Continuing progress in endoscopic drainage of walled-off pancreatic necrosis

Endoscopic ultrasound (EUS)-guided drainage has evolved to become the preferred treatment modality for walled-off pancreatic necrosis (WON) [1] [2]. Historically, invasive surgery, percutaneous drainage, or endoscopic retrograde cholangiopancreatography (ERCP)-guided stent placements were utilized to treat WON, but these procedures were associated with high rates of adverse events [3] [4] [5] [6]. Advancements in stents and accessories have allowed for efficacious EUS-guided drainage of WON, especially the use of the large-diameter lumen-opposing metal stents and biflanged metal stents (BFMS) [7] [8]. However, several questions on their use remain: a) When should drainage be performed? b) How early should necrosectomy be performed? c) How can treatment response be predicted? d) When should the metal stent be removed? e) What is the role of ERCP in cases with pancreatic duct leaks? f) How should recurrence be managed.

In this issue of the Endoscopy, Dhir et al. attempt to address two of these important questions: the timing of BFMS removal in WON, and the role of ERCP for pancreatic duct stenting in cases of WON with pancreatic duct leaks [9]. The authors performed a prospective, single-center, observational study involving 88 patients. The following findings were reported: a) short-term use (median 3.5 weeks, range 3 – 17 weeks) of BFMS (16 mm, Nagi Stent; Taewoong, Seoul, Korea) was effective to treat WON; b) recurrence occurred equally in patients with and without pancreatic duct stenting for pancreatic duct leaks; c) most recurrence developed 6 months after BFMS removal and regressed spontaneously without therapy.

“The study by Dhir et al. provides important information showing the efficacy of biflanged metal stents in the treatment of walled-off pancreatic necrosis.”

The authors are to be commended for conducting a large prospective study with a relatively long follow-up period on a relatively rare disease. Certain aspects of the study are to be noted. First, experienced endoscopists with expertise in WON management performed the procedures. They carefully selected the patients and followed a rigorous protocol for necrosectomy and ERCP leading to early BFMS removal. Second, a higher rate of pancreatic ductal disconnection (61 %) and leak (70 %) was observed, and magnetic resonance cholangiopancreatography (MRCP) was not accurate in diagnosing pancreatic duct leaks compared with ERCP. However, the cause for the low diagnostic accuracy of MRCP was not detailed in the study. Third, the recurrence rate was only 9 %, despite the high rate of pancreatic duct leaks. Although the authors inferred from their observation that pancreatic stenting did not influence the recurrence rate, it appears that stenting may have lowered the recurrence rate to some extent. A randomized study will be necessary to inform us of the role of stenting. Finally, a high rate of adverse events occurred in the study, despite meticulous pre-treatment evaluation. This is not surprising, as most prior studies were primarily retrospective with a smaller number of patients. The authors took special care to look for pseudoaneurysms within the cyst, and the presence of collateral vessels from splenic vein thrombosis before BFMS placement. Despite such rigorous measures, bleeding occurred in 3 % of cases. Further studies to identify the risk factors and the best modality to detect aneurysms are desirable.

Good progress continues to be made in the development of an effective endoscopic therapy for WON. In many parts of the world, the purchasing power of the patient is relatively low. In this setting, treatment of WON using BFMS is likely to be a dominant strategy – a strategy that offers improved efficacy at lower cost [10]. The study by Dhir et al. provides important information showing the efficacy of BFMS in the treatment of WON.

• References

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