CA-3176896-C - BIO-ALLOY BRAIDED SELF-EXPANDING BIODEGRADABLE STENT

Abstract

An implantable device, including: a tube including a plurality of biodegradable biometallic wires braided together, the tube being coated with a flexible conformal biodegradable polymer in an expanded state such that, upon compression and release of compression, the flexible conformal biodegradable polymer-coated tube self-expands back to the expanded state.

Inventors

• Mark Paquin
• David Broecker

Assignees

• Zorion Medical, Inc.

Dates

Publication Date

20260505

Application Date

20210407

Priority Date

20200407

Claims (20)

1. 90136256 CLAIMS: 1.
2. 2. An implantable device, comprising: a tube comprising a plurality of biodegradable biometallic wires braided together, the tube being coated with a flexible conformal biodegradable polymer in an expanded state such that, upon compression and release of compression, the flexible conformal biodegradable polymer-coated tube self-expands back to the expanded state, wherein the tube further comprises one or more radiopaque wires to provide radiopacity to the tube, wherein the one or more radiopaque wires comprises one or more non-degradable radiopaque wires, and wherein the one or more non-degradable radiopaque wires is coated with a permanent polymer coating to inhibit galvanic corrosion. The implantable device of claim 1, wherein at least one of the one or more radiopaque wires comprises a composite wire.
3. 3. The implantable device of claim 1, wherein at least one of the one or more radiopaque wires comprises a magnesium-alloy radiopaque composite wire.
4. 4. The implantable device of claim 3, wherein a diameter of the magnesium-alloy radiopaque composite wire is substantially the same as a diameter of each of the plurality of biodegradable biometallic wires.
5. 5. The implantable device of claim 4, wherein the magnesium-alloy radiopaque composite wire comprises a radiopacifying filler.
6. 6. The implantable device of claim 5, wherein the radiopacifying filler includes at least one of barium, bismuth, tantalum, or tungsten.
7. 7. The implantable device of claim 6, wherein the magnesium-alloy radiopaque composite wire comprises a shell surrounding a core, and 23 90136256 wherein the core comprises the radiopacifying filler and has a higher density than the shell.
8. 8. The implantable device of claim 2, wherein the one or more radiopaque composite wires comprises a shape memory alloy.
9. 9. The implantable device of claim 8, where the shape memory alloy comprises a nickel titanium alloy.
10. 10. The implantable device of any one of claims 1 to 9, wherein the one or more non degradable radiopaque wires comprises a biocompatible radiopaque metal.
11. 11. The implantable device of claim 10, wherein a diameter of the one or more non degradable radiopaque wires is between 25% and 40% smaller than a diameter of each of the plurality of biodegradable biometallic wires.
12. 12. The implantable device of claim 11, wherein the biocompatible radiopaque metal includes at least one of gold, platinum, tantalum, iridium, iron, or tungsten.
13. 13. The implantable device of any one of claims 1 to 12, wherein the permanent polymer coating comprises a dielectric insulating material.
14. 14. The implantable device of claim 13, wherein the permanent polymer coating comprises at least one of polyimide or a fluoropolymer.
15. 15. The implantable device of claim 1, wherein the plurality of biodegradable biometallic wires comprises non-composite magnesium wires.
16. 16. The implantable device of claim 1, wherein the plurality of biodegradable biometallic wires comprises a composite wire.
17. 17. The implantable device of any one of claims 1 to 16, wherein the plurality of biodegradable biometallic wires is substantially free of rare earth elements. 24 90136256
18. 18. The implantable device of any one of claims 1 to 16, wherein the plurality of biodegradable biometallic wires comprises at least 80% w/w magnesium.
19. 19. The implantable device of claim 18, wherein the plurality of biodegradable biometallic wires further comprises at least one of zinc or zirconium.
20. 20. The implantable device of claim 19, wherein the plurality of biodegradable biometallic wires further comprises at least one rare earth element.

Description

90136256 1 BIO-ALLOY BRAIDED SELF-EXPANDING BIODEGRADABLE STENT CROSS-REFERENCE TO RELATED APPLICATIONS [0001] The present application is based on and claims priority from U.S. Patent Application Ser. No. 63/006,565, filed on April 7, 2020. BACKGROUND [0002] Current bioabsorbable stents, typically made of varying amounts of bioplastics and biometals, have significant performance limitations based on the underlying properties of the biomaterials used to make the stent. [0003] Both bioplastics and biometals lack radiopacity, making delivery and tracking of the device difficult, particularly in clinical situations involving precise vessel sizing and implant placement. In addition, bioplastic scaffolds lack inherent strength and flexibility, particular in comparison to non-absorbable materials. [0004] To compensate for certain properties such as lack of strength, stents made from bioplastics generally require more material (i.e., higher mass, greater strut thicknesses), resulting in longer absorption times (i.e., on the order of years rather than months) following implantation. [0005] Biometals have mechanical properties that are more similar to those of nonabsorbable metals; however, to maintain these properties in the implantable device, a limited set of designs and fabrication techniques are available, often resulting in suboptimal performance (e.g., high failure rates due to fracture and/or too rapid degradation) across a narrow set of performance conditions (e.g. vessel diameters) or delivery systems (e.g. balloon-expandable) for deployment. SUMMARY [0006] Accordingly, the present disclosure is directed to improved bioabsorbable devices such as stents which address one or more of the problems identified above, including suboptimal performance and limited applications, either due to poor visibility, stent design, or the biomaterial from which these bioabsorbable stents are made and/or a combination of thereof, and specifically addresses issues involving precise vessel sizing and implant placement of bioabsorbable stents. Magnesium stents, and more particularly, self-expanding, braided wirebased magnesium stents, engineered for more rapid absorption times (e.g., over WO 2021/207366 PCT/0S2021/026192 a period of months rather than years) having enhanced visibility, address one or more limitations associated with current bioabsorbable stents described above and in the prior art. [0007] Disclosed herein are various embodiments of a hybrid self-expanding biodegradable stent (HSEBS). For purposes of the present disclosure, the term "hybrid" generally refers to the incorporation of radiopaque (RO) metallic wires (e.g. single, composite, and/or multi-wire strands) that enhance the visibility (e.g. using radiography or other imaging modalities) of the device for implantation. The term "self-expanding" generally refers to the ability of the device to recover a significant portion of the as-made diameter upon delivery inside a lumen. The term "biodegradable stent" generally refers to the ability of the device to safely absorb following implantation based on the predominance ofbiometal wire components (e.g. single, composite, multi-wire strand) used to make the device. Finally, the term "biometal" and "biometallic" refers to metals that are biocompatible when implanted into a living subject such as a human and which may be biodegradable. The HSEBS may be produced from a braided tube including biodegradable biometallic wires with or without permanently coated RO wires interlaced clockwise and counterclockwise around a mandrel. The addition of radiopaque wires to the HSEBS makes it possible to visualize the entire length of the stent from end-to-end and track the stent during implantation and other procedures. [0008] In various embodiments the biodegradable biometallic wire may be produced from a magnesium-alloy (MA), where the majority of the wire (e.g., at least 80%) may be magnesium. In certain embodiments, the RO wire may be produced from non-degradable metals. In certain embodiments the MA may be made of medical-grade materials and may be free of rare earth elements. [0009] In certain embodiments the MA may be alloyed magnesium ( e.g., greater than 90% w/w Mg) which may also include zinc, calcium, and manganese to produce an alloy that is strong and ductile, and free of rare earth elements, making the alloy suitable for implantation inside various structures including blood vessels, such as arteries and veins. [0010] In particular embodiments the MA may be chemically composed of zinc, zirconium, and rare earth elements with at least 80% w/w of magnesium, where the MA may be biocompatible and have high tensile strength, yield strength, and percent elongation. In some embodiments the biodegradable metal may also include iron and zinc. [0011] In some embodiments, the RO wire may be made from metals having lower elastic modulus and high yield stress for large elastic strains that play both a radiopacity and mechanical r