Prevention of pancreatic fluid collection recurrence after metal stent removal: plastic is not so fantastic!

Here is a debate that has been going on in therapeutic endoscopy rooms for many years: should plastic drainage stents be left in place after treatment of walled-of-necrosis (WON) and fluid collections? In the most recent large prospective study, disconnected pancreatic duct syndrome affected almost half of the patients (46.2 %) after acute necrotizing pancreatitis [1] and this has some bearing on treatment and outcome.

This debate requires us to confront relevant ideas and to distinguish the cautious endoscopist from the fierce one. The cautious endoscopist would justify their approach by explaining that a loss of continuity in the pancreatic duct leads to additional parenchymal flow of pancreatic fluid and significantly increases the risk of recurrence of collections after the first drainage. It is therefore obvious that the choice is either to carry out this drainage using plastic stents, which can be placed for a long duration, or to replace the dedicated metal stent, which makes necrosectomy easier initially but requires earlier removal and replacement with one (or more) plastic stents to avoid adverse events. The other endoscopist, however, would determine that the collection and the acute pancreatitis has led to destruction of the upstream disconnected pancreatic duct and that replacement of the metal stent by a plastic one therefore has no relevance, will only lead to loss of time, will generate additional costs, and will bring its own share of potential complications.

“...the recurrence rate and the impact of pancreatic fluid collections, even in cases of disconnected duct syndrome, do not seem to justify the placement of plastic stents after drainage by a metal stent.”

It must be noted that few randomized studies to date have addressed this question using rigorous methodology or a sufficient number of patients. Therefore, the results of the randomized controlled trial by Chavan et al. [2] in this issue of Endoscopy provide valuable data to inform and progress our debate. After 3 months of follow-up, the number of recurrences in both intention-to-treat (ITT) and per-protocol (PP) analyses was identical (3/52) in both groups of patients (with or without plastic stent inserted after removal of the metal stent in patients with disconnected duct syndrome). These results also remained comparable at 6 and 12 months. After 1 year of follow-up, a total of 20 patients (19.2 %) presented recurrence of a pancreatic fluid collection; although the proportion of recurrences in the group of patients who did not receive a plastic stent was almost twice as high (13 vs. 7) as in those who did, the difference remained nonsignificant in both the ITT (P = 0.14) and PP (P = 0.07) analyses. More interestingly, the clinical impact of recurrence and the need for reintervention were not significantly different between the patient groups (3/7 in the stent group and 4/13 in the no-stent group; P = 0.62).

So, what are the strengths of this trial? First, the definition of the disconnected pancreatic duct syndrome and the underlying pancreatic disease might have been in question in such a trial. However, no such criticism can be made of the study as, in all cases, the disconnection was confirmed by both magnetic resonance cholangiopancreatography and endoscopic retrograde pancreatography, and the etiologies of pancreatitis were comparable between the two groups of patients. The rigorous methodology and the sufficient number of included patients make the conclusions of the study robust. Obviously, these results cannot be transposed to patients with chronic pancreatitis where transpapillary endoscopic treatment allowing optimal ductal clearance is often required, as this will influence the risk of recurrence of the collections.

What should we ultimately take from these results? In my opinion, recurrence after short-term placement of a metal stent for drainage of a pancreatic fluid collection after acute pancreatitis in a patient with disconnected duct syndrome probably does not develop through the same mechanism as recurrence in patients who benefit from initial and long-term drainage with plastic stent(s); this latter scenario represents the technique most used in the literature on the subject. This reasoning is supported by the fact that insertion of a plastic stent into a collapsed cyst or virtual cavity after removal of the metal stent is not always easy, as evidenced by the rate of placement failure (11.5 %) in the Chavan et al. study, as well as by the findings that recurrence was just as frequent (or more frequent) regardless of whether the stent had migrated or of the number of stents placed (which may seem surprising from a physiopathological point of view). The point that remains to be clarified is probably the underlying disease and its evolution over time. The proportion of idiopathic pancreatitis in the series of Chavan et al. [2] still raises questions. The medical management of pancreatitis and its impact on recurrence are not discussed in the article and they could obviously influence the overall results; the recurrent collections, which in some cases were at a distance from the first, definitely do not seem to be solely linked to transmural material that may or may not have remained after the initial drainage. These elements should be considered in any future study investigating this topic.

To summarize, the plastic stent does not appear to be so fantastic. The recurrence rate and the impact of pancreatic fluid collections, even in cases of disconnected duct syndrome, do not seem to justify their placement after drainage by a metal stent.

Publication History

Article published online:
25 April 2022

• References

• 1 Maatman TK, Roch AM, Lewellen KA. et al. Disconnected pancreatic duct syndrome: spectrum of operative management. J Surg Res 2020; 247: 297-303
• 2 Chavan R, Nabi Z, Lakhtakia S. et al. Impact of transmural plastic stent on recurrence of pancreatic fluid collection after metal stent removal in disconnected pancreatic duct: a randomized controlled trial. Endoscopy 2022; 54: 861-868