Method of making a stent

Patent metadata

Field	Value
Publication number	US-9867728-B2
Application number	US-201514881073-A
Country	US
Kind code	B2
Filing date	Oct 12, 2015
Priority date	Jan 30, 2010
Publication date	Jan 16, 2018
Grant date	Jan 16, 2018

Abstract

A method of manufacturing a stent is disclosed. The stent includes a minimum crimped diameter such that in the minimum crimped diameter, a pair of stent rings, between which marker support structures reside, do not make contact with the marker support structures. The crimped profile of the stent of the present invention can be as small as the crimped profile of a same stent but without the marker support structures.

First claim

The invention claimed is:

1. A method for making a medical device, comprising:
(a) providing a polymeric tube;
(b) cutting a pattern into the tube by a laser, wherein the pattern includes:
(i) a set of rings including a proximal end ring, a distal end ring opposing the proximal end ring, and middle rings positioned between the end rings, wherein each ring is associated with its direct neighboring ring by links, and wherein at least one pair of neighboring middle rings can be delineated, via corresponding links there between, into closed cells comprising a W-V shaped zone;
(ii) the rings include struts and crowns, the struts fold towards and unfold away from each other at the crowns;
(iii) at least one of the links being a marker link, the marker link having a first structure off a first side wall of the marker link for holding a first marker and a second structure off a second, opposite side wall of the marker link for holding a second marker, wherein the first and second structures are not longitudinally off-set from one another off of the marker link; and
(iv) wherein the polymeric tube is cut by the laser such that the set of rings and links are shaped to have a minimum crimped diameter such that in the minimum crimped diameter, a pair of rings, between which the marker link resides, do not make contact with the first and second structures;

and
(c) placing the first and second markers in the structures and forming a stent; and
(d) crimping the stent to a crimped diameter on a section of a catheter delivery assembly, such that the pair of rings, between which the marker link resides, do not make contact with the first and second structures in the crimped diameter, whereby a medical device comprising the stent and catheter is produced.

2. The method of claim 1 , wherein the diameter of the tube is greater than an expanded diameter of the stent when implanted in a lumen.

3. The method of claim 1 , wherein the crimping act includes a heating step of heating the stent to a temperature below the glass transition temperature of a polymer of the stent.

4. The method of claim 1 , wherein the minimum crimped diameter is less than the crimped diameter.

5. The method of claim 1 , wherein the stent is crimped on a balloon of the catheter assembly.

6. The method of claim 1 ,
wherein each link adjoins a pair of the neighboring rings at a crown of each ring, and
wherein the minimum crimped diameter (MCD) is equal to the value derived from equation 1 or equation 2:
MCD=(Σ Swi+ΣCrj+ΣLwk )*(π)−1+2*WT  (equation 1)

MCD=(Σ Swi+ΣCrj+ΣLwk )*(π)−1  (equation 2)

such that
ΣSwi (i=1 . . . n) is the sum of n ring struts having width Swi;
ΣCrj (j=1 . . . m) is the sum of m crown inner radii having radii Crj (times 2);
ΣLwk (k=1 . . . p) is the sum of p links having width Lwk; and
WT is a ring wall thickness.

7. The method of claim 6 , wherein each strut has an aspect ratio (AR) of 0.8 to 1.4, AR being defined as ratio of width to thickness, and wherein each link has an AR of 0.4 to 0.9.

8. The method of claim 1 ,
wherein each link adjoins a pair of the neighboring rings at a crown of each ring, and
wherein the minimum crimped diameter (MCD) is less than the value derived from equation 1 or equation 2:
MCD=(Σ Swi+ΣCrj+ΣLwk )*(π)−1+2*WT  (equation 1)

MCD=(Σ Swi+ΣCrj+ΣLwk )*(π)−1  (equation 2)

such that
ΣSwi (1=1 . . . n) is the sum of n ring struts having width Swi;
ΣCrj (j=1 . . . m) is the sum of m crown inner radii having radii Crj (times 2);
ΣLwk (k=1 . . . p) is the sum of p links having width Lwk; and
WT is a ring wall thickness.

9. The method of claim 8 , wherein each strut has an aspect ratio (AR) of 0.8 to 1.4, AR being defined as ratio of width to thickness, and wherein each link has an AR of 0.4 to 0.9.

10. The method of claim 1 , wherein the marker link is longer than the links which do not have a marker.

11. The method of claim 1 , wherein a pre-crimped crown angle is greater than a deployment crown angle.

12. The method of claim 1 , wherein the first structure and the second structure including the first and second markers are circumferentially off-set from the marker link and spaced from the pair of rings associated with the marker link.

13. The method of claim 1 ,
wherein at least one pair of the neighboring middle rings is adjoined by middle links, each middle link is associated with one crown of one ring and another crown of the neighboring ring, such that each middle link and its corresponding crown for the one ring forms a generally “Y” shaped structure and each middle link and its corresponding crown for the neighboring ring forms a generally “W” shaped structure.

14. The method of claim 1 , wherein at least one of the middle rings has undulated segments and a repeating pattern of “Y” shaped and “W” shaped constructions where the undulated segments meet the links, and wherein the pattern further includes an undulated segment that is link-free between each “Y” and “W” shaped construction.

15. The method of claim 1 , wherein the minimum crimped diameter is an inner diameter of the stent when the following step is performed: bending the struts of the rings towards each other, wherein the struts bend at the crowns, such that after bending, at least one of a pair of struts adjoined by a crown is separated by a distance of about zero or the at least one pair of struts is touching each other.

16. The method of claim 1 , wherein the marker link and two strut segments of a ring associated with the marker link form a “Y” shaped segment.

17. The method of claim 1 , wherein the set of rings comprises a first ring, a second ring, and a third ring, the second ring being positioned between the first and third rings, wherein the links residing between the first ring and the second ring are circumferentially off-set from the links residing between the second ring and the third ring.

18. The method of claim 1 , wherein at least one of the struts has an aspect ratio (AR) of 0.8 to 1.4, and wherein at least one of the links has an aspect ratio of (AR) 0.4 to 0.9, AR being defined as ratio of width to thickness.

19. The method of claim 1 , wherein each of the closed cells consists of 8 link-free crowns.

20. The method of claim 1 , wherein the at least one pair of neighboring middle rings forms only 3 W-V shaped closed cells.

21. The method of claim 1 , wherein the set of rings comprises a first ring, a second ring, and a third ring, the second ring being positioned between the first and third rings, and
wherein the first and second rings, including the links there between, define a first set of W-V shaped closed cells,
wherein the second and third rings, including the links there between, define a second set of W-V shaped closed cells, and
wherein the W-V shaped closed cells of the first set are circumferentially off-set from the W-V shaped closed cells of the second set.

22. The method of claim 1 , wherein at least some of the middle rings have a repeating pattern of “Y” shaped and “W” shaped crowns where the rings meet the links, and
wherein the pattern further includes a pattern of one and three link-free crowns between the “Y” and “W” shaped crowns.

23. The method of claim 1 , wherein the links between a first pair of rings are out of phase or circumferentially off-set from the links between a second pair of rings, the first pair of rings and the second pair of rings sharing a common interior ring; a

Assignees

• Abbott Cardiovascular Systems Inc

Inventors

• Trollsas Mikael
• Ngo Michael H
• Anukhin Boris
• Nikanorov Alexander
• Hossainy Syed
• Papp John E
• Jayasinghe Dudley
• Solter Zella

Classifications

• A61F2210/0019

  operated at only one temperature whilst inside or touching the human body, e.g. constrained in a non-operative shape during surgery, another temperature only occurring before the operation · CPC title

• A61F2210/0014

  using shape memory or superelastic materials, e.g. nitinol · CPC title

• A61F2002/91558

  connected peak to peak · CPC title

• A61F2250/0098

  radio-opaque, e.g. radio-opaque markers · CPC title

• A61F2/82

  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) · CPC title