Biosafety of a novel covered self-expandable metal stent coated with poly(2-methoxyethyl acrylate) in vivo.

Covered self-expandable metal stents (CSEMS) are often used for palliative endoscopic biliary drainage; however, the unobstructed period is limited because of sludge occlusion. The present study aimed to evaluate the biosafety of a novel poly(2-methoxyethyl acrylate)-coated CSEMS (PMEA-CSEMS) for sludge resistance and examine its biosafety in vivo. Using endoscopic retrograde cholangiopancreatography, we placed the PMEA-CSEMS into six normal porcine bile ducts and conventional CSEMS into three normal porcine bile ducts.

A fully covered self-expandable metallic stent coated with poly (2-methoxyethyl acrylate) and its derivative: In vitro evaluation of early-stage biliary sludge formation inhibition.

The adhesion and deformation behavior of proteins at the inner surface of fully covered, self-expandable metallic stents coated with biocompatible polymers, poly(2-methoxyethyl acrylate) (PMEA) and poly(3-methoxypropyl acrylate) (PMC3A), were analyzed. Model bile solution, proteins, and bacteria were used to unravel the inhibitory ability of the polymer coatings. Adsorbance of proteins and adherence of bacteria were both strongly inhibited by the polymer coatings.

Risk factors for technical failure of endoscopic double self-expandable metallic stent placement by partial stent-in-stent method.

Background: Endoscopic double self-expandable metallic stent (SEMS) placement by the partial stent-in-stent (PSIS) method has been reported to be useful for the management of unresectable hilar malignant biliary obstruction. However, it is technically challenging, and the optimal SEMS for the procedure remains unknown. The aim of this study was to identify the risk factors for technical failure of endoscopic double SEMS placement for unresectable malignant hilar biliary obstruction (MHBO).

Measurement of radial and axial forces of biliary self-expandable metallic stents.

Background: Efforts to understand the properties of self-expandable metallic stents (SEMSs) through their mechanical properties have progressed. Among them, radial force (RF) is well known as an expanding force, but axial force (AF) has not been measured before. Correlations of these properties to clinical results are not well known.