US20050098241A1 - Niobium-Zirconium Alloy for medical devices or their parts - Google Patents

Niobium-Zirconium Alloy for medical devices or their parts Download PDF

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Publication number
US20050098241A1
US20050098241A1 US10/705,566 US70556603A US2005098241A1 US 20050098241 A1 US20050098241 A1 US 20050098241A1 US 70556603 A US70556603 A US 70556603A US 2005098241 A1 US2005098241 A1 US 2005098241A1
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United States
Prior art keywords
medical implant
metal alloy
device according
weight percent
medical
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US10/705,566
Inventor
Hans-Jurgen Wachter
Jens Trotzschel
Matthias Frericks
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Heraeus Precious Metals GmbH and Co KG
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WC Heraus GmbH
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Filing date
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Priority to US10/705,566 priority Critical patent/US20050098241A1/en
Assigned to W.C. HERAEUS GMBH & CO., KG reassignment W.C. HERAEUS GMBH & CO., KG ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: WACHTER, HANS-JURGEN, FRERICKS, MATTHIAS, TROTZSCHEL, JENS
Publication of US20050098241A1 publication Critical patent/US20050098241A1/en
Assigned to HERAEUS PRECIOUS METALS GMBH & CO. KG reassignment HERAEUS PRECIOUS METALS GMBH & CO. KG ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: W.C. HERAEUS GMBH & CO. KG
Application status is Abandoned legal-status Critical

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Classifications

    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61LMETHODS 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
    • A61L31/00Materials for other surgical articles, e.g. stents, stent-grafts, shunts, surgical drapes, guide wires, materials for adhesion prevention, occluding devices, surgical gloves, tissue fixation devices
    • A61L31/02Inorganic materials
    • A61L31/022Metals or alloys
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61LMETHODS 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
    • A61L27/00Materials for grafts or prostheses or for coating grafts or prostheses
    • A61L27/02Inorganic materials
    • A61L27/04Metals or alloys
    • A61L27/047Other specific metals or alloys not covered by A61L27/042 - A61L27/045 or A61L27/06
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61LMETHODS 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
    • A61L29/00Materials for catheters, medical tubing, cannulae, or endoscopes or for coating catheters
    • A61L29/02Inorganic materials

Abstract

A medical implant or device which is at least partially fabricated from a metal alloy consisting essentially of (a) 98.85-99.15 weight percent Niobium, (b) 0.85-1.15% weight percent Zirconium.

Description

  • The present invention relates to a Niobium-Zirconium Alloy for medical implants or devices to be inserted into the human body for a prolonged period of time.
  • BACKGROUND OF THE INVENTION
  • A medical implant or device must satisfy a number of requirements. When the material for manufacturing these devices is chosen, factors like biocompatibility and a range of mechanical properties have to be considered. The material must not cause any inflammatory reaction or allergic reaction. Commonly used materials often include nickel, like medical grade 316L stainless steel, which contains about 16% nickel. For patients with an allergic reaction the implantation of such materials is contraindicated. Another consideration in material selection is the need for the implanting physician to be able to visualize the position of the medical implant or device during procedure to the desired target site in the body, and for purposes of examination from time to time thereafter at the implant site, typically by X-ray fluoroscopy.
  • With the growing importance of magnetic resonance imaging (MRI), MRI compatibility is desirable. The metal alloys commonly used for implantation (like stainless steel 316) induce a local disturbance of the magnetic field used in MRI, to the extent that imaging of surrounding tissue is impeded. Although alloys like Nitinol behave more favourably in MRI, their MRI compatibility is not considered to be sufficiently good.
  • This invention relates to medical devices or implants in general such as catheters, guide wires, stents, stent grafts and heart valve repair devices.
  • Stents are generally thin walled tubular-shaped devices composed of complex patterns of interconnecting struts which function to hold open a segment of a blood vessel or other body lumen like oesophagus and urethra. Stent grafts are stents with a circumferential covering or lining and are suitable for supporting a dissected artery or intimal flap that can occlude a vessel lumen. Stents and stent grafts are typically implanted by use of a catheter. Initially they are maintained in a radially compressed state to manoeuvre them through the lumen. Once in position, they are deployed. The material from which the vascular prosthesis like stents or stent grafts is constructed must allow the prosthesis to undergo expansion, which typically requires substantial deformation. Once expanded the stent must maintain its size and shape and must be capable of withstanding the structural loads, namely radial compressive forces, imposed on the stent as it supports the walls of a vessel lumen. The wall of the prosthesis must be sufficiently thick, depending on the stent material, not only to withstand the vessel wall recoil but also allow the stent to be seen on the fluoroscope. Finally, the prosthesis material must be biocompatible so as not to trigger any adverse vascular responses like restenosis or thrombus formation in the treated vessel.
  • For medical devices such as all kind of catheters and guide wires special mechanical properties are desired to have perfect trackability and pushability during the intervention. Moreover, good radio-opacity and MRI compatibility are essential in order to survey medical procedures via x-ray and MRI. Finally also for these medical devices biocompatibility is a must.
  • In the past years increased effort was undertaken to find new materials for medical implants and devices bearing superior characteristics over commonly used metals like stainless steel or titanium. Numerous publications focus on titanium alloys aiming at corrosion resistant, high strength and biocompatible alloys. As described for example in U.S. Pat. No. 6,312,455, U.S. 2001/0007953, and WO 99/58184 many Titanium-alloys thereof are super-elastic or shape memory alloys. A pseudo-elastic β-titanium alloy fabricated from Titanium, Molybdenum, Aluminium and optionally Niobium, Chrome and Vanadium is described in U.S. Pat. No. 6,258,182. EP 0 788 802 provides a self-expanding stent consisting of a titanium alloy including at least about 68 weight percent titanium and optionally Niobium, Zirconium, and Molybdenum. U.S. Pat. No. 6,238,491 and WO 00/68448 describe a Niobium-Titanium-Zirconium-Molybdenum alloy for medical devices providing a uniform β-structure, which is corrosion resistant, and can be processes to develop high-strength and low-modulus. The alloy comprises 29 to 70 weight percent Niobium, 10 to 46 weight percent Zirconium, 3 to 15 weight percent Molybdenum and a balance of Titanium. In another approach Davidson (EP 0 601 804) employ an alloy consisting essentially of Titanium, 10 to 20 or 25 to 50 weight percent Niobium and optionally up to 20 weight percent Zirconium, the alloy having an elastic modulus less than 90 GPa. Similar Titanium-alloys for medical implants also published by Davidson comprise Titanium, 10 to 20 or 35 to 50 weight percent Niobium and optionally up to 20 weight percent each Zirconium and Tantalum (EP 0 437 079) or Titanium, 10 to 20 or 35 to 50 weight percent each Niobium and Tantalum and optionally up to 20 weight percent Zirconium (U.S. Pat. No. 5,690,670). EP 0 707 085 also provides a low modulus, biocompatible Titanium-base alloy for medical devices consisting of 20 to 40 weight percent
  • Niobium, 4,5 to 25 weight percent Tantalum, 2,5 to 13 weight percent Zirconium and the balance Titanium. A further high strength, low modulus and biocompatible Titanium-alloy is laid open in U.S. Pat. No. 4,857,269 and EP 0 359 446 consisting of Titanium and up to 25 weight percent Niobium, Zirconium, and Molybdenum. EP 1 046 722 describes a corrosion resistant Titanium-Zirconium-type alloy for medical appliances consisting of 25 to 50 weight percent Titanium, 5 to 30 weight percent Niobium, 5 to 40 weight percent Tantalum and 25 to 60 weight percent Zirconium.
  • OBJECT OF THE INVENTION
  • It is an object of the present invention to provide medical implants or devices, especially stents which have favourable mechanical properties, excellent biocompatibility, good radio-opacity while at the same time exhibiting minor image artefact in MRI examination (MRI compatibility) and does therefore overcome the drawbacks of recently available metals for medical purposes.
  • The material should fulfil all mechanical and structural requirements according to its function in a medical implant or device. Moreover, the material should be sufficiently radio-opaque to allow for good imaging of the device under x-ray without the addition of an extra layer or portion of radio-opaque material. Also, the material should not overly bright in X-ray imaging and should not obscure the image of the surrounding tissue, as would be the case with a device made from an extremely dense material. In addition, the material should be MRI safe and compatible, preferably also visible under MRI.
  • SUMMARY OF THE INVENTION
  • Surprisingly, it has been found that the desired properties can be given to a metal alloy essentially consisting of niobium and 0.85 to 1.15% of zirconium.
  • DETAILED DESCRIPTION OF THE INVENTION
  • The radio-opacity of the presently claimed Nb-Zr alloy is sufficient to be readily visualized under x-ray during medical procedures and yet is not so radio-opaque as to interfere with the visualization of surrounding body tissue.
  • The material is generally an alloy of about 99% of Zr, rest Nb (Nb-1% Zr or NbZr1)—known for long as a reactor tubing material and for various other applications. It can easily be obtained in sheet or tube form. It is especially suitable for stents which require delicate and complicated patterns to be cut from the sheet or tube. The cutting is usually done by laser methods. Stents with low wall thickness may conveniently be manufactured.
  • The alloy of the invention can be easily cold-worked to increase strength and reduce elastic modulus. It is possible to form a hard, abrasion resistant surface on the inventive alloy through standard oxidation and nitridizing methods known by those skilled in the art. The presence of a hard, inert, abrasion resistant surface layer presents an important option for medical implants and devices in which it is desirable to have lower friction and wear, electrical insulation and improved corrosion resistance.
  • To further improve the biocompatibility of the medical implant or device fabricated at least in part from the inventive alloy, at least a portion of the surface of the inventive alloy can be conversion surface hardened and/or coated. Such coatings can include, but are not limited to a polymer, a blend of polymers, a metal, a blend of metals, a ceramic and/or biomolecules, in particular peptides, proteins, lipids, carbohydrates and/or nucleic acids (e.g. collagen, heparin, fibrin, phosphorylcholine, cellulose, morphogenic proteins or peptides, growth factors). Furthermore the alloy surface or the coatings can comprise stem cells and/or a bioactive substances, in particular drugs, antibiotics, growth factors, anti-inflammatory agents and/or anti-thrombogenic agents. Further, the surface can be modified by electropolishing or mechanical polishing for formation of a completely smooth surface, sintering to achieve a porous coating as for example described in EP0601804, or by roughening procedures or microblasting, in particular sandblasting, to achieve a rough surface.
  • The Nb-Zr alloy is useful in the manufacturing of a variety of medical implants and devices. The manufacture of medical devices from the invention alloy includes minimal-invasive devices, in particular guide wires, catheters (balloon catheters, guiding catheter, angiographic catheters, functional catheters), intra-cavernous implants, in particular intra-oesophagus, intra-urethra, intra-tracheal implants and intra-vascular implants, in particular stents, stent grafts, stent graft connector, heart valve repair device or filters.
  • The invention relates to medical implants or devices fabricated from the above-mentioned alloys, e.g. minimal-invasive devices, in particular catheters or guide wires, or intra-cavernous implants, in particular intravascular implants, such as stents, stent grafts, stent graft connectors or heart valve repair devices.
  • In the above implants and devices the surface of the metal alloys may be passivated by oxidation or nitridization, or may be electropolished, mechanically polished, micro blasted, roughened or sintered, or may be coated with a polymer, a blend of polymers, a metal, a blend of metals, a ceramic and/or biomolecules, in particular peptides, proteins, lipids, carbohydrates and/or nucleic acids; or may be coated with stem cells and/or a bioactive substance, in particular drugs, antibiotics, growth factors, anti-inflammatory agents and/or anti-thrombogenic agents.
  • A preferred material for the implants or devices of the invention is the following (All percentages are by weight): 98.85-99.15 weight percent Niobium and 0.85-1.15% Zirconium, preferably 99.05-99.15 weight percent Niobium, and 0.85-0.95% weight percent Zirconium. Especially preferred is the material: 99.05-99.15 weight percent Niobium and 0.85-0.95% weight percent Zirconium.

Claims (14)

1. A medical implant or device at least partially fabricated from a metal alloy consisting essentially of
(a) 98.85-99.15 weight percent Niobium,
(b) 0.85-1.15% weight percent Zirconium.
2. A medical implant or device according to claim 1 wherein said metal alloy consists essentially of
(a) 99.02-99.15 weight percent Niobium,
(b) 0.85-0.98% weight percent Zirconium.
3. A medical implant or device according to claim 1 wherein said metal alloy consists essentially of
(a) 99.05-99.15 weight percent Niobium,
(b) 0.85-0.95% weight percent Zirconium.
4. A medical device according to any one of claims 1 to 3, wherein the medical device is a minimal-invasive device, in particular a catheter or a guide wire.
5. A medical implant or device according to any one of the claims 1 to 3, wherein the medical implant is an intra-cavernous implant.
6. A medical implant or device according to claim 5, wherein the medical implant is an intravascular implant.
7. A medical implant according to claim 6, wherein the medical implant is a stent, a stent graft, a stent graft connector or a heart valve repair device.
8. A stent according to claim 7 which is composed of a single homogeneous, substantially non-decomposing tubing made from the metal alloy according of claim 1.
9. A stent according to claim 8 which is composed of a single homogeneous substantially non-decomposing sheet made from the metal alloy according of claim 1.
10. A medical implant or device according to any one of claims 1-3, wherein the surface of the metal alloy is passivated by oxidation or nitridization.
11. A medical implant or device according to any one of claims 1-3, wherein the surface of the metal alloy is coated with iridium oxide by vapor deposition.
12. A medical implant or device according to any one of claims 1-3, wherein the surface of the metal alloy is electropolished, mechanically polished, micro blasted, roughened or sintered.
13. A medical implant or device according to any one of claims 1-3, wherein the surface of the metal alloy is coated with a polymer, a blend of polymers, a metal, a blend of metals, a ceramic and/or biomolecules, in particular peptides, proteins, lipids, carbohydrates and/or nucleic acids.
14. A medical implant or device according to any one of claims 1-3, wherein the surface of the metal alloy is coated with stem cells and/or a bioactive substance, in particular drugs, antibiotics, growth factors, anti-inflammatory agents and/or anti-thrombogenic agents.
US10/705,566 2003-11-11 2003-11-11 Niobium-Zirconium Alloy for medical devices or their parts Abandoned US20050098241A1 (en)

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US10/705,566 US20050098241A1 (en) 2003-11-11 2003-11-11 Niobium-Zirconium Alloy for medical devices or their parts
PCT/EP2004/012343 WO2005044327A1 (en) 2003-11-11 2004-11-01 Niobium-zirconium alloy for medical devices or their parts

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Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20060204535A1 (en) * 2005-02-25 2006-09-14 Johnson Johnnie M Cell-friendly cannula and needle
US20070250158A1 (en) * 2006-04-25 2007-10-25 Medtronic Vascular, Inc. Laminated Implantable Medical Device Having a Metallic Coating
US20080195194A1 (en) * 2007-02-13 2008-08-14 Abbott Cardiovascular Systems Inc. Mri compatible, radiopaque alloys for use in medical devices
US20080206441A1 (en) * 2007-02-27 2008-08-28 Medtronic Vascular, Inc. Ion Beam Etching a Surface of an Implantable Medical Device
US20090209944A1 (en) * 2008-02-14 2009-08-20 Cook Incorporated Component of an implantable medical device comprising an oxide dispersion strengthened (ods) metal alloy
US7691400B2 (en) 2006-05-05 2010-04-06 Medtronic Vascular, Inc. Medical device having coating with zeolite drug reservoirs
US20110200738A1 (en) * 2007-03-28 2011-08-18 Brian Pederson System and Method for Conditioning Implantable Medical Devices

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US5931867A (en) * 1997-04-25 1999-08-03 W.C. Heraeus Gmbh Radially expandable support device
US6387121B1 (en) * 1996-10-21 2002-05-14 Inflow Dynamics Inc. Vascular and endoluminal stents with improved coatings
US6478815B1 (en) * 2000-09-18 2002-11-12 Inflow Dynamics Inc. Vascular and endoluminal stents
US6767360B1 (en) * 2001-02-08 2004-07-27 Inflow Dynamics Inc. Vascular stent with composite structure for magnetic reasonance imaging capabilities
US6790228B2 (en) * 1999-12-23 2004-09-14 Advanced Cardiovascular Systems, Inc. Coating for implantable devices and a method of forming the same
US6845259B2 (en) * 2001-12-26 2005-01-18 Advanced Cardiovascular Systems, Inc. MRI compatible guide wire

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US7101391B2 (en) * 2000-09-18 2006-09-05 Inflow Dynamics Inc. Primarily niobium stent
EP1337286A1 (en) * 2000-11-28 2003-08-27 Fortimedix B.V. Stent
DE10245516B4 (en) * 2002-09-27 2004-09-30 W. C. Heraeus Gmbh & Co. Kg Alloy to be used for stents
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Publication number Priority date Publication date Assignee Title
US5498302A (en) * 1992-02-07 1996-03-12 Smith & Nephew Richards, Inc. Surface hardened biocompatible metallic medical implants
US6387121B1 (en) * 1996-10-21 2002-05-14 Inflow Dynamics Inc. Vascular and endoluminal stents with improved coatings
US5931867A (en) * 1997-04-25 1999-08-03 W.C. Heraeus Gmbh Radially expandable support device
US6790228B2 (en) * 1999-12-23 2004-09-14 Advanced Cardiovascular Systems, Inc. Coating for implantable devices and a method of forming the same
US6478815B1 (en) * 2000-09-18 2002-11-12 Inflow Dynamics Inc. Vascular and endoluminal stents
US6767360B1 (en) * 2001-02-08 2004-07-27 Inflow Dynamics Inc. Vascular stent with composite structure for magnetic reasonance imaging capabilities
US6845259B2 (en) * 2001-12-26 2005-01-18 Advanced Cardiovascular Systems, Inc. MRI compatible guide wire

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20060204535A1 (en) * 2005-02-25 2006-09-14 Johnson Johnnie M Cell-friendly cannula and needle
WO2007098289A2 (en) * 2006-02-27 2007-08-30 Tulip Biomed, Inc. Cell-friendly cannula and needle
WO2007098289A3 (en) * 2006-02-27 2008-07-10 Johnnie M Johnson Cell-friendly cannula and needle
US20070250158A1 (en) * 2006-04-25 2007-10-25 Medtronic Vascular, Inc. Laminated Implantable Medical Device Having a Metallic Coating
US7955383B2 (en) 2006-04-25 2011-06-07 Medtronics Vascular, Inc. Laminated implantable medical device having a metallic coating
US7691400B2 (en) 2006-05-05 2010-04-06 Medtronic Vascular, Inc. Medical device having coating with zeolite drug reservoirs
US20080195194A1 (en) * 2007-02-13 2008-08-14 Abbott Cardiovascular Systems Inc. Mri compatible, radiopaque alloys for use in medical devices
WO2008100852A3 (en) * 2007-02-13 2009-12-03 Abbott Cardiovascular Systems Inc. Mri compatible, radiopaque alloys for use in medical devices
US20080206441A1 (en) * 2007-02-27 2008-08-28 Medtronic Vascular, Inc. Ion Beam Etching a Surface of an Implantable Medical Device
US20110200738A1 (en) * 2007-03-28 2011-08-18 Brian Pederson System and Method for Conditioning Implantable Medical Devices
US8653632B2 (en) * 2007-03-28 2014-02-18 Medtronic Ats Medical Inc. System and method for conditioning implantable medical devices
US20090209944A1 (en) * 2008-02-14 2009-08-20 Cook Incorporated Component of an implantable medical device comprising an oxide dispersion strengthened (ods) metal alloy

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