Predictors of the need for necrosectomy in patients with walled-off pancreatic necrosis treated with lumen apposition metal stents

Background and aims Endoscopic necrosectomy through lumen apposition metal stents (LAMS) is increasingly being used for complicated walled-off pancreatic necrosis (WOPN), but the need for necrosectomy after stent placement is not well understood. The aim of this study was to evaluate clinical, endoscopic, and radiologic predictors of the need for necrosectomy in patients treated with LAMS. Methods We retrospectively reviewed patients with WOPN treated with LAMS from 2014 to 2017. Necrosectomy was performed only in patients who had recurrent fever or hemodynamic instability during follow-up. Univariate and multivariate analyses were performed. Results We included 15 patients, 67% men and median age was 75 (54-76) years. Two (13%) presented adverse events, one immediate and one delayed. In the first case, the stent migrated to the gastric cavity during deployment but was relocated in the same procedure. In the second case, the patient presented bleeding on day 36 due to a pseudoaneurysm that was successfully treated with embolization. Clinical success was 100%, but five patients (33%) required endoscopic necrosectomy (4 mechanical and 1 irrigation) and one (7%) required surgical necrosectomy of distant collections. The percentage of necrosis in the collection detected in a previous CT scan (45 [35-66]% vs 10 [5-17]%) was the only factor to predict the need for necrosectomy in the multivariate analysis (OR 1.18 [1.01-1.39]). Conclusion LAMS is efficient to treat WOPN but more than a third will need necrosectomy. The percentage of necrosis in the collection detected in the CT scan seems to predict the need for necrosectomy.