"Innocent as a LAMS": Does Spontaneous Fistula Closure (Secondary Intention), After EUS-Directed Transgastric ERCP (EDGE) via 20-mm Lumen-Apposing Metal Stent, Confer an Increased Risk of Persistent Fistula and Unintentional Weight Gain?

Background And Aims: Persistent gastrogastric or jejunogastric fistula is theoretically a concerning sequela of EUS-directed transgastric ERCP/EUS (EDGE), as it may functionally reverse the malabsorptive mechanism of Roux-en-Y gastric bypass (RYGB). Prior EDGE studies, using predominantly 15-mm (diameter) lumen-apposing metal stents (LAMS) and fistula closure by primary intent, collectively report 9% persistent fistula rate, without a clear weight gain association. Our study determines the incidence of persistent fistula, and its association with unintentional weight gain, among recipients of EDGE via 20-mm LAMS followed by spontaneous fistula closure (secondary intent).

Methods: We conducted a dual-center prospective cohort study of 22 RYGB patients who underwent EDGE using 20-mm between 3/2018 and 10/2019. After LAMS extraction, all GGFs/JGFs were allowed to heal spontaneously. Objective testing for persistent fistula and total body weight (TBW) occurred a minimum of 8 weeks after LAMS extraction.

Results: Persistent fistula was identified in 9 patients (41%). Longer LAMS dwell time (median 77-days) was observed in the persistent fistula group, compared to those with durable spontaneous fistula closure (median 35-days) (p = 0.03). Weight gain of ≥ 5% TBW occurred in 56% (n = 5) of patients with persistent fistula, compared to 15% (n = 2) of patients with spontaneous fistula closure (p = 0.128). Four patients with symptomatic persistent fistulas underwent attempted endoscopic fistula closure a median 7.5 months after LAMS extraction. Durable fistula closure occurred in the single patient who received argon plasma coagulation plus endoscopic suturing, whereas fistula dehiscence occurred in 3/3 (100%) patients with endoscopic suturing monotherapy.

Conclusions: Larger LAMS diameter (20-mm), longer LAMS dwell time, and spontaneous fistula closure may be technical factors that increase the likelihood of post-EDGE persistent fistula. Post-EDGE persistent fistula has not been shown by ours or other studies to be significantly associated with unintentional weight gain; however, this may be due to small sample size. We question the utility of routine fistula closure by primary intent and suggest a personalized approach to post-EDGE fistula management.