A multi-center, single arm, prospective study of the WallFlex biliary partially covered stent for the palliative treatment of malignant bile duct obstruction.

Common treatment of patients with malignant biliary obstruction is endoscopic
stent placement. Patient with metal stents typically undergo subsequent
procedures only when a complication arises, whereas patients with plastic
stents typically require subsequent procedures for stent exchange every 3 or 4
months. Studies have shown that although metal stents are initially more
expensive than plastic stents, metal stents are associated with lower overall
costs for patients surviving longer than 3 months.
Tumor ingrowth through the struts of the stent and overgrowth over the ends of
the stent have proved to be limitations of metal stent devices. Covered metal
stents were designed to prolong patency by preventing tumor ingrowth. An
increased rate of stent migration is a potential issue in the use of covered
stents, as the smooth surface reduces friction between teh stent and the
tissue.

The WallFlex biliary partially-covered stent is being evaluated as a treatment
for biilary strictures caused by malignant neoplasms and has the following
features and anticipated benefits:

* Partial covering: decreased potential for tumor or tissue in-growth compared
to bare metal stents
* Looped wire ends: decreased potential for tissue damage from sharp wires at
stent ends
* Flared ends: decreased potential for migration
* Retrieval loop: allows the stent to be removed during the intital placement
procedure

The overall objective of this study is to assess the functionality of the
WallFlex Biliary Partially-covered stent as a palliative treatment for
malignant bile duct obstruction.

A multi-center, single arm, prospective study.

Patients will be treated with a WallFlex Biliary Partially-covered stent.

The WallFlex Biliary Partially-covered Stent is not expected to present
increased risk to study patients compared to previously approved and marketed
metal biliary stents. The primary risks associated with metal biliary stents
include: pain, bleeding, fever, nausea, vomiting, infection, inflammation,
recurrent obstructive jaundice, stent occlusion, tumor overgrowth around ends
of stent, tumor ingrowth through the stent, mucosal hyperplasia, cholangitis,
cholecystitis, pancreatitis, bile duct ulceration, perforation of duodenum or
bile duct, stent migration, stent misplacement, death (other than that due to
normal disease progression)

The study follow-up visits may be conducted by phone, however, patients will be
required to have their blood drawn for liver function testing at 1 Month.
Study visits will be Screening/Baseline, Procedure, 1 Week, 2 Weeks, 1 Month, 3
Months, and 6 Months