Comparative Outcomes of Treated Sterile vsInfected Walled off Pancreatic Necrosis at a High-Volume Center

Abstract

Introduction: Walled-off necrosis (WON) as sequelae of severe acute, necrotizing pancreatitis has been associated with high morbidity and mortality. Both sterile WON and infected WON can lead to multiorgan failure, with generally held opinions suggesting worse outcomes in infected WON. There is a dearth of studies specifically comparing outcomes between infected WON and sterile WON. Methods: All patients undergoing minimally invasive treatment for symptomatic or infected WON have been maintained in a prospectively collected institutional database since October 2007. We performed a retrospective analysis of this database including patients encountered between October 2007 and June 2015. Infected WON was strictly defined by either positive culture of fluid from the necrotic cavity or sepsis associated with positive blood culture. Patients were treated with either standard percutaneous drainage (SPD) or dual modality endoscopic and percutaneous drainage (DMD). Descriptive statistics were performed for infected and sterile groups, and appropriate univariate analyses were performed to compare the two groups. Results: Overall, 219 patients were included in the analysis. Of these, 111 (50.7%) were classified as infected WON and 108 (49.3%) were sterile WON. When compared to patients with sterile WON, those with infected WON tended to be older (mean age 57.2 vs 51.8; p=0.01). Sex, BMI, and etiologies of pancreatitis were similar in both groups. There were no significant differences in the number of imaging studies nor procedures performed in the two groups. There was no difference between the two groups with regards to type of intervention received (SPD vs DMD). However, the infected WON group had an overall longer length of stay (32 days vs 24 days; p=0.045), were more likely to require ICU-level care (60.3% vs 45.3%; p=0.01), and more likely to require multiple drains (37.8% vs 22.2%; p=0.01) when compared with the sterile WON group. The infected WON group was more likely to have fistulized to surrounding organs (OR 3.6; 95%CI 1.7-7.8; p < 0.001). Six patients in the infected group died during the course of therapy vs 1 patient in the sterile group (p=0.12). Conclusion: When comparing outcomes in patients with infected WON to those with sterile WON, patients with infected WON have a longer length of hospital stay, require ICU management more frequently, require multiple drains, and have more fistulas. Although not statistically significant, infected WON has a numerically higher mortality.