Coil bioabsorbable stents

• US 9,636,241 B2
• Filed: 08/16/2012
• Issued: 05/02/2017
• Est. Priority Date: 03/30/2012
• Status: Active Grant

• Current Assignee: Manli International Ltd.
• Original Assignee: Manli International Ltd.
• Inventors: Su, Shih-Horng
• Primary Examiner(s): Sevilla, Christian
• Assistant Examiner(s): MILLER, CHERYL L
• Application Number:
  US13/587,219
• Publication Number:
  US 20130261733A1
• Time in Patent Office: 1,720 Days
• Field of Search: 623 122, 623 127, 623 13, 623 131, 623 117
• CPC Class Codes: A61F 2/88 the wire-like elements formed as helical or spiral coils forming a net-like or mesh-like structure A61F2/90
• CPC Class Codes: A61F 2/885 comprising a coil including a plurality of spiral or helical sections with alternate directions around a central axis
• CPC Class Codes: A61F 2/954 for placing stents or stent-grafts in a bifurcation
• CPC Class Codes: A61F 2002/061 provided with means for allowing access to secondary lumens
• CPC Class Codes: A61F 2002/825 having longitudinal struts
• CPC Class Codes: A61F 2210/0004 bioabsorbable
• CPC Class Codes: A61F 2230/0067 conical
• CPC Class Codes: A61F 2230/0091 helically-coiled or spirally-coiled, i.e. having a 2-D spiral cross-section
• CPC Class Codes: A61F 2250/0029 differing in bending or flexure capacity
• CPC Class Codes: A61F 2250/0039 differing in diameter
• CPC Class Codes: A61F 2250/0067 Means for introducing or releasing pharmaceutical products into the body
• CPC Class Codes: A61F 2250/0098 radio-opaque, e.g. radio-opaque markers

Abstract

An expandable, bioabsorbable stent having a coiled-coil configuration is described. The stent further comprises regions of variable pitch that allow for variation in either rigidity, or variability diameter within sub-regions along the length of the deployed stent. By varying the diameter allows the stent to extend into regions such as branched vessels, or into the neck of aneurysms. In some embodiments, the stent comprises longitudinal support fibers that run substantially the length of the deployed stent to provide additional strength. In addition, the stent may also comprise regional support fibers that run less than the length of the stent, and which provide increased regional strength while permitting flexibility of the stent. The stent further comprises micro-tubes that are configured to be visible using medical imaging techniques. The stent can be manufactured from materials that are bioabsorbable and/or include the ability to release pharmacologically active substances over time.

Claims

1. An expandable stent comprising:

a single filament shaped into a primary coil having a plurality of primary coil segments that each include a plurality of elements, the stent having a first diameter when the stent is in a furled configuration;

a plurality of longitudinal support fibers coupled to the filament, wherein at least one longitudinal support fiber is disposed along an outer aspect of the stent and is parallel to a major axis of the stent and extends along the entire length of the stent;

wherein at least one of the elements is expandable beyond others of the elements and arranged such that upon expansion of the elements the stent assumes an unfurled configuration having two distinct diameters at two distinct primary coil segments, and wherein the first diameter is smaller than the two distinct diameters; and

wherein at least another one of the longitudinal support fibers is discontinuous at a location between the two distinct primary coil segments to allow formation of a localized zone of increased radius or curvature along a longitudinal axis of the stent.

2. The expandable stent of claim 1 wherein the plurality of elements are configured as a plurality of secondary coils.

3. The expandable stent of claim 1 wherein each of the primary coil segments comprises at least three elements.

4. The expandable stent of claim 1 wherein at least one element in a first primary coil segment is vertically aligned with at least one element in a second primary coil segment.

5. The expandable stent of claim 1 wherein a further one of the plurality of longitudinal support fibers is continuous at the location between the two distinct primary coil segments.

6. An expandable stent comprising:

a single filament shaped into a primary coil having a plurality of primary coil segments that each include a plurality of elements having a decreased radius of curvature in a furled configuration compared to a radius of curvature of the elements in an unfurled configuration;

wherein the filament comprises a bioabsorbable polymer;

a first longitudinal support fiber disposed along an outer aspect of the stent and is parallel to a major axis of the stent and extends across at least two primary coil segments to thereby increase stability of the stent, and wherein the first longitudinal support fiber extends along the entire length of the stent;

a first regional support fiber extending only along a portion of the length of the stent and configured to allow formation of a localized zone of increased radius or curvature along a longitudinal axis of the stent.

7. The expandable stent of claim 6 further comprising a second regional support fiber, and wherein the first regional support fiber and the second regional support fiber are lying along a common axis and longitudinally spaced from one another.

8. The expandable stent of claim 7 wherein a first primary coil segment has a radius of curvature that is different from a second primary coil segment, and wherein a transition from the first to the second primary coil segment is located at a location between the first and second regional support fibers.

9. The expandable stent of claim 6 wherein a first primary coil segment has a radius of curvature that is different from a second primary coil segment.

10. An expandable stent comprising:

a single filament shaped into a primary coil having a plurality of primary coil segments and first and second sets of secondary coil segments, wherein the first and second sets of secondary coil segments are disposed within each of the primary coil segments;

wherein the filament comprises a bioabsorbable polymer;

a plurality of longitudinal support fibers coupled to the filament, wherein at least one longitudinal support fiber is disposed along an outer aspect of the stent and is parallel to a major axis of the stent and extends across at least two primary coil segments;

wherein the stent has a first stent diameter when the stent is in a furled configuration;

wherein at least one secondary coil segment of the first set of secondary coil segments has a first coil diameter, and wherein the second set of secondary coil segments has a second coil diameter, wherein the first coil diameter is larger than the second coil diameter;

wherein the first and second sets of secondary coil segments are configured such that, when the stent in an unfurled configuration, the stent has a second stent diameter and a third stent diameter, wherein the second and third stent diameters are larger than the first stent diameter, and wherein the second stent diameter is larger than the third stent diameter; and

wherein at least one of the longitudinal support fibers is configured to allow localized flexing of the stent about a longitudinal axis of another of the longitudinal support fibers.

11. The expandable stent of claim 10 wherein a first set of the plurality of primary coil segments have a first helical pitch angle, wherein a second set of the plurality of primary coil segments have a second helical pitch angle, and wherein first and second helical pitch angles are different.

12. The expandable stent of claim 10 wherein the at least one of the longitudinal support fibers is discontinuous at a location of the second stent diameter.

13. The expandable stent of claim 10 wherein the stent is configured such that the second stent diameter is located where the first set of secondary coil segments is unfurled.

14. The expandable stent of claim 10 further comprising a radio-opaque label.

15. The expandable stent of claim 10 wherein the first set of the secondary coil segments are vertically aligned relative to each other.