Biodegradable stent and shape memory expanding method therefor
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.
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.
2. 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.
3. 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.
4. 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.
5. 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.
6. 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.
7. 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.
8. 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).
9. 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.
10. 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.
11. 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.