U.S. patent application number 14/904647 was filed with the patent office on 2016-05-26 for methods and apparatus for treating pulmonary embolism.
The applicant listed for this patent is INCEPTUS MEDICAL, LLC. Invention is credited to Brian J. Cox, Paul Lubock, Richard Quick, Robert Rosenbluth.
Application Number | 20160143721 14/904647 |
Document ID | / |
Family ID | 52277699 |
Filed Date | 2016-05-26 |
United States Patent
Application |
20160143721 |
Kind Code |
A1 |
Rosenbluth; Robert ; et
al. |
May 26, 2016 |
METHODS AND APPARATUS FOR TREATING PULMONARY EMBOLISM
Abstract
A device and method for intravascular treatment of an embolism
is disclosed herein. One aspect of the present technology, for
example, is directed toward a clot treatment device that includes a
support member configured to extend through a delivery catheter and
a plurality of clot engagement members positioned about the
circumference of a distal portion of the support member. The clot
engagement members can be configured to penetrate clot material
along an arcuate path and mechanically macerate clot and release
embolic particles when re-sheathed into the delivery catheter.
Inventors: |
Rosenbluth; Robert; (Laguna
Niguel, CA) ; Lubock; Paul; (Monarch Beach, CA)
; Cox; Brian J.; (Laguna Niguel, CA) ; Quick;
Richard; (Mission Viejo, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
INCEPTUS MEDICAL, LLC |
Aliso Viejo |
CA |
US |
|
|
Family ID: |
52277699 |
Appl. No.: |
14/904647 |
Filed: |
July 14, 2014 |
PCT Filed: |
July 14, 2014 |
PCT NO: |
PCT/US2014/046567 |
371 Date: |
January 12, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14299933 |
Jun 9, 2014 |
9259237 |
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|
14904647 |
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|
61845796 |
Jul 12, 2013 |
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61864356 |
Aug 9, 2013 |
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61949953 |
Mar 7, 2014 |
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Current U.S.
Class: |
600/200 |
Current CPC
Class: |
A61B 2017/320008
20130101; A61F 2002/016 20130101; A61F 2/011 20200501; A61F 2/01
20130101; A61B 2017/00778 20130101; A61B 17/320725 20130101; A61B
17/221 20130101; A61B 2017/22034 20130101 |
International
Class: |
A61F 2/01 20060101
A61F002/01 |
Claims
1. A clot treatment device for treating a pulmonary embolism within
a blood vessel, the clot treatment device being moveable between a
low-profile undeployed state and a deployed state, the clot
treatment device comprising: a support member configured to extend
through a delivery catheter, wherein the support member has a
proximal portion and a distal portion; a plurality of clot
engagement members positioned circumferentially about at least an
area of the distal portion of the support member, wherein
individual clot engagement members have a curved portion; wherein
the clot engagement members are configured to penetrate clot
material along an arcuate path and mechanically macerate clot
material and release embolic particles when re-sheathed into the
delivery catheter.
2. The clot treatment device of claim 1 wherein, in the deployed
state, individual curved portions of the clot engagement members
project radially outwardly relative to the support member in a
curve that has a proximally extending section which defines a
proximally facing concave portion, and wherein the individual
curved portions further include an end section that curves radially
inwardly from the proximally extending section.
3. A method of treating a pulmonary embolism, comprising: accessing
a venous vessel of a patient; inserting a catheter in the vessel
and urging the catheter through the vessel, through chambers of the
patient's heart and into a pulmonary artery until a distal end of
the catheter is located at a region distal of a pulmonary embolism;
delivering a treatment device having a plurality of radially
extending members through the catheter; disturbing the embolus by
mechanical maceration of the embolus to release embolic particles
without capturing the embolic particles in an embolic protection
device; and establishing one or more blood flow channels through
the embolus wherein the one or more blood flow channels facilitate
natural lysis of the embolus.
4. A method of treating a pulmonary embolism comprising: delivering
an embolectomy device through the heart to a pulmonary embolism
that at least partially restricts blood flow through a pulmonary
vessel, wherein the embolectomy device comprises an expandable
cylindrical section and a radial expansion member configured to
expand outwardly from the cylindrical section; deploying the
embolectomy device within the pulmonary embolism so as to restore
blood flow through said pulmonary embolism, wherein deploying the
embolectomy device comprises expanding the cylindrical section
within the pulmonary embolism such that the cylindrical section
forms an expanded flow channel through the pulmonary embolism and
expanding the radial expansion member to a greater extent than the
cylindrical section, and wherein at full expansion of the
cylindrical member the radial expansion member projects outward
from the cylindrical member; fragmenting the pulmonary embolism
while moving the embolectomy device and at least a portion of the
pulmonary embolism along the pulmonary vessel; and withdrawing the
embolectomy device and at least a portion of the pulmonary embolism
from the pulmonary vessel.
5. A device for treating a pulmonary embolism that at least
partially restricts blood flow through a pulmonary vessel, the
device comprising: an elongated shaft having a proximal region and
a distal region; an expandable braid attached to the distal region
of the elongated shaft, the braid having a plurality of radially
extending portions and at least one cylindrical portion, and the
radially extending portions and the cylindrical portion being
configured to move from a compressed state sized to fit in a
delivery catheter to an expanded state; wherein the cylindrical
portion is between a pair of the radially extending portions, and
in the expanded state the cylindrical portion is configured to
press radially outward against the pulmonary embolism; wherein the
radially extending portions extend radially outward from the
cylindrical portion in the expanded state such that portions of the
pulmonary embolism are retained between the radially extending
portions; and wherein the cylindrical portion has a first length
along a longitudinal direction of the braid in the expanded state
and the radially extending portions have a second length along the
longitudinal direction of the braid in the expanded state that is
less that the first length; and wherein the radially extending
portions and/or the cylindrical portions are configured to elongate
and/or contract when re-sheathed into the delivery catheter to
mechanically macerate clot and release embolic particles.
6. The device of claim 1 wherein at least a portion of the
individual radially extending portions is disk-shaped.
7. The device of claim 1 wherein the individual radially extending
portions include a curved portion and a linear portion.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims the benefit of U.S.
Provisional Patent Application No. 61/845,796, filed Jul. 12, 2013,
entitled "DEVICES AND METHODS FOR TREATING OF VASCULAR OCCLUSION",
U.S. Provisional Patent Application No. 61/864,356, filed Aug. 9,
2013, entitled "DEVICES AND METHODS FOR TREATING OF VASCULAR
OCCLUSION", U.S. Provisional Patent Application No. 61/949,953
filed Mar. 7, 2014, entitled "METHODS AND APPARATUS FOR TREATING
EMBOLISM," and U.S. patent application Ser. No. 14/299,933, filed
Jun. 9, 2014, entitled "METHODS AND APPARATUS FOR TREATING
PULMONARY EMBOLISM", all of which are incorporated herein by
reference in their entireties.
TECHNICAL FIELD
[0002] The present technology relates generally to devices and
methods for intravascular treatment of emboli within a blood vessel
of a human patient. Many embodiments of the technology relate to
the intravascular treatment of a pulmonary embolism.
BACKGROUND
[0003] Thromboembolism occurs when a thrombus or blood clot trapped
within a blood vessel breaks loose and travels through the blood
stream to another location in the circulatory system, resulting in
a clot or obstruction at the new location. As shown schematically
in FIG. 1, when a clot C forms in the venous circulation V, it
often travels to the lungs L via the heart H and lodges within a
pulmonary blood vessel PV causing a pulmonary embolism PE. A
pulmonary embolism PE can decrease blood flow through the lungs L,
which in turn causes decreased oxygenation of the lungs L, heart H
and rest of the body. Moreover, pulmonary embolisms can cause the
right ventricle RV of the heart H to pump harder to provide
sufficient blood to the pulmonary blood vessels PV, which can cause
right ventricle RV dysfunction (dilation), and heart failure in
more extreme cases.
[0004] Conventional approaches to treating thromboembolism and/or
pulmonary embolism include clot reduction and/or removal. For
example, anticoagulants can be introduced to the affected vessel to
prevent additional clots from forming, and thrombolytics can be
introduced to the vessel to at least partially disintegrate the
clot. However, such agents typically take a prolonged period of
time (e.g., hours, days, etc.) before the treatment is effective
and in some instances can cause hemorrhaging. Transcatheter clot
removal devices also exist, however, such devices are typically
highly complex, prone to cause trauma to the vessel, hard to
navigate to the pulmonary embolism site, and/or expensive to
manufacture. Conventional approaches also include surgical
techniques that involve opening the chest cavity and dissecting the
pulmonary vessel. Such surgical procedures, however, come with
increased cost, procedure time, risk of infection, higher
morbidity, higher mortality, and recovery time. Accordingly, there
is a need for devices and methods that address one or more of these
deficiencies.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] Many aspects of the present technology can be better
understood with reference to the following drawings. The components
in the drawings are not necessarily to scale. Instead, emphasis is
placed on illustrating clearly the principles of the present
disclosure.
[0006] FIG. 1 is a schematic illustration of an embolism traveling
through the heart and forming an embolism in a pulmonary
vessel.
[0007] FIG. 2A is a perspective view of one embodiment of a clot
treatment device in a collapsed or delivery state configured in
accordance with an embodiment of the present technology.
[0008] FIG. 2B is a perspective view of the clot treatment device
of FIG. 2A in a deployed state configured in accordance with an
embodiment of the present technology.
[0009] FIG. 2C is an enlarged view of a portion the clot treatment
device shown in FIG. 2A.
[0010] FIG. 2D is an axial-perspective view of a portion of the
clot treatment device shown in FIG. 2A.
[0011] FIGS. 3A-3C are isolated, enlarged side views of clot
engagement members in a deployed state configured in accordance
with embodiments of the present technology.
[0012] FIG. 4A is a perspective view of another embodiment of a
clot treatment device in a collapsed or delivery state configured
in accordance with an embodiment of the present technology.
[0013] FIG. 4B is a perspective view of the clot treatment device
of FIG. 4A in a deployed state configured in accordance with an
embodiment of the present technology.
[0014] FIG. 5 is a perspective view of a clot treatment device
configured in accordance with another embodiment of the present
technology.
[0015] FIG. 6 is a perspective view of a clot treatment device
configured in accordance with another embodiment of the present
technology.
[0016] FIG. 7A is a perspective view of a clot treatment device
configured in accordance with another embodiment of the present
technology.
[0017] FIG. 7B is a cross-sectional end view taken along line 7B-7B
in FIG. 7A.
[0018] FIG. 8 is a perspective view of a clot treatment device
configured in accordance with another embodiment of the present
technology.
[0019] FIG. 9A is a perspective view of a clot treatment device
configured in accordance with another embodiment of the present
technology.
[0020] FIG. 9B is a cross-sectional end view of a portion of the
clot treatment device shown in FIG. 9A.
[0021] FIG. 9C is a side view of a binding member configured in
accordance with the present technology.
[0022] FIG. 10 is a side partial cross-sectional view of a delivery
system configured in accordance an embodiment of the present
technology.
[0023] FIGS. 11A-11K illustrate a method for using a clot treatment
device configured in accordance with the present technology to
remove clot material from a vessel.
[0024] FIG. 12 is a cross-sectional view of a preferred embodiment
of a clot treatment device in accordance with the present invention
in a compressed, undeployed state;
[0025] FIG. 13 is a top view of a preferred embodiment of a clot
treatment device in accordance with the present invention;
[0026] FIGS. 14A-14F are a series of cross-sectional views of a
preferred embodiment of the method and device of the present
invention;
[0027] FIGS. 15A-15B are a series of cross-sectional views of a
preferred embodiment of the method and device of the present
invention;
[0028] FIG. 16 is a cross-sectional view of another preferred
embodiment of the method and device of the present invention;
and,
[0029] FIGS. 17A-17H show cross-sectional views of preferred
embodiments of a clot treatment device in accordance with the
present invention.
[0030] FIG. 18 is a cross-sectional view of a clot treatment device
in accordance with another embodiment of the present
technology.
[0031] FIGS. 19 and 20 are detailed cross-sectional views of a
distal portion and a proximal portion, respectively, of an
expandable member of a clot treatment device in accordance with an
embodiment of the present technology.
[0032] FIGS. 21 and 22 are detailed cross-sectional views of a
proximal portion and a distal portion, respectively, of an
expandable member of a clot treatment device in accordance with
another embodiment of the technology.
[0033] FIGS. 23-26 are side views of guide members for use with
clot treatment devices and methods in accordance with embodiments
of the present technology.
DETAILED DESCRIPTION
[0034] Specific details of several embodiments of clot treatment
devices, systems and associated methods in accordance with the
present technology are described below with reference to FIGS.
2A-26. Although many of the embodiments are described below with
respect to devices, systems, and methods for treating a pulmonary
embolism, other applications and other embodiments in addition to
those described herein are within the scope of the technology.
Additionally, several other embodiments of the technology can have
different states, components, or procedures than those described
herein. Moreover, it will be appreciated that specific elements,
substructures, advantages, uses, and/or other features of the
embodiments described with reference to FIGS. 2A-26 can be suitably
interchanged, substituted or otherwise configured with one another
in accordance with additional embodiments of the present
technology. Furthermore, suitable elements of the embodiments
described with reference to FIGS. 2A-26 can be used as standalone
and/or self-contained devices. A person of ordinary skill in the
art, therefore, will accordingly understand that the technology can
have other embodiments with additional elements, or the technology
can have other embodiments without several of the features shown
and described below with reference to FIGS. 2A-26.
[0035] With regard to the terms "distal" and "proximal" within this
description, unless otherwise specified, the terms can reference a
relative position of the portions of a clot treatment device and/or
an associated delivery device with reference to an operator and/or
a location in the vasculature.
I. Selected Embodiments of Clot Treatment Devices
[0036] FIG. 2A is a perspective view of one embodiment of a clot
treatment device 200 ("the device 200") in a low-profile or
delivery state, and FIG. 2B is a perspective view of the device 200
in an unrestricted expanded or deployed state that is well suited
for removing clot material from a blood vessel (e.g., a pulmonary
blood vessel). Referring to FIGS. 2A and 2B together, the device
200 can include a support member 204 and a plurality of clot
engagement members 202 positioned about the circumference of the
support member 204. As best shown in FIG. 2B, the individual clot
engagement members 202 can include a first portion 206 having a
proximal region 205 and a distal region 207, and a second portion
208 extending from the distal region 207 of the first portion 206.
In the delivery state, as shown in FIG. 2A, the clot engagement
members 202 can be generally linear and extend generally parallel
to the support member 204. In the expanded state, as shown in FIG.
2B, the second portions 208 can project radially outwardly relative
to the support member 204 in a curved shape. The second portions
208 can have a proximally facing section 212 which defines a
proximally facing concave portion, and, in some embodiments, the
second portions 208 can further include an end section 214 that
curves radially inwardly from the proximally facing section 212.
When deployed within a blood vessel adjacent to clot material, the
clot engagement members 202 are configured to penetrate the clot
material along an arcuate path and hold clot material to the device
200, as discussed in greater detail below with reference to FIGS.
10-11K.
[0037] FIG. 2C is an enlarged view of a portion of the device 200
of FIG. 2A showing that the device 200 can include a hub 210 that
couples the proximal regions 205 of the first portions 206 to the
support member 204. The first portions 206 can extend distally from
their proximal regions 205 in a longitudinal direction along the
length of the support member 204 to their distal regions 207, and
the distal regions 207 can be free to move relative to the support
member 204. As such, the first portions 206 can be cantilevered
portions of the clot engagement members 202 that enable the clot
engagement members 202 to flex and move independently of the
support member 204 in response to forces present within the blood
vessel, such as blood flow, gravity, and/or the local anatomy. The
first portions 206 can be sufficiently rigid to maintain a
generally linear shape along their respective lengths, yet flexible
enough to bend and/or flex about the hub 210. For example, in some
instances, in response to local forces, one or more of the distal
regions 207 of the first portions 206 can be spaced radially apart
from the support member 204 such that one or more first portions
206 forms an angle with the support member 204.
[0038] Referring back to FIGS. 2A and 2B, the first portions 206 of
different clot engagement members 202 can have different lengths
such that the second portions 208 of at least two clot engagement
members extend radially outwardly at different locations along the
length of the support member 204. For example, as best shown in
FIG. 2B, the clot treatment device 200 can include a first group
202a of clot engagement members 202 having first portions 206 with
a first length L1, a second group 202b of clot engagement members
202 having first portions 206 with a second length L2 greater than
the first length L1, a third group of clot engagement members 202c
having first portions 206 with a third length L3 greater than the
second length L2, a fourth group of clot engagement members 202d
having first portions 206 with a fourth length L4 greater than the
third length L3, a fifth group of clot engagement members 202e
having first portions 206 with a fifth length L5 greater than the
fourth length L4, and a sixth group of clot engagement members 202f
having first portions 206 with a sixth length L6 greater than the
fifth length L5. It will be appreciated that although six groups of
clot engagement members are shown in FIGS. 2A and 2B, in other
embodiments the clot treatment device can have more or fewer than
six groups (e.g., one group, two groups, three groups, seven
groups, ten groups, etc.) and/or the lengths of all or some of the
first portions 206 can be the same or different.
[0039] Moreover, the second portions 208 of the first group 202a of
clot engagement members 202 extend radially outward at a first area
of the support member 204, the second portions 208 of the second
group 202b of the clot engagement members 202 extend radially
outward from a second area of the support member 204, the second
portions 208 of the third group 202c of clot engagement members 202
extend radially outward from a third area of the support member
204, the second portions 208 of the fourth group 202d of clot
engagement members 202 extend radially outward from a fourth area
of the support member 204, the second portions 208 of the fifth
group 202e of clot engagement members 202 extend radially outward
from a fifth area of the support member 204, and the second
portions 208 of the sixth group 202f of clot engagement members 202
extend radially outward from a sixth area of the support member
204. It will be appreciated that although six areas of clot
engagement members are shown in FIGS. 2A and 2B, in other
embodiments the clot treatment device can have more or fewer than
six areas (e.g., one area, two areas, three areas, five areas, nine
areas, etc.).
[0040] FIG. 2D is an enlarged, axial-perspective view of a portion
of the device 200 in which the groups of clot engagement members
202a-f (only the first, second and third groups 202a-c shown) are
arranged about the circumference of the support member 204 such
that the second portions (labeled 208a-c) of adjacent groups 202a-c
are circumferentially offset from one another. As such, in the
embodiment shown in FIG. 2D, the second portions 208 of adjacent
groups of clot engagement members 202a-f are not circumferentially
aligned, and thus can engage the clot material at different
circumferential positions along the length of the clot
material.
[0041] FIG. 3A is a side view of a clot engagement member 202 in
the expanded state. Individual clot engagement members can be made
from a shape memory material such that, when unconstrained, assume
a preformed curved shape. As shown in FIG. 3A, the second portion
208 can have an arcuate shape that includes an outwardly extending
section 216, the proximally facing section 212 extending from the
outwardly extending section 216, and the end section 214 extending
from the proximally facing section 212. In one embodiment, the
demarcation between the proximally facing section 212 and the end
section 214 occurs at an apex 218 of the second portion 208. The
proximally facing section 212 is configured to retain clot material
with the clot engagement member 202 as the device 200 is pulled
proximally through the vessel (arrow P), and the apex 218 provides
a smooth curve that can atraumatically slide along the vessel wall
as the device 200 is pulled proximally through the vessel. In the
embodiment shown in FIG. 3A, the second portion 208 of the clot
treatment device 200 can have a single or constant radius of
curvature R.sub.1. In other embodiments, such as the clot
engagement member 402 shown in FIG. 3B, the second portions 208 can
have a plurality of radii of curvature, such as a first region with
a first radius of curvature R.sub.1 and a second region with a
second radius of curvature R.sub.2. In the embodiment shown in
FIGS. 2A-2D, the second portions 208 of the clot engagement members
202 have a single radius of curvature that is the same for all of
the clot engagement members 202. In other embodiments, the device
200 can have a first group of second portions with a constant
radius of curvature and a second group of second portions with a
plurality of radii of curvature. Moreover, in additional
embodiments the device 200 can include a first group of second
portions having a first radius of curvature and a second group of
second portions having a second radius of curvature different than
the first radius of curvature. In some embodiments, the radius
R.sub.1 of the clot engagement members 202 can be between about 1.5
mm and about 12 mm, and in some embodiments, between about 2 mm and
about 12 mm.
[0042] As shown in FIG. 3C, the arc length a of the clot engagement
members 202 may be substantially greater than 180 degrees to
provide several benefits in performance of clot engagement and
retrieval. In particular, a greater arc length a can provide
improved clot engagement during retraction when resistance due to
clot friction and interference with the vessel wall deflects the
clot engagement member 202 distally (arrow D). A greater arc length
a may provide more deflection and/or unravelling or straightening
of the arcuate shape without loss of engagement with the clot. In
some embodiments, the arc length a of the clot engagement members
202 can be greater than about 200 degrees. In some embodiments the
arc length a of the clot engagement members 202 may be between
about 200 degrees and 340 degrees and between about 240 degrees and
300 degrees in other embodiments. It can be advantageous to keep
the arc length a under about 360 degrees so as to avoid overlap of
the clot engagement member 202. Greater arc length a can allow for
the use of smaller clot engagement member filaments or wires that
may be particularly beneficial for minimization of the collapsed
profile of the device. Greater arc length a can also allow for a
larger total number of clot engagement members 202 that also
enhance the ability of the device to remove embolic material from a
vessel. Moreover, in some embodiments, the distal end of the clot
engagement members 202 may define an angle with respect to the axis
of the support member and/or the straight portion of the engagement
members (as shown in FIG. 3C). This angle may be between about 30
degrees and about 90 degrees, and in some embodiments between about
40 degrees and about 80 degrees.
[0043] The clot engagement members 202 can be made from a variety
of materials. In a particular embodiment, the clot engagement
members 202 comprise a material with sufficient elasticity to allow
for repeated collapse into an appropriately sized catheter and full
deployment in a blood vessel. Such suitable metals can include
nickel-titanium alloys (e.g., Nitinol), platinum, cobalt-chrome
alloys, Elgiloy, stainless steel, tungsten, titanium and/or others.
Polymers and metal/polymer composites can also be utilized in the
construction of the clot engagement members. Polymer materials can
include Dacron, polyester, polyethylene, polypropylene, nylon,
Teflon, PTFE, ePTFE, TFE, PET, TPE, PLA silicone, polyurethane,
polyethylene, ABS, polycarbonate, styrene, polyimide, PEBAX,
Hytrel, polyvinyl chloride, HDPE, LDPE, PEEK, rubber, latex and the
like. In some embodiments, the clot engagement members 202 may
comprise an environmentally responsive material, also known as a
smart material. Smart materials are designed materials that have
one or more properties that can be significantly changed in a
controlled fashion by external stimuli, such as stress,
temperature, moisture, pH, electric or magnetic fields.
[0044] In some embodiments, portions of the exterior surfaces of
the support member 204 and/or clot engagement members 202 may be
textured, or the exterior surfaces can include microfeatures
configured to facilitate engagement or adhesion of thrombus
material (e.g., ridges, bumps, protrusions, grooves, cut-outs,
recesses, serrations, etc.). In some embodiments, the clot
engagement members 202 may be coated with one or more materials to
promote platelet activation or adhesion of thrombus material.
Adhesion of thrombi to clot engagement members 202 may facilitate
capture and/or removal.
[0045] In some embodiments, the clot treatment device 200 can
include between about 8 and about 80 clot engagement members 202,
and in some embodiments, between about 12 and about 60 clot
engagement members 202. In a particular embodiment, the clot
treatment device 200 can include between about 16 and about 40 clot
engagement members 202. The clot engagement members 202 can
individually have one consistent diameter or have a variety of
diameters (among the members 202) along their lengths. In addition,
an individual clot engagement member 202 may have a tapered or
varying diameter along its length to provide desired mechanical
characteristics. The average diameter of the clot engagement
members 202 can be between about 0.1 mm to about 0.2 mm in some
embodiments and in a particular embodiment, between about 0.12 mm
and 0.16 mm.
[0046] In any of the embodiments described herein, the clot
engagement members 202 can be formed from a filament or wire having
a circular cross-section. Additionally, the clot engagement members
202 can be formed from a filament or wire having a non-circular
cross-section. For example, filaments or wires having square,
rectangular and oval cross-sections may be used. In some
embodiments, a rectangular wire (also known as a "flat wire") may
have a height or radial dimension of between about 0.05 mm to about
0.2 mm. In some embodiments, a rectangular wire may have a width or
transverse dimension of between about 0.08 mm to about 0.3 mm. In
some embodiments, a rectangular wire may have a height to width
ratio of between about 0.3 to about 0.9 and between about 1 and
about 1.8.
[0047] FIGS. 4A and 4B illustrate an embodiment in which clot
engagement members having non-circular cross-sections are
fabricated from a tube (e.g., a hypotube). The tube may be cut or
machined by various means known in the art including conventional
machining, laser cutting, electrical discharge machining (EDM) or
photochemical machining (PCM). Referring to FIG. 4A, a tube may be
cut to form a plurality of clot engagement members 454 that are
integral with a hub member 456. The cut tube may then be formed by
heat treatment to move from a delivery state shown in FIG. 4A to a
deployed state shown in FIG. 4B in which an array of arcuate clot
engagement members 454 project radially outward. As is known in the
art of heat setting, a fixture or mold may be used to hold the
structure in its desired final configuration and subjected to an
appropriate heat treatment such that the clot engagement members
assume or are otherwise shape-set to the desire arcuate shape. In
some embodiments, the device or component may be held by a fixture
and heated to about 475-525.degree. C. for about 5-15 minutes to
shape-set the structure. In some embodiments, the tubular clot
engagement structure may be formed from various metals or alloys
such as Nitinol, platinum, cobalt-chrome alloys, 35N LT, Elgiloy,
stainless steel, tungsten or titanium.
[0048] FIG. 5 is a perspective view of another embodiment of a clot
treatment device 500 in a deployed state in accordance with the
present technology. As shown in FIG. 5, the clot treatment device
500 can include a plurality of clot engagement members 502
generally similar to the clot engagement members 202 and 402
described with reference to FIGS. 2A-4B, except the clot engagement
members 502 of FIG. 5 are arranged about the support member 204
such that the length of the first portions 506 increase in a
clockwise or counterclockwise direction about 360 degrees of the
support member 204. As such, the second portions 508 spiral around
the length of the support member 204 and each successive second
portion 508 extends from a location along the shaft that is
circumferentially offset and distal to the location of the
immediately adjacent second portion 508.
[0049] FIG. 6 is a perspective view of another embodiment of a clot
treatment device 600 in a deployed state in accordance with the
present technology. The clot treatment device 600 can include a
plurality of clot engagement members 602 generally similar to the
clot engagement members 202 and 402 described with reference to
FIGS. 2A-4B, except the second portions 608 of the clot engagement
members 602 of FIG. 6 are not arranged in groups, but instead
extend at irregular intervals from support member 204.
[0050] FIG. 7A is a perspective view of another embodiment of a
clot treatment device 700 in a deployed state in accordance with
the present technology, and FIG. 7B is a cross-sectional end view
taken along line 7B-7B in FIG. 7A. Referring to FIGS. 7A and 7B
together, the clot treatment device 700 can have groups of clot
engagement members 702a-f spaced along the support member 204. The
groups 702a-f can include a plurality of arcuate clot engagement
members 702 generally similar to the clot engagement members 202
and 402 described with reference to FIGS. 2A-4B, except the second
portions 708 of the clot engagement members 702 of FIG. 7A extend
at an angle from the support member 204 such that the distal ends
713 of the second portions 708 are not circumferentially aligned
with the corresponding proximal ends 711 of the second portions
708. For example, as shown in FIG. 7B, the second portions 708 can
extend at an angle .theta. from the first portions 706. In some
embodiments, the angle .theta. can be between about 10 and about 80
degrees. In a particular embodiment, the angle .theta. can be
between about 40 and about 60 degrees. Additionally, as shown in
FIGS. 4B and 7B, the clot engagement members may form a
substantially circular axial array about the axis of the support
member. A circular array may engage clot more uniformly and
securely than a non-circular array and thus may facilitate
retrieval and removal of clot from the vessel.
[0051] FIG. 8 is a perspective view of another embodiment of a clot
treatment device 800 in a deployed state in accordance with the
present technology. As shown in FIG. 8, the clot treatment device
800 can have groups of clot engagement members 802a-f spaced along
the support member 204. The groups 802a-f can include a plurality
of arcuate clot engagement members 802 generally similar to the
clot engagement members 202 and 402 described with reference to
FIGS. 2A-4B, except the clot engagement members 802 of FIG. 8 do
not include a first or cantilevered portion. As such, the clot
engagement members 802 include only a curved second portion 808
which is coupled to the support member 204 at one end (e.g., via
hubs 810a-f). In a particular embodiment, the clot engagement
members 802 can have a first portion; however, in such embodiments,
the first portions of the clot engagement members 802 are
relatively short (e.g., less than about 10 mm) In some embodiments,
the groups 802a-f can be evenly spaced along the support member
204, and in other embodiments the groups 802a-f can have any
spacing or state along the support member 204. Additionally, the
arcuate clot engagement members 802 at one group 802 can have a
different size than the arcuate clot engagement members 802 at a
different group 802. The groups 802a-f can be deployed or expanded
simultaneously (e.g., via a push-wire or other deployment methods)
or consecutively (e.g., by retracting a sheath).
[0052] FIG. 9A is a perspective view of another embodiment of a
clot treatment device 950 in a deployed state configured in
accordance with the present technology. In some embodiments, the
device 950 can include a plurality of clot engagement members 952
arranged in closely-packed circular array. The clot engagement
members 952 can be generally similar to the clot engagement members
202 and 402 described with reference to FIGS. 2A-4B. A proximal
portion of the clot engagement members 952 can be bound together
and surrounded by a tubular binding member 960. The clot engagement
members 952 can fill substantially all of a lumen of the binding
member 960, as shown in the cross-sectional view of FIG. 9B (other
than the small gaps between the clot engagement members (that are
too small for another clot engagement member)). In another
embodiment (not shown), a lumen or tube may provide for passage of
a guidewire or catheter through the bundle of clot engagement
members. Referring to FIG. 9A, the clot engagement members 952 can
have first portions 956 with differing lengths so that the second
portions 956 are spread out over a deployed engagement member
length L. In some embodiments, the deployed engagement member
length L may be between about 0.5 cm and about 8 cm, and in some
embodiments, between about 1 cm and about 5 cm. As shown in FIG.
9C, the binding member 960 can be a coil, spiral, tube, sleeve,
braid and/or other generally suitable tubular configurations. The
binding member 960 may be slotted, cut or otherwise fenestrated to
enhance flexibility. The binding member 960 may be made of various
metals, polymers and combinations thereof and may comprise
materials visible under x-ray or fluoroscopy so as to function as a
radiopaque marker to facilitate deployment, placement and
retraction by the user.
[0053] FIG. 10 is a side partial cross-sectional view of one
embodiment of a delivery system 910 for delivering the clot
treatment device 200 to a treatment site, such as a pulmonary
embolism. The delivery system 910 can include a proximal portion
911, an elongated delivery catheter 920 extending from a distal
region of the proximal portion 911, a delivery sheath 930 slidably
received within a lumen of the delivery catheter 920, a tubular
push member 940 slidably received within a lumen of the delivery
sheath 930, and a guidewire 912 slidably received within a lumen of
the push member 940. As shown in FIG. 10, the clot treatment device
200 can be positioned within the delivery sheath 930 such that the
delivery sheath 930 constrains the clot engagement members 202 in a
low-profile delivery state that is generally parallel with the
support member 204. In some embodiments, the delivery catheter 920
can have an outside diameter between about 0.8 mm and about 1.8 mm,
and in some embodiments, between about 0.1 mm and about 0.16 mm. A
proximal portion of the support member 204 can be coupled to a
distal region of the push member 204 such that axial movement of
the push member 204 causes axial movement of the support member 204
(and thus the clot treatment device 200).
[0054] The proximal portion 911 of the device can include a first
hub 922 and a second hub 932 configured to be positioned external
to the patient. The first and/or second hubs 922, 932 can include a
hemostatic adaptor, a Tuohy Borst adaptor, and/or other suitable
valves and/or sealing devices. A distal region 920a of the first
hub 922 can be coupled to the delivery catheter 920, and a proximal
region of the first hub 922 can include an opening 924 configured
to slidably receive the delivery sheath 930 therethrough. In some
embodiments, the first hub 922 can further include an aspiration
line 926 coupled to a negative pressure-generating device 928
(shown schematically), such as a syringe or a vacuum pump. A distal
region 932a of the second hub 932 can be fixed to a proximal region
of the delivery sheath 930, and a proximal region of the second hub
932 can include an opening 934 configured to receive the push
member 940 therethrough. Additionally, in some embodiments, the
second hub 932 can include a port 936 configured to receive one or
more fluids before, during and/or after the procedure (e.g.,
contrast, saline, etc.).
[0055] FIGS. 11A-11K illustrate one example for treating an
embolism (e.g., a pulmonary embolism) with the clot treatment
device 200 (and delivery system 910). FIG. 11A is a side view of a
delivery system 910 positioned adjacent to an embolism or clot
material PE within a pulmonary blood vessel V. Access to the
pulmonary vessels can be achieved through the patient's
vasculature, for example, via the femoral vein. The delivery system
910 can be guided through the right atrium, through the tricuspid
valve, into the right ventricle, through the pulmonary valve and
into the main pulmonary artery. Depending on the location of the
embolism, the delivery system 910 can be guided to one or more of
the branches of the right pulmonary artery and/or the left
pulmonary artery. It will be understood, however, that other access
locations into the venous circulatory system of a patient are
possible and consistent with the present technology. For example,
the user can gain access through the jugular vein, the subclavian
vein, the brachial vein or any other vein that connects or
eventually leads to the superior vena cava. Use of other vessels
that are closer to the right atrium of the patient's heart can also
be advantageous as it reduces the length of the instruments needed
to reach the pulmonary embolism.
[0056] As shown in FIG. 11A, the delivery sheath 930 containing the
collapsed clot treatment device 200 (not shown) can be advanced
together with the delivery catheter 920 over the guidewire 912 to
the treatment site. For example, the guidewire 912 can be inserted
through the target pulmonary embolism PE. Referring to FIG. 11B, a
distal portion of the delivery catheter 920 and/or delivery sheath
930 can then be advanced through the pulmonary embolism PE such
that the distal ends 201 of at least one group of the clot
engagement members 202 are aligned with or positioned distal to a
distal edge of the pulmonary embolism PE. In other embodiments (not
shown), a distal portion of the delivery catheter 920 and/or
delivery sheath 930 can be positioned such that the distal ends 201
of at least one group of the clot engagement members 202 are
positioned proximal to a distal edge of the pulmonary embolism
PE.
[0057] Once the device is positioned, the guidewire 912 can then be
removed proximally through a lumen of the delivery sheath 930
and/or delivery catheter 920, and the delivery sheath 930 can be
pulled proximally to a position proximal of the pulmonary embolism
PE (as shown in FIG. 11B). As shown in FIGS. 11C-11G, the delivery
sheath 930 can be retracted proximally to expose the distal
portions of the second portions 208 of the clot engagement members
such that the exposed portions radially expand and bend backwards
in a proximal direction. As the second portions 208 expand, they
extend into the pulmonary embolism PE around the device along an
arcuate path P. The arcuate path P can extend radially outward and
proximally with respect to the support member (not shown) and, as
shown in FIG. 11F, can eventually curve radially inwardly. The
second portions 208 can thus form hook-like capture elements that
penetrate into and hold clot material to the device 200 for
subsequent removal. Moreover, should the second portions 208 extend
radially outwardly enough to touch the vessel wall, the end
sections 214 of the second portions 208 form an atraumatic surface
that can abut or apply pressure to the vessel wall without damaging
the vessel wall. In some embodiments, the device presents a
plurality of arcuate members that may be substantially parallel
with the axis of the device at the point of contact with the vessel
wall when in the deployed state.
[0058] Still referring to FIG. 11F, when the delivery sheath 930 is
withdrawn proximally beyond the second portions 208 of the most
distal group of clot engagement members 202f, the first portions
206 of the clot engagement members 202f are exposed. In some
embodiments, the delivery sheath 930 can be withdrawn so as to
expose only a portion of the clot engagement members. Additionally,
in those embodiments having two or more groups of clot engagement
members, the delivery sheath 930 can be withdrawn to expose all or
some of the groups of clot engagement members. As shown in FIG.
11G, the delivery sheath 930 can continue to be withdrawn
proximally to expose additional second portions 208 and/or groups
of clot engagement members 202a-f. Clot engagement members 202a-f
may just contact or be slightly deflected by the vessel wall. If
the device is sized such that the diameter of the clot engagement
members are larger than the vessel diameter (e.g., "over-sized"),
the clot engagement members may be compressed by the vessel wall.
Thus, while fully deployed, the device may be in state of a small
amount of radial compression. In some embodiments, the device may
be diametrically over-sized by between about 5% and 50% and in
other embodiments between about 10% and 25%.
[0059] As shown in FIGS. 11H-11K, once at least a portion of the
clot engagement members and/or second portions 208 have penetrated
and engaged the targeted clot material PE, the clot treatment
device 200 can be withdrawn proximally, thereby pulling at least a
portion of the clot material PE in a proximal direction with the
device 200. For example, the push member 940, second hub 932, and
delivery sheath 930 (FIG. 10) can be retracted proximally at the
same time and rate. As such, the delivery catheter 920 can be held
in place while the delivery sheath 930, clot material PE, and clot
treatment device 200 are pulled proximally into the delivery
catheter 920. The curved shape of the second portions 208 increases
the surface area of the clot engagement members 202 in contact with
the clot material PE, thus increasing the proximal forces exerted
on the clot material. Withdrawal of the device 200 not only removes
the clot but also can increase blood flow through the vessel.
[0060] As shown in FIG. 11K, in some embodiments the delivery
catheter 920 can include an aspiration lumen (not shown) configured
to apply a negative pressure (indicated by arrows A) to facilitate
removal of the clot material PE. For example, the delivery catheter
920, delivery sheath 930 and/or clot treatment device 200 of the
present technology can be configured to be operably coupled to the
retraction and aspiration apparatus disclosed in Attorney Docket
No. 111552.8004.US00, titled "Retraction and Aspiration Apparatus
and Associated Systems and Methods," filed concurrently herewith,
which is incorporated herein by reference in its entirety. When
coupled to the retraction and aspiration apparatus, a negative
pressure is applied at or near the distal portion of the delivery
catheter 920 (via the aspiration lumen) only while the clot
treatment device 200 and/or delivery sheath 930 is being retracted.
Therefore, when retraction pauses or stops altogether, aspiration
also pauses or stops altogether. Accordingly, aspiration is
non-continuous and dependent upon retraction of the delivery sheath
930 and/or clot treatment device 200. Such non-continuous,
synchronized aspiration and retraction can be advantageous because
it reduces the amount of fluid withdrawn from the patient's body
during treatment (and thus less fluid need be replaced, if
necessary). In addition, it may be advantageous to consolidate the
steps and motions required to both mechanically transport thrombus
into the guide catheter (e.g. aspiration tube) and remove fluid
from the tube into one motion, by one person.
II. Additional Selected Embodiments of Clot Treatment Devices
[0061] FIG. 12 shows an enlarged, side view of one embodiment of a
clot treatment device 1202 (also referred to as "the device 1202")
configured in accordance with the present technology, shown in a
low-profile or delivery state and constrained within a delivery
catheter 1406. FIG. 13 shows the device 1202 of FIG. 12 in an
expanded or deployed state after removal of the delivery catheter
1406. As described in greater detail below, the clot treatment
device 1202 can be delivered to a clot at a treatment site to
restore blood flow through the clot and remove at least a portion
of the clot. Referring to FIGS. 12 and 13 together, the device 1202
can be made of a self-expanding mesh or braided material such as a
wire lattice, wire braid and/or stent. The material can be
superelastic (e.g., Nitinol) or an alternative material such as a
cobalt chrome alloy. It is believed that that porous structure of
the clot treatment device 1202 allows for the flow of blood through
the device 1202 during treatment, thus creating a lumen through the
clot material that restores significant blood flow across the
clot.
[0062] The clot treatment device 1202 can have distal ends coupled
to an atraumatic distal hub 1205 and proximal ends coupled to
proximal hub 1203. The proximal hub 1203 can be coupled to an
elongated pusher member 1201 (shown in FIG. 13), such as an
elongated rod, wire, or tubular coil. In some embodiments, the clot
treatment device 1202 can be an "over the wire" device. In such
embodiments, the pusher member 1201 can have a lumen, and the
proximal hub 1203 and/or the distal hub 1205 can have a hollow,
central lumen for receiving a guide wire. In these and other
embodiments, the distal portion of the clot treatment device 1202
can have a flexible, atraumatic member (not shown) that extends
distally from the device 1202. In yet further embodiments, the
distal hub 1205 can be tapered to better penetrate the clot
material in the vessel.
[0063] In some embodiments, the clot treatment device 1202 can have
a generally cylindrical shape that, during use, provides a flow
lumen for blood across a clot. The treatment device 1202 is not,
however, limited to a generally cylindrical shape. For example, the
shape can be generally conical, generally concave or generally
convex along its axis, so long as such shapes provide the aforesaid
lumen for blood flow.
[0064] Referring still to FIGS. 12 and 13, the clot treatment
device 1202 is compressed to fit within the diameter D.sub.L of a
lumen 1407 of the delivery catheter 1406 in the undeployed state.
In the deployed state shown in FIG. 13, the clot treatment device
1202 has a plurality of capture elements, such as a series of
radially extending capture portions 1206 which are separated from
each other by flow restoration portions 1212. The flow restoration
portions 1212 are configured to expand outwardly from the
low-profile undeployed state within the delivery catheter lumen
1407 to a first cross-sectional dimension D.sub.1 (e.g., diameter)
in the deployed state. For example, the flow restoration portions
1212 can be generally cylindrical braided sections that expand
radially outward from the undeployed stated to the deployed state.
In many applications, the first cross-sectional dimension D.sub.1
is greater than the diameter D.sub.L of the delivery catheter lumen
1407. The capture portions 1206 are configured to expand outwardly
from the low-profile undeployed state to a second cross-sectional
dimension D.sub.2 greater than the first cross-sectional dimension
D.sub.1 in the deployed state. As explained in more detail below,
the capture portions 1206 can project into the clot such that they
extend transverse to a longitudinal axis L-L of the clot treatment
device 1202, while the flow restoration portions 1212 expand
radially outward into the clot to open a passage through which
blood can quickly resume flow through the vessel. The clot
treatment device 1202 can be porous so blood flows therethrough. In
this regard, many embodiments of the clot treatment device 1202 are
made from a mesh or braided material. The material can be a
super-elastic material such as Nitinol or an alternative material
such as cobalt chrome alloy. The device can be made from a wire
lattice, wire braid or stent.
[0065] Referring again to FIG. 13, the clot treatment device 1202
can comprise a single mesh structure that is generally cylindrical
in the low-profile undeployed state (shown in FIG. 12). The series
of radially extending capture portions 1206 accordingly extend from
the same mesh as the corresponding series of flow restoration
portions 1212. The flow restoration portions 1212 can be generally
cylindrical sections in the deployed state, or in other embodiments
the flow restoration portions 1212 may taper in the distal
direction individually and/or collectively to form a conical lumen
(not shown). Each of the radially extending portions 1206 can be a
radial or otherwise transversely projecting disk that projects
outward relative to the flow restoration portions 1212.
[0066] FIGS. 14A-14F illustrate a method in accordance with the
present technology for restoring flow and removing/retrieving clot
material in a body lumen L using the clot treatment device 1202.
Access to a treatment site, such as a clot E in a pulmonary vessel,
can be achieved as described with reference to FIGS. 11A-11K. Upon
delivery of the device 1202 to the treatment site, a guidewire 1402
can be extended through the clot E in the body lumen L as shown in
FIG. 14A. As shown in FIG. 14B, a guide catheter 1404 can then be
placed over the guidewire 1402 and moved to a location where a
distal end of the guide catheter 1404 is positioned proximal to the
clot E. At this point, the guidewire 1402 can optionally be
withdrawn. However, in the embodiment shown in FIG. 14C, the
guidewire 1402 can remain positioned through the clot and a
delivery catheter 1406 can be moved through the guide catheter 1404
over the guidewire 1402 and pushed through the clot E. As shown in
FIG. 14D, the guidewire 1402 can then be withdrawn, and the clot
treatment device 1202 can be advanced distally through the delivery
catheter 1406 until it is positioned at a distal portion of the
delivery catheter 1406. Alternatively, if an over-the-wire device
configuration is used, the guidewire 1402 can be left in place
while the treatment device 1202 is deployed and retracted.
[0067] Referring to FIG. 14E, the delivery catheter 1406 can then
be retracted in a proximal direction while maintaining forward
pressure on the clot treatment device 1202 via the pusher member
1201 so that the clot treatment device 1202 becomes exposed and
released from the delivery catheter 1406. The clot treatment device
1202 can radially expands into the clot E and, some embodiments, at
least a portion of the clot treatment device 1202 expands distal of
the clot E. For example, at least one of the radially extending
capture portions 1206 of the clot treatment device 1202 is located
distal to the clot E upon expansion of the device 1202.
Additionally, the flow restoration portions 1212 between the
capture portions 1206 also expand outwardly against a portion of
the clot E to form a flow passage 1230 though the clot treatment
device 1202.
[0068] The clot treatment device 1202 accordingly restores blood
flow through the clot E immediately or at least quickly after
expanding to the deployed state as shown by arrows 1207 in FIG.
14E. More specifically, the blood freely moves through the mesh of
the clot treatment device 1202, travels through the device lumen
and exits the clot treatment device 1202 distal to the clot E. As a
result, the acute condition of blockage is mediated thus
immediately improving the circulation of oxygenated blood in the
patient.
[0069] The restoration of blood flow is anticipated to equate with
restoration of a substantial portion of the normal blood flow rate
for the patient. In less severe, e.g., "sub-massive" pulmonary
embolism patients, the clot treatment device 1202 can increase
blood flow rate by at least about 50 ml/min, at least about 150
ml/min or between about 100 to 250 ml/min. In severe, e.g.,
"massive" pulmonary embolism patients, a larger amount of the
pulmonary artery flow is compromised. Hence, in some embodiments,
at least about 500 ml/min of blood flow rate may be restored.
Moreover, at least a portion of the flow restoration is expected to
occur prior to the removal of the clot E, or any portion
thereof.
[0070] The restoration of blood flow by the clot treatment device
1202 can be achieved in a low pressure environment. For example,
the pressure in the target vessel can be less than 60 mmHg and the
blood can be venous blood, substantially non-oxygenated blood or
low oxygenated blood.
[0071] In addition to restoring blood flow, the expansion of the
clot treatment device 1202 also impinges or cuts into the clot
material. This enhances the subsequent removal of the clot E since
portions of the clot E collect (1) between the capture portions
1206; (2) through the pores of the mesh forming the radially
extending portions 1206; (3) along the longitudinal cylindrical
sections 1212 between the capture portions 1206 of the treatment
device 1202; and (4) within the clot treatment device 1202
itself.
[0072] As can be understood from the above description and the
drawing figures, the deployment of the clot treatment device 1202
results in an outwardly expanding generally cylindrical force being
urged against an inner surface of the clot E. This force pushes the
clot material outwardly and creates a lumen through which blood
flow is restored. As can also be appreciated, the presence of the
radially extending portions 1206 on the clot treatment device 1202
causes the outwardly expanding generally cylindrical force to vary
in magnitude along the axis of the clot treatment device 1202. The
force on the clot material may be greater at the locations of the
capture portions 1206.
[0073] In braided embodiments of the clot treatment device 1202,
deployment of the device leads the filaments of the braid to change
their angular orientation with respect to the axis of the device.
This angular change may improve or enhance adherence of clot
material to the clot treatment device 1202.
[0074] After the clot treatment device 1202 has been expanded and
blood flow restored, the user then retracts the clot treatment
device 1202 in a proximal direction as shown in FIG. 14F. Since the
capture portions 1206 extend transverse to the longitudinal
dimension of the vessel, the capture portions 1206 form transverse
surfaces relative to the force exerted against the clot E as the
clot treatment device 1202 is pulled in the proximal direction. The
capture portions 406 accordingly enhance the ability of the clot
treatment device 1202 to securely dislodge and retain the clot E as
the clot treatment device 1202 and the delivery catheter 1406 are
pulled back simultaneously into the guide catheter 1404. This is
followed by the entire apparatus (e.g., clot treatment device 1202,
delivery catheter 1406 and guide catheter 1404) being withdrawn
through the heart and the venous circulation and out of the
body.
[0075] As further shown in FIG. 14F, the clot treatment device 1202
may elongate as it is being withdrawn into the guide catheter 1404
due to the resistance it encounters from the presence of clot
material of the clot E. The presence of the radially extending
portions 1206 may allow elongation of the device 1202 that enhances
the capability of the device 1202 to capture the maximum amount of
clot material. This is further discussed below with respect to the
surface area and expansion ratio of preferred embodiments of the
clot treatment device 1202.
[0076] It will be appreciated that variations in the
above-described method are contemplated. For example, in certain
circumstances a guide catheter 1404 may not be necessary or
desirable and the user may choose to use only the delivery catheter
1406 for placing and manipulation of the clot treatment device
1202. As a further example, the clot may be of such a nature that
the user may desire repeat the above-described process, or at least
portions of it, in order to more fully remove the clot E or clot
material.
[0077] Referring next to FIGS. 15A-15B, it may be advantageous to
include the use of a collection or funnel catheter 1412 to assist
in the removal of the clot E. Such a funnel catheter 1412 has an
expandable portion 1414 at its distal end and may be situated
between the guide catheter 1404 and the delivery catheter 1406 or
may be part of the guide catheter 1404. In the presence of the
collection catheter 1412, the clot treatment device 1202 is pulled
proximally into the collection catheter 1412 such that the clot or
portions of it are captured within the collection catheter 1412. In
an alternative embodiment, the collection catheter 1412 can be
pushed distally over the clot treatment device 1202 and capture the
clot, or portions thereof, in that manner. If the collection
catheter 1412 is separate from the guide catheter 1404, the
collection catheter with the clot treatment device 1202 is then
pulled into the guide catheter for ultimate removal of all devices
(and the clot) from the patient.
[0078] In certain circumstances, it may be advisable to remove the
clot E without capturing it in the guide catheter 1404 or the
collection catheter 1412 (if used) and remove the clot E by
withdrawing the entire system, e.g., guide catheter 1404, delivery
catheter 1406, clot treatment device 1202 and collection catheter
1412 (if used) simultaneously.
[0079] In several embodiments, the expandable portion 1414 the
collection catheter 1412 is a conical funnel or tapered member
constructed from a mesh, braid or stent structure. Such structure
assists in retrieving and containing the clot material in the
withdrawal process. In yet further embodiments, the collection
catheter 1412 contains structural features to assist in the
expansion of the funnel portion 1414 and to hold the funnel portion
1414 open towards the wall of the blood vessel. Such features (not
shown) include interwoven support struts, self-expanding material
(e.g., Nitinol), longitudinal wire supports, stent supports,
polymeric webbing, etc.
[0080] In another embodiment of the present invention, a vacuum
apparatus can be used to aid in the removal of the clot material.
Referring to FIG. 16, a syringe 1602 is shown connected to a vacuum
manifold 1606 that is in fluid communication with the proximal end
of the guide catheter 1404. At the time the clot treatment device
1202 (and clot material) is being withdrawn into the guide catheter
1404 (or the collection catheter 1412), vacuum is applied by
pulling on the syringe. Alternative sources of vacuum 1604 are also
acceptable, e.g., a vacuum pump. A system is also contemplated
whereby vacuum is actuated automatically when the clot treatment
device 1202 (and the clot material) is being withdrawn. A
representation of the effect of the use of vacuum can be seen with
reference to FIG. 15B which shows how vacuum causes flow 1501 into
the catheter 1412.
[0081] Referring now to FIGS. 17A-17H, alternative preferred
embodiments of the clot treatment device 1202 are disclosed.
[0082] Referring to FIG. 17A, the capture portions 1206 between the
generally cylindrical flow restoration portions 1212 of the clot
treatment device 1202 are defined by a cylindrical disk shape with
a rounded triangular cross-section.
[0083] Referring to FIG. 17B, the radially extending portions 1206
between the generally cylindrical flow restoration portions 1212 of
the clot treatment device 1202 are defined by a cylindrical disk
shape with a rounded triangular cross-section wherein the diameter
of the disk increases along the length of the device 1202 thus
forming a conical exterior extent.
[0084] Referring to FIG. 17C, the capture portions 1206 between the
generally cylindrical flow restoration portions 1212 of the clot
treatment device 1202 are defined by a cylindrical disk shape with
a rectangular cross-section.
[0085] Referring to FIG. 17D, the radially extending portions 1206
between the flow restoration portions 1212 of the clot treatment
device 1202 are defined by a cylindrical disk shape with a linear
(non-rounded) triangular cross-section.
[0086] Referring to FIG. 17E, some of the capture portions 1206
between the generally cylindrical flow restoration portions 1212 of
the clot treatment device 1202 are defined by a cylindrical disk
shape with a rounded cross-section and others have a rectangular
cross section.
[0087] Referring to FIG. 17F, the radially extending portions 1206
between the generally cylindrical flow restoration portions 1212 of
the clot treatment device 1202 alternate between cylindrical disk
shape with a T-shaped cross-section and a flare-shaped
cross-section.
[0088] Referring to FIG. 17G, the radially extending portions 1206
between the generally cylindrical flow restoration portions 1212 of
the clot treatment device 1202 are defined by a partial cylindrical
disk shapes.
[0089] Referring to FIG. 17H, the radially extending portions 1206
between the generally cylindrical flow restoration portions 1212 of
the clot treatment device 1202 are defined by tabs and bumps or
protuberances arising from the cylindrical surface of the device
1202.
[0090] FIG. 18 is a cross-sectional view of another embodiment of
the clot treatment device 1202 in accordance with the technology
having an expandable member 1810, an elongated inner member 1820,
and an elongated outer member 1822. The expandable member 1810 is
configured to have an undeployed state in which the expandable
member 1810 is elongated axially to have a low profile that fits
within a delivery catheter as shown in FIG. 18. The expandable
member 1810 is further configurable into a deployed state in which
the expandable member 1810 forms a flow channel 1812 for restoring
blood flow through the region obstructed by the clot. The
expandable member 1810, for example, can be a mesh, braid,
stent-type device, or other suitable member through which blood
flows in the deployed state. In one embodiment, the expandable
member 1810 is a continuous braid formed from a shape-memory
material that has been heat set such that, in the deployed state,
the expandable member 1810 has a plurality of flow restoration
portions 1212 that expand to the first cross-sectional dimension
D.sub.1 to form the flow channel 1812 and a plurality of radially
extending portions 1206 that expand to the second cross-section
dimension D.sub.2 greater than the first cross-sectional dimension
D.sub.1. The flow restoration portions 1212 accordingly exert an
outward force (arrows 0) against clot material (not shown) to
create the flow channel 1812, and the radially extending portions
1206 accordingly exert a longitudinal force L (arrows L) against
the clot material as the clot treatment device 1202 is moved
proximally.
[0091] The elongated inner member 1820 can be a tube or coil having
inner lumen configured to receive the guidewire 1402 for
over-the-wire or rapid exchange delivery of the expandable member
1810 to the clot. The elongated outer member 1822 can be a tube or
coil having a lumen configured to receive the elongated inner
member 1820 such that the elongated inner member 1820 and/or the
elongated outer member 1822 can move relative to each other along
the longitudinal dimension of the clot treatment device 1202.
[0092] FIGS. 19 and 20 are detailed views of a distal portion 1901a
(FIG. 19) and a proximal portion 1901b (FIG. 20) of the expandable
member 1010 of the clot treatment device 1202 shown in FIG. 18.
Referring to FIG. 19, the distal portion 1901a is attached to a
distal end of the elongated inner member 1820 by the distal hub
1205. The distal hub 1205 can be blunt as described above with
reference to the embodiment of the clot treatment device 1202 shown
in FIG. 20, or the tip 405 can have a tapered distal portion 1840
configured to pass through the clot as shown in FIG. 19.
Additionally, the distal hub 1205 can have a proximal opening 1842
configured to receive the distal end of the elongated inner member
1820 and the distal end of the expandable member 1810. Referring to
FIG. 18, the proximal portion 1901b is attached to the distal end
of the elongated outer member 1822 by a proximal hub 1830. For
example, the distal and proximal portions 1901a and 1901b can be
attached to the elongated inner member 1820 and the elongated outer
member 1822, respectively, using welds, adhesives, crimping or
clamping forces, and/or other suitable attachment mechanisms.
[0093] In the operation of the clot treatment device 1202 shown in
FIGS. 18-20, the expandable member 1810 can self-expand from the
undeployed state to the deployed state without an actuator. For
example, as a delivery catheter is drawn proximally to release the
expandable member 1810, the elongated inner member 1820 can be held
in place to hold the distal portion 1901a of the expandable member
1810 distally of the clot. As the distal end of the delivery
catheter moves proximally, the elongated outer member 1822 will
slide distally as the expandable member 1810 expands until the
expandable member 1810 reaches its predetermined deployed size or
otherwise reaches equilibrium with the clot. In other embodiments,
the elongated inner member 1820 and/or the elongated outer member
1822 can be actuators that are moved proximally and/or distally to
control the radial expansion and/or the radial contraction of the
expandable member 1810.
[0094] FIGS. 21 and 22 are detailed views of the proximal and
distal portions 1901b and 1901a, respectively, of an expandable
member 1810 and other components of a clot treatment device 1202 in
accordance with another embodiment of the technology. In this
embodiment, the clot treatment device 1202 has a proximal tube 2110
(FIG. 21) and an expansion element 2120 having one end attached to
the proximal tube 2110 and another end attached to the distal
portion 1901a (FIG. 22) of the expandable member 1810. The
expansion element 2120, for example, can be a coil or spring that
is stretched from its normal state when the expandable member 1810
is the low-profile, undeployed state inside the delivery catheter.
As the distal portion 1901a and then the proximal portion 1901b of
the expandable member 1810 are released from the delivery catheter,
the expansion element 2120 contracts axially under its own stored
spring force causing the expandable member 1810 to contract axially
and expand radially outward.
[0095] In the embodiments where the expandable member 1810 is
self-expanding, the expansion element 2120 assists the expansion of
the expandable member 1810. In other embodiments, the expandable
member 1810 may not be self-expanding or may be inherently
spring-biased into the low-profile undeployed state, and the
expansion element 2120 can have enough stored energy when it is
stretched in the low-profile undeployed state to pull the distal
portion 1901a and the proximal portion 1901b of the expandable
member 1810 toward each other and thereby radially expand the
expandable member 1810.
[0096] In the foregoing embodiments, the radially extending
portions 1206 provide more surface area along the device than a
device that is uniformly cylindrical. Moreover, the radially
extending portions 1206 extend transversely to the longitudinal
dimension of the device to more effectively transfer the axial
force as the device is moved axially along the vessel after
deployment. Such increased surface area facilitates the treatment
and/or retrieval of a much larger portion of the clot E than is
generally feasible with a uniformly cylindrical device. For
example, in a preferred embodiment of the clot treatment device
1202, the device will have an external surface area between
1.5.times. and 6.times. the surface area of a uniformly cylindrical
device of the same general diameter of the cylindrical flow
restoration portions 1212. In other preferred embodiments the ratio
can be 2.times. to 4.times..
[0097] This can be advantageous particularly during retraction of
the clot treatment device 1202 through the clot E. As shown in FIG.
14F, the clot treatment device 1202 may become elongated as it is
being withdrawn through the clot E. Such elongation causes the clot
material to encounter greater surface area of the clot treatment
device 1202 than would otherwise occur with a device that was only
generally cylindrical, e.g., that did not incorporate radially
extending portions 1206. Accordingly the clot treatment device 1202
is particularly adept at capturing the maximum amount of clot
material during withdrawal.
[0098] The clot treatment device 1202 is intended for use in large
vessels, i.e., vessels with a diameter greater than 8 mm. For
example, the diameter of the pulmonary arteries typically range
from 15 to 30 mm whereas the first branches of the pulmonary
arteries typically range from 10 to 15 mm and the secondary and
tertiary branches typically range from 5 to 10 mm. At the same
time, however, it is important to minimize the size of catheter
providing access to the clot E. Accordingly, the clot treatment
device 1202 has a large expansion ratio. In a preferred embodiment
the expansion ratio from the diameter of the flow restoration
portions 1212 in the collapsed state to the expanded state will be
between 4 and 8. In another preferred embodiment the ratio will be
between 5 and 7. The large expansion ratio also enables the
formation of a flow channel in the clot E that is large, e.g., on
the order of 4-8 mm.
[0099] The radially extending portions 1206, in their fully
expanded position are intended to have a size that matches the
diameter of the target blood vessel. However, the diameters may be
slightly larger than the vessel diameter so to apply greater radial
force against the blood vessel (without causing trauma) in those
circumstances when it is desirable to improve clot collection.
Similarly, in those circumstances where there is a concern of
creating trauma on delicate blood vessels, the radially extending
portions 1206 may have a diameter that is smaller than the vessel
diameter. It is contemplated that different sizes of the device
1202 will be available for selection by the user for a particular
presentation of the patient.
[0100] As for the length of the clot treatment device 1202, it is
known that a typical pulmonary embolism will have a length within
the range between about 2 cm and 10 cm and sometimes between about
1 cm and 20 cm. Accordingly, in a preferred embodiment, the clot
treatment device 1202 will have a length that exceeds the length of
the embolism so that a portion of the clot treatment device is
positioned distal of the clot E during expansion.
[0101] With regard to the delivery catheter 1406, in a preferred
embodiment for use with a pulmonary embolism, the size will be
around 1 F-6 F. Smaller diameters will pass through the clot 100
more easily. In addition, the delivery catheter 1406 may have
stiffness characteristics to assist in making sure the delivery
catheter 1406 passes through the clot in a smooth manner. Such
stiffness characteristics include self-expanding Nitinol wire
braids or stent structures that are contained within the structure
of the delivery catheter 1406. The delivery catheter 1406 also has
sufficient flexibility so that it may carry the clot treatment
device 1202 and still pass through a tortuous vessel path as
described above starting with insertion of the delivery catheter
1406 in the femoral vein FV.
[0102] In some preferred embodiments, the method and device in
accordance with the present invention may reduce the Mean Resting
Pulmonary Artery Pressure (MRPAP). Upon at least partial relief
from the clot 100, MRPAP may be reduced by about 20-50 mmHg to a
normal range of 8-20 mmHg. In some embodiments, the reduction in
MRPAP may be about 25-50%. In some embodiments, the reduction in
MRPAP may be about 15% to 40% and in other embodiments between
about 30% and 75%.
[0103] Such a reduction in MRPAP can occur in two steps. A first
step is when the clot treatment device 1202 is first deployed and
blood flow is at least partially restored. A second step may be
when the clot treatment device 1202 is retracted and at least some
of the clot E is removed from the vessel. A third step may be after
the clot treatment device 1202 has been removed and the effect of
the body's own processes and/or thrombolytic drugs that may have
been used before, during or after the procedure take effect upon
clot that has been disrupted by the clot treatment device.
[0104] FIG. 15 is a side view of an embodiment of a guide catheter
1500 for use with any of the foregoing embodiments of the clot
treatment devices 1202 (not shown in FIG. 23). The guide catheter
2300 can include a shaft 2302 having a sufficiently large lumen to
accommodate the delivery catheter 1406 (FIGS. 12 and 14A). The
guide catheter 2300 can further include an expandable guide member
2310 at the distal end of the shaft 2302 configured to expand
radially outward to contact or nearly contact the vessel wall VW.
The guide member can be formed from a permeable, radially expanding
material, such as a mesh or other macroporous structure (e.g., a
braid of wires or filaments). The guide member 2310, for example,
may be formed from a tubular braid of elastic or super-elastic
filaments such as Nitinol that has been heat set into the desired
expanded shape. The permeable, radially expanding guide member 2310
may have advantages over an occlusive member such as a balloon or
impermeable funnel. For example, the guide member 1510 allows a
substantial amount of blood flow BF to continue flowing through the
blood vessel where therapy is being directed. In addition, the
guide member 2310 positions the shaft 2302 and delivery catheter
606 at or near the center of the vessel. The clot treatment device
1202 (not shown in FIG. 23) may also be substantially
self-centering upon deployment, and the guide member 2310 may
further guide the clot material captured by the clot treatment
device 1202 into the shaft 2302 as the clot treatment device 1202
moves into proximity of the distal end of the shaft 2302. This is
expected to enhance aspiration of the clot material. For example,
in the embodiment shown in FIG. 23, the radially expanding guide
member 2310 has a funnel shape adjacent the distal end of the shaft
2302 to guide thrombus material into the distal opening of the
shaft 2302 where it can be more readily aspirated.
[0105] The radially expanding guide member 2310 may also be formed
by conventional machining, laser cutting, electrical discharge
machining (EDM) or other means known in the art to make a
fenestrated, mesh or porous structure that can be affixed near the
distal end of the shaft 2302. In some embodiments the radially
expanding guide member 2310 may self-expand, but in other
embodiments it may be actuated by an operator using, for example,
electrical or electromechanical means. By having a porous radially
expanding guide member 2310, the guide catheter 2300 may be
substantially centered within a vessel without blocking a large
portion of the flow around the catheter. In some embodiments, the
radially expanding guide member 2310 may block less than about 50%
of the flow about the catheter and in other embodiments less than
about 25% of the flow. When the guide member 2310 is made with a
braid of filaments (e.g. wires), it may be formed from a tubular
braid. In some embodiments, the tubular braid may be formed with
approximately 12 to approximately 144 filaments, or in other
embodiments from about 36 to about 96 filaments. The pores as
measured by the largest circle that can be inscribed within an
opening of the mesh may be between about 0.5 mm and 5 mm.
[0106] FIGS. 24 and 25 show additional embodiments of guide members
2410 and 2510, respectively, that can be used instead of or in
addition to the guide member 2310. Referring to FIGS. 23 and 24,
one or both ends of the tubular braid of the guide members 2310 and
2410 may be inverted and attached to the catheter body. Referring
to FIG. 25, neither end of the guide member 2510 is inverted. With
the distal end inverted, it advantageously may form a funnel
adjacent the distal opening of the catheter that may enhance clot
capture and aspiration.
[0107] FIG. 26 shows an embodiment of a guide catheter 2600 having
a shaft 2602 and a guide member 2610 in accordance with another
embodiment of the technology. In the embodiment shown in FIG. 26,
the guide member 2610 has a tapered or funnel shape, and includes a
non-permeable portion 2612 and a permeable portion 2614. The
permeable portion 2614 can comprise a flared radially expanding
mesh that has, at least in part, a tapered or funnel shape, and the
non-permeable portion 2612 may have a substantially non-porous or
otherwise non-permeable material or coating over the mesh.
Preferably, the non-permeable material is a highly elastic material
such as polyurethane, silicone, latex rubber and the like so that
it can flex with the expansion of the mesh. In some embodiments,
the non-permeable material covers a proximal portion of the mesh as
shown in FIG. 26. The non-permeable portion 2612 may divert some
flow away from the distal end of the catheter. The covering may
cover a portion of the mesh to a diameter "d". In some embodiments,
the diameter d of the covering is less than about 75% of the
diameter "D" of the mesh funnel. In some embodiments, the diameter
d may be less than about 50% of diameter D. The concept of a
non-permeable material can also be applied to the guide catheter
2300 shown above in FIG. 23. For example, the expandable guide
member 2310 of the guide catheter 2300 can have a non-permeable
portion 2312 at the proximal portion of the expandable guide member
2310 similar to the non-permeable portion 2612 shown and described
with reference to FIG. 26.
[0108] In any of the above embodiments shown and/or described
herein, the clot treatment device and/or delivery system can be
configured to facilitate maceration, fragmentation and/or
disruption of the clot material. For example, unsheathing and
re-sheathing the clot treatment device via advancement and
retraction of the delivery catheter and/or the guide catheter can
macerate the clot material held by the clot treatment device. As
the guide catheter and/or delivery catheter slide across the outer
layer of the clot material, the guide catheter and/or delivery
member causes a repeated shear stress on the outer layer of the
clot material that can weaken and/or fragment the clot and/or
slough off outer layers of the clot. Moreover, retracting a clot
having a larger diameter than the guide catheter and/or delivery
catheter (or at the very least, having a portion that extends
beyond the diameter of the guide catheter and/or delivery catheter)
shears the clot material as it enters the guide catheter and/or
delivery catheter, thus fragmenting the clot and releasing embolic
particles from the main clot mass. In those embodiments where the
clot treatment device and/or delivery system do not include a
distal filter or embolic protection device, the released embolic
particles are allowed to freely flow in the direction of the blood
flow without being captured by a downstream device. It is expected
that such restored blood flow causes natural lysis of the embolic
particles.
III. Examples
[0109] Several examples of the present technology are as
follows:
[0110] 1. A clot treatment device for treating a pulmonary embolism
within a blood vessel, the clot treatment device being moveable
between a low-profile undeployed state and a deployed state, the
clot treatment device comprising: [0111] a support member
configured to extend through a delivery catheter, wherein the
support member has a proximal portion and a distal portion; [0112]
a plurality of clot engagement members positioned circumferentially
about at least an area of the distal portion of the support member,
wherein individual clot engagement members have a curved portion;
[0113] wherein the clot engagement members are configured to
penetrate clot material along an arcuate path and mechanically
macerate clot material and release embolic particles when
re-sheathed into the delivery catheter.
[0114] 2. The clot treatment device of example 1 wherein, in the
deployed state, individual curved portions of the clot engagement
members project radially outwardly relative to the support member
in a curve that has a proximally extending section which defines a
proximally facing concave portion, and wherein the individual
curved portions further include an end section that curves radially
inwardly from the proximally extending section.
[0115] 3. A method of treating a pulmonary embolism, comprising:
[0116] accessing a venous vessel of a patient; [0117] inserting a
catheter in the vessel and urging the catheter through the vessel,
through chambers of the patient's heart and into a pulmonary artery
until a distal end of the catheter is located at a region distal of
a pulmonary embolism; [0118] delivering a treatment device having a
plurality of radially extending members through the catheter;
[0119] disturbing the embolus by mechanical maceration of the
embolus to release embolic particles without capturing the embolic
particles in an embolic protection device; and [0120] establishing
one or more blood flow channels through the embolus wherein the one
or more blood flow channels facilitate natural lysis of the
embolus.
[0121] 4. A method of treating a pulmonary embolism comprising:
[0122] delivering an embolectomy device through the heart to a
pulmonary embolism that at least partially restricts blood flow
through a pulmonary vessel, wherein the embolectomy device
comprises an expandable cylindrical section and a radial expansion
member configured to expand outwardly from the cylindrical section;
[0123] deploying the embolectomy device within the pulmonary
embolism so as to restore blood flow through said pulmonary
embolism, [0124] wherein deploying the embolectomy device comprises
expanding the cylindrical section within the pulmonary embolism
such that the cylindrical section forms an expanded flow channel
through the pulmonary embolism and expanding the radial expansion
member to a greater extent than the cylindrical section, and
wherein at full expansion of the cylindrical member the radial
expansion member projects outward from the cylindrical member;
[0125] fragmenting the pulmonary embolism while moving the
embolectomy device and at least a portion of the pulmonary embolism
along the pulmonary vessel; and [0126] withdrawing the embolectomy
device and at least a portion of the pulmonary embolism from the
pulmonary vessel.
[0127] 5. A device for treating a pulmonary embolism that at least
partially restricts blood flow through a pulmonary vessel, the
device comprising: [0128] an elongated shaft having a proximal
region and a distal region; [0129] an expandable braid attached to
the distal region of the elongated shaft, the braid having a
plurality of radially extending portions and at least one
cylindrical portion, and the radially extending portions and the
cylindrical portion being configured to move from a compressed
state sized to fit in a delivery catheter to an expanded state;
[0130] wherein the cylindrical portion is between a pair of the
radially extending portions, and in the expanded state the
cylindrical portion is configured to press radially outward against
the pulmonary embolism; [0131] wherein the radially extending
portions extend radially outward from the cylindrical portion in
the expanded state such that portions of the pulmonary embolism are
retained between the radially extending portions; and [0132]
wherein the cylindrical portion has a first length along a
longitudinal direction of the braid in the expanded state and the
radially extending portions have a second length along the
longitudinal direction of the braid in the expanded state that is
less that the first length; and [0133] wherein the radially
extending portions and/or the cylindrical portions are configured
to elongate and/or contract when re-sheathed into the delivery
catheter to mechanically macerate clot and release embolic
particles.
[0134] 6. The device of example 1 wherein at least a portion of the
individual radially extending portions is disk-shaped.
[0135] 7. The device of example 1 wherein the individual radially
extending portions include a curved portion and a linear
portion.
[0136] Although the invention has been described in terms of
particular embodiments and applications, one of ordinary skill in
the art, in light of this teaching, can generate additional
embodiments and modifications without departing from the spirit of
or exceeding the scope of the exampled invention. Accordingly, it
is to be understood that the drawings and descriptions herein are
proffered by way of example to facilitate comprehension of the
invention and should not be construed to limit the scope
thereof.
* * * * *