Fiber reinforced composite stents

Abstract

Polymeric composite stents reinforced with fibers for implantation into a bodily lumen are disclosed.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] This invention relates to radially expandable implantable medical devices such as stents for implantation into a bodily lumen. In particular, the invention relates composite stents reinforced with fibers. [0003] 2. Description of the State of the Art [0004] This invention relates to radially expandable endoprostheses, which are adapted to be implanted in a bodily lumen. An “endoprosthesis” corresponds to an artificial device that is placed inside the body. A “lumen” refers to a cavity of a tubular organ such as a blood vessel. [0005] A stent is an example of such an endoprosthesis. Stents are generally cylindrically shaped devices, which function to hold open and sometimes expand a segment of a blood vessel or other anatomical lumen such as urinary tracts and bile ducts. Stents are often used in the treatment of atherosclerotic stenosis in blood vessels. “Stenosis” refers to a narrowing or constriction of the diamet...

AI Technical Summary

Benefits of technology

[0026] Additional embodiments of the present invention are directed to a method of making a stent that may include heating a fiber mesh tube including two types of fibers. A first fiber may include a first polymer and the second fiber may include a second polymer. The first polymer may have a softening temperature lower than a softening temperature of the second polymer. The tube may be heated to a temperature range between the softening temperature of the first polymer and the softening temperature of the second polymer. The method may further include applying pressure to the tube so as to flatten at least some of the fibers of the tube to reduce a radial profile of the tube.

[0027] Some further embodiments of the present invention are directed to a method of making a stent that may include heating a fiber mesh tube. At least some of the fibers of the tube may include a first polymer and a second polymer. The first polymer may have a softening temperature lower than a softening temperature of the second polymer. The tube may be heated to a temperature range between the softening temperature of the first polymer and the softening temperature of the second polymer. The method may further include applying pressure to the tube so as to flatten at least some of the fibers of the tube to reduce a radial profile of the tube.

[0034] Certain embodiments of the present invention are directed to a radially expandable stent woven from at lease two types of fibers. A first fiber may include a first polymer and the second fiber may include a second polymer. The first polymer may have a softening temperature lower than a softening temperature of the second polymer. At least some of the fibers may have a flattened radial profile that reduces the radial profile of the tube.

[0035] Other embodiments of the present invention are directed to a radially expandable stent woven from fibers comprising a first polymer and a second polymer. The first polymer may have a softening temperature lower than a softening temperature of the second polymer such that at least some of the fibers have a flattened radial profile that reduces the radial profile of the tube.

Problems solved by technology

Inadequate radial strength potentially contributes to a relatively high incidence of recoil of polymeric stents after implantation into vessels.

Another potential problem with polymeric stents is that their struts or bar arms can crack during crimping and expansion, especially for brittle polymers.

The localized portions of the stent pattern subjected to substantial deformation tend to be the most vulnerable to failure.

Furthermore, in order to have adequate mechanical strength, polymeric stents may require significantly thicker struts than a metallic stent, which results in an undesirably larger profile.

Additionally, there are manufacturing difficulties in placing small markers on stents as well as challenges in keeping very small markers attached to the stent.

This makes manufacturing even more challenging.

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