Trial Information

Prospective Evaluation of Luminal Patency of a Prototype Large Plastic Biliary Stent in the Palliation of Malignant Distal Biliary Strictures.

Malignant obstruction of the extra-hepatic bile duct often leads to jaundice and pruritus
and occasionally results in cholangitis and bacteremia. Pancreatic cancer accounts for a
large proportion of patients presenting with malignant extra-hepatic biliary obstruction.
Most pancreatic cancers are unresectable at presentation, and palliation, including biliary
decompression, is often a goal of therapy. Over the last decade, biliary decompression with
endoscopically-placed stents during endoscopic retrograde cholangiopancreatography (ERCP)
has largely replaced surgical bilioenteric diversion. Biliary decompression via endoscopic
stenting alleviates cholestatic symptoms and improves quality of life. When compared to
surgery, endoscopically placed plastic stents result in decreased morbidity and a trend
towards decreased 30 day mortality. However, surgery is associated with a lower risk of
recurrent biliary obstruction.

Stent diameter is an important factor in determining duration of biliary luminal patency.
All plastic biliary stents will ultimately occlude due to deposition of bacterial biofilm.
The original plastic biliary stents were 7 French (Fr) in diameter, with a patency rate of
about 4 weeks. With increases in the size of the working channel of duodenoscopes, the
limiting factor in what diameter stent can be deployed, 10 Fr stents were developed, with
patency rates of approximately 15 weeks (3-4 months). Until recently, the largest stent that
could be deployed with the current endoscopic technology using a conventional duodenoscope
of acceptable outer diameter was 11.5 Fr; the limited available data suggest that these
stents do not offer more prolonged luminal patency interval compared to 10 Fr stents.

In the early 1990s, self-expandable metal stents (SEMS) became available for use in
palliation of malignant biliary obstruction. Once deployed, SEMS achieve larger diameters
than plastic stents, which results in a longer median patency interval of approximately six
to eight months.[3, 6, 9-12] Although effective, metal stents are eight to ten times more
costly than plastic stents.

Recently, a large working channel duodenoscope with an acceptable outer diameter has been
developed. This prototype duodenoscope allows passage of larger stents, which the
investigators have successfully placed in select cases using this prototype. This
duodenoscope, manufactured by Olympus Medical Systems Corp., is FDA approved.

The investigators hypothesize that, with the substantially increased luminal diameter,
larger plastic stents will provide more prolonged relief of obstructive jaundice in patients
with malignant distal common bile duct strictures. If this proves to be true, larger
plastic stents may constitute a cost-effective alternative to SEMS, especially in health
care systems that cannot afford SEMS.