U.S. patent application number 12/472106 was filed with the patent office on 2009-10-01 for stent geometry for improved flexibility.
This patent application is currently assigned to BOSTON SCIENTIFIC SCIMED, INC.. Invention is credited to Brent C. Gerberding.
Application Number | 20090248140 12/472106 |
Document ID | / |
Family ID | 21831682 |
Filed Date | 2009-10-01 |
United States Patent
Application |
20090248140 |
Kind Code |
A1 |
Gerberding; Brent C. |
October 1, 2009 |
STENT GEOMETRY FOR IMPROVED FLEXIBILITY
Abstract
A stent comprises one or more circumferential serpentine bands
and having alternating peak portions and trough portions. The peak
portions include shorter peak portions and longer peak portions.
The longer peak portions are of a longitudinal extent greater than
the shorter peak portions. The longer peak portions include first
bent peak portions which extend in a first direction non-parallel
to the longitudinal axis of the stent and second bent peak portions
which extend in a second direction non-parallel to the longitudinal
axis of the stent. Each first bent peak portion is
circumferentially adjacent to one second bent peak portion which
points toward the first bent peak portion and to one second bent
peak portion which points away from the first bent peak portion.
Adjacent first and second bent peak portions which point toward one
another are separated one from the other by at least one shorter
peak portion.
Inventors: |
Gerberding; Brent C.;
(Alameda, CA) |
Correspondence
Address: |
VIDAS, ARRETT & STEINKRAUS, P.A.
SUITE 400, 6640 SHADY OAK ROAD
EDEN PRAIRIE
MN
55344
US
|
Assignee: |
BOSTON SCIENTIFIC SCIMED,
INC.
Maple Grove
MN
|
Family ID: |
21831682 |
Appl. No.: |
12/472106 |
Filed: |
May 26, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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10026413 |
Dec 21, 2001 |
7537607 |
|
|
12472106 |
|
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Current U.S.
Class: |
623/1.18 ;
623/1.15 |
Current CPC
Class: |
A61F 2/915 20130101;
A61F 2/91 20130101; A61F 2002/91541 20130101; A61F 2002/91558
20130101; A61F 2002/91508 20130101 |
Class at
Publication: |
623/1.18 ;
623/1.15 |
International
Class: |
A61F 2/06 20060101
A61F002/06 |
Claims
1. A stent characterized by a longitudinal axis, the stent
comprising at least one serpentine band extending about the
circumference of the stent and having alternating peak portions and
trough portions, the peak portions including shorter peak portions
and longer peak portions, the longer peak portions of a
longitudinal extent greater than the shorter peak portions, the
longer peak portions including first bent peak portions which
extend in a first direction non-parallel to the longitudinal axis
of the stent and second bent peak portions which extend in a second
direction non-parallel to the longitudinal axis of the stent, each
first bent peak portion circumferentially adjacent to one second
bent peak portion which points toward the first bent peak portion
and to one second bent peak portion which points away from the
first bent peak portion, adjacent first and second bent peak
portions which point toward one another separated one from the
other by at least one shorter peak portion.
2. The stent of claim 1 wherein the trough portions include shorter
trough portions and longer trough portions, the longer trough
portions of a longitudinal extent greater than the shorter trough
portions, the longer trough portions including first bent trough
portions which extend in a first direction non-parallel to the
longitudinal axis of the stent and second bent trough portions
which extend in a second direction non-parallel to the longitudinal
axis of the stent, each first bent trough portion circumferentially
adjacent to one second bent trough portion which points toward the
first bent trough portion and to one second bent trough portion
which points away from the first bent trough portion, adjacent
first and second bent trough portions which point toward one
another separated one from the other by at least one shorter trough
portion.
3. The stent of claim 3 comprising a plurality of the serpentine
bands.
4. The stent of claim 3 wherein serpentine bands which are
longitudinally adjacent one another are connected one to the
other.
5. The stent of claim 3 wherein serpentine bands which are
longitudinally adjacent one another are connected one to the other
by at least one longitudinal connector extending from a shorter
peak portion of one serpentine band to a shorter trough portion on
a serpentine band which is longitudinally adjacent thereto.
6. The stent of claim 3 wherein serpentine bands which are
longitudinally adjacent one another are connected one to the other
by a plurality of longitudinal connectors which extend from shorter
peak portions of one serpentine band to shorter trough portions on
a serpentine band which is longitudinally adjacent thereto.
7. The stent of claim 6 wherein adjacent first and second bent
trough portions which point away from one another are not separated
by any shorter trough portions and adjacent first and second bent
peak portions which point away from one another are not separated
by any shorter peak portions.
8. The stent of claim 6 wherein adjacent first and second bent
trough portions which point away from one another are not separated
by any shorter trough portions, adjacent first and second bent peak
portions which point away from one another are not separated by any
shorter peak portions, adjacent first and second bent trough
portions which point toward one another are separated one from the
other by at least two shorter trough portions and adjacent first
and second bent peak portions which point toward one another are
separated one from the other by at least two shorter peak
portions.
9. The stent of claim 1 made of one or more shape memory
materials.
10. The stent of claim 1 constructed and arranged to be
self-expanding.
11. In combination, a stent as in claim 10 disposed on a catheter,
the stent restrained by a sheath.
12. A stent comprising at least one serpentine band with a
plurality of alternating peak portions and trough portions, the
peak portions including at least two bent peak portions which bend
toward one another, each of the bent peak portions wrapping at
least partially about an adjacent peak.
13. The stent of claim 12 wherein the trough portions including at
least two bent troughs portions which bend toward one another, each
of the bent trough portions wrapping at least partially about an
adjacent trough.
14. The stent of claim 13 comprising a plurality of the serpentine
bands.
15. The stent of claim 14 where adjacent serpentine bands are
connected one to the other via at least one connector extending
from a peak portion of one serpentine band to a trough portion of
an adjacent serpentine band.
16. The stent of claim 14 where adjacent serpentine bands are
connected one to the other via a plurality of connectors extending
from peak portions of one serpentine band to trough portions of an
adjacent serpentine band.
17. The stent of claim 16 wherein the connectors are parallel to
the longitudinal axis of the stent.
18. The stent of claim 16 wherein each connector has a first end
and a second end, the first and second end circumferentially
aligned one with the other.
19. The stent of claim 1 made of one or more shape memory
materials.
20. The stent of claim 1 constructed and arranged to be
self-expanding.
Description
BACKGROUND OF THE 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. Increased
flexibility in a stent, however, typically comes at the expense of
scaffolding strength. Moreover, design features which may result in
increased flexibility may also result in protruding edges which may
damage vessels walls or catheter balloons during delivery of the
stent through tortuous vasculature.
[0003] Extra flexibility is particularly desirable in
self-expanding stents which, during delivery, are typically
restrained via a restraining sheath on a catheter.
[0004] There remains a need for a stent which has a high degree of
flexibility in the unexpanded state and has adequate scaffolding
strength.
[0005] All US patents and applications and all other published
documents mentioned anywhere in this application are incorporated
herein by reference in their entirety.
[0006] Without limiting the scope of the invention a brief summary
of the claimed embodiments of the invention is set forth below.
Additional details of the summarized embodiments of the invention
and/or additional embodiments of the invention may be found in the
Detailed Description of the Invention below.
[0007] A brief abstract of the technical disclosure in the
specification is provided as well for the purposes of complying
with 37 C.F.R. 1.72.
BRIEF SUMMARY OF THE INVENTION
[0008] In one embodiment, the invention is directed to a stent
comprising at least one serpentine band extending about the
circumference of the stent and having alternating peak portions and
trough portions. The peak portions include shorter peak portions
and longer peak portions. The longer peak portions are of a
longitudinal extent greater than the shorter peak portions. The
longer peak portions include first bent peak portions which extend
in a first direction non-parallel to the longitudinal axis of the
stent and second bent peak portions which extend in a second
direction non-parallel to the longitudinal axis of the stent. Each
first bent peak portion is circumferentially adjacent to one second
bent peak portion which points toward the first bent peak portion
and to one second bent peak portion which points away from the
first bent peak portion. Adjacent first and second bent peak
portions which point toward one another are separated one from the
other by at least one shorter peak portion.
[0009] Desirably, the trough portions of the serpentine band
include shorter trough portions and longer trough portions. The
longer trough portions are of a longitudinal extent greater than
the shorter trough portions. The longer trough portions include
first bent trough portions which extend in a first direction
non-parallel to the longitudinal axis of the stent and second bent
trough portions which extend in a second direction non-parallel to
the longitudinal axis of the stent. Each first bent trough portion
is circumferentially adjacent to one second bent trough portion
which points toward the first bent trough portion and to one second
bent trough portion which points away from the first bent trough
portion. Adjacent first and second bent trough portions which point
toward one another are separated one from the other by at least one
shorter trough portion.
[0010] Typically, the inventive stents comprise a plurality of the
serpentine bands. Serpentine bands which are longitudinally
adjacent one another are connected one to the other by at least one
longitudinal connector and desirably a plurality of longitudinal
connectors extending from shorter peak portions of one serpentine
band to shorter trough portions on a serpentine band which is
longitudinally adjacent thereto.
[0011] In some embodiments of the invention, adjacent first and
second bent trough portions which point away from one another are
separated one from the other by one or more shorter trough portions
and adjacent first and second bent peak portions which point away
from one another are separated by one or more shorter peak
portions.
[0012] In other embodiments of the invention, adjacent first and
second bent trough portions which point away from one another are
not separated by any shorter trough portions and adjacent first and
second bent peak portions which point away from one another are not
separated by any shorter peak portions.
[0013] Typically, adjacent first and second bent trough portions
which point away from one another are not separated by any shorter
trough portions, adjacent first and second bent peak portions which
point away from one another are not separated by any shorter peak
portions, adjacent first and second bent trough portions which
point toward one another are separated one from the other by at
least two shorter trough portions and adjacent first and second
bent peak portions which point toward one another are separated one
from the other by at least two shorter peak portions.
[0014] The invention is also directed to a stent comprising at
least one serpentine band with a plurality of alternating peak
portions and trough portions. The peak portions include at least
two bent peak portions which bend toward one another. Each of the
bent peak portions wraps at least partially about an adjacent peak
portion. Desirably, the trough portions include at least two bent
trough portions which bend toward one another. Each of the bent
trough portions wraps at least partially about an adjacent trough
portion.
[0015] Typically, the inventive stents will comprise a plurality of
the serpentine bands. Where multiple serpentine bands are present,
adjacent serpentine bands may be connected one to the other via at
least one, and desirably, a plurality of connectors extending from
a peak portion of one serpentine band to a trough portion of an
adjacent serpentine band. The connectors may extend from any
portion of one serpentine band to any other portion of an adjacent
serpentine band. Desirably, adjacent serpentine bands are connected
one to the other via a plurality of connectors extending from peak
portions of one serpentine band to trough portions of an adjacent
serpentine band. More desirably, each connector has a first end and
a second end and the first and second end circumferentially aligned
one with the other. Even more desirably, the connectors are
parallel to the longitudinal axis of the stent.
[0016] Desirably, the inventive stents are made of one or more
shape memory materials.
[0017] Also desirably, the inventive stents are constructed and
arranged to be self-expanding.
[0018] The invention is also directed to the combination of an
inventive stent disclosed herein disposed on a catheter. Desirably,
the stent is self-expanding and is restrained by a sheath.
[0019] Additional details and/or embodiments of the invention are
discussed below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 is a flat layout view of an inventive stent.
[0021] FIG. 2 shows the flexing of a portion of the stent on
application of a force thereto.
[0022] FIG. 3 shows a side view of a catheter taken in
cross-section.
[0023] FIG. 4 shows a side view of a portion of a catheter with a
stent mounted thereon taken in cross-section as it may appear as it
is advanced through a vessel.
[0024] FIG. 5 shows an enlarged side view of a portion of the stent
shown in FIG. 4, on application of a substantially inward acting
force.
[0025] FIG. 6 shows an enlarged side view of a portion of the stent
shown in FIG. 4, on application of a substantially outward acting
force.
[0026] FIG. 7 is a flat layout view of a portion of a stent.
DETAILED DESCRIPTION OF THE INVENTION
[0027] 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.
[0028] For the purposes of this disclosure, like reference numerals
in the figures shall refer to like features unless otherwise
indicated.
[0029] In one embodiment, the invention is directed to a stent such
as that shown by way of example at 100 in FIG. 1, comprising at
least one serpentine band 104 extending about the circumference of
the stent and having alternating peak portions 108 and trough
portions 112. The peak portions include shorter peak portions 108a
and longer peak portions 108b,c. The longer peak portions are of a
longitudinal extent greater than the shorter peak portions. The
longer peak portions include first bent peak portions 108b which
extend in a first direction non-parallel to the longitudinal axis
101 of the stent and second bent peak portions 108c which extend in
a second direction non-parallel to the longitudinal axis of the
stent. Each first bent peak portion 108b is circumferentially
adjacent to one second bent peak portion 108c which points toward a
first bent peak portion and to one second bent peak portion which
points away from the first bent peak portion. Adjacent first and
second bent peak portions 108b and 108c which point toward one
another are separated one from the other by at least one shorter
peak portion 108a.
[0030] Desirably, the trough portions 112 of the serpentine band
include shorter trough portions 112a and longer trough portions
112b, 112 c. The longer trough portions are of a longitudinal
extent greater than the shorter trough portions. The longer trough
portions include first bent trough portions 112b which extend in a
first direction non-parallel to the longitudinal axis of the stent
and second bent trough portions 112c which extend in a second
direction non-parallel to the longitudinal axis of the stent. Each
first bent trough portion is circumferentially adjacent to one
second bent trough portion which points toward the first bent
trough portion and to one second bent trough portion which points
away from the first bent trough portion. Adjacent first and second
bent trough portions which point toward one another are separated
one from the other by at least one shorter trough portion.
[0031] The inventive stents disclosed herein may comprise a single
such serpentine band 104 or a plurality of such serpentine bands,
as shown in FIG. 1. In the latter case, where the stent includes
such serpentine bands which are longitudinally adjacent one
another, the adjacent serpentine bands are connected one to the
other. Desirably, adjacent serpentine bands are connected by one or
more connectors. The connectors may extend in a longitudinal
direction as shown in FIG. 1. Connectors 116 of FIG. 1 have
straight sides and extend longitudinally. The connectors may also
include one or more curved portions as long as the first and second
ends of the connectors are circumferentially aligned with one
another. Curved or straight connectors whose first and second ends
are longitudinally and circumferentially offset from one another
may be used in conjunction with the serpentine segments disclosed
herein in other embodiments of the invention. In the embodiment of
FIG. 1, the connectors are shorter in length than the longitudinal
extent of the serpentine bands. The invention contemplates closely
spaced serpentine bands, as shown in FIG. 1, serpentine bands which
abut one another as well as serpentine bands which are spaced
further apart than the spacing shown in FIG. 1. To that end, the
connectors may be as long as the serpentine bands or longer.
[0032] In an alternative embodiment of the invention shown in FIG.
7, each connector 116 is associated with at least two peak portions
108b and 108c.
[0033] As shown in FIG. 1, connectors 116 desirably extend from
shorter peak portions of one serpentine band to shorter trough
portions on a serpentine band which is longitudinally adjacent
thereto.
[0034] In some embodiments of the invention, such as for example,
the embodiment of FIG. 1, adjacent first and second bent trough
portions which point away from one another are separated one from
the other by one or more shorter trough portions and adjacent first
and second bent peak portions which point away from one another are
separated by one or more shorter peak portions.
[0035] In other embodiments of the invention, adjacent first and
second bent trough portions which point away from one another are
not separated by any shorter trough portions and adjacent first and
second bent peak portions which point away from one another are not
separated by any shorter peak portions.
[0036] Typically, as shown in FIG. 1, adjacent first and second
bent trough portions which point away from one another are not
separated by any shorter trough portions, adjacent first and second
bent peak portions which point away from one another are not
separated by any shorter peak portions, adjacent first and second
bent trough portions which point toward one another are separated
one from the other by at least two shorter trough portions and
adjacent first and second bent peak portions which point toward one
another are separated one from the other by at least two shorter
peak portions.
[0037] The invention is also directed to a stent, such as that
shown by way of example in FIG. 1 comprising at least one
serpentine band 104 with a plurality of alternating peak portions
108 and trough portions 112. The peak portions include at least two
bent peak portions 108b and 108c which bend toward one another.
Each of the bent peak portions wraps at least partially about an
adjacent peak portion 10a. Desirably, the trough portions 112
include at least two bent trough portions 112b and 112c which bend
toward one another. Each of the bent trough portions wraps at least
partially about an adjacent trough portion 112a.
[0038] Typically, the inventive stents will comprise a plurality of
the serpentine bands 104. Where multiple serpentine bands are
present, adjacent serpentine bands may be connected one to the
other via at least one, and desirably, a plurality of connectors
extending from a peak portion of one serpentine band to a trough
portion of an adjacent serpentine band. The connectors may extend
from any portion of one serpentine band to any other portion of an
adjacent serpentine band. Desirably, adjacent serpentine bands are
connected one to the other via a plurality of connectors extending
from peak portions of one serpentine band to trough portions of an
adjacent serpentine band. More desirably, each connector has a
first end and a second end and the first and second end
circumferentially aligned one with the other. Even more desirably,
as shown in FIG. 1, the connectors are parallel to the longitudinal
axis of the stent.
[0039] Because of the presence of circumferentially adjacent longer
first and second peak portions 108b and 108c which point toward one
another and which are separated one from the other by at least one
shorter peak portion 108a, a longitudinal force transmitted through
a connector 116 will be deflected off to the sides, as shown in
FIG. 2 thereby allowing cells to open and close. Also, because of
the presence of circumferentially adjacent longer first and second
trough portions 112b and 112c which point toward one another and
which are separated one from the other by at least one shorter
trough portion 112a, a longitudinal force transmitted through a
connector 116 will be deflected off to the sides thereby allowing
cells to open and close.
[0040] Any of the inventive stents disclosed above may be provided
with a uniform diameter or may taper in portions or along the
entire length of the stent. 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. For example, the width and/or
thickness of the circumferential serpentine bands and/or connectors
may increase or decrease along portions of the stent or along the
entire length of the stent. The longitudinal extent and number of
peaks and troughs of several successive serpentine bands may remain
constant while the width and/or thickness of the successive
serpentine bands decreases. Similarly, the longitudinal extent and
number of peaks and troughs of several successive serpentine bands
may remain constant while the width and/or thickness of the
successive serpentine bands decreases.
[0041] The inventive stents may also be modified, by choice of
material or geometry so that one or both ends are more rigid or
more flexible than the remainder of the stent.
[0042] The inventive stents may be manufactured using known stent
manufacturing techniques. Suitable methods for manufacturing the
inventive stents include laser cutting, chemical etching or
stamping of a tube. The inventive stents may also be manufactured
by laser cutting, chemically etching, stamping a flat sheet,
rolling the sheet and, optionally, welding the sheet. Other
suitable manufacturing techniques include electrode discharge
machining or molding the stent with the desired design. The stent
may also be manufactured by welding individual sections, for
example, circumferential bands, together. Any other suitable stent
manufacturing process may also be used.
[0043] Any suitable stent material may be used in the manufacture
of the inventive stents. Examples of such materials include
polymeric materials, metals, ceramics and composites. Suitable
polymeric materials include thermotropic liquid crystal polymers
(LCP's). Where the stent is made of metal, the metal may be
stainless steel, cobalt chrome alloys such as elgiloy, tantalum or
other plastically deformable metals. Other suitable metals include
shape-memory metals including nickel-titanium alloys generically
known as "nitinol", platinum/tungsten alloys and titanium
alloys.
[0044] The invention also contemplates the use of more than one
material in the inventive stents. For example, the serpentine bands
may be made of different materials. Optionally, the connectors may
be made of a different material than the serpentine bands.
[0045] 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. Desirably, the inventive stents are made in self-expanding
form.
[0046] The inventive stents may include suitable radiopaque
coatings. For example, the stents may be coated with gold or other
noble metals or sputtered with tantalum or other metals. 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. Other radiopaque metals which may be used
include platinum, platinum-tungsten, palladium, platinum-iridium,
rhodium, tantalum, or alloys or composites of these metals.
[0047] 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.
[0048] The inventive stents may also be provided with 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. Mechanical retention
devices may also be used to maintain the stent on the balloon
during delivery. To that end, the use of other coatings on the
inventive stents is also within the scope of the invention.
[0049] The coating may comprise one or more non-genetic therapeutic
agents, genetic materials and cells and combinations thereof as
well as other polymeric coatings.
[0050] Non-genetic therapeutic agents include anti-thrombogenic
agents such as heparin, heparin derivatives, urokinase, and PPack
(dextrophenylalanine proline arginine chloromethylketone);
anti-proliferative agents such as enoxaprin, angiopeptin, or
monoclonal antibodies capable of blocking smooth muscle cell
proliferation, hirudin, and acetylsalicylic acid; anti-inflammatory
agents such as dexamethasone, prednisolone, corticosterone,
budesonide, estrogen, sulfasalazine, and mesalamine;
antineoplastic/antiproliferative/anti-miotic agents such as
paclitaxel, 5-fluorouracil, cisplatin, vinblastine, vincristine,
epothilones, endostatin, angiostatin and thymidine kinase
inhibitors; anesthetic agents such as lidocaine, bupivacaine, and
ropivacaine; anti-coagulants such as D-Phe-Pro-Arg chloromethyl
keton, an RGD peptide-containing compound, heparin, antithrombin
compounds, platelet receptor antagonists, antithrombin antibodies,
anti-platelet receptor antibodies, aspirin, prostaglandin
inhibitors, platelet inhibitors and tick antiplatelet peptides;
vascular cell growth promotors such as growth factor inhibitors,
growth factor receptor antagonists, transcriptional activators, and
translational promoters; vascular cell growth inhibitors such as
growth factor inhibitors, growth factor receptor antagonists,
transcriptional repressors, translational repressors, replication
inhibitors, inhibitory antibodies, antibodies directed against
growth factors, bifunctional molecules consisting of a growth
factor and a cytotoxin, bifunctional molecules consisting of an
antibody and a cytotoxin; cholesterol-lowering agents; vasodilating
agents; and agents which interfere with endogenous vascoactive
mechanisms.
[0051] Genetic materials include anti-sense DNA and RNA, DNA coding
for, anti-sense RNA, tRNA or rRNA to replace defective or deficient
endogenous molecules, angiogenic factors including growth factors
such as acidic and basic fibroblast growth factors, vascular
endothelial growth factor, epidermal growth factor, transforming
growth factor .alpha. and .beta., platelet-derived endothelial
growth factor, platelet-derived growth factor, tumor necrosis
factor .alpha., hepatocyte growth factor and insulin like growth
factor, cell cycle inhibitors including CD inhibitors, thymidine
kinase ("TK") and other agents useful for interfering with cell
proliferation the family of bone morphogenic proteins ("BMP's"),
BMP-2, BMP-3, BMP-4, BMP-5, BMP-6 (Vgr-1), BMP-7 (OP-1), BMP-8,
BMP-9, BMP-10, BMP-11, BMP-12, BMP-13, BMP-14, BMP-15, and BMP-16.
Desirable BMP's are any of BMP-2, BMP-3, BMP-4, BMP-5, BMP-6 and
BMP-7. These dimeric proteins can be provided as homodimers,
heterodimers, or combinations thereof, alone or together with other
molecules. Alternatively or, in addition, molecules capable of
inducing an upstream or downstream effect of a BMP can be provided.
Such molecules include any of the "hedgehog" proteins, or the DNA's
encoding them.
[0052] Cells can be of human origin (autologous or allogeneic) or
from an animal source (xenogeneic), genetically engineered if
desired to deliver proteins of interest at the transplant site. The
cells may be provided in a delivery media. The delivery media may
be formulated as needed to maintain cell function and
viability.
[0053] Suitable polymer coating materials include polycarboxylic
acids, cellulosic polymers, including cellulose acetate and
cellulose nitrate, gelatin, polyvinylpyrrolidone, cross-linked
polyvinylpyrrolidone, polyanhydrides including maleic anhydride
polymers, polyamides, polyvinyl alcohols, copolymers of vinyl
monomers such as EVA, polyvinyl ethers, polyvinyl aromatics,
polyethylene oxides, glycosaminoglycans, polysaccharides,
polyesters including polyethylene terephthalate, polyacrylamides,
polyethers, polyether sulfone, polycarbonate, polyalkylenes
including polypropylene, polyethylene and high molecular weight
polyethylene, halogenated polyalkylenes including
polytetrafluoroethylene, polyurethanes, polyorthoesters, proteins,
polypeptides, silicones, siloxane polymers, polylactic acid,
polyglycolic acid, polycaprolactone, polyhydroxybutyrate valerate
and blends and copolymers thereof, coatings from polymer
dispersions such as polyurethane dispersions (for example,
BAYHDROL.RTM.), fibrin, collagen and derivatives thereof,
polysaccharides such as celluloses, starches, dextrans, alginates
and derivatives, hyaluronic acid, squalene emulsions. Polyacrylic
acid, available as HYDROPLUS.RTM. (Boston Scientific Corporation,
Natick, Mass.), and described in U.S. Pat. No. 5,091,205, the
disclosure of which is hereby incorporated herein by reference, is
particularly desirable. Even more desirable is a copolymer of
polylactic acid and polycaprolactone.
[0054] Other polymer materials that may be utilized with the
present invention include matrix compounds that induce inflammation
of the vessel. Some examples of such matrix compounds include but
are not limited to: lactide, glycolide, and caprolactone polymers
and their copolymers; hydroxybutyrate and polyhydroxyvalerate and
their block and random copolymers; a polyether ester; anhydrides,
polymers and copolymers of sebacic acid, hexadecandioic acid;
orthoesters; polydioxinone; polyglycolic acid and polylactic acid,
their block and random copolymers. Other compounds my be included
such as are described in U.S. Pat. No. 6,280,457, the contents of
which are incorporated in their entirety herein by reference.
[0055] The inventive stents may also be used as the framework for a
graft. Suitable coverings include nylon, collagen, PTFE and
expanded PTFE, polyethylene terephthalate and KEVLAR, 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
including synthetic polymers such as polyethylene, polypropylene,
polyurethane, polyglycolic acid, polyesters, polyamides, their
mixtures, blends and copolymers.
[0056] The inventive stents may find use in coronary arteries,
renal arteries, peripheral arteries including iliac arteries,
arteries of the neck and cerebral arteries. The stents of the
present invention, however, are not limited to use in the vascular
system and may also be advantageously employed in other body
structures, including but not limited to arteries, veins, biliary
ducts, urethras, fallopian tubes, bronchial tubes, the trachea, the
esophagus and the prostate.
[0057] The invention is also directed to the combination of an
inventive stent disclosed herein disposed on a catheter. Desirably,
the stent is self-expanding and is restrained by a sheath. 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. The inventive
stents may be delivered in conjunction with one or more stent
retaining sleeves. An example of stent retaining sleeves is
disclosed in U.S. provisional application 60/238,178. Desirably,
where an inventive self-expanding stent is used, the stent has a
restraining sheath disposed thereabout. An example of a catheter
and stent is shown at 200 in FIG. 3. Catheter 200 includes a
retractable sheath 210 which restrains self-expanding stent 100.
Additional details concerning the catheter may be found in U.S.
Pat. No. 5,957,930.
[0058] In practice the catheter may be inserted into a lumen,
vessel or other body space in order to advance the portion of the
catheter including the stent to a treatment site. It is known that
such spaces, particularly vessels, may be rather confined and
tortous in nature. As the distal end of the catheter is advanced
through a body space, the stent mounted upon the catheter may be
subjected to various inwardly acting and outwardly acting forces.
For example, in the embodiment shown in FIG. 4, as the catheter 200
is advanced around a curved portion 222 of a vessel 220, inward
facing portion 212 of the stent 100 will be subjected to a
substantially longitudinally inward acting force as the stent is
forced to bend around the curve 222. At the same time an outward
facing portions 214 of the stent 100 is subjected to a
substantially longitudinally outward acting force.
[0059] As is shown in the close-up view of FIG. 5, the
substantially longitudinally inward acting force, indicated by
arrows 216, causes, the peak portions 108b and 108c to flex in a
manner which results in angle O.sub.1 increasing.
[0060] As is shown in the close-up view of FIG. 6, however, the
substantially longitudinally outwardly acting force, indicated by
arrows 218, acting upon an individual outward facing portions 214
of the stent, will compress the peak portions 108b and 108c whereby
angle O.sub.2 is reduced.
[0061] The inventive stents may also be made from a single piece of
material. For example, a sheet of super-elastic material may be
provided and a stent pattern provided therein by laser cutting,
etching, mechanical cutting or any other suitable method.
Optionally, opposing edges of the sheet may be welded or otherwise
joined to one another.
[0062] The inventive stents may likewise be made from a tube. The
tube is provided with a stent design, as by laser cutting etching,
mechanical cutting and the like.
[0063] The inventive stents may find use in the cerebral arteries
as well as in the coronary arteries, the peripheral arteries and
the arteries of the neck. The stents of the present invention,
however, are not limited to use in the vascular system and may also
be advantageously employed in other body structures, including but
not limited to arteries, veins, biliary ducts, urethras, fallopian
tubes, bronchial tubes, the trachea, the esophagus and the
prostate. The inventive stents may be used interarterially in the
brain, deployed across the neck of an aneurysm as well as in
occlusions in bodily vessels. The size of the inventive stents will
be appropriate for the intended usage of the stent.
[0064] The above disclosure is intended to be illustrative and not
exhaustive. This 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 claims where the term "comprising" means "including,
but not limited to". 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. Further, the particular features presented in the dependent
claims can be combined with each other in other manners within the
scope of the invention such that the invention should be recognized
as also specifically directed to other embodiments having any other
possible combination of the features of the dependent claims. For
instance, for purposes of claim publication, any dependent claim
which follows should be taken as alternatively written in a
multiple dependent form from all prior claims which possess all
antecedents referenced in such dependent claim if such multiple
dependent format is an accepted format within the jurisdiction
(e.g. each claim depending directly from claim 1 should be
alternatively taken as depending from all previous claims). In
jurisdictions where multiple dependent claim formats are
restricted, the following dependent claims should each be also
taken as alternatively written in each singly dependent claim
format which creates a dependency from a prior
antecedent-possessing claim other than the specific claim listed in
such dependent claim below (e.g. claim 4 may be taken as
alternatively dependent from claim 2; claim 5 may be taken as
alternatively dependent on claim 2, or on claim 3; etc.).
[0065] This completes the description of the preferred and
alternate embodiments of the invention. Those skilled in the art
may recognize other equivalents to the specific embodiment
described herein which equivalents are intended to be encompassed
by the claims attached hereto.
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