Trial Information

A Randomized Trial Comparing a Winged Perimeter Stent and Traditional Polyethylene Plastic Stent in the Management of Malignant Distal Biliary Strictures

Biliary obstruction usually presents with jaundice, pruritis, cholangitis, and steatorrhoea.
Strictures which are a common cause of biliary obstruction, may be secondary to benign or
malignant conditions. Common benign conditions include chronic pancreatitis, primary
sclerosing cholangitis, autoimmune pancreatitis, prior surgery and recurrent pyogenic
cholangitis. Cholangiocarcinomas, ampullary and pancreatic tumours are more common causes
of malignant biliary obstruction.

The principles of managing biliary strictures are to determine the underlying cause of the
stricture, whilst achieving drainage of the biliary tree, initially with the placement of a
plastic stent via an endoscopic retrograde cholangiopancreatography (ERCP). Strictures are
sampled using biliary brush cytology and/or biliary biopsy to assess for underlying
malignancy. Malignant strictures are usually staged for resectability with computed
tomography (CT), magnetic resonance cholangiopancreatography (MRCP) and/or endoscopic
ultrasound (EUS).

The Viaduct stent (GI Supply, Camp Hill, Pennsylvania, USA) is a unique stent design and has
a winged perimeter, which channels flow of bile around the stent, rather than through a
central lumen. Theoretically this may enhance flow and biliary drainage, and prevent
obstruction. Both polyethylene and Viaduct plastic stents are approved for use by Health
Canada for benign and malignant biliary conditions. It is not known whether one stent is
superior to the other in maintaining symptomatic relief from bile duct strictures as there
have been no studies to date comparing the two stents.

There is limited published data on the Viaduct stent. A pilot study of the winged stent
design was published in 2006. Five patients had winged stents inserted and followed for 2
weeks. The were no problems with stent insertion and symptoms of obstruction and jaundice
improved over this time. One study published in abstract form retrospectively compared 34
Viaduct stents matched with 240 "conventional" stents over a five year period. There was no
statistical difference with stent dysfunction, and a trend towards patency with the Viaduct
stent.

The primary aim of this study is to compare the stent patency time in the Viaduct and
polyethylene stent groups in subjects with malignant bile duct strictures. The secondary
aims are to determine the etiology of stent failure in the two treatment groups, to identify
and compare device-related adverse events in the two treatment groups, to identify other
patient factors associated with stent failure, and to compare survival between the Viaduct
and polyethylene stent groups.