U.S. patent application number 10/374211 was filed with the patent office on 2004-08-26 for locking stent.
Invention is credited to Fleming, James A. III.
Application Number | 20040167610 10/374211 |
Document ID | / |
Family ID | 32771436 |
Filed Date | 2004-08-26 |
United States Patent
Application |
20040167610 |
Kind Code |
A1 |
Fleming, James A. III |
August 26, 2004 |
Locking stent
Abstract
A locking stent has a lattice of interconnecting elements
defining a substantially cylindrical configuration having a first
open end and a second open end. The lattice has a closed
configuration and an open configuration. The lattice also has a
plurality of adjacent hoops wherein each hoop is separated from
another hoop in the closed configuration. Each hoop mateably
connects with or interlocks with an adjacent hoop in the open
configuration.
Inventors: |
Fleming, James A. III;
(Bethlehem, PA) |
Correspondence
Address: |
PHILIP S. JOHNSON
JOHNSON & JOHNSON
ONE JOHNSON & JOHNSON PLAZA
NEW BRUNSWICK
NJ
08933-7003
US
|
Family ID: |
32771436 |
Appl. No.: |
10/374211 |
Filed: |
February 26, 2003 |
Current U.S.
Class: |
623/1.15 |
Current CPC
Class: |
A61F 2/915 20130101;
A61F 2/91 20130101; A61F 2230/0054 20130101; A61F 2002/91533
20130101; A61F 2002/91583 20130101; A61F 2002/91591 20130101 |
Class at
Publication: |
623/001.15 |
International
Class: |
A61F 002/06 |
Claims
What is claimed is:
1. A stent comprising: a lattice of interconnecting elements
defining a substantially cylindrical configuration having a first
open end and a second open end, the lattice having a closed
configuration and an open configuration; the lattice comprising a
plurality of adjacent hoops, each hoop separated from another hoop
in the closed configuration and each hoop interlocking with another
hoop in the open configuration.
2. The stent according to claim 1, wherein each hoop comprises a
plurality of loops.
3. The stent according to claim 2, wherein each hoop further
comprises a plurality of struts connected to the loops.
4. The stent according to claim 3, wherein at least one loop of one
hoop comprises a male end and at least one loop of another hoop
comprises a female end, wherein the male end is separated from the
female end when the lattice is in the closed configuration and
wherein the male end is mateably connected to the female end when
the lattice is in the open configuration.
5. The stent according to claim 4, wherein the male end of at least
one loop of one hoop and the female end of at least one loop of
another hoop form a locked joint when the lattice is in the open
configuration.
6. The stent according to claim 5, wherein the lattice further
comprises at least one flexible link connected between adjacent
hoops.
7. The stent according to claim 6, wherein the at least one
flexible link is connected between the loops of adjacent hoops.
8. The stent according to claim 4, wherein the plurality of struts
and the loops define at least one pre-configured cell.
9. The stent according to claim 7, wherein the plurality of struts
and the loops define at least one pre-configured cell.
10. The stent according to claim 9, wherein the plurality of struts
and the loops define at least one partial cell.
11. The stent according to claim 10, wherein the partial cell is
defined when the lattice is in the closed configuration.
12. The stent according to claim 7, wherein the plurality of struts
and the loops define at least one formed cell.
13. The stent according to claim 12, wherein the at least one
formed cell is defined when the lattice is in the open
configuration.
14. The stent according to claim 4, wherein the male end has a
substantially convex configuration.
15. The stent according to claim 14, wherein the female end has a
substantially concave configuration.
16. The stent according to claim 9, wherein the at least one
pre-configured cell has a substantially diamond shape.
17. The stent according to claim 4, wherein the lattice further
comprises a drug coating.
18. The stent according to claim 4, wherein the lattice further
comprises a drug and polymer coating combination.
19. The stent according to claim 17, wherein the drug is
rapamycin.
20. The stent according to claim 18, wherein the drug is
rapamycin.
21. The stent according to claim 17, wherein the drug is
paclitaxel.
22. The stent according to claim 18, wherein the drug is
paclitaxel.
23. The stent according to claim 4, wherein the stent is made of an
alloy.
24. The stent according to claim 23, wherein the stent is made of
stainless steel.
25. The stent according to claim 4, wherein the stent is crush
recoverable.
26. The stent according to claim 25 wherein the stent is made of
nickel titanium (NiTi).
27. The stent according to claim 23, wherein the stent is made of a
super elastic alloy.
28. The stent according to claim 27, wherein the stent is made of
nickel titanium (NiTi).
Description
FIELD OF THE INVENTION
[0001] The present invention relates, in general, to intralumenal
medical devices, and, more particularly, two a new and useful stent
having interlocking elements for stenting a vessel.
BACKGROUND ART
[0002] A stent is commonly used as a tubular structure left inside
the lumen of a duct to relieve an obstruction. Commonly, stents are
inserted into the lumen in a non-expanded form and are then
expanded autonomously (or with the aid of a second device) in situ.
When used in coronary artery procedures for relieving stenosis,
stents are placed percutaneously through the femoral artery. In
this type of procedure, stents are delivered on a catheter and are
either self-expanding or, in the majority of cases, expanded by a
balloon. Self-expanding stents do not need a balloon to be
deployed. Rather the stents are constructed using metals with
spring-like or superelastic properties (i.e., Nitinol), which
inherently exhibit constant radial support. Self-expanding stents
are also often used in vessels close to the skin (i.e., carotid
arteries) or vessels that can experience a lot of movement (i.e.,
popliteal artery). Due to a natural elastic recoil, self-expanding
stents withstand pressure or shifting and maintain their shape.
[0003] As mentioned above, the typical method of expansion for
balloon expanded stents occurs through the use of a catheter
mounted angioplasty balloon, which is inflated within the stenosed
vessel or body passageway, in order to shear and disrupt the
obstructions associated with the wall components of the vessel and
to obtain an enlarged lumen.
[0004] In addition, balloon-expandable stents are available either
pre-mounted or unmounted. A pre-mounted system has the stent
already crimped on a balloon, while an unmounted system gives the
physician the option as to what combination of devices (catheters
and stents) to use. Accordingly, for these types of procedures, the
stent is first introduced into the blood vessel on a balloon
catheter. Then, the balloon is inflated causing the stent to expand
and press against the vessel wall. After expanding the stent, the
balloon is deflated and withdrawn from the vessel together with the
catheter. Once the balloon is withdrawn, the stent stays in place
permanently, holding the vessel open and improving the flow of
blood.
[0005] In the absence of a stent, restenosis may occur as a result
of elastic recoil of the stenotic lesion. Although a number of
stent designs have been reported, these designs have suffered from
a number of limitations. Some of these limitations include design
limitations resulting in low radial strength, decrease in the
length of the stent upon deployment, i.e. foreshortening, and high
degree of axial compression experienced by the stent.
[0006] Accordingly, to date, there have not been any stent designs,
that specifically address these drawbacks in an efficient and cost
effective manner.
SUMMARY OF THE INVENTION
[0007] The present invention relates to an apparatus and method for
stenting a vessel in conjunction with a particular new and useful
stent having a lattice of interconnecting elements defining a
substantially cylindrical configuration. The lattice has a first
open end and a second open end wherein the lattice is movable
between a closed configuration and an open configuration.
[0008] The lattice comprises a plurality of adjacent hoops wherein
each hoop is separated from another hoop in the closed
configuration and each hoop interlocks with another hoop in the
open configuration.
[0009] Each hoop comprises a plurality of loops. And, each hoop
further comprises a plurality of struts connected to the loops.
[0010] At least one loop of one hoop comprises a male end and at
least one loop of another hoop comprises a female end. The male end
is separated from the female end when the lattice is in the closed
configuration. The male end is connectably mated to the female end
when the lattice is moved to the open configuration thereby locking
the stent lattice in the open configuration.
[0011] Thus, the male end of at least one loop of one hoop and the
female end of at least one loop of another hoop form a locked joint
when the lattice is moved into the open configuration thereby
locking the stent in the open configuration. The lattice further
comprises at least one flexible link or a plurality of flexible
links connected between adjacent hoops. The flexible links comprise
various shapes such as a sinusoidal shaped, straight or linear
shape, or a substantially S-shaped or Z-shaped pattern. At least
one flexible link is connected between loops of adjacent hoops of
the lattice.
[0012] Additionally, the plurality of struts and the loops define
at least one pre-configured cell. Preferably, the lattice comprises
a plurality of pre-configured cells defined by the plurality of
struts and the loops of the lattice.
[0013] Additionally, the plurality of struts and the loops also
define at least one partial cell. In a preferred embodiment in
accordance with the present invention, the plurality of struts and
the loops define a plurality of partial cells. A partial cell is
defined by the plurality of struts and the loops when the lattice
is in the closed configuration.
[0014] Additionally, the plurality of struts and the loops define
at least one formed cell. In a preferred embodiment in accordance
with the present invention, the plurality of struts and the loops
of the stent lattice define a plurality of formed cells. A formed
cell is defined by the plurality of struts and the loops when the
lattice is moved into the open configuration (locked
configuration).
[0015] The male end of the at least one loop of one hoop has a
substantially convex configuration. The female end of at least one
loop of another hoop has a substantially concave configuration. In
accordance with the present invention, alternative forms, shapes or
configurations for the male end and female end respectively are
also contemplated herein.
[0016] In accordance with one embodiment of the present invention,
each pre-configured cell has a substantially diamond shape. Other
shapes for the pre-configured cell are also contemplated by the
present invention, and thus, the pre-configured cell may take the
form of any desired shape.
[0017] Additionally, the stent lattice further comprises a drug
coating or a drug and polymer coating combination. In one
embodiment according to the present invention the drug is
rapamycin. In an alternative embodiment in accordance with the
present invention, the drug is paclitaxel. Other drugs and drug
polymer combinations are also contemplated by the present invention
and examples are provided later in this disclosure.
[0018] The stent of the present invention is directed toward both a
balloon actuated stent and a self-expanding stent. The stent is
made of any suitable material. In one embodiment, the stent is made
of an alloy such as stainless steel. In another preferred
embodiment, the stent is made of a nickel titanium (Nitinol) alloy.
Moreover, this material or any other super-elastic alloy is
suitable for the stent according to the present invention. In these
self-expanding stent embodiments, the stent is a crush recoverable
stent.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The novel features of the invention are set forth with
particularity in the appended claims. The invention itself,
however, both as to organization and methods of operation, together
with further objects and advantages thereof, may be best understood
by reference to the following description, taken in conjunction
with the accompanying drawings in which:
[0020] FIG. 1 is a perspective view of a of a stent in a
closed-configuration in accordance with the present invention;
[0021] FIG. 2 is a partial side plan view of the stent of FIG. 1A
in the closed configuration in accordance with the present
invention;
[0022] FIG. 3 is a perspective view of the stent of FIG. 1 in an
open configuration in accordance with the present invention;
[0023] FIG. 4 is a partial side view of the stent of FIG. 1 in the
open configuration in accordance with the present invention;
DETAILED DESCRIPTION OF THE INVENTION
[0024] In FIGS. 1-4, a stent 100 that is an expandable prosthesis
for a body passageway is illustrated. It should be understood that
the terms "stent" and "prosthesis" are interchangeably used to some
extent in describing the present invention, insofar as the method,
apparatus, and structures of the present invention may be utilized
not only in connection with an expandable intraluminal vascular
graft for expanding partially occluded segments of a blood vessel,
duct or body passageways, such as within an organ, but may so be
utilized for many other purposes as an expandable prosthesis for
many other types of body passageways. For example, expandable
prostheses may also be used for such purposes as: (1) supportive
graft placement within blocked arteries opened by transluminal
recanalization, but which are likely to collapse in the absence of
internal support; (2) similar use following catheter passage
through mediastinal and other veins occluded by inoperable cancers;
(3) reinforcement of catheter created intrahepatic communications
between portal and hepatic veins in patients suffering from portal
hypertension; (4) supportive graft placement of narrowing of the
esophagus, the intestine, the ureters, the uretha, etc.; (5)
intraluminally bypassing a defect such as an aneurysm or blockage
within a vessel or organ; and (6) supportive graft reinforcement of
reopened and previously obstructed bile ducts. Accordingly, use of
the term "prosthesis" encompasses the foregoing usages within
various types of body passageways, and the use of the term
"intraluminal graft" encompasses use for expanding the lumen of a
body passageway. Further in this regard, the term "body passageway"
encompasses any lumen or duct within the human body, such as those
previously described, as well as any vein, artery, or blood vessel
within the human vascular system.
[0025] The stent 100 is an expandable lattice structure made of any
suitable material which is compatible with the human body and the
bodily fluids (not shown) with which the stent 100 may come into
contact. The lattice structure is an arrangement of interconnecting
elements made of a material which has the requisite strength and
elasticity characteristics to permit the tubular shaped stent 100
to be moved or expanded from a closed (crimped) position or
configuration shown in FIGS. 1 and 2 to an expanded or open
position or configuration shown in FIGS. 2 and 3. Some examples of
materials that are used for the fabrication of the stent 100
include silver, tantalum, stainless steel, gold, titanium or any
type of plastic material having the requisite characteristics
previously described. Based on the interlocking design of the stent
100 (greater detail provided later in this disclosure), when the
stent 100 is deployed or expanded to its open position, even
materials that tend to recoil to a smaller diameter or exhibit
crushing or deformation-like properties are used for the stent 100
in accordance with the present invention. These are materials that
are not used in traditional (prior art) stent designs. Some
examples of these non-traditional stent materials that are used for
the stent 100 in accordance with the present invention include
deformable plastics, plastics that exhibit crushing or recoil upon
deployment of the stent or polymers such as biodegradable polymers.
Thus, the stent 100 in accordance with the present invention is
also made of these type of plastics or polymers to include
biodegradable polymers. Additionally, the biodegradable polymers
used as material for the stent 100 can be drug eluting polymers
capable of eluting a therapeutic and/or pharmaceutical agent
according to any desired release profile.
[0026] In one embodiment, the stent is fabricated from 316L
stainless steel alloy. In a preferred embodiment, the stent 100
comprises a superelastic alloy such as nickel titanium (NiTi, e.g.,
Nitinol). More preferably, the stent 100 is formed from an alloy
comprising from about 50.5 to 60.0% Ni by atomic weight and the
remainder Ti. Even more preferably, the stent 100 is formed from an
alloy comprising about 55% Ni and about 45% Ti. The stent 100 is
preferably designed such that it is superelastic at body
temperature, and preferably has an Af temperature in the range from
about 24.degree. C. to about 37.degree. C. The superelastic design
of the stent 100 makes it crush recoverable and thus suitable as a
stent or frame for any number of vascular devices for different
applications.
[0027] The stent 100 comprises a tubular configuration formed by a
lattice of interconnecting elements defining a substantially
cylindrical configuration and having front and back open ends 102,
104 and defining a longitudinal axis extending therebetween. In its
closed configuration, the stent 100 has a first diameter for
insertion into a patient and navigation through the vessels and, in
its open configuration, a second diameter, as shown in FIG. 3, for
deployment into the target area of a vessel with the second
diameter being greater than the first diameter. The stent 100
comprises a plurality of adjacent hoops 106a-106h extending between
the front and back ends 102, 104. The stent 100 comprises any
combination or number of hoops 106. The hoops 106a-106h include a
plurality of longitudinally arranged struts 108 and a plurality of
loops 110 connecting adjacent struts 108. Adjacent struts 108 or
loops 110 are connected at opposite ends by flexible links 114
which can be any pattern such as sinusoidal shape, straight
(linear) shape or a substantially S-shaped or Z-shaped pattern. The
plurality of loops 110 have a substantially curved
configuration.
[0028] The flexible links 114 serve as bridges, which connect
adjacent hoops 106a-106h at the struts 108 or loops 110. Each
flexible link comprises two ends wherein one end of each link 114
is attached to one strut 108 or one loop 110 on one hoop 106a and
the other end of the link 114 is attached to one strut 108 or one
loop 110 on an adjacent hoop 106b, etc.
[0029] The above-described geometry better distributes strain
throughout the stent 100, prevents metal to metal contact where the
stent 100 is bent, and minimizes the opening between the features
of the stent 100; namely, struts 108, loops 110 and flexible links
114. The number of and nature of the design of the struts, loops
and flexible links are important design factors when determining
the working properties and fatigue life properties of the stent
100. It was previously thought that in order to improve the
rigidity of the stent, struts should be large, and thus there
should be fewer struts 108 per hoop 106a-106h. However, it is now
known that stents 100 having smaller struts 108 and more struts 108
per hoop 106a-106h improve the construction of the stent 100 and
provide greater rigidity. Preferably, each hoop 106a-106h has
between twenty-four (24) to thirty-six (36) or more struts 108. It
has been determined that a stent having a ratio of number of struts
per hoop to strut length which is greater than four hundred has
increased rigidity over prior art stents which typically have a
ratio of under two hundred. The length of a strut is measured in
its compressed state (closed configuration) parallel to the
longitudinal axis of the stent 100 as illustrated in FIG. 1.
[0030] FIG. 3 illustrates the stent 100 in its open or expanded
state. As may be seen from a comparison between the stent 100
configuration illustrated in FIG. 1 and the stent 100 configuration
illustrated in FIG. 3, the geometry of the stent 100 changes quite
significantly as it is deployed from its unexpanded state (closed
or crimped configuration/position) to its expanded state (open or
expanded configuration/position). As the stent 100 undergoes
diametric change, the strut angle and strain levels in the loops
110 and flexible links 114 are affected. Preferably, all of the
stent features will strain in a predictable manner so that the
stent 100 is reliable and uniform in strength. In addition, it is
preferable to minimize the maximum strain experienced by the struts
108, loops 110 and flexible links 114 since Nitinol properties are
more generally limited by strain rather than by stress. The
embodiment illustrated in FIGS. 1-4 has a design to help minimize
forces such as strain.
[0031] As best illustrated in FIG. 2, the stent 100, in the
closed-configuration (crimped configuration wherein the stent 100
is crimped on the stent delivery device such as a catheter), has a
plurality of pre-configured cells 120a. Each pre-configured cell
120a is defined by the struts 108 and loops 110 connected to each
other respectively thereby defining an open area in the stent
lattice 100. This open area is a space identified as the
pre-configured cell 120a.
[0032] Each hoop 106a-106h has one or more (or a plurality of)
pre-configured cells 120a. In one embodiment according to the
present invention, the pre-configured cell 120a is a diamond-shaped
area or space. However, it is contemplated in accordance with the
present invention that the pre-configured cell 120a take the form
of any desired alternative shape.
[0033] Additionally, the stent lattice 100 also includes at least
one (or a plurality of) partial cells 120b. Each partial cell 120b
is defined by struts 108 and one loop 110 of the respective hoops
106a-106h. In one embodiment according to the present invention,
the partial cell 120b defines a semi-enclosed area or space having
an open end in direct communication with a loop 110 from an
adjacent hoop 106a-106h. In this embodiment according to the
present invention, the flexible link 114 connects adjacent hoops,
for example hoop 106b to hoop 106c, by having one end of flexible
link 114 connected to an inner surface of loop 110 of a partial
cell 120b of the hoop 106b and the opposite end of the flexible
link 114 connected to loop 110 of the adjacent hoop 106c. Thus, in
this embodiment, the flexible link 114 extends from one end of the
partial cell 120b, for instance, of hoop 106b and extends through
the semi-enclosed area of the partial cell 120b and is connected to
loop 110 of the adjacent hoop 106c. In this embodiment according to
the present invention, the flexible links 114 are connected between
adjacent hoops 106a-106h by extension through the partial cells
120b. Additionally, the partial cell 120b is not only a
semi-enclosed area or space defined by struts 108 and one loop 110
of each hoop 106, but the partial cell 120b may take the form of
any desired semi-enclosed shape.
[0034] In this embodiment according to the present invention, each
partial cell 120b of the stent lattice 100 exists while the stent
100 is in its crimped state or closed configuration, i.e. crimped
to the delivery device such as a catheter.
[0035] Moreover, in one embodiment according to the present
invention, each pre-configured cell 120a has one loop 110
terminating in a male end 130 and the other loop defining the
pre-configured cell 120a terminating in a female and 140. Thus, in
this embodiment in accordance with the present invention, the male
end 130 of one loop 110 and the female end 140 of the other loop
110 of the pre-configured cell 120a are positioned opposite each
other thereby defining opposite ends of the pre-configured cell
120a, for example opposite ends of the diamond-shaped area in this
embodiment.
[0036] In one embodiment in accordance with the present invention,
the male end 130 has a substantially convex configuration and the
female end 140 has a substantially concave configuration. In
general, the female end 140 is designed such that it is shaped to
receive and mateably connect with the male end 130. Accordingly, in
this embodiment, the substantially concave surface of the female
end 140 mateably connects with the substantially convex shape of
the male end 130 when the stent lattice 100 is moved to the open
configuration or state (deployed or expanded state) such as shown
in FIGS. 3 and 4.
[0037] As best illustrated in FIG. 4, when the stent lattice 100 is
deployed or expanded to its open position or configuration, the
male end 130 of the loop 110 of one hoop 106, for example 106b,
mateably connects with the female end 140 of an opposite loop 110
of an adjacent hoop, for example 106c, thereby forming a locked
joint 150. The male end 130 and the female end 140 may take the
form of any desired shape or configuration that permits the male
end 130 to mateably connect with the female end 140 in order to
form the locked joint 150. For example, the male end 130 and the
female end 140 may be shaped respectively in order to form portions
of a dove-tail such that the locked joint 150 has or forms a
dove-tail configuration. Other shapes for the male end 130 and
female end 140 forming the locked joint 150 are also contemplated
herein.
[0038] Accordingly, when the stent lattice 100 is deployed or
expanded to the open position (open configuration of the stent
100), adjacent hoops 106a-106h interlock with each other at the
newly formed joints 150 mateably connecting adjacent hoops
106a-106h. For example, when the stent lattice 100 is moved to its
open configuration, the hoop 106b mateably connects or interlocks
with the adjacent hoop 106c and the hoop 106c interlocks with the
adjacent hoop 106d, etc. Thus, the points of interlocking or
mateable connection are located at the newly formed locked joint
150 between each pair of adjacent hoops 106 as shown. Thus, each
locked joint 150 is formed by at least one loop 110 of one hoop 106
(for example 106b, wherein the male end 130 of this loop 110
mateably connects with the female end 140 of another loop 110),
i.e. an adjacent loop on an adjacent hoop 106, for example loop 110
on the hoop 106c which is directly opposed from the male end 130 of
loop 110 of the hoop 106b. Therefore, the adjacent hoops 106a-106h,
are mateably connected to or locked to each other respectively at
each locked joint 150 formed in a manner such as described
above.
[0039] Upon the mateable connection or linking of the male end 130
to the female end 140 (on the loops 110 of adjacent hoops 106), a
formed cell 120c is created or formed between adjacent locked
joints 150 form by a pair of interlocking, adjacent hoops 106, for
example, 106a and 106b, etc. Each formed cell 120c is a fully
enclosed area or space defined by the struts 108 loops 110 and
locked joints 150 formed by the adjacent hoops 106, i.e. linking of
hoop 106a to hoop 106b, linking of hoop 106b to adjacent hoop 106c,
etc. Accordingly, the partial cell 120b (FIG. 2) of the stent
lattice 100 in its crimped configuration, becomes the formed cell
120c when linked or coupled by the locked joint 150 between
adjacent hoops 106 as shown in FIG. 4.
[0040] In accordance with the present invention, the stent 100 has
flexible links 110 that may be on one or more of the following
components of the stent lattice: the hoops 106a-106h, the loops
110, and/or the struts 108. Moreover, the components of the stent
lattice, i.e. hoops, loops, struts and flexible links, have drug
coatings or drug and polymer coating combinations that are used to
deliver drugs, i.e. therapeutic and/or pharmaceutical agents
including: antiproliferative/antimitotic agents including natural
products such as vinca alkaloids (i.e. vinblastine, vincristine,
and vinorelbine), paclitaxel, epidipodophyllotoxins (i.e.
etoposide, teniposide), antibiotics (dactinomycin (actinomycin D)
daunorubicin, doxorubicin and idarubicin), anthracyclines,
mitoxantrone, bleomycins, plicamycin (mithramycin) and mitomycin,
enzymes (L-asparaginase which systemically metabolizes L-asparagine
and deprives cells which do not have the capacity to synthesize
their own asparagine); antiplatelet agents such as
G(GP)II.sub.bIII.sub.a inhibitors and vitronectin receptor
antagonists; antiproliferative/antimitotic alkylating agents such
as nitrogen mustards (mechlorethamine, cyclophosphamide and
analogs, melphalan, chlorambucil), ethylenimines and
methylmelamines (hexamethylmelamine and thiotepa), alkyl
sulfonates-busulfan, nirtosoureas (carmustine (BCNU) and analogs,
streptozocin), trazenes-dacarbazinine (DTIC);
antiproliferative/antimitot- ic antimetabolites such as folic acid
analogs (methotrexate), pyrimidine analogs (fluorouracil,
floxuridine, and cytarabine), purine analogs and related inhibitors
(mercaptopurine, thioguanine, pentostatin and
2-chlorodeoxyadenosine {cladribine}); platinum coordination
complexes (cisplatin, carboplatin), procarbazine, hydroxyurea,
mitotane, aminoglutethimide; hormones (i.e. estrogen);
anticoagulants (heparin, synthetic heparin salts and other
inhibitors of thrombin); fibrinolytic agents (such as tissue
plasminogen activator, streptokinase and urokinase), aspirin,
dipyridamole, ticlopidine, clopidogrel, abciximab; antimigratory;
antisecretory (breveldin); antiinflammatory: such as adrenocortical
steroids (cortisol, cortisone, fludrocortisone, prednisone,
prednisolone, 6.alpha.-methylprednisolone, triamcinolone,
betamethasone, and dexamethasone), non-steroidal agents (salicylic
acid derivatives i.e. aspirin; para-aminophenol derivatives i.e.
acetominophen; indole and indene acetic acids (indomethacin,
sulindac, and etodalac), heteroaryl acetic acids (tolmetin,
diclofenac, and ketorolac), arylpropionic acids (ibuprofen and
derivatives), anthranilic acids (mefenamic acid, and meclofenamic
acid), enolic acids (piroxicam, tenoxicam, phenylbutazone, and
oxyphenthatrazone), nabumetone, gold compounds (auranofin,
aurothioglucose, gold sodium thiomalate); immunosuppressives:
(cyclosporine, tacrolimus (FK-506), sirolimus (rapamycin),
azathioprine, mycophenolate mofetil); angiogenic agents: vascular
endothelial growth factor (VEGF), fibroblast growth factor (FGF)
platelet derived growth factor (PDGF), erythropoetin,; angiotensin
receptor blocker; nitric oxide donors; anti-sense oligionucleotides
and combinations thereof, cell cycle inhibitors, mTOR inhibitors,
and growth factor signal transduction kinase inhibitors. It is
important to note that one or more of the lattice components (e.g.
hoops, loops, struts and flexible links) are coated with one or
more of the drug coatings or drug and polymer coating combinations.
Additionally, as mentioned above, the stent 100 is alternatively
made of a polymer material itself such as a biodegradable material
capable of containing and eluting one or more drugs, in any
combination, in accordance with a specific or desired drug release
profile.
[0041] The method of utilizing the stent 100 according to the
present invention includes first identifying a location, for
example, a site within the vessel in a patient's body for
deployment of the stent 100. Upon identifying the desired
deployment location, for example a stenotic lesion or vulnerable
plaque site, a delivery device, such as a catheter carrying the
stent 100 crimped to a distal end of the catheter such that the
stent 100 is in its closed configuration, is inserted within the
vessel in the patient's body. The catheter is used to traverse the
vessel until reaching the desired location (site) wherein the
distal end of the catheter is positioned at the desired location
(site), for instance the lesion, within the vessel. At this point,
the stent 100 is deployed to its open configuration by expanding
the stent 100 such as by inflation if the stent 100 is a balloon
expandable stent or by uncovering or release of the stent 100 if
the stent 100 is a self-expanding (crush recoverable) type stent.
If a cover is utilized to further protect and secure the stent 100
to the catheter distal end when the stent 100 is a self-expanding
stent, the cover is removed from the distal end of the catheter
prior to expansion of the stent 100, for instance, through use of
an expandable member such as an inflatable balloon.
[0042] Upon expanding the stent 100 to its open configuration, the
expandable member (balloon) is then collapsed, for instance through
deflation of the expandable member, whereby the catheter is removed
from the deployment site of the vessel and patient's body
altogether.
[0043] As mentioned previously, the unique design of the stent 100,
i.e. the interlocking of adjacent hoops 106 upon deployment of the
stent 100, allows for a wide array of materials, not previously
used with prior art stents, to be used with the stent 100 in
accordance with the present invention. These include materials
normally prone to crushing, deformation or recoil upon deployment
of the stent. These materials include plastics and polymers to
include biodegradable polymers such as drug eluting polymers.
[0044] While preferred embodiments of the present invention have
been shown and described herein, it will be obvious to those
skilled in the art that such embodiments are provided by way of
example only. Numerous variations, changes, and substitutions will
now occur to those skilled in the art without departing from the
invention. Accordingly, it is intended that the invention be
limited only by the spirit and scope of the appended claims.
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