Plastic stents for refractory pancreatic duct strictures in chronic pancreatitis: the more the merrier

Pancreatic duct strictures due to chronic pancreatitis are often the most difficult for endoscopists to successfully remediate. There are multiple reasons for the suboptimal success rates for endoscopic therapy in this patient population, but one plausible explanation is that treating providers do not place large enough diameter stents for a prolonged duration.

In this issue of Endoscopy, Tringali et al. present a long-term retrospective study of patients who underwent multiple plastic stenting for refractory pancreatic duct strictures associated with chronic pancreatitis [1]. The study included patients with a dominant stricture in the head of the pancreas with symptoms of recurrent pain and evidence of persistent stricture despite two prior treatments with a single large-caliber (≥ 8.5 Fr) plastic stent for 3 months. In total, 48 patients were treated over the 18.5 – year study period with balloon dilation of the stricture followed by insertion of a median number of 3 plastic stents, which remained in place for 6 – 12 months. The authors found that this paradigm resolved the pancreatic duct stricture in 83 % of patients with a single session and 90 % with two sessions. During a mean follow-up of 9.5 years, 74 % of patients remained asymptomatic. Of note, patients with pancreatic head calcifications had lower success rates with this treatment strategy (75 % vs. 97 %; P  = 0.02). Nonetheless, the authors suggest that multiple pancreatic stent placement should be the standard of care rather than surgical intervention in this select patient population.

In fact, the same group demonstrated similar efficacy with the identical treatment strategy for refractory pancreatic duct strictures due to chronic pancreatitis in the head of the pancreas in a study published over a decade ago [2]. So why is there still a question about the best way to manage patients with chronic pancreatitis-related pancreatic duct strictures in the head of the pancreas? The simple answer is that very few patients fall into this category and therefore it is difficult to develop a best-practice paradigm. In this study at a high-volume center over an 18.5-year period, the majority of patients were successfully managed with a single large-caliber pancreatic duct stent. Only 13 % of patients (48/375) undergoing therapeutic endoscopic retrograde cholangiopancreatography (ERCP) for chronic pancreatitis were managed with multiple plastic pancreatic duct stents.

“...this study reiterates the notion that with adequate diameter and duration of stenting, a single stent is sufficient to manage most patients with pancreatic head strictures due to chronic pancreatitis.”

Given the relative lower frequency of chronic pancreatitis-related pancreatic duct strictures referred for endoscopic management compared with biliary indications, many endoscopists, including those at low-volume or community-based practices, are likely to have inadequate exposure and may feel uncomfortable aggressively managing pancreatic duct strictures. Much of the aversion to working in the pancreas stems from the perceived increased risk of post-ERCP pancreatitis (PEP). However, the endoscopist has to remember that patients with chronic pancreatitis are very different from other patients undergoing ERCP and are less likely to develop moderate-to-severe PEP [3]. Furthermore, the incidence of PEP decreases with increased disease severity in chronic pancreatitis.

For those inspired to take on more endoscopic pancreatic duct work after reading this article, there are a few pearls of wisdom buried in the manuscript that are worth highlighting. As previously mentioned, most patients with pancreatic duct strictures from chronic pancreatitis respond to single-stent therapy. However, this only applies to large-caliber stents (≥ 8.5 Fr) because the typical 5 – or 7-Fr stents placed for preventing PEP will not result in meaningful stricture remediation. In addition, the stents need to dwell for up to a year in order to allow for proper tissue remodeling. When placing multiple stents in a tight stricture, the first stent placed is usually a bit longer in order to prevent in-migration during placement of subsequent stents. Finally, all patients in the Tringali et al. study experienced 24 – 48 hours of post-procedural abdominal pain that required nonsteroidal anti-inflammatory drugs or opiates. The patient should be advised to expect pain after the procedure, which may require hospitalization, and the physician should be prepared to adequately manage the patient’s post-procedural pain.

This study does not apply to patients with dominant strictures related to chronic pancreatitis in the body or tail of the pancreas. Endoscopic therapy with traditional ERCP seems to be less effective in these locations as it becomes more technically difficult to adequately stent tight strictures the further they are located from the ampulla. Fully covered self-expandable metal stents (FC-SEMS) are an alternative strategy for the endoscopic treatment of pancreatic head strictures and may be easier to place than multiple plastic stents. However, these stents have been associated with increased risk of adverse events, including inciting “de novo” strictures in the pancreatic duct [4] [5]. It may be another decade before we see an adequately powered head-to-head trial comparing FC-SEMS and multiple plastic stents for the management of benign pancreatic duct strictures.

For the time being, this study reiterates the notion that with adequate diameter and duration of stenting, a single stent is sufficient to manage most patients with pancreatic head strictures due to chronic pancreatitis. The European Society of Gastrointestinal Endoscopy suggests initial management of dominant main pancreatic duct strictures with a single 10-Fr plastic stent for one uninterrupted year, with stent exchange performed based on signs and symptoms of stent dysfunction [6]. For patients with refractory main pancreatic duct strictures in the head of the pancreas, multiple plastic stents may be the best endoscopic therapeutic option. Before convincing the patient that the more the merrier in terms of number of stents placed, both the endoscopist and the patient need to be prepared for short-term pain (up to 48 hours) in order to achieve long-term gain.

• References

• 1 Tringali A, Bove V, Vadalà di Prampero SF. et al. Long-term follow-up after multiple plastic stenting for refractory pancreatic duct strictures in chronic pancreatitis. Endoscopy 2019; 51: 930-935
• 2 Costamagna G, Bulajic M, Tringali A. et al. Multiple stenting of refractory pancreatic duct strictures in severe chronic pancreatitis: long-term results. Endoscopy 2006; 38: 254-259
• 3 Zhao ZH, Hu LH, Ren HB. et al. Incidence and risk factors for post-ERCP pancreatitis in chronic pancreatitis. Gastrointest Endosc 2017; 86: 519-524
• 4 Tringali A, Vadala di Prampero SF, Landi R. et al. Fully covered self-expandable metal stents to dilate persistent pancreatic strictures in chronic pancreatitis: long-term follow-up from a prospective study. Gastrointest Endosc 2018; 88: 939-946
• 5 Korpela T, Udd M, Lindstrom O. et al. Fully covered self-expanding metal stents for benign refractory pancreatic duct strictures in chronic pancreatitis. Scand J Gastroenterol 2019; 54: 365-370
• 6 Dumonceau JM, Delhaye M, Tringali A. et al. Endoscopic treatment of chronic pancreatitis: European Society of Gastrointestinal Endoscopy (ESGE) Guideline – updated August 2018. Endoscopy 2019; 51: 179-193