The Effect Of Cannulation Time On Post-ERCP Pancreatitis In Patients Undergoing ERCP

?Background? Endoscopic retrograde cholangiopancreatography(ERCP)is currently one of the most important methods for the diagnosis and treatment of biliary and pancreatic diseases.With the development for nearly half of a century,ERCP has now become a mature and safe technique.However,the complications of ERCP remain inevitable because of various reasons,which hamper the more widely application of ERCP.ERCP complications also cause undesirable consequences to a minority of patients with biliary and pancreatic diseases.The main complications of ERCP include post-ERCP pancreatitis(PEP),bleeding,perforation and biliary infection.The most common complication of ERCP is PEP with the incidence of 3.8% to 13.3%.In the past 30 years,PEP is a hot area for the clinical research of ERCP.Based on the identification of high risk factors,the two key points for the management of PEP are the standardization of ERCP performance and the active prophylaxis.Several risk factors have been identified in the recent years,including female,prior history of PEP and pancreatitis,suspected sphincter of Oddi dysfunction(SOD),precut,difficult cannulation,inadvertent pancreatic duct(PD)cannulation and PD contrastopacification.The other possible risk factors include age,normal bilirubin and normal diameter of common bile duct(CBD),which need to be further investigated in the future.Cannulation time is a potential factor which may affect the occurrence of PEP.With the long procedure of cannulation,the cannulation attempts,inadvertent cannulation of PD,the trauma on papilla and the use of advanced cannulation techniques will be increased.Thus,longer cannulation time may be accompanied with higher PEP.It is necessary to precisely record the cannulation time by an additional assistant in the studies investigating the relationships between cannulation time and PEP.However,the data of cannulation time are lack in most of studies associated with PEP.In the few studies containing the data of cannulation time,the sample size is relatively small.There are only few studies evaluating the relationships between cannulation time and post-ERCP complications.?Objective? To optimize the cannulation method and the management of post-ERCP complications,the current study analyzed the correlation among patient-related parameter,cannulation-related parameters and ERCP complications.The main purposes of this study included:(1)to screen the high risk factors associated with PEP and investigate the relationships between cannulation time and PEP;(2)to evaluate the relationships between cannulation time and other complications;(3)to identify the risk factors causing prolonged cannulation time.?Methods? The data of cannulation time was prospectively collected between 2010 to 2012 in ERCP patients with native papilla in our hospital.The following data were retrospectively collected,including demographic data of patients,comorbidities,indications,parameters related to ERCP performance and complications.The primary outcome was PEP.It was diagnosed if there was worsen or new onset of upper abdominal pain associated with an elevated serum amylase of at least three times the upper limit of normal range at 24 h after the procedure,and admission to hospital for at least 2-3 nights.The severity of PEP and other complications were defined according to the Cotton's criteria.Logistic regression analysis was used to assess the effect of single variable on PEP.To adjust confoundingfactors,multivariate analysis was used for those covariates with p values of <0.1 in single factor analysis.The effects of different cannulation time on PEP and other complications were analyzed.Log-rank test was used to assess the effect of single variable on cannulation time.To adjust confounding factors,multivariate analysis(Cox regression analysis)was used for those covariates with p values of <0.1 in single factor analysis.All reported p-values were results of two-side test and those <0.05 was considered to be significant.?Results? There were 1625 ERCP patients meeting the inclusion and exclusion criteria,including 815 male and 810 female.The mean age of these patients were 59.The main findings were shown as following:(1)42.8% patients had the prior history of cholecystectomy and 2.6% were accompanied with duodenal stenosis.The indications of ERCP included CBD stones(60.9%),benign biliary stricture(2.7%),malignant biliary stricture(20.2%),suspected SOD(6.8%)and chronic pancreatitis(3.8%)etc.(2)CBD was targeted in 97% of patients during selective cannulation.About 30% of patients had biliary stricture.The diverticulum was found in about 15% of patients.The overall success rate of cannulation was 97.8%.The median cannulation time for success was 5.87min(95%CI[5.30-6.42]).The overall complication rate was 9.7%.The incidence of PEP was 4.6%.(3)The logistic multivariate regression analysis revealed that precut(P=0.02;OR 1.93 95%Cl[1.10-3.39]),cannulation time ?8 min(P<0.01;OR 3.50 95%Cl[2.00-6.13]),duodenal stricture(P=0.03;OR 2.92 95%Cl[1.08-7.86])were independent risk factors associated with PEP.The incidence of PEP was increased with the prolongation of cannulation time within 30 min.(4)Similarly,cannulation time was also found to be a risk factor for overall complications.The incidence of post-ERCP complications were increased with the prolongation of cannulation time within 30 min.The cannulation time has significant impact on biliary infection.If the cannulation time was ?18 min,the incidence of post-ERCP biliaryinfection was significantly increased.(5)The length of cannulation time was affected by several factors.It was revealed by COX multivariate regression analysis that prior failure of ERCP(P=0.028;HR0.67 95%CI[0.46~0.96]),suspected SOD(P=0.001;HR 0.72 95%CI[0.59~0.87]),malignant biliary stricture(P<0.001;HR 0.74 95%CI[0.64~0.85])and precut(P<0.001;HR 0.36 95%CI[0.31~0.42])were independent risk factors for prolonged cannulation time.?Conclusion? To the best of our knowledge,it was the largest retrospective cohort study which contained the data of cannulation time.The prolonged cannulation time was related to several complications.It was also the independent risk factor for PEP.The overall PEP was increased significantly if cannulation time was ?8min.It may need special concern regarding the strategy of cannulation and prophylaxis of complications.The cannulation time was prolonged in patients with prior history of ERCP failure,malignant biliary stricture and suspected SOD etc.Taken together,this study indicated that it be necessary to record cannulation time during ERCP,which might improve the performance quality of ERCP and lead to better prevention and management of post-ERCP complications.