Prevention And Preliminary Mechanism Investi-gation For Post-ERCP Cholangitis And Stone Recurrence In Patients With Choledocholithiasis

Objective:This thesis included three studies to provide clinical evidence and theoretical reference for prevention of post-endoscopic retrograde cholangiopancreatography(ERCP)cholangitis(PEC)and stone recurrence in patients with choledocholithiasis.The first study was to analyze the risk factors of PEC and stone recurrence in patients with choledocholithiasis.The second study was to determine whether PEC can be prevented in patients with choledocholithiasis undergoing complete stone removal if a self-developed biliary spontaneous dislodgement spiral stent(BSDSS)was inserted.The third study was to investigate the changes of duodenal and biliary microbiota,and its role in stone recurrence.Methods:1.The first study was a single-center,retrospective study,which consecutively enrolled in patients with choledocholithiasis undergoing ERCP from January 1,2010 to December 31,2015 at Endoscopy Center of West China Hospital,Sichuan University.The primary outcomes were the incidences of PEC and stone recurrence,as well as their independent risk factors.Multivariate logistic regression analysis was used to determine the independent risk factors of PEC and stone recurrence.2.The second study was a single-center,prospective,randomized controlled study,which consecutively enrolled in patients with choledocholithiasis undergoing ERCP from August 1,2018 to July 23,2020 at Endoscopy Center of West China Hospital,Sichuan University.Eligible patients were randomly assigned to BSDSS group(inserting a BSDSS after complete stone removal for short-term biliary drainage)and control group(pulling back the endoscope directly after complete stone removal).General characteristics,intraoperative parameters,postoperative and follow-up outcomes were collected and compared between the two groups.The primary outcome was the incidence of PEC.Secondary outcomes included post-ERCP pancreatitis(PEP),bleeding,perforation,and BSDSS related complications.Other outcomes included postoperative hospital stay,medical costs,and the duration to BSDSS dislodgement.3.The third study was a single-center,prospective,cross-sectional study,which enrolled in patients with choledocholithiasis undergoing ERCP from June 24,2019 to October 27,2020 at Endoscopy Center of West China Hospital,Sichuan University.Eligible patients were divided into recurrent group(stone recurrence after 6 months of complete stone removal)and primary group(choledocholithiasis without previous ERCP).General characteristics,duodenal fluid,and bile were collected.16S rRNA third-generation sequencing was used to describe duodenal and biliary microbiota,and their differences between the two groups.Liquid chromatography mass spectrometry was used to measure the bile acids.Spearman correlation analysis was used to determine the correlation between microbiological marker,stone recurrence,and the bile acids.Vitro testing was also applied to confirm the role of the marker in bile acids metabolism.Results:1.This first study included 883 patients with choledocholithiasis undergoing ERCP for analysis of PEC.The incidence of PEC was 3.62%(32/883).Asymptomatic choledocholithiasis patients(odds ratio[OR]=4.581,95%confidence interval[CI]=1.239-16.935,P=0.023),and the dislocation of nasobiliary tube(OR=8.165,95%CI=2.094-31.838,P=0.002)were independent risk factors for PEC.This first study also included 475 patients with choledocholithiasis undergoing ERCP for analysis of stone recurrence.The incidence of stone recurrence was 8.63%(41/475).Combined history of choledocholithotomy(OR=2.904,95%CI=1.2047.006,P=0.018)was the independent risk factor for stone recurrence,while small incision(OR=0.098,95%CI=0.028-0.339,P<0.001)and median incision(OR=0.297,95%CI=0.109-0.808,P=0.017)were protective factors for stone recurrence.2.This second study included 166 patients with choledocholithiasis undergoing ERCP for random assignment,with 83 patients in the BSDSS group and 83 patients in the control group.All patients underwent small incision,median incision,and/or small papillary balloon dilation(≤10mm)for stone removal.The general characteristics and intraoperative parameter were similar in the two groups.The incidence of PEC in the BSDSS group was significantly lower than that in the control group(0%vs.8.43%,P=0.014).The incidence of PEP was also significantly lower in the BSDSS group than in the control group(4.82%vs.14.46%,P=0.035).There were no differences in the incidence of bleeding and perforation in the two groups.There were no BSDSS related complications in the BSDSS group.Postoperative hospital stay and medical costs were similar between the BSDSS group and the control group.The median duration to BSDSS dislodgement was 4(interquartile range:2)days.3.The third study included 50 patients with choledocholithiasis undergoing ERCP,with 17 patients in the recurrent group and 33 patients in the primary group.Enterococcus could be used as a microbiological marker of the duodenal microbiota to distinguish the recurrent group from the primary group,and Enterococcus faecium could be used as a microbiological marker of the biliary microbiota to distinguish the recurrent group from the primary group.The relative abundance of Enterococcus faecium in the bile was strongly correlated with stone recurrence(r=0.63,P<0.001).Stone recurrence was strongly correlated with the ratio of unconjugated bile acids/conjugated bile acids in the bile(r=0.57,P<0.001).The relative abundance of Enterococcus faecium in the bile was also strongly correlated with the ratio of unconjugated bile acids/conjugated bile acids(r=0.55,P<0.001).During vitro testing,and the ratio of unconjugated bile acids/conjugated bile acids was significantly increased(0.098[interquartile range:0.13]vs.0.0005[interquartile range:0.01],P=0.005)when Enterococcus faecium was added into the bile.Conclusion:1.Asymptomatic choledocholithiasis patients,and the dislocation of nasobiliary tube are independent risk factors for PEC in patients with choledocholithiasis.2.Combined history of choledocholithotomy is the independent risk factor for stone recurrence in patients with choledocholithiasis,while small incision and median incision are protective factors for stone recurrence.3.Insertion of a BSDSS in patients with choledocholithiasis undergoing small incision,median incision,and/or small papillary balloon dilation for complete stone removal can significantly reduce PEC and PEP.4.In patients with choledocholithiasis undergoing ERCP,continual discharge of bile into duodenum can change duodenal microbiota;the predominant bacteriaEnterococcus faecium in the duodenum can reflux to bile duct through papillary opening,and thus increase unconjugated bile acids and promote stone recurrence.