Expandable biliary stents: more questions than answers

Cost Efficacy of Metal Stents for Palliation of Extrahepatic Bile Duct Obstruction in a Randomized Controlled Trial

BACKGROUND & AIMS

Endoscopic stents are placed for palliation of extrahepatic bile duct obstruction. Although self-expandable metal stents (SEMS) remain patent longer than plastic stents, they are more expensive. We aimed to evaluate which type of stent (plastic, uncovered SEMS [uSEMS], or partially covered SEMS [pcSEMS]) is the most effective and we assessed costs.

METHODS

We performed a multicenter randomized trial in 219 patients at 18 hospitals in The Netherlands from February 2008 through February 2013. Patients were assigned randomly for placement of a plastic stent (n = 73), uSEMS (n = 75), or pcSEMS (n = 71) during endoscopic retrograde cholangiopancreatography. Patients were followed up for up to 1 year. Researchers were not blinded to groups. The main study end points included functional stent time and costs.

RESULTS

The mean functional stent times were 172 days for plastic stents, 288 days for uSEMS, and 299 days for pcSEMS (P < .005 for uSEMS and pcSEMS vs plastic). The initial placement of plastic stents (€1042 or $1106) cost significantly less than placement of SEMS (€1973 or $2094) (P = .001). However, the total cost per patient at the end of the follow-up period did not differ significantly between plastic stents (€7320 or $7770) and SEMS (€6932 or $7356) (P = .61). Furthermore, in patients with short survival times (≤3 mo) or metastatic disease, the total cost per patient did not differ between plastic stents and SEMS. No differences in costs were found between pcSEMS and uSEMS.

CONCLUSIONS

Although placement of SEMS (uncovered or partially covered) for palliation of extrahepatic bile duct obstruction initially is more expensive than placement of plastic stents, SEMS have longer functional time. The total costs after 1 year do not differ significantly with stent type. Dutch Clinical Trial Registration no: NTR1361.

A comparison of the Niti-D biliary uncovered stent and the uncovered Wallstent in malignant biliary obstruction

BACKGROUND

The conformability of uncovered self-expandable metal stents (SEMSs) plays an important role in maintaining stent patency. However, whether increased conformability can prolong the duration of SEMS patency remains to be proved.

OBJECTIVE

The aim of this study was to examine the efficacy and complication rates of the Niti-D biliary uncovered metal stent (NDS), which is more conformable than the uncovered Wallstent.

DESIGN

Nonrandomized, retrospective study.

SETTING

Tertiary-care academic medical center.

PATIENTS

From March 2005 to July 2007, 101 patients received an NDS (41 cases) or a Wallstent (60 cases) for malignant biliary obstruction.

INTERVENTIONS

SEMS placement.

RESULTS

Stent occlusion occurred in 11 patients (26.8%) with the NDS and 17 patients (28.3%) with the Wallstent. The median duration of stent patency tended to be longer for the NDS group (153 days) than for the Wallstent group (124 days); however, the difference was not statistically significant (P = .204). The median duration of overall survival of patients was 160 days for the NDS and 148 days for the Wallstent. The subgroup analysis showed that 27 patients had hilar obstruction (NDS 13, Wallstent 14). The median duration of stent patency was 249 days for the NDS group and 76 days for the Wallstent group; this difference was statistically significant (P = .006). The complications included pancreatitis in 3 NDS cases and 5 Wallstent cases.

LIMITATION

The absence of prospective randomized recruitment.

CONCLUSION

The results of this study showed no significant differences between the NDS and the Wallstent for the palliative endoscopic management of malignant biliary obstruction. There were no significant differences in patency, complication rates, and patient survival between the more conformable NDS and the conventional Wallstent. However, the NDS, which has good conformability, may be preferred for hilar obstruction.

Newly designed stent for endoscopic bilateral stent-in-stent placement of metallic stents in patients with malignant hilar biliary strictures: multicenter prospective feasibility study (with videos)

BACKGROUND

Endoscopic management of malignant hilar biliary strictures is difficult even for an experienced endoscopist. Moreover, endoscopic placement of bilateral metal stents is considered very difficult and complicated.

OBJECTIVE

We explored the feasibility and efficacy of the placement of a newly designed metal stent for an endoscopic bilateral stent-in-stent procedure for the management of malignant hilar biliary strictures.

DESIGN

Multicenter prospective feasibility study.

SETTING

Five academic tertiary referral centers.

PATIENTS

Thirty-five patients with malignant hilar biliary strictures of Bismuth type II or higher were enrolled.

INTERVENTIONS

Bilateral stent placement by an endoscopic stent-in-stent procedure.

MAIN OUTCOME MEASUREMENTS

Technical success, functional success, early and late complications, stent patency.

RESULTS

The overall technical success rate of the newly designed metal stent was 94.3% (33/35). The success rate of the stent-in-stent procedure in a single session was 82% (27/33) per protocol and 77% (27/35) as intent to treat. In cases in which the initial stent-in-stent procedure failed, patients underwent the endoscopic stent-in-stent procedure for contralateral stent placement at 2 days (6%, 2/33) or 4 days (12%, 4/33) after the initial stent placement. There was no percutaneous insertion of a contralateral stent in these patients. There was no stent-related early or late complication in any enrolled patient. Functional success was 100% (33/33). Reintervention because of stent malfunction was 6% (2/33). These 2 patients showed sludge formation in the stent. During follow-up, there was no stent tumor ingrowth or overgrowth in the placed stent in any enrolled patient. According to the Kaplan-Meier analysis, median survival and stent patency were 180 days and 150 days, respectively.

LIMITATIONS

An uncontrolled feasibility study with a small patient population and a limited follow-up period.

CONCLUSION

The newly designed metal stent for the endoscopic bilateral stent-in-stent procedure may be feasible and effective for malignant hilar biliary strictures.

Comparison of Wallstent and Ultraflex stents for palliation of malignant left-sided colon obstruction: a retrospective, case-matched analysis

BACKGROUND

Self-expandable metal stents (SEMSs) are accepted palliation for malignant colon obstruction. Outcomes of different stent types is unknown.

OBJECTIVE

Our purpose was to compare outcomes after palliative placement of the Enteral Wallstent (EW) and the Precision Colonic Ultraflex (PCU) stent.

DESIGN

Retrospective study of all SEMS placement during a 7-year period.

SETTING

Tertiary care academic medical center.

PATIENTS

Malignant left-sided colon obstruction in which through-the-scope (TTS) or non-TTS stent placement was possible.

MAIN OUTCOME MEASUREMENTS

Technical and clinical success rates, stent-related complications, reintervention.

RESULTS

Demographics, degree, site, and cause of obstruction were comparable. Technical difficulties were more frequent with EW than PCU (16% vs 9%, P not significant), insufficient stent expansion and stent misplacement being most common. Relief of obstruction occurred in all patients when placement was technically successful. Mean follow-up was 93 days (range 7-691 days). Early (<7 days) stent occlusion (6% vs 0%, P not significant) and migration (4% vs 0%, P not significant) occurred more frequently in the EW group. Self-limited hematochezia was more common with PCU (20% vs 2%, P = .002). Delayed complications (perforation, stent occlusion, migration, and erosion) occurred significantly more often in the EW group (38% vs 20%). Reintervention was needed more frequently for EW, endoscopic (40% vs 17%, P = .01) and operative (46% vs 26%, P = .03).

CONCLUSIONS

Enteral Wallstents and Precision Ultraflex Colonic stents adequately relieve colonic obstruction. Stent dysfunction, stent-related complications, and need for reintervention are higher after EW placement. Precision Colonic Ultraflex stents appear better suited for palliation of left-sided malignant colon obstruction.

A comparison of covered and uncovered Wallstents for the management of distal malignant biliary obstruction

BACKGROUND

The efficacy and complications of covered self-expandable metal stents (SEMS) remain controversial.

OBJECTIVE

We conducted this study to compare the efficacies and complication rates of covered and uncovered SEMS in malignant biliary obstruction.

DESIGN

Data on patients who underwent endoscopic retrograde biliary drainage with covered or uncovered Wallstents for the palliation of unresectable distal malignant biliary obstruction were collected. Stent patency, complications, and causes of stent occlusion were analyzed.

SETTING

We collected the data retrospectively.

PATIENTS

A total of 77 patients received Wallstents for unresectable distal malignant biliary obstruction.

INTERVENTIONS

Endoscopic sphincterotomy was performed, and a Wallstent was deployed after guidewire passage. Polyurethane-covered Wallstents were used in 36 patients and uncovered Wallstents in 41 patients.

RESULTS

Stent migration occurred in 3 of the covered Wallstent group and in 1 of the uncovered Wallstent group. Cholecystitis occurred in 1 of the covered Wallstent group but in none of the uncovered Wallstent group. Stent occlusion occurred after a mean of 398 days in the covered group and after 319 days in the uncovered Wallstent group (P > .05). Stent patency rates were 83%, 78%, 67%, and 54% at 100, 200, 300, and 400 days, respectively, in covered group and 83%, 66%, 54%, and 36% in the uncovered group, which was not significantly different.

LIMITATIONS

This study is not a prospective randomized study and sample size is not large.

CONCLUSIONS

Covered Wallstents are safe with acceptable complication rates. However, we found no significant difference between the stent patencies of covered and uncovered Wallstents.

Plastic or metal stents for malignant stricture of the common bile duct? Results of a randomized prospective study

BACKGROUND

The systematic use of metal stents to treat biliary obstruction is restricted by high cost compared with plastic stents. The aims of this study were to compare cost and efficacy of plastic stents and metal stents in the treatment of patients with malignant common bile duct strictures and to define factors that predict survival of these patients.

METHODS

One hundred eighteen patients (mean age 75 years) with malignant strictures of the common bile duct were randomized to placement of a plastic stent or metal stent. Comparisons were made with the Mann-Whitney or chi-square test as indicated; survival rates were compared with a Cox proportional hazards model.

RESULTS

There was no significant difference in survival between the two groups. Time to first obstruction was longer for patients in the metal stent group (metal stent, median not reached vs. plastic stent, 5 months; p = 0.007). The number of additional days of hospitalization, days of antibiotic therapy, and the numbers of ERCPs and transabdominal US procedures was significantly higher in the plastic stent group. After multivariate analysis, only the presence of liver metastases was independently related to survival (p < 0.0005; OR = 2.25). This variable defined a group with a shorter survival. Median survival of patients with hepatic metastasis at diagnosis was 2.7 months compared with 5.3 months for patients without liver metastasis; in the latter group, the overall cost associated with metal stents was lower than for plastic stents.

CONCLUSIONS

Metal stent placement is the most effective treatment of inoperable malignant common bile duct stricture. Placement of a metal stent is cost effective in patients without hepatic metastases, whereas a plastic stent should be placed in patients with spread of the tumor to the liver.