Comparative performance of uncoated, self-expanding metal biliary stents of different designs in 2 diameters: final results of an international multicenter, randomized, controlled trial

Received 30 July 2008; accepted 5 November 2008. published online 01 June 2009.

Refers to article:

CME Activity: Continuing Medical Education Exam: September 2009
Raquel E. Davila, Jeffrey H. Lee, William Ross, Shou-Jiang Tang, G.S. Raju, George Triadafilopoulos
Gastrointestinal Endoscopy
September 2009 (Vol. 70, Issue 3, Pages 537-537.e6)
Full-Text PDF (102 KB)

Background

The Wallstent has remained the industry standard for biliary self-expanding metal stents (SEMSs). Recently, stents of differing designs, compositions, and diameters have been developed.

Objective

To compare the new nitinol 6-mm and 10-mm Zilver stents with the 10-mm stainless steel Wallstent and determine the mechanism of obstruction.

Design

Randomized, prospective, controlled study.

Setting

Nine centers experienced in SEMS placement during ERCP.

Patients

A total of 241 patients presenting between September 2003 and December 2005 with unresectable malignant biliary strictures at least 2 cm distal to the bifurcation.

Main Outcome Measurement

Stent occlusions requiring reintervention and death.

Results

At interim analysis, a significant increase in occlusions was noted in the 6-mm Zilver group at the P = .04 level, resulting in arm closure but continued follow-up. Final study arms were 64, 88, and 89 patients receiving a 6-mm Zilver, 10-mm Zilver, and 10-mm Wallstent, respectively. Stent occlusions occurred in 25 (39.1%) of the patients in the 6-mm Zilver arm, 21 (23.9%) of the patients in the 10-mm Zilver arm, and 19 (21.4%) of the patients in the 10-mm Wallstent arm (P = .02). The mean number of days of stent patency were 142.9, 185.8, and 186.7, respectively (P = .057). No differences were noted in secondary endpoints, and the study was ended at the 95% censored study endpoints. Biopsy specimens of ingrowth occlusive tissue revealed that 56% were caused by benign epithelial hyperplasia.

Conclusions

SEMS occlusions were much more frequent with a 6-mm diameter SEMS and equivalent in the two 10-mm arms despite major differences in stent design, material, and expansion, suggesting that diameter is the critical feature. Malignant tumor ingrowth produced only a minority of the documented occlusions.

Portland, Maine, Springfield, Massachusetts, Denver, Colorado, Chicago, Illinois, Charleston, South Carolina, Pittsburgh, Pennsylvania, Indianapolis, Indiana, USA, Toronto, Ontario, Canada, Düsseldorf, Germany

Abbreviation: FDA, U.S. Food and Drug Administration, SEMS, self-expanding metal stent

Current affiliations: Maine Medical Center (B.J.L., D.A.H., M.K.S.), Portland, Maine, Baystate Medical Center (D.J.S.), Springfield, Massachusetts, St. Michael's Hospital (P.P.K., G.R.M.), Toronto, Ontario, Canada, University of Colorado Health Sciences Center (Y.K.C.), Denver, Colorado, Northwestern Memorial Hospital (W.G.P.), Chicago, Illinois, Medical University of South Carolina (R.H.H., P.B.C.), Charleston, South Carolina, University of Pittsburgh Medical Center (A.A.S., J.A.), Pittsburgh, Pennsylvania, Indiana University School of Medicine (G.A.L., S.S.), Indianapolis, Indiana, USA, Evangelisches Krankenhaus (H.N., B.M.S.), Düsseldorf, Germany

Reprint requests: Douglas A. Howell, MD, 1200 Congress Street, Suite #300, Portland, ME 04102-2129.

DISCLOSURE: The following authors disclosed financial relationships relevant to this publication: D. A. Howell: Cook Medical: royalty on unrelated product, grant, research support, speaking and teaching; Boston Scientific: grant/research support. D. J. Desilets: Cook Medical: grant/research support; royalty on patent held/filed. R. J. Shah: Boston Scientific: speaking/teaching; Wilson–Cook Medical: grant/research support; Boston Scientific: grant/research support, consulting fee. R. H. Hawes: Boston Scientific: consulting fee. P. B. Cotton: Cook: royalty on patent held/filed; Boston Scientific: grant/research support. A. A. Slivka: Boston Scientific: consulting fee, speaking/teaching; Wilson–Cook Medical: consulting fee, speaking/teaching. S. Sherman: Boston Scientific: consulting fee, speaking/teaching; Cook: consulting fee, speaking/teaching. This study was supported with institutional grants to each center from Cook Medical. All other authors disclosed no financial relationships relevant to this publication.

See CME section; p. 537.

Presented at: Digestive Disease Week, May 2008, San Diego, California (Gastrointest Endosc 2009;69:A93).

If you would like to chat with an author of this article, you may contact him at howeld@mmc.org.

PII: S0016-5107(08)02900-3

doi:10.1016/j.gie.2008.11.018

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