U.S. patent application number 10/341865 was filed with the patent office on 2003-06-05 for stent designs.
Invention is credited to Doran, Burns P., Skubitz, Sean P..
Application Number | 20030105515 10/341865 |
Document ID | / |
Family ID | 24733396 |
Filed Date | 2003-06-05 |
United States Patent
Application |
20030105515 |
Kind Code |
A1 |
Skubitz, Sean P. ; et
al. |
June 5, 2003 |
Stent designs
Abstract
A stent may be constructed comprising a plurality of
interconnected circumferential bands each bands comprising a
plurality of concave and/or convex M-shaped segments joined
together by loops.
Inventors: |
Skubitz, Sean P.;
(Shoreview, MN) ; Doran, Burns P.; (Albertville,
MN) |
Correspondence
Address: |
VIDAS, ARRETT & STEINKRAUS, P.A.
6109 BLUE CIRCLE DRIVE
SUITE 2000
MINNETONKA
MN
55343-9185
US
|
Family ID: |
24733396 |
Appl. No.: |
10/341865 |
Filed: |
January 14, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10341865 |
Jan 14, 2003 |
|
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09681006 |
Nov 13, 2000 |
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6506211 |
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Current U.S.
Class: |
623/1.15 |
Current CPC
Class: |
A61F 2002/91533
20130101; A61F 2/88 20130101; A61F 2002/9155 20130101; A61F 2/915
20130101; A61F 2002/91508 20130101; A61F 2/91 20130101; A61F
2002/91516 20130101 |
Class at
Publication: |
623/1.15 |
International
Class: |
A61F 002/06 |
Claims
1. A stent having a proximal end and a distal end, the stent
comprising a plurality of interconnected circumferential bands with
a flowpath therethrough, at least one of the bands including at
least one substantially M-shaped segment selected from the group
consisting of convex M-shaped segments and concave M-shaped
segments.
2. The stent of claim 1 wherein the at least one M-shaped segment
is a convex M-shaped segment.
3. The stent of claim 2 wherein the convex M-shaped segment
comprises a first convex outer leg, a second convex outer leg and a
connector connecting the first convex outer leg and the second
convex outer leg.
4. The stent of claim 2 wherein the at least one band comprises a
plurality of convex M-shaped segments.
5. The stent of claim 2 comprising a first band having a plurality
of interconnected convex M-shaped segments and a second band having
a plurality of interconnected convex M-shaped segments.
6. The stent of claim 5 wherein adjacent convex M-shaped segments
in the first band are interconnected via a loop extending
therebetween.
7. The stent of claim 6 wherein the loop is formed of a concave
first portion and a concave second portion.
8. The stent of claim 5 wherein the convex M-shaped segments of the
first band are inverted relative to the convex M-shaped segments of
the second band.
9. The stent of claim 8 wherein the convex M-shaped segments of the
first bands at least partially abut and are connected.
10. The stent of claim 1 wherein the at least one M-shaped segment
is a concave M-shaped segment.
11. The stent of claim 10 wherein the concave M-shaped segment
comprises a first concave outer leg, a second concave outer leg and
a connector connecting the first concave outer leg and the second
concave outer leg.
12. The stent of claim 10 wherein the at least one band comprises a
plurality of concave M-shaped segments.
13. The stent of claim 12 wherein the first portion is
substantially parallel to the first concave leg of the first
concave M-shaped segment and the second portion is substantially
parallel to the second concave leg of the second concave M-shaped
segment.
14. The stent of claim 10 comprising a first band having a
plurality of interconnected concave M-shaped segments and a second
band having a plurality of interconnected concave M-shaped
segments.
15. The stent of claim 14 wherein adjacent concave M-shaped
segments in the first band are interconnected via a loop extending
therebetween.
16. The stent of claim 15 wherein the loop is formed of a convex
first portion and a convex second portion.
17. The stent of claim 14 wherein the concave M-shaped segments of
the first band are inverted relative to the concave M-shaped
segments of the second band.
18. The stent of claim 17 wherein the concave M-shaped segments of
the first bands at least partially abut and are connected.
19. The stent of claim 1 comprising a plurality of interconnected
convex M-shaped segments and concave M-shaped segments.
20. A stent comprising a plurality of connected tubular bands, at
least one of the tubular bands comprising a repeating pattern of
three or more substantially parallel interconnected segments with a
first curvature and three or more substantially parallel
interconnected segments with a second curvature, one of the
segments with the first curvature connected to one of the segments
with the second curvature.
21. The stent of claim 20 wherein the first curvature is opposite
the second curvature.
22. The stent of claim 20 wherein a plurality of the tubular bands
each comprise a repeating pattern of three or more-substantially
parallel interconnected segments with a first curvature and three
or more substantially parallel interconnected segments with a
second curvature, one of the segments of the first curvature
connected to one of the segments with the second curvature.
23. The stent of claim 22 wherein adjacent tubular bands are out of
phase with one another.
24. The stent of claim 22 wherein adjacent tubular bands are out of
phase with one another by ninety degrees.
Description
BACKGROUND OF INVENTION
[0001] The use of stents in bodily lumen is well known. A stent is
typically delivered in an unexpanded state to a desired location in
a bodily lumen and then expanded. The stent may be expanded via the
use of mechanical device such as a balloon or the stent may be
self-expanding.
[0002] Because a stent often must be delivered through tortuous
anatomy, it is desirable for the stent to be flexible. It is also
desirable for the stent to exhibit high scaffolding strength in the
expanded state. In general, however, as stent flexibility is
increased, scaffolding strength is decreased and similarly, as
scaffolding strength is increased, flexibility is decreased.
[0003] There remains a need for a stent having a high degree of
flexibility in the unexpanded state and high scaffolding strength
in the expanded state.
[0004] All US patents and applications and all other published
documents mentioned anywhere in this application are incorporated
herein by reference in their entirety.
[0005] The invention in various of its embodiment is summarized
below. Additional details of the invention and/or additional
embodiments of the invention may be found in the Detailed
Description of the Invention below.
SUMMARY OF INVENTION
[0006] In one embodiment, the invention is directed to a stent
comprising a plurality of interconnected circumferential bands with
a flowpath therethrough. At least one of the bands includes at
least one substantially M-shaped segment selected from the group
consisting of convex M-shaped segments and concave M-shaped
segments. In the case of a convex M-shaped segment, the segment
comprises a first convex outer leg, a second convex outer leg and a
connector connecting the first convex outer leg and the second
convex outer leg. In the case of a concave M-shaped segment, the
segment comprises a first concave outer leg, a second concave outer
leg and a connector connecting the first concave outer leg and the
second concave outer leg.
[0007] Desirably, the at least one band comprises a plurality of
M-shaped segments whether convex, concave or both. Where present,
adjacent convex M-shaped segments may be interconnected via a loop
extending therebetween. The loop may optionally comprise a concave
first portion and a concave second portion. Where present, adjacent
concave M-shaped segments may be interconnected via a loop
extending therebetween. The loop may optionally comprise a convex
first portion and a convex second portion. Where convex M-shaped
segments are present in multiple bands, they may optionally be
inverted relative to one another in adjacent bands. Similarly,
where concave M-shaped segments are present in multiple bands, they
may optionally be inverted relative to one another in adjacent
bands.
[0008] In another embodiment, the invention is directed to a stent
comprising a plurality of connected bands. At least one of the
bands comprises a repeating pattern of three or more substantially
parallel interconnected segments with a first curvature and three
or more substantially parallel interconnected segments with a
second curvature. One of the segments with the first curvature is
connected to one of the segments with the second curvature.
Desirably, the first curvature is opposite to the second curvature.
Also desirably, the stent comprises a plurality of the bands with
each band comprising a repeating pattern of three or more
substantially parallel interconnected segments with a first
curvature and three or more substantially parallel interconnected
segments with a second curvature, one of the segments of the first
curvature connected to one of the segments with the second
curvature.
[0009] In another embodiment, the invention is directed to a stent
comprising a plurality of interconnected circumferential bands
where at least one of the bands has a proximal end and a distal end
and one of the proximal and distal ends comprises at least one
first loop and at least one second loop. The first loop includes a
portion which is disposed substantially circumferentially and the
second loop includes a portion which is substantially arrow shaped.
Desirably, at least one of the bands comprises a plurality of first
and second loops alternating with one another. Also desirably, the
stent comprises a plurality of such bands. Adjacent bands may be
connected one to the other to form combined bands with openings
therein.
[0010] The invention is also directed to a stent comprising at
least one first cell having a first end and a second end. The first
end terminates in a circumferential component and the second end
terminates in an arrow-shaped component opposite the first end. The
stent may comprise a plurality of such interconnected first cells.
Desirably, the first cells are interconnected circumferentially
about the stent and/or longitudinally along the length of the
stent.
[0011] In another embodiment, the invention is directed to a stent
comprising a plurality of serpentine bands extending in a
longitudinal direction, including a first serpentine band and a
second serpentine band. The first and second serpentine bands are
connected by at least one loop member and desirably a plurality of
loop members extending in a direction non-parallel to the
longitudinal axis of the stent. All or some of the longitudinally
adjacent first loop members may open toward the proximal end of the
stent. Optionally, longitudinally adjacent first loop members may
be oppositely oriented about the longitudinal axis of the stent.
The stent may comprise additional serpentine bands extending in a
longitudinal direction and connected to adjacent serpentine bands
via additional first loop members.
[0012] In another embodiment, the invention is directed to a stent
comprising at least one first cell comprising a first generally
longitudinal sidewall having at least one bend therein, a second
generally longitudinal sidewall having at least one bend therein,
wherein the first generally longitudinal sidewall is substantially
parallel to the second generally longitudinal sidewall, a proximal
wall having at least one loop therein, the loop oriented
non-parallel to the longitudinal axis of the stent and a distal
wall having at least one loop therein, the loop oriented
non-parallel to the longitudinal axis of the stent. Desirably, the
stent comprises a plurality of such cells arranged longitudinally
and/or circumferentially about the stent. All of the loops in the
proximal walls of the cells and all of the loops in the distal
walls of the cells may be substantially parallel to one another or
may be non-parallel to one another.
[0013] In another embodiment, the invention is directed to a stent
comprising a plurality of bands, where each band comprises a
plurality of distally directed loops and a plurality of proximally
directed loops. Each distally directed loop has an open end and a
closed end and each proximally directed loop has an open end and a
closed end. The proximally directed loops and the distally directed
loops are nonparallel to the longitudinal axis of the stent and
alternate around the band. Optionally, the proximally directed
loops and the distally directed loops may be parallel to one
another. Circumferentially adjacent proximally directed loops and
distally directed loops are connected to one another by first
connectors which extend from the open end of the proximally
directed loops to the open end of the distally directed loops. The
first connectors include a circumferential component. Bands which
are adjacent one another are connected by one or more second
connectors extending therebetween. The second connectors desirably
have at least one bend therein.
[0014] In another embodiment, the invention is directed to a stent
defined by a structure comprising a plurality of serpentine
portions. Each serpentine portion has at least one peak and one
trough. At least some of the serpentine portions advance
discontinuously in a helical path about a longitudinal axis of the
stent to form a discontinuous helical band. The serpentine portions
may also be arranged such that at least some of the serpentine
portions advance discontinuously in a substantially longitudinal
path about a longitudinal axis of the stent to form a
discontinuousband extending substantially in a lengthwise
direction. Desirably, each of the serpentine portions forming the
discontinuous band consists of one peak and one trough where the
peak and trough are disposed at a non-zero angle with respect to
the longitudinal axis of the stent. Also desirably, the serpentine
portions may be arranged to form a plurality of discontinuous
helical bands or discontinuous bands extending substantially in a
lengthwise direction. All of the serpentine portions may be
connected so as to form a continuous path extending from one end of
the stent to the other end of the stent.
[0015] In yet another embodiment, the invention is directed to a
stent comprising a meandering path of connected serpentine
portions, each serpentine portion comprising first and second loop
portions which are arranged side-by-side and have a side in common.
The first and second loop portions each open in a non-longitudinal
direction. Adjacent serpentine portions along the meandering path
are connected by a connector having a longitudinal component and a
circumferential component. Furthermore, adjacent serpentine
portions along the meandering path are displaced longitudinally and
circumferentially from one another. The serpentine portions may be
arranged in at least one discontinuous band extending in a
substantially longitudinal direction or the discontinuous band may
extend substantially helically about a longitudinal axis of the
stent. Desirably, each serpentine portion consists of a first loop
and a second loop.
[0016] The invention is also directed to a stent comprising a
meandering, substantially helical path of connected serpentine
portions where each serpentine portion comprises first and second
loop portions which are arranged side-by-side and have a side in
common. The first and second loop portions each open in a
non-longitudinal direction. The serpentine portions may optionally
be arranged in at least one discontinuous band extending in a
substantially longitudinal direction or in at least one
discontinuous band extending substantially helically about a
longitudinal axis of the stent.
[0017] The invention is further directed to a stent comprising at
least one and desirably a plurality of omega building blocks. The
omega building block comprises a circumferentially oriented
omega-shaped loop, a substantially proximally oriented first lobe
extending from the proximal end of the omega-shaped loop and a
substantially distally oriented first lobe extending from the
distal end of the omega-shaped loop. Where a plurality of omega
building blocks are present, the omega building blocks are
desirably arranged in one or more bands extending in a lengthwise
direction. Longitudinally adjacent omega building blocks in the
band extending in a lengthwise direction are connected by dual lobe
members. Each dual lobe member comprises a substantially proximally
oriented second lobe and a substantially distally oriented second
lobe connected to the substantially proximally oriented second
lobe. The substantially proximally oriented second lobe is at the
proximal end of the dual lobe member and the substantially distally
oriented second lobe is at the distal end of the dual lobe member.
The substantially distally oriented first lobe of an omega building
block is arranged side by side and has a side in common with the
substantially proximally oriented second lobe of a dual lobe member
and the substantially proximally oriented first lobe of a
longitudinally adjacent omega building block is arranged side by
side and has a side in common with the substantially distally
oriented second lobe of the dual lobe member. At least one and
desirably a plurality and more desirably all of the omega shaped
loops are connected circumferentially to circumferentially adjacent
dual lobe members between the substantially proximally oriented
second lobe and the substantially distally oriented second
lobe.
BRIEF DESCRIPTION OF DRAWINGS
[0018] FIG. 1 illustrates a plan view of an expandable stent in
accordance with the present invention;
[0019] FIGS. 2a-f illustrates various connectors which may be used
in the inventive stent disclosed herein;
[0020] FIG. 3 illustrates a plan view of an expandable stent in
accordance with the present invention;
[0021] FIG. 4 illustrates a plan view of another inventive
stent;
[0022] FIG. 5 illustrates a plan view of another inventive
stent;
[0023] FIG. 6 illustrates a plan view of another inventive
stent;
[0024] FIG. 7 illustrates a plan view of another inventive
stent;
[0025] FIG. 8 illustrates a plan view of another inventive
stent;
[0026] FIG. 9 illustrates a plan view of another inventive stent;
and
[0027] FIG. 10 illustrates a plan view of another inventive
stent.
DETAILED DESCRIPTION
[0028] While this invention may be embodied in many different
forms, there are described in detail herein specific preferred
embodiments of the invention. This description is an
exemplification of the principles of the invention and is not
intended to limit the invention to the particular embodiments
illustrated.
[0029] In one embodiment, the invention is directed to a stent such
as that shown generally at 100 in FIG. 1. Stent 100, shown as a
flat pattern in FIG. 1, has a proximal end 102 and a distal end
104. Stent 100 comprises a plurality of interconnected
circumferential bands 106 and 108 with a flowpath therethrough.
Bands 106 are comprised of connected convex M-shaped segments 110
(shown highlighted) and bands 108 are comprised of connected convex
M-shaped segments 112 (shown highlighted). Convex M-shaped segments
112 are inverted relative to convex M-shaped segments 110. Bands
106 and 108 alternate over the length of the stent and adjacent
bands are connected to one another. As shown in FIG. 1, an upper
corner 114 of convex M-shaped segment 110 is connected to an upper
corner 116 of convex M-shaped segment 112 via connector 118.
Adjacent bands may also be connected by other suitable connectors
118 such as those shown in FIGS. 2a-f. The connectors may extend
exclusively in a longitudinal direction or may include a
circumferential component as shown in FIG. 1 and as described in
copending, commonly assigned U.S. application Ser. Nos. 08/511,076
and 09/197,278. Adjacent bands may be connected by a plurality of
connectors as shown in FIG. 1 or by a single connector.
[0030] Convex M-shaped segment 110 comprises a first convex outer
leg 120, a second convex outer leg 122 and a connector connecting
124 first convex outer leg 120 and second convex outer leg 122.
Inverted convex M-shaped segments 112 similarly comprise a first
convex outer leg, a second convex outer leg and a connector
connecting the first convex outer leg and the second convex outer
leg.
[0031] Adjacent convex M-shaped segments in a band are connected by
a loop 126 comprising a first portion 128 and a second portion 130.
First portion 128 is connected to a first concave leg 120 of a
first convex M-shaped segment and second portion 130 is connected
to a second concave leg 122 of an adjacent convex M-shaped
segment.
[0032] Desirably, as shown in FIG. 1, first portion 128 is
substantially parallel to first concave leg 120 of the convex
M-shaped segment and second portion 130 is substantially parallel
to second concave leg 122 of the adjacent convex M-shaped
segment.
[0033] The invention also contemplates other shaped loops.
Moreover, the invention contemplates connecting adjacent M-shaped
segments in a band with other types of connectors including any of
those shown in FIGS. 2a-f and those described in U.S. application
Ser. No. 09/197,278. Such connectors may extend in a purely
circumferential direction between points on adjacent M-shaped
segments in a band, whether at the proximal or distal ends of the
first and second legs of an M-shaped segment, the center or
anywhere else along the first and second legs. The connectors may
also include a longitudinal component.
[0034] The invention is also directed to a stent having at least
one concave M-shaped segment with concave legs as shown at 111 in
FIG. 1. Concave M-shaped segment 111 comprises first and second
concave legs connected by a loop portion.
[0035] The stent desirably comprises a plurality of concave
M-shaped segments 111 per band with circumferentially adjacent
concave M-shaped segments connected one to the other. Adjacent
bands are also interconnected.
[0036] As shown in FIG. 1, the stent may be constructed and
arranged to have overlapping convex and concave M-shaped segments
in each bands. In the embodiment shown in FIG. 1, the stent
comprises alternating first bands 106 having convex M-shaped
segments 110 and second bands 108 having convex M-shaped segments
112 which are inverted and similarly, concave M-shaped segments 111
and second bands 108 having concave M-shaped segments 113. The
inventive stents may also be formed of first bands and second bands
which do not alternate over the length of the stent. For example, a
first portion of the stent may comprise bands having M-shaped
segments of one orientation and a second portion of the stent may
comprise bands having inverted M-shaped segments.
[0037] The invention also contemplates stents formed exclusively of
bands of M-shaped segments where the M-shaped segments are
identically oriented.
[0038] The invention further contemplates stents having bands with
differing numbers of convex and/or concave M-shaped segments. For
example, a first band may consist of j M-shaped segments and a
second band may consist of k M-shaped segments where j is an
integer greater than k. Moreover, the stent may comprise different
bands having different amplitudes or differing strut widths and/or
thicknesses. The stent may be provided with a uniform diameter or
may taper.
[0039] The invention is also directed to a stent, such as that
shown generally at 100 in FIG. 1 where at one of the bands
comprises a repeating pattern of three or more substantially
parallel interconnected segments 115a-c with a first curvature and
three or more substantially parallel interconnected segments 117a-c
with a second curvature. One of the segments 115c with the first
curvature is connected to one of the segments 117a with the second
curvature. Desirably, the first curvature is opposite to the second
curvature. Also desirably, the stent comprises a plurality of the
bands with each band comprising a repeating pattern of three or
more substantially parallel interconnected segments with a first
curvature and three or more substantially parallel interconnected
segments with a second curvature, one of the segments of the first
curvature connected to one of the segments with the second
curvature.
[0040] In another embodiment, the invention is directed to a stent
such as that shown generally at 200 in FIG. 3. Stent 200, shown as
a flat pattern in FIG. 3, has a proximal end 202 and a distal end
204. The stent comprises a plurality of interconnected bands 206
and 208. Bands 206 and 208 are defined by-a plurality of
alternating first loops 210 (shown shaded) and second loops 212
(shown shaded). First loops 210 include a circumferential portion
214 which is disposed substantially circumferentially and second
loops 212 include a substantially arrow-shaped portion 216.
Substantially arrow shaped is defined here to be any shape
resembling the head of an arrow. Bands 206 and 208 resemble one
another but are oppositely oriented. That is, the arrow shaped
loops of bands 206 point in the proximal direction and the arrow
shaped loops of bands 208 point in the distal direction. Bands 206
and 208 are also 180 degrees out of phase with one another.
[0041] Adjacent bands 206 and 208 are joined end-to-end to form a
combined band 220. Combined bands 220 have a plurality of openings
222 therein. As shown in FIG. 3, adjacent bands 206 and 208 abut
one another. Adjacent bands 206 and 208 may also be connected using
any of the connectors shown in FIGS. 2a-f. The connectors may
extend entirely in a longitudinal direction or may also include a
circumferential component.
[0042] Adjacent combined bands are connected end-to-end along the
length of the stent via connectors 218. Connectors 218 may also be
replaced by any of the connectors shown in FIGS. 2a-f. The
connectors may extend entirely in a longitudinal direction or may
also include a circumferential component.
[0043] The invention is further directed to stents having a single
combined band 220, the proximal or distal end of which comprises at
least one first loop 210 and at least one second loop 212.
Desirably, the first loop 210 is an arrow shaped loop at one end
and second loop 212 comprises a substantially circumferential
portion 214 at one end. More desirably, the stent comprises at
least one combined band 220 having a plurality of first loops 210
and second loops 212 and even more desirably, the first and second
loops alternate with one another.
[0044] The invention is also directed to a stent such as that shown
generally at 200 in FIG. 3, comprising at least one first cell 224
(shown highlighted) having a first end 226 and a second end 228.
First end 226 terminates in a circumferential component and second
end 228 terminates in an arrow-shaped component opposite first end
226. Desirably, the stent comprises a plurality of interconnected
first cells. The first cells may be interconnected
circumferentially about the stent in bands and/or longitudinally
along the length of the stent. The first cells may be connected
longitudinally and/or circumferentially as shown in FIG. 3 or using
any of the connecting elements shown in FIGS. 2a-f. The connectors
may be exclusively longitudinal or circumferential or may include
longitudinal and circumferential components.
[0045] As shown in FIG. 3, the orientation of circumferentially
adjacent first cells 224 alternate. The first end of every other
first cell 224 points in the proximal direction. The invention also
contemplates embodiments in which every first cell is identically
oriented.
[0046] Where the stent comprises a plurality of bands 220 of first
cells 224, each band may consist of identically oriented first
cells or first cells with alternating orientations. The invention
also contemplates providing one or more bands having first cells
oriented exclusively in one direction and one or more bands having
first cells oriented exclusively in the opposite direction. Such
bands may alternate over the length of the stent or may be provided
in any other order along the length of the stent.
[0047] The invention further contemplates stents having bands 220
with differing numbers of first cells 224. For example, a first
band may consist of j first cells and a second band may consist of
k first cells where j is an integer greater than k. Moreover, the
stent may comprise different bands having different amplitudes or
longitudinal lengths or differing strut widths and/or thicknesses.
The stent may be provided with a uniform diameter or may taper.
[0048] In another embodiment, as shown in FIG. 4, the invention is
directed to a stent, shown generally at 300, having a proximal end
302 and a distal end 304. Stent 300 comprises a plurality of
serpentine bands 306 extending in a longitudinal direction,
including a first serpentine band 306a and a second serpentine band
306b. First serpentine band 306a and second serpentine band 306b
are connected by at least one and desirably a plurality of loop
members 308a extending in a direction non-parallel to the
longitudinal axis of the stent. Longitudinally adjacent first loop
members 308a connecting first serpentine band 306a and second
serpentine band 306b open toward the proximal end of the stent.
Longitudinally adjacent first loop members 308a may be non-parallel
to one another, oppositely oriented about the longitudinal axis of
the stent as shown in FIG. 4 or may be substantially parallel to
one another, as shown in FIG. 5.
[0049] Stent 300 further comprises a third serpentine band 306c
extending in the longitudinal direction. Third band 306c is
adjacent to second band 306b and connected thereto via a plurality
of second loop members 308b. Second loop members 308b open toward
the distal end of the stent. Longitudinally adjacent second loop
members 308b may be non-parallel to one another, oppositely
oriented about the longitudinal axis of the stent as shown in FIG.
4 or may be substantially parallel to one another, as shown in FIG.
5.
[0050] As shown in FIGS. 4 and 5, additional serpentine bands may
be present as well, interconnected with loop members as described
above.
[0051] The invention is also directed to a stent, such as that
shown generally at 300 in FIG. 4, comprising at least one first
cell 320 (shown highlighted) comprising a first generally
longitudinal sidewall 322 desirably having at least one bend
therein and a second generally longitudinal sidewall 324 having at
least one bend therein. First generally longitudinal sidewall 322
is substantially parallel to second generally longitudinal sidewall
324. Cell 320 further comprises a proximal wall 326 having at least
one loop 328 therein and a distal wall 330 having at least one loop
332 therein. Loops 328 and 332 are oriented non-parallel to the
longitudinal axis of the stent.
[0052] Desirably, the stent comprises a plurality of first cells
arranged longitudinally in one or more rows along the length of the
stent. The first cells are also seen to be arranged
circumferentially in bands about the stent. In the embodiment shown
in FIG. 4, for each cell, the loop in the proximal wall is
non-parallel to the loop in the distal wall. In another embodiment
of the invention, as shown in FIG. 5, all of the loops in the
proximal walls of the cells and all of the loops in the distal
walls of the cells are substantially parallel to one another.
[0053] The invention is also directed to stents such as those shown
in FIGS. 4 and 5 which are comprised of a plurality of bands 350
(shown highlighted) where each band comprises a plurality of
distally directed loops 308b and a plurality of proximally directed
loops 308a. Each distally directed loop 308b has an open end 352
and a closed end 354 and each proximally directed loop 308a has an
open end 356 and a closed end 358. Desirably, proximally directed
loops 308a and distally directed loops 308b are parallel to one
another and non-parallel to the longitudinal axis of the stent. The
proximally directed loops and the distally directed loops alternate
around the band and are connected to one another by first
connectors 360 which extend from the open end 356 of the proximally
directed loops 308a to the open end 352 of the distally directed
loops 308b. First connectors 360 include a circumferential
component. Bands which are adjacent one another are connected by
one or more second connectors 362 extending therebetween. Second
connector 362 desirably has at least one bend therein and more
desirably, two bends.
[0054] As shown in FIGS. 4 and 5, the proximally directed loops in
adjacent bands may be non-parallel with one another or parallel
with one another.
[0055] The stents of FIGS. 4 and 5 may be provided in a number of
variants. For example, the stent may be provided with a uniform
diameter or may taper. Also, the width and/or thickness of the
serpentine bands and/or connectors may increase or decrease along a
portion of the stent.
[0056] In another embodiment, the invention is directed to a stent
such as that shown generally at 400 in FIG. 6. Stent 400 has a
proximal end 402 and a distal end 404 and is defined by a structure
comprising a plurality of serpentine portions 406 (shown
highlighted). Each serpentine portion 406 has at least one peak 408
and one trough 410, desirably disposed at a non-zero angle with
respect to the longitudinal axis 414 of the stent. Also desirably,
each serpentine portion consists of one peak and one trough
although additional peaks and/or troughs may be present.
[0057] Serpentine portions 406 may be provided in a variety of
shapes. Desirably, however, the serpentine portions will be in the
shape shown in FIG. 6, namely, in the shape of a first omega 418
joined side by side with a second omega 420, the second omega
inverted relative to the first omega and the first and second
omegas having a side 422 in common. The omegas are disposed at a
non-zero angle relative to the longitudinal axis of the stent.
[0058] At least some of the serpentine portions 406 advance
discontinuously along a helical path 412a about a longitudinal axis
414 of the stent to form a discontinuous helical band 416a.
Desirably, serpentine portions 406 are arranged to form a plurality
of discontinuous helical bands (e.g. 416b, 416c). The stent of FIG.
6 is provided with three such discontinuous helical bands. Fewer or
additional discontinuous helical bands may be provided.
[0059] As shown in FIG. 6, all adjacent serpentine portions 406
within a discontinuous helical band (416a,b, or c) are separated
from one another by gaps. Where the stent comprises a multiplicity
discontinuous helical bands, adjacent discontinuous helical bands
(for example 416a-c) may optionally be connected to one another at
one or more locations 424.
[0060] Desirably, as shown in FIG. 6, serpentine portions 406 are
connected so as to form a continuous path extending from one end of
the stent to the other end of the stent.
[0061] The embodiment of FIG. 6 may also be modified so that
discontinuous bands extending in a lengthwise direction are formed
as is shown generally in FIG. 7. Stent 500 has a proximal end 502
and a distal end 504 and is defined by a structure comprising a
plurality of serpentine portions 506 (shown highlighted). Each
serpentine portion 506 has at least one peak 508 and one trough
510, desirably disposed at a non-zero angle with respect to the
longitudinal axis 514 of the stent. Also desirably, each serpentine
portion consists of one peak and one trough although additional
peaks and/or troughs may be present.
[0062] Serpentine portions 506 may be provided in a variety of
shapes. Desirably, however, the serpentine portions will be in the
shape shown in FIG. 7, namely, in the shape of a first omega 518
joined side by side with a second omega 520, the second omega
inverted relative to the first omega and the first and second
omegas having a side 522 in common. The omegas are disposed at a
non-zero angle relative to the longitudinal axis of the stent.
[0063] At least some of the serpentine portions 506 advance
discontinuously along a longitudinal path 512 about a longitudinal
axis 514 of the stent to form a discontinuous bands 516a extending
in a lengthwise direction. Desirably, serpentine portions 506 are
arranged to form a plurality of discontinuous bands extending in a
lengthwise direction (e.g. 516b, 516c). The stent of FIG. 7 is
provided with a total of four such discontinuous bands extending in
a lengthwise direction. Fewer or additional discontinuous bands
extending in a lengthwise direction may be provided.
[0064] As shown in FIG. 7, all adjacent serpentine portions 506
within a discontinuous band (516a,b, or c) extending in a
lengthwise direction are separated from one another by gaps. Where
the stent comprises a multiplicity discontinuous bands extending in
a lengthwise direction, adjacent discontinuous bands extending in a
lengthwise direction (for example 516a-c) may optionally be
connected to one another at one or more locations 524.
[0065] Desirably, as shown in FIG. 7, serpentine portions 506 are
connected so as to form a continuous path extending from one end of
the stent to the other end of the stent.
[0066] The stents of FIGS. 6 and 7 and their variants discussed
above may be provided with connectors to bridge the gap between
adjacent serpentine portions within a given discontinuous helical
(or longitudinal) band. As shown in FIG. 7, connector 532 connects
serpentine portion 510a to adjacent serpentine portion 510b in
discontinuous band 516a extending in a lengthwise direction. Some
or all of the gaps within a discontinuous longitudinal (or helical
band) may thus be bridged. Connectors 532 may be straight or curved
and may be of the same thickness and/or width as the serpentine
portions of the stent or may be of a smaller width and/or
thinner.
[0067] One or more additional connectors may also be provided to
directly connect circumferentially adjacent serpentine portions. An
example of such a connector is shown in FIG. 7. Connector 534
extends between circumferentially adjacent serpentine portion 510a
and 510c. Connectors 534 may be straight or curved and may be of
the same thickness and/or width as the serpentine portions of the
stent or may be of a smaller width and/or thinner.
[0068] In addition to the stent formation techniques disclosed
below, the stents of FIGS. 6 and 7 and their variants may be made
by winding a wire in the desired pattern. The ends of the wire may
optionally be secured to the stent as shown in FIGS. 6 and 7.
[0069] As shown in FIGS. 6 and 7, the invention is also directed to
a stent comprising a meandering path of connected serpentine
portions 406 (506). Each serpentine portion comprises a first loop
portion 408 (508) and a second loop portion 410 (510) which are
arranged side-by-side and have a side in common. The first and
second loop portions each open in a non-longitudinal direction.
Adjacent serpentine portions along the meandering path are
connected to one another end-to-end and are displaced
longitudinally and circumferentially from one another along the
meander path.
[0070] The serpentine portions may be arranged substantially
helically about a longitudinal axis of the stent as shown in FIG.
6, or in at least one discontinuous band extending in a
substantially longitudinal direction as shown in FIG. 7.
[0071] The invention is also directed, as shown in FIGS. 6 and 7,
to a stent comprising a meandering, substantially helical path of
connected serpentine portions. Each serpentine portion comprises
first and second loop portions which are arranged side-by-side and
have a side in common. The first and second loop portions each open
in a non-longitudinal direction. The serpentine portions may be
arranged in at least one discontinuous band extending substantially
helically about a longitudinal axis of the stent or may be arranged
in at least one discontinuous band extending in a substantially
longitudinal direction.
[0072] In addition to the variation discussed above, the stents of
FIGS. 6 and 7 and their variants may have a uniform diameter or may
taper. Also, the-width and/or thickness of the serpentine portions
may increase or decrease along a portion of the stent.
[0073] The invention is also directed to a stent such as that shown
generally at 600 in FIG. 8. Stent 600 has a proximal end 602, a
distal end 604 and a longitudinal axis 612. Stent 600 comprises an
omega building block 606 (shown highlighted). Omega building block
606 comprises a circumferentially oriented omega-shaped loop 608
having a proximal end and a distal end, a substantially proximally
oriented first lobe 614 extending from the proximal end of
omega-shaped loop 608 and a substantially distally oriented first
lobe 615 extending from the distal end of omega-shaped loop 608.
Desirably, stent 600 comprises a plurality of interconnected omega
building blocks 606 arranged in a band 616 extending in a
lengthwise direction along the stent. Desirably, longitudinally
adjacent omega building block members 606 in the band 616 extending
in a lengthwise direction are connected by dual lobe members 620
(shown highlighted). Dual lobe member 620 comprises a substantially
proximally oriented second lobe 622 and a substantially distally
oriented second lobe 624 connected to the substantially proximally
oriented second lobe 622. The substantially distally oriented first
lobe 615 of an omega building block 606 is arranged side by side
and has a side in common with the substantially proximally oriented
second lobe 622 of a dual lobe member 620. The substantially
proximally oriented first lobe 614 of a longitudinally adjacent
omega building block 606 is arranged side by side and has a side in
common with the substantially distally oriented second lobe 624 of
the dual lobe member 620.
[0074] Desirably, as shown in FIG. 8, the stent comprises a
plurality of longitudinally adjacent dual lobe members. More
desirably, the stent comprises a plurality of bands extending in a
lengthwise direction of omega building blocks.
[0075] At least one of the omega shaped loops 606 is connected
circumferentially to a circumferentially adjacent dual lobe member
620 between the substantially proximally oriented second lobe and
the substantially distally oriented second lobe as shown in FIG. 8.
Any of the other connectors shown in FIGS. 2a-2f may also be used.
More desirably, each of the omega shaped loops is connected
circumferentially to a circumferentially adjacent dual lobe member
between the substantially proximally oriented second lobe and the
substantially distally oriented second lobe.
[0076] The stent may be comprise a plurality of interconnected
closed longitudinal strips 630. Each closed longitudinal strip
comprises two bands extending in a lengthwise direction of omega
building blocks and two bands extending in a lengthwise direction
of dual lobe members. The stent shown in FIG. 8 comprises four such
longitudinal strips. The inventive stent may comprise fewer
longitudinal strips or additional longitudinal strips. Moreover,
the longitudinal strips may be modified to have additional bands
extending in a lengthwise direction of omega building blocks and
bands extending in a lengthwise direction of dual lobe members.
[0077] In addition to the various techniques described below, the
inventive stent of FIG. 8 and related embodiments may be made by
winding a wire in the desired pattern.
[0078] Another embodiment of the inventive stents is shown
generally at 700 in FIG. 9. Stent 700, having a proximal end 702
and a distal end 704, comprises a plurality of circumferential
bands 705 (one of which is shown highlighted) and a plurality of
bands extending in a lengthwise direction 706 (one of which is
shown highlighted) which significantly overlap the circumferential
bands. The embodiment of FIG. 9 includes four bands extending in a
lengthwise direction. More generally, the invention contemplates
providing at least one and desirably a plurality of bands extending
in a lengthwise direction. Adjacent circumferential bands include
two types of connecting regions, a first region where a portion 709
(one of which is shown highlighted) of a band extending in a
lengthwise direction extends between adjacent circumferential bands
and a second region where adjacent circumferential bands have a
segment 711 (one of which is shown highlighted) in common. The
circumferential bands are made of a plurality of hairpin curves 713
which alternate in orientation from a distal orientation 713a to a
proximal orientation 713b. Circumferentially adjacent hairpin
curves are separated and joined together by a curved portion 715 of
the band extending in a lengthwise direction. It is noted that the
struts forming the bands extending in a lengthwise direction are of
a different width than the struts forming the hairpin curves. As
such, the circumferential bands are formed in a repeating pattern
of two wider struts followed by a narrower strut. The invention
also is directed to embodiments in which all of the struts are of
the same width.
[0079] It is also noted that the stent of FIG. 9 comprises a
plurality of circumferential segments each comprising one or more
R-shaped segments 717a (one of which is shown highlighted).
Desirably, as shown in FIG. 9, the R-shaped segments are disposed
at an oblique angle relative to the longitudinal axis of the stent.
Also desirably, each band includes both R-shaped segments 717a and
inverted R-shaped segments 717b. In the embodiment of FIG. 9,
adjacent bands are interconnected by connectors. Also, adjacent
R-shaped segments and inverted R-shaped segments in adjacent bands
share a portion in common. In accordance with the invention, the
inventive stents may have as few as a single R-shaped segment.
Desirably, however, one or more R-shaped segments are provided in
each band and more desirably, a plurality of such segments are
provided.
[0080] The invention is also directed to a stent, as shown in FIG.
9, comprising a plurality of circumferential bands 705 which are
interconnected by one or more connectors 709 extending between
adjacent bands and which further are further connected by one or
more segments 711 shared in common between adjacent bands.
[0081] Yet another embodiment of the invention is shown at 800 in
FIG. 10. Stent 800, having a proximal end 802 and a distal end 804,
comprises a plurality of bands 806 extending in a lengthwise
direction (one of which is shown highlighted) of a first strut
width interconnected by a plurality of circumferential connectors
805 (one of which is shown highlighted). Bands 806 extending in a
lengthwise direction include substantially oppositely directed
loops 808a,b. Circumferential connectors 805 desirably have a strut
width which is narrower than the strut width of bands 806 extending
in a lengthwise direction although the invention also contemplates
the struts being of the same width or wider. Circumferential
connectors 805 include loop 807a oriented in the distal direction,
loop 807b oriented in the proximal direction, and two loops 809a
and 809b oriented in opposite substantially circumferential
directions. Proximally and distally oriented loops 807a,b are
disposed between adjacent bands 806 extending in a lengthwise
direction. Substantially circumferentially oriented loops 809a,b
are each nested in loops of adjacent bands 806 extending in a
lengthwise direction.
[0082] More generally, the invention is directed to a stent having
one or more bands extending in a lengthwise direction and one or
more circumferential members. The circumferential members have two
or more loops at least one of which points substantially in the
proximal direction and at least one of which points substantially
in the distal direction. The circumferential members also include
at least two loops which point in opposite, substantially
circumferential directions. Desirably, a plurality of longitudinal
members are present. More desirably, the longitudinal members also
include loops which are oriented in substantially circumferential
directions. Even more desirably, at least some of the substantially
circumferential loops of the circumferential members are nested
within substantially circumferential loops of the longitudinal
members. A stent in accordance with this embodiment is shown in
FIG. 10.
[0083] The invention is also directed to a stent comprising at
least one and desirably a plurality of longitudinal elements form a
repeat pattern of increasing width followed by a branching of the
longitudinal element with the branch connecting the longitudinal
element to an adjacent longitudinal element. The longitudinal
element decreases in width at the branch and then increases in
width again until another branch point is encountered. A stent in
accordance with this embodiment is shown in FIG. 10.
[0084] Any of the inventive stents disclosed above may be provided
with a uniform diameter or may taper. Also, the width and/or
thickness of the various portions of the inventive stents may
increase or decrease along a given portion of the stent.
[0085] Any of the inventive stents described above as comprising
bands may include one or more bands of a first amplitude and one or
more bands of a second amplitude different from the first
amplitude. Also, those stents described above which are comprised
of bands with repeating structural units may include one or more
bands with a first number of structural units and one or more bands
with a second number of structural units different from the first
number. Examples of structural units include M-shaped segments 110
of FIG. 1 and cells 224 of FIG. 3. Bands with different amplitudes
and/or numbers of repeating structural units may alternate with one
another along the length of the stent. Bands with like amplitudes
and/or numbers of repeating structural units may also be grouped
together.
[0086] The inventive stents may be manufactured using known stent
manufacturing techniques. Suitable methods for manufacturing the
inventive stents include laser cutting, chemical etching,
electroforming or stamping of a tube. The inventive stents may also
be manufactured by laser cutting, chemically etching, stamping or
electroforming a flat sheet, rolling the sheet and welding the
sheet, by electrode discharge machining, or by molding the stent
with the desired design. The inventive stents may also be made by
growing or extruding or winding a stent with the inventive
patterns.
[0087] Any suitable stent material may be used in the manufacture
of the inventive stents. Examples of such materials include metals
such as stainless steel, tantalum, elgiloy and shape memory metals
such as nitinol and shape memory polymers. The inventive stents may
also be made of suitable polymeric materials.
[0088] The inventive stents may include suitable radiopaque
coatings. For example, the stents may be coated with gold or
sputtered with tantalum. The stents may also be made directly from
a radiopaque material to obviate the need for a radiopaque coating
or may be made of a material having a radiopaque inner core.
[0089] The inventive stents may also be provided with various
bio-compatible coatings to enhance various properties of the stent.
For example, the inventive stents may be provided with lubricious
coatings. The inventive stents may also be provided with
drug-containing coatings which release drugs over time. Suitable
coatings include a sugar or more generally a carbohydrate and/or a
gelatin to maintain the stent on a balloon during delivery of the
stent to a desired bodily location. Other suitable compounds for
treating the stent include biodegradable polymers and polymers
which are dissolvable in bodily fluids. Portions of the interior
and/or exterior of the stent may be coated or impregnated with the
compound. Subjecting the stent to such a treatment also may prevent
flaring of the ends of the stent during delivery of the stent.
Mechanical retention devices may also be used to maintain the stent
on the balloon during delivery.
[0090] The inventive stents may be provided in mechanically
expandable form, in self-expanding form or as a hybrid of the two.
Mechanically expandable stents, in accordance with the invention,
may be expanded using any suitable mechanical device including a
balloon.
[0091] The inventive stents may be used for coronary arteries,
peripheral arteries, arteries of the neck and intracranial
arteries. More generally, the inventive stents may be used for any
vessel of the human body including but not limited to arteries,
veins, biliary ducts, urethras, fallopian tubes, bronchial tubes,
the trachea and the esophagus.
[0092] Suitable stent delivery devices such as those disclosed in
U.S. Pat. No. 6,123,712, U.S. Pat. No. 6,120,522 and U.S. Pat. No.
5,957,930 may be used to deliver the inventive stents to the
desired bodily location. The choice of delivery device will depend
on whether a self-expanding or balloon expandable stent is
used.
[0093] The inventive stents may also be used as the framework for a
graft. Suitable coverings include PTFE and expanded PTFE or any of
the materials disclosed in U.S. Pat. No. 5,824,046 and U.S. Pat.
No. 5,755,770. More generally, any known graft material may be
used.
[0094] In addition to the specific embodiments claimed below, the
invention is also directed to other embodiments having any other
possible combination of the dependent features claimed below taken
in conjunction with the independent claims from which they
depend.
[0095] The above disclosure is intended to be illustrative and not
exhaustive. The description will suggest many variations and
alternatives to one of ordinary skill in this art. All these
alternatives and variations are intended to be included within the
scope of the attached claims. Those familiar with the art may
recognize other equivalents to the specific embodiments described
herein which equivalents are also intended to be encompassed by the
claims attached hereto.
* * * * *