EP0797963A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Stents and stent-grafts
Assignee: Corvita Corp
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Filing: 1997-03-25
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Granted: —
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Expires: 2017-03-25
Abstract
Abstract Stents are coated with a polymer such that the polymeric coating binds the crossover points of the wires, or, in the case of a zig-zag stent, binds adjacent zig-zags of wires without occluding the interstices of the stent lattice. Suitable polymers include polyurethane, polycarbonate urethane, polyurethane urea, silicone rubber, polyisobutylene copolymer (with styrene, etc.), polyolefin, polyester, glycolated polyester, polyamide, amorphous polyamide, combinations of the above and the like. Biodegradable polymers such as polyisobuterate, polyvalerate, polylactic acid, polyglycolic acid and combinations of these are also suitable. The polymer can be reacted in place without a solvent, such as two component polyurethanes, or silicone rubbers, or the reacted polymer can be dissolved in an appropriate solvent, for example, dimethylacetamide for the polyurethanes, toluene for the polyolefins, or heptane for the silicone rubbers. In order to enhance bonding of the polymer to the stent wires, the metallic stent can be primed prior to coating. The hoop strength of a polymer coated stent is improved due to locking of the crossover points and preventing free motion of the stent wires relative to each other.
Inventors
- 👤 Leonard Pinchuk
- 👤 Noureddine Frid
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-23 19:15
CPC Classifications
A; A61; A61F; A61F2/00; A61F2/82; A61F2/86; A61F2/90; A61M; A61M25/00; A61F2/02; A61F2/04; A61F2/06; A61F2/07; A61F2/0077; A61F2/89; A61F2002/072; A61F2002/075; A61F2240/00; A61F2240/001
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
104 words
A prosthesis having a radially and axially flexible substantially cylindrical body and formed of either a plurality of wire filaments having crossing points defining a lattice of interstices between wire filaments, or of a helically wound zig-zag wire filament with adjacent zig-zags defining a lattice of interstices, the improvement characterized in that a polymer coating is provided on said wire filaments at said crossing points or to said helicaly wound wire filament at said zig-zags so that said wire filaments or adjacent zig-zags are bound to each other by said polymer and said interstices of said lattice are not substantially occluded by said polymer.
Claim 2
Dependent Claim
39 words
A prosthesis according to claim 1, wherein: said polymer coating is an aromatic polycarbonate urethane coating having a Shore hardness of 80A to 100D, and preferably between 55D and 75D, said polymer coating optionally including a drug eluting polymer.
Claim 3
Dependent Claim
29 words
A prosthesis according to any previous claim, wherein: said filament(s) are coated with at least one layer, and preferably several layers of said polymer along substantially their entire lengths.
Claim 4
Dependent Claim
44 words
A prosthesis according to any previous claim, wherein: said filament(s) and said polymer are chosen such that a hoop strength of said body with said polymer is increased by at least 25% over a second hoop strength of a similar body without said polymer.
Claim 5
Dependent Claim
49 words
A prosthesis according any previous claim, further comprising: a porous vascular graft attached to said body, said graft preferably comprised of a spun polycarbonate urethane liner having a melting point of approximately 160°C, and said polymer preferably comprised of a polycarbonate urethane having a melting point of approximately 240°C.
Claim 6
Dependent Claim
43 words
A prosthesis according to claim 5, wherein; said porous vascular graft comprises two spun polycarbonate urethane liners, one being placed inside said body and another being placed over said body, said liners being bonded to each other through said interstices of said lattice.
Claim 7
Independent Claim
104 words
A method of making a prosthesis, comprising: a) obtaining a radially and axially flexible substantially cylindrical body formed either from a plurality of filaments having crossing points defining a lattice of interstices between filaments, or from a helically wound zig-zag filament with adjacent portions of the zig-zags defining the lattice of interstices; b) applying a polymeric solution to the crossing points or adjacent portions of zig-zags; and c) allowing the polymeric solution to cure such that crossing filaments or adjacent portions of zig-zags are bound to each other by the polymer and the interstices of the lattice are not substantially occluded by the polymer.
Claim 8
Dependent Claim
47 words
A method according to claim 7, wherein: the polymeric solution contains a polycarbonate urethane of approximately Shore 50D to 75D dissolved in dimethylacetamide, and optionally further includes one or more of (i) a biodegradable mixture of polybuterate and polyvalerate dissolved in chloroform, and (ii) the drug 5-fluorouracil.
Claim 9
Independent Claim
41 words
A method according to either of claims 7 or 8, wherein: the filament(s) is/are wire filaments, and the polymeric solution is sprayed onto the filament(s) and cured by drying, and the spraying/drying cycle is preferably repeated between five and fifteen times.
Claim 10
Independent Claim
22 words
A method according to any of claims 7-9, further comprising: d) attaching a porous graft to the filament(s) to form a stent-graft.
Claim 11
Dependent Claim
51 words
A method according to claim 10, wherein: the porous graft is formed by spinning a polycarbonate urethane having a melting point of approximately 160°C onto a rotating mandril, curing the graft, spinning first additional polycarbonate urethane onto the cured graft, placing the stent over the graft, and curing the stent-graft assembly.
Claim 12
Dependent Claim
45 words
A method according to claim 11, wherein: the graft is further formed by spinning second additional polycarbonate urethane onto the stent-graft assembly, and pressing the second additional polycarbonate urethane through the interstices to bond the second additional polycarbonate urethane to the first additional polycarbonate urethane.
Claim 13
Independent Claim
34 words
A method according to any of claims 7-12, further comprising: coating the cured polymer with a solution containing phospholipid such that a thin layer of phospholipid is bound to the surface of the polymer.
Claim 14
Independent Claim
47 words
A method according to any of claims 7-13, further comprising: either prior to applying the polymeric solution or after the polymeric solution has cured, pressing or forcing conical inserts into at least a first end of the substantially cylindrical body such that the first end is flared.
Claim 15
Dependent Claim
41 words
A method according to claim 14, further comprising: heating the substantially cylindrical body with said first end flared to approximately 170° - 200°C until the polymer is partially melted; and cooling the substantially cylindrical body and the mandril to room temperature.
Claim 16
Independent Claim
51 words
A method according to any of claims 7-15, further comprising: prior to applying the polymeric solution, dipping the substantially cylindrical body in a priming solution preferably comprised of 2% aminopropylaminoethyltrimethoxysilane dissolved in a substantially 95%/5% mixture of ethanol and water; and drying the substantially cylindrical body before applying the polymeric solution.
Claim 17
Independent Claim
78 words
A method of making a prosthesis, comprising: a) applying a polymeric solution to wire filaments by pulling the wire filaments through an extruder die to form coated wire filaments; b) forming the coated wire filaments into a substantially cylindrical body with the coated wire filaments adjacent each other at certain locations; c) curing the polymeric solution so that the coated wire filaments are adhered to each other at said certain locations, thereby defining a lattice of non-occluded interstices.
Claim 18
Dependent Claim
34 words
A method according to claim 17, wherein: the polymeric solution is an FEP polymer having a melting point of approximately 420°C, and said step of curing includes heating to approximately 420°C with subsequent cooling.
References Cited (Backward Citations)
No citation records indexed.
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