Encapsulation levels rather than elapsed time after the onset of acute pancreatitis are related to clinical outcomes of pancreatic walled-off necrosis

BACKGROUND: There is no consensus regarding the optimal timing of endoscopic ultrasound (EUS)-guided interventions for walled-off necrosis (WON) secondary to acute pancreatitis. Currently, the intervention timing is primarily determined by the duration after the onset of acute pancreatitis, which potentially serves as a surrogate for fluid collection maturation. We hypothesized that the encapsulation status may be more strongly correlated with clinical outcomes. METHODS: Between January 2010 and November 2020, 222 patients who underwent EUS-guided WON treatment at 11 centers of the WONDERFUL consortium were included. The patients were divided into two groups based on their encapsulation status at drainage (partial/no vs. complete). The clinical outcomes were compared between groups. RESULTS: Technical success rates were similar between the groups. Complete encapsulation was associated with a higher clinical success rate (88.0% vs. 52.1%, P < 0.01). When patients were classified by both time elapse and encapsulation status, the encapsulation status was more strongly associated with clinical success. The encapsulation status was associated with a lower overall adverse event rate (22.7% vs. 39.1%, P = 0.03). The overall mortality was significantly higher in the partial/no encapsulation group (34.7% vs. 3.4%, P < 0.01). In multivariable analysis, the encapsulation status and diameter of the WON were identified as significant factors associated with clinical success. CONCLUSIONS: In patients undergoing EUS-guided WON treatment, the encapsulation status, rather than the time elapsed since disease onset, appeared to be associated with clinical outcomes.