Ultraflexible open cell stent

• US 6,540,775 B1
• Filed: 06/30/2000
• Issued: 04/01/2003
• Est. Priority Date: 06/30/2000
• Status: Expired due to Term

• Current Assignee: Cardinal Health Switzerland 515 GmbH (Cardinal Health, Inc.)
• Original Assignee: Cordis Corporation (Cardinal Health, Inc.)
• Inventors: Fischell, David R., Fischell, Robert E., Fischell, Tim A.
• Primary Examiner(s): Milano, Michael J.
• Assistant Examiner(s): Ho, Tan-Uyen T.
• Application Number:
  US09/607,980
• Time in Patent Office: 1,005 Days
• Field of Search: 623/1-5-, 623/1.1, 623/1.36, 623/1.25, 623/900, 623/901, 606/194, 606/195, 606/200
• US Class Current: 623/1.15
• CPC Class Codes: A61F 2/91 made from perforated sheet material or tubes, e.g. perforated by laser cuts or etched holes
• CPC Class Codes: A61F 2/915 with bands having a meander structure, adjacent bands being connected to each other
• CPC Class Codes: A61F 2002/91508 the meander having a difference in amplitude along the band
• CPC Class Codes: A61F 2002/91516 the meander having a change in frequency along the band
• CPC Class Codes: A61F 2002/91525 within the whole structure different bands showing different meander characteristics, e.g. frequency or amplitude
• CPC Class Codes: A61F 2002/91533 characterised by the phase between adjacent bands
• CPC Class Codes: A61F 2002/91541 Adjacent bands are arranged out of phase
• CPC Class Codes: A61F 2002/91558 connected peak to peak
• CPC Class Codes: A61F 2002/91575 connected peak to trough
• CPC Class Codes: A61F 2002/91583 by a bridge, whereby at least one of its ends is connected along the length of a strut between two consecutive apices within a band

Abstract

Disclosed is an open cell stent that has adjacent sets of circumferential struts connected by means of highly flexible, undulating, connecting struts. To decrease outward flaring of the circumferential struts when the pre-deployed stent is advanced through highly curved vessels, each unconnected strut of the sets of circumferential struts has a decreased longitudinal length as compared to the longitudinal length of the circumferential struts that are connected by the flexible connecting struts. To decrease the propensity for outward flaring of the end set of circumferential struts, the longitudinal length of the end set of circumferential struts is shorter than the longitudinal length of the interior set of circumferential struts. Also, the attachment point of the flexible connecting struts is off the center of the curved sections of the circumferential struts, thus also decreasing the tendency for outward flaring of the end set of circumferential struts.

Claims

1. A stent in the form of a thin-walled, lace-like, cylindrical tube with a longitudinal axis, the stent comprising:

a multiplicity of interior circumferential sets of strut members and one end circumferential set of strut members at each of the two longitudinal ends of the stent;

each interior circumferential set of strut members including at least one connected strut member consisting of a long diagonal section having a longitudinal length L1 fixedly attached to a connected curved section, each connected curved section being joined by means of a longitudinal connecting link to one connected curved section of an adjacent circumferential set of strut members and all connecting links that connect adjacent circumferential sets of strut members are connected at a connected curved section;

each interior set of strut members also including at least one unconnected strut member consisting of a short diagonal section having a longitudinal length L2 fixedly joined to an unconnected curved section; and

the stent being further characterized by having the length L1 of each long diagnol section being longer than the length L2 of each short diagonal section i.e.;

L1<

L2, so that the unconnected strut members have a decreased tendency for flaring outward as the stent is advanced though a curved vessel.

2. The stent of claim 1 wherein the longitudinal connecting link is straight.

3. The stent of claim 1 wherein the longitudinal connecting link is an undulating, flexible, longitudinal connecting link that is adapted to change its length in the longitudinal direction as the stent is advanced through a curved vessel.

4. The stent of claim 3 wherein the place where each flexible longitudinal connecting link is joined to the interior set of strut members is near the connecting line where a connected curved section is joined to a diagonal section.

5. The stent of claim 3 wherein the flexible connecting link is in the general form of an “

S”

.

6. The stent of claim 3 wherein upon deployment to its deployed state, the flexible longitudinal connecting links extend in their longitudinal length thereby reducing the foreshortening of the stent.

7. The stent of claim 1 wherein there are at most three longitudinal connecting links that join each adjacent pair of circumferential sets of strut members.

8. The stent of claim 1 wherein there are at most five longitudinal connecting links that join each adjacent pair of circumferential sets of strut members.

9. The stent of claim 1 wherein there are at most eight longitudinal connecting links that join each adjacent pair of circumferential sets of strut members.

10. The stent of claim 1 wherein the total longitudinal length L4 in the longitudinal direction of each end circumferential set of strut members is shorter than the longitudinal length L3 in the longitudinal direction of each interior circumferential set of strut members, thus decreasing the propensity for flaring outward of the end circumferential set of strut members when the pre-deployed stent is advanced through a curved vessel.

11. The stent of claim 1 wherein the metal from which the stent is formed in stainless steel and the wall thickness of the pre-deployed stent is greater than 0.0045 inches so as to obtain acceptable radiopacity for the stent when it is being implanted into a human subject.

12. The stent of claim 1 wherein the metal from which the stent is formed is tantalum and the wall thickness of the pre-deployed stent is greater than 0.002 inches so as to obtain acceptable radiopacity for the stent when it is being implanted into a human subject.

13. The stent of claim 1 wherein the metals from which the stent is formed is a sandwich of three coaxial tubes having stainless steel as interior and exterior tubes and a central tube formed from a high density metal, the total wall thickness of the pre-deployed stent being greater than 0.003 inches so as to obtain acceptable radiopacity for the stent when it is being implanted into a human subject.

14. A stent in the form of a thin-walled, lace-like, cylindrical tube with a longitudinal axis, the stent comprising:

a multiplicity of interior circumferential sets of strut members and one end circumferential set of strut members at each of the two longitudinal ends of the stent;

each interior circumferential set of strut members including at least one connected strut member consisting of a long diagonal section having a longitudinal length L1 fixedly attached to a connected curved section, each connected curved section of an adjacent means of a longitudinal connecting link to one connected curved section of an adjacent circumferential set of strut members;

each interior set of strut members also including at least one unconnected strut member consisting of a short diagonal section having a longitudinal length L2 fixedly joined to an unconnected curved section; and

the stent being further characterized by having the length L1 of each diagonal section being longer than the length L2 of each short diagonal section and for each interior circumferential set of strut members, the number of connected curved sections being equal to the number of unconnected curved sections.