# US 8,769,794 B2 · Specially configured and surface modified medical device with certain design features that utilize the intrinsic properties of tungsten, zirconium, tantalum and/or niobium

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- Number: US 8,769,794 B2
- Document ID: US8769794B2
- Status: Granted
- Kind: B2
- Application number: 12/441,213
- Filed: 2007-09-21
- Published: 2010-12-02
- Granted: 2014-07-08
- Earliest claimed: 2006-09-21
- Assignees: MICO Innovations, LLC
- Applicants: Joseph G. Furst
- Inventors: Joseph G. Furst
- Web page: https://patentgrep.com/patent/US8769794B2

## CPC

- A61L 31/022: {Metals or alloys}
- A61F 2/91: made from perforated sheets or tubes, e.g. perforated by laser cuts or etched holes
- A61F 2/915: with bands having a meander structure, adjacent bands being connected to each other
- A61L 29/02: Inorganic materials
- A61F 2/88: the wire-like elements formed as helical or spiral coils
- A61F 2002/91508: {the meander having a difference in amplitude along the band}
- A61F 2002/9155: {Adjacent bands being connected to each other}
- A61F 2002/91558: {connected peak to peak}
- A61F 2002/91575: {connected peak to trough}
- A61F 2250/0036: differing in thickness
- A61F 2250/0039: differing in diameter
- Y10T 29/49885: with coating before or during assembling
- Y10T 29/49996: Successive distinct removal operations
- 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)
- 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)
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

Medical devices having special geometrical design features and possible surface modifications and can be comprised of niobium, tantalum, zirconium and/or tungsten alloy which is useful in treating a body passageway.

## Claims

### Claim 1

A process for producing a stent that has design features that include differentiated wall thicknesses across the length of the stent and geometrically-based shapes to enhance the mechanical properties of said stent, said process comprising the steps of:
a) providing a non-clad metal tube, about 100 weight percent of said metal tube formed of an alloy of 90-97.5% tantalum and 2.5-10% tungsten, said metal having a grain size of at least about 8 ASTM;
b) chemically cleaning said metal tube by a solution that includes nitric acid and hydrochloric acid;
c) annealing said chemically cleaned tube at a temperature of about 2600° F.-2800° F., said step of annealing occurring under a vacuum of no greater that about 10 Torr;
d) cleaning and polishing said annealed tube by an electro-polishing process, said electro-polishing process including a solution that includes sulfuric acid and hydrofluoric acid having a temperature of about 60-100° F., said electro-polishing process conducted in the presence of a current of 15-30 milliamps, said step of electro-polishing performed in such a manner as to prevent said metal tube from becoming brittle and to prevent excess hydrogen, oxygen and nitrogen from entering said metal tube;
e) cutting said tube to a desired length after said cleaning and polishing step; and,
f) cutting said tube to form said stent after said tube is cut to said desired length, said step of cutting said tube into said stent includes a laser cutting process in an environment that includes one or more gasses selected from the group consisting of helium and argon, said stent having a plurality of metal support portions and a plurality of metal connecting legs, said metal connecting legs connecting together a plurality of metal support portions, said metal support portions and metal connecting legs forming a mesh in a peripheral wall of said cut tube, a plurality of said metal support portions having an S-shape, a Z-shape, an XZ-shape, a VU shape, an XS shape, or a YU-shape configuration, a plurality of said metal support portions having a thickness of 0.0012-0.007 inch, a plurality of said metal support portions and connecting legs having multiple thicknesses along a longitudinal length of said metal support portions and connecting legs, a thinnest portion of said metal support portions having a thickness as small as about 0.0012 inch and a thickest portion of said metal support portions being about 0.004-0.007 inch, said wall thickness of said metal tube has a thickness so that its physiological presence in a body passage is negligible thereby preventing turbulent flow of fluid as the fluid passes by said stent positioned in the body passageway.

### Claim 2 (depends on 1)

The process as defined in claim 1, wherein said metal includes 90-93% tantalum and 7-10% tungsten.

### Claim 3 (depends on 2)

The process as defined in claim 2, wherein said metal includes 92.5 wt. % tantalum and 7.5 wt. % tungsten.

### Claim 4 (depends on 1)

The process as defined in claim 1, including the further step of forming a plurality of surface modifications in one or more structures selected from the group consisting of metal support portions and metal connecting legs, said surface modifications including a channel, said channel having a single opening at only one end of said channel, said single opening located at a surface of said stent.

### Claim 5 (depends on 3)

The process as defined in claim 3, including the further step of forming a plurality of surface modifications in one or more structures selected from the group consisting of metal support portions and metal connecting legs, said surface modifications including a channel, said channel having a single opening at only one end of said channel, said single opening located at a surface of said stent.

### Claim 6 (depends on 4)

The process as defined in claim 4, including the further step of adding at least one of a polymer and a biological agent to one or more structures selected from the group consisting of metal support portions and metal connecting legs, a plurality of said channels including said biological agent, at least one of said channels including at least one of a polymer and a biological agent.

### Claim 7 (depends on 5)

The process as defined in claim 5, including the further step of adding at least one of a polymer and a biological agent to one or more structures selected from the group consisting of metal support portions and metal connecting legs, a plurality of said channels including said biological agent, at least one of said channels including at least one of a polymer and a biological agent.

### Claim 8 (depends on 6)

The process as defined in claim 6, wherein said polymer overlies a plurality of said channels that includes said biological agent so as to control a release rate of said biological agent from said plurality of channels.

### Claim 9 (depends on 7)

The process as defined in claim 7, wherein said polymer overlies a plurality of said channels that includes said biological agent so as to control a release rate of said biological agent from said plurality of channels.

### Claim 10

A process for producing a stent that has design features that include differentiated wall thicknesses across the length of the stent and geometrically-based shapes to enhance the mechanical properties of said stent, said process comprising the steps of:
a) providing a non-clad metal tube, about 100 weight percent of said metal tube formed of an alloy of 90-93% tantalum and 7-10% tungsten, said metal having a grain size of at least about 8 ASTM;
b) chemically cleaning said metal tube by a solution that includes nitric acid and hydrochloric acid;
c) annealing said chemically cleaned tube at a temperature of about 2600° F.-2800° F., said step of annealing occurring under a vacuum of no greater that about 10 Torr;
d) cleaning and polishing said annealed tube by an electro-polishing process, said electro-polishing process including a solution that includes sulfuric acid and hydrofluoric acid having a temperature of about 60-100° F., said electro-polishing process conducted in the presence of a current of 15-30 milliamps, said step of electro-polishing performed in such a manner as to prevent said metal tube from becoming brittle and to prevent excess hydrogen, oxygen and nitrogen from entering said metal tube;
e) cutting said tube to a desired length after said cleaning and polishing step; and,
f) cutting said tube to form said stent after said tube is cut to said desired length, said step of cutting said tube into said stent includes a laser cutting process in an environment that includes one or more gasses selected from the group consisting of helium and argon, said stent having a plurality of metal support portions and a plurality of metal connecting legs, said metal connecting legs connecting together a plurality of metal support portions, said metal support portions and metal connecting legs forming a mesh in a peripheral wall of said cut tube, a plurality of said metal support portions having a thickness of 0.0012-0.007 inch, a plurality of said metal support portions and connecting legs having multiple thicknesses along a longitudinal length of said metal support portions and connecting legs, a thinnest portion of said metal support portions having a thickness as small as about 0.0012 inch and a thickest portion of said metal support portions being about 0.004-0.007 inch, said wall thickness of said metal tube has a thickness so that its physiological presence in a body passage is negligible thereby preventing turbulent flow of fluid as the fluid passes by said stent positioned in the body passageway.