Lumen-Apposing Metal Stent Bleeding Risk: Management of Splenic Artery Erosion

ABSTRACT

Lumen-apposing metal stents (LAMS) have been used for drainage of peripancreatic collections, although they may be associated with complications, including bleeding. We report a case of a 49-year-old male patient who developed hematemesis and syncope three and a half weeks after LAMS placement for peripancreatic collection drainage. A computed tomography scan revealed splenic artery erosion by the distal flange of the stent. Splenic artery embolization was performed before LAMS removal, and splenectomy was required 3 days later. The patient remains asymptomatic after two years of follow-up. This case demonstrates an approach to a rare but potentially fatal complication of LAMS.

INTRODUCTION

Peripancreatic collections may require drainage when they become symptomatic, infected, or start compressing adjacent organs.¹ This procedure can be performed by placing multiple double-pigtail stents, fully covered self-expanding metal stents, or by lumen-apposing metal stents (LAMS).²

LAMS have been increasingly used for peripancreatic collections management, as it seems to have higher clinical success rates, less endoscopy sessions, and shorter procedure times and hospital stays, when compared with plastic stents.³ LAMS are biflanged-shaped with a large stent diameter which allows a better drainage of necrotic debris and for direct endoscopic necrosectomy, although it may has been associated with increased incidence of adverse events (bleeding, stent migration, stent occlusion, and buried stent syndrome), particularly in cases of long indwell times.⁴

Bleeding risk is thought to be associated with the collapse of the cyst cavity after deployment of LAMS. Friction between the metal stent and the cavity wall can cause trauma, leading to erosion, pseudoaneurysm formation, and subsequent bleeding. This complication can occur in up to 25% of patients.^4–6

We present a case report and a possible management approach to this life-threatening complication.

CASE REPORT

A 49-year-old male patient was diagnosed with a single episode of idiopathic acute necrotizing pancreatitis. During the initial admission, a comprehensive diagnostic work-up was conducted to identify the etiology of acute pancreatitis. The patient had no history of alcohol use, trauma, or prior endoscopic retrograde cholangiopancreatography and reported no use of medications associated with pancreatitis. Serum calcium, triglyceride, and IgG4 levels were within normal limits. Infectious causes, including viral, fungal, and parasitic infections, were excluded. There was no evidence of biliary stones. Magnetic resonance cholangiopancreatography showed no anatomic pancreatic abnormalities, apart from the noted pancreatic necrosis, without other complications. There was no prior history of pancreatitis.

He remained asymptomatic after discharge until one month before his scheduled follow-up appointment, when he began experiencing postprandial fullness. There was no associated nausea, vomiting, or weight loss. Nutritional assessment using the Malnutrition Universal Screening Tool yielded a score of 0, indicating low risk of malnutrition. Laboratory evaluation revealed new-onset thrombocytopenia.

A follow-up abdominal computed tomography (CT) scan revealed a large peripancreatic fluid collection, measuring 175 × 149 × 240 mm, consistent with a mature pancreatic pseudocyst. The collection exhibited a well-formed, encapsulated wall and was compressing the splenomesenteric confluence. On this imaging study, the splenic artery was noted to course along part of the posterior wall of the fluid collection, situated on the side opposite the gastric interface.

An endoscopic ultrasound-guided transgastric drainage of the collection was performed using a 20 × 10-mm lumen-apposing metal stent (Hot AXIOS, Boston Scientific Corporation, Marlborough, MA). Doppler imaging revealed no vessels in the vicinity of the intended site of stent deployment. Nonpurulent fluid drainage was observed.

Three and a half weeks later, the patient presented with hematemesis and syncope. He was normotensive and tachycardic (104 bpm). Blood tests showed a hemoglobin level of 9 g/dL on admission (a drop of 3 g/dL from the previous value).

The esophagogastroduodenoscopy revealed well-positioned LAMS on the posterior face of the upper body, with organized clots in its lumen, without active bleeding (Figure 1). The abdominal CT scan revealed the distal flange eroding the splenic artery (Figure 2). At that time, the pancreatic fluid collection measured approximately 37 × 53 × 17 mm, with enhancing walls and heterogeneous, spontaneously hyperdense content, suggestive of hemorrhagic material.

Figure 1.

Upper endoscopy showing organized clots within the lumen of the stent, with no evidence of active bleeding.

Figure 2.

Computed tomography scan images demonstrating close apposition of the lumen-apposing metal stent with splenic artery (red arrow).

It was decided to embolize the splenic artery before removing the LAMS due to the high risk of severe hemorrhage associated with splenic artery erosion. A vascular plug (Amplatzer 12 mm; Abbott, Plymouth, MN) was placed through the right humeral artery (Figure 3).

Figure 3.

(A) Selective catheterization of splenic artery, showing its compression and abnormality (red arrow) caused by the lumen-apposing metal stent (yellow arrow). (B) Successful 12-mm Amplatzer insertion (red arrow) into splenic artery, in close apposition with the stent (yellow arrow). Hepatic artery and the proximal splenic artery patency proximal to the vascular plug.

The LAMS was successfully removed without complications. A large nonbleeding vessel was observed inside the cavity (Figure 4). The patient was monitored in the intensive care unit. Three days after splenic artery embolization and stent removal, the patient developed fever with evidence of splenic necrosis on CT scan. Splenectomy was performed. No further interventions were necessary after splenectomy.

Figure 4.

Large non-bleeding vessel within the cavity.

Despite the large size of the collection, the patient maintained adequate nutritional status throughout the course of the illness and did not require parenteral nutritional support. Oral intake was initiated the day after splenectomy, beginning with a liquid diet and enteral supplementation. The patient had a favorable clinical evolution and remains asymptomatic in a two-year follow-up.

DISCUSSION

Endoscopic ultrasound-guided LAMS placement has become the standard of care for managing peripancreatic collections, due to its efficacy and safety profile.^2,6 Despite the fact of the advantages of LAMS, stent-related bleeding has been reported.⁷

Alternative stents, such as Spaxus stent (Taewoong Medical, Gimpo-si, South Korea), show promise in reducing the risk of bleeding, when compared with HotAXIOS, potentially due to their design features, characterized by rounded edges and foldable flanges, allowing accommodative apposition between the stent and the cavity wall.⁸

Double-pigtail plastic stents (DPPS) offer a softer, more flexible option than LAMS that may further mitigate vascular complications.⁶ The simultaneous placement of (DPPS) across LAMS has been proposed, but its routine use is not yet standard practice, since some studies showed no difference on bleeding rates between coaxial placement of DPPS within a LAMS and LAMS placement alone.⁵

Other strategies to reduce LAMS-associated complications are being actively explored. Some authors also suggest shorter-interval hemoglobin evaluation and imaging, particularly for patients with peripancreatic collections extending into the paracolic gutter, as these patients are believed to have a higher risk of LAMS-associated bleeding.⁹

Most LAMS-related adverse events are more common after three weeks of stent placement. To enhance safety, an increasing number of authors suggest performing CT scan three weeks postprocedure to plan stent removal if the cyst collapse is demonstrated.⁴ Currently, it is recommended to remove the LAMS within four weeks to reduce these risks.¹⁰

Although several factors can contribute to splenic artery erosion, in this case, the most relevant appears to be the subsequent contact between the splenic artery and the distal flange of the LAMS following cavity collapse. Predrainage imaging did not suggest a close relationship between the splenic artery and the gastric wall.

Although the stent was removed within the timeframe recommended by current guidelines, earlier removal could potentially have been considered. An interim imaging study might have revealed near-complete drainage of the collection, supporting earlier intervention. These findings highlight that, even when initial imaging does not indicate immediate vascular risk, rapid cavity collapse may pose a delayed threat. Thus, thorough assessment of vascular anatomy before drainage and close postprocedural monitoring are crucial to help prevent this severe complication.

This case demonstrates a massive gastrointestinal bleeding due to erosion of splenic artery secondary to LAMS placement. Managing these situations is not always clear, but the splenic artery embolization seems to be determinant for a successful outcome.

Additional studies are needed to identify which patients are at higher risk and which methods could minimize delayed adverse effects associated with LAMS.

DISCLOSURES

Author contributions: F. Côrte-Real: Contributed to the conception and design of the case report, collected clinical data and literature, and wrote the first draft of the manuscript. AC Rego: Participated in the acquisition and interpretation of clinical data and critically revised the manuscript for important intellectual content. AR Silva: Reviewed patient imaging, contributed to figure preparation, and revised the manuscript critically. N. Amaral: Assisted with literature review and reviewed the manuscript. N. Nunes: Provided clinical guidance and reviewed the manuscript for accuracy and clarity. JR Pereira: Supervised the project, provided clinical guidance, and reviewed the manuscript for final approval. MA Duarte: Ensured the integrity of the case report, and takes full responsibility for the content as the article guarantor.

Acknowledgments: We thank all the collaborators who cooperated in the treatment of this patient.

Financial disclosure: None to report.

Previous presentation: XXXVIII Annual Meeting of the Núcleo de Gastrenterologia dos Hospitais Distritais, held on October 27–28, 2023, in Penafiel, Portugal.

Informed consent was obtained for this case report.

ABBREVIATIONS:

CT

computed tomography

DPPS

double-pigtail plastic stents

LAMS

lumen-apposing metal stents