U.S. patent application number 17/367838 was filed with the patent office on 2021-12-30 for double-lumen infusion catheter with infusion lumen widened along intermediate section thereof.
The applicant listed for this patent is AV Medical Technologies Ltd.. Invention is credited to Ilan Carmel, Josef Shahrur, Michael Gabriel Tal.
Application Number | 20210402080 17/367838 |
Document ID | / |
Family ID | 1000005836136 |
Filed Date | 2021-12-30 |
United States Patent
Application |
20210402080 |
Kind Code |
A1 |
Tal; Michael Gabriel ; et
al. |
December 30, 2021 |
DOUBLE-LUMEN INFUSION CATHETER WITH INFUSION LUMEN WIDENED ALONG
INTERMEDIATE SECTION THEREOF
Abstract
Double-lumen infusion catheter including: a shaft having
proximal section, distal section, and intermediate section
therebetween; first and second lumens extending along a length of
the shaft and having arc shaped wall therebetween; and an
inflatable member provided distally to intermediate section, and
over the distal section. First lumen has cross section larger than
cross section of second lumen and is configured to receive a
guidewire therethrough and allow fluid flow via an unobstructed
portion of first lumen. Unobstructed portion is formed along
guidewire outer surface, between guidewire outer surface and inner
wall of first lumen, and extends from an inlet at proximal end of
intermediate section to an outlet at distal end of intermediate
section. First lumen is narrowed to approximate a first diameter in
shaft proximal and distal sections, and is widened to approximate a
second diameter greater than first diameter in the shaft
intermediate section.
Inventors: |
Tal; Michael Gabriel;
(Woodbridge, CT) ; Carmel; Ilan; (Tel Mond,
IL) ; Shahrur; Josef; (Pardes Hanna-karkur,
IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
AV Medical Technologies Ltd. |
Tel-Aviv |
|
IL |
|
|
Family ID: |
1000005836136 |
Appl. No.: |
17/367838 |
Filed: |
July 6, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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15430776 |
Feb 13, 2017 |
11052188 |
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17367838 |
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14760774 |
Jul 14, 2015 |
10363358 |
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PCT/US2014/010752 |
Jan 8, 2014 |
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15430776 |
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61752649 |
Jan 15, 2013 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61M 25/0075 20130101;
A61M 25/09041 20130101; A61M 25/104 20130101; A61M 2025/0076
20130101; A61M 2025/0079 20130101; A61M 2025/1052 20130101; A61M
25/003 20130101; A61M 5/14 20130101; A61M 25/0052 20130101; A61M
25/008 20130101; A61M 2025/0018 20130101; A61M 2025/0081 20130101;
A61M 2210/12 20130101; A61M 2025/091 20130101 |
International
Class: |
A61M 5/14 20060101
A61M005/14; A61M 25/00 20060101 A61M025/00; A61M 25/10 20060101
A61M025/10; A61M 25/09 20060101 A61M025/09 |
Claims
1-14. (canceled)
15. A double-lumen infusion catheter comprising: a shaft including
an outer wall and an inner wall defining a first lumen and a second
lumen; a proximal guidewire opening in communication with the first
lumen configured to receive a guidewire; a proximal infusion
opening in fluid communication with the first lumen, wherein the
first lumen is configured to receive a guidewire from the guidewire
opening therethrough and to allow fluid from the proximal infusion
opening to flow along the guidewire; a distal infusion opening in
fluid communication with the first lumen configured to output the
fluid to flow at first flow rate; a distal guidewire opening in
fluid communication with the first lumen, the distal guidewire
opening configured to output the fluid to flow at a second flow
rate that is lower than the first flow rate; an inflatable member
disposed at a distal section of the shaft, the inflatable member in
fluid communication with a distal end portion of the second lumen;
and an inflation opening in fluid communication with a proximal end
portion of the second lumen.
16. The double-lumen infusion catheter according to claim 15,
wherein the first lumen includes a distal wall segment adjacent the
distal guidewire opening having a textured surface configured to
build a pressure gradient of the fluid passing through the distal
guidewire opening.
17. The double-lumen infusion catheter according to claim 15,
wherein the distal infusion opening is disposed on the shaft
between the proximal infusion opening and the distal guidewire
opening.
18. The double-lumen infusion catheter according to claim 15,
wherein the distal guidewire opening is configured to passthrough
the guidewire.
19. The double-lumen infusion catheter according to claim 15,
wherein the first lumen includes a proximal wall segment adjacent
the proximal guidewire opening having a textured surface configured
to build a pressure gradient of the fluid passing through the
proximal guidewire opening.
20. The double-lumen infusion catheter according to claim 16,
wherein the proximal guidewire opening is configured to output the
fluid to flow at a third flow rate that is lower than the first
flow rate.
21. The double-lumen infusion catheter according to claim 16,
wherein the shaft includes a proximal section, a distal section,
and an intermediate section between the proximal section and distal
section.
22. The double-lumen infusion catheter according to claim 21,
wherein the first lumen is narrowed to a first diameter at the
proximal section and along an entire length of the distal
section.
23. The double-lumen infusion catheter according to claim 22,
wherein the first lumen is narrowed to the first diameter along an
entire length of the distal section.
24. The double-lumen infusion catheter according to claim 23,
wherein the first lumen is widened to a second diameter greater
than the first diameter in the intermediate section.
25. A double-lumen infusion catheter comprising: a shaft including
an outer wall and an inner wall defining a first lumen and a second
lumen; a proximal guidewire opening in communication with the first
lumen configured to receive a guidewire; a proximal infusion
opening in fluid communication with the first lumen, wherein the
first lumen is configured to receive a guidewire from the guidewire
opening therethrough and to allow fluid from the proximal infusion
opening to flow along the guidewire; a proximal guidewire opening
seal configured block the fluid from flowing proximally of the
proximal guidewire opening; a distal infusion opening in fluid
communication with the first lumen; a distal guidewire opening in
fluid communication with the first lumen; an inflatable member
disposed at a distal section of the shaft, the inflatable member in
fluid communication with a distal end portion of the second lumen;
and an inflation opening in fluid communication with a proximal end
portion of the second lumen.
26. The double-lumen infusion catheter according to claim 25,
wherein the proximal guidewire opening seal is an inflatable seal
disposed adjacent and in fluid communication with the proximal
infusion opening.
27. The double-lumen infusion catheter according to claim 26,
wherein the inflatable seal includes a seal inlet configured to
receive the fluid entering the proximal infusion thereby inflating
the inflatable seal.
28. The double-lumen infusion catheter according to claim 25,
further comprising: a distal guidewire opening seal configured
block the fluid from flowing distally the distal guidewire
opening.
29. The double-lumen infusion catheter according to claim 28,
wherein the distal guidewire opening seal is an inflatable seal
disposed adjacent and in fluid communication with the distal
infusion opening.
30. The double-lumen infusion catheter according to claim 29,
wherein the inflatable seal includes a seal inlet configured to
receive the fluid entering the distal infusion thereby inflating
the inflatable seal.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 15/430,776, filed on Feb. 13, 2017, now U.S.
Pat. No. 11,052,188, which is a continuation of U.S. patent
application Ser. No. 14/760,774, filed on Jul. 14, 2015, now U.S.
Pat. No. 10,363,358, which is a National Stage Entry of PCT Patent
Application No. PCT/US2014/010752 filed on Jan. 8, 2014, which
claims the benefit of and priority to U.S. Provisional Patent
Application No. 61/752,649, filed on Jan. 15, 2013. The entire
contents of each of the foregoing applications are incorporated by
reference herein.
BACKGROUND OF THE INVENTION
[0002] The present invention, in some embodiments thereof, relates
to medical devices, and in particular to balloon catheters
applicable for treating blood vessels.
[0003] Balloon catheters are well known and used in treating
various conditions in blood vessels. Two main types of balloon
catheters in that area are dilatation balloon catheter, used to
treat narrowed or stenotic portions of the vessel and recover flow
(e.g., angioplasty balloon catheters), and occlusion balloon
catheters, used to temporarily block flow out of a vessel segment
while infusing fluid (e.g., medicament, contrast enhancer or
flushing material) therein.
[0004] Some balloon catheters have at least three parallel
functions, including: balloon inflation, travel over a guide wire,
and infusion or dispersion of fluids therethrough. Such balloon
catheters often include at least three lumens passing there along,
including an inflation lumen, a guidewire lumen and an infusion
lumen, correspondingly. In some occasions it is suggested to treat
a blood vessel with a balloon catheter comprising an infusion exit
opening located proximally to the balloon member, particularly if
the balloon member is used for occlusion at least partially during
infusion. U.S. Pat. No. 7,182,755 describes a use of an occlusion
balloon catheter with a proximal infusion opening for treating
hemodialysis vascular access. U.S. Pat. No. 5,368,567 describes a
dilatation balloon catheter with a proximal infusion opening. The
disclosures of both patents are fully incorporated herein by
reference.
[0005] In some such occasions, minimization of catheter's lumens
cross-sections is advantageous. In one example, there may be a need
for a small diameter catheter for intraluminal passage (e.g., 3 F
to 5 F) so it is more complex to introduce three lumens. In a
second example, there may be a need to fortify the catheter shaft
for high pressure dilatations (as in vascular access recanalization
in certain anatomies), so it may be advantageous to decrease
overall lumens size in a certain shaft diameter.
SUMMARY OF THE INVENTION
[0006] The present disclosure relates to a PTA (percutaneous
transluminal angioplasty) balloon catheter, preferably
high-pressure type, optionally introducible as an over the wire
catheter. The catheter possess the attribute of injecting fluid to
the treated site through a dedicated opening proximal to the
balloon member, for introduction of fluids such as contrast
enhancing material and/or medication. Fluid injection can be
performed simultaneously while inflating or deflating the balloon,
or while balloon is maintained inflated. Possibly, number of
radiopaque markings (preferably two or more) is present to define
the working length of the balloon and facilitate in balloon
placement. In some embodiments, a single lumen is used, at least in
part, both for fluids transfer and dispersion ("infusion") as well
as for guide wire passage. In some such embodiments, a valve
mechanism is used to sustain selective operability of the lumen so
that fluids will disperse mostly or solely through the proximal
dispersion opening rather than the guide wire distal exit opening.
In one example, the catheter ends with a tip, optionally an
atraumatic tip with a check-valve integrated inside the guide wire
lumen distal to the injection opening to allow infusion of fluids
with or without the guide wire. Such a device can be used for
multiple functions in sequence and/or in parallel, such as:
performing high-pressure angioplasty in native arteriovenous
dialysis fistulae or synthetic grafts; perform balloon dilatation
and simultaneous contrast material injection; using smaller amounts
of contrast enhancing material; decreasing use of angiograms and
radiation exposure to staff and patient.
[0007] Catheters according to the present disclosures may be used
also for embolectomy and declotting procedures. A device according
to the present invention may include, though not necessarily, a
relatively soft and compliant balloon fixed at the distal tip. The
catheter possess the attribute of injecting fluid to the treated
site through a dedicated opening proximal to the balloon for
introduction of fluids such as clot dissolving material (such as
t-PA). Fluid injection can be performed simultaneously while
inflating or deflating the balloon, or while balloon is maintained
inflated. Such a device can be used for multiple functions in
sequence and/or in parallel, such as: performing balloon occlusion
(possibly following dilatation) and simultaneous clot dissolving
fluid injection; reducing the risk of clot migration to the
arterial side during thrombectomy procedure and injection of
contrast to the clogged access; using smaller amounts of contrast
enhancing material; decreasing use of angiograms and radiation
exposure to staff and patient.
[0008] According to an aspect of some embodiments of the present
invention there is provided a catheter comprising a shaft, having a
length, a proximal end and a distal end, and a wall enclosing an
infusion lumen extending along the length and opened at both
proximal and distal ends with corresponding proximal opening and
distal opening. The infusion lumen is further opened with a lateral
infusion opening disposed in the wall between the proximal end and
distal end. The catheter also includes an inflatable member
connected to the shaft adjacent the distal end and distal to the
lateral infusion opening, and an inflation lumen sealed to the
infusion lumen, extending between a proximal inflation opening at
the proximal end and a distal inflation port opened to an interior
of the inflatable member. A valving mechanism is selectively
operable to block the distal opening thereby allowing infusion exit
mostly or solely through the lateral infusion opening rather than
mostly or solely through the distal opening.
[0009] A method for operating the catheter includes at least one of
the following steps (not necessarily in same order):
[0010] 1. inserting a guidewire in a luminal vessel;
[0011] 2. delivering the catheter in the luminal vessel over the
guidewire to a chosen target;
[0012] 3. inflating the inflatable member to occlude the luminal
vessel at the target; and
[0013] 4. infusing a fluid through the lateral infusion opening
proximal to the inflatable member such that no fluid passes beyond
the inflatable member.
[0014] In some embodiments, the infusing occurs while the
inflatable member is filled. Optionally, the method comprises a
step of deflating the inflatable member after the infusing.
Optionally, inflating the balloon generates a dilatation force in a
magnitude above a mechanical yield point of a stenotic blood vessel
wall.
[0015] In an aspect of some embodiments according to the present
invention, there is provided a catheter which comprises an infusion
wall enclosing an infusion lumen. In some embodiments the infusion
lumen extends axially along the infusion wall, and comprises a
proximal wall segment, a distal wall segment and an intermediate
wall segment extending therebetween. In some embodiments, the
proximal wall segment comprises a proximal guidewire opening and
the distal wall segment comprises a distal guidewire opening. In
some embodiments, the intermediate wall segment adjoins the distal
wall segment with a narrowing. In some embodiments, the
intermediate wall segment includes a fluid inlet appositional to
the proximal wall segment and a fluid outlet appositional to the
distal wall segment. In some embodiments, the proximal wall segment
adjoins the intermediate wall segment with a widening. The
narrowing and/or widening may be gradual.
[0016] In some embodiments, the infusion lumen in distal wall
segment is sized, shaped, and/or inner surface of the distal wall
segment is textured, such, to build a distal pressure gradient
allocating a distal flow rate through the distal guidewire opening
being 40% or less a fluid outlet flow rate through the fluid
outlet, optionally 20% or less, optionally 10% or less, optionally
5% or less, optionally 2% or less. In some embodiments, the
infusion lumen in proximal wall segment is sized, shaped, and/or
inner surface of the proximal wall segment is textured, such, to
build a proximal pressure gradient allocating a negative flow rate
through the proximal guidewire opening being 40% or less a fluid
outlet flow rate through the fluid outlet, optionally 20% or less,
optionally 10% or less, optionally 5% or less, optionally 2% or
less.
[0017] Optionally, the distal wall segment and/or the proximal wall
segment is unobstructed, such as with a wire passing therein.
Optionally and alternatively, the distal wall segment and/or the
proximal wall segment is obstructed, partially or fully, with a
guidewire, optionally a 0.035'' guidewire, or optionally with a
0.025'' guidewire, or optionally a 0.018'' guidewire, or optionally
with a 0.014'' guidewire, or any other size, higher, lower or of an
intermediate size.
[0018] In some embodiments, a cross section area of the fluid
outlet divided by a cross section area of the distal guidewire
opening is at least 1.2, optionally at least 1.5, optionally at
least 2, optionally at least 5, optionally at least 10, or higher,
or lower, or intermediate. Optionally, the distal wall segment is
at least 10 mm in length, optionally at least 20 mm, optionally at
least 50 mm, optionally at least 100 mm, or higher, or lower, or
intermediate. In some embodiments, the distal pressure gradient is
determined according to an infusion fluid viscosity of at least 0.5
centipoises, optionally at least 0.65 centipoises, optionally at
least 3 centipoises, optionally at least 8 centipoises, optionally
at least 14 centipoises, or higher, or lower, or intermediate.
[0019] In some embodiments, a cross section area of the proximal
guidewire opening is equal to or less than a cross section area of
the distal guidewire opening. In some embodiments, a cross section
of the infusion lumen in the distal wall segment and/or in the
proximal wall segment is circular and 0.3 to 1.5 mm in diameter,
optionally 0.9 to 1 mm in diameter, optionally 0.3 to 0.9 mm in
diameter. In some embodiments, a cross section of the infusion
lumen in the intermediate wall segment is noncircular shaped with a
smallest distance between antipodal points at an inner boundary
thereof being at least 0.5 mm. Optionally, a cross section of the
infusion lumen in the intermediate wall segment is crescent shaped
with a smallest distance between two opposing arcs at an inner
boundary thereof being at least 0.5 mm. Optionally, a cross section
area of the infusion lumen in the intermediate wall segment is at
least 1.5 mm2, optionally at least 1.75 mm2, optionally at least 2
mm2.
[0020] In some embodiments, the fluid outlet includes at least one
opening such as a hole and/or at least one slit which may be
configured to open above a predetermined infusion pressure of at
least 1 bar, optionally of at least 2 bars.
[0021] In some embodiments, the catheter also includes an
inflatable member and an inflation wall enclosing an inflation
lumen, with the infusion wall, along a length thereof. The
inflatable member may be a dilatation balloon comprising a
non-compliant or a semi-compliant material, or, optionally and
alternatively, a non-compliant material. In some embodiments, the
inflatable member is provided in between the fluid outlet and the
distal guidewire opening. Optionally and alternatively, the fluid
outlet includes a proximal-most opening and a distal-most opening,
wherein the inflatable member extends therebetween.
[0022] In some embodiments, a guidewire seal is provided in the
infusion lumen between the fluid inlet and the proximal guidewire
opening and/or between the fluid outlet and the distal guidewire
opening. Optionally, the guidewire seal allows a guidewire travel
therethrough. Optionally, the guidewire seal is annular shaped and
inflatable to decrease in inner diameter below to a predetermined
guidewire diameter. Optionally, alternatively or additionally, a
zero seal is provided between the fluid inlet and the proximal
guidewire opening and/or between the fluid outlet and the distal
guidewire opening. Optionally, the zero seal is normally closed to
fluid flow at the absence of a guidewire passing therethrough.
[0023] In some embodiments, the fluid outlet includes a single
opening with a total opened area being equal to or greater than the
cross section area of infusion lumen proximal to the fluid outlet
less a cross section area of a guidewire with a minimal prescribed
diameter. Optionally, a structural fortification is added to the
infusion wall about the opening. Optionally, the fortification
includes a mesh patch, a tube insert or a sheet insert.
[0024] In one specific implementation, a catheter has an infusion
wall enclosing an infusion lumen extending axially therealong. The
infusion lumen includes three segments: a proximal wall segment, a
distal wall segment and an intermediate wall segment extending
therebetween. The proximal wall segment comprises a proximal
guidewire opening and the distal wall segment comprises a distal
guidewire opening so that a guidewire may be positioned within the
infusion lumen. The intermediate wall segment adjoins the distal
wall segment with a narrowing such that the distal wall segment has
a smaller minimal cross sectional area than a minimal cross
sectional area of said intermediate wall segment. When a guidewire
is positioned in the infusion lumen, it fits tighter in the distal
wall segment of the infusion lumen than it does in the larger
intermediate wall segment. The narrowed distal wall segment is
narrowed for a length of at least 20 mm. This effectively seals the
distal end of the catheter, while at the same time allowing fluid
to relatively freely migrate from a fluid inlet in the intermediate
wall segment, around the guidewire in the intermediate wall
segment, and out of a fluid outlet in the intermediate wall
segment. In some embodiments, the cross sectional area of the fluid
outlet is equal to or greater than the minimal cross sectional area
of the intermediate wall segment minus the minimal cross sectional
area of the distal wall segment. In some embodiments, a similar at
least 20 mm length of narrowed portion of the infusion lumen is
positioned on the proximal side of the catheter as well.
[0025] Unless otherwise defined, all technical and/or scientific
terms used herein have the same meaning as commonly understood by
one of ordinary skill in the art to which the invention pertains.
Although methods and materials similar or equivalent to those
described herein can be used in the practice or testing of
embodiments of the invention, exemplary methods and/or materials
are described below. In case of conflict, the patent specification,
including definitions, will control. In addition, the materials,
methods, and examples are illustrative only and are not intended to
be necessarily limiting.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Some embodiments of the invention are herein described, by
way of example only, with reference to the accompanying drawings.
With specific reference now to the drawings in detail, it is
stressed that the particulars shown are by way of example and for
purposes of illustrative discussion of embodiments of the
invention. In this regard, the description taken with the drawings
makes apparent to those skilled in the art how embodiments of the
invention may be practiced.
[0027] In the drawings:
[0028] FIGS. 1A-D schematically illustrate an exemplary balloon
catheter comprising a combined infusion-guidewire lumen with
selective valving mechanism, in accordance with embodiments of the
present invention;
[0029] FIGS. 2A-B schematically illustrate portions in cross
section of an exemplary balloon catheter and seals provided
therein, in accordance with embodiments of the present
invention;
[0030] FIGS. 3A-B schematically illustrate portions in cross
section of a different exemplary balloon catheter and seals
provided therein, in accordance with embodiments of the present
invention;
[0031] FIGS. 4A-B schematically illustrate cross sections in
portions of two different exemplary catheters comprising combined
infusion-guidewire lumen, in accordance with embodiments of the
present invention;
[0032] FIGS. 5A-H schematically illustrate cross sections in
portions of different exemplary catheters, in accordance with
embodiments of the present invention;
[0033] FIGS. 6A-B schematically illustrate an exemplary infusion
lumen comprising a first exemplary valving mechanism, in accordance
with embodiments of the present invention;
[0034] FIGS. 7A-B schematically illustrate balloon catheter
incorporating exemplary valving mechanisms differentiated by
balloon location relative to fluid outlet, in accordance with
embodiments of the present invention;
[0035] FIGS. 8A-B schematically illustrate an exemplary infusion
lumen comprising an exemplary valving mechanism with an additional
exemplary backflow seal, in accordance with embodiments of the
present invention;
[0036] FIGS. 9A-B schematically illustrate an exemplary infusion
lumen comprising an exemplary valving mechanism with additional
exemplary proximal and distal sealing sets, in accordance with
embodiments of the present invention;
[0037] FIGS. 10A-I illustrate side views and cross section views of
an exemplary angioplasty infusion balloon catheter comprising a
guidewire based valving mechanism, in accordance with embodiments
of the present invention;
[0038] FIGS. 11A-C schematically illustrate different exemplary
cross section shapes for an intermediate section of an infusion
lumen, in accordance with embodiments of the present invention;
[0039] FIGS. 12A-C schematically illustrate different exemplary
fluid outlet types and/or distribution, in accordance with
embodiments of the present invention;
[0040] FIGS. 13A-B schematically illustrate cut views of an
exemplary balloon catheter with a single proximal fluid outlet
comprising a first exemplary fortification, in accordance with
embodiments of the present invention;
[0041] FIGS. 14A-B schematically illustrate cut views of an
exemplary balloon catheter with a single proximal fluid outlet
comprising a second exemplary fortification, in accordance with
embodiments of the present invention; and
[0042] FIGS. 15A-B schematically illustrate cut views of an
exemplary balloon catheter with a single proximal fluid outlet
comprising a third exemplary fortification, in accordance with
embodiments of the present invention.
DESCRIPTION OF EMBODIMENTS OF THE INVENTION
[0043] The following preferred embodiments may be described in the
context of exemplary balloon catheters for treating blood vessels.
However, the invention is not limited to the specifically described
devices and methods, and may be adapted to various clinical
applications without departing from the overall scope of the
invention.
[0044] Referring to the drawings, FIGS. 1A-D schematically
illustrate an exemplary balloon catheter 1000 comprising a combined
infusion-guidewire lumen (referred to as infusion lumen 1114) with
selective valving mechanism 1300. Catheter 1000 includes a shaft
1100 having a length, a proximal end 1001 and a distal end 1002,
and a wall enclosing infusion lumen 1114 which is extending along
shaft's 1100 length and opened at both proximal end 1001 and distal
end 1002 with corresponding proximal opening 1112 and distal
opening 1118. Infusion lumen 1114 is further opened with a lateral
infusion opening 1116 (or optionally a number of openings) disposed
in shaft's 1100 wall between proximal end 1001 and distal end
1002.
[0045] An inflatable member 1200 is connected to shaft 1100
adjacent its distal end, distal to lateral infusion opening 1116.
An inflation lumen 1124, sealed to infusion lumen 1114, extends
between a proximal inflation opening 1122, at shaft's 1100 proximal
end, and a distal inflation port 1126, opened to an interior of
inflatable member 1200. Inflatable member 1200 may be a compliant
balloon, a semi-compliant balloon or a non-compliant balloon.
[0046] A valving mechanism according to the present disclosure may
be any type of controller, such as a mechanical device, for
selectively controlling a flow parameter of a fluid, for example a
flow rate. A valving mechanism may be set between two or more modes
that inhibit fluid flow by different amounts. In some cases, the
modes may include a fully closed mode in which flow is
substantially absent, and a fully opened valve in which fluid is
allowed to travel substantially unhindered by the valving
mechanism. Intermediate flow restrictions are also possible.
According to some preferred embodiments of the present disclosure,
a valving mechanism includes an elongated member such as a wire
(e.g., a guide wire) operational to selectively pass through or
withdraw from an infusion lumen portion sized and shaped
substantially the same as external boundaries of a correlating
portion thereof, being substantially narrowed as compared to a
proximal portion of the infusion lumen located between a fluid
inlet and a fluid outlet, such that when the wire occupies the
narrowed infusion lumen portion then no flow or at least
substantially no flow will pass therethrough. When the obstructing
wire is fully withdrawn from the constricted or narrowed infusion
lumen portion, fluid can pass therethrough. In an optional
alternative embodiment, other valving means may be applied so that
no fluid may pass through the narrowed infusion lumen portion also
when the obstructing wire is absent, so that all or at least
substantially all fluid will be delivered through a fluid outlet
that is positioned proximal to the narrowed infusion lumen
portion.
[0047] As shown in FIG. 1, guidewire-based valving mechanism 1300
may be provided in infusion lumen 1114 distal to lateral infusion
opening 1116. Valving mechanism 1300 is selectively operable to
block distal opening 1118 of infusion lumen 1114 such that fluid
passing distally through infusion lumen 1114 shall exit mainly or
solely through lateral infusion opening 1116 rather than through
distal opening 1118. In case that valving mechanism 1300 is set not
to block distal opening 1118, flow may pass via distal opening 1118
at all or in a greater rate.
[0048] As shown, infusion lumen 1114 defines a first segment 1320,
extending between proximal opening 1112 and a boundary 1340 (shown
adjacent to lateral infusion opening 1116 although it may be
further distal), and a second segment 1330, extending between
boundary 1340 and distal opening 1118. In some embodiments, in
first segment 1320, infusion lumen 1114 has a first minimal cross
section area, and in second segment 1330, infusion lumen 1114 has a
second minimal cross section area smaller than the first minimal
cross section than in first segment 1320. Valving mechanism 1300
includes an elongated member, preferably a guide wire 1310
selectively disposable in infusion lumen 1114 at first segment 1320
and/or second segment 1330. Guide wire 1310 is sized and configured
to pass through proximal opening 1112, infusion lumen 1114 and/or
distal opening 1118, and therefore allow an over-the-wire delivery
of catheter 1000 thereupon. Optionally and alternatively, catheter
1000 is configures for rapid exchange deliveries.
[0049] In some embodiments, the second minimal cross section is
sized and shaped such that guide wire 1310 can be selectively fit,
snugly, in the second minimal cross section in order to achieve
blocking of distal opening 1118 and/or second segment 1330 distal
to lateral infusion opening 1116. In some embodiments, the second
minimal cross section is circular whereas the first minimal cross
section is sized and shaped to virtually enclose a circle with
identical dimensions to said second minimal cross section (as shown
in the shape difference of infusion lumen 1114 in FIG. 1B vs. FIG.
1C). The first minimal cross section may be of any shape such as
circular, elliptic or crescent. FIGS. 4A-B schematically illustrate
cross sections of two other possible exemplary catheter portions
1000' and 1000'' which comprise combined infusion-guidewire lumens
1114' and 1114'', respectively. Both catheters 1000' and 1000'' are
over-the-wire type balloon catheters. In FIG. 4A, an inner wall
1125' dividing between infusion lumen 1114' and inflation lumen
1124' is partially curved to allow partial nesting with part of a
guide wire 1310' periphery in contact. Other part of guide wire
periphery not in contact with inner wall 1125' is opened at least
partially to infusion lumen 1114' interior so that fluid passing in
the lumen may contact it. FIG. 4B shows infusion lumen 1114'' and
inflation lumen 1124'' divided with a straight inner wall 1125'',
while guide wire 1310'' is mostly opened to infusion lumen 1114''
interior and may be only tangential to inner wall 1125''.
[0050] In an aspect of some embodiments, a method is disclosed for
operating a balloon catheter, such as balloon catheter 1000,
according to the present disclosure, comprising at least one of the
following steps (not necessarily in same order):
[0051] 1. inserting guidewire 1310 in a luminal vessel, such as a
vein or an artery, optionally a coronary, a peripheral or dialysis
target vessel;
[0052] 2. delivering balloon catheter 1000 in the luminal vessel
over guidewire 1310 to a chosen target;
[0053] 3. inflating inflatable member 1200 to occlude, at least
partially, the luminal vessel at the target;
[0054] 4. infusing a fluid (e.g., a liquid or suspended medicament
or contrast enhancing medium) through lateral infusion opening 1116
such that minimal or no fluid passes beyond inflatable member
1200.
[0055] In some embodiments, steps 3 and 4 are performed
simultaneously and/or in overlap. In some embodiments, guide wire
1310 is selectively occupying or withdrawn from second segment 1330
in infusion lumen 1114 according to need. In some embodiments,
catheter 1000 first engages guide wire 1310 by inserting it via
distal opening 1118, or alternatively, by inserting guide wire 1310
in infusion lumen 1114 via proximal opening 1112. In some
embodiments, the infusing occurs while the inflatable member is
filled and/or expanded, optionally fully or partially. Optionally,
the inflatable member is deflated after the infusing. In some
embodiments, the inflating generates a dilatation force in a
magnitude above a mechanical yield point of a stenotic blood vessel
wall. Optionally, alternatively or additionally, the mechanical
interaction between the filled and/or expanded inflatable member
with the blood vessel portion in contact creates a sealing thus
obstructing and/or diminishing substantially a fluid passing
therebetween.
[0056] In different exemplary embodiments, a valving mechanism may
include an additional valve or a seal for sealing around a guide
wire passing therethrough, and/or selectively seal an opening or a
segment of an infusion lumen when the guide wire is removed or
otherwise absent. In some embodiments, a catheter includes at least
one one-way valve allowing a guide wire passing therethrough while
sealing fluid passage. Optionally, the one-way valve is disposed
adjacent to catheter's distal end and/or between a distal opening
and a lateral infusion opening in the infusion lumen. Optionally,
alternatively or additionally, the one-way valve is disposed
adjacent to catheter's proximal end and/or between a proximal
opening and a lateral infusion opening in the infusion lumen.
Optionally, the catheter and/or the valving mechanism includes a
septum seal.
[0057] FIGS. 2A-B schematically illustrate portions in cross
section of an exemplary balloon catheter 2000 and seals provided
therein. Optionally and alternatively, only one seal of FIG. 2A or
FIG. 2B is provided therein. FIG. 2A shows a proximal portion of
balloon catheter 2000, comprising a wall 2100 enclosing an infusion
lumen 2114 openable at proximal infusion inlet or port 2112 to an
infusion fluid source (not shown), as well as an inflation lumen
(not shown) openable to proximal inflation port 2122. As shown, a
guide wire 2310 is passable through infusion lumen 2114 and
proximal infusion port 2112 and therefore a proximal valving
mechanism 2400 is required to avoid backflow via proximal infusion
port 2112. In some embodiments, proximal valving mechanism 2400
includes a proximal seal 2410 in the form of a "wire seal" adapted
to maintain sealing around periphery of guide wire 2310, if present
as shown. As such, proximal seal 2410 may include a plurality of
overlapping seal segments adapted to extend or narrow against outer
periphery of the guide wire while maintaining sealing. In some
embodiments, proximal valving mechanism 2400 may also include a
zero seal (which is "normally sealing"), in addition to the wire
seal, not shown, adapted to seal fluid backflow through proximal
infusion valve port 2112 when a wire is absent.
[0058] FIG. 2B shows a distal portion of balloon catheter 2000 in
which an inflatable member (balloon 2200) is fixated thereto.
Infusion lumen 2114 is opened to outer environment with a lateral
infusion opening 2116. Distally to lateral infusion opening 2116 in
infusion lumen 2114 there is provided a proximal valving mechanism
2300 comprising a septum seal 2320, optionally made of a highly
elastic and/or a viscoelastic material, allowing distal sealing
either if guide wire 2310 is absent (not shown) or passes
therethrough (as shown).
[0059] FIGS. 3A-B schematically illustrate portions in cross
section of a different exemplary balloon catheter 3000 and optional
exemplary seals provided therein. Balloon catheter 3000 includes a
wall 3100 enclosing an infusion lumen 3114 openable at a proximal
infusion inlet port 3112 to an infusion fluid source (not shown),
as well as an inflation lumen (not shown) openable to proximal
inflation port 3122. An inflatable member (balloon 3200) is fixated
at distal portion of catheter 3000. As shown, guide wire 3310 is
passable through infusion lumen 3114 however it does not pass
through proximal infusion port 3112 but rather through a dedicated
guide wire port 3130. Therefore a proximal valving mechanism 3400
comprising an O-ring or a septum seal 3410, is used in guide wire
port 3130 in order to avoid backflow of infusion fluid
therethrough. In the distal portion of balloon catheter 3000, as
shown in FIG. 3B, infusion lumen 3114 is shown opened to outer
environment with a lateral infusion outlet or opening 3116.
Distally to lateral infusion opening 3116 in infusion lumen 3114
there is provided a distal valving mechanism 3300 comprising a
normally closed seal 3320 adapted to maintain sealing therethrough
to infusion fluids either if guide wire 3310 passes therethrough or
is absent. In some embodiment, seal 3320 is an inflatable doughnut
shaped, optionally continuously pressurized, so that it maintains a
minimal sized core opening changeable from zero (when guide wire
3310 is absent) to outer diameter of guidewire 3310 if it passes
therethrough.
[0060] In some embodiments, balloon catheter 3000 ends distally
with a soft, elastic and/or pliable descending conic member 3118
which is normally tapered with a distal inner diameter
substantially smaller than its proximal inner diameter at least at
non-stressed and/or non-stretched form. If stretched out, for
example in case a guide wire passes therethrough and having
dimensions greater than those imposed by the non-stretched conic
member 3118, it maintains a sealed distal end around outer
boundaries of conic member 3118. Such sealing function may achieve
at least one of: blocking fluid therethrough from infusion lumen to
our environment of any infusion fluid such as saline or medicament,
and/or blocking fluid travel therethrough from outer environment
and into infusion lumen of body fluid such as blood. In some
embodiments, conic member 3118 is designed, sized and/or configured
such that guide wires having outer diameters between 0.01'' to
0.2'', optionally 0.018'' to 0.035'' or higher or lower or
intermediate, are unhinderly passable therethrough, and optionally
also stretching it at least partially to a radially extended form.
In some embodiments, conic member 3118 is normally sealed so that
in absence of any wire extending therethrough it is fully
compressed and sealed to fluids, at least at its distal-most
portion.
[0061] Reference is made to FIGS. 5A-H which schematically
illustrate cross sections in portions of different exemplary
catheters, in accordance with embodiments of the present invention.
All these cross sections represent portions of corresponding
infusion lumens, each extending between a distal fluid inlet and a
proximal fluid outlet. FIG. 5A shows a portion 3510 having a
circular cross section with a wall 3511 enclosing a first infusion
lumen 3512 with a dedicated area 3513 for partial nesting of a
guidewire (not shown) shaped to enclose most of guidewire's
periphery, and a second inflation lumen 3514. Optionally, portion
3510 is of a 5.5 French (F) PTA catheter whereas infusion lumen
3512 area is about 1.2 mm2 and inflation lumen 3514 area is about
0.34 mm2. FIG. 5B shows a portion 3520 having a circular cross
section with a wall 3521 enclosing a first infusion lumen 3522 with
a dedicated area 3523 for partial nesting of a guidewire (not
shown) shaped to enclose approximately half of guidewire's
periphery, and a second inflation lumen 3524. Optionally, portion
3520 is of a 5.5 F PTA catheter whereas infusion lumen 3522 area is
about 1.28 mm2 and inflation lumen 3524 area is about 0.31 mm2.
FIG. 5C shows a portion 3530 having a circular cross section with a
wall 3531 enclosing a first infusion lumen 3532 with a dedicated
area 3533 for partial nesting of a guidewire (not shown) shaped to
enclose most of guidewire's periphery, and a second inflation lumen
3534. Optionally, portion 3530 is of a 5 F occlusion balloon
catheter whereas infusion lumen 3532 area is about 0.82 mm2 and
inflation lumen 3514 area is about 0.54 mm2. FIG. 5D shows a
portion 3540 having a circular cross section with a wall 3541
enclosing a first infusion lumen 3542 with a dedicated area 3543
for partial nesting of a guidewire (not shown) shaped to enclose
approximately half of guidewire's periphery, and a second inflation
lumen 3544. Optionally, portion 3540 is of a 6 F PTA catheter
whereas infusion lumen 3542 area is about 1.52 mm2 and inflation
lumen 3444 area is about 0.5 mm2. FIG. 5E shows a portion 3550
having a circular cross section with a wall 3551 enclosing a first
infusion lumen 3552 with a dedicated area 3553 for partial nesting
of a guidewire (not shown) shaped to enclose most of guidewire's
periphery, and a second inflation lumen 3554. Optionally, portion
3550 is of a 5 F occlusion balloon catheter whereas infusion lumen
3552 area is about 1.09 mm2 and inflation lumen 3554 area is about
0.27 mm2. FIG. 5F shows a portion 3560 having a circular cross
section with a wall 3561 enclosing a first infusion lumen 3562 with
a dedicated area 3563 for partial nesting of a guidewire (not
shown) shaped to enclose most of guidewire's periphery, and a
second inflation lumen 3564. Optionally, portion 3560 is of a 6 F
PTA catheter whereas infusion lumen 3562 area is about 1.48 mm2 and
inflation lumen 3564 area is about 0.69 mm2. FIG. 5G shows a
portion 3570 having a circular cross section with a wall 3571
enclosing a first infusion lumen 3572, a second guidewire lumen
3573 and a third inflation lumen 3574. Optionally, portion 3570 is
of a 5.5 F PTA catheter whereas infusion lumen 3572 area is about
0.49 mm2, guidewire lumen 3573 area is about 0.69 mm2 and inflation
lumen 3574 area is about 0.35 mm2. FIG. 5H shows a portion 3580
having a circular cross section with a wall 3581 enclosing a first
infusion lumen 3582 with enough space yet without a dedicated area
for partial nesting of a guidewire (not shown), and a second
inflation lumen 3583. Optionally, portion 3580 is of a 5.5 F PTA
catheter whereas infusion lumen 3582 area is about 1.49 mm2 and
inflation lumen 3583 area is about 0.27 mm2.
[0062] Reference is now made to FIGS. 6A-B which schematically
illustrate an exemplary infusion lumen 110IL, as part of a
catheter, comprising a first exemplary valving mechanism, in
accordance with embodiments of the present invention. The catheter
includes an infusion wall 110 enclosing infusion lumen 110IL that
extends axially therealong. Infusion wall includes a proximal wall
segment 115, a distal wall segment 113 and an intermediate wall
segment 111 extending therebetween. Proximal wall segment 115
comprises a proximal guidewire opening 118 and distal wall segment
113 comprises a distal guidewire opening 119. A guidewire 120 is
shown extending through infusion lumen 110IL having its distal part
provided through distal guidewire opening 119 and its proximal part
provided through proximal guidewire opening 118. During treatment,
including catheter delivery, deployment or withdrawal, guidewire
120 may pass into infusion lumen 110IL through proximal guidewire
opening 118 or through distal guidewire opening 119.
[0063] Proximal wall segment 115 adjoins intermediate wall segment
111 with a widening 114, and intermediate wall segment 111 adjoins
distal wall segment 113 with a narrowing 112. Widening 114 and/or
narrowing 112 may be gradual or steep.
[0064] Intermediate wall segment 111 includes a fluid inlet 116
appositional to proximal wall segment 115 and a fluid outlet 117
appositional to distal wall segment 113.
[0065] Infusion lumen 110IL is shown during fluid dispersion when
fluid inlet 116 is located outside a patient body and fluid outlet
117 is located inside the patient body in a specific location in a
bodily lumen, optionally a blood vessel such as a vein or an
artery, optionally in apposition to a lesion or a stenosis. A fluid
inlet flow rate Fin travels in infusion lumen 110IL through fluid
inlet 116 while a fluid outlet flow 116 while a fluid outlet flow
rate Fout 1 travels out of infusion lumen 110IL to a target
location inside patient's body through fluid outlet 117.
[0066] In some embodiments, infusion lumen 110IL in distal wall
segment 113 is sized, shaped, and/or inner surface of distal wall
segment 113 is textured, such, to build a distal pressure gradient
allocating a distal flow rate Fout3 through distal guidewire
opening 119, being 40% or less fluid outlet flow rate Fout1 through
fluid outlet 117, optionally 20% or less, optionally 10% or less,
optionally 5% or less, optionally, 2% or less, or higher, or lower,
optionally null, or an intermediate percentage; optionally when
distal wall segment 113 is unobstructed, such as with guidewire
120, or optionally when distal wall segment 113 is obstructed with
guidewire 120.
[0067] In some embodiments, infusion lumen 110IL in proximal wall
segment 115 is sized, shaped, and/or inner surface of proximal wall
segment 115 is textured, such, to build a distal pressure gradient
allocating a negative flow rate Fout through proximal guidewire
opening 118, being 40% or less fluid outlet flow rate Fout 1
through fluid outlet 117, optionally 20% or less, optionally 10% or
less, optionally 5% or less, optionally, 2% or less, or higher, or
lower, optionally null, or an intermediate percentage; optionally
when proximal wall segment 115 is unobstructed, such as with
guidewire 120, or optionally when proximal wall segment 115 is
obstructed with guidewire 120.
[0068] Optionally, guidewire 120 is a 0.035'' guidewire, or a
0.025'' guidewire, or a 0.018'' guidewire, or a 0.014'' guidewire,
or lower, or higher, or intermediate in size.
[0069] Distal pressure gradient and/or proximal pressure gradient
is optionally determined according to an infusion fluid viscosity
of at least 0.65 centipoises ("cP"), or optionally of at least 3
cP, or optionally at least 6 cP, or optionally at least 8 cP;
considering that water viscosity at a temperature of 37.degree. C.
is approximately 0.69 cP, blood viscosity at same temperature is
approximately 3 to 4 cP, and iodine based contrast media is
commonly between approximately 4 cP to approximately 12 cP.
[0070] In some embodiments, a cross section area of fluid outlet
117 Dprx divided by a cross section area A of distal guidewire
opening 119 is at least 1.5, optionally at least 2, optionally at
least 3, optionally at least 5, optionally at least 10, or higher,
or lower, or an intermediate value. Optionally, a cross section
area Dgw of proximal guidewire opening 118 is equal to or less than
cross section area A distal guidewire opening 119.
[0071] Optionally, a cross section of infusion lumen 110IL in
distal wall segment 113 and/or in proximal wall segment 115 is
circular and 0.3 mm to 1.5 mm in diameter.
[0072] In some embodiments, proximal wall segment 115 and/or distal
wall segment 113 is at least 10 mm in length, optionally at least
20 mm, optionally at least 50 mm, optionally at least 100 mm, or
higher, or lower, or has an intermediate value.
[0073] In some embodiments, distal guidewire opening 119 and/or
proximal guidewire opening 118 is 0.3 mm to 2 mm in diameter,
optionally 0.5 mm to 1.5 mm, optionally 0.9 to 1 mm, or optionally
0.3 mm to 0.9 mm, or optionally about 0.95 mm.
[0074] Infusion lumen 110IL at intermediate wall segment 111 may
take any of a plurality of cross sections forms, as long as they
are sized and shaped to virtually enclose a circle with dimensions
equal or higher than to outer dimensions of guidewire 120 or a
thicker guidewire that can be used with the catheter. FIGS. 11A-C
schematically illustrate different exemplary cross section shapes
for of infusion lumen 110IL at intermediate wall segment 111, in
accordance with embodiments of the present invention. FIG. 11A
shows a circular cross section of intermediate wall segment 111
with internal diameter ID equal or greater than guidewire 120
diameter. FIG. 11B shows a cross section of infusion lumen 110IL at
intermediate wall segment 111 being noncircular shaped with a
smallest distance APL between antipodal points AP1 and AP2 at an
inner boundary thereof. FIG. 11C shows a cross section of infusion
lumen 110IL at intermediate wall segment 111 being crescent shaped
with a smallest distance ARL between two opposing arcs AR1 and AR2
at an inner boundary thereof. Optionally distance APL and/or ARL is
at least 0.3 mm, optionally at least 0.5 mm, optionally at least
0.9 mm, optionally at least 1.5 mm, optionally at least 3 mm, or
higher, or lower, or an intermediate value. In some embodiments,
the cross section area of infusion lumen 110IL at intermediate wall
segment 111, regardless of any chosen shape (as in FIGS. 11A-C or
otherwise) is at least 1 mm2, optionally 1.5 mm2, optionally at
least 1.75 mm2, optionally at least 2 mm2, optionally at least 4
mm2, or higher, or lower, or of any intermediate value.
[0075] Fluid outlet 117 may include any number of openings of any
form and size, and of any arrangement with any pattern. As such,
fluid outlet may include at least one hole (i.e. a through
opening), at least one slit and/or at least one pressure sensitive
opening. Optionally the at least one slit is configured to open
above a predetermined infusion pressure, optionally of at least 1
bar, optionally at least 2 bar, optionally at least 4 bar, or
higher, or lower, or intermediate. Optionally, there are at least 2
openings, optionally at least 4 openings, optionally at least 10
openings, optionally at least 50 openings, or higher, or lower, or
an intermediate number. In some embodiments, the overall area of
fluid outlet 117 is equal or higher than cross section area
(minimal or average, in case it is not constant) of infusion lumen
110IL at intermediate wall segment 111, optionally equal or higher
than 1.5 times its size, optionally equal or higher than 2 times
its size, optionally equal or higher than 5 times its size, or
higher, or lower, or an intermediate value. Optionally and
alternatively, the overall area of fluid outlet 117 is equal or
higher than cross section area of infusion lumen 110IL at
intermediate wall segment 111 less cross section area of guidewire
120. In some embodiments, fluid outlet 117 may include a number of
openings, optionally provided in form of series, optionally around
a periphery of the catheter and/or along a portion of its length.
At least one opening may be directly opposing an at least one
opening at an opposing wall portion of the catheter, and/or at
least one opening may be peripherally and/or longitudinally offset
to another at least one opening at a different wall portion of the
catheter. FIGS. 12A-C schematically illustrate different exemplary
fluid outlet types and/or distribution, in accordance with
embodiments of the present invention. FIG. 12A shows infusion lumen
110IL at intermediate wall segment 111 with a crescent cross
section and a single hole as fluid outlet 117. FIG. 12B shows
infusion lumen 110IL at intermediate wall segment 111 with a
crescent cross section and a number of holes as fluid outlet 117.
FIG. 12C shows infusion lumen 110IL at intermediate wall segment
111 with a crescent cross section and a single pressure sensitive
slit as fluid outlet 117.
[0076] In some embodiments the catheter also comprises an
inflatable member and an inflation wall enclosing an inflation
lumen with the infusion wall along a length thereof. The inflatable
member may be a dilatation balloon comprising a non-compliant or a
semi-compliant material, or it may be an occlusion balloon
comprising a compliant material. FIGS. 7A-B schematically
illustrate balloon catheter incorporating exemplary valving
mechanisms differentiated by balloon location relative to fluid
outlet, in accordance with embodiments of the present invention.
FIG. 7A shows a catheter 100 which includes infusion wall 110
enclosing infusion lumen 110IL, similar to as described above.
Catheter 100 also includes an inflatable member 136 and an
inflation wall 130 enclosing an inflation lumen 1301L with infusion
wall 110 along part of inflation lumen length. Inflation lumen
1301L includes an inflation inlet 132, optionally located in
relative opposition to proximal guidewire opening 118 and/or to
fluid inlet 116, as well as an inflation outlet 134 located within
the sealed inner boundary of inflatable member 136. Inflatable
member may be configured as a dilatation and/or occlusion balloon.
As shown, in this example, dilatation member 136 is provided in
between fluid outlet 117 and distal guidewire opening 119. This
will allow dispersion of fluid such as contrast enhancing media,
flushing fluid, dissolvent and/or medicament only proximal and
optionally adjacent to inflatable member 136.
[0077] FIG. 7B shows a catheter 140 which includes infusion wall
110 enclosing infusion lumen 110IL, similar to as described above.
Catheter 140 also includes an inflatable member 136 and an
inflation wall 130 enclosing an inflation lumen 1301L with infusion
wall 110 along part of inflation lumen length. Inflation lumen
1301L includes an inflation inlet 132, optionally located in
relative opposition to proximal guidewire opening 118 and/or to
fluid inlet 116, as well as an inflation outlet 134 located within
the sealed inner boundary of inflatable member 136. Inflatable
member may be configured as a dilatation and/or occlusion balloon.
As shown, in this example, fluid outlet 117 includes a
proximal-most opening 142 and a distal-most opening 144, wherein
inflatable member 136 extends therebetween. This will allow
dispersion of fluid such as contrast enhancing media, flushing
fluid, dissolvent and/or medicament proximally and distally, and
optionally adjacent, to inflatable member 136.
[0078] In some embodiments other valving or sealing means are
provided in addition to the guidewire based valving mechanism in
order to improve and/or offer different possibilities for
delivering fluids into a target bodily lumen. FIGS. 8A-B
schematically illustrate an exemplary infusion lumen 210IL, as part
of a catheter, comprising an exemplary valving mechanism with
additional backflow seal, in accordance with embodiments of the
present invention. The catheter includes an infusion wall 210
enclosing infusion lumen 210IL that extends axially therealong.
Infusion wall includes a proximal wall segment 215, a distal wall
segment 213 and an intermediate wall segment 211 extending
therebetween. Proximal wall segment 215 comprises a proximal
guidewire opening 218 and distal wall segment 213 comprises a
distal guidewire opening 219. A guidewire 220 is shown extending
through infusion lumen 210IL having its distal part provided
through distal guidewire opening 219 and its proximal part provided
through proximal guidewire opening 218. During treatment, including
catheter delivery, deployment or withdrawal, guidewire 220 may pass
into infusion lumen 210IL through proximal guidewire opening 218 or
through distal guidewire opening 219.
[0079] Proximal wall segment 215 adjoins intermediate wall segment
211 with a widening 214, and intermediate wall segment 211 adjoins
distal wall segment 213 with a narrowing 212. Widening 214 and/or
narrowing 212 may be gradual or steep.
[0080] Intermediate wall segment 211 includes a fluid inlet 216
appositional to proximal wall segment 215 and a fluid outlet 217
appositional to distal wall segment 213.
[0081] As shown, a guidewire seal 230 is provided in infusion lumen
210IL between fluid inlet 216 and proximal guidewire opening 218.
In some embodiments, guidewire seal 230 is an inflatable annular
seal which includes an annular inflatable body 231 having a lumen
232, and a seal inlet 234. In some embodiments, inflatable body 231
has an outer periphery, fixed to infusion wall 210, and an inner
periphery surrounding lumen 232 with a selectively changeable inner
diameter. In some embodiments, seal inlet 234 is provided adjacent
and in direct fluid communication with fluid inlet 216, optionally
dividing an intake passage at fluid inlet 216 to seal inlet 234 and
to an infusion inlet 233, so that when fluid is forced through
fluid inlet 216 it will be divided between filling infusion lumen
210IL and fluid delivery through fluid outlet 217, and inflating
guidewire seal 230 such that its lumen 232 decreases in diameter
down to a minimal degree. In some embodiments, guidewire seal 230
may decrease in inner diameter below to a predetermined guidewire
diameter. When guidewire seal 230 is deflated its lumen 232 is
relatively enlarged so that guidewire 220 can travel freely
therethrough (as shown in FIG. 8A) whereas when it is inflated to a
certain degree, optionally up to a maximal inflation volume, lumen
232 decreases in diameter to equal or less than guidewire 220 outer
boundaries (as shown in FIG. 8B) therefore sealing a fluid passage
therebetween. In some embodiments, inflatable body 231 includes a
compliant material capable of conforming to guidewire boundaries at
certain inner pressures.
[0082] FIGS. 9A-B schematically illustrate an exemplary infusion
lumen 310IL, as part of a catheter, comprising an exemplary valving
mechanism with additional exemplary proximal and distal sealing
sets, in accordance with embodiments of the present invention. The
catheter includes an infusion wall 310 enclosing infusion lumen
310IL that extends axially therealong. Infusion wall includes a
proximal wall segment 315, a distal wall segment 313 and an
intermediate wall segment 311 extending therebetween. Proximal wall
segment 315 comprises a proximal guidewire opening 318 and distal
wall segment 313 comprises a distal guidewire opening 319. A
guidewire 320 is shown extending through infusion lumen 310IL
having its distal part provided through distal guidewire opening
319 and its proximal part provided through proximal guidewire
opening 318. During treatment, including catheter delivery,
deployment or withdrawal, guidewire 320 may pass into infusion
lumen 310IL through proximal guidewire opening 318 or through
distal guidewire opening 319.
[0083] Proximal wall segment 315 adjoins intermediate wall segment
311 with a widening 314, and intermediate wall segment 311 adjoins
distal wall segment 213 with a narrowing 312. Widening 314 and/or
narrowing 312 may be gradual or steep.
[0084] Intermediate wall segment 311 includes a fluid inlet 316
appositional to proximal wall segment 315 and a fluid outlet 317
appositional to distal wall segment 313.
[0085] As shown, a proximal guidewire seal 330 is provided in
infusion lumen 310IL between fluid inlet 316 and proximal guidewire
opening 318. In some embodiments, proximal guidewire seal 330 is an
inflatable annular seal which includes an annular inflatable body
331 having a lumen 332, and a seal inlet 334. In some embodiments,
inflatable body 331 has an outer periphery, fixed to infusion wall
310, and an inner periphery surrounding lumen 332 with a
selectively changeable inner diameter. In some embodiments, seal
inlet 334 is provided adjacent and in direct fluid communication
with fluid inlet 316, optionally dividing an intake passage at
fluid inlet 316 to seal inlet 334 and to an infusion inlet 333, so
that when fluid is forced through fluid inlet 316 it will be
divided between filling infusion lumen 310IL and fluid delivery
through fluid outlet 317, and inflating proximal guidewire seal 330
such that its lumen 332 decreases in diameter down to a minimal
degree.
[0086] A distal guidewire seal 340 is also provided in infusion
lumen 310IL between fluid outlet 317 and distal guidewire opening
319. In some embodiments, distal guidewire seal 340 is an
inflatable annular seal which includes an annular inflatable body
341 having a lumen 342, and a seal inlet 344. In some embodiments,
inflatable body 341 has an outer periphery, fixed to infusion wall
310, and an inner periphery surrounding lumen 342 with a
selectively changeable inner diameter. In some embodiments, seal
inlet 334 is provided in infusion lumen 310IL so that when pressure
arises therein, fluid is forced through fluid outlet 317 in
parallel or after to inflating distal guidewire seal 340 such that
its lumen 342 decreases in diameter down to a minimal degree.
[0087] In some embodiments, proximal guidewire seal 330 and distal
guidewire seal 340 may decrease in inner diameter below to a
predetermined guidewire diameter. When guidewire seals 330 and 340
deflates, their lumens 332 and 342, respectively, are relatively
enlarged so that guidewire 320 can travel freely therethrough
whereas when they are inflated to a certain degree, optionally up
to a maximal inflation volume, lumens 332 and 342 decrease in
diameter to equal or less than guidewire 320 outer boundaries (as
shown in FIG. 9B) therefore sealing a fluid passage therebetween.
In some embodiments, inflatable bodies 331 and 341 include
compliant material capable of conforming to guidewire boundaries at
certain inner pressures.
[0088] In some embodiments, a proximal zero seal 352 is provided
between fluid inlet 316 and proximal guidewire opening 318.
Optionally and additionally, a distal zero seal 354 is provided
between fluid outlet 317 and distal guidewire opening 319. Zero
seals 352 and 354 are normally closed to fluid flow at the absence
of a guidewire passing therethrough. FIG. 9A shows a scenario in
which a guidewire is absent from infusion lumen 310IL yet by
delivering a fluid Fin therein through fluid inlet 316 a fluid Fout
is delivered out only through fluid outlet 317 and not through
guidewire openings 318 and 319 since that zero seals 352 and 354
are closed and sealed to fluid passage therethrough. FIG. 9B shows
another scenario in which guidewire 320 travels through infusion
lumen 310IL and guidewire openings 318 and 319, forcing zero seals
352 and 354 to open, yet by delivering a fluid Fin in infusion
lumen 310IL it can only be delivered (as fluid Fout) through fluid
outlet 317 since that both guidewire seals are inflated and seal
fluid passage between them and guidewire 320.
[0089] Reference is now made to FIGS. 10A-I which illustrate side
views and cross section views of an exemplary angioplasty infusion
balloon catheter 400 comprising a guidewire based valving
mechanism, in accordance with embodiments of the present invention.
Balloon catheter 400 includes an elongated shaft 410 connected at
its proximal end with a triple connector 420. An inflatable
angioplasty balloon 430 is provided along a portion of its distal
end. Shaft 410 encloses an infusion lumen 414 and an inflation
lumen 415 separated and sealed to infusion lumen 414 with a wall
413. Infusion lumen 414 extends along entire length and opened at
both ends of catheter 400, having a proximal guidewire opening 422
and a distal guidewire opening 424, allowing in size and shape
passage in between and therethrough of a guidewire 440. Infusion
lumen 414 also includes a fluid inlet 421 in triple connector 420
distally to proximal guidewire opening 422. Fluid inlet 421
comprises a single opening and connection means (optionally a luer
connection to a syringe) for allowing selective introduction into
infusion lumen 414 of at least type of fluid, such as a contrast
enhancing medium, flushing fluid (e.g., saline), medicament,
chemical or biological compounds, or others. A fluid outlet 412 is
provided proximally and close (optionally adjacent) to balloon 430
and allows delivery of fluid outside infusion lumen 414 proximally
and adjacent to balloon 430. Fluid outlet 412 may include a single
opening (as shown) or a plurality of openings of any chosen number,
form, arrangement or other.
[0090] Inflation lumen 415 extends about most of infusion lumen 414
length, between an inflation inlet 423 in triple connector 420,
distally to proximal guidewire opening 422 and in general opposite
direction to fluid inlet 421, and an inflation outlet opened to
inner volume of balloon 430. Inflation inlet 423 comprises a single
opening and connection means (optionally a luer connection to a
syringe) for allowing selective delivery into or withdrawal from
inflation lumen 415 of inflation fluid (optionally saline,
optionally with contrast enhancing agent) for inflating and
deflating, respectively, balloon 430.
[0091] Infusion lumen 414 includes a proximal segment 409 extending
at least partially between proximal guidewire opening 422 and fluid
inlet 421, a distal segment 418 extending at least partially
between fluid outlet 412 and distal guidewire opening 424, and an
intermediate segment extending in between proximal segment 409 and
distal segment 418. Proximal segment 409 and distal segment 418
have circular cross sections equal or slightly over cross section
of guidewire 440 so that the guidewire can snugly fit therein yet
can be passed freely either proximally or distally. The
intermediate segment of infusion lumen 414 has a crescent shaped
cross section which encloses a circular area equal or greater than
cross section area of guidewire 440. This way, a fluid can travel
freely in infusion lumen 414 intermediate segment from fluid inlet
421 to fluid outlet 412 despite presence of guidewire 440. Proximal
segment 409 adjoins the intermediate segment with a gradual
widening 419 and the intermediate segment adjoins distal segment
418 with a gradual narrowing 417. The close fit of guidewire 440 in
proximal segment 409 and distal segment 418 of infusion lumen 414
and substantial lengths thereof (greater than 20 mm, optionally
about 50 mm, each) seals (fully or partially) fluid travel
therethrough, so that most or all infusion fluid entering infusion
lumen 414 through fluid inlet 421 will be delivered through fluid
outlet 412 and not through proximal guidewire opening 422 and
distal guidewire opening 424, at least as long as guidewire 440
nests therein and obstructs them.
[0092] Balloon 430 includes a non-compliant or semi-compliant
inflatable membrane 431 fixated in both ends to shaft 410 outer
periphery with a proximal constriction 432 and a distal
constriction 433. An optional soft tip 434 is provided for
improving safety to vasculature during delivery. Balloon 430 is
configured for dilating a narrowed portion, optionally stenotic, of
a blood vessel by inflating it under a moderate to high pressure,
according to anatomic location and blood vessel diameter at the
treatment location. Inflation lumen 415 being completely sealed to
infusion lumen 414 allows an independent applicability of balloon
430 with respect to infusion and fluid delivery through fluid
outlet 412, so that fluid can be delivered if balloon 430 is
inflated, deflated or while being in a process of inflation or
deflation. Delivering contrast media, agent or medicament
proximally to balloon 430 when inflated has some advantages as
balloon 430 acts also as an occlusion balloon enabling this way a
localized delivery and treatment instead of systemic.
[0093] In some embodiments of the present invention, a fluid outlet
of a dilatation balloon catheter has a single, substantially large
opening. In some embodiments, the total opened area of the opening
is equal to or greater than a minimal cross section area of the
infusion lumen, in a portion proximal to the opening. Optionally
and alternatively, the total opened area is equal or greater than a
minimal cross section area of the infusion lumen, in a portion
proximal to the opening less a cross section area of a guidewire of
a minimally allowed diameter, or of a maximally allowed diameter,
or an intermediate value. In some embodiments, total opened area of
fluid outlet is at least 0.5 mm2, optionally at least 1 mm2,
optionally at least 2 mm2, optionally at least 5 mm2, optionally
about 1.2 mm2, optionally about 2.5 mm2 or higher, or lower, or an
intermediate value. One advantage of a substantially large single
opening, rather than a plurality of smaller openings, is the
possibility to inject fluids in equal or greater rates without
causing jets from the fluid outlet. In some embodiments, in order
to prevent a possible deformation (e.g., a kinking, a bending, a
twisting, or a combination thereof, or other) and/or deterioration
the catheter shaft adjacent the opening, due to the possible
increased weakening made by a substantially large single opening, a
structural fortification is added to the catheter shaft about the
opening. FIGS. 13, 14 and 15 disclose three exemplary types of
fortifications.
[0094] The device illustrated in FIGS. 10A-10I is made according to
the principles illustrated schematically in FIG. 7A. As noted
above, it is advantageous for the lengths of the narrowed portions
of the infusion lumen at the proximal and distal portions of the
catheter (designated 113 and 115 in FIG. 7A) to be 20 mm long or
more, and also for the infusion opening positioned proximal to the
balloon (designated 117 in FIG. 7A) to be a single opening having a
cross sectional area equal to or greater than the minimal cross
sectional area of the infusion lumen in between the narrowed
portions minus the cross sectional area of the largest diameter
allowed guidewire. The cross sectional area of the largest diameter
allowed guidewire is approximately equal to the cross sectional
area of at least the distal narrowed portion of the infusion lumen.
The cross sectional area of the infusion opening can thus be
expressed as equal to or greater than the minimal cross sectional
area of the larger cross section portion of the infusion lumen
between the narrowed portions (designated 111 in FIG. 7A), and the
minimal cross sectional area of the distal narrowed portion of the
infusion lumen. This implementation has the significant advantage
that the relatively long lengths of the narrowed portions of the
infusion lumen substantially seal the ends of the infusion lumen in
the presence of the guidewire without the use of additional valving
or clamping structures that complicate device construction, and the
relatively large infusion opening provides a high volume outflow of
infusate. This remains true even when the nesting of the guidewire
in the narrowed portions of the infusion lumen is loose enough to
allow easy sliding of the catheter structure over the
guidewire.
[0095] FIGS. 13A-B schematically illustrate cut views of an
exemplary balloon catheter 500 with a single proximal fluid outlet
512 comprising a first exemplary fortification, in accordance with
embodiments of the present invention. Balloon catheter 500 shown
with its distal end includes an elongated shaft 510 and an
inflatable angioplasty balloon 530 that is provided along a portion
of its distal end. Shaft 510 encloses an infusion lumen 514 and an
inflation lumen 515 separated and sealed to infusion lumen 514 with
a wall 513. Inflation lumen 515 being completely sealed to infusion
lumen 514 allows an independent applicability of balloon 530, so
that fluid can be delivered if balloon 530 is inflated, deflated or
while being in a process of inflation or deflation.
[0096] Infusion lumen 514 includes a distal guidewire opening 524
allowing passage therethrough of a guidewire (not shown) optionally
one of several possibly prescribed guidewires. A fluid outlet 512
is provided proximally and close (optionally adjacent) to balloon
530 and allows delivery of fluid outside infusion lumen 514
proximally and adjacent to balloon 530. Infusion lumen 514 narrows
with a gradual narrowing 517 into a distal segment 518. Until
narrowing 517, infusion lumen 514 has a crescent shaped cross
section which encloses a circular area equal or greater than cross
section area of a guidewire with a maximally allowed diameter.
Distal segment 518 has circular cross sections equal or slightly
over cross section of said guidewire so that the guidewire can
snugly fit therein yet can be passed freely either proximally or
distally. Infusion lumen 514 is configured such that most or all
infusion fluid entering therein will be delivered through fluid
outlet 512 and not through distal guidewire opening 524, at least
as long a prescribed guidewire nests therein and obstructs distal
segment 518 and distal guidewire opening 524.
[0097] Fluid outlet 512 has a single, substantially large opening
with a total opened area being equal to or greater than the cross
section area of infusion lumen 514 proximal to fluid outlet 512
less a cross section area of a guidewire with a minimal prescribed
diameter. The portion of shaft 510 about fluid outlet 512 is
fortified with a mesh patch 545 optionally made from stainless
steel in a rectangular shape curved to nest over shaft 510. In some
embodiments, the total opened area of fluid outlet 512 is
calculated as the total area covered by the outline of fluid outlet
512 less the area covered by mesh 545 above fluid outlet 512. Mesh
patch 545 is fixated to shaft 510 with a cover such as a flexible
sleeve 540, optionally made from nylon, with a hole cut thereto
enclosing fluid outlet 512. Therefore, fluid delivered through
fluid outlet 512 will pass then through the portion of mesh insert
545 thereabove and then through the hole in sleeve 540.
[0098] FIGS. 14A-B schematically illustrate cut views of an
exemplary balloon catheter 600 with a single proximal fluid outlet
612 comprising a second exemplary fortification, in accordance with
embodiments of the present invention. Balloon catheter 600 shown
with its distal end includes an elongated shaft 610 and an
inflatable angioplasty balloon 630 that is provided along a portion
of its distal end. Shaft 610 encloses an infusion lumen 614 and an
inflation lumen 615 separated and sealed to infusion lumen 614 with
a wall 613. Inflation lumen 615 being completely sealed to infusion
lumen 614 allows an independent applicability of balloon 630, so
that fluid can be delivered if balloon 630 is inflated, deflated or
while being in a process of inflation or deflation.
[0099] Infusion lumen 614 includes a distal guidewire opening 624
allowing passage therethrough of a guidewire (not shown) optionally
one of several possibly prescribed guidewires. A fluid outlet 612
is provided proximally and close (optionally adjacent) to balloon
630 and allows delivery of fluid outside infusion lumen 614
proximally and adjacent to balloon 630. Infusion lumen 614 narrows
with a gradual narrowing 617 into a distal segment 618. Until
narrowing 617, infusion lumen 614 has a crescent shaped cross
section which encloses a circular area equal or greater than cross
section area of a guidewire with a maximally allowed diameter.
Distal segment 618 has circular cross sections equal or slightly
over cross section of said guidewire so that the guidewire can
snugly fit therein yet can be passed freely either proximally or
distally. Infusion lumen 614 is configured such that most or all
infusion fluid entering therein will be delivered through fluid
outlet 612 and not through distal guidewire opening 624, at least
as long a prescribed guidewire nests therein and obstructs distal
segment 618 and distal guidewire opening 624.
[0100] Fluid outlet 612 has a single, substantially large opening
with a total opened area being equal to or greater than the cross
section area of infusion lumen 614 proximal to fluid outlet 612
less a cross section area of a guidewire with a minimal prescribed
diameter. The portion of shaft 610 about fluid outlet 612 is
fortified with a tube insert 640 optionally made from stainless
steel and having an internal diameter equal or greater than a
maximally allowed guidewire diameter, and an outer diameter equal
or smaller than a circle enclosed in infusion lumen 614 between
wall 613 and shaft 610. Tube insert 640 is fixated to shaft 610
optionally by soldering or gluing, or it may be freely disposed
therein, optionally in a snug fit. Tube insert 640 includes a hole
positioned such to enclose fluid outlet 612. Therefore, fluid
delivered through fluid outlet 612 will pass first through the hole
in tube insert 640.
[0101] FIGS. 15A-B schematically illustrate cut views of an
exemplary balloon catheter 700 with a single proximal fluid outlet
712 comprising a third exemplary fortification, in accordance with
embodiments of the present invention. Balloon catheter 700 shown
with its distal end includes an elongated shaft 710 and an
inflatable angioplasty balloon 730 that is provided along a portion
of its distal end. Shaft 710 encloses an infusion lumen 714 and an
inflation lumen 715 separated and sealed to infusion lumen 714 with
a wall 713. Inflation lumen 715 being completely sealed to infusion
lumen 714 allows an independent applicability of balloon 730, so
that fluid can be delivered if balloon 730 is inflated, deflated or
while being in a process of inflation or deflation.
[0102] Infusion lumen 714 includes a distal guidewire opening 724
allowing passage therethrough of a guidewire (not shown) optionally
one of several possibly prescribed guidewires. A fluid outlet 712
is provided proximally and close (optionally adjacent) to balloon
730 and allows delivery of fluid outside infusion lumen 714
proximally and adjacent to balloon 730. Infusion lumen 714 narrows
with a gradual narrowing 717 into a distal segment 718. Until
narrowing 717, infusion lumen 714 has a crescent shaped cross
section which encloses a circular area equal or greater than cross
section area of a guidewire with a maximally allowed diameter.
Distal segment 718 has circular cross sections equal or slightly
over cross section of said guidewire so that the guidewire can
snugly fit therein yet can be passed freely either proximally or
distally. Infusion lumen 714 is configured such that most or all
infusion fluid entering therein will be delivered through fluid
outlet 712 and not through distal guidewire opening 724, at least
as long a prescribed guidewire nests therein and obstructs distal
segment 718 and distal guidewire opening 724.
[0103] Fluid outlet 712 has a single, substantially large opening
with a total opened area being equal to or greater than the cross
section area of infusion lumen 714 proximal to fluid outlet 712
less a cross section area of a guidewire with a minimal prescribed
diameter. The portion of shaft 710 about fluid outlet 712 is
fortified with a sheet insert 740 optionally made from stainless
steel in a rectangular shape curved to nest in shaft 710. Sheet
insert 740 is fixated to shaft 710 optionally by soldering or
gluing, or optionally the fortified portion and/or sheet insert 740
is deformed resulting in a tight fit. Tube insert 740 includes a
hole positioned such to enclose fluid outlet 712. Therefore, fluid
delivered through fluid outlet 712 will pass first through the hole
in tube insert 740.
[0104] The following table show exemplary not binding parameters
for dilatation balloon catheter according to the present invention,
separated according to indication (i.e., a specific anatomic
location and/or blood vessel type in need for dilatation and/or
revascularization).
TABLE-US-00001 TABLE 1 Exemplary sizes and indications of balloon
catheters Balloon Dilatation diameter Catheter Sheath pressures:
Guidewire and length length size nominal and size Indication (mm)
(cm) (F) RPB (Atm) (Inches) PTA catheter for D: 5-12 50/80/135
6/7/8 Nom.: 8 0.035 treating AV L: 20/40/60/80 RPB: 18-30 fistula
or graft PTA catheter for D: 14-18 80/120 8 Nom.: 8 0.035 treating
large L: 20/40/60 RPB: 10-12 blood vessels PTA catheter for D: 4-9
80/135 5-8 Nom.: 6-8 0.018/0.035 treating peripheral L: 20-200 RPB:
10-15 blood vessels PTA catheter for D: 1.5-4 140 5 Nom.: 6 0.014
treating coronary L: 8-40 RPB: 14 blood vessels Embolectomy D: 4-15
40/80 4-8 0.025/0.035 catheter
[0105] It is to be fully understood that certain aspects,
characteristics, and features, of the invention, which are, for
clarity, illustratively described and presented in the context or
format of a plurality of separate embodiments, may also be
illustratively described and presented in any suitable combination
or sub-combination in the context or format of a single embodiment.
Conversely, various aspects, characteristics, and features, of the
invention which are illustratively described and presented in
combination or sub-combination in the context or format of a single
embodiment, may also be illustratively described and presented in
the context or format of a plurality of separate embodiments.
[0106] Although the invention has been illustratively described and
presented by way of specific exemplary embodiments, and examples
thereof, it is evident that many alternatives, modifications,
or/and variations, thereof, will be apparent to those skilled in
the art. Accordingly, it is intended that all such alternatives,
modifications, or/and variations, are encompassed by the broad
scope of the appended claims.
[0107] All publications, patents, and or/and patent applications,
cited or referred to in this disclosure are herein incorporated in
their entirety by reference into the specification, to the same
extent as if each individual publication, patent, or/and patent
application, was specifically and individually indicated to be
incorporated herein by reference. In addition, citation or
identification of any reference in this specification shall not be
construed or understood as an admission that such reference
represents or corresponds to prior art of the present invention. To
the extent that section headings are used, they should not be
construed as necessarily limiting.
* * * * *