# US 2014/0155979 A1 · Preferentially Electropolished Stent System and Method of Manufacture

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- Number: US 2014/0155979 A1
- Document ID: US20140155979A1
- Status: Published application
- Kind: A1
- Application number: 13/705,842
- Filed: 2012-12-05
- Published: 2014-06-05
- Earliest claimed: 2012-12-05
- Assignees: Medtronic Vascular, Inc.
- Applicants: Medtronic Vascular, Inc.
- Inventors: Rui Lam; Dustin Thompson
- Web page: https://patentgrep.com/patent/US20140155979A1

## 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)
- C25F 3/16: Polishing
- A61F 2240/001: Designing or manufacturing processes
- A61F 2250/0025: differing in roughness
- 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)
- C25F: PROCESSES FOR THE ELECTROLYTIC REMOVAL OF MATERIALS FROM OBJECTS; APPARATUS THEREFOR

## Abstract

The preferentially electropolished stent system and method of manufacture includes a stent delivery system including a catheter; a balloon operably attached to the catheter; and a stent disposed on the balloon. The stent includes an elongate body having an abluminal surface and a luminal surface; wherein the abluminal surface has an abluminal average roughness less than or equal to 0.030 microns; and the luminal surface has at least one rough portion having an luminal average roughness greater than or equal to 0.036 microns.

## Claims

### Claim 1

A stent delivery system comprising:
a catheter;
a balloon operably attached to the catheter; and
a stent disposed on the balloon;
wherein the stent comprises:
an elongate body having an abluminal surface and a luminal surface;
wherein the abluminal surface has an abluminal average roughness less than or equal to 0.030 microns; and
the luminal surface has at least one rough portion having an luminal average roughness greater than or equal to 0.036 microns.

### Claim 2 (depends on 1)

The stent delivery system of claim 1 wherein the rough portion completely covers the luminal surface.

### Claim 3 (depends on 1)

The stent delivery system of claim 1 wherein the elongate body comprises a single wire having a circumference and being formed into the stent, the rough portion covering 90 degrees of the circumference on the luminal surface.

### Claim 4 (depends on 1)

The stent delivery system of claim 1 wherein the rough portion comprises axial stripes on the luminal surface.

### Claim 5 (depends on 1)

The stent delivery system of claim 1 wherein the rough portion comprises radial bands on the luminal surface.

### Claim 6 (depends on 1)

The stent delivery system of claim 1 wherein the luminal average roughness is selected to provide a retention force of greater than 255 grams and the abluminal average roughness is selected to provide a tracking force of less than 55.5 grams.

### Claim 7 (depends on 1)

The stent delivery system of claim 1 wherein the abluminal average roughness is 0.026±0.004 microns and the luminal average roughness is 0.046±0.010 microns.

### Claim 8 (depends on 1)

The stent delivery system of claim 1 wherein the luminal average roughness exceeds the abluminal average roughness by greater than or equal to 0.020 microns.

### Claim 9 (depends on 1)

The stent delivery system of claim 1 wherein the stent is selected from the group consisting of a continuous sinusoidal stent, a modular stent, and a laser cut stent.

### Claim 10

A stent comprising:
an elongate body having an abluminal surface and a luminal surface;
wherein the abluminal surface has an abluminal average roughness less than or equal to 0.030 microns; and
the luminal surface has at least one rough portion having a roughness an luminal average roughness greater than or equal to 0.036 microns.

### Claim 11 (depends on 10)

The stent of claim 10 wherein the rough portion completely covers the luminal surface.

### Claim 12 (depends on 10)

The stent of claim 10 wherein the elongate body comprises a single wire having a circumference and being formed into the stent, the rough portion covering 90 degrees of the circumference on the luminal surface.

### Claim 13 (depends on 10)

The stent of claim 10 wherein the rough portion comprises axial stripes on the luminal surface.

### Claim 14 (depends on 10)

The stent of claim 10 wherein the rough portion comprises radial bands on the luminal surface.

### Claim 15 (depends on 10)

The stent of claim 10 wherein the luminal average roughness is selected to provide a retention force of greater than 255 grams and the abluminal average roughness is selected to provide a tracking force of less than 55.5 grams.

### Claim 16 (depends on 10)

The stent of claim 10 wherein the abluminal average roughness is 0.026±0.004 microns and the luminal average roughness is 0.046±0.010 microns.

### Claim 17 (depends on 10)

The stent of claim 10 wherein the luminal average roughness exceeds the abluminal average roughness by greater than or equal to 0.020 microns.

### Claim 18 (depends on 10)

The stent of claim 10 wherein the stent is selected from the group consisting of a continuous sinusoidal stent, a modular stent, and a laser cut stent.

### Claim 19

A method of manufacturing a stent comprising:
providing an electropolishing apparatus having a DC source, an electrolyte bath, and an electrode, the DC source having a positive terminal and a negative terminal, the negative terminal being operably connected to the electrode, the electrode being located in the electrolyte bath;
preparing a rough stent for electropolishing;
operably connecting the rough stent to the positive terminal of the DC source, the rough stent having an abluminal surface and a luminal surface;
placing the rough stent in the electrolyte bath;
operating the electropolishing apparatus to preferentially remove surface material from the abluminal surface without removing surface material from at least a portion of the luminal surface to electropolish the abluminal surface while maintaining surface roughness on the at least a portion of the luminal surface to produce the stent.

### Claim 20 (depends on 19)

The method of claim 19 wherein the preparing comprises applying a contact mask to the portion of the luminal surface, and the method further comprises removing the contact mask after the operating.

### Claim 21 (depends on 19)

The method of claim 19 wherein the preparing comprises fixing the rough stent on a mandrel in contact with the portion of the luminal surface, and the method further comprises removing the mandrel from the stent after the operating.

### Claim 22 (depends on 21)

The method of claim 21 wherein the mandrel is in contact with the portion of the luminal surface along axial stripes.

### Claim 23 (depends on 21)

The method of claim 21 the mandrel is in contact with the portion of the luminal surface along radial bands.

### Claim 24 (depends on 19)

The method of claim 19 wherein the preparing comprises placing a flow reducer interior to the luminal surface, the operating comprises generating axial electrolyte flow past the stent, and the method further comprises removing the flow reducer from the stent after the operating.

### Claim 25 (depends on 19)

The method of claim 19 wherein the operating comprises generating greater axial electrolyte flow past the abluminal surface then the luminal surface.

### Claim 26 (depends on 19)

The method of claim 19 wherein the operating comprises electropolishing the abluminal surface to an abluminal average roughness less than or equal to 0.030 microns.

### Claim 27 (depends on 26)

The method of claim 26 wherein the abluminal average roughness is 0.026±0.004 microns.

### Claim 28 (depends on 19)

The method of claim 19 wherein the at least a portion of the luminal surface has a luminal average roughness greater than or equal to 0.036 microns.

### Claim 29 (depends on 28)

The method of claim 28 wherein the luminal average roughness is 0.046±0.010 microns.

### Claim 30 (depends on 19)

The method of claim 19 wherein the operating comprises electropolishing the abluminal surface so that luminal average roughness exceeds abluminal average roughness by greater than or equal to 0.020 microns.