Hybrid stent and method of making
A stent is formed by encasing or encapsulating metallic rings in an inner polymeric layer and an outer polymeric layer. At least one polymer link connects adjacent metallic rings. The stent is drug loaded with one or more therapeutic agent or drug, for example, to reduce the likelihood of the development of restenosis in the coronary arteries. The inner and outer polymeric materials can be of the same polymer or different polymer to achieve different results, such as enhancing flexibility and providing a stent that is visible under MRI, computer tomography and x-ray fluoroscopy.
1. A stent, comprising:
a plurality of longitudinally spaced metallic rings aligned along a stent longitudinal axis, none of the metallic rings being connected by a metallic component;
a plurality of links arranged to connect a metallic ring to an adjacent metallic ring;
an outer layer of a first polymeric material covering an outer surface of the metallic rings; and
an inner layer of a second polymeric material covering an inner surface of the metallic rings;
wherein all of the links are formed by the outer layer and the inner layer, said outer layer and inner layer are directly joined to one another to form each link, each link is devoid of any metallic component and an entirety of the inner surface and outer surface of the stent is covered by the first and second polymeric materials.
2. The stent of claim 1 , wherein the first polymeric material is EVOH.
3. The stent of claim 1 , wherein the second polymeric material is PEEK.
4. The stent of claim 3 , wherein the PEEK is radiopaque.
5. The stent of claim 2 , wherein the EVOH is radiopaque.
6. The stent of claim 1 , wherein the first and second polymeric materials are taken from the group of polymers consisting of polyetheretherketone (PEEK), ethyl vinyl alcohol (EVOH), polyetherketone, polymethylmethacrylate, polycarbonate, polyphenylenesulfide, polyphenylene, polyvinylfluoride, polyvinylidene fluoride, polypropylene, polyethylene, poly(vinylidene fluoride-co-hexafluoropropylene), poly(ethylene-co-hexafluoropropylene), poly(tetrafluoroethyelene-co-hexafluoropropylene), poly(tetrafluoroethyelene-co-ethylene), polyethyleneterephthalate, polyimides, polyetherimide, ePTFE, polyurethanes, polyetherurethanes, polyesterurethanes, silicone, thermoplastic elastomer, polyether-amide thermoplastic elastomer, fluoroelastomers, fluorosilicone elastomer, styrene-butadiene-styrene rubber, styrene-isoprene-styrene rubber, polybutadiene, polyisoprene, neoprene, ethylene-propylene elastomer, chlorosulfonated polyethylene elastomer, butyl rubber, polysulfide elastomer, polyacrylate elastomer, nitrile rubber, a family of elastomers composed of styrene, ethylene, propylene, aliphatic polycarbonate polyurethane, polymers augmented with antioxidants, polymers augmented with image enhancing materials, polymers having a proton (H+) core, butadiene and isoprene and polyester thermoplastic elastomer and a di-block co-polymer of PET and caprolactone.
7. The stent of claim 1 , wherein the metallic rings are formed of a metal alloy taken from the group of metal alloys consisting of stainless steel, titanium, tantalum, nickel-titanium, cobalt-chromium, and tungsten.
8. The stent of claim 1 , wherein one or both of the first and second polymeric materials are loaded with a therapeutic drug.
9. The stent of claim 8 , wherein the therapeutic drug is taken from the group of drugs including one or more of everolimus, rapamycin, actinomycin D (ActD), or derivatives and analogs thereof; synonyms of actinopmycin D including dactinomycin, actinomycin IV, actinomycin 11, actinomycin X1, and actinomycin C1; antiproliferative substances including antineoplastic, antinflammatory, antiplatelet, anticoagulant, antifibrin, antithomobin, antimitotic, antibiotic, antioxidant substances, taxol (paclitaxel and docetaxel), anticoagulants, antifibrins, sodium heparin, low molecular weight heparin, hirudin, argatroban, forskolin, vapiprost, prostacyclin and prostacyclin analogs, dextran, D-phe-pro-arg-chloromethylketone (synthetic antithrombin), dipyridamole, glycoprotein, IIb/IIIa platelet membrane receptor antagonist, recombinant hirudin, thrombin inhibitor methotrexate, azathioprine, vincristine, vinblastine, fluorouracil, adriamycin, mutamycin; angiopeptin, angiotensin converting enzyme inhibitors; calcium channel blockers; colchicine fibroblast growth factor (FGF) antagonists; fish oil (omega 3-fatty acid); histamine antagonist; monoclonal antibodies (such as PDGF receptors); nitroprusside; phosphodiesterase inhibitors; prostaglandin inhibitor (a PDGF antagonist); serotonin blockers; steroids; thioprotease inhibitors; triazolopyrimidine (a PDGF antagonist); and nitric oxide.
10. The stent of claim 1 , wherein a radiopaque marker is positioned between the first polymeric material and the second polymeric material.
11. The stent of claim 1 , wherein the outer layer of the first polymeric material has a thickness in the range of 0.001 mm to 2.5 mm.
12. The stent of claim 11 , wherein the outer layer has a uniform thickness.
13. The stent of claim 11 , wherein the outer layer has a variable thickness.
14. The stent of claim 1 , wherein the inner layer of the second polymeric material has a thickness in the range of 0.001 mm to 2.5 mm.
15. The stent of claim 14 , wherein the inner layer has a uniform thickness.
16. The stent of claim 14 , wherein the inner layer has a variable thickness.
17. The stent of claim 1 , wherein the metallic rings have an undulating pattern.
18. The stent of claim 17 , wherein the undulating pattern includes U-shaped elements.
19. The stent of claim 1 , wherein the stent is configured so that it is visible under any of x-ray fluoroscopy, computer tomography, or MRI.
20. The stent of claim 1 , wherein a cavity is formed between the first polymeric material and the second polymeric material so that a therapeutic drug can be releasably contained within the cavity.
21. The stent of claim 1 , wherein the metallic rings are formed of struts, the struts having a substantially uniform radial thickness.
22. The stent of claim 1 , wherein the metallic rings are formed of struts, the struts having a variable radial thickness.
23. The stent of claim 1 , wherein the first polymeric material is a shape memory polymer.
24. The stent of claim 23 , wherein the shape memory polymer includes the family of polymers oligo (e-caprolactone) dimethacrylate combined with n-butyl acrylate.
25. The stent of claim 1 , wherein the first polymeric material and the second polymeric material are the same material.
26. The stent of claim 1 , wherein each link has a substantially rectangular cross section.
27. The stent of claim 26 , wherein each link has an undulating pattern.
28. The stent of claim 1 , wherein a plurality of open cells devoid of any of the inner and outer layers are formed between each adjacent metallic ring.
29. A stent, comprising:
a plurality of longitudinally spaced apart metallic rings aligned along a stent longitudinal axis;
an outer layer of a first polymeric material covering an outer surface of the metallic rings; and
an inner layer of a second polymeric material covering an inner surface of the metallic rings, wherein the inner and outer layers are directly joined to one another in the space between each adjacent ring to form a plurality of links which exclusively connect a metallic ring to an adjacent metallic ring.
30. The stent of claim 29 , wherein the first polymeric material is EVOH.
31. The stent of claim 29 , wherein the second polymeric material is PEEK.
32. The stent of claim 31 , wherein the PEEK is radiopaque.
33. The stent of claim 30 , wherein the EVOH is radiopaque.
34. The stent of claim 29 , wherein the first and second polymeric materials are taken from the group of polymers consisting of polyetheretherketone (PEEK), ethyl vinyl alcohol (EVOH), polyetherketone, polymethylmethacrylate, polycarbonate, polyphenylenesulfide, polyphenylene, polyvinylfluoride, polyvinylidene fluoride, polypropylene, polyethylene, poly(vinylidene fluoride-co-hexafluoropropylene), poly(ethylene-co-hexafluoropropylene), poly(tetrafluoroethyelene-co-hexafluoropropylene), poly(tetrafluoroethyelene-co-ethylene), polyethyleneterephthalate, polyimides, polyetherimide, ePTFE, polyurethanes, polyetherurethanes, polyesterurethanes, silicone, thermoplastic elastomer, polyether-amide thermoplastic elastomer, fluoroelastomers, fluorosilicone elastomer, styrene-butadiene-styrene rubber, styrene-isoprene-styrene rubber, polybutadiene, polyisoprene, neoprene, ethylene-propylene elastomer, chlorosulfonated polyethylene elastomer, butyl rubber, polysulfide elastomer, polyacrylate elastomer, nitrile rubber, a family of elastomers composed of styrene, ethylene, propylene, aliphatic polycarbonate polyurethane, polymers augmented with antioxidants, polymers augmented with image enhancing materials, polymers having a proton (H+) core, butadiene and isoprene and polyester thermoplastic elastomer and a di-block co-polymer of PET and caprolactone.
35. The stent of claim 29 , wherein the metallic rings are formed of a metal alloy taken from the group of metal alloys consisting of stainless steel, titanium, tantalum, nickel-titanium, cobalt-chromium, and tungsten.
36. The stent of claim 29 , wherein one or both of the first and second polymeric materials are loaded with a therapeutic drug.
37. The stent of claim 36 , wherein the therapeutic drug is taken from the group of drugs including one or more of everolimus, rapamycin, actinomycin D (ActD), or derivatives and analogs thereof; synonyms of actinopmycin D including dactinomycin, actinomycin IV, actinomycin 11, actinomycin X1, and actinomycin C1; antiproliferative substances including antineoplastic, antinflammatory, antiplatelet, anticoagulant, antifibrin, antithomobin, antimitotic, antibiotic, antioxidant substances, taxol (paclitaxel and docetaxel), anticoagulants, antifibrins, sodium heparin, low molecular weight heparin, hirudin, argatroban, forskolin, vapiprost, prostacyclin and prostacyclin analogs, dextran, D-phe-pro-arg-chloromethylketone (synthetic antithrombin), dipyridamole, glycoprotein, IIb/IIIa platelet membrane receptor antagonist, recombinant hirudin, thrombin inhibitor methotrexate, azathioprine, vincristine, vinblastine, fluorouracil, adriamycin, mutamycin; angiopeptin, angiotensin converting enzyme inhibitors; calcium channel blockers; colchicine fibroblast growth factor (FGF) antagonists; fish oil (omega 3-fatty acid); histamine antagonist; monoclonal antibodies (such as PDGF receptors); nitroprusside; phosphodiesterase inhibitors; prostaglandin inhibitor (a PDGF antagonist); serotonin blockers; steroids; thioprotease inhibitors; triazolopyrimidine (a PDGF antagonist); and nitric oxide.
38. The stent of claim 29 , wherein a radiopaque marker is positioned between the first polymeric material and the second polymeric material.
39. The stent of claim 29 , wherein the stent is configured so that it is visible under any of x-ray fluoroscopy, computer tomography, or MRI.
40. The stent of claim 29 , wherein a cavity is formed between the first polymeric material and the second polymeric material so that a therapeutic drug can be releasably contained within the cavity.
41. The stent of claim 29 , wherein the first polymeric material is a shape memory polymer.
42. The stent of claim 41 , wherein the shape memory polymer includes the family of polymers oligo (e-caprolactone) dimethacrylate combined with n-butyl acrylate.
43. The stent of claim 29 , wherein the first polymeric material and the second polymeric material are the same material.
44. The stent of claim 29 wherein each link has a substantially rectangular cross section.
45. The stent of claim 44 , wherein each link has an undulating pattern.
46. The stent of claim 29 , wherein a plurality of open cells devoid of any of the inner and outer layers are formed between each adjacent metallic ring.