Background: Argon plasma coagulation (APC) of the gastrojejunal anastomosis (GJA) has been proposed as a therapy for weight regain after RYGB. Optimal settings and predictors of success remain unknown. Aim: (1) To assess efficacy of APC and compare outcomes of different APC settings (2) To determine predictors of weight loss after APC. Methods: This was a retrospective analysis of prospectively collected data on RYGB patients who underwent APC for weight regain. Technique: The GJA rim was circumferentially ablated using a straight-fire APC catheter. Patients underwent repeat procedure every 10-12 weeks. The high-and low-dose APC settings were 80W and 55W or lower, respectively. Sequential APC was defined as low dose followed by high dose APC. Primary outcome: Percentage total weight loss (%TWL) at 6, 12, 24 months. Secondary outcomes: Serious adverse event (SAE) rate and predictors of weight loss at 12 months. Statistics: Means were compared using a paired Student's t-test. Linear regression analyses were used to determine predictors of weight loss. Results: 200 RYGB patients with weight regain underwent 474 APC sessions (2.3AE1.7 sessions/patient). Of 200, 87 (43.5%), 55 (27.5%) and 58 (29%) underwent APC using low dose, high dose and sequential therapy. Baseline characteristics were similar across groups (Table 1). Primary Outcome: At 6, 12 and 24 months, 87.7%, 67.0% and 59.6% lost weight. Weight loss for the entire cohort was 6.8AE6.9 kg, 3.9AE9.2 kg and 3.7AE9.4 kg at 6, 12 and 24 months, respectively (p<0.01 for all). This corresponded to 6.8AE6.5%, 3.8AE8.8% and 4.1AE9.8% TWL at 6, 12 and 24 months. There was a trend towards greater weight loss with sequential therapy compared to low dose APC (pZ0.08) (Table 1). Oneyear data on high dose APC is pending. Secondary Outcomes: SAE rate per patient was 10.5% (21/200 cases). These included 14 GJA stenosis requiring balloon dilation or lumen apposing metal stent (7%), 4 GI bleeding from marginal ulcer requiring hemoclips and epinephrine injection (2%) and 3 cases of esophagitis (1.5%). SAE rate by session was 4.1% (19/474 sessions), representing a 3% rate for low dose APC (1.2% GJA stenosis, 0.9% GI bleeding, 0.9% esophagitis) and an 8.5% rate for high dose APC (7.8% GJA stenosis, 0.7% GI bleeding) (pZ0.001) (Table 2). On univariable regression, amount of weight regain, history of suturing prior to APC and reduction in GJA size were significant predictors of amount of weight loss at 12 months. These remained significant after controlling for age, sex and BMI (bZ0.2, -13.2, 10; pZ0.05, 0.001, 0.01, respectively). Conclusion: APC appears to be effective at treating weight regain up to at least 2 years. There is a trend towards greater efficacy with sequential APC therapy. Reduction in GJA size and prior history of suturing are positive and negative predictors of APC-induced weight loss.
