A prospective randomized study for efficacy of an uncovered double bare metal stent compared to a single bare metal stent in malignant biliary obstruction

Characteristics of four commonly used self-expanding biliary stents: an in vitro study

BACKGROUND

Knowledge of the characteristics of self-expanding metal stents (SEMSs) is essential during selection process to ensure the best therapeutic outcomes for patients with malignant biliary obstruction. The aim of this study was to evaluate the characteristics of four commonly used SEMSs.

METHODS

This in vitro study analyzed the radial force (RF), crush resistance (CR), axial force (AF), conformability, surface quality, foreshortening, and radiopacity of the following SEMSs: uncovered Wallflex™, EGIS single bare, Zilver 635®, and E-Luminexx™. Two samples of each SEMS type were included in this study, all having identical specifications with a diameter of 10 mm and a length of 6 cm. One sample from each type was analyzed for surface quality, followed by CR, conformability, and foreshortening. The other sample was analyzed for radiopacity, followed by RF and AF.

RESULTS

The uncovered Wallflex™ exhibited low RF, high CR, high AF, good conformability, poor surface quality, high foreshortening, and good radiopacity. The EGIS single bare demonstrated high RF, high CR, low AF, moderate conformability, good surface quality, high foreshortening, and poor radiopacity. The Zilver 635® displayed moderate RF, low CR, low AF, moderate conformability, moderate surface quality, no foreshortening, and good radiopacity. The E-Luminexx™ showed high RF, moderate CR, high AF, poor conformability, poor surface quality, no foreshortening, and good radiopacity.

CONCLUSIONS

There was considerable variation in the characteristics among the four evaluated SEMSs. These characteristics should be carefully considered during selection to ensure optimal therapeutic outcomes for patients.

RELEVANCE STATEMENT

The selection of self-expanding metal stents for treating malignant biliary obstruction requires careful consideration of various characteristics, including their radial force, crush resistance, axial force, conformability, surface quality, foreshortening, and radiopacity.

KEY POINTS

• The characteristics of self-expanding metal stents (SEMSs) can vary considerably. • Specific situations may warrant the use of SEMSs with particular characteristics over others. • Characteristics of SEMSs must be considered during selection for optimal outcomes.

Double bare metal stent deployment combined with intraductal radiofrequency ablation for malignant distal biliary obstruction: a prospective pilot study

Although uncovered self-expandable metal stents (SEMSs) possess certain advantages such as averting cystic duct obstruction and stent migration, they are susceptible to ingrowth occlusion. The combination of the double bare stent (DBS) and endobiliary radiofrequency ablation (RFA) may reduce ingrowth. Hence, this study aimed to examine the utility of this method for the treatment of unresectable malignant distal biliary obstruction (MDBO). This prospective, single-center, pilot study enrolled 51 patients who met the eligibility criteria between February 2020 and January 2022. The study outcomes included technical success, clinical success, recurrent biliary obstruction (RBO), and other adverse events (AE) besides RBO associated with DBS placement with RFA for MDBO. The technical success rate was 98.0% (50/51). Clinical success was achieved in all patients in whom technical success was achieved. The rates of early and late AEs were 5.9% (3/51) and 8.0% (4/50), respectively. The incidence rate of RBO was 38.0% (19/50). Sludge occlusion, ingrowth occlusion, and overgrowth occlusion occurred in 26.0% (13/50), 8.0% (4/50), and 2.0% (1/50) of patients, respectively (the main cause of RBO was undeterminable in 1 patient). The median time to RBO was 241 days. DBS with RFA showed good technical feasibility, good long-term outcomes, acceptable AE rates, and most importantly, a low ingrowth occlusion rate when employed for the treatment of MDBO.

Covered versus uncovered double bare self-expandable metal stent for palliation of unresectable extrahepatic malignant biliary obstruction: a randomized controlled multicenter trial

BACKGROUND AND AIMS

In a recent randomized controlled trial, a double bare metal stent (DBS) showed better stent patency than single-layer metal stents. However, clear evidence comparing the efficacy of uncovered (UCDBS) and partially covered (PCDBS) DBSs for distal malignant biliary obstruction (MBO) is lacking. Therefore, we compared the clinical outcomes including stent patency of UCDBSs versus PCDBSs.

METHODS

A multicenter, randomized study was performed in patients with distal MBO. The primary endpoint was stent patency. Secondary endpoints were the proportion of patients with patent stents at 6 months, risk factors for stent dysfunction, overall survival, technical and clinical success rates of stent placement, and other adverse events (AEs).

RESULTS

Among 258 included patients, 130 were randomly assigned to the PCDBS group and 128 to the UCDBS group. The mean duration of stent patency of the PCDBS (421.2 days; 95% confidence interval [CI], 346.7-495.7) was longer than that of the UCDBS (377.4 days; 95% CI, 299.7-455.0), although total stent dysfunction and stent dysfunction within 6 months were not different between groups. Multivariate analysis indicated that chemotherapy after stent placement was a significant factor for overall survival (hazard ratio, .570; 95% CI, .408-.796) and had a marginal impact on stent patency (hazard ratio, 1.569; 95% CI, .923-2.667). There were no remarkable differences in AEs, including pancreatitis, cholecystitis, and stent migration, between the 2 groups.

CONCLUSIONS

The use of PCDBSs compared with UCDBSs in patients with distal MBO has unclear benefits regarding stent patency and overall survival, although PCDBSs have a lower rate of tumor ingrowth. (Clinical trial registration number: NCT02937246.).

Percutaneous transpapillary biliary stent placement for distal malignant biliary obstruction: Outcomes and survival analysis

BACKGROUND/AIMS

For distal malignant biliary obstruction (MBO), a percutaneous metal stent is usually inserted by the transpapillary method. However, stent-related complications and recurrent biliary obstruction following transpapillary stent placement are concerns, and survival analysis of patients with distal MBO has rarely been done.

MATERIALS AND METHODS

From January 2012 to March 2016, 104 patients underwent transpapillary uncovered metal stent placement for distal MBO at our institution. Clinical success, complications, recurrent biliary obstruction rates, and predictors of survival were analyzed.

RESULTS

Of the total 104 patients, clinical success after stent insertion was achieved in 93 patients (90.3%). Major complications were observed in 24 patients (23.1%), which were as follows: cholangitis in 19 patients; pancreatitis in four patients; and biloma in one patient. Recurrent biliary occlusion was observed in 28 patients (26.9%). The median overall survival period was 162 days. The 3-, 6-, and 12-month overall survival rates after stent insertion were 64.4%, 41.3%, and 10.6%, respectively. Results of multivariate analysis indicated that metastatic carcinoma compared with ampullary carcinoma (HR=3.82; 95% CI, 1.30-11.24; p=0.015) and longer biliary stricture (HR=1.04; 95% CI, 1.02-1.06; p<0.001) were independent risk factors for worse survival after metal stent insertion.

CONCLUSION

Transpapillary stent placement was found to be effective with acceptable complication rates for treating distal MBO. Primary tumor and length of biliary stricture were found to be statistically significant independent prognostic factors for survival.

Differences in efficacy of uncovered self-expandable metal stent in relation to placement in the management of malignant distal biliary obstruction

BACKGROUND/AIMS

Metal stent insertion is a common palliative treatment for distal malignant biliary obstruction (MBO) but whether placement across the sphincter of Oddi (SO) causes more complications or shorter survival is in question. The aim of this study was to compare the clinical outcomes of percutaneous uncovered self-expandable metal stent placement above and across the SO in patients with distal MBO.

PATIENTS AND METHODS

We retrospectively studied 59 patients who underwent uncovered metal stent placement for distal MBO between January 2012 and March 2016. Stents were placed above the SO for 22 subjects (group A) and across the SO for 37 subjects (group B). Early cholangitis, stent occlusion, and overall survival time were compared between the two groups.

RESULTS

Clinical success was 90.9 and 86.5% for groups A and B, respectively. Early cholangitis occurred in 2 patients (9.1%) in group A and in 6 patients (16.2%) in group B (P = 0.645). Median stent patency and median survival time was 105 and 140 days for group A, 120 and 160 days for group B, respectively. The stent occlusion (31.8% in group A and 21.6% in group B, P = 0.454) and the cumulative stent patency times (P = 0.886) did not differ between the two groups. There was no significant difference in cumulative patient survival between the two groups (P = 0.810).

CONCLUSION

Uncovered metal stent placement across the SO did not significantly affect early cholangitis, stent patency, or patient survival.

Bare-metal stents across the Vater's ampulla is a safe method for patients with lower bile duct obstruction

This study explored the effect of the implant position of stents across the Vater's ampulla on treatment outcomes in patients with lower bile duct obstruction.In the retrospective study, 41 patients with malignant obstruction of the lower bile duct and obstructive jaundice received percutaneous transhepatic biliary placement of bare-metal stents. Basic demographic data on patients, such as sex, age, and primary diseases, and follow-up data, including postoperative complications and jaundice-free survival, were recorded. The follow-up data on patients with an involved ampulla, patients with an uninvolved ampulla, patients with a stent across the ampulla, and patients with a stent at a site other than the ampulla were compared. Furthermore, prognostic factors for jaundice- free survival were investigated using Cox proportional hazards regression analysis.Among the 41 patients, 38 patients experienced subsiding of jaundice, whereas 3 cases had unsuccessful stent patency. Whether or not the ampulla was involved did not influence the incidence rates of postoperative complications and the jaundice-free survival time. Notably, when stents were placed across the ampulla, the jaundice-free survival time was significantly longer than when stents were placed at sites other than across the ampulla (P < .05). Furthermore, placement of the stent across the ampulla or at other sites was an independent prognostic factor (hazard ratio = 0.154, 95% confidence interval 0.042-0.560, P = .005) for jaundice-free survival of patients.The current study revealed that the implant position of a stent across the ampulla resulted in maintenance of stent patency and prolongation of the jaundice-free survival time.