BACKGROUND AND AIMSLumen-apposing metal stents (LAMSs) are effective in resolving walled-off necrosis (WON) of the pancreas and enable direct endoscopic necrosectomy (DEN). However, optimal DEN timing is controversial. We aimed to study if early DEN shortens WON resolution time. METHODSWe retrospectively reviewed patients who underwent LAMS placement for WON at a tertiary center. We collected patient demographics, WON characteristics, DEN sessions, and outcomes. We compared those who underwent immediate DEN (iDEN; index DEN at LAMS placement) and delayed DEN (dDEN; index DEN on a separate day from LAMS placement). We identified predictors for resolution time via linear regression, and constructed Nelson-Aalen cumulative hazards curves showing resolution time stratified by index DEN timing. RESULTSBetween January 2011 and June 2019, 175 patients underwent LAMS placement for peripancreatic fluid collections, 155 (88.6%) of which were WON. Of these, 50 (32.3%) required DEN. The majority were male (80%) with an average age of 52.5 years. WON size and double-pigtail stent use through LAMS were similar. Overall, the mean time to WON resolution was 90.6 days, 44.5 (iDEN) versus 100.7 (dDEN), P = 0.02, with similar DEN sessions (P = 0.64). The average length of stay was 0.9 in iDEN versus 14.7 days in dDEN (P = 0.03). All had WON resolution with a similar adverse event rate (18.5% iDEN vs 25.1% dDEN, P = 0.45). In multivariate analysis, double-pigtail stent use suggested greater complexity and longer WON resolution time (P = 0.005). CONCLUSIONDespite similar DEN sessions, LAMS with iDEN significantly reduced resolution time compared with dDEN. Only one-third of WON patients treated with LAMS placement required DEN.