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Lumen-apposing metal stent acted as an interim role in walled-off necrosis drainage
  1. Huiyun Zhu,
  2. Han Lin,
  3. Xiangyu Kong,
  4. Zhendong Jin,
  5. Zhaoshen Li,
  6. Yiqi Du
  1. Department of Gastroenterology, Changhai Hospital, Second Military Medical University (Naval Medical University), Shanghai, China
  1. Correspondence to Professor Zhaoshen Li, Department of Gastroenterology Changhai Hospital, Second Military Medical University (Naval Medical University) Shanghai China ; 15026921681{at} and Professor Yiqi Du, Department of Gastroenterology, Changhai Hospital, Second Military Medical University (Naval Medical University), Shanghai 200433, China; duyiqi006{at}

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Recently, Bang et al 1 conducted the first randomised trial on lumen-apposing metal stents (LAMS) versus plastic stents for endoscopic ultrasonography (EUS)-guided drainage of walled-off necrosis (WON), which provided significant information for the clinical application of LAMS. We agree with Bang et al 1 that the wider diameter of LAMS facilitates more rapid drainage of necrotic contents leading to faster WON resolution, and we agree that LAMS must be removed at 3 weeks postprocedure if the WON resolved. Our endoscopy centre observed LAMS-related adverse events, including stent buried in tissue2 and cardia occlusion,3 at more than 3 weeks postprocedure.

Bang et al 1 stated that disconnected pancreatic duct syndrome (DPDS) is an important but often overlooked symptom of EUS. Recently, the consensus guideline on interventional EUS made by the Asian EUS group pointed out that the risk of pseudocyst recurrence increases in patients with DPDS.4 However, to date, published studies on EUS-guided drainage of pancreatic fluid collections (PFC) rarely mentioned this risk.

The risks of perforation and peritoneal leakage of PFC contents are presumably less likely given the ‘lumen-apposing’ characteristic of LAMS. However, the unique LAMS (Hot AXIOS) used in the Bang et al 1 trial have thorns on both ends of the stents, which impinge on adjacent tissues increasing the risk of adverse events, especially bleeding.5 The LAMS used in our centre do not pose bleeding risks, however, we do not recommend leaving the stents in place for more than 1 month.6

Endoscopists have high technical requirements for EUS-guided drainage of PFC. Because LAMS are easier to place technically, they have recently been used as interim tools for WON drainage. Aburajab et al 7 reported that placing plastic stents across LAMS during drainage of pancreatic pseudocysts reduced the likelihood of postprocedure infection. A WON cavity with ‘two-way traffic’ helps debris exit even when the cyst wall has collapsed8 and may reduce the total cost of the procedure.

In addition, Rana et al 9 compared the efficacy and safety of LAMS and plastic stents for WON drainage. The morphological features of a WON influence the EUS procedure used, for example, a WON with a large size and more solid debris requires a more aggressive therapeutic method for a successful outcome.9 The use of a plastic stent for a WON with solid debris >40% would be predicted to fail to drain the WON. We suggest that the content of the cyst should be taken into account when selecting the stent and the drainage scheme.

Recently, LAMS have been used as interim tools for WON drainage, and if used properly, LAMS have been shown to be superior to plastic stents. Nevertheless, further prospective trials are still needed and LAMS stents must be removed within 1-month postprocedure.


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  • HZ, HL and XK contributed equally.

  • Contributors HZ, ZL and YD conceived and designed the study. ZJ performed the endoscopy procedures. HZ, HL and XK wrote the draft. All authors final approval of the letter. HZ, HL and XK contributed equally.

  • Funding This investigation is supported by the grant from National Clinical Research Center for Digestive Diseases of China (2015BAI13B08) and Dr Huiyun Zhu is supported by China Scholarship Council.

  • Competing interests None declared.

  • Patient consent Not required.

  • Ethics approval Shanghai Changhai Hospital Ethics Committee.

  • Provenance and peer review Not commissioned; internally peer reviewed.

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