Supplementary Material for: Repeated delayed bleeding following treatment for a pancreatic pseudocyst during lumen-apposing metal stent placement: A case report

Introduction: Lumen-apposing metal stent (LAMS) is a novel prosthesis for fistula formation between the gastrointestinal and cyst walls. Bleeding complications occur in 10% of cases mostly during LAMS placement. We present a case of recurrent bleeding following LAMS placement.
Case Presentation: A 47-year-old male was admitted to a local hospital for acute pancreatitis and subsequently referred for endoscopic drainage because of an enlarging pseudocyst near the tail of the pancreas. Treatment involved LAMS and endoscopic ultrasound-guided transmural drainage (EUS-TD). Post-treatment computed tomography revealed cyst shrinkage; however, upper gastrointestinal bleeding was noted after discharge. Endoscopy identified bleeding within the fistula, which was controlled by spraying an absorbable local hemostatic agent into the cavity. After ensuring the absence of recurrent bleeding for approximately one month, the LAMS was removed under endoscopy. Following LAMS removal, arterial bleeding was observed within the cavity, prompting an emergency angiography. Angiography revealed bleeding from a pseudoaneurysm of the splenic artery, which was treated with coil embolization. No rebleeding occurred after the procedure.
Conclusion: Bleeding complications occur in 10% of LAMS placements, primarily during the procedure. Bleeding one week after placement or during removal is rare. However, following LAMS placement, there is a risk of bleeding until removal, with arterial bleeding often occurring at the time of removal. Therefore, it is necessary to establish a system that allows for prompt vascular embolization treatment.