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

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/stentrelated 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.