Evolution of Transluminal Necrosectomy for Acute Pancreatitis to Stent in Stent Therapy: Step-Up Approach Leads to Low Mortality and Morbidity Rates in 302 Consecutive Cases of Acute Pancreatitis.

Background: The step-up approach, using either flexible endoscopy or a minimal invasive retroperitoneal access, has reduced mortality and morbidity in patients with acute pancreatitis. The use of fully covered self-expanding metal stents (FCSEMS) or lumen apposing metal stents (LAMS) facilitates endoscopic necrosectomy and drainage of walled-off necrosis (WON). The aim of our analysis was to investigate the 30/90/365-day mortality and morbidity rates of the subtypes of the revised Atlanta classification for acute pancreatitis. Materials and Methods: We conducted a retrospective analysis of all patients ( n  = 302) treated with acute pancreatitis in our institution from January 2014 to July 2017. Mortality, morbidity, management of fluid collections, interventions, complications, and new onset of diabetes were recorded. Results: In 30.8% ( n  = 93/302) of patients, pancreatic fluid collection developed. Out of these, 58.1% (54/93) required intervention, consisting of endoscopic treatment in 63% (34/54) or multidisciplinary approach in 37% (20/54). Overall, 90-day mortality rate according to Kaplan-Meier Estimator was 3.7%. Overall, 1-year mortality rate was 6.2%. One-year mortality for uncomplicated acute pancreatic fluid collection, pseudocyst, and WON were 5.4%, 2.6%, and 13.5%, respectively. Hemorrhage in case of metal stent treatment (FCSEMS/LAMS) occurred in 14.3%. If LAMS was combined with double pigtail stent-in-stent, bleeding was seen in 5.3%. No transperitoneal necrosectomy was needed. Conclusions: Treating acute pancreatitis with a step-up approach, including stent-in-stent procedures, leads to low mortality rates and few stent-associated bleeding complications and minimizes necessity for open transperitoneal surgical necrosectomy.