Side-by-Side Simultaneous Insertion of Covered Metal Stent and Plastic Stent for Malignant Biliary Obstruction: A Pilot Study for Efficacy, Patency and Safety.

Background/Aims Covered metal stent (CMS) for biliary obstruction is expected to have longer patency and lower in growth rate compared to uncovered metal stent (UCMS). However, high migration rate is major concern of CMS. This study aimed to assess clinical outcomes of simultaneous side-by-side insertion of both CMS and PS. Methods CMS with PS was applied into 41 patients from 2017 and patients' medical records were reviewed retrospectively. Technical success was defined as successful placement of stents across a stricture. Functional success was defined as over 50% improvement or normalization in bilirubin within 2 weeks. Results The technical and functional success rate both were 100%. 23 patients (56%) underwent both stents insertion as an initial treatment. Endoscopic sphincterotomy was initially performed for 24 (59%) patients. Median time to recurrent biliary obstruction was 366 days (95% CI 241-490). Six patients (15%) were confirmed as re-stenosis. These all were caused by tumor ingrowth (n=6) and no patients experienced stent migration nor clogging. All patients confirmed as re-stenosis took revision ERCP successfully. Seven patients (17%) died and no procedure-related death was found. Median follow-up was 144 days (15 to 459 days) and median overall survival was not reached due to insufficient follow- up period. Five procedure-related complications were observed, three for liver abscesses, one for acute cholecystitis and one for post-EST bleeding. Liver abscesses occurred at 12, 32 and 70 days after stent placement, respectively. The initial stenosis sites of three liver abscess patients above were confirmed equally as proximal (n=1), hilar (n=1) and distal (n=1) obstruction. No acute cholangitis nor post-ERCP pancreatitis was observed. Conclusions Side-by-side insertion of both CMS and PS showed good success rate, long patency and few stent-related complications. Most notably, no stent migration was observed. This result may provide clinical background for further comparative study with UCMS. [ABSTRACT FROM AUTHOR]