# US 11,298,251 B2 · Radiopaque intraluminal stents comprising cobalt-based alloys with primarily single-phase supersaturated tungsten content > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,298,251 B2 - Document ID: US11298251B2 - Status: Granted - Kind: B2 - Application number: 16/601,259 - Filed: 2019-10-14 - Published: 2020-02-06 - Granted: 2022-04-12 - Earliest claimed: 2010-11-17 - Assignees: Abbott Cardiovascular Systems Inc. - Applicants: Abbott Cardiovascular Systems, Inc. - Inventors: John A. Simpson; Puneet Kamal Singh Gill; Pamela A. Kramer-Brown - Web page: https://patentgrep.com/patent/US11298251B2 ## CPC - A61F 2/82: Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents (stent-grafts for tubular structures of the body other than blood vessels A61F2/04; stent-grafts for blood vessels A61F2/07) - A61F 2/06: Blood vessels - A61L 31/022: {Metals or alloys} - A61L 31/14: Materials characterised by their function or physical properties {, e.g. injectable or lubricating compositions, shape-memory materials, surface modified materials} - A61L 31/18: Materials at least partially X-ray or laser opaque - C22C 19/07: based on cobalt - A61F 2/915: with bands having a meander structure, adjacent bands being connected to each other - A61F 2250/0098: radio-opaque, e.g. radio-opaque markers - C22C 19/05: with chromium - C22C 27/00: Alloys based on rhenium or a refractory metal not mentioned in groups C22C14/00 or C22C16/00 - C22C 27/04: Alloys based on tungsten or molybdenum - C22C 27/06: Alloys based on chromium - A61F: FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS (dental prosthetics A61C) - A61L: METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES (preservation of bodies or disinfecting characterised by the agents employed A01N; preserving, e.g. sterilising, food or foodstuffs A23; preparations for medical, dental or toiletry purposes A61K) - C22C: ALLOYS (treatment of alloys C21D, C22F) ## Abstract Embodiments are directed to radiopaque implantable structures (e.g., stents) formed of cobalt-based alloys that comprise cobalt, chromium, tungsten, and nickel. Tungsten is present above its solubility limit (about 15%), but is still only present as a super-saturated, primarily single-phase material exhibiting an FCC microcrystalline structure. ## Claims ### Claim 1 A radiopaque stent, comprising: a cylindrical main body comprising a cobalt-chromium alloy including cobalt and chromium, the cobalt-chromium alloy including tungsten as a radiopacity increasing element, the tungsten comprising about 20% to about 35% by weight of the cobalt-chromium alloy, the tungsten content being super-saturated, above the solubility limit of tungsten in the cobalt-chromium alloy; wherein the cobalt-chromium alloy further comprises nickel, the nickel being present in a concentration of 5% to about 15% by weight; and wherein the cobalt-chromium alloy exhibits a primarily single-phase FCC solid solution, wherein a second phase of the tungsten is present and makes up no more than 10% volume fraction in the cobalt-chromium alloy, the second phase having an average particle size of less than 5 μm, even with the super-saturated tungsten content. ### Claim 2 (depends on 1) The radiopaque stent of claim 1, wherein the cobalt-chromium alloy comprises cobalt in an amount from about 30% to about 50% by weight of the cobalt-chromium alloy. ### Claim 3 (depends on 1) The radiopaque stent of claim 1, wherein the cobalt-chromium alloy comprises chromium in an amount of about 20% by weight of the cobalt-chromium alloy. ### Claim 4 (depends on 1) The radiopaque stent of claim 1, wherein the cobalt-chromium alloy comprises nickel in an amount of about 10% by weight of the cobalt-chromium alloy. ### Claim 5 (depends on 1) The radiopaque stent of claim 1, wherein the cobalt-chromium alloy is entirely free of molybdenum. ### Claim 6 (depends on 1) The radiopaque stent of claim 1, wherein the cobalt-chromium alloy comprises no more than 1% of silicon, phosphorus, and/or sulfur by weight. ### Claim 7 (depends on 1) The radiopaque stent of claim 1, wherein the cobalt-chromium alloy further comprises manganese in a concentration of up to 5% by weight of the cobalt-chromium alloy. ### Claim 8 (depends on 1) The radiopaque stent of claim 1, wherein the cobalt-chromium alloy further comprises iron in a concentration of up to 5% by weight of the cobalt-chromium alloy. ### Claim 9 (depends on 1) The radiopaque stent of claim 1, wherein the cobalt-chromium alloy further comprises both manganese and iron in a concentration of about 1.5% each, by weight. ### Claim 10 (depends on 1) The radiopaque stent of claim 1, wherein cobalt comprises from about 66 to 68% by weight of the cobalt-chromium alloy. ### Claim 11 (depends on 1) The radiopaque stent of claim 1, wherein a weight percent ratio of tungsten to cobalt is at least 0.4. ### Claim 12 (depends on 1) The radiopaque stent of claim 1, wherein a ratio of tungsten to cobalt is from 0.4 to 1.2. ### Claim 13 (depends on 1) The radiopaque stent of claim 1, wherein a ratio of tungsten to cobalt is from 0.40 to 0.45. ### Claim 14 (depends on 1) The radiopaque stent of claim 1, wherein a ratio of tungsten to cobalt is from 0.57 to 0.63. ### Claim 15 (depends on 1) The radiopaque stent of claim 1, wherein a ratio of tungsten to cobalt is from 1.07 to 1.13. ### Claim 16 (depends on 1) The radiopaque stent of claim 1, wherein the cobalt-chromium alloy is substantially free of carbon. ### Claim 17 A radiopaque stent, comprising: a cylindrical main body formed from a single homogenous cobalt-chromium alloy including cobalt, chromium, nickel, and tungsten, the cobalt-chromium alloy not including any other alloying elements in amounts greater than 3% by weight; the cobalt-chromium alloy including tungsten as a radiopacity increasing element, the tungsten comprising about 20% to about 35% by weight of the cobalt-chromium alloy, the tungsten content being super-saturated, above the solubility limit of tungsten in the cobalt-chromium alloy at ambient temperature; wherein the cobalt-chromium alloy comprises about 10% by weight nickel; and wherein the cobalt-chromium alloy exhibits a primarily single-phase FCC solid solution structure, a second phase of the tungsten is present in the cobalt-chromium alloy having a maximum particle size of less than 15 μm, even with the super-saturated tungsten content. ### Claim 18 (depends on 17) The radiopaque stent of claim 17, wherein the cobalt-chromium alloy is entirely free of molybdenum. ### Claim 19 (depends on 17) The radiopaque stent of claim 17, wherein the cobalt-chromium alloy is substantially free of carbon. ### Claim 20 (depends on 17) The radiopaque stent of claim 17, wherein the cobalt-chromium alloy is entirely free of carbon. ### Claim 21 A radiopaque stent, comprising: a cylindrical main body comprising a cobalt-chromium alloy including cobalt and chromium, the cobalt-chromium alloy including tungsten as a radiopacity increasing element, the tungsten comprising about 20% to about 35% by weight of the cobalt-chromium alloy, the tungsten content being super-saturated, above the solubility limit of tungsten in the cobalt-chromium alloy; wherein the cobalt-chromium alloy further comprises nickel, the nickel being present in a concentration of 5% to about 15% by weight; wherein the cobalt-chromium alloy exhibits a primarily single-phase FCC solid solution, wherein no more than 10% volume fraction of a second phase of the tungsten is present in the cobalt-chromium alloy, the second phase having an average particle size of less than 5 μm, even with the super-saturated tungsten content; and at least one of (i) or (ii): (i) wherein a ratio of tungsten to cobalt is from 1.07 to 1.13; (ii) wherein the cobalt-chromium alloy further comprises both manganese and iron in a concentration of about 1.5% each, by weight. ### Claim 22 (depends on 1) The radiopaque stent of claim 1, wherein the tungsten comprises 25% to about 30% by weight of the cobalt-chromium alloy.