A Comparison Of Covered And Uncovered Self-expandable Metal Stents In Efficacy And Safety For The Palliative Treatment Of Malignant Distal Biliary Stricture

ObjectiveTo compare the efficacy and safety of covered self-expandable metal stents(CSEMSs)and uncovered self-expandable metal stents(USEMSs)in palliation of malignant distal biliary stricture.MethodsThe clinical and pathological data of 238 patients with malignant distal biliary stricture in the department of Gastroenterology of the First Affiliated Hospital of Nanchang University from November 2014 to March 2019 were analyzed retrospectively.Diagnostic criteria of malignant biliary stricture included malignant lesions confirmed by pathological examination such as brush cytology,endoscopic tissue biopsy or surgical specimens.For the patients who could not be diagnosed by or refused or were not able to complete the above-mentioned pathological examinations,malignant progression after 1-year follow-up also indicated malignant stricture.The changes of laboratory indicators were compared between CSEMSs group and USEMSs group before and after endoscopic treatment and the efficacy indicated by mean stent patency,stent patency rate,mean patient survival time and survival rate,and safety of CSEMSs and USEMSs placement were analyzed.ResultsA total of 238 patients with SEMS placement under endoscopic retrograde cholangiopancreatography(ERCP)were enrolled: 55 CSEMSs and 183 USEMSs.After stent placement,bilirubin and transaminase level decreased significantly in both CSEMSs group(except for the decrease of total bilirubin level)and USEMSs group(P<0.05).However,the liver functions of the two group were not significantly different both before and after endoscopic treatment.The mean stent patency time was significantly longer in the CSEMSs group than that in the USEMSs group(262.8±195.3 days vs 169.5±155.7 days,P=0.002).Mean patient survival time was significantly longer in the CSEMSs group than in the USEMSs group(273.9±197.6 days vs 184.9±167.6 days,P=0.003).The cumulative stent patency rate and cumulative patient survival rate of the CSEMSs group were higher than those of the USEMSs group(P<0.05).There was no significant difference in the stent patency rate and patient survival rate between the two groups at 1 and 3 months(P >0.05),but they were significantly higher in the CSEMSs group than in the USEMSs group at 6 and 12 months(P<0.05).During the follow-up,there was no significant difference between the two groups in incidence of stent dysfunction(20% vs 18.6%,P=0.813).The cause analysis of stent dysfunction showed that the tumor ingrowth was more common in the CSEMSs group(P=0.042).There was no significant difference in the proportion of sludge formation,stent migration and bleeding between the two groups(P>0.05).There was no significant difference between the two groups in the total incidence of complications(25.5% vs 19.7%,P=0.356).The incidence of post-ERCP pancreatitis was significantly higher in the CSEMSs group than in the USEMSs group(18.1% vs 8.8%,P=0.049).There was no significant difference in the incidence of biliary infection,hyperamylasemia and bleeding between the two groups(P>0.05).There was no procedure-related death in CSEMSs group and USEMSs group has 3 cases of procedure-related death(1 patient died of postoperative bleeding and 2 patients died of acute liver failure or multiple organ failure secondary to biliary infection after endoscopy and drug treatment),but there was no significant difference in procedure-related death between two groups(P=1).ConclusionIn terms of efficacy,after palliative treatment of biliary stent placement in patients with malignant distal biliary stricture,the liver function was improved dramatically in both groups and the short-term(within 1 week)effect of USEMSs group was similar to that of CSEMSs group.The mean stent patency time,cumulative stent patency rate,mean patient survival time and cumulative patient survival rate in the CSEMSs group were better than those in the USEMSs group.The stent patency rate and patient survival rate were not significantly different between the two groups at 1 and 3 months,but they were significantly higher in the CSEMSs group than in the USEMSs group at 6 and 12 months,which indicated that the long-term efficacy of CSEMSs is significantly better than of USEMSs.In terms of safety,the incidence of post-ERCP pancreatitis was higher in the CSEMSs group than that in the USEMSs group.There was no significant difference in the incidence of other postoperative complications(such as biliary infection,hyperamylasemia and bleeding)and procedure-related mortality between the two groups.