Biocompatible crosslinked coating and crosslinkable coating polymer composition for forming such a coating

Abstract

A braided stent (1) for transluminal implantation in body lumens is self-expanding and has a radial expanded configuration in which the angle α between filaments is acute. Some or all of filaments (6,7) are welded together in pairs at each end (4,5) of the stent to provide beads (8), thereby strengthening the stent and assisting its deployment from a delivery device. The stent is preferably completely coated using a biocompatible polymeric coating, said polymer preferably having pendant phosphoryl choline groups. A method of making the stent by braiding and welding is described as well as a delivery device for deploying the device.The present invention provides a biocompatible crosslinked coating and a crosslinkable coating polymer composition for forming such a coating. The biocompatible crosslinked coating may be formed by curing a polymer of 23 mole % (methacryloyloxy ethyl)-2-(trimethylammonium ethyl) phosphate inner salt, 47 mole % lauryl methacrylate, 5 mole % γtrimethoxysilyl propyl methacrylate and 25 mole % of hydroxy propyl methacrylate. The crosslinkable coating polymer may include 23 mole % (methacryloyloxy ethyl)-2-(trimethylammonium ethyl) phosphate inner salt, 47 mole % lauryl methacrylate, 5 mole % γtrimethoxysilyl propyl methacrylate and 25 mole % of hydroxy propyl methacrylate.<?insert-end id="INS-S-00001" ?>

Description

[0001]More than one reissue application has been filed. This reissue application is a divisional of reissue application No. 10 / 180,060, filed Jun. 27, 2002, which is a reissue application of U.S. Pat. No. 6,083,257, which issued on Jul. 4, 2000. The entire disclosure of the prior application, application Ser. No. 10 / 180,060, is considered part of the disclosure of the accompanying divisional reissue application and is hereby incorporated by reference.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates to an implantable stent for transluminal implantation in body lumen, especially found in peripheral and coronary blood vessels, but also for use in bile ducts, urethras or ileums.[0004]2. Description of the Related Art[0005]There are several designs of stents, permanently implantable devices, for transluminal insertion into blood vessels and other lumen to prevent or reverse occlusion thereof. There are three basic categories of device, namely ...

AI Technical Summary

Benefits of technology

[0015]Preferably no filler wire is used in the welding although it may, for some purposes, be useful to include filler wire, for instance where the filler has different, usually greater, radiopacity than the material from which the metal filaments are made. The formation of bead and / or the use of high radiopacity filler material at the join enables the ends of the stent to be made more radiopaque (to X-rays transmitted perpendicular to the axis) than the body of the stent between the ends. This assists in visualisation of the stent during an operation.

[0053]Where the stent is deployed centrally, it is possible for the position of the stent to be readjusted prior to full deployment or alternatively to be removed from the vessel altogether. Where the distal end of the stent is released, only proximal readjustment of the stent is possible when the stent is partially deployed, otherwise the end could become embedded in the vessel wall and cause damage. Likewise, where the proximal end is fully delivered prior to the distal end, the position of the stent can be readjusted in a distal direction but not a proximal direction. The delivery device may allow for the stent to be retracted back into a sleeve after partial deployment, to allow for repositioning.

Problems solved by technology

There are difficulties with the braided stent of this type.

One difficulty is that with a high angle α the change in axial length between the radially expanded and the radially compressed condition is generally high.

This arrangement, however, adds complexity to the manufacture and deployment and it is difficult to allow for the mutual sliding between stent segments without snagging.

Another difficulty with braided stents in general is the tendency of the filaments at the end of the stent to unravel and splay outwards before or after deployment.

This tendency makes the stent difficult to handle and the splayed ends can damage the inside wall of the body vessel in which the stent is deployed.

This makes it difficult to compress the stent into its radially compressed condition.

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