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Bang et al 1 reported in Gut their recent experience with the Boston Scientific Hot AXIOS lumen-apposing metal stent (LAMS) in the treatment of walled-off necrosis (WON). They described a concerning 50% (6/12) rate of stent-related adverse events, in particular delayed bleeding (3/12) and buried stent syndrome (2/12). They postulated that rapid decompression of the WON facilitated by the wide-bore LAMS may lead to the LAMS impinging on the internal wall of the collection cavity resulting in damage to adjacent vasculature, causing haemorrhage, or inward migration of the outer flange of the stent causing buried stent syndrome. Previously Bang et al 2 reported outcomes of 20 patients treated with the Hot AXIOS LAMS compared with 40 patients treated with double pigtail plastic stents. 13/20 of the patients treated with a LAMS had WON, and the stent-related adverse event rate in that subgroup was 15.4% (2/13),2 significantly lower than the rate reported in their more recent report.1 In both cases, the distal (internal) flange migrated inwards through the necrotic cavity into the lesser sac but there were no reported incidents of delayed bleeding or buried stent syndrome.
There is currently an ongoing UK and Ireland multicentre study of the Hot AXIOS LAMS in the management of pancreatic fluid collections as alluded to in a recent letter toGut,3 and we have reported preliminary results in abstract form.4 Of almost 100 patients, there were 58 cases of WON. We have observed low rates of early and delayed complications in both WON and pseudocysts. In the WON group, the stent-related adverse event rate was 10.3% (6/58). These included one case of early haemorrhage that required gastric artery embolisation but we observed no delayed haemorrhages. There were five cases of outward stent migration into the gut lumen and no cases of inward migration or so-called buried stent syndrome. One occurred during a direct endoscopic necrosectomy and four occurred spontaneously.
Given the large disparity in stent-related adverse events reported in the two recent publications from Bang et al,2 we would be interested to know if, in retrospect, there are any identifiable differences in patient or collection characteristics in the two studies. For example, was there a difference in the nature of the WON collections in terms of size, percentage of necrotic content or timing of the drainage procedure relative to the index episode of pancreatitis? Were there any differences in procedural factors? We would welcome the authors' comments to help provide some further insight into this challenging patient group. We would also reiterate the need for further studies to help guide us regarding the safety, efficacy and exact role of LAMS and other fully covered self-expanding metal stents in the management of both pseudocysts and WON.
Contributors BMR, SVV and MTH were all involved in conception, drafting and final approval of the letter.
Competing interests None.
Provenance and peer review Not commissioned; internally peer reviewed.
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