Introduction LAMS are increasingly used for the drainage of pancreatic fluid collections (PFC). Non-infective complications i.e. migration, bleeding, tissue overgrowth and perforation is reported in 5 - 25%. We report results from the largest UK & Ireland multicentre study on the incidence of non-infective complications with LAMS.

Method Retrospective study from a prospectively maintained database in 15 NHS hospitals in the UK & Ireland. Data collected include demographics, aetiology, severity of pancreatitis, type & size of PFC, immediate (< 24 hours), short term (< 7 days) & long term complications, recurrence of PFC and mortality. Minimum follow up was 4 months.

Results 823 LAMS were inserted from November 2015 to October 2019. Median age = 53 yrs. (IQR = 37.2 – 69.1). M: F = 502:321. Gall stones (46%) & alcohol ((29%) were the commonest aetiology. Severity of pancreatitis data was available in 85% 1. Mild = 24%, moderate = 35% & severe = 26%. Median size of the PFC was 11 cm (IQR –7.4 – 15.32). 48% were pseudocysts, 49% walled of necrosis & 3% acute necrotic collection. 87% were done in the endoscopy unit with 72% under conscious sedation. Technical success was 98% (809/823). Immediate complications was seen in 29(3.5%) including bleeding (9), maldeployment (19) and sedation related (1). Short term complications were seen in 25(3%) including malposition (3), bleeding (9), pain (3) & migration (10). Late complications were seen in 143(17%) including buried stents as a result of tissue overgrowth 37(4.5%); migration 93(11%) - internal i.e. into the PFC = 27; external = 66, blocked stent 11(1.2%) & bleeding -2(0.2%). LAMS could not be removed in 8/823 patients (0.9%) but was successfully removed in 86%. Median removal time was 7 weeks (IQR = 6–7) & 7 weeks (IQR = 6–9) in patients with late complications. 2% were lost to follow up. Clinical success (complete resolution of PFC) seen in 729(89%) patients. Recurrence of PFC was seen in 3.2%. Median time of removal in patients with recurrence was 5 weeks (IQR – 1.9–8.1) compared to 7 weeks(IQR – 1–15; p> 0.076) in the patients who didn’t have recurrence of PFC. All-cause mortality was 7.4%. There was only one LAMS related death as a result of uncontrolled bleeding following deployment. Multivariate analysis did not show any statistically significant difference between any of the parameters resulting in the complications.

Conclusion In the largest multicentre series to date; we conclude that LAMS is effective in drainage of PFC. The incidence of immediate and short term complications is low. There is a high rate of late complications including migration, tissue overgrowth and bleeding. Recurrence of PFC does not seem to be related to timing of LAMS removal.