Non-superiority of lumen-apposing metal stents over plastic stents for drainage of walled-off necrosis in a randomised trial

Abstract

Objective: Although lumen-apposing metal stents (LAMS) are increasingly used for drainage of walled-off necrosis (WON), their advantage over plastic stents is unclear. We compared efficacy of LAMS and plastic stents for WON drainage.

Design: Patients with WON were randomised to endoscopic ultrasound-guided drainage using LAMS or plastic stents. Primary outcome was comparing total number of procedures to achieve treatment success defined as symptom relief in conjunction with WON resolution on CT at 6 months. Secondary outcomes were treatment success, procedure duration, clinical/stent-related adverse events, readmissions, length of hospital stay (LOS) and costs.

Results: 60 patients underwent LAMS (n=31) or plastic stent (n=29) placement. There was no significant difference in total number of procedures performed (median 2 (range 2-7) LAMS vs 3 (range 2-7) plastic, p=0.192), treatment success, clinical adverse events, readmissions, LOS and overall treatment costs between cohorts. Although procedure duration was shorter (15 vs 40 min, p<0.001), stent-related adverse events (32.3% vs 6.9%, p=0.01) and procedure costs (US$12 155 vs US$6609, p<0.001) were higher with LAMS. Significant stent-related adverse events were observed ≥3 weeks postintervention in LAMS cohort. Interim audit resulted in protocol amendment where CT scan was obtained at 3 weeks postintervention followed by LAMS removal if WON had resolved. After protocol amendment, there was no significant difference in adverse events between cohorts.

Conclusion: Except for procedure duration, there was no significant difference in treatment outcomes between LAMS and plastic stents. To minimise adverse events with LAMS, patients should undergo follow-up imaging and stent removal at 3 weeks if WON has resolved.

Trial registration number: NCT02685865.

Keywords: endoscopic ultrasonography; pancreatic disease.

Figure 1

Consort flow diagram of patient enrolment. EUS, endoscopic ultrasound; WON, walled-off necrosis.

Figure 2

The lumen-apposing metal stents (LAMS) has completely migrated into the walled-off necrosis (WON) cavity and cannot be visualised on endoscopy (A). Endoscopic image of LAMS almost migrating inside the WON cavity (B).

Figure 3

Endoscopic ultrasound (EUS) image of interlacing vessels within the distal flange of the lumen-apposing metal stents (LAMS) (A). Endoscopic image of LAMS, which was placed 5 weeks previously in the duodenal bulb (B). The LAMS can be seen causing biliary stricture on EUS due to external compression on the common bile duct (C).

Figure 4

Lumen-apposing metal stents (LAMS) was placed via the transgastric route to drain the walled-off necrosis (A). The patient presented 16 days postprocedure with abdominal pain, where a CT showed that the LAMS had migrated out of the transmural tract and into the pylorus resulting in gastric outlet obstruction (B). The LAMS could no longer be seen in the gastric lumen on endoscopy as it had migrated further distally into the jejunum (C). Repeat CT showed that the LAMS had now migrated into the descending colon (D) and finally into the rectosigmoid junction (E), where it was removed via flexible sigmoidoscopy.