U.S. patent application number 13/467679 was filed with the patent office on 2013-11-14 for catheter having dual balloon hydraulic actuator.
The applicant listed for this patent is Michael R Bialas, Michael L. Green. Invention is credited to Michael R Bialas, Michael L. Green.
Application Number | 20130304180 13/467679 |
Document ID | / |
Family ID | 49549245 |
Filed Date | 2013-11-14 |
United States Patent
Application |
20130304180 |
Kind Code |
A1 |
Green; Michael L. ; et
al. |
November 14, 2013 |
CATHETER HAVING DUAL BALLOON HYDRAULIC ACTUATOR
Abstract
Catheter comprising an inner tubular member defining a fluid
lumen and inflation lumen therein. An exterior surface of the inner
tubular member defines a fluid flow port in fluid communication
with the fluid lumen and located along a region of the inner
tubular member. Catheter further includes an outer member having a
distal section movable relative to the inner tubular member and
having an interior surface. A piston balloon is coupled to the
inner tubular member distal to the fluid flow port and is in fluid
communication with the inflation lumen. A pressure chamber is in
fluid communication with the fluid flow port. Fluid introduced
through the inflation lumen inflates the piston balloon to seal
against the interior surface and fluid introduced through the fluid
flow port and into the pressure chamber applies a force to urge at
least the distal section of the outer member in a proximal
direction.
Inventors: |
Green; Michael L.;
(Pleasanton, CA) ; Bialas; Michael R; (Wildomar,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Green; Michael L.
Bialas; Michael R |
Pleasanton
Wildomar |
CA
CA |
US
US |
|
|
Family ID: |
49549245 |
Appl. No.: |
13/467679 |
Filed: |
May 9, 2012 |
Current U.S.
Class: |
623/1.11 ;
604/103.04; 604/103.09; 604/96.01; 604/99.01; 604/99.04 |
Current CPC
Class: |
A61M 25/09 20130101;
A61M 2025/1079 20130101; A61M 2025/1081 20130101; A61F 2/958
20130101; A61M 25/10182 20131105; A61F 2/9522 20200501; A61M
2025/0079 20130101; A61F 2/966 20130101; A61M 2025/0183 20130101;
A61M 25/10185 20131105 |
Class at
Publication: |
623/1.11 ;
604/96.01; 604/103.09; 604/103.04; 604/99.01; 604/99.04 |
International
Class: |
A61F 2/84 20060101
A61F002/84; A61M 25/10 20060101 A61M025/10 |
Claims
1. A catheter comprising: an inner tubular member having a length
and an exterior surface, the inner tubular member defining a fluid
lumen and an inflation lumen therein, the exterior surface defining
a fluid flow port in fluid communication with the fluid lumen and
located along a region of the inner tubular member; an outer member
having a distal section movable relative to the inner tubular
member, the outer member having an interior surface facing the
exterior surface of the inner tubular member; a piston balloon
coupled to the inner tubular member distal to the fluid flow port
and in fluid communication with the inflation lumen, the piston
balloon disposed between the inner tubular member and the outer
member, the piston balloon having a deflated condition and an
inflated condition, wherein the piston balloon in the inflated
condition sealingly engages with the interior surface of the outer
tubular member; a proximal seal located proximal to the distal
section and proximal to the fluid flow port; and a pressure chamber
defined by the proximal seal, the piston balloon in the inflated
position, the exterior surface of the inner tubular member, and the
interior surface of outer member, the pressure chamber being in
fluid communication with the fluid flow port; wherein fluid
introduced through the inflation lumen inflates the piston balloon
to seal against the interior surface of the outer member to define
the pressure chamber, and fluid introduced through the fluid flow
port and into the pressure chamber applies a force to urge at least
the distal section of the outer member in a proximal direction.
2. The catheter according to claim 1, wherein the inner tubular
member further comprises a guidewire lumen defined therein.
3. The catheter according to claim 2, wherein the guidewire lumen
is defined by a guidewire tube disposed within the fluid lumen.
4. The catheter according to claim 1, further comprising a marker
secured to the inner tubular member to seal a distal end of the
fluid lumen distal of the fluid flow port.
5. The catheter according to claim 1, wherein the fluid lumen is
configured to receive a guidewire, the fluid lumen further
comprising proximal and distal guidewire seals to seal around a
guidewire disposed therethrough.
6. The catheter according to claim 1, wherein the proximal seal
comprises a hydrophobic material.
7. The catheter according to claim 1, further comprising a
strengthening member disposed in the inner tubular member along a
length corresponding to the pressure chamber.
8. The catheter according to claim 1, wherein the piston balloon
comprises an inflatable member made of a non-compliant
material.
9. The catheter according to claim 1, wherein the outer member
includes a proximal section proximal to the distal section, the
piston balloon being disposed proximate the proximal section.
10. The catheter according to claim 9, wherein the proximal section
of the outer member is less compliant than the distal section.
11. The catheter according to claim 9, wherein the proximal section
of the outer member comprises an outer balloon to define at least a
portion of the pressure chamber.
12. The catheter according to claim 9, wherein the proximal section
of the outer member includes a different material than the distal
section.
13. The catheter according to claim 1, wherein the distal section
of the outer member is a multi-layer construction.
14. The catheter according to claim 13, wherein the multi-layer
construction includes an outer layer of a non-compliant
material.
15. The catheter according to claim 1, wherein the outer member
comprises a braided material.
16. The catheter according to claim 1, further comprising a stent
seat at a distal end of the inner tubular member and a stent
positioned at the stent seat.
17. The catheter according to claim 16, further comprising a marker
coupled to the inner tubular member proximal to the stent seat.
18. The catheter according to claim 16, wherein the stent is
positioned between the inner tubular member and the outer member,
wherein upon proximal movement of the outer member, the stent is
exposed.
19. The catheter according to claim 1, wherein the catheter is a
rapid exchange catheter.
20. The catheter according to claim 1, further comprising a stop to
inhibit axial movement of the outer member in the proximal
direction beyond a predetermined distance.
21. The catheter according to claim 1, wherein the proximal seal
extends from the interior surface of the outer member toward the
exterior surface of the inner tubular member.
22. The catheter according to claim 1, wherein the proximal seal is
movable in the proximal direction relative the inner tubular
member.
23. The catheter according to claim 1, wherein the proximal seal
comprises at least one of hydrophilic material or molded
hydrophilic material.
24. The catheter according to claim 1, wherein the outer tubular
member includes a proximal end, the proximal end sealing coupled
with the inner tubular member to form the proximal seal.
25. The catheter according to claim 1, wherein the force is applied
proximally against the interior surface of the outer member to urge
the outer member in the proximal direction.
26. The catheter according to claim 1, wherein the proximal seal
comprises a collar.
27. The catheter according to claim 1, further comprising an
indeflator to control pressure in the pressure chamber.
28. A catheter comprising: an inner tubular member having a length
and an exterior surface, the inner tubular member defining a lumen
therein, the exterior surface defining a fluid flow port in fluid
communication with the lumen and located along a region of the
inner tubular member, the lumen further including a directional
control valve fluidly coupled with the fluid flow port, the
directional control valve having a first position and a second
position; an outer member having a distal section movable relative
to the inner tubular member, the outer member having an interior
surface facing the exterior surface of the inner tubular member; a
piston balloon coupled to the inner tubular member and in fluid
communication with the fluid flow port, the piston balloon disposed
between the inner tubular member and the outer member, the piston
balloon having a deflated condition and an inflated condition,
wherein the piston balloon in the inflated condition sealingly
engages with the interior surface of the outer member; a proximal
seal located proximal to the distal section and proximal to the
fluid flow port; and a pressure chamber defined by the proximal
seal, the piston balloon in the inflated condition, the exterior
surface of the inner tubular member, and the interior surface of
outer member, the pressure chamber being in fluid communication
with the fluid flow port; wherein the directional control valve in
the first position channels fluid from the lumen to inflate the
piston balloon to the extended position, and the directional
control valve in the second position introduces fluid through the
fluid flow port and into the pressure chamber to apply a force to
urge the outer member in a proximal direction.
29. The catheter according to claim 1, wherein the proximal seal
extends from the interior surface of the outer member toward the
exterior surface of the inner tubular member.
30. A method of deploying a catheter comprising: providing a
catheter comprising an inner tubular member having a length and an
exterior surface, the inner tubular member defining a fluid lumen
and an inflation lumen therein, the exterior surface defining a
fluid flow port in fluid communication with the fluid lumen and
located along a region of the inner tubular member, an outer member
having a distal section movable relative to the inner tubular
member, the outer member having an interior surface facing the
exterior surface of the inner tubular member, a piston balloon
coupled to the inner tubular member distal to the fluid flow port
and in fluid communication with the inflation lumen, the piston
balloon disposed between the inner tubular member and the outer
member, the piston balloon having a deflated condition and an
inflated condition, wherein the piston balloon in the inflated
condition sealingly engages with the interior surface of the outer
tubular member, a proximal seal located proximal to the distal
section and proximal to the fluid flow port, and a pressure chamber
defined by the proximal seal, the piston balloon in the inflated
position, the exterior surface of the inner tubular member, and the
interior surface of outer member, the pressure chamber being in
fluid communication with the fluid flow port; inflating the piston
balloon to the inflated condition by introducing inflation fluid
through the inflation lumen; and pressurizing the pressure chamber
by introducing pressurizing fluid through the fluid flow port to
apply a force on the proximal seal to urge the outer member in a
proximal direction.
Description
BACKGROUND OF THE DISCLOSED SUBJECT MATTER
[0001] 1. Field of the Disclosed Subject Matter
[0002] The disclosed subject matter relates to catheters used in
the delivery of medical devices, such as self-expanding stents, for
treating the luminal systems of a patient. Specifically, the
disclosed subject matter relates to a delivery catheter having a
retractable sheath moved by a piston device.
[0003] 2. Description of the Related Art
[0004] A variety of systems using a retractable sheath are known
for intraluminal delivery of a medical device, such as a stent or
filter. However, there remains a need for continued improvement of
such known delivery systems.
[0005] An example of such a system is described in U.S. Pat. No.
6,425,898 to Wilson et al., which is incorporated by reference
herein, wherein a delivery system is provided having an inner
member with a stop attached to the inner member. During deployment,
the stop prevents the stent from migrating proximally during
retraction of the sheath for stent deployment.
[0006] Conventional self-expanding stent delivery systems generally
comprise a handle portion and an elongated shaft, wherein the stent
is disposed within a delivery portion at the distal end of the
shaft. To deploy the stent, an outer sheath is provided which can
be retracted relative to the stent to release the stent from its
delivery configuration. The sheath in such systems generally spans
the full length of the catheter resulting in an increased profile
and stiffness over the entire length of the catheter. Further,
because the sheath spans the full length of the catheter there is
an increased risk of the sheath binding with other components of
the catheter during passage through the tortuous luminal system of
a patient, thus inhibiting the deployment of the stent.
[0007] Another issue with such delivery systems is that the sheath
is generally pulled back in a 1-to-1 ratio with the user's input
(force). Because the stent may embed in the outer sheath during
storage and shipping, and due to larger static friction forces, a
large amount of initial input is typically required to release the
stent which may lead to incorrect placement. When initially
releasing the stent, it may be desirable to slowly pull back the
sheath for proper placement and then more readily retract the
sheath to prevent inadvertent movement of the stent.
[0008] Further, the amount of force that is required to retract the
sheath, particularly for stents of greater length as required for
peripheral indications, can be substantial. Therefore there is a
need for an improved delivery system for self-expanding stents
having reduced force requirements for delivery of a self-expanding
stent or the like.
[0009] There thus remains a continued need for an efficient and
economic system for delivering a medical device that is easy to use
and provides accurate placement. The presently disclosed subject
matter satisfies these and other needs.
SUMMARY OF THE DISCLOSED SUBJECT MATTER
[0010] The purpose and advantages of the disclosed subject matter
will be set forth in and are apparent from the description that
follows, as well as will be learned by practice of the disclosed
subject matter. Additional advantages of the disclosed subject
matter will be realized and attained by the devices particularly
pointed out in the written description and claims hereof, as well
as from the appended drawings.
[0011] To achieve these and other advantages and in accordance with
the purpose of the disclosed subject matter, as embodied and
broadly described, the disclosed subject matter includes a catheter
comprising an inner tubular member having a length and an exterior
surface, the inner tubular member defining a fluid lumen and an
inflation lumen therein. The exterior surface defines a fluid flow
port in fluid communication with the fluid lumen and located along
a region of the inner tubular member. The catheter further includes
an outer member having a distal section movable relative to the
inner tubular member, the outer member having an interior surface
facing the exterior surface of the inner tubular member. A piston
balloon is coupled to the inner tubular member distal to the fluid
flow port and is in fluid communication with the inflation
lumen.
[0012] The piston balloon is disposed between the inner tubular
member and the outer member and having a deflated condition and an
inflated condition. The piston balloon in the inflated condition
sealingly engages with the interior surface of the outer tubular
member. A proximal seal is located proximal to the distal section
and proximal to the fluid flow port. A pressure chamber is defined
by the proximal seal, the piston balloon in the inflated position,
the exterior surface of the inner tubular member, and the interior
surface of outer member along the proximal section. The pressure
chamber is in fluid communication with the fluid flow port. Fluid
introduced through the inflation lumen inflates the piston balloon
to seal against the interior surface of the outer member to define
the pressure chamber and fluid introduced through the fluid flow
port and into the pressure chamber applies a force to urge at least
the distal section of the outer member in a proximal direction.
[0013] According to a further aspect of the disclosed subject
matter, there is provided a catheter comprising an inner tubular
member having a length and an exterior surface. The inner tubular
member defines a lumen therein and the exterior surface defines a
fluid flow port in fluid communication with the lumen and located
along a region of the inner tubular member. The lumen further
includes a directional control valve fluidly coupled with the fluid
flow port wherein the directional control valve has a first
position and a second position. An outer member having a distal
section is movable relative to the inner tubular member. The outer
member has an interior surface facing the exterior surface of the
inner tubular member. A piston balloon is coupled to the inner
tubular member and is in fluid communication with the fluid flow
port.
[0014] The piston balloon is disposed between the inner tubular
member and the outer member with the piston balloon having a
deflated condition and an inflated condition. The piston balloon in
the inflated condition sealingly engages with the interior surface
of the outer tubular member. A proximal seal is located proximal to
the distal section and proximal to the fluid flow port. The
proximal seal extends from the interior surface of the outer member
toward the exterior surface of the inner tubular member. A pressure
chamber is defined by the proximal seal, the piston balloon in the
inflated condition, the exterior surface of the inner tubular
member, and interior surface of outer member along the proximal
section. The pressure chamber is in fluid communication with the
fluid flow port. The directional control valve in the first
position channels fluid from the lumen through the fluid flow port
to inflate the piston balloon to the extended position. The
directional control valve engages to the second position to
introduce fluid through the fluid flow port and into the pressure
chamber to apply a force to urge the outer member in a proximal
direction.
[0015] According to yet another aspect of the disclosed subject
matter, there is provided a method of deploying a catheter,
comprising, providing a catheter comprising an inner tubular member
having a length and an exterior surface, the inner tubular member
defining a fluid lumen and an inflation lumen therein. The exterior
surface defines a fluid flow port in fluid communication with the
fluid lumen and located along a region of the inner tubular member.
The catheter further includes an outer member having a distal
section movable relative to the inner tubular member, the outer
member having an interior surface facing the exterior surface of
the inner tubular member. A piston balloon is coupled to the inner
tubular member distal to the fluid flow port and is in fluid
communication with the inflation lumen.
[0016] The piston balloon is disposed between the inner tubular
member and the outer member and having a deflated condition and an
inflated condition. The piston balloon in the inflated condition
sealingly engages with the interior surface of the outer tubular
member. A proximal seal is located proximal to the distal section
and proximal to the fluid flow port. A pressure chamber is defined
by the proximal seal, the piston balloon in the inflated position,
the exterior surface of the inner tubular member, and the interior
surface of outer member along the proximal section. The pressure
chamber is in fluid communication with the fluid flow port. The
method further includes inflating the piston balloon to the
inflated condition by introducing inflation fluid through the
inflation lumen and pressurizing the pressure chamber by
introducing pressurizing fluid through the fluid flow port to apply
a force on the proximal seal to urge the outer member in a proximal
direction.
[0017] It is to be understood that both the foregoing general
description and the following detailed description and drawings are
examples and are provided for purpose of illustration and not
intended to limit the scope of the disclosed subject matter in any
manner.
[0018] The accompanying drawings, which are incorporated in and
constitute part of this specification, are included to illustrate
and provide a further understanding of the devices of the disclosed
subject matter. Together with the description, the drawings serve
to explain the principles of the disclosed subject matter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The subject matter of the application will be more readily
understood from the following detailed description when read in
conjunction with the accompanying drawings, in which:
[0020] FIG. 1 is a schematic side view of a representative catheter
in accordance with the disclosed subject matter.
[0021] FIGS. 2A and 3A are cross-sectional views of different
embodiments of the inner tubular member depicting a co-axial
configuration and a multi-lumen configuration, respectively, taken
along the lines A-A of FIG. 1, according to embodiments of the
disclosed subject matter.
[0022] FIG. 4 is a schematic cross-sectional side view of a distal
end of a representative embodiment of a catheter of the disclosed
subject matter with the piston balloon in a deflated condition.
[0023] FIG. 5 is a schematic cross-sectional side view of the
catheter of FIG. 4 with the piston balloon in an inflated
condition.
[0024] FIG. 6 is a schematic cross-sectional side view of the
catheter of FIG. 5 with the piston balloon in the inflated
condition and the pressure chamber initially filled with fluid.
[0025] FIG. 7 is a schematic cross-sectional side view of the
catheter of FIG. 6 with the piston balloon in the inflated
condition and the pressure chamber in a further expansion filled
with fluid to urge the outer member in a proximal direction.
[0026] FIG. 8 is a schematic cross-sectional side view of the
catheter of FIG. 7 depicting the outer member fully retracted and
the deployment of the stent.
[0027] FIG. 9 is a schematic cross-sectional side view of the
catheter of FIG. 8 with the stent deployed and the fluid from the
pressure chamber withdrawn.
[0028] FIG. 10 is a schematic cross-sectional side view of the
catheter of FIG. 9 with the fluid withdrawn from the piston
balloon.
[0029] FIG. 11 is a schematic cross-sectional side view of the
catheter of FIG. 10 depicting the withdrawal of the catheter from
the stent.
[0030] FIG. 12 is an enlarged cross-sectional side view of another
representative embodiment of the catheter of the disclosed subject
matter with a directional flow valve.
[0031] FIG. 13 is an enlarged cross-sectional side view of another
representative embodiment of the catheter of the disclosed subject
matter when the proximal end of the outer member sealingly coupled
to the inner tubular member to form the proximal seal, and the
piston balloon in an inflated condition and the pressure chamber
filled with fluid.
DETAILED DESCRIPTION
[0032] Reference will now be made in detail to embodiments of the
disclosed subject matter, an example of which is illustrated in the
accompanying drawings. The disclosed subject matter will be
described in conjunction with the detailed description of the
system.
[0033] In accordance with the disclosed subject matter, a catheter
is provided comprising an inner tubular member having a length and
an exterior surface, the inner tubular member defining a fluid
lumen and an inflation lumen therein. The exterior surface defines
a fluid flow port in fluid communication with the fluid lumen and
located along a region of the inner tubular member. The catheter
further includes an outer member having a distal section movable
relative to the inner tubular member, the outer member having an
interior surface facing the exterior surface of the inner tubular
member. A piston balloon is coupled to the inner tubular member
distal to the fluid flow port and is in fluid communication with
the inflation lumen.
[0034] The piston balloon is disposed between the inner tubular
member and the outer member and having a deflated condition and an
inflated condition. The piston balloon in the inflated condition
sealingly engages with the interior surface of the outer tubular
member. A proximal seal is located proximal to the distal section
and proximal to the fluid flow port. A pressure chamber is defined
by the proximal seal, the piston balloon in the inflated position,
the exterior surface of the inner tubular member, and the interior
surface of outer member along the proximal section. The pressure
chamber is in fluid communication with the fluid flow port. Fluid
introduced through the inflation lumen inflates the piston balloon
to seal against the interior surface of the outer member to define
the pressure chamber and fluid introduced through the fluid flow
port and into the pressure chamber applies a force to urge at least
the distal section of the outer member in a proximal direction.
[0035] According to a further aspect of the disclosed subject
matter, there is provided a catheter comprising an inner tubular
member having a length and an exterior surface. The inner tubular
member defines a lumen therein and the exterior surface defines a
fluid flow port in fluid communication with the lumen and located
along a region of the inner tubular member. The lumen further
includes a directional control valve fluidly coupled with the fluid
flow port wherein the directional control valve has a first
position and a second position. An outer member having a distal
section is movable relative to the inner tubular member. The outer
member has an interior surface facing the exterior surface of the
inner tubular member. A piston balloon is coupled to the inner
tubular member and is in fluid communication with the fluid flow
port.
[0036] The piston balloon is disposed between the inner tubular
member and the outer member with the piston balloon having a
deflated condition and an inflated condition. The piston balloon in
the inflated condition sealingly engages with the interior surface
of the outer tubular member. A proximal seal is located proximal to
the distal section and proximal to the fluid flow port. The
proximal seal extends from the interior surface of the outer member
toward the exterior surface of the inner tubular member. A pressure
chamber is defined by the proximal seal, the piston balloon in the
inflated condition, the exterior surface of the inner tubular
member, and interior surface of outer member along the proximal
section. The pressure chamber is in fluid communication with the
fluid flow port. The directional control valve in the first
position channels fluid from the lumen through the fluid flow port
to inflate the piston balloon to the extended position. The
directional control valve engages to the second position to
introduce fluid through the fluid flow port and into the pressure
chamber to apply a force to urge the outer member in a proximal
direction.
[0037] According to yet another aspect of the disclosed subject
matter, there is provided a method of deploying a catheter,
comprising, providing a catheter comprising an inner tubular member
having a length and an exterior surface, the inner tubular member
defining a fluid lumen and an inflation lumen therein. The exterior
surface defines a fluid flow port in fluid communication with the
fluid lumen and located along a region of the inner tubular member.
The catheter further includes an outer member having a distal
section movable relative to the inner tubular member, the outer
member having an interior surface facing the exterior surface of
the inner tubular member. A piston balloon is coupled to the inner
tubular member distal to the fluid flow port and is in fluid
communication with the inflation lumen.
[0038] The piston balloon is disposed between the inner tubular
member and the outer member and having a deflated condition and an
inflated condition. The piston balloon in the inflated condition
sealingly engages with the interior surface of the outer tubular
member. A proximal seal is located proximal to the distal section
and proximal to the fluid flow port. A pressure chamber is defined
by the proximal seal, the piston balloon in the inflated position,
the exterior surface of the inner tubular member, and the interior
surface of outer member along the proximal section. The pressure
chamber is in fluid communication with the fluid flow port. The
method further includes inflating the piston balloon to the
inflated condition by introducing inflation fluid through the
inflation lumen and pressurizing the pressure chamber by
introducing pressurizing fluid through the fluid flow port to apply
a force on the proximal seal to urge the outer member in a proximal
direction.
[0039] As disclosed herein, the device presented herein can be used
for treating the luminal system of a patient. In particular, the
disclosed subject matter is particularly suited for treatment of
the cardiovascular system of a patient, such as delivery of a
medical device into the vasculature. The catheter and method of the
disclosed subject matter will be described in further detail and in
conjunction with each other.
[0040] Solely for purpose of illustration, reference will now be
made in detail to specific embodiments, examples of which are
illustrated in the accompanying drawings. The examples are not
intended to limit the scope of the disclosed subject matter in any
manner. For the purposes of this disclosure, like reference numbers
in the drawings shall refer to like features unless otherwise
indicated.
[0041] Solely for purpose of illustration, FIG. 1 illustrates a
representative embodiment of a catheter having a hydraulic delivery
system for a medical device, at least a portion of which can be
delivered within a vasculature or other body lumen, as shown
schematically in the accompanying figures. The catheter 100
generally comprises an inner tubular member 110 having a length and
an exterior surface, wherein the inner tubular member defines a
fluid lumen and an inflation lumen therein, as further discussed
below.
[0042] The inner tubular member 110 of the catheter 100 can include
a variety of suitable configurations. For example, the inner
tubular member can comprise an over the wire (OTW) configuration
with a guidewire lumen extending generally the entire length of the
inner tubular member or can comprise a rapid exchange configuration
(RX) with a guidewire lumen extending from a proximal guidewire
port to a distal end as generally known to one of skill in the art.
In either the OTW or the RX configurations, the inner tubular
member can furthermore have a co-axial arrangement or a multi-lumen
arrangement.
[0043] Solely for purpose of illustration, FIG. 2A depicts a
representative cross-sectional view of a co-axial arrangement along
lines A-A of FIG. 1. The co-axial arrangement includes an inner
tubular member 110 and a guidewire tube 321 disposed therein. The
guidewire tube 321 defines a guidewire lumen 320 therethrough. In
this embodiment, a single lumen is defined in the annular space
between the inner tubular member 110 and the guidewire tube 321. As
described in detail herein, the single lumen can define both a
fluid lumen and an inflation lumen in accordance with the disclosed
subject matter. Furthermore, the guidewire lumen can be omitted if
a proximal seal and a distal seal are provided and configured to
allow a guidewire to extend therethrough. The inner tubular member
110 can be a single tube or an assembly of components coupled
together along its length.
[0044] Alternately, FIG. 3A depicts a representative
cross-sectional view of a multi-lumen arrangement. Solely for
purpose of illustration, the inner tubular member 110 can be a
monolithic member with a multi-lumen configuration. In such
embodiment, the inner tubular member 110 defines an inflation lumen
24, a guidewire lumen 320, and a fluid lumen 310 therein. Solely
for purpose of illustration, a monolithic multi-lumen inner tubular
member 110 is also shown schematically in FIGS. 4-11. The inner
tubular member 110 has a proximal end portion, a distal end
portion, and a length. As depicted in FIGS. 4-11, the guidewire
lumen 320 extends along at least a distal end portion of the inner
tubular member, whereas the fluid lumen 310 and the inflation lumen
24 are defined at least along a portion of the proximal end portion
therein.
[0045] With reference to FIGS. 4-11, the guidewire lumen 320 is
configured to receive a guidewire for delivery of the catheter 100
through tortuous pathways of a vasculature or other body lumen. In
an OTW catheter, the guidewire lumen 320 extends along the length
of the catheter 100. In an RX catheter, the guidewire lumen 320
extends along a portion of the length of the catheter along a
distal end portion of the inner tubular member. The guidewire lumen
320 includes a proximal guidewire port at a proximal end of the
guidewire lumen (not shown). The location of the proximal guidewire
port along the length of the inner tubular member will depend on
whether the catheter is an OTW catheter or an RX catheter, as is
known. The guidewire lumen has a distal guidewire port 430 at a
distal end of the catheter 100. For example, and as embodied
herein, the catheter 100 has a distal tip 460 at the distal end to
define the distal guidewire port 430, as shown in FIG. 4. The
distal tip 460 can further define the distal end for a stent seat 3
or the like, as described further below.
[0046] Alternatively, and in lieu of a separate guidewire lumen
defined within the monolithic inner tubular member, a separate
guidewire tube can be disposed in either the fluid lumen or the
inflation lumen. In a further embodiment, the separate guidewire
lumen can be omitted if either the fluid lumen or the inflation
lumen includes a seal assembly configured to receive a guidewire
therethrough.
[0047] As depicted in FIG. 4, and as previously noted, the inner
tubular member 110 further defines a fluid lumen 310 and an
inflation lumen 24 therein. The exterior surface 111 of the inner
tubular member 110 defines a fluid flow port 420 in fluid
communication with the fluid lumen 310 and located along a region
of the inner tubular member. Fluid from an external source (not
shown) therefore can be introduced through the fluid lumen 310 and
exit though the fluid flow port 420.
[0048] As depicted in FIGS. 4-11, the exterior surface 111 of the
inner tubular member 110 further defines the inflation port 242 or
the like in fluid communication with the inflation lumen 24. The
fluid flow port 420 and the inflation port 242 therefore define
access points for fluid to exit the fluid lumen 310 and the
inflation lumen 24, respectively. An adapter (not shown) is
provided at the proximal end of the catheter for access to the
inflation lumen 24 and the fluid lumen 310, respectively. The
adapter can be configured to connect a fluid source (not shown) to
the inflation lumen 24 and the fluid lumen 310, respectively. A
conventional device, such as but not limited to an indeflator or a
syringe, can introduce the fluid to the inflation lumen and fluid
lumen, respectively, as described further below.
[0049] In an alternate embodiment and as previously noted, the
fluid lumen 310 and the inflation lumen 24 can be combined and
comprise a single shared lumen. FIG. 2A depicts an example of a
cross-section of the inner tubular member 110 with a co-axial
arrangement adapted for a single shared lumen. The guidewire lumen
is positioned within the shared lumen, as provided in FIG. 2A. Such
coaxial configurations allow for reduced diameter of the inner
tubular member 110, and thus reduced profile. Further, the
guidewire lumen can be formed by a thin membrane of suitable
strength to prevent the guidewire from penetrating therethrough.
For the co-axial arrangement the single shared lumen, fluid can be
introduced annularly between the guidewire tube 321 and the inner
tubular member 110 and thus outside the guidewire lumen 320.
[0050] With reference again to FIGS. 4-11, the fluid flow port 420
and the inflation port 242 are located along the inner tubular
member 110 at different locations, as previously described. Solely
for purpose of illustration, FIG. 12 depicts an enlarged schematic
view of the fluid flow port 420 and the inflation port 242 for a
co-axial configuration. A seal or stop 721 is provided distal to
the inflation port 242 to prevent fluid in the fluid lumen from
flowing further distally. The stop 721 allows the guidewire to
continue in the guidewire lumen 320.
[0051] In accordance with another aspect of the disclosed subject
matter as depicted in FIG. 12, a directional control valve 800 or
the like can be provided. For example, and as embodied herein with
reference to the co-axial arrangement of FIG. 12, a directional
control valve 800 or a suitable valve or seal is provided for
selective operation to direct fluid through the fluid flow port 420
or inflation port 242 or both. The directional control valve 800
allows the fluid initially to bypass the fluid flow port 420 and to
discharge or exit from the inflation port 242. Upon selective
operation, such as when a predetermined flow or pressure is reach
or by remote activation, the directional control valve 800 can
redirect the fluid in the lumen to exit the fluid flow port 420, as
depicted in FIG. 12. Similarly, and as described further herein,
the directional control valve 800 controls the sequence in which
fluid is withdrawn through the fluid port 420 and the inflation
port 242, respectively.
[0052] As depicted in FIGS. 4-11 and as previously noted, the
catheter further includes an outer member or sheath 120 having a
distal section moveable relative to the inner tubular member 110.
The outer member 120 has a proximal section, a distal section, and
an interior surface 121. The inner tubular member 110 is positioned
within the outer member 120 at least at the distal section of the
catheter 100. As such, the exterior surface 111 of the inner
tubular member 110 is directed toward the interior surface 121 of
the outer member 120. With reference to FIG. 4, the outer member
120 is movable relative to the inner tubular member 110, such that
the distal section of the outer member 120 can be retracted in a
proximal direction A toward the proximal end of the catheter. As
further shown in FIG. 4, the outer member 120 is disposed only at
the distal end portion of the catheter 100, although the outer
member can extend a greater length of the inner tubular member, if
needed.
[0053] As depicted in FIGS. 4-11 and as previously noted, the
catheter further includes a piston balloon 60 coupled to the inner
tubular member 110 distal to the fluid flow port 420 and in
communication with the inflation lumen 242. The piston balloon 60
is disposed between the inner tubular member 110 and the outer
member 120 for engagement with outer member 120. The piston balloon
60 has a deflated condition and an inflated condition, as depicted
schematically in FIGS. 4 and 5, respectively. When in the inflated
condition as depicted in FIG. 5, the piston balloon 60 is in
sealing engagement with the interior surface 121 of the outer
member 120.
[0054] As shown in FIG. 4, the piston balloon 60 is coupled to the
inner tubular member 110 distal to the fluid flow port 420. The
piston balloon 60 is in fluid communication with the inflation
lumen 24, such as via the inflation port 242 as embodied herein.
Fluid therefore can be introduced into the inflation lumen 24 at
the proximal end of the catheter 100 and exit through the inflation
port 242 to inflate the piston balloon 60. The piston balloon 60 is
secured in a fixed location on the inner tubular member 110. As the
piston balloon 60 inflates, the outer member 120 can be configured
or formed of a suitable material to increase in diameter to
maintain a seal against the piston balloon while still permitting
axial movement of the outer member 120 thereacross. The piston
balloon 60 can comprise suitable materials, for example, but not
limited to, Pebax or Nylon, and/or a non-compliant material, as
further discussed herein.
[0055] Additionally and with reference to the embodiment of FIG. 4,
the catheter 100 includes a proximal seal 720 located proximal to
the distal section of the outer member 120 and proximal to the
fluid flow port 420. Particularly, the proximal seal defines in
part a pressure chamber proximal to the piston balloon. For
example, the proximal seal 720 can extend from the interior surface
121 of the outer member 120 toward the exterior surface 111 of the
inner tubular member 110. The proximal seal 720 is located proximal
to fluid flow port 420. The proximal seal 720 is fixed to the
interior surface 121 of the outer member 120 and moves freely
relative with respect to the inner tubular member 110. The movement
of the proximal seal 720 in the proximal direction A, such as upon
application of a force as described further below, effectuates the
movement at least of the distal section of the outer member 120. A
distal seal 620 can also be provided at a location distal to the
piston balloon 60. The distal seal 620 embodied herein extends from
the interior surface 121 of the outer member 120 toward the
exterior surface 111 of the inner tubular member 110. The distal
seal 620 is fixed to the interior surface 121 of the outer member
120 and moves freely relative with respect to the inner tubular
member 110.
[0056] As such, and as embodied herein, a pressure chamber 80 is
defined by the proximal seal 720, the piston balloon 60, the
exterior surface 111 of the inner tubular member 110, and the
interior surface 121 of outer member 120. The pressure chamber 80
is in fluid communication with the fluid flow port 420. As the
pressure chamber 80 is pressurized by the introduction of fluid
through the fluid flow port 420, the proximal seal 720 moves in the
proximal direction A to thus urge at least the distal section of
the outer member 120 in the proximal direction A.
[0057] In operation and as shown in FIG. 5, when the piston balloon
60 is in the inflated condition, pressurized fluid is introduced
into the fluid lumen 310 and exits through the fluid flow port 420
into the pressure chamber 80. Once sufficient fluid is introduced
into the pressure chamber 80 as shown in FIG. 6, the pressure
chamber 80 pressurizes and an axially directed force is applied on
the proximal seal 720 and the inflated piston balloon 60. Since the
inflated balloon 60 is locally fixed to the inner tubular member
110 and the proximal seal 720 is moveable proximally, the generated
force moves the proximal seal 720 in the proximal direction A.
Since the proximal seal 720 of this embodiment is coupled to the
outer member 120, the distal section of the outer member 120 is
likewise moved in the proximal direction A, generally proportional
with the proximal seal 720. The proximal seal 720, and thus the
outer member 120, will continue to move in the proximal direction A
until the force F is no longer generated.
[0058] Alternatively or in addition thereto as shown in FIGS. 8-11,
the outer member 120 moves in the proximal direction A until a stop
710 comes into engagement with the distal end of the outer member
120. Such pressure can be controlled externally, for example, by a
suitable indeflator or pressure source with locking mechanism to
control the resulting force acting on the proximal seal, as further
discussed herein.
[0059] With reference to FIG. 13 and in accordance with the
disclosed subject matter, alternative arrangements can be used for
the proximal seal to define the pressure chamber 80. For example,
and in lieu of a movable proximal seal as previously discussed, the
proximal end of the outer member 120 can alternatively be sealingly
coupled with the inner tubular member 110. Solely for purpose of
example, the proximal end of the outer member 120 can be secured
directly to the inner tubular member 110 in a manner to allow outer
member 120 to invert in on the proximal direction A. Alternatively,
the proximal end of the outer member 120 can be heat bonded to the
inner tubular member 110. In another arrangement, the proximal end
of the outer member 120 can be bonded to the inner tubular member
110 with a suitable adhesive. Solely for purpose of illustration as
depicted in FIG. 13, a collar 723 can be provided to secure the
proximal end of the outer member 120 to the inner tubular member
110 in a fixed position. The collar 723 is secured to the inner
tubular member 110 at a location proximal to the fluid flow port
420. The collar 723 thus forms a proximal seal for a pressure
chamber 80, as depicted in FIG. 13. As the pressure chamber 80 is
pressurized by fluid exiting the fluid flow port 420, the outer
member 120 inverts in the proximal direction A as depicted in the
phantom lines of FIG. 13. In this manner, the distal section of the
outer member 120 will be drawn or move in the proximal direction A
to expose a distal end of the inner tubular member 110. The collar
723 can be made of a suitable material, for example, a polymer
heat-shrink tubing adapted to compress onto the inner tubular
member. Suitable materials capable for an inverting outer member
adapted to seal with the piston balloon and invert as described
include, but are not limited to, pebax, nylon, polyethylene, or
some combinations thereof. Alternative proximal seals likewise can
be used or formed to define a pressure chamber 80 suitable to move
or retract at least the distal section of the outer member 120, in
accordance with the subject matter disclosed herein.
[0060] In accordance with another aspect of the disclosed subject
matter, the pressure chamber 80 can be configured to increase in
cross section when pressurized, such that a greater force is
generated on the proximal end of the pressure chamber 80 due to the
increased surface area. For example, the proximal section of the
outer member 120 can be constructed to expand as it is pressurized,
yet the distal section can be configured to maintain adequate hoop
strength to retain the constrained stent or the like until
retracted.
[0061] To accommodate relatively high fluid pressures to retract
outer member 120, the pressure chamber 80 is formed to withstand
such pressures with minimal leakage. A variety of suitable seal
constructions and materials for the embodiments herein described
can be used, such as, but not limited to, sliding seals, rings,
cups seals, lips seals, and compressed bushings. For example each
seal can be formed as a separate member and attached to the
corresponding member, or can be formed as part of the tubular
member, as further discussed herein.
[0062] In accordance with another aspect of the disclosed subject
matter, and as embodied herein, for purposes of discussion, a seat
or similar platform can be defined distal to the piston balloon for
delivery of a medical device. For example, and as depicted in FIG.
4, the catheter 100 can include a medical device, such as a stent
2, positioned at the stent seat 3 between the inner tubular member
110 and the outer member 120 at the distal end of the catheter 100.
When initially in its extended position as shown in FIG. 4, the
outer member 120 retains the stent 2 in a compressed or delivery
condition. When the distal section of outer member 120 is retracted
as shown in FIGS. 5-11, the stent 2 is allowed to expand to its
deployed condition, further discussed below. The self-expanding
stent 2 is exposed by the movement of the outer member or sheath
120 in the proximal direction A. As described further herein, the
catheter of the disclosed subject matter can be configured to
deliver a medical device, such as the stent 2, of any suitable
length. That is, the catheter 100 can be configured to generate a
force sufficient to retract the outer tubular member 120, wherein
the generated force is greater than the resistance force caused by
the medical device acting on the outer tubular member.
[0063] Once the stent 2 or device is fully exposed and deployed as
shown in FIG. 8, the fluid in the pressure chamber 80 can be
removed via the fluid flow port 420 in a suitable manner. For
instance, a syringe can withdraw the fluid, i.e. provide negative
pressure as shown in FIGS. 9-10. Further, the fluid in the balloon
60 can similarly be withdrawn via the inflation lumen 24. The
withdrawal of fluid deflates the piston balloon 60 to a deflated
condition as shown in FIGS. 10-11, so that the catheter 100 can be
withdrawn from the luminal system of a patient. As the piston
balloon 60 deflates, the seal created by the piston balloon in the
extended position is annulled. Accordingly, when the piston balloon
60 no longer abuts against the interior surface of the outer
member, the fluid between the exterior surface of the inner tubular
member 110 and the interior surface of the outer member 120 can
move distal to the piston balloon and can further move out the
distal end of the catheter, if desired. The progression of the
movement of the outer member 120 to deploy the stent seat 2 is
depicted in FIGS. 4-11, as described herein.
[0064] Additionally, or alternatively, the catheter 100 can include
a bellows or bladder component within the pressure chamber to
prevent leaks (not shown). For example, the bellows or bladder
component can be coupled to the exterior surface of the inner
tubular member 110 and is in fluid communication with the fluid
flow port 420, wherein fluid introduced through the fluid flow port
420 expands the bellows component to assist in retracting the
distal section of the outer member.
[0065] In accordance with another aspect of the disclosed subject
matter, spacer elements (not shown) can be provided within the
pressure chamber 80. The spacer elements can prevent the outer
member 120, proximal seal 720 and distal seal 620, if provided,
from being collapsed during delivery and storage of the catheter.
The spacer elements can also reduce the amount of fluid needed to
retract the outer member. The spacer elements can be made of any of
a variety of suitable shapes and materials, such as ring members
having diameters corresponding to the inner and outer diameters of
the inner and outer members, respectively.
[0066] If desired, a bumper or stop member can be provided to
prevent the distal end of the outer member from being retracted
proximally beyond the piston balloon. For example, and as shown in
FIG. 4, the catheter 100 can include a stop 710 secured to the
inner tubular member 110. The stop 710 is disposed distal to the
pressure chamber 80 and proximal to the medical device to be
delivered, e.g. the stent 2. Furthermore, for co-axial
configurations, the stop 710 can be configured to seal the fluid
lumen 310 with the guidewire lumen 320 extending therethrough. Stop
710 can be made of or include a radiopaque material. The
radiopacity thus can provide enhanced visibility for the suitable
placement of the catheter at the treatment site such as a
radiopaque marker. For example, the marker can be a radiopaque
metallic ring, or made of a tungsten loaded polymer for increased
softness and flexibility. Other suitable markers known can be
used.
[0067] In accordance with an embodiment of the disclosed subject
matter, a method of deploying a catheter as previously described is
provided. Solely for purpose of illustration, reference will be
made to the embodiment of FIGS. 4-11. However, the disclosed method
is likewise applicable to alternative embodiments of the catheter,
such as shown in FIG. 13. As depicted in FIG. 4, the piston balloon
60 is in the deflated condition 62 and the stent 2 is in a
compressed position. In FIG. 5, fluid is introduced into the
inflation lumen 24 to inflate the piston balloon 60. The piston
balloon 60 is in the inflated condition and is in sealing
engagement with the interior surface 121 of the outer member 120. A
pressure chamber 80 is defined by the proximal seal 720, the piston
balloon 60, the exterior surface 111 of the inner tubular member
110, and the interior surface 121 of outer member 120. At this
point, the inflation of the piston balloon 60 has not caused
movement of the outer member 120 and the stent 2 remains in the
first position.
[0068] FIG. 6 depicts fluid introduced through the fluid lumen 310
and exiting through the fluid flow port 420 into the pressure
chamber 80. The pressure in the pressure chamber 80 has not
exceeded the force required to move the proximal seal 720 and thus
the stent 2 remains in the first or compressed position.
[0069] In FIG. 7, the proximal seal 720 of FIG. 6 has shifted
length d in the direction A to a new position represented by
proximal seal 720. The starting position of the proximal seal 720
is represented by the dotted lines in FIG. 7. As the proximal seal
720 moves in the direction A, the outer member 120 is urged in
direction A and moves generally proportionally. As represented by
FIG. 7, the distal section of the outer member 120 moves generally
the same length d in the direction of A to partially expose the
stent 2. The proximal seal 720 and outer member 120 can be
configured to provide a 1:1 ratio of the movement of the outer
member 120 and the movement of the proximal seal 720, or other
suitable ratios as desired. In FIG. 7, the stent 2 has partially
expanded.
[0070] FIG. 8 shows a further progression in comparison with FIG.
7. In FIG. 8, the stent 2 has been fully exposed due to the
retraction of the distal section of the outer member 120 in the
direction A. The retraction corresponds to the extension in length
of the pressure chamber 80 as more fluid continues to pressurize
the pressure chamber 80. The continued pressurization urges the
proximal seal 720 in the direction A, as shown by the new position
of the proximal seal at 720. In this embodiment, the proximal seal
720 has shifted a full distance f in relation to the starting
position. The full distance f is at least equal to the length of
the stent 2 or device to be delivered. The starting position of the
proximal seal 720 is represented by the phantom lines. Likewise,
the distal section of the outer member 120 has shifted the full
distance f, as depicted in FIG. 8. The retraction of the outer
member 120 allows for deployment of the stent 2.
[0071] As depicted in FIG. 9, once the stent seat 3 is fully
exposed and the stent 2 contained therein is released, the fluid
from the pressure chamber 80 can be withdrawn. Likewise the fluid
from the inflated piston balloon 60 can also be withdrawn, as
depicted in FIG. 10. In one embodiment, once the piston balloon 60
is deflated, the fluid remaining between the interior surface of
the outer member and the exterior surface of the inner tubular
member can be released into the patient.
[0072] Once the fluid from the pressure chamber 80 and the piston
balloon 60 is withdrawn, the catheter 100 can be removed from the
vasculature as the stent 2 remains in the second or expanded
position, as depicted in FIG. 11.
[0073] Embodiments of the disclosed subject matter allow the
pressure chamber to operate with a variety of different suitable
pressures. Solely for purpose of illustration, in one embodiment
the pressure chamber can handle a positive pressure of up to 750
psi, and a negative pressure of approximately 14 psi.
[0074] In accordance with another aspect of the disclosed subject
matter, an indeflator can be provided to control the inflation and
deflation of the piston balloon and the outer tubular member. A
pressure gauge can be provided with the indeflator to monitor the
pressure system of the catheter. The indeflator allows for the
rapid release of hydraulic pressure to stop or inhibit the
deployment of the stent. The indeflator can also be configured to
create and/or maintain negative pressure in the catheter. For
example, by creating a vacuum, the outer tubular member disclosed
herein can be configured to decrease in profile and/or lock in
position. The indeflator can have a locking mechanism to maintain
negative pressure in the catheter. The indeflator can further
create a vacuum that decreases the profile of the catheter. An
example of a suitable indeflator is an Atrion indeflator Atrion
Medical--55ATM.
[0075] The inner tubular member and outer tubular member each can
be a single piece construction, or an assembly of components, and
can be made of any suitable material. For example, suitable
materials include, but are not limited to, polymer materials such
as nylon, urethane, polyurethane, PEEK, PTFE, PVDF, Kynar, PE,
HDPE, a trilayer material including L25, Plexar, PEBAX or
polyethylene of various suitable densities. Furthermore, at least a
portion of the inner tubular member can be constructed of an alloy
or metallic material, such as stainless steel hypodermic tubing.
Example constructions for the outer member include a single layer
of PEEK, Polyimide, or Radel; a trilayer material of L25, Plexar,
HDPE; or a braided tube with a PTFE or eTFE liner, a Polyimide
middle layer with braiding, and a Pebax 72D or Vestamid outer
layer.
[0076] It is further contemplated that the inner tubular and outer
member can be constructed of other biocompatible material. As such,
the inner tubular and outer member of the catheter can be
constructed from the above-identified polymers, combinations or
blends of these polymers, whether alone or in combination with
other materials, or other bioabsorbable materials. The inner
tubular member and outer member can also be reinforced by the
addition of a strengthening member, such as, for example and not
limited thereto, a wire coil. In one embodiment, the inner tubular
member is reinforced by the addition of a strengthening member
along a length corresponding to the pressure chamber, further
described herein.
[0077] As a further alternative, the inner tubular member and/or
the outer member each can be constructed of multiple outer tubular
members. The one or more proximal stops can further form a joint
for two adjacent outer tubular members. The outer member can also
be constructed of a composite comprising a fabrication of several
different materials, such as a co-extrusion of different polymers,
or a fiber-reinforced composite material such as fiber reinforced
resin materials or braided materials. Solely for purpose of
illustration, further embodiments can include a braided tube with a
PTFE liner, a Polyimide middle layer with braiding and a Pebax 72D
outer layer. Additionally, to improve flexibility, helical or
spiral member configurations can be used in the construction of the
inner and outer members.
[0078] The proximal section of the outer member can be formed of
any suitable material or composite that allows a seal, when the
piston balloon is inflated and/or the pressure chamber is
pressurized. Solely for purpose of illustration, the proximal
section of the outer member can include an elastic or compliant
material that permits the outer member to expand initially upon
expansion of the piston balloon but reverts back when the piston
balloon is deflated. Alternatively, the proximal section can be
made of a non-compliant material, similar to a conventional
dilatation balloon, which is folded to allow for collapse to a
small profile. Furthermore, the outer member can be configured to
adjust in collapse of the piston balloon when deflated, such as
with a semi-compliant material. Exemplary constructions for the
outer tubular member include a single layer of polyimide or PEEK; a
trilayer material of L25, Plexar, HDPE; or a braided tube with a
PTFE liner, a Polyimide middle layer braiding middle layer, and a
Pebax 72D outer layer.
[0079] Additionally or alternatively, the outer member can have a
rigid inner layer and a flexible outer layer, wherein the rigid
layer is made of a material that is dissolvable by a selected fluid
medium. The pressure chamber can be pressurized with the fluid
medium, dissolving the rigid structure and thereby allowing the
flexible outer layer to expand in diameter. The outer member can
also be formed of a suitable shape-memory material configured to
expand across the pressure chamber when the chamber is filled with
a hot fluid. As another alternative, the outer member can have a
bi-stable design that transitions from a locked or contracted
configuration during delivery to an unlocked or expanded
configuration upon increased fluid pressure in the pressure
chamber.
[0080] The outer member can further be provided with an inner layer
attached to or formed with an outer layer. The inner layer or liner
can include a lubricious material to facilitate the sliding of the
outer member in the proximal direction when the outer member is
retracted. For example, different types of polymers such as PTFE or
high-density polyethylene (HDPE) can be used for the inner layer.
Additionally, other lubricious polymers can be used. The outer
layer, as embodied herein, provides sufficient strength to capture
the intravascular prosthesis therein, as well as allow movement in
the proximal direction A. The multiple layers can be formed
separately and adhered or bonded together or co-extruded as a
single member.
[0081] In further accordance with the disclosed subject matter, the
outer member can include a reinforcing layer at the distal end
portion corresponding to the location of the stent seat 3 and
disposed between the outer layer and the inner layer, such as a
braided or coiled material. For example, the reinforcing layer can
be provided in the form of a braided stainless steel tube or sheet
or the like. The braid can include flattened filaments, as opposed
to having filaments with a round cross-section. Alternatively, the
reinforcement can be in the form of a tube including woven fabric
or appropriately oriented filaments, such as carbon fibers encased
in a polymeric matrix. Likewise, such reinforcing fibers could
additionally or alternatively be incorporated into inner layer
and/or outer layer during the manufacturing process.
[0082] In embodiments where the outer member comprises an inner
layer, outer layer and a reinforcing layer, the outer member can be
formed in at least the following manner by way of example. First,
the inner layer is formed through a tubular extrusion process, and
disposed about a forming mandrel (not shown). The fanning mandrel,
as embodied herein, has a shape that corresponds to the desired
shape of the inside of the outer member. Next, the reinforcing
layer, which can be provided in the form of a stainless steel braid
material, is positioned over a predetermined length of inner layer.
Next, the outer layer is extruded and positioned over the
reinforcing layer. The outer layer can be provided in the form of
two separate tubular members that are overlapped slightly at their
ends over a reinforcing layer. Each portion of outer layer can be a
different material selected to provide a different durometer as
described above. The two portions of outer layer can overlap by an
amount, such as but not limited to, about 0.1 inches. Next, a
sleeve of heat shrinkable material is positioned over the entire
outer member assembly. Finally, heat is applied to the assembly.
When heat is applied, the heat shrinkable tubing shrinks, and
causes the inner layer to fuse with outer layer, trapping the
reinforcing layer therebetween. The heating process also causes
inner layer to conform to the shape of the forming mandrel. After
the assembly cools, the heat shrinkable tubing is cut away, leaving
behind the outer member.
[0083] In accordance with another embodiment, the outer member can
be a multilayer tube or balloon including a flexible layer and a
rigid layer having a brittle structure configured to fracture upon
expansion. The rigid layer can constrain and axially lock a medical
device during shipping, storage and delivery, but can rupture upon
initial pressurization of the pressure chamber. Once the rigid
layer is broken, the flexible layer can maintain a seal while
significantly increasing in diameter over the pressure chamber. The
multilayer outer tubular member can have a brittle outer layer and
a flexible inner layer.
[0084] Additionally, the inner tubular member and/or outer tubular
member can be constructed from PE, polypropylene, Kynar, or
urethane by an extrusion process using an extruder such as that
available any of a number of known suppliers. The materials can be
post processed in a number of ways including, for example and not
by way of limitation, extrusion, molding, such as by injection or
dipping, textile processing such as weaving or braiding, and
forming. Forming processes that can be suitable are rolling and
welding sheets of material or vacuum forming into tubular shapes,
to name only a few examples.
[0085] The inner tubular member and/or outer member can be further
coated with any of a variety of materials and techniques to enhance
performance if desired, including a number of suitable coatings and
coating techniques subject to patent matters owned by Abbott
Laboratories such as U.S. Pat. No. 6,541,116, U.S. Pat. No.
6,287,285, and U.S. Pat. No. 6,541,116, the entireties of which are
hereby incorporated by reference. For example, possible coating
materials include lubricious materials such as Teflon.RTM., and
hydrophobic materials such as silicone lubricant dispersion PN
4097, or hydrophilic materials such as hydrogel.
[0086] The inner tubular member and/or outer member can have any
suitable cross-sectional shape, including elliptical, polygon, or
prismatic, although a circular cross-section generally is
preferred. The inner tubular member and/or outer member can also
have any suitable size and diameter depending upon the desired
application. The catheter is suitably sized and configured for
delivery within a corresponding body lumen for the intended
indication, such as a vasculature for vascular intervention. The
inner and outer tubular members can also have any suitable size and
diameter depending upon the desired application.
[0087] The seals of embodiments of the disclosed subject matter can
be formed of any suitable materials. For example and not limited
thereto, the seal can be silicon or a rubber such as Buna, EPDM,
Viton, or Neoprene. In other embodiments, the seal can be formed of
a low durometer rubber having a compressed condition and an
expanded condition. The seal can be significantly compressed and
deformed in the initial delivery configuration, and later
transitioning to the expanded condition when the pressure chamber
is pressurized. Alternatively, the seal can be made of a
hydrophilic polymer that absorbs fluid in the pressure chamber so
as to expand proportionally with the outer member. The proximal
seal can comprise an expandable material or composite of materials
to match the dimensions of the outer member. For example, the seal
can expand in cross-dimension with the outer member to maintain an
adequate seal. Thus, as the cross-dimension of the pressure chamber
expands, the exposed surface area of the seal also increases,
resulting in a proportional increase in retraction force generated
at a given fluid pressure within the pressure chamber. Thus, an
expanding pressure chamber provides for greater retraction force at
a given pressure.
[0088] The seal assemblies can further include bushings (not shown)
to provide a backing to the seals, as known in the art. In
accordance with an aspect of the disclosed subject matter, the
bushings can be constructed of any suitable material, including,
but not limited to, PEEK, Pebax, HDPE, LDPE, mixtures of HDPE and
LDPE, a blend of Nylon L75/L25, and the like. In one embodiment,
the bushings comprise a metallic material, combination low density
polyethelene, silicon, nitril, soft Pebax 30, or other blends of
suitable material, and can furthermore have a coating.
[0089] According to an embodiment of the disclosed subject matter,
the proximal seal and/or distal seal, if provided, can be formed as
a separate member and attached to the corresponding tube member, or
can be formed as part of the tubular member. For purposes of
illustration and not limited thereto, hydrophilic material can be
used for the proximal and/or distal seals. For purposes of
illustration and not limited thereto, a suitable hydrophilic
material can be used for the seals. For purposes of illustration
and not limited thereto, hydrophilic material, such as, but not
limited to, HydroMed.TM., Hydrothane.TM., Hydak (R), can be used
for the seals. Seals made of such material can be configured to
swell when exposed to an aqueous environment, thus sealing more
tightly while maintaining lubricity. The seals can comprise an
expandable material or composite of materials to increase
accordingly to match the dimensions of the outer tubular member.
That is, the seal expands with the outer tubular member to maintain
an adequate seal. As the pressure chamber expands, the exposed
surface area of the seal also increases, resulting in a
proportional increase in retraction force at a given fluid
pressure. Thus, an expanding pressure chamber provides for greater
retraction force at a given pressure.
[0090] Alternatively, the proximal and distal seals can be coated
with a hydrophobic layer such as oil or wax or made of hydrophobic
material such as a fluorocarbon or olefins like polypropylene to be
used with a suitable pressurized fluid. Solely, for purpose of
illustration, silicone seals with a Hydromer 2314-172 coating. In
one embodiment, O-rings can be used for the seal constructions
comprised of silicone, buna, or other suitable elastomers.
Furthermore, for purpose of example, but not limited thereto, the
seal can include soft tubing such as a low durometer Pebax or
Santoprene. Additionally or alternatively, a high viscosity
hydraulic fluid can be used to inhibit leaks.
[0091] In embodiments of the disclosed subject matter, the inner
tubular member and/or outer member can furthermore be manufactured
using a variety of known and suitable techniques.
[0092] While the disclosed subject matter is described herein in
terms of certain preferred embodiments, those skilled in the art
will recognize that various modifications and improvements can be
made to the disclosed subject matter without departing from the
scope thereof. Additional features known in the art likewise can be
incorporated, such as disclosed in U.S. Pat. No. 7,799,065 to
Pappas, which is incorporated in its entirety by reference herein.
Moreover, although individual features of one embodiment of the
disclosed subject matter can be discussed herein or shown in the
drawings of the one embodiment and not in other embodiments, it
should be apparent that individual features of one embodiment can
be combined with one or more features of another embodiment or
features from a plurality of embodiments.
[0093] In addition to the various embodiments depicted and claimed,
the disclosed subject matter is also directed to other embodiments
having any other possible combination of the features disclosed and
claimed herein. As such, the particular features presented herein
can be combined with each other in other manners within the scope
of the disclosed subject matter such that the disclosed subject
matter includes any suitable combination of the features disclosed
herein. Furthermore, although reference is made to a stent
throughout this disclosure, other suitable devices and implants
likewise can be delivered using the catheter and system disclosed
herein. Thus, the foregoing description of specific embodiments of
the disclosed subject matter has been presented for purposes of
illustration and description. It is not intended to be exhaustive
or to limit the disclosed subject matter to those embodiments
disclosed.
[0094] It will be apparent to those skilled in the art that various
modifications and variations can be made in the method and system
of the disclosed subject matter without departing from the spirit
or scope of the disclosed subject matter. Thus, it is intended that
the disclosed subject matter include modifications and variations
that are within the scope of the appended claims and their
equivalents.
* * * * *