Bile duct stent and method of manufacturing the same

A bile duct stent comprising:

• a cylindrical body having a mesh structure formed by zigzagging metal wires of a shape memory alloy;
• and
• a backflow-preventing pattern film disposed at an outlet end of the cylindrical body, the backflow-preventing pattern film comprising metal wire lines crossing an outlet opening one time or more to form a network structure,
• wherein the backflow-preventing pattern film forms a radial network structure in which the metal wire lines extend between an outer peripheral region adjacent the outlet end and a center region so as to form a radial pattern, and wherein the radial backflow-preventing pattern film comprises at least three reciprocating line segments of the metal wire lines, each reciprocating line segment passing through the center region and returning toward the outer peripheral region,
• wherein, at the center region, bent portions are formed in the metal wire lines and multiple ones of the metal wire lines are mechanically fixed by intersecting each other in a bent state,
• wherein bent portions of at least three of the reciprocating line segments overlap with one another at a common central point to define a single overlapped central hub region,
• wherein the overlapped central hub region defines a central opening located at the center region, the central opening corresponding to a position at which a vertical pin (Py) is temporarily disposed during formation of the radial backflow-preventing pattern film and absent in a final product, such that the bent portions remain superposed around the central opening and are mechanically fixed to one another at the central hub region,
• wherein the metal wire lines are self-expansile such that, when the bile duct stent is loaded in an inner diameter of a catheter for stent placement and a diameter of the cylindrical body is reduced by an external pressure, the bent portions fold to facilitate loading of the bile duct stent on the catheter, and
• wherein the radial backflow-preventing pattern film is configured to maintain backflow-preventing performance irrespective of deformation of the cylindrical body due to pressure at a lesion site.