# US 10,478,323 B2 · Biodegradable stent and shape memory expanding method therefor

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- Number: US 10,478,323 B2
- Document ID: US10478323B2
- Status: Granted
- Kind: B2
- Application number: 15/329,957
- Filed: 2015-12-08
- Published: 2017-09-21
- Granted: 2019-11-19
- Earliest claimed: 2014-12-08
- Assignees: Suntech, Inc.
- Applicants: Suntech Co., Ltd.
- Inventors: Hyungil Kim; Hyun Hee Han
- Web page: https://patentgrep.com/patent/US10478323B2

## CPC

- A61F 2/958: Inflatable balloons for placing stents or stent-grafts
- A61F 2/91: made from perforated sheets or tubes, e.g. perforated by laser cuts or etched holes
- A61L 31/06: obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds {(A61L31/041 takes precedence)}
- A61L 31/14: Materials characterised by their function or physical properties {, e.g. injectable or lubricating compositions, shape-memory materials, surface modified materials}
- A61L 31/148: {Materials at least partially resorbable by the body}
- A61L 31/16: Biologically active materials, e.g. therapeutic substances {(A61L31/047 takes precedence)}
- A61F 2/9522: {Means for mounting a stent or stent-graft onto or into a placement instrument}
- A61F 2210/0004: bioabsorbable
- A61F 2210/0014: using shape memory or superelastic materials, e.g. nitinol
- A61L 2400/16: Materials with shape-memory or superelastic properties
- 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)

## Abstract

The present invention relates to a biodegradable stent and a shape memory extending method thereof. According to an exemplary embodiment of the present invention, radial force of a biodegradable stent may be largely increased through the shape memory extending method of the biodegradable stent and the number of cracks may be decreased after crimping and stent inflation.

## Claims

### Claim 1

A shape memory extending method of a biodegradable stent, comprising:
providing a stent made of a biodegradable polymer on an external surface of a balloon of a first balloon catheter;
extending an outer diameter of the stent by applying a first pressure to the balloon of the first balloon catheter to produce a stent with an extended outer diameter;
providing the stent with the extended outer diameter on an external surface of a balloon of a second balloon catheter; and
reducing the extended outer diameter of the stent, by crimping the stent while applying a second pressure to the balloon of the second balloon catheter;
wherein the step of extending the outer diameter of the stent is conducted at a temperature range of 55 to 180° C.; and
wherein the second balloon catheter is provided in crimping equipment.

### Claim 2 (depends on 1)

The shape memory extending method of a biodegradable stent of claim 1, wherein each of the first balloon catheter and the second balloon catheter is independently provided in crimping equipment.

### Claim 3 (depends on 1)

The shape memory extending method of a biodegradable stent of claim 1, wherein the stent made of the biodegradable polymer is a stent acquired by laser-cutting a biodegradable polymer tube.

### Claim 4 (depends on 1)

The shape memory extending method of a biodegradable stent of claim 1, wherein each of the first balloon catheter and the second balloon catheter is independently a compliant balloon catheter or semi-compliant balloon catheter.

### Claim 5 (depends on 4)

The shape memory extending method of a biodegradable stent of claim 4, wherein the first balloon catheter is the compliant balloon catheter and the second balloon catheter is the semi-compliant balloon catheter.

### Claim 6 (depends on 5)

The shape memory extending method of a biodegradable stent of claim 5, wherein the first balloon catheter is the compliant balloon catheter in which a balloon is not folded or the second balloon catheter is the semi-compliant balloon catheter in which the balloon is folded.

### Claim 7 (depends on 1)

The shape memory extending method of a biodegradable stent of claim 1, wherein the step of reducing the extended outer diameter of the stent is conducted at a temperature range of 37 to 80° C.

### Claim 8 (depends on 1)

The shape memory extending method of a biodegradable stent of claim 1, wherein the first pressure and the second pressure is each independently in the range of 1 to 350 psi (0.06 to 23.8 atm).

### Claim 9 (depends on 1)

The shape memory extending method of a biodegradable stent of claim 1, wherein the biodegradable polymer is selected from the group consisting of polyglycolide, polylactide, poly p-dioxanone, polycaprolactone, trimethylene carbonate, polyhydroxyalkanoates, polypropylene fumarate, polyortho esters, polyester, polyanhydride, polyphosphazenes, polyalkylcianoacrylatepoloxamers, polyamino L-tyrosine, modified polysaccharides, oxidized cellulose, gelatin, and collagen.

### Claim 10 (depends on 1)

The shape memory extending method of a biodegradable stent of claim 1, wherein in the extending of the outer diameter of the stent, the outer diameter of the stent is changed by 105 to 500% based on the outer diameter of an initial stent.

### Claim 11 (depends on 1)

The shape memory extending method of a biodegradable stent of claim 1, wherein in the reducing of the extended outer diameter of the stent, the outer diameter of the stent is changed by 10 to 50% based on the outer diameter of the stent which is maximally enlarged.