Hydrogel jacketed stents

Abstract

Hydrogel jacketed stents provide the ability to fill in the stent frame in vivo to at least partially cover the interior of the surface of the stent following deployment while having the convenience of attaching the jacket to the exterior of the stent. The hydrogel can be pleated and/or folder over the exterior of the stent to provide for extension of the stent without damaging the hydrogel. The hydrogel sheet can be secured at one or more points along the circumference to associate the sheet of hydrogel with the exterior surface of the stent frame. The stent can be conveniently delivered using similar technology as conventional stents if desired. The hydrogel can provide for drug delivery if desired.

What is claimed is: 
     
         1 . A method of forming a hydrogel jacketed stent, the method comprising securing a hydrogel sheet over an extendable stent frame in a low profile configuration, wherein the jacketed stent has a generally cylindrical shape, wherein the hydrogel is structured to provide for expansion in diameter by at least of the stent frame by a factor of at least about 2 and wherein the hydrogel expands upon hydration to a thickness at least about 1.5 times the initial thickness of the sheet. 
     
     
         2 . The method of  claim 1  wherein hydrogel jacket is folded and/or pleated around the stent frame such that the hydrogel jacket unfolds when the stent scaffolding deployed to an extended configuration with a greater diameter. 
     
     
         3 . The method of  claim 1  wherein the hydrogel sheet is secured along a point on the circumference of the stent frame. 
     
     
         4 . The method of  claim 1  wherein the stent frame has an inner surface, an exterior surface, an extended configuration and an un-extended diameter, and the hydrogel sheet is associated with the exterior surface such that the hydrogel sheet forms a tubular jacket over and around the circumference of the stent frame upon extension of the stent frame to its extended configuration. 
     
     
         5 . The method of  claim 1  wherein the stent frame is non-self extendable and has an open wall, wherein the hydrogel sheet has a dry thickness from 0.05 mm to 0.3 mm, and wherein the hydrogel sheet is secured along a plurality of points on the circumference of the stent frame. 
     
     
         6 . The method of  claim 1  wherein the stent frame comprises a metal and wherein the hydrogel sheet comprises polyurethanes, polyacrylic acid and esters thereof, polymethacrylic acid and esters thereof, polyacrylonitrile, polyethylene glycol and derivatives thereof, polyacrylamide, epoxy polymers, copolymers thereof or mixtures thereof. 
     
     
         7 . The method of  claim 1  further comprising forming the hydrogel sheet in a cylindrical format. 
     
     
         8 . A method for forming a delivery system for a stent, the method comprising placing a hydrogel jacketed stent over an uninflated balloon on a balloon catheter, wherein the hydrogel jacketed stent is formed by the method of  claim 1 . 
     
     
         9 . The method of  claim 8  further comprising placing a sheath over the catheter covering the hydrogel jacketed stent. 
     
     
         10 . A method for the delivery of a hydrogel jacketed stent comprising extending the stent to an extended configuration within the lumen of a vessel within a patient, wherein the stent comprises an open structured stent frame having an outer surface and a hydrogel jacket associated with the outer surface, wherein the extended stent has the hydrogel jacket secured between the vessel wall and the stent frame such that the hydrogel hydrates and expands to fill the open portions of the stent frame after sufficient time to provide for hydration of the hydrogel. 
     
     
         11 . The method of  claim 10  further comprising positioning the stent in an unextended configuration on a balloon catheter in a blood vessel at a selection position for delivery. 
     
     
         12 . The method of  claim 11  wherein the selected position is within a coronary artery 
     
     
         13 . The method of  claim 12  wherein the stent frame is non-self extendable and has an open wall, wherein the hydrogel sheet has a dry thickness from 0.05 mm to 0.3 mm, and wherein the hydrogel sheet is secured along a plurality of points on the circumference of the stent frame. 
     
     
         14 . The method of  claim 10  wherein the hydrogel jacketed stent is covered with a sheath during delivery, and the method further comprising withdrawing the sheath in a proximal direction to expose the hydrogel jacketed stent prior to extending the stent. 
     
     
         15 . The method of  claim 14  wherein the sheath is designed to control hydration of the hydrogel when the sheath is covering the hydrogel jacketed stent. 
     
     
         16 . The method of  claim 10  wherein the hydrogel sheet is configured in a cylindrical shape in its unextended configuration. 
     
     
         17 . The method of  claim 10  wherein the hydrogel jacket is folded and/or pleated around the stent frame such that the hydrogel jacket unfolds when the stent scaffolding deployed to an extended configuration with a greater diameter. 
     
     
         18 . The method of  claim 10  wherein the hydrogel sheet has a dry thickness from 0.05 mm to 0.3 mm. 
     
     
         19 . The method of  claim 10  wherein the stent frame has an inner surface, an exterior surface, an extended configuration and an un-extended diameter, and the hydrogel sheet is associated with the exterior surface such that the hydrogel sheet forms a jacket over and around the circumference of the stent frame upon extension of the stent frame to its extended configuration. 
     
     
         20 . The method of  claim 10  the stent frame comprises a metal and wherein the hydrogel sheet comprises polyurethanes, polyacrylic acid and esters thereof, polymethacrylic acid and esters thereof, polyacrylonitrile, polyethylene glycol and derivatives thereof, polyacrylamide, epoxy polymers, copolymers thereof or mixtures thereof.