Covered self-expandable metal stents for benign biliary strictures: a prospective mulitcenter trial

Benign biliary strictures occur most frequently after surgical procedures,
chronic pancreatitis or iatrogenic ampullary stenoses. Traditionally, surgery
has been the treatment of choice. A less invasive alternative is endoscopic or
percutaneous dilatation with plastic stent placement. The major drawbacks of
plastic stents are the need for multiple procedures to avoid cholangitis caused
by stent clogging and to dilate in a stepwise fashion.
As a consequence of their larger diameter, uncovered self expandable metal
stents (SEMS) have been introduced in effort to maintain duct patency for a
longer period than with plastic stents, which will result in fewer procedures.
Uncovered SEMS have been shown to be effective, but long term stent patency is
limited due to tissue ingrowth through the mesh in uncovered stents.
Furthermore, surgical management of patients with SEMS is difficult, as these
devices can hardly be removed due to embedding into the biliary wall. These
disadvantages of uncovered SEMS have led to the development of covered SEMS,
with the potential benefit that these stents can be removed. In addition,
covered stents, because of their diameter, may serve as a dilator. This could
avoid stepwise (every 3 months for one year) dilatation,as is done with plastic
stents, unnecessary and eliminates the necessity of multiple procedures.
Limitate prospective studies on the use of covered SEMS in patients with benign
CBD obstruction have been performed.

The aim of this study is to determine safety, patency of placement and long
term symptom-free outcome of a covered self expandable metal stent in patients
with a benign CBD stricture.

A prospective multicenter study in 25 Dutch centres.

After informed consent, all patients included in this study will be given a
covered SEMS following preceding dilation during ERCP.

During ERCP a covered SEMS will be placed. Prior to stent placement the biliary
stricture will be dilated to a diameter of 10 Fr, if indicated to advance the
SEMS introduction device.Dilation and stent placement will be performed during
ERCP. One week after stent placement serum aspartate aminotransferase (ASAT),
alanine aminotransferase (ALAT), alkaline phosphatise (AP), gamma-glutamyl
transferase (*-GT) and bilirubin will be measured. After 3 months, ERCP will be
performed to remove the covered SEMS and another blood sample will be collected
to measure ASAT, ALAT, AP, *-GT and bilirubin. One week, 3, 6, and 9 months
after stent removal another blood sample will be collected to measure the same
parameters. In case of signs of symptoms of CBD obstruction, an ERCP will be
performed and a plastic stent will be placed.