective study comparing the effect of endoscopic sphincterotomy and endoscopic papillary balloon dilation in the treatment of acute biliary pancreatitis.

Moreover, the presence of infective microorganisms in the biliary and/or pancreatic ducts may play important role in both the onset and outcome of acute biliary pancreatitis. Blood or bile obtained via endoscopic means is another way to know the causative bacterium/bacteria.

However, it still need considerable period of time to get the result of the culture. Recently, next-generation sequencing technologies have been developed, which can facilitate the analysis of a large number of microorganisms in different environments and human body sites. 16S(a svedberg unit) ribosomal deoxyribonucleic acid sequence analysis and metagenomics are two effective DNA sequencing approaches, and both have been used to study uncultivated gut microbial communities.

Aims:

1. To study the clinical effects of endoscopic sphincterotomy and endoscopic papillary balloon dilation in acute biliary pancreatitis.
2. To compare the results obtained from the traditional bile/blood culture and metagenomics.

Methods: Beginning from Jan 2016, patients with age ≥ 20 years and acute biliary pancreatitis concomitant with either signs of acute cholangitis or bile duct obstruction will be enrolled in the study. Participants will be randomized into either the endoscopic sphincterotomy or endoscopic papillary balloon dilation groups. The treatment effects and safety of both groups will be compared. The primary endpoint is the relative successful rates of retrieval of common bile duct stones of both groups. The secondary endpoint is the frequency of use of mechanical lithotripter, other drainage procedures, complication and mortality, as well as the number of treatment sections.

Besides blood culture exam, bile will be aspirated by placing a single-use, 5-French, standard catheter (after guide-wire cannulation) into the bile duct before the injection of contrast agent for endoscopic retrograde cholangiopancreaticography. Approximately 10 mL of bile will be collected and transferred in a sterile tube. Half of the bile obtained will be transported to the microbiology laboratory in blood culture bottles and in an anaerobic transport system. Bacteria will be cultured and identified according to the standard protocol used in our clinical microbiology laboratory. Another half of the bile specimen will be sending for metagenomic study. Finally, investigators will try to compare the results obtained from the traditional bile culture /blood culture and metagenomics, and to understand the effects of infective microorganisms in the biliary and/or pancreatic ducts on the acute biliary pancreatitis. In addition, investigators want to find out the best means of early and accurate diagnosis of the pathogen responsible for the infection.

Patients with age ≥ 20 years and acute biliary pancreatitis concomitant with either signs of acute cholangitis or bile duct obstruction will be enrolled in the study. They will be randomized into two treatment groups (sphincterotomy vs. balloon dilation).

Inclusion Criteria:

Patients diagnosed with acute gallstone pancreatitis and fulfill any two items from a to c, plus one item in d, and e:

1. abdominal pain typical of pancreatitis;
2. elevation of serum amylase and/or lipase up to three times above normal;
3. imaging studies (abdominal ultrasound or abdominal computed tomography) showed evidence of pancreatitis
4. common bile duct stones, acute cholangitis (Charcot's triad), total bilirubin (total bilirubin)> 4mg / dL, bile duct dilatation (diameter> 6mm with intact gallbladder, or> 10mm when the gallbladder has been removed) plus total bilirubin 1.8 ~ 4mg / dL;
5. exclude other causes of acute pancreatitis.

Exclusion Criteria:

• septic shock
• serious coagulopathy (international normalized ratio 1.5, partial thromboplastin time greater than twice that of control, platelet count <50 x 1000 / Cumm)
• malignant tumors of the biliary and pancreatic tract
• severe cardiovascular or mental illness which can not cooperate with the exam and treatment;
• pregnant women
• patient who had ever received surgery or endoscopic treatment for biliopancreatic tract