Usefulness of a newly designed laser-cut metal stent with an anchoring hook and thin delivery system for EUS-guided hepaticogastrostomy in experimental settings (with video)

Usefulness of a dedicated laser-cut metal stent with an anchoring hook and thin delivery system for EUS-guided hepaticogastrostomy in malignant biliary obstruction: a prospective multicenter trial (with video)

BACKGROUND AND AIMS

EUS-guided hepaticogastrostomy (EUS-HGS) carries a risk of serious adverse events (AEs). A newly designed, partially covered laser-cut stent with antimigration anchoring hooks and a thin tapered tip (7.2F), called a Hook stent (Zeon Medical, Tokyo, Japan), has been developed to prevent serious AEs associated with EUS-HGS. The present prospective multicenter clinical trial evaluated the efficacy and safety of the Hook stent for EUS-HGS after failure of ERCP in patients with unresectable malignant biliary obstruction.

METHODS

The primary endpoint was the rate of clinical success, and secondary endpoints were the rates of technical success, AEs, recurrent biliary obstruction (RBO), procedure success without using a tract dilation device, reintervention for RBO, time to RBO, and overall survival (OS).

RESULTS

Thirty-eight patients underwent EUS-HGS using the Hook stent. The technical and clinical success rates in patients undergoing EUS-HGS were 100% and 92.1%, respectively. The procedure success rate without using a tract dilation device was 94.7%. Four patients (10.5%) developed early AEs, but there were no severe AEs such as stent migration. RBO developed in 26.3% of patients. Reintervention for RBO had a 100% success rate. The median time to RBO was not reached, and the median OS was 191 days.

CONCLUSIONS

EUS-HGS using the Hook stent demonstrated a high clinical success rate, low rate of early AEs, and an acceptable stent patency. The Hook stent is safe and feasible for use in patients undergoing EUS-HGS. (Clinical trial registration number: jRCT2052210020.).

Endoscopic biliary drainage for distal bile duct obstruction due to pancreatic cancer

Approximately 60% of pancreatic cancers occur in the pancreatic head and may present as obstructive jaundice due to bile duct invasion. Obstructive jaundice often leads to poor general conditions and acute cholangitis, interfering with surgery and chemotherapy and requiring biliary drainage. The first choice of treatment for biliary drainage is the endoscopic transpapillary approach. In unresectable tumors, self-expandable metal stents (SEMSs) are most commonly used and are classified into uncovered and covered SEMSs. Recently, antireflux metal stents and large- or small-diameter SEMSs have become commercially available, and their usefulness has been reported. Plastic stents are infrequently used in patients with resectable biliary obstruction; however, owing to the recent trend in preoperative chemotherapy, SEMSs are frequently used because of the long time to recurrent biliary obstruction. Endoscopic ultrasound-guided biliary drainage (EUS-BD) is often performed in patients who are not eligible for the transpapillary approach, and favorable outcomes have been reported. Different EUS-BD techniques and specialized stents have been developed and can be safely used in high-volume centers. The indications for EUS-BD are expected to further expand in the future.

Radial force and wire structure determine the onset of covered self-expandable metal stent migration in endoscopic ultrasound-guided hepaticogastrostomy: Measurement of sliding-resistance force using a porcine model

BACKGROUND

Self-expandable metal stent (SEMS) migration after endoscopic ultrasound-guided hepaticogastrostomy (EUS-HGS) is a severe complication. The migration risk could be related to the surface friction of SEMS, assumed to be affected by the wire structure and mechanical properties, including radial force (RF); however, their relevance remains unclear. This experimental study aimed to assess the mechanical properties of SEMS involved in the onset of stent migration by measuring the sliding-resistance force (SF) as the SEMS moves through the stomach wall.

METHODS

The SF of seven types of 8-mm diameter SEMS (four braided and three laser-cut types) and porcine stomach wall was measured with a universal testing machine. The SF of each SEMS was measured three times, and the average maximum SF (SFmax) was used for analysis. The correlation between SFmax and RF of each SEMS was evaluated.

RESULTS

SFmax and RF showed a very strong positive correlation (r = 0.92). Compared to the regression line predictions in the scatter plots of SFmax and RF, the SFmax of laser-cut and braided type SEMSs had positive and negative residuals, respectively.

CONCLUSIONS

Selecting a laser-cut type SEMS with a higher RF may more effectively prevent the onset of stent migration against the stomach wall in EUS-HGS.

Endoscopic ultrasound-guided hepaticogastrostomy vs. antegrade metal stent placement keeping an access route in patients with malignant biliary obstruction

BACKGROUND

Few studies have compared endoscopic ultrasound (EUS)-guided hepaticogastrostomy (HGS) with EUS-guided antegrade metal stent placement (AGMS). The purpose of this study was to compare times to recurrent biliary obstruction (TRBO) in patients who underwent HGS using metal stents (MS) and those who underwent AGMS keeping access routes with plastic stents (AGMS-AR).

METHODS

This study retrospectively evaluated consecutive patients who underwent HGS or AGMS between September 2016 and December 2022. TRBO, overall survival (OS), and adverse event (AE) rates were compared in the two groups. The risk factors for RBO were determined using a multivariable Cox proportional hazards model.

RESULTS

This study included 32 patients in the HGS group and 30 in the AGMS-AR group. Technical success rate was significantly higher in the HGS than in the AGMS-AR group (100 vs. 80%; P = 0.009). The technical success rate without tract dilation was significantly higher in the AGMS-AR than in the HGS group (83 vs. 38%; P < 0.001). RBO rates were significantly higher in the HGS than in the AGMS-AR group (53 vs. 17%; P = 0.024), whereas AE rates did not differ significantly. TRBO differed significantly in the HGS and AGMS-AR groups (159 days vs. not reached, P = 0.011), whereas OS did not differ significantly. Multivariable analysis revealed that HGS was an independent risk factor for RBO (hazard ratio, 6.48, P = 0.014).

CONCLUSION

TRBO was significantly longer in patients who underwent AGMS with PS than HGS. AGMS with PS may be effective after the failure of ERCP in patients with malignant biliary obstruction.

Safety of skipping the tract dilation step for EUS-guided biliary drainage in patients with unresectable malignant biliary obstruction (with video)

BACKGROUND

Thin delivery system stents can be inserted directly without the need for a tract dilation step and are expected to reduce bile leakage during endoscopic ultrasound-guided biliary drainage (EUS-BD). The present study retrospectively compared the safety and efficacy of EUS-BD using a thin metal stent (< 7.5 Fr) with those of EUS-BD using a conventional stent (≥ 7.5 Fr).

METHODS

The present study enrolled 112 patients who underwent EUS-BD using metal stents for unresectable malignant biliary obstruction between April 2016 and July 2022. The primary endpoint was the rate of adverse events (AEs). The secondary endpoints were clinical success rate, procedure time, procedure success rate in the absence of the tract dilation step, recurrent biliary obstruction rate, time to biliary obstruction, and overall survival. Risk factors associated with early AEs were also evaluated.

RESULTS

The rate of early AEs was significantly lower (12% vs. 35%, P = 0.013) and the procedure success without the tract dilation step was significantly higher (82% vs. 33%, P < 0.001) in the thin than in the conventional delivery system stent group. None of the other secondary endpoints differed significantly between the two groups. Multivariate analysis showed that employing the tract dilation step during EUS-BD was a significant independent risk factor for early AEs (skipping vs. employing; HR, 9.66; 95% CI, 1.13-83.0, P = 0.028).

CONCLUSION

Employing the tract dilation step during EUS-BD was a significant risk factor for early AEs. Metal stents with a delivery diameter < 7.5 Fr can be inserted directly without the tract dilation step, resulting in lower early AE rates.

Preliminary feasibility study of a new partially covered self-expandable metal stent with an anchoring flange for EUS-guided hepaticogastrostomy (with videos)

BACKGROUND AND AIMS

EUS-guided hepaticogastrostomy (EUS-HPG) has a risk of serious procedural adverse events (AEs), but few dedicated devices for EUS-HPG are available. We evaluated the feasibility of a new partially covered self-expandable metal stent (PCSEMS) with an anchoring flange for EUS-HPG.

METHODS

The feasibility of a stent featuring a proximal radiopaque uncovered portion 1.5 cm in length and a distal anchoring flange 20 mm in diameter was evaluated in consecutive patients undergoing EUS-HPG for unresectable malignant biliary obstruction. Primary outcomes were the technical and clinical success of EUS-HPG, and secondary outcomes were AEs, recurrent biliary obstruction (RBO), reintervention for RBO, and the technical feasibility of peroral cholangioscopy (POC) through the stent in situ.

RESULTS

EUS-HPG was performed in 24 patients with unresectable malignant biliary obstruction. The technical and clinical success rates of EUS-HPG were 100% (24/24) and 91.7% (22/24), respectively. AEs developed after EUS-HPG in 8.3% of patients (2/24, cholangitis). RBO developed in 29.2% of patients (7/24), with a median cumulative time to RBO of 6.7 months. The causes of RBO were sludge formation (n = 4), hyperplasia at an uncovered portion (n = 2), and nonocclusive cholangitis (n = 1). Reintervention for RBO had a 100% success rate (7/7), and POC through the stent in situ was technically feasible in 7 of 8 patients with a stent diameter of 10 mm.

CONCLUSIONS

EUS-HPG with a new PCSEMS can alleviate malignant biliary obstruction after failed ERCP. The novel stent evaluated in this study may prevent stent-related AEs, including stent migration, and allow advanced endoscopic interventions through the HPG route.

Prospective clinical trial of EUS-guided choledochoduodenostomy without fistula dilation for malignant distal biliary obstruction

Background and Objectives

During EUS-guided choledochoduodenostomy (EUS-CDS), fistula dilation before stent insertion is associated with adverse events (AEs), such as bile leakage and peritonitis. We hypothesized that EUS-CDS without fistula dilation using a novel self-expandable metal stent (SEMS) with a thin delivery system could overcome this problem, and we conducted this study to evaluate its feasibility and safety.

Methods

This was an open-label, single-arm, phase II study at a single institution. We planned EUS-CDS without fistula dilation using a fully covered SEMS with a 5.9-Fr delivery system for unresectable malignant distal biliary obstruction. The primary outcome was overall technical success. Secondary outcomes were technical success without fistula dilation, procedure time, functional success, time to recurrent biliary obstruction, and AEs. The planned sample size was 25 patients.

Results

In total, 24 patients were included in this study. In 21 patients, EUS-CDS was performed as primary drainage. The overall technical success rate was 100% (24 of 24 patients). The technical success rate without fistula dilation was 96% (23 of 24). The median procedure time was 16 min (range, 10-66 min). The functional success rate was 96% (23 of 24). The median time to recurrent biliary obstruction was 148 days (95% confidence interval, 29-266 days). There were no procedure-related AEs. Furthermore, computed tomography immediately after the procedure showed no leakage of contrast medium into the abdominal cavity in any patient.

Conclusions

EUS-guided choledochoduodenostomy without fistula dilation using a fully covered SEMS with a 5.9-Fr delivery system is feasible with a high probability and can be achieved quickly while effectively preventing bile leakage and peritonitis.

Development of devices for interventional endoscopic ultrasound for the management of pancreatobiliary diseases

A variety of devices have been developed for interventional endoscopic ultrasound (EUS). EUS-guided drainage of the bile duct and pancreatic duct, as well as fluid collection adjacent to the gastrointestinal tract, is performed by a procedure involving puncture, guidewire manipulation, tract dilation, and stent placement. Devices specialized for interventional EUS are being developed for each step of the procedure. Mechanical dilators such as bougie, balloon, and electrocautery dilators are used for tract dilation. Various types of plastic stents, self-expandable metal stents, and lumen-apposing metal stents specifically designed for interventional EUS are now available, including one-step devices developed to improve the efficacy and safety of interventional EUS. In addition, radiofrequency ablation and the placement of fiducial markers and radioactive seeds under EUS guidance are now becoming established for pancreatic neoplasms. Such development of specialized devices has expanded the indications for interventional EUS, increased the success rate, and lowered the adverse event rate.

Feasibility and efficacy of endoscopic reintervention after covered metal stent placement for EUS-guided hepaticogastrostomy: A multicenter experience

Background and Objectives

Although the use of a long metal stent is favored for EUS-guided hepaticogastrostomy (EUS-HGS) for the relief of malignant biliary obstruction (MBO), endoscopic reintervention (E-RI) at the time of recurrent biliary obstruction (RBO) is challenging due to a long intragastric portion. This study evaluated the feasibility and safety of E-RI after a long partially covered metal stent (L-PCMS) placement during EUS-HGS.

Materials and Methods

We performed a multicenter retrospective study between January 2015 and December 2019 examining patients with MBO who underwent E-RI for RBO through the EUS-HGS route after the L-PCMS placement. Technical and clinical success rates, details of E-RI, adverse events (AEs), stent patency, and survival time were evaluated.

Results

Thirty-three patients at eight referral centers in Japan who underwent E-RI through the EUS-HGS route were enrolled. The location of MBO was distal in 54.5%. The median intragastric length of the L-PCMS was 5 cm. As the first E-RI attempt, E-RI via the distal end of the existing L-PCMS was successful in 60.6%. The overall technical and clinical success rates of E-RI were 100% and 81.8%, respectively. Liver abscess was noted in one patient. A proximal biliary stricture was associated with the clinical ineffectiveness of E-RI in multivariable analysis (odds ratio, 12.5, P = 0.04). The median survival and stent patency duration after E-RI were 140 and 394 days, respectively.

Conclusions

Our study findings suggest that E-RI for RBO after EUS-HGS with a L-PCMS is technically feasible and clinically effective, without any severe AEs, especially for patients with distal MBO.

Current endoscopic approaches to biliary strictures

PURPOSE OF REVIEW

To summarize the current status and future perspectives of the endoscopic management of biliary strictures.

RECENT FINDINGS

In addition to conventional diagnostic modalities, such as cross-sectional imaging and endoscopic ultrasonography (EUS), per-oral cholangioscopy is helpful for indeterminate biliary strictures. It allows direct visualization of the biliary tract and targeted biopsy. For distal malignant biliary obstruction (MBO), a self-expandable metal stent (SEMS) via endoscopic retrograde cholangiopancreatography (ERCP) is a standard of care. EUS-guided biliary drainage (EUS-BD) is an emerging alternative to percutaneous transhepatic biliary drainage in cases with failed ERCP. EUS-BD is also an effective salvage option for perihilar MBO, which can not be managed via ERCP or percutaneous transhepatic biliary drainage. Preoperative drainage is necessary for most jaundiced patients as neoadjuvant chemotherapy is widely administered for resectable and borderline resectable pancreatic cancer, and a SEMS is preferred in this setting, too. For benign biliary strictures, a covered SEMS can improve stricture resolution and reduce the number of endoscopic sessions as compared to plastic stents.

SUMMARY

ERCP and EUS play a central role in the diagnosis and drainage for both malignant and benign biliary strictures.

Investigator initiated clinical trial to validate usefulness of specific system for endoscopic ultrasound guided hepaticogastrostomy (HG01) in malignant biliary obstruction (HG01)

INTRODUCTION

Endoscopic ultrasound-guided hepaticogastrostomy (EUS-HGS) is a novel drainage option for patients with an inaccessible papilla. Although EUS-HGS has clinical benefits in patients for whom endoscopic retrograde cholangiopancreatography (ERCP) has failed, the rates of adverse events (AEs) associated with EUS-HGS, such as bile peritonitis and stent migration, are higher than for other procedures. The development of a dedicated system for EUS-HGS is therefore desirable to reduce the rate of AEs. We developed a dedicated system for EUS-HGS (HG01 system) which is composed of a 19-gauge needle, 0.025-inch guidewire, a thin delivery system for tract dilation, and an antimigration metal stent. This study is designed to evaluate the efficacy and safety of EUS-HGS using the HG01 system in malignant biliary obstruction.

METHODS/DESIGN

This is a single-arm multicenter prospective study involving 40 patients across six tertiary centers in Japan. Patients with an unresectable malignant biliary obstruction in whom biliary drainage with ERCP failed, is not possible, or is very difficult will be registered in the study. The primary endpoint is the clinical success rate. The secondary endpoints are the technical success rate, procedure-related AE rate, procedure time, procedure success rate using only the HG01 system, stent patency rate, re-intervention success rate, re-intervention method, survival rate, and distance of movement of the stent position.

DISCUSSION

We expect use of the HG01 system to reduce the rate of AEs during EUS-HGS, especially bile leakage and stent migration. If the efficacy and safety of EUS-HGS using the HG01 system is confirmed in the present study, it is likely to be considered the first-choice device for use during EUS-HGS.

Newly Designed Laser-Cut Metal Stent with an Anchoring Hook and Thin Delivery System for Endoscopic Ultrasound–Guided Hepaticogastrostomy: Is It a Dream Stent?

Endoscopic ultrasound–guided hepaticogastrostomy (EUS-HGS) involves creation of an anastomosis between two intra-abdominal mobile organs, namely, liver and the stomach, with no intervening stricture. Therefore, the risk of stent migration in EUS-HGS is very high and the stent migration can lead on to severe life-threatening complications like biliary peritonitis. During last few years, there have been increased efforts to design a safe and effective stent for EUS-HGS that obviates the risk of stent migration and can also be inserted quickly, preferably, in a single-step procedure. In this news and views, we discuss an experimental study from Japan that has evaluated a new partially covered self-expandable laser cut metal stent with a thin delivery system (7.2 F) and antimigration anchoring hooks for single-step EUS-HGS in phantom and animal models.