Small cell- versus large cell-sized metal stent in endoscopic bilateral stent-in-stent placement for malignant hilar biliary obstruction

Efficacy of a novel large-cell Niti-S stent with a slim delivery system for hilar biliary obstruction: a preliminary study

OBJECTIVES

The large-cell Niti-S stent is useful for multiple stenting in patients with malignant hilar biliary obstruction (MHBO). Recently, a novel uncovered self-expandable metallic stent (USEMS) (a Niti-S large-cell SR slim delivery system) was developed. In this study, we aimed to evaluate the efficacy of this USEMS slim delivery system in MHBO patients.

MATERIALS AND METHODS

Outcomes related to USEMS placement, the clinical course, and the period to recurrent biliary obstruction (RBO) were evaluated in MHBO patients who received multiple USEMSs with the Niti-S large-cell SR slim delivery system.

RESULTS

Twenty-two MHBO patients underwent the placement of multiple USEMSs, including the novel slim-delivery stent. Six patients had a past history of upper gastrointestinal reconstruction (Billroth I: 1, Billroth II: 4, Roux-en-Y: 1). The number of USEMSs placed in each patient was 2-6. Three procedures were reinterventions. The new slim delivery system was placed as the first stent in ten patients and as an additional stent in the remaining patients. Seven patients were drained using only Niti-S large-cell SR slim delivery stents. The technical and clinical success rates were both 100%.

CONCLUSIONS

Placing multiple USEMSs in patients with a past history of abdominal surgery or in reintervention is difficult. Although difficult cases were included in this study, stent-in-stent placement with the novel Niti-S large-cell SR slim delivery system was useful in treating MHBO patients. In addition, this novel stent might be the first choice for MHBO patients.KEY MESSAGESEndoscopic multistenting for MHBO is challenging. In addition, reintervention or multistenting for MHBO patients with a past history of abdominal surgery becomes more difficult.The novel Niti-S large-cell SR slim delivery USEMS is useful as an additional stent because the delivery system is thin and suitable for a 0.025 guidewire. In addition, the novel stent is of the braided type and has a large mesh. Therefore, the novel stent is expected to have strong radial force and can be used as the first SEMS.The Niti-S large-cell SR slim delivery stent is long enough to be used in patients with upper gastrointestinal reconstruction. Although this study included patients with reintervention or a past history of upper gastrointestinal reconstruction, the technical success rate of multiple stenting for MHBO patients was 100%. The slim-delivery stent might overcome several difficulties of endoscopic multistenting.

Endoscopic Reintervention for Recurrence of Malignant Biliary Obstruction: Developing the Best Strategy

Drainage therapy for malignant biliary obstruction (MBO) includes trans-papillary endoscopic retrograde biliary drainage (ERBD), percutaneous transhepatic biliary drainage (PTBD), and trans-gastrointestinal endoscopic ultrasound-guided biliary drainage (EUS-BD). With the development of chemotherapy, many MBO cases end up needing endoscopic reintervention (E-RI) for recurrent biliary obstruction. To achieve a successful E-RI, it is necessary to understand the various findings regarding E-RI in MBO cases reported to date. Therefore, in this review, we focus on E-RI for ERBD of distal MBO, ERBD of hilar MBO, and EUS-BD. To plan an appropriate E-RI strategy for biliary stent occlusion for MBO, the following must be considered on a case-by-case basis: the urgency of the drainage, the cause of the occlusion, the original route of drainage (PTBD/ERBD/EUS-BD), the initial stent used (plastic stent or self-expandable metallic stent), and in the case of self-expandable metallic stents, the type used (fully covered or uncovered). Regardless of the original method of stent placement, if the inflammation caused by obstructive cholangitis is severe and/or the patient is in shock, PTBD should be considered as the first choice. Finally, it is important to keep in mind that in many cases, performing E-RI will be difficult.

Percutaneous stent-in-stent placement with large cell-type stents for malignant hilar biliary obstruction

BACKGROUND

To overcome the technical difficulty of bilateral stent-in-stent placement, large cell-type biliary stents have been developed. However, most of the studies using large cell-type stents were conducted with endoscopic method.

PURPOSE

To evaluate the efficacy and safety of percutaneous stent placement with a stent-in-stent method using large cell-type stents in patients with malignant hilar biliary obstruction.

MATERIAL AND METHODS

From December 2015 and October 2018, 51 patients with malignant hilar biliary obstruction were retrospectively studied. All of the patients underwent bilateral (n=46) or unilateral (n=5) stenting in a T, Y, or X configuration with a stent-in-stent method using large cell-type stents. Technical success, complications, successful internal drainage, stent patency, and patient survival were analyzed.

RESULTS

A total of 118 stents were successfully placed in 51 patients (100.0%). Three patients had minor complications with self-limiting hemobilia. Major complications were not observed in any patient. Successful internal drainage was achieved in 45 patients (88.2%). Clinical follow-up information until death or the end of the study was available for 50 of 51 patients. The median patient survival was 285.5 days (95% confidence interval [CI] 197-374). Stent dysfunction occurred in 16 patients (35.6%) due to tumor ingrowth (n=9) or tumor ingrowth combined with biliary sludge (n=7) among the patients who achieved successful internal drainage. Median stent patency was 179 days (95% CI 104-271).

CONCLUSION

Percutaneous stent-in-stent placement with large cell-type stents is technically feasible and safe, and can be an effective technique in patients with malignant hilar biliary obstruction.

ePTFE-based biomedical devices: An overview of surgical efficiency

Polytetrafluoroethylene (PTFE) is a ubiquitous material used for implants and medical devices in general because of its high biocompatibility and inertness: blood vessel, heart, table jawbone, nose, eyes, or abdominal wall can benefit from its properties in case of disease or injury. Its expanded version, ePTFE is an improved version of PTFE with better mechanical properties, which extends its medical applications. A material as frequently used as ePTFE with these exceptional properties deserves a review of its main uses, developments, and possibility of improvements. In this systematic review, we examined clinical trials related to ePTFE-based medical devices from the literature. Then, we excluded all trials using ePTFE as a control to test other devices. ePTFE-coated stents, hemodialysis and bypass grafts, guided bone and tissue regeneration membranes, hernia and heart repair and other devices are reviewed. The rates of success using these devices and their efficiency compared to other materials used for the same purposes are reported. ePTFE appears to be more or just as efficient compared to them. Some success rates remain low, suggesting the need of improvement ePTFE for medical applications.

Predictors of stent dysfunction in patients with bilateral metal stents for malignant hilar obstruction

Introduction

For unresectable hilar obstruction, restoring and maintaining biliary ductal patency are crucial for improved survival and quality of life. The endoscopic placement of stents is now a mainstay of its treatment, and bilateral stenting is effective for biliary decompression. This study aimed to determine the clinical outcomes of bilateral metal stent placement using large cell-type stents and the clinical predictors of stent dysfunction in patients with malignant hilar obstruction.

Methods

We performed a retrospective analysis of patients who underwent bilateral metal stent placement using two large cell-type stents at two academic teaching hospitals between September 2017 and February 2019. The primary outcome was stent dysfunction. Secondary outcomes included predictors related to stent dysfunction and overall survival.

Results

The study included 87 patients who underwent bilateral metal stent placement for malignant hilar obstruction. Technical success and clinical success were achieved in 80 patients (92.0%) and 83 patients (95.4%), respectively. During the follow-up period (median: 201, range: 18–671 days), stent dysfunction occurred in 42 patients (48.3%), and the median stent patency was 199 days (95% confidence interval [CI]: 181–262). In univariate analysis, age, cholangitis before stent insertion, and subsequent chemotherapy were found to be associated with the cumulative risk of stent dysfunction. In multivariate analysis, cholangitis before stent insertion (hazards ratio [HR]: 2.26, 95% CI: 1.216–4.209, P = 0.010) and subsequent chemotherapy (HR:  0.250, 95% CI: 0.130–0.482, P<0.001) remained as statically significant factors associated with the cumulative risk of stent dysfunction. The median overall survival was 288 days (95% CI: 230–327).

Conclusion

The bilateral placement of large cell-type stents for malignant hilar obstruction was effective with high technical and clinical success rates and acceptable patency. Cholangitis before stent insertion was associated with shorter patency, and subsequent chemotherapy was associated with longer stent patency.

Placement of a newly designed partially covered T- or Y-configured self-expanding metallic stent for hilar biliary obstruction: technical note

PURPOSE

To investigate the technical success, efficacy, and safety of a newly designed partially covered bilateral self-expanding metallic stent (SEMS) in patients with malignant biliary obstruction.

MATERIAL AND METHODS

From May 2016 to November 2017, ten patients with malignant hilar biliary stenosis (bismuth type II-IV) underwent stent placement with the newly designed partially covered T/Y-configured SEMS. Technical success, drainage catheter removal, jaundice remission, early and late complications, stent patency, and overall survival were analyzed.

RESULTS

The stent was successfully deployed in all patients. The total bilirubin level significantly decreased one month after stent placement (P < 0.05). Drainage catheter removal rate was 90%. Two cases (20%) experienced early complications (bile duct hemorrhage and cholangitis) and two cases (20%) experienced late complications (hepatic abscess and cholangitis). During the follow-up (mean 276 days; range 57-503 days) stent occlusion occurred in three patients (30%), and two patents died of hepatic failure. The median stent patency and overall survival were 275 days (95% CI 223.8-326.3 days) and 428.9 days (95% CI 347.9-509.8 days), respectively.

CONCLUSION

The newly designed partially covered T/Y-configured SEMS is technically feasible and clinically effective for biliary trifurcation obstruction.

Single-session multiple stent deployment using moving cell stent without dilating initial stent mesh to treat malignant hilar biliary obstruction (with videos)

BACKGROUND

Malignant hilar biliary obstruction (MHBO) can be treated with bilateral self-expandable metal stents (SEMS) deployed using side-by-side (SBS) or stent-in-stent (SIS) techniques. Moving cell stents (MCS) are a novel type of SEMS. The present study evaluated the technical feasibility of treating MHBO using bilateral novel uncovered SEMS to insert an SIS technique without dilating the mesh of a first stent within a single session.

METHOD

We retrospectively assessed patients who were complicated with obstructive jaundice due to MHBO between August and December 2018. Technical success was defined as the deployment of a bilateral MCS into two or more biliary tracts using SIS technique without a dilation device.

RESULTS

The present study analyzed data from 23 consecutive patients who were complicated with MHBO. Bilateral SIS technique with MCS was deployed in 22 (95.6%) of the 23 patients without dilating the mesh of the first stent. Multiple guidewire insertion failed in one patient with Bismuth-type IV. The median procedural duration was 33.6 min. Time to recurrent biliary obstruction was 230 days. Severe adverse events were not seen in any patients.

CONCLUSION

In conclusion, uncovered moving cell SEMS might facilitate bilateral stent deployment using SIS technique.

Prospective Multicenter Study of the Challenges Inherent in Using Large Cell-Type Stents for Bilateral Stent-in-Stent Placement in Patients with Inoperable Malignant Hilar Biliary Obstruction

Background/Aims

Although endoscopic bilateral stent-in-stent placement is challenging, many recent studies have reported promising outcomes regarding technical success and endoscopic re-intervention. This study aimed to evaluate the technical accessibility of stent-in-stent placement using large cell-type stents in patients with inoperable malignant hilar biliary obstruction.

Methods

Forty-three patients with inoperable malignant hilar biliary obstruction from four academic centers were prospectively enrolled from March 2013 to June 2015.

Results

Bilateral stent-in-stent placement using two large cell-type stents was successfully performed in 88.4% of the patients (38/43). In four of the five cases with technical failure, the delivery sheath of the second stent became caught in the hook-cross-type vertex of the large cell of the first stent, and subsequent attempts to pass a guidewire and stent assembly through the mesh failed. Functional success was achieved in all cases of technical success. Stent occlusion occurred in 63.2% of the patients (24/38), with a median patient survival of 300 days. The median stent patency was 198 days. The stent patency rate was 82.9%, 63.1%, and 32.1% at 3, 6, and 12 months postoperatively, respectively. Endoscopic re-intervention was performed in 14 patients, whereas 10 underwent percutaneous drainage.

Conclusions

Large cell-type stents for endoscopic bilateral stent-in-stent placement had acceptable functional success and stent patency when technically successful. However, the technical difficulty associated with the entanglement of the second stent delivery sheath in the hook-cross-type vertex of the first stent may preclude large cell-type stents from being considered as a dedicated standard tool for stent-in-stent placement.

Clinical Outcomes of Bilateral Stent-in-Stent Placement Using Self-Expandable Metallic Stent for High-Grade Malignant Hilar Biliary Obstruction

PURPOSE

Endoscopic bile duct decompression using bilateral self-expandable metallic stents (SEMSs) deployed via a stent-in-stent (SIS) method is considered a preferred procedure for malignant hilar biliary obstruction (MHBO). However, occlusion thereof occurs frequently. Here, we investigated stent patency duration and risk factors related to stent obstruction with bilateral SIS placement for MHBO at two large centers.

MATERIALS AND METHODS

The present study reviewed data on patients with MHBO who underwent endoscopic biliary drainage using the SIS method. Clinical outcomes, including stent patency duration and patient overall survival, were analyzed. Factors associated with stent patency were evaluated using Cox proportional hazards models.

RESULTS

Seventy patients with MHBO underwent endoscopic biliary drainage using the SIS method. Median age was 68 years old, and median follow-up duration was 140 days (interquartile range, 57-329). The proportion of high-grade MHBOs (Bismuth type IV) was 57.1%. Median stent patency duration with the SIS method was 108 days according to Kaplan-Meier curves. Median patient survival analyzed by the Kaplan-Meier method was 181 days. Multivariate analysis indicated that higher baseline bilirubin (> 6.1 mg/dL) as an independent risk factor related to stent patency (p<0.05).

CONCLUSION

In endoscopic biliary decompression using SEMS placed with the SIS method, obstructive jaundice was a risk factor for stent patency. The SIS method for high-grade MHBO showed short stent patency.

Predictive factors for the failure of endoscopic stent-in-stent self-expandable metallic stent placement to treat malignant hilar biliary obstruction

AIM

To investigate the factors predictive of failure when placing a second biliary self-expandable metallic stents (SEMSs).

METHODS

This study evaluated 65 patients with an unresectable malignant hilar biliary obstruction who were examined in our hospital. Sixty-two of these patients were recruited to the study and divided into two groups: the success group, which consisted of patients in whom a stent-in-stent SEMS had been placed successfully, and the failure group, which consisted of patients in whom the stent-in-stent SEMS had not been placed successfully. We compared the characteristics of the patients, the stricture state of their biliary ducts, and the implemented endoscopic retrograde cholangiopancreatography (ERCP) procedures between the two groups.

RESULTS

The angle between the target biliary duct stricture and the first implanted SEMS was significantly larger in the failure group than in the success group. There were significantly fewer wire or dilation devices (ERCP catheter, dilator, or balloon catheter) passing the first SEMS cell in the failure group than in the success group. The cut-off value of the angle predicting stent-in-stent SEMS placement failure was 49.7 degrees according to the ROC curve (sensitivity 91.7%, specificity 61.2%). Furthermore, the angle was significantly smaller in patients with wire or dilation devices passing the first SEMS cell than in patients without wire or dilation devices passing the first SEMS cell.

CONCLUSION

A large angle was identified as a predictive factor for failure of stent-in-stent SEMS placement.

Study of self-expandable metallic stent placement intraluminal 125I seed strands brachytherapy of malignant biliary obstruction

OBJECTIVE

To evaluate the safety and efficacy of self-expandable metallic stent placement combined with or without intraluminal ¹²⁵I seed strands brachytherapy in patients with malignant biliary obstruction.

METHODS

Participants were randomly assigned to receive treatment with a self-expandable metallic stent (SEMS) placement combined with intraluminal ¹²⁵I seed strands brachytherapy (brachytherapy group) or a SEMS without brachytherapy (control group). The outcomes were measured in terms of technical success, clinical success, stent patency, complications related to the procedure, and patient survival. A P value of less than 0.05 indicated a significant difference. Results There were no significant differences in technical and clinical success between brachytherapy and control group (100 vs. 100%-100 vs. 93.3%). During the median 273.4 ± 154.6 days follow-up time, the median stent patency time in the brachytherapy group was longer than those in the control group (368.0 ± 42.4 vs. 220.0 ± 34.8 days), and the duration of survival in the brachytherapy groups was higher than those in the control group (355.0 ± 71.5 vs. 209.0 ± 17.2 days). There were no significant differences in the complications between the two groups. Conclusions SEMS placement combined with intraluminal ¹²⁵I seed strands brachytherapy are feasible and effective for malignant biliary obstruction, and seems to prolong the stent patency and survival time.

Placement of a Newly Designed Y-Configured Bilateral Self-Expanding Metallic Stent for Hilar Biliary Obstruction: A Pilot Study

BACKGROUND

Whether unilateral or bilateral drainage should be performed for malignant hilar biliary obstruction remains a matter of debate. Although a Y-stent with a central wide-open mesh facilitates bilateral stent placement, it has its own limitations.

AIM

This study aims to evaluate the feasibility and efficacy of a newly designed Y-configured bilateral self-expanding metallic stent (SEMS) for the treatment of hilar biliary obstruction.

METHODS

In this retrospective study, 14 consecutive patients with unresectable malignant hilar biliary obstruction (Bismuth type II or higher), who underwent placement of a newly designed Y-configured bilateral SEMS for hilar biliary obstruction from April 2013 to March 2015, were included into this study. Data on technical success, clinical success, stent patency, complications and patient survival were collected.

RESULTS

Technical and clinical success was 100 and 92.9 %, respectively. Mean serum bilirubin level was significantly decreased 1 month after stent placement (P < 0.01). Furthermore, two patients (14.3 %) had early complications (one patient had severe hemobilia and one patient had cholangitis), and two patients (14.3 %) had late complications (one patient had cholangitis and one patient had cholecystitis). During the mean follow-up period of 298 days (range 89-465 days), six patients (42.9 %) developed stent occlusion caused by tumor ingrowth or overgrowth (n = 5) and sludge (n = 1). Median stent patency and overall survival times were 281 days (95 % CI 175.9-386.1 days) and 381 days (95 % CI 291.4-470.6 days), respectively.

CONCLUSION

The use of the newly designed Y-configured bilateral SEMS is feasible and effective for hilar biliary obstruction using port docking deployment.

Reintervention for stent occlusion after bilateral self-expandable metallic stent placement for malignant hilar biliary obstruction

BACKGROUND AND AIM

Endoscopic reintervention for stent occlusions following bilateral self-expandable metallic stent (SEMS) placement for malignant hilar biliary obstruction (MHBO) is challenging, and time to recurrent biliary obstruction (RBO) of the revisionary stent remains unclear. We aimed to clarify a suitable reintervention method for stent occlusions following bilateral SEMS placement for MHBO.

METHODS

Between 2002 and 2014, 52 consecutive patients with MHBO who underwent endoscopic reintervention for stent occlusion after bilateral SEMS placement were enrolled at two university hospitals and one tertiary care referral center. We retrospectively evaluated the technical and functional success rates of the reinterventions, and the time to RBO of the revisionary stents.

RESULTS

Technical and functional success rates of the reinterventions were 92% (48/52) and 90% (43/48), respectively. Univariate analysis did not determine any significant predictive factors for technical and functional failures. Median time to RBO of the revisionary stents was 68 days. Median time to RBO was significantly longer for revisionary SEMS placement than for plastic stent placement (131 days vs 47 days, respectively; log-rank test, P = 0.005). Revisionary SEMS placement was the only independent factor that was significantly associated with a longer time to RBO of the revisionary stent in the multivariate Cox proportional hazards analysis (hazard ratio 0.37; 95% confidence interval 0.14-0.95; P = 0.039).

CONCLUSION

Revisionary SEMS placement is a suitable endoscopic reintervention method for stent occlusion following bilateral SEMS placement from the perspective of time to RBO of the revisionary stent.

Y-configured metallic stent combined with (125)I seed strands cavity brachytherapy for a patient with type IV Klatskin tumor

We report a case in an inoperable patient with type IV Klatskin tumor treated by the use of a novel, two piece, Y-configured self-expandable metallic stent (SEMS) combined with two ¹²⁵I seed strands via bilateral approach. The placement of the Y-shaped SEMS was successful and resulted in adequate biliary drainage. After 2 months of intraluminal brachytherapy (ILBT), both ¹²⁵I seed strands and temporary drainage catheter were removed after patency of the expanded stents was confirmed by the cholangiogram. This technique was feasible and could be considered for the treatment of patients with Bismuth type IV Klatskin tumors.

Basic Knowledge about Metal Stent Development

Biliary self-expandable metal stents (SEMS), a group of non-vascular stents, have been used in the palliative management of biliary obstruction around the world. However, there are still unmet needs in the clinical application of biliary SEMS. Comprehensive understanding of the SEMS is required to resolve the drawbacks and difficulties of metal stent development. The basic structure of SEMS, including the materials and knitting methods of metal wires, covering materials, and radiopaque markers, are discussed in this review. What we know about the physical and mechanical properties of the SEMS is very important. With an understanding of the basic knowledge of metal stents, hurdles such as stent occlusion, migration, and kinking can be overcome to develop more ideal SEMS.

Air cholangiography in endoscopic bilateral stent-in-stent placement of metallic stents for malignant hilar biliary obstruction

BACKGROUND

Although endoscopic bilateral stent-in-stent (SIS) placement of self-expandable metallic stents (SEMS) is one of the major palliative treatments for unresectable malignant hilar biliary obstruction, post-endoscopic retrograde cholangiopancreatography (ERCP) cholangitis can occur frequently due to inadequate drainage, especially after contrast injection into the biliary tree. The aim of this study is to evaluate the efficacy and safety of air cholangiography-assisted stenting.

METHODS

This study included 47 patients with malignant hilar biliary obstruction who underwent endoscopic bilateral SEMS placement using the SIS technique. They were divided into two groups, air (n = 23) or iodine contrast (n = 24) cholangiography. We retrospectively compared comprehensive clinical and laboratory data of both groups.

RESULTS

There were no significant differences found between the two groups with respect to technical success (87% versus 87.5%, air versus contrast group, respectively), functional success (95% versus 95.2%), 30-day mortality (8.3% versus 8.7%) and stent patency. Post-ERCP adverse events occurred in 5 (21.7%) of the patients in the air group and 8 (33.3%) of the patients in the contrast group. Among these, the rate of cholangitis was significantly lower in the air group (4.8% versus 29.2%, p = 0.048). In multivariate analysis, air cholangiography, technical success and a shorter procedure time were significantly associated with a lower incidence of post-ERCP cholangitis.

CONCLUSIONS

Air cholangiography-assisted stenting can be a safe and effective method for endoscopic bilateral SIS placement of SEMS in patients with malignant hilar biliary obstruction.