U.S. patent application number 10/746452 was filed with the patent office on 2004-09-30 for multiple joint implant delivery systems for sequentially-controlled implant deployment.
This patent application is currently assigned to CardioMind, Inc.. Invention is credited to Nikolchev, Julian.
Application Number | 20040193178 10/746452 |
Document ID | / |
Family ID | 32996025 |
Filed Date | 2004-09-30 |
United States Patent
Application |
20040193178 |
Kind Code |
A1 |
Nikolchev, Julian |
September 30, 2004 |
Multiple joint implant delivery systems for sequentially-controlled
implant deployment
Abstract
The invention provides an atraumatic, low profile device for the
delivery of one or more implants into tubular organs or open
regions of the body. The implant delivery device may simultaneously
or independently release portions of the implant, e.g., the
proximal and distal ends of the implant. This independent release
feature allows better implant positioning at the target site. Upon
deployment, the implants may be placed at the target site without a
sheath.
Inventors: |
Nikolchev, Julian; (Portola
Valley, CA) |
Correspondence
Address: |
BOZICEVIC, FIELD & FRANCIS LLP
200 MIDDLEFIELD RD
SUITE 200
MENLO PARK
CA
94025
US
|
Assignee: |
CardioMind, Inc.
|
Family ID: |
32996025 |
Appl. No.: |
10/746452 |
Filed: |
December 24, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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60458323 |
Mar 26, 2003 |
|
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60462219 |
Apr 10, 2003 |
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Current U.S.
Class: |
606/108 |
Current CPC
Class: |
A61B 17/1214 20130101;
A61B 17/12109 20130101; A61F 2002/9505 20130101; A61B 17/12022
20130101; A61F 2002/9511 20130101; A61B 17/12136 20130101; A61B
2017/00867 20130101; A61B 2017/12063 20130101; A61F 2/95 20130101;
A61B 90/39 20160201; A61B 2017/1205 20130101 |
Class at
Publication: |
606/108 |
International
Class: |
A61B 017/00 |
Claims
1.-21. (Cancelled, without prejudice)
22. The system of claim 24 wherein the implant exterior surface is
smooth after deployment.
23. The system of claim 24 wherein the implant interior surface is
smooth after deployment.
24. A implant delivery system comprising: an elongate delivery
guide member having a proximal end and a distal end, the delivery
guide member configured to direct at least one implant having an
exterior and interior surface to an anatomical treatment site by
manipulation by a user, the at least one implant having a delivery
diameter prior to release of the at least one implant and located
proximally of the distal end of the delivery guide member prior to
release, and a plurality of releasable joints, each joint
configured to maintain a section of the at least one implant at the
delivery diameter until release of the releasable joints, wherein
the system is adapted for sequential release of the releasable
joints.
25. The system of claim 24 wherein the delivery guide member is
closed at its distal end.
26. The system of claim 24 wherein the delivery guide member has a
diameter distally and proximally of the at least one implant that
is substantially equal to the at least one implant delivery
diameter, whereby a substantially atraumatic implant delivery
system is provided.
27. The system of claim 24 wherein the delivery guide member has no
passageway from its proximal to its distal end.
28. The system of claim 24 further comprising an actuator for
releasing the releasable joints, and wherein the delivery guide
member has only a single passageway from its proximal to its distal
end, that passageway contains the actuator, and that actuator does
not extend beyond the distal end of the delivery guide member.
29. The system of claim 28 wherein the actuator for releasing the
releasable joints is affixed to the distal end of the delivery
guide member.
30. The system of claim 24 wherein the at least one implant
comprises exactly one implant.
31. The system of claim 24 wherein the at least one implant
comprises more than one implant.
32. The system of claim 24 wherein the delivery guide member
comprises a distal guide section and a proximal guide section and a
gap between the distal guide section and the proximal guide section
and the at least one implant is located between the distal guide
section and the proximal guide section.
33. (Cancelled, without prejudice)
34. The system of claim 24 wherein the delivery guide member is
tubular in form, having a lumen therein.
35. The system of claim 34 further comprising an actuator slidably
located at least partially within the delivery guide member lumen
and configured to release at least one releasable joint upon axial
movement within the delivery guide member.
36, 37. (Cancelled, without prejudice).
38. The system of claim 34 further comprising an actuator slidably
located at least partially within the delivery guide member lumen
and configured to release at least one releasable joint upon
rotational movement within the delivery guide member.
39. The system of claim 34 wherein at least one releasable joint is
configured to release upon application of fluid pressure in the
delivery guide member lumen and further comprising a fluid director
slidably located at least partially within the delivery guide
member lumen and configured to direct fluid to and to release that
selected at least one releasable joint.
40. The system of claim 39 wherein the fluid director is configured
to sequentially release the plurality of releasable joints upon
application of fluid pressure in the delivery guide member
lumen.
41. The system of claim 34 wherein the releasable joints are
configured to release upon application of a suitable DC current to
the releasable joints, the system further comprising an electrical
conductor located at least partially within the delivery guide
member lumen to supply the suitable DC current to and to thereby
release at the releasable joints.
42, 43. (Cancelled, without prejudice)
44. The system of claim 24 wherein the implant is a stent.
45. The system of claim 44 wherein the stent is unsheathed.
46. The system of claim 24 wherein the implant is an occlusive
coil.
47. The system of claim 24 wherein the implant further comprises a
therapeutic agent.
48. The system of claim 47 wherein the therapeutic agent is
selected from the group consisting of antibiotics, anticoagulants,
antifungal agents, anti-inflammatory agents, antineoplastic agents,
antithrombotic agents, endothelialization promoting agents, free
radical scavengers, immunosuppressive agents, thrombolytic agents,
and combinations thereof.
49. The system of claim 24 wherein the delivery guide member
further comprises a radioopaque marker.
50. The system of claim 24 having flexibility and remote
directability, wherein the remote directability is such that a user
may direct the distal end of the delivery guide member into and
introduce the at least one implant into a coronary artery solely by
manipulation of the delivery guide member from its proximal
end.
51.-75. (Cancelled, without prejudice)
76. A system for treating a target site in a tubular organ
comprising: the implant delivery system of any one of claims 22-32,
34, 35, 38-41 or 44-50; and a balloon catheter.
77. The system of claim 76 further comprising an embolic
filter.
78. The system of claim 77 wherein the embolic filter is attached
to the proximal end of the delivery guide member.
79. The system of claim 76 wherein the implant is a stent.
80. The system of claim 76 wherein the implant is an occlusive
coil.
81. A method for delivering an implant in a subject comprising:
accessing a body region; advancing an implant delivery guide to a
target site in the body region; and releasing the implant at the
target site by releasing one portion of the implant after another
in a sequential fashion.
82. The method of claim 81 further comprising deploying at least
one embolic filter.
83. The method of claim 81 wherein the releasing comprises
releasing a distal end of the implant from the delivery guide
before releasing a proximal end of the implant from the delivery
guide.
84. The method of claim 81 wherein the releasing comprises a
mechanical detachment process.
85. The method of claim 81 wherein the releasing comprises a
hydraulic detachment process.
86. The method of claim 81 wherein the releasing comprises an
electrolytic detachment process.
87. The method of claim 81 wherein the body region is a tubular or
hollow organ.
88. The method of claim 87 wherein the tubular or hollow organ is
selected from the group consisting of blood vessels, arteriovenous
malformations, aneurysms, arteriovenous fistulas, cardiac chambers,
bile ducts, mammary ducts, fallopian tubes, ureters, large and
small airways, stomach, intestines, and bladder.
89. The method of claim 81 wherein the body region is a blood
vessel.
90. The method of claim 81 wherein the implant is a stent.
91. The method of claim 81 wherein the implant is an occlusive
coil.
92. The method of claim 81 wherein the target site comprises an
aneurysm.
93. The method of claim 81 wherein the subject is human.
94. The method of claim 81 wherein the accessing is performed
percutaneously.
95. The method of claim 81 wherein the stent implant delivery
system is selected from those described in any one of claims 22-32,
34, 35, 38-41, 44-50 or 76-80.
96. The method of claim 81 further comprising: advancing a balloon
catheter to the target site; performing angioplasty with the
balloon catheter prior to the releasing of the implant.
97. The system of claim 25, wherein an atraumatic tip provides the
end closure
98. The system of claim 24 wherein the delivery guide member has a
distal diameter between about 0.010 and about 0.020 inches, whereby
a low-profile delivery system is provided.
99. The system of claim 24 wherein the delivery guide member is
noninflatable.
100. The system of claim 24 wherein the system is
guidewireless.
101. The system of claim 25, wherein an atraumatic tip provides the
end closure
Description
FIELD OF THE INVENTION
[0001] This invention relates to devices and methods for placing
one or more implants such as helical scaffolds or occlusive members
into tubular organs or open regions of the body. The implants may
be of types that maintain patency of an open anatomical structure,
occlude a selected volume, isolate a region, or collect other
occlusive members at a site. Included in the description are
devices and methods for deploying the various implants, typically
without a sheath, in a serial fashion, and with high
adjustibility.
BACKGROUND OF THE INVENTION
[0002] Implants such as stents and occlusive coils have been used
in patients for a wide variety of reasons. For instance, stents are
often used to treat arterial stenosis secondary to atherosclerosis.
Various stent designs have been developed and used clinically, but
self-expandable and balloon-expandable stent systems and their
related deployment techniques are now predominant. Examples of
self-expandable stents currently in use are WALLSTENT.RTM. stents
(Schneider Peripheral Division, Minneapolis, Minn.) and Gianturco
stents (Cook, Inc., Bloomington, Ind.). The most commonly used
balloon-expandable stent is the PALMAZ.RTM. stent (Cordis
Corporation, Warren, N.J.).
[0003] Typically, after balloon angioplasty has been performed,
either a self-expandable or balloon-expandable stent is advanced
over a guidewire and positioned at the target site. A protective
sheath or membrane is then retracted proximally to allow expansion
of a self-expanding stent. Alternatively, a delivery balloon may be
inflated, thereby expanding the stent.
[0004] Despite improvements in delivery systems, balloon design,
and stent design, these over-the-guidewire and/or sheathed
self-expanding stent deployment systems still have their
limitations. For instance, sheathed stents tend to move forward
when the sheath is pulled back, deploying them imprecisely. The
sheathed design also requires that the stent delivery system be
larger in diameter and less flexible. Furthermore, for sheathed
systems, the interventional procedure may only proceed if the
vessel of interest is of sufficiently large diameter to allow
sheath placement to avoid significant damage to the luminal surface
of the vessel. Moreover, balloon-expandable stents, by virtue of a
large diameter and relative inflexibility, are often unable to
reach distal vasculature. For both self-expandable and
balloon-expandable stent deployment systems, repositioning or
step-wise release of the stent are usually not available features.
Similarly, occlusive coil placement systems such as systems that
deliver detachable platinum coils and GDC.RTM. coils also generally
do not contain repositionable or step-wise release features.
[0005] Consequently, a smaller diameter (lower profile),
repositionable implant deployment device that releases an implant
into, or upon, a body region in a more precise, continuous or
step-wise fashion, without the use of a sheath or balloon would
provide significant benefit to patients with various medical
conditions.
SUMMARY OF THE INVENTION
[0006] The present invention is a low profile implant delivery
device that may be deployed without a sheath, and is designed to
release portions of implants simultaneously or sequentially.
[0007] In one variation, the implant delivery device includes a
noninflatable, elongate delivery guide member having a distal end
and configuration that allows it to direct at least one implant
having an exterior and interior surface to an anatomical treatment
site by manipulation by a user. The at least one implant has a
delivery diameter prior to its release, is located proximally of
the distal end of the delivery guide member prior to release, and
has at least one releasable joint configured to maintain at least a
section of the at least one implant at the delivery diameter until
release of the at least one releasable joint. The delivery guide
member sections that are proximal and distal to the at least one
implant also have delivery diameters. These guide member delivery
diameters may be substantially equal to the at least one implant
delivery diameter prior to implant release.
[0008] The implant may be a helical scaffold, e.g., a stent, in
particular, a self-expandable stent, or it may be an occlusive
coil. The implant may be symmetric or asymmetric. In some
instances, the implant delivers a therapeutic agent.
[0009] The delivery guide member may include a wire and/or a
tubular member having a lumen. If desired, a radioopaque marker may
be included on the delivery guide to aid with its placement. When
designed to include a tubular member, it co-axially surrounds at
least a portion of the delivery guide, and works as a tubular
actuator configured to release at least one releasable joint upon
distal axial movement along the delivery guide member.
[0010] In another variation, the implant delivery device includes
an actuator slidably located at least partially within the delivery
guide member and is configured to mechanically release at least one
releasable joint upon axial movement of the actuator within the
delivery guide member. In other variations, the actuator may also
release at least one releasable joint upon rotational movement of
the actuator, upon the application of fluid pressure in the
delivery guide member lumen, or upon application of a suitable DC
current to the at least one releasable joint. Release of the
releasable joints using any one of the release mechanisms described
above may be sequential, if precise positioning is required, or may
be simultaneous. Each feature of each variation may be used on any
of the other variations.
[0011] The implant delivery device may be included in a system for
implant delivery which further employs one or more embolic filters
at either the proximal or distal section of the delivery guide, or
at both the proximal and distal sections of the delivery guide.
[0012] The system may be used for implant delivery into lumens of
tubular organs including, but not limited to, blood vessels
(including intracranial vessels, large vessels, peripheral vessels,
adjacent aneurysms, arteriovenous malformations, arteriovenous
fistulas), ureters, bile ducts, fallopian tubes, cardiac chambers,
ducts such as bile ducts and mammary ducts, large and small
airways, and hollow organs, e.g., stomach, intestines, and bladder.
The implant may be of a design that is of a size that is smaller
during delivery and larger after implantation. The design may be
used to provide or to maintain patency in an open region of an
anatomical structure, or to occlude a site, or to isolate a region
(e.g., to close an aneurysm by blocking the aneurysm opening or
neck by placement in an adjacent anatomical structure such as an
artery or gastrointesinal tubular member), or to corral or collect
a number of occlusive devices (e.g., coils or hydratable polymeric
noodles) or compositions at a site to be occluded or supported. In
another variation, the implant is located in a gap between proximal
and distal sections of the delivery guide member. The system may
also be employed for implant delivery into solid organs or tissues
including, but not limited to, skin, muscle, fat, brain, liver,
kidneys, spleen, and benign and malignant tumors. Preferably, the
implant is delivered to a target site in a blood vessel lumen.
[0013] In a general aspect, the system is a guidewire-less implant
delivery system that includes a noninflatable, elongate delivery
guide member having a proximal end and a distal end. The guide
member is configured to direct at least one implant having an
exterior and interior surface to an anatomical treatment site by
manipulation by a user. The at least one implant has a delivery
diameter prior to release of the at least one implant and is
located proximally of the distal end of the delivery guide member
prior to release. The at least one releasable joint is configured
to maintain at least a section of the at least one implant at the
delivery diameter until release of the at least one releasable
joint. The guidewire-less system also has a flexibility and remote
directability such that a user may direct the distal end of the
guide member into, and introduce, the at least one implant into a
coronary artery solely by manipulation of the delivery guide member
from its proximal end.
BRIEF DESCRIPTION OF THE DRAWING(S)
[0014] FIG. 1A is a side view of an implant delivery device with a
partial cross-section of the distal section of the delivery
guide.
[0015] FIG. 1B is a cross-sectional view of the delivery guide and
implant taken at line 1B-1B in FIG. 1A.
[0016] FIG. 2 is a side view of an implant delivery device having a
tubular member (actuator) attached to the proximal implant end with
a partial cross-section of the distal section of the delivery
guide.
[0017] FIG. 3A is a side:view of the implant in FIG. 2 being
expanded by distally moving the tubular member towards the distal
section of the delivery guide.
[0018] FIG. 3B is a longitudinal cross-sectional view of a distal
implant release mechanism.
[0019] FIGS. 3C.sub.1 and 3C.sub.2 are longitudinal cross-sectional
views of an implant delivery device having a mechanical release
mechanism for deploying one end of an implant.
[0020] FIGS. 3D.sub.1-3D.sub.3 are longitudinal cross-sectional
views of an implant delivery device having a mechanical release
mechanism for independently releasing the implant ends.
[0021] FIGS. 3E.sub.1-3E.sub.4 are longitudinal cross-sectional
views of an implant delivery device having a hydraulic release
mechanism for independently releasing the implant ends.
[0022] FIGS. 3F.sub.1-3F.sub.2 are longitudinal cross-sectional
views of a variation of the hydraulic release mechanism described
in 3E.sub.1-3E.sub.4.
[0023] FIGS. 3G.sub.1-3G.sub.3 are longitudinal cross-sectional
views of an implant delivery device having a mechanical release
mechanism according to another variation of the invention.
[0024] FIG. 4 is a longitudinal cross-sectional view of an implant
delivery device having a mechanical release mechanism according to
yet another variation of the invention.
[0025] FIGS. 5A-5C are longitudinal cross-sectional views of an
implant delivery device having an electrolytic implant release
mechanism.
[0026] FIG. 5D shows a longitudinal cross-sectional view of an
implant delivery device having an electrolytic release mechanism
according to another variation of the invention.
[0027] FIG. 5E shows a longitudinal cross-sectional view of an
implant delivery device having a thermal release mechanism
according to one variation of the invention.
[0028] FIGS. 6A-6D show the general method for serially releasing
an implant at a target site.
DETAILED DESCRIPTION OF THE INVENTION
[0029] Described here are devices, systems, and methods for
delivering implants into both open and solid regions of the body.
The term "region" as used herein refers to luminal structures as
well as solid organs and solid tissues of the body, whether in
their diseased or nondiseased state. Examples of luminal structures
include, but are not limited to, blood vessels, arteriovenous
malformations, aneurysms, arteriovenous fistulas, cardiac chambers,
ducts such as bile ducts and mammary ducts, fallopian tubes,
ureters, large and small airways, and hollow organs, e.g., stomach,
intestines, and bladder. Solid organs or tissues include, but are
not limited to, skin, muscle, fat, brain, liver, kidneys, spleen,
and benign and malignant tumors.
[0030] The device assembly generally includes an elongate, perhaps
solid delivery guide, an implant, and one or more implant release
mechanisms. Guidewire-less systems are used to deliver the one or
more implants. By "guidewire-less" it is meant that the system does
not require a guiding device of a diameter less than that of the
guide member upon which the implant is delivered to reach a chosen
implantation site. Instead, the guidewire-less system is flexible
and remotely directable, the remote directability being such that a
user may direct the distal end of the guide member into, and
introduce, the at least one implant into a coronary artery solely
by manipulation of the delivery guide member from its proximal
end.
Delivery Guide or Delivery Guide Member
[0031] The delivery guide is elongate and has a comparatively small
effective diameter. It has the function of permitting delivery of
the implant to a selected site and supporting the implant in a
collapsed form during positioning and implantation. The delivery
guide is usually noninflatable. It may also be solid, or may have a
lumen extending therethrough, depending on such factors as the
degree of flexibility required, type of associated release
mechanism, the constitution material, and the like. The tip of the
delivery guide may be tapered and/or straight, curved, or j-shaped,
depending on factors such as physician preference, the anatomy of
the tubular organ or region of interest, degree of stiffness
required, and the like. The delivery guide may or may not include
an outer spring coil, for, e.g., fluoroscopic visualization.
[0032] The delivery guide member and the delivery system into which
it is placed desirably serves the function as would a guidewire in,
for instance, a cardiac or neurovascular catheterization procedure.
The concept that the delivery guide member or system including that
guide member and implant(s) is "remotely directable" is to say that
the combination of physical parameters of the delivery guide
member, implant, and joints are selected to allow advancement of
the system much in the same way as would be a guidewire. Such
physical parameters include, for instance, choice of materials,
stiffness, size of materials, physical or chemical treatment,
tapering (if desired), all in the same way that those physical
parameters are selected in designing a cardiovascular or
neurovascular guidewire.
[0033] The delivery guide may be made from any biocompatible
material including, but not limited to, stainless steel and any of
its alloys; titanium alloys, e.g., nickel-titanium alloys; other
shape memory alloys; tantalum; polymers, e.g., polyethylene and
copolymers thereof, polyethylene terephthalate or copolymers
thereof, nylon, silicone, polyurethanes, fluoropolymers, poly
(vinylchloride), and combinations thereof. The diameter of the
delivery guide may usually be about 0.013 cm to about 0.130 cm
(about 0.005 inches to about 0.05 inches), more usually about 0.013
cm to about 0.076 cm (about 0.005 inches to about 0.03 inches), and
more usually still about 0.015 cm to about 0.030 cm (about 0.006
inches to about 0.012 inches). In a preferred variation, the
diameter of the delivery guide is approximately about 0.020 cm
(about 0.008 inches).
[0034] A lubricious coating may be placed on the delivery guide if
desired to facilitate advancement of the delivery guide. The
lubricious coating typically will include hydrophilic polymers such
as polyvinylpyrrolidone-based compositions, fluoropolymers such as
tetrafluoroethylene, or silicones. In one variation, the lubricious
coating may constitute a hydrophilic gel. Furthermore, the delivery
guide may include one or more radioopaque markers that indicates
the location of the distal section of the delivery guide upon
radiographic imaging. Usually, the marker will be detected by
fluoroscopy.
Implants
[0035] The implant itself may be of a shape tailored to achieve a
specific purpose. As noted elsewhere, if the purpose of the implant
is to provide or to maintain patency of an anatomical structure
such as an artery or duct, the implant shape after implantation is
itself tubular. The shape may be symmetric or asymmetric, as the
purpose dictates.
[0036] Other shapes, including cage structures, may be used to
provide patency to vessels or to act as collecting or coralling
structures for occlusive members or materials.
[0037] If the purpose or task is to occlude a lumen or open region,
the implant may have the form of an occlusive coil that remains
helical after deployment or assumes a random orientation.
[0038] In one variation, the implant for placement into a luminal
structure is a helical scaffold, e.g., a stent, but any scaffold
shape that maintains patency of a lumen may be used. The stents are
typically self-expanding stents, such as described in U.S. Pat. No.
4,768,507 to Fishell et al., U.S. Pat. No. 4,990,155 to Wilkoffet
al., and U.S. Pat. No. 4,553,545 to Maass et al. In another
variation, the implant is an occlusive member, e.g., an occlusive
coil, such as described in U.S. Pat. No. 5,334,210 to Gianturco and
U.S. Pat. No. 5,382,259 to Phelps et al.
[0039] The interior and exterior surfaces of the implant may be
designed to prevent the activation of pathological processes during
or after implant deployment. For example, in the case of a vascular
stent, the exterior stent surface may be formed to be smooth to
decrease the likelihood of intimal damage upon stent release (which
would trigger the inflammatory process and attract atheromatous
plaque-forming cells). The interior stent surface may also be
smooth to minimize turbulent flow through the stent and decrease
the risk of stent thrombosis.
[0040] Important physical properties of the implant to consider
include, but are not limited to: length, (stent) diameter in the
expanded state, degree of flexibility and lateral stiffness, and
the like. These physical properties will be modified to account for
such factors as lumen diameter, length of any stenosis, type of
luminal structure, or solid organ or tissue involved.
[0041] Metals such as stainless steel and tantalum, or metal alloys
such as alloys of nickel and titanium, specifically including
superelastic alloys such as NITINOL or Elgiloy which are commonly
used by those of skill in the art, may be used to form the
implants. However, the implants may also be made from biodegradable
polymers, e.g., copolymers of lactic and glycolic acid, or
nonbiodegradable polymers, e.g., copolymers of ethylene and vinyl
acetate.
[0042] The implants may also include a therapeutic agent. Examples
of therapeutic agents that may be used in the implants include, but
are not limited to, antibiotics, anticoagulants, antifungal agents,
anti-inflammatory agents, antineoplastic agents, antithrombotic
agents, endothelialization promoting agents, free radical
scavengers, immunosuppressive agents, thrombolytic agents, and any
combination thereof. If the implant is a stent, an antithrombotic
agent is preferably included.
[0043] Examples of selective antithrombotic agents include
acetylsalicylic acid, argatroban, cilostazol, copidogrel,
cloricromen, dalteparin, daltroban, defibrotide, dipyridamole,
enoxaparin, epoprostenol, indobufen, iloprost, integrelin,
isbogrel, lamifiban, lamoparan, nadroparin, ozagrel, picotamide,
plafibride, reviparin sodium, ridogrel, sulfinpyrazone, taprostene,
ticlopidine, tinzaparin, tirofiban, triflusal, and any of their
derivatives.
[0044] The therapeutic agent may be coated onto the implant, mixed
with a biodegradable polymer or other suitable temporary carrier
and then coated onto the implant, or, when the implant is made from
a polymeric material, dispersed throughout the polymer.
[0045] The implant may include a radioactive material. The
radioactive material may be selected on the basis of its use. For
instance, the material may be included in an implant where the
implant is in the form of a stent that is to be situated over a
vascular stenosis. The radioactivity lowers the incidence of
re-stenosis. Additionally, the radioactivity may serve the function
of a tracer, to allow detection of the location of the implant
during the procedure or anytime thereafter. Suitable radioactive
tracers include isotopes of gallium, iodine, technetium, and
thallium.
Release Mechanism
[0046] In one variation of the generic implant delivery system, as
shown in FIG. 1A, the implant delivery system includes a delivery
guide 100. Delivery guide 100 has a proximal section 102 and a
distal section 104. An implant, in this case depicted as a stent
106, surrounds a portion of the distal section 104 of the delivery
guide, and is releasably attached to the distal section 104 of the
delivery guide. The implant 106, as shown in FIG. 11B, is
concentrically adjacent to the delivery guide 100. Although I show
the stent in FIGS. 1A and 1B as the implant (106), I depict it in
this fashion solely for the illustrative purpose of indicating the
siting of the implant 106 on the delivery guide 100 with the distal
and proximal implant release mechanism (109, 111). Various implant
release mechanisms or structures are discussed in greater detail
below.
[0047] Implant 106 is shown to be directly attached to, is
contiguous to, the delivery guide 100 at the proximal end 108 of
the implant and distal end 110 of the implant. In the system shown
in FIG. 1A, implant 106 may be secured to the delivery guide 100 by
such generic controllably releasable mechanisms as mechanical,
thermal, hydraulic, and electrolytic mechanisms, or a combination
thereof. Examples of these release mechanisms will be discussed
below.
[0048] Consequently, release of the implant 106 from the delivery
guide 100 may be achieved through a mechanical detachment process
involving, e.g., twisting of the delivery guide, such as described
by Amplatz in U.S. Pat. No. 6,468,301, or translational movement of
the delivery guide in relation to the implant. Implant release may
also be achieved using a thermally detachable joint, such as
described in U.S. Pat. No. 5,108,407 to Geremia et al., an
electrolytic detachable joint, such as described in U.S. Pat. Nos.
5,122,136 and 5,354,295, both to Gulglielmi et al., or a
combination thereof.
[0049] In another variation, and as shown in FIG. 2, the system
includes a tubular member 200 co-axially mounted on a delivery
guide 202. Tubular member 200 may form a component of the delivery
guide 202 that cooperates with one or more of the releasable
mentioned joints on the implant (209, 211) to release those joints
(and therefore, release the implant 204) upon application of a
releasing movement, axial or twisting. An implant, e.g., a stent
204, is mounted on a distal section 206 of the delivery guide and
the distal end 208 of the tubular member is attached to the
proximal end 210 of the stent. The distal end 212 of the stent is
attached using a releasable joint 211 to the distal section 206 of
the delivery guide 202.
[0050] As mentioned above, I may use a tubular member mounted
coaxially about the delivery guide, that slides axially about that
delivery guide, as a actuator to release the implant. The outer
tubular member may also be used to pre-position the implant. For
instance, prior to release, the outer tubular member may be used to
expand the implant to therefore obscure its placement, and so to
permit adjustment of the placement. FIG. 3A shows a stent 300
expanding as tubular member 302 is moved distally on the delivery
guide 304, in the direction of the arrow. The stent is then
released from the delivery guide. Specifically, the distal end 306
of the stent is released from a distal section 308 of the delivery
guide, followed by release of the proximal end 310 of the stent
from the distal end 312 of the tubular member. As mentioned above,
the stent 300 may be secured to a distal section 308 of the
delivery guide by such mechanisms as lock and key arrangements,
biocompatible adhesives, soldering, or a combination thereof.
Consequently, stent release may be achieved through a mechanical
detachment process, a thermal detachment process (e.g., by heat
produced from an exothermic reaction), an electrolytic detachment
process, or a combination thereof.
[0051] FIGS. 3B and 3C show yet another variation of a stent
release mechanism. In FIG. 3B, brackets 314 may be used to couple
the stent 300 to the distal section 308 of the delivery guide.
Separation of the stent 306 from the brackets 314, e.g., by one of
the detachment processes mentioned above, releases the distal end
306 of the stent from a distal section 308 of the delivery guide,
allowing the stent distal end 306 to expand in the tubular
organ.
[0052] Controllable release of an end of an implant from the
delivery guide may be accomplished using the structure of FIG.
3C.sub.1. Brackets 314 couple the stent proximal end 310 to the
distal region 312 of the tubular member 313 that forms a portion of
the delivery guide. The brackets 314 have a ramped region 316 which
are proximally adjacent to an enlarged (and perhaps ball- or
barrel-shaped) portion 318 of the delivery guide and bracket arms
320. The delivery guide and stent each have a delivery diameter,
and these delivery diameters may be substantially equal prior to
release of the stent. When the actuator 305 is moved proximally, as
shown by the direction of the arrow, the ball-shaped portion 318
forces the ramped regions 316 of the brackets outward from the
delivery guide axis, in a radial fashion, causing the bracket arms
320 to be displaced radially outwardly from the proximal end 310 of
the stent, thereby releasing the stent proximal end 310.
[0053] FIG. 3C.sub.2 shows the results of moving the actuator 305
proximally. The clips (316) have rotated as shown due to the force
exerted upon the ramps (317) by the ball (318). The implant (320)
has expanded in diameter from that found in its undelivered
form.
[0054] The actuator may be attached, perhaps with a distal
radioopaque coil or directly, to a distal section (not shown) of
the guide member.
[0055] FIG. 3D.sub.1, shows a delivery system 319 in which the two
ends of the implant 321 may be independently deployed by using an
actuator 304 having a proximal releasing ball 322 and a distal
releasing ball 327. The implant 321 is located in a gap between
sections of the delivery guide and are releasably attached to the
delivery guide by brackets or clips. The two balls are spaced in
such a way that, in the variation shown in FIG. 3D.sub.1, the
distal ball 327 releases the distal end 331 of implant 321 and the
proximal ball 322 then releases the proximal end 329 of implant 321
upon additional proximal movement of actuator 304. This sequence of
events is shown in FIGS. 3D.sub.1, 3D.sub.2, and 3D.sub.3. The
implant 321, is shown to be completely released in FIG. 3D.sub.3.
In this variation, the implant 321 may be self-expanding, e.g.,
constructed of a superelastic alloy such as nitinol or another
alloy having high elasticity, e.g., an appropriate stainless
steel.
[0056] A structure similar to that shown in FIGS. 3D.sub.1,
3D.sub.2, and 3D.sub.3 may also be used to deploy an implant using
fluid pressure as the releasing impetus.
[0057] FIGS. 3E.sub.1, 3E.sub.2, 3E.sub.3 and 3E.sub.4 show a
hydraulic variation. Shown are the delivery guide 350, having a
hollow lumen 352, a self-expanding implant 354 (shown variously as
non-expanded (e.g., in a "first form") in FIG. 3E.sub.1, partially
expanded in FIG. 3E.sub.2, and fully expanded in FIGS. 3E.sub.3 and
3E.sub.4 (e.g., in a "second form")), and an actuator 356 with a
sealing member 358 and a radio-opaque member 360.
[0058] The implant 354 (here shown to be a stent or the like) is
held to the delivery guide 350 during delivery to the selected
treatment site using distal brackets 364 and proximal brackets 362
or clips or the like. The proximal and distal brackets (364, 362)
either include regions that cooperate with the fluid in lumen 352
to move upon application of increased pressure in that lumen 352
and release the implant 350 or move in concert with a separate
pressure sensitive motion component.
[0059] FIG. 3E.sub.1 shows the actuator 356 as the sealing member
358 approaches the various orifices or openings (proximal orifices
366 and distal orifices 368) communicating from the lumen 356 to
the hydraulically or fluidly actuatable clips or retaining brackets
(proximal brackets 362 and distal brackets 364).
[0060] Included in the description of this variation is a
radio-opaque marker 360 on the actuator shaft 356 that allows the
user to simply line up that actuator marker 360 with a
corresponding radio-opaque marker 370 or the delivery guide 350,
increase the pressure in lumen 352 (via syringe, pump, etc.) and
deploy the proximal end 371 of implant 354. The interior pressure
raises or rotates the proximal clips or brackets 362 and moves them
out of contact with the implant 354. FIG. 3E.sub.2 shows the
movement of the proximal end of implant 354 away from the delivery
guide 350.
[0061] FIG. 3E.sub.3 shows the axial movement of actuator 356
distally to a position where the sealing member 358 is positioned
to actuate distal clips or brackets 364 and release the distal end
of implant. Again, a radio-opaque marker 374 (perhaps with an
additional identification band 376) has been depicted to show
alignment of the radio-opaque marker or band 360 on the actuator
shaft 356 prior to the increase in pressure for deployment.
[0062] FIG. 3E.sub.4 shows final deployment at the implant 354 and
proximal movement at the actuator 356, just prior to withdrawal of
the delivery guide 350. The distal and proximal clips or brackets
(362, 364) have relaxed to the surface of the delivery guide
350.
[0063] Alternatives to certain of the elements shown in the
variation found in FIGS. 3E.sub.1 to 3E.sub.4 is seen in FIGS.
3F.sub.1 and 3F.sub.2 and includes, e.g., a cover element 380 to
block or cover proximal orifices 366 during the pressurization of
the distal orifices 368. The cover element 380 includes holes 382
to allow fluid flow past the cover element 380.
[0064] FIG. 3G, shows a variation of the described system in which
an implant or stent 371 is maintained in position on a hollow
delivery guide 373 using spring clips 375 proximally and 377
distally. The spring clips hold the implant 371 in place during
delivery and against guide member 373. An actuator 379 is used to
remove the clips 375, 377 sequentially and to release each end of
implant 371 in an independent fashion. Clips 375 and 377, after
actuation or release, remain interior to the guide member 373 for
later removal with that guide member. The system shown in FIGS.
3G.sub.1, 3G.sub.2 and 3G.sub.3 may be used to deliver a number of
implants in a sequential fashion. Since the retainer clips 375, 377
remain within the guide member 373 after delivery, the actuator 379
is able to slide past the site on guide member 373 where the clips
375, 377 resided prior to implant 371 deployment, down to and
distally to a site on the guide member having another implant for
subsequent delivery. Consequently, an arrangement such as this may
be used to deploy, in a sequential fashion, a number of stents or
the like without withdrawal of the guide member.
[0065] In the variation shown in FIGS. 3G.sub.1, 3G.sub.2 and
3G.sub.3, the clips 375 and 377 are spring-biased to collapse
within the lumen 381 of the guide member 373 once they are pushed
into the respective slots 383 provided for such retraction. Such
spring loaded clips retain the self expanding stent or implant 371
onto the face of guide member 373. Each of clips 375, 377 are shown
in this variation to have hook members 387, 389 that engage the
implant 371, often axially stretching the implant 371 and
maintaining the delivery radius of the implant 371 as shown.
[0066] As shown in FIG. 3G.sub.1, actuator 379 is pushed distally
along the outer surface of guide member 373 until it contacts the
proximal end of clip 375. Further distal movement of actuator 379
urges clip 375 into lumen 381 thereby rotating horn 387 out of
cooperating receptacle area in implant 371.
[0067] FIG. 3G.sub.2 shows the results of such movement after clip
375 has completed its springed closure within lumen 381. As shown
in that Figure, the proximal end of implant 371 has expanded and
yet the distal end of implant 371 remains closed and hooked to
distal clip 377. This semi-open condition allows for some
adjustment of the implant if needed. FIG. 3G.sub.3 shows the
results of additional distal movement of actuator 379 until it
contacts distal clip 377 (shown in FIG. 3G.sub.3 in its collapsed
form ) and thereby allowing the distal end of implant 371 to
self-expand into the chosen treatment site.
[0068] FIG. 3G.sub.3 shows that guide member 379 is free. Implant
371 is shown in its self expanded form no longer adjacent the
central guide member 379. Actuator 379 is situated within implant
371 and is no longer in contact with proximal clip 375 nor distal
clip 377. Actuator 379 is thus able to continue distally to another
implant containing site positioned in a more distal site on the
guide member 373.
[0069] The mechanical variation shown in FIGS. 3G.sub.1, 3G.sub.2,
3G.sub.3 may be modified in such a way that the actuator is
interior to the lumen of the guide member and deploys the implant
upon distal movement of the actuator by providing an actuator with
a slot or other "room-making" provisions in the actuator. The
actuator and any retained clips would then be used to actuate the
clips in the next more distal implant if so desired.
[0070] In yet a further variation, the system releases an implant
(shown as a stent 404 in FIG. 4) attached to a delivery guide 400
by one or more attachment arms 402 positioned, e.g., at the implant
proximal and distal ends, by sliding a tubular member 406, mounted
co-axially on the delivery guide 400, distally over the delivery
guide 400. The stent 404 is secured to the delivery guide 400 when
the attachment arms 402 are in a radially expanded configuration
(as illustrated in FIG. 4). The tubular member 406 urges the
attachment arms 402 into a compressed configuration as it slides
distally over the delivery guide 400, in the direction of the
arrow. When the attachment arms 402 are compressed by the tubular
member 406, they are moved inward from the stent 404, toward the
central axis of the delivery guide 400, thereby releasing the stent
404 from the delivery guide 400. Stent detachment occurs in a
serial fashion as the tubular member 406 is moved distally, with
detachment of the stent proximal end 408 occurring before
detachment at the stent distal end 410. Consequently, if the stent
position requires readjustment after detachment of the stent
proximal end, the stent may be repositioned prior to detaching the
stent distal end. In one variation, the tubular member is a balloon
catheter.
[0071] The attachment arms 402 are generally made from the same
materials as the delivery guide 400, e.g., stainless steel or
nickel-titanium alloy, and will typically have a length, thickness,
shape, and flexibility appropriate for its intended mechanism of
release. The distal ends 412 of the attachment arms may be of any
design, so long as one or more of them, when in a radially expanded
configuration, secures a portion of a stent to a delivery guide,
and when in a compressed configuration, releases that same stent
portion from the delivery guide.
[0072] The tubular member may be a thin-walled tube (e.g.,
approximately 0.005 cm (0.002 inches) in thickness) with an outside
diameter ranging from about 0.025 cm to about 0.139 cm (0.010
inches to about 0.055 inches), more usually from about 0.025 cm to
about 0.05 cm (0.010 inches to about 0.020 inches), and more
usually still from about 0.025 cm to about 0.035 cm (0.010 inches
to about 0.014 inches). Depending on such factors as degree of
flexibility or durometer required, they may be made from various
metals or metal alloys, including, but not limited to, stainless
steel and nickel-titanium alloy, or from various polymers, such as
polyvinyl chloride, polyethylene, polyethylene terephthalate, and
polyurethane.
[0073] FIGS. 5A, 5B, and 5C show a variation of the described
delivery system 500 in which a member of electrolytic delivery
joints are used to deploy an implant 502, such as a stent.
[0074] The electrolytic delivery joints shown here (e.g., 504 in
FIG. 5C) are well known as controllable delivery joints for
placement of vaso-occlusive coils. One such commercially available
device using an electrolytically detachable joint is sold by Target
Therapeutics, a subsidiary of Boston Scientific Corp., as the
Guglielmi Detachable Coil (or "GDC"). Numerous patents to Dr.
Guglielmi describe the theory of its use.
[0075] In essence, the electrolytically erodible joint is a section
of an electrical circuit that is not insulated and is of a metallic
material that does not form insulating oxides when exposed to an
aqueous environment (e.g., aluminum and tantalum) and is
sufficiently "non-noble" that is will either electrolytically erode
by ionic dissolution into an anatomical fluid or, perhaps,
electrochemically erode by forming readily soluble oxides or
salts.
[0076] The erodible joint 504 shown in FIG. 5C is a bare metal of a
size, diameter, etc. that erodes away when a current is applied to
insulated wire 506. The current flow is from a power supply through
insulated wire 506, bare joint 504, into the ionic anatomical fluid
surrounding the site to be treated, and back to a return electrode
situated perhaps on the patient's skin and then back to the power
supply. The current flows through the circuit so long as the joint
504 exists.
[0077] With that background, FIG. 5A shows a device having several
joints (504, 508, 510, 512) that each may be independently severed
to controllably deploy the implant 502. Implant 502 is shown having
coils (514, 516) that are terminated at each end by an erodible
joint and that, prior to the severing of a joint, hold this implant
502 to the surface of the delivery member 520. The implant 500 is
self-expanding, once released. The wires forming the two coils in
this variation slide within the implant or "uncoil" and thereby
allow the implant body itself to expand. The coils may comprise (if
electrically connected to the erodible joint) a metal that is
higher in the Mendelev Electromotive Series than is the composition
at the electrolytic joint or the coils may comprise a polymer that
may be bio-erodible or not.
[0078] In any case, a suitable way to assure that the coils (514,
516) maintain the low profile of the implant 502 during delivery is
via the placement of the various conductive wires (506, 516, 518,
520) through the adjacent holes (524, 526, 528) and fill the holes
with e.g., an epoxy to hold all in place. Independently causing
current to flow through each of the joints will release the implant
in the region of the released joint Once all joints are eroded, the
implant is released.
[0079] Although release from proximal and distal ends of the
tubular form of the implants has been described, detachment from a
delivery guide is not so limited. In another variation, the stent
is attached to the delivery guide at one or more positions along
the length of the stent, in addition to attachment at the proximal
and distal implant ends. Once the distal stent end is released, the
additional attachments may be independently released until
detachment at the proximal implant end releases the implant
entirely from the delivery guide. Serial release may provide better
control of positioning in tubular organs.
[0080] FIGS. 5D and 5E show in more detail, the components of an
electrolytic joint (as may be found in FIGS. 5A, 5B and 5C) and
another electrically actuated joint using a meltable or softenable
or polymerically sizable joint
[0081] FIG. 5D shows the insulated wire 524 with insulation 523 and
conductor 525. The electrolytic joint 504 is also shown. In this
variation, the wire 524 is shown to be secured into the delivery
guide wall 520 by, e.g., an epoxy 527, an alternative or
cooperative band or component 529 holding the wire 524 to the
surface of guide member 520 is also shown. After erodable joint 504
is eroded, the implant of 502 expands and leaves the securement
band 529 on the delivery guide 520.
[0082] FIG. 5E shows a similar variation but the joint comprises a
thermoplastic adhesive or shape changing polymer 531 situated on
the end of wire 525 and within a cup or other receptacle 533. The
adhesive is of the type that changes form or viscosity upon
application of current to the joint. In this variation, the
thermoplastic is rendered conductive, but resistive, by
introduction of material such as carbon black into the polymeric
adhesive. As soon as the polymer changes its shape, form, or phase,
the implant expands to the desired form about the central guide
member 520 again, the wire may be held in place with an adhesive
527 if so desired.
[0083] Although the figures show wires and other remnants of the
joints remaining exterior to the central guide member 520 and the
others shown and described here, it is desirable that these not be
situated in such a way that they will harm the tissues into which
they are placed.
Delivery Method
[0084] The implant delivery devices described herewith may include
multiple implants on a single delivery guide or may be used in
conjunction with other instruments, as seen appropriate, to treat
the target site. In general, the tubular organ of interest is
percutaneously accessed, but the method of accessing will usually
be dependent on the anatomy of the organ, medical condition being
treated, health status of the subject, and the like. Consequently,
access by a laparoscopic or open procedure may also be
obtained.
[0085] FIGS. 6A-6D show the general method of deploying a stent
using my described system. After obtaining access to the tubular
organ of interest 600 (blood vessel in FIG. 6A), a delivery guide
602 is placed through the selected area of stenosis 604 at the
target site. A balloon catheter 606 is then advanced over the
delivery guide 602, and balloon angioplasty performed to dilate the
area of stenosis 604 (FIG. 6B). The balloon catheter 606 is then
retracted proximally and the delivery guide 602 exchanged for a
stent delivery device 608 (FIG. 6C). Appropriate placement of the
stent is guided by radioopaque markers 616 on the delivery guide
612. The distal end 610 of the stent is then released from the
delivery guide 612. At this point, stent position may again be
checked by verifying the location of the radioopaque markers. The
proximal stent end 614 is then released from the delivery guide
612.
[0086] If desired, an embolic filter may be used during stent
deployment to filter any debris generated during the procedure. The
filter will usually be attached to the delivery guide such that it
filters debris distal to the stent, but may also be attached to the
delivery guide proximal to the stent, or both distal and proximal
to the stent. The filter may be of any design, as long as it does
not affect the substantially atraumatic, low profile, and
controlled release characteristics of the stent delivery device.
Typically, the filter is basket-shaped, and made from a
shape-memory material, e.g., an alloy of titanium and nickel. The
filter will usually be contained within the balloon catheter lumen,
and deployed to its pre-designed shape once the balloon catheter is
removed. Following placement of the stent, the balloon catheter may
be advanced over the delivery guide to enclose the filter with any
accumulated debris. The balloon catheter, filter, and delivery
guide may then be removed from the body.
Applications
[0087] The implant delivery system may be used in mammalian
subjects, preferably humans. Mammals include, but are not limited
to, primates, farm animals, sport animals, cats, dogs, rabbits,
mice, and rats.
[0088] The system may be employed for implant delivery into lumens
of tubular organs including, but not limited to, blood vessels
(including intracranial vessels, large vessels, peripheral vessels,
aneurysms, arteriovenous malformations, arteriovenous fistulas),
ureters, bile ducts, fallopian tubes, cardiac chambers, ducts such
as bile ducts and mammary ducts, large and small airways, and
hollow organs, e.g., stomach, intestines, and bladder. The system
may also be employed for implant delivery into solid organs or
tissues including, but not limited to, skin, muscle, fat, brain,
liver, kidneys, spleen, and benign and malignant tumors.
Preferably, the implant is delivered to a target site in a blood
vessel lumen.
[0089] Clinically, the system may generally be used to treat
stenosis of various tubular organs, arising from such etiologies as
atherosclerosis, autoimmune conditions, scarring, or exterior
compression, e.g., as may be seen with a neoplastic process. The
system may also be used to treat medical conditions in which
luminal occlusion is desired, e.g., to treat aneurysms,
arteriovenous fistulas, and arteriovenous malformations.
Furthermore, the system may be employed to deliver implants into
such areas as joint spaces, spinal discs, and the intraperitoneal
or extraperitoneal spaces.
[0090] All publications, patents, and patent applications cited
herein are hereby incorporated by reference in their entirety for
all purposes to the same extent as if each individual publication,
patent, or patent application were specifically and individually
indicated to be so incorporated by reference. Although the
foregoing invention has been described in some detail by way of
illustration and example for purposes of clarity of understanding,
it will be readily apparent to those of ordinary skill in the art
in light of the teachings of this invention that certain changes
and modifications may be made thereto without departing from the
spirit and scope of the appended claims.
* * * * *