Biodegradable stent and shape memory expanding method therefor
Inventors
Assignees
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Publication Number
US-10478323-B2
Publication Date
2019-11-19
Expiration Date
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.
Core Innovation
A biodegradable stent is provided in a shape memory extending method in which the biodegradable polymer stent is placed on an external surface of a balloon of a first balloon catheter. The outer diameter of the stent is extended by applying a first pressure to the balloon of the first balloon catheter to produce a stent with an extended outer diameter, and the stent with the extended outer diameter is then provided on an external surface of a balloon of a second balloon catheter.
The extended outer diameter is reduced by crimping the stent while applying a second pressure to the balloon of the second balloon catheter. The extending step of the outer diameter is conducted at a temperature range of 55 to 180°C, and the second balloon catheter is provided in crimping equipment. The method is described for biodegradable stents with increased stent radial force and reduced crack formation after crimping/inflation.
The method is described with balloon compliance types and balloon structure constraints, including non-compliant, semi-compliant, and compliant balloons, and folded versus not folded balloon configurations. Example embodiments include semi-compliant balloon (nylon) and compliant balloons (nylon and polyurethane), together with laser-cut biodegradable polymer tube stent fabrication context.
Claims Coverage
The patent includes one independent claim directed to a shape memory extending method for a biodegradable stent. The dependent claims refine the independent claim by constraining the amount of outer-diameter change, specifying temperature ranges for the reduction step, constraining first and second pressures, and narrowing balloon catheter structure using compliant versus semi-compliant and folded versus not folded configurations, as well as specifying biodegradable polymer materials and stent formation context.
Shape memory extending method for a biodegradable stent using first and second balloon catheters with crimping
Providing a biodegradable polymer stent 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 extending is conducted at a temperature range of 55 to 180°C and the second balloon catheter is provided in crimping equipment.
The inventive focus is the two-balloon-catheter approach for extending outer diameter at 55 to 180°C followed by reduction by crimping using the second balloon catheter in crimping equipment, with further constraints on the extent of outer-diameter change, balloon type, and biodegradable polymer materials.
Stated Advantages
Increases stent radial force.
Reduces crack formation after crimping/inflation.
Documented Applications
Use in shape memory extending of a biodegradable stent to achieve increased radial force and reduced cracking after crimping/inflation, including embodiments associated with stent fabrication from a laser-cut biodegradable polymer tube.
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