Revolutionizing palliative care: Electrocautery-enhanced lumen-apposing metal stents in endoscopic-ultrasound-guided biliary drainage for malignant obstructions

Abstract

Patients with malignant biliary obstruction, following endoscopic retrograde cholangiopancreatography (ERCP) failure could be referred for endoscopic-ultrasound-guided biliary drainage through electrocautery-enhanced (ECE) lumen-apposing metal stent (LAMS) placement. However, the efficacy and safety of ECE-LAMS in this scenario have remained debatable due to minimal scientific evidence. The current confirmed 91.0% clinical success, 96.7% technical success, 7.3% reintervention rate, and 17.5% adverse events, following the treatment of malignant biliary obstruction with ECE-LAMS delivery. Finally, ECE-LAMS proved to be a generalizable strategy for managing biliary obstruction for patients who were excluded from ERCP.

Key Words: Endoscopic retrograde cholangiopancreatography; Electrocautery-enhanced-lumen-apposing metal stent; Biliary drainage; Biliary stent; Endoscopic ultrasound

Core Tip: The ultrasound-directed electrocautery-enhanced-lumen-apposing metal stent placement is a viable approach for malignant biliary obstruction treatment in patients who do not qualify for endoscopic retrograde cholangiopancreatography (ERCP) or in those with ERCP failure. This finding relies on the acceptable reintervention rate, greater clinical success, and manageable/low adverse events, obtained in the current study.

TO THE EDITOR

We recently had the opportunity to read the current study “Endoscopic-ultrasound-guided biliary drainage (BD) with the placement of an electrocautery-enhanced lumen-apposing metal stent for palliation of malignant biliary obstruction”, recently published in the World Journal of Gastrointestinal Surgery. Peng et al[1] did a literature search of the published articles on endoscopic-ultrasound-guided BD (EUS-BD) using electrocautery-enhanced (ECE) delivery of lumen-apposing metal stent (LAMS) for malignant biliary obstruction, following the endoscopic retrograde cholangiopancreatography (ERCP) failure.

Although ERCP-guided BD is the gold standard for treating distal malignant biliary obstruction[2], several challenges including ampulla obscured by prior stents, tumoral involvement of the papilla, surgically altered anatomy, and gastric outlet obstruction add to the 15% failure rate of this procedure[3-6]. The percutaneous transhepatic BD (PTBD)/surgical bypass had been the alternative approach in failed ERCP cases; however, high (i.e., 60%) adverse event rates, including major complications and mortality, restrict the use of this strategy despite its high technical success[7-11].

Recent studies have shown reduced reintervention rates, low adverse events, and higher clinical success of EUS-BD vs PTBD[12,13]. However, deploying conventional stents with EUS-BD assistance appears challenging due to intricate steps and safety concerns. The placement of LAMS became a single-step procedure in 2013 with the advent of ECE technology[14]. ECE-guided LAMS placement has now been increasingly used for the past 2 years in several tertiary settings, for patients with malignant biliary obstruction who do not qualify for ERCP. The authors of this study recently analyzed ECE-LAMS placement for BD via EUS-guided choledochoduodenostomy, and the findings of this study motivated them to further evaluate ECE-LAMS-based EUS BD in failed ERCP cases.

Compared to the prior meta-analysis by Peng et al[15], based on 270 patients/six studies, the current study had a high statistical power since it investigated a large sample of patients (n = 620) and utilized more stringent inclusion/exclusion parameters in comparison to contemporary studies[1,15]. The principal findings of the current study confirmed the successful management of biliary obstruction through ECE-LAMS in patients who could not qualify for ERCP. The current study provides compelling evidence concerning the ongoing enhancement in the BD approaches for malignant biliary obstruction palliation. Findings from this study also provide insights into the BD management of a range of malignant conditions, such as ampullary cancer, metastatic cancer, cholangiocarcinoma, and pancreatic cancer, with duodenal stenosis.

Most of the studies in the current study were of high quality in terms of their design and evidence, measured by the median MINORS quality score. Importantly, a statistically significant high technical success rate (96.7%) and clinical success rate (91.0%) of EUS-BD-guided ECE-LAMS placement were reported[1]. Notably, no publication bias was reported. Adverse events, including stent occlusion, cholangitis and bleeding, were reported in 17.5% of patients receiving the ECE-LAMS placement. However, 7.3% of the treated patients required reintervention for clinical complications[1].

It is important to note that the technical and clinical success rates of ECE-LAMS placement in the current study were significantly higher than in the contemporary studies[1,16]. The findings supported the worldwide reproducibility and generalizability of ECE-LAMS placement, with minimal endoscopist training, for malignant biliary obstruction based on consistent clinical efficacy and technical success. Of note, the low adverse event rate observed in the current study aligns with current evidence, thereby confirming the safety of the ECE-LAMS procedure. However, the 17.5% adverse event rate in the current study warrants further investigation to delineate its potential causes, such as stent migration and recurrent cholangitis/cholecystitis[1]. Future studies should also evaluate the potential of using ECE-LAMS for a double-pigtail plastic stent placement to minimize mechanical complications and recurrence rates.

Few studies have correlated ECE-LAMS-related adverse events with the small diameter of the LAMS. However, they do not demonstrate the possible impact of stent diameter on the technical success of EUS-BD-guided ECE-LAMS placement[17,18]. Few other studies claim the use of this procedure as a bridge treatment, before any surgical intervention, for malignant biliary obstruction[17,19]. Another study also compared the EUS-CDS with LAMS and ERCP-M (metal stenting) for the management of malignant distal biliary obstruction. The technical success rate for EUS-CDS with LAMS was higher when compared to ERCP-M (90.4% vs 83.1%) and there were no significant procedure-related adverse events between the two methods[20]. For example, EUS-BD-guided ECE-LAMS placement could be deployed for patients with malignant biliary obstruction, who are scheduled for pancreatoduodenectomy. The current study recommends the need to examine the extent of pancreatoduodenectomy and the selection of space between the common bile duct and duodenal bulb for deploying the ECE-LAMS through EUS-BD guidance[1]. The primary aim of ECE-LAMS placement before pancreatoduodenectomy should be to avoid postprocedural cholangitis and consequent mortality. Authors of the current study further recommend multidisciplinary consultation for the management of malignant biliary obstruction.

Finally, the current study advocated the safety and efficacy of ECE-LAMS in patients who were excluded from ERCP treatment. The authors emphasized standardizing ECE-LAMS placement for malignant biliary obstruction in tertiary care settings. Despite the strong conclusions from the current study, its findings cannot be generalized for all patients with malignant biliary obstruction due to several potential limitations. For example, the current study could not uniformly define the clinical success of EUS-BD-guided ECE-LAMS placement and the incident study design hindered the heterogeneity assessment of the included studies[1]. Selection bias, due to the retrospective design of studies, increased the risk of selection bias. Importantly, the findings of this study could not be validated for patients treated in lower-level centers or local hospitals.

The robust outcomes of the current study correspond to its high methodological quality but require validation to determine the scope of using ECE-LAMS as a bridge to surgery approach or first-line treatment for malignant biliary obstruction. Accordingly, this approach could be standardized irrespective of the ERCP eligibility of patients scheduled for surgical intervention. Notably, the current findings should be reinvestigated by prospective observation studies, with large sample sizes, to optimize the use of EUS-BD-guided ECE-LAMS placement against malignant biliary obstruction in the tertiary centers. We also recommend the subgroup analyses of the current findings based on patient age, gender, baseline total bilirubin, baseline C-reactive protein, BD indication (i.e., cancer type), prior chemotherapy/radiotherapy, stent size, and past treatments. The corresponding results will help to personalize EUS-BD-guided ECE-LAMS placement based on demographic and baseline procedural characteristics[20]. We further recommend the reassessment/evaluation of the adverse event rate, hospital stay duration, and overall survival in patients treated with EUS-BD-guided ECE-LAMS placement, for malignant biliary obstruction.