SILENCE OF THE LAMS: REDUCING RISK IN EUS GUIDED DRAINAGE OF PANCREATIC FLUID COLLECTIONS

Introduction and Aims

Endoscopic ultrasound guided transmural drainage (ETD) followed by endoscopic transluminal necrosectomy (ETN) is the evidence based preferred modality of treatment for symptomatic pancreatic fluid collections (PFC). EUS guided insertion of a lumen apposing metal stent (LAMS) facilitates improved drainage of fluid and improves efficacy of ETN. There is recognised risk associated with the procedure, primarily including bleeding, stent displacement and buried stent. Recent ESGE guidelines on the management of acute necrotising pancreatitis describe the use of imaging prior to drainage and at a 4 week interval, primarily to quantify the solid component in the collection. No definitive imaging protocols are established. In our institution, a protocol was developed to reduce the risk of adverse events associated with drainage. This included pre-intervention arterial phase CT and if identified, prophylactic embolisation of underlying pseudoaneurysm. In addition, all patients underwent CT at 4-5 weeks post stent insertion to determine efficacy of drainage and quantify residual component to determine benefit of long term plastic stents. We sought to assess the impact of the protocol on reducing LAMS associated adverse events.

Methods

We evaluated our practice over a two year period between November 2018 and 2020. Prospectively collected data was reviewed retrospectively for the rates of technical success, clinical success and adverse event.

Results

A total of 56 ETD procedures were performed on 52 patients. The majority of patients in the cohort were male (70.6%) with a mean age of 58 years. All patients underwent an arterial phase CT prior to ETD. Nine patients (17.3%) required embolisation of a previously unrecognised pseudoaneurysm prior to ETD. All procedures were technically successful (100%). Thirty five (67.3%) patients underwent a single ETN and 10 (19.2%) had multiple ETN procedures. Twenty two (62.8%) patients had a 20mm lumen diameter stent inserted and the remainder 15mm. Forty eight patients (92%) achieved complete resolution of collection with a single stent. Four patients (8%) required either an additional stent (multi-gated approach) or additional percutaneous drain. Stent dislodgement occurred in 4 (7.6%) patients during ETN. The median duration of LAMS placement was 44 days. No procedural or delayed LAMS related complications occurred.

Conclusion

Appropriate pre-procedural cross-sectional imaging facilitates identification and treatment of underlying pseudoaneurysm in this complex patient group. Post procedure interval imaging enables quantification of the residual collection to determine the benefit of long term plastic stents or additional drainage procedure. Our experience suggests adherence to a rigorous imaging protocol may reduce the risk of complication associated with LAMS deployment.