FLEXIBLE EXPANDABLE STENT AND METHOD FOR MANUFACTURING THE SAME

摘要

Pressure expandable stent for use in a blood vessel or other duct of a human body is provided with a high hoop strength, improved flexibility and minimal adverse effects. The stent includes a plurality of unitary circular members (2, 18, 20, 26) of a generally cylindrical shape made from an appropriate metal alloy and successively arranged along a longitudinal axis of the sent. All or at least a part of the unitary circular members are connected to each other by a single connecting component (7, 76) or by connecting components (71, 72, 73, 74) made of a thin, flexible, non-rigid biocompatible material other than metal. One preferred example of non-rigid biocompatible material is polytetrafluoroethylene. Another group of the preferred materials is constituted by biodegradable polymers. Some of the preferred embodiments of the invention contemplate the use of connecting components in the shape of one or a plurality of threads (7, 73, 75) or thin bands (71, 72, 73). Another preferred embodiment uses as the connecting component a mesh (76) consisting of a plurality of threads (77) of non-rigid biocompatible material, with each thread following a helical path. According to one of the preferred embodiment of the method of manufacture of the stent, producing the string of interconnected circular members includes steps of (a) mounting circular members (18) which are to be connected into one or more strings onto a periphery of a mandrel (40) of essentially cylindrical shape; (b) tightly covering said unitary circular members (18) on the mandrel (40) by a detachable cover (60) of an impermeable material, the cover (60) having a through cut (66) or cuts shaped and dimensioned in correspondence to the shape(s) and dimension of one or several of the connecting components to be formed, and (c) applying to unitary circular members (18), through the cut (66) or cuts in the mandrel, (40) a layer of a liquid material which, when solidified, forms the connecting elements of elements.