U.S. patent application number 10/281017 was filed with the patent office on 2003-03-13 for prosthesis deployment device with translucent distal end.
Invention is credited to Borgmann, Doreen M., Getty, Heather L., Helgerson, Jeffrey A., Hemerick, James F., Raeder-Devens, Jennifer E., Schneider, Eric M., Shelso, Susan I., Sisombath, Kakao.
Application Number | 20030050686 10/281017 |
Document ID | / |
Family ID | 26832143 |
Filed Date | 2003-03-13 |
United States Patent
Application |
20030050686 |
Kind Code |
A1 |
Raeder-Devens, Jennifer E. ;
et al. |
March 13, 2003 |
Prosthesis deployment device with translucent distal end
Abstract
A prosthesis delivery and deployment device includes an elongate
and flexible outer catheter. The outer catheter has a tubular wall
of layered construction, including a translucent inner liner
running the complete catheter length, and three outer layers
including a translucent distal layer, an opaque medial layer and an
opaque proximal outer layer. The outer layers are adjacent one
another and are bonded to the liner. A braid composed of helically
wound metal filaments is disposed between the liner and the
proximal and medial outer layers, and includes a distal portion
between the liner and a proximal portion of the distal outer layer.
The liner and distal outer layer provide a translucent distal
region of the catheter that is adapted to constrain a radially
self-expanding prosthesis in a radially reduced, axially elongated
state. Because the stent constraining region is translucent, an
endoscope can be used to visually monitor the stent when so
constrained. Radiopaque markers can be mounted to the outer
catheter and to an inner catheter used to deploy the prosthesis, to
afford a combined visual and fluoroscopic monitoring for enhanced
accuracy in positioning the prosthesis, both before and during its
deployment.
Inventors: |
Raeder-Devens, Jennifer E.;
(St. Paul, MN) ; Shelso, Susan I.; (Plymouth,
MN) ; Hemerick, James F.; (Champlin, MN) ;
Schneider, Eric M.; (Minneapolis, MN) ; Getty,
Heather L.; (Plymouth, MN) ; Borgmann, Doreen M.;
(Hopkins, MN) ; Sisombath, Kakao; (Chanhassen,
MN) ; Helgerson, Jeffrey A.; (Minneapolis,
MN) |
Correspondence
Address: |
Frederick W. Niebuhr
Larkin, Hoffman, Daly & Lindgren, Ltd.
1500 Wells Fargo Plaza
7900 Xerxes Avenue South
Bloomington
MN
55431
US
|
Family ID: |
26832143 |
Appl. No.: |
10/281017 |
Filed: |
October 25, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10281017 |
Oct 25, 2002 |
|
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|
09569445 |
May 12, 2000 |
|
|
|
60134267 |
May 14, 1999 |
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Current U.S.
Class: |
623/1.11 |
Current CPC
Class: |
B32B 27/08 20130101;
A61F 2/02 20130101; B29C 66/712 20130101; B29C 66/1122 20130101;
B29C 66/5221 20130101; B32B 27/322 20130101; A61F 2/95 20130101;
Y10T 29/49826 20150115; A61F 2/966 20130101 |
Class at
Publication: |
623/1.11 |
International
Class: |
A61F 002/06 |
Claims
What is claimed is:
1. A prosthesis delivery and viewing device, including: an
elongate, flexible catheter having a tubular catheter wall defining
a catheter lumen, said catheter body along a distal end region
thereof being adapted to substantially surround a body insertable
prosthesis and thereby releasably retain the prosthesis within the
catheter lumen; wherein the catheter wall, at least along the
distal end region, is translucent to allow an optical viewing of
the body insertable prosthesis through the catheter wall when the
prosthesis is so retained.
2. The device of claim 1 further including: a prosthesis release
component mounted movably with respect to the catheter to effect a
release of the prosthesis from within the catheter lumen.
3. The device of claim 2 wherein: the prosthesis release component
includes an elongate, flexible member disposed inside the catheter
lumen and adapted to move the prosthesis distally relative to the
catheter to effect the release.
4. The device of claim 3 wherein: a distal end of the flexible
member is disposed proximally of the prosthesis when the prosthesis
is so retained.
5. The device of claim 3 wherein: the flexible member has a distal
end portion surrounded by the prosthesis when the prosthesis is so
retained.
6. The device of claim 1 wherein: the prosthesis is radially
self-expanding, and when so retained is confined in a radially
compressed state.
7. The prosthesis of claim 1 further including: an optical viewing
device positionable proximate the distal end of the catheter to
facilitate said optical viewing.
8. The device of claim 1 wherein: the catheter wall is more
flexible along the distal end region as compared to a remaining
portion of the catheter disposed proximally of the distal end
region.
9. The device of claim 1 wherein: the catheter wall is translucent
substantially over an entire length of the catheter.
10. The device of claim 1 wherein: a remaining portion of the
catheter disposed proximally of the distal end region is
opaque.
11. The device of claim 1 further including: a metal reinforcing
structure integral with the catheter wall, at least along a
remaining portion of the catheter wall disposed proximally of the
distal end region.
12. The device of claim 1 wherein: the catheter wall includes a
translucent inner tubular layer, a translucent first outer tubular
layer surrounding the inner tubular layer along a distal end
portion of the inner tubular layer, and a second outer tubular
layer surrounding the inner tubular layer and disposed proximally
of the first outer tubular layer.
13. The device of claim 12 wherein: the second outer tubular layer
is opaque.
14. The device of claim 12 wherein: the first outer tubular layer
is more flexible than the second outer tubular layer.
15. The device of claim 12 further including: a radiopaque marker
disposed near a distal end of the catheter wall and between the
inner tubular layer and the first outer tubular layer.
16. The device of claim 12 further including: a metal reinforcing
structure disposed between the inner tubular layer and the second
outer tubular layer.
17. The device of claim 16 wherein: the metallic reinforcing
structure includes a plurality of helically wound and interbraided
filaments.
18. A catheter for deploying a body insertable prosthesis,
including: an elongate, flexible, translucent inner tubular body; a
flexible, translucent first outer tube surrounding and integral
with a distal end region of the inner tubular body; and an
elongate, flexible second outer tube surrounding the inner tubular
body, integral with the inner tubular body, and disposed proximally
of the first outer tube.
19. The catheter of claim 18 further including: a flexible third
outer tube disposed between, and in contact with, the first outer
tube and the second outer tube.
20. The catheter of claim 18 wherein: the second outer tube is
opaque.
21. The catheter of claim 18 further including: a radiopaque marker
disposed between the inner tubular body and the first outer tube,
and further disposed proximate respective distal ends of the inner
tubular body and the first outer tube.
22. The catheter of claim 18 including: a reinforcing structure
disposed between the inner tubular body and the second outer
tube.
23. The catheter of claim 22 wherein: said reinforcing structure
further is disposed between the inner tubular body and a proximal
portion of the first outer tube.
24. The catheter of claim 22 wherein: the reinforcing structure
comprises helically wound metal filaments interbraided with one
another.
25. The catheter of claim 18 wherein: the first outer tube is more
flexible than the second outer tube.
26. The catheter of claim 18 further including: a radially
self-expanding prosthesis disposed within the inner tubular body,
in substantial axial alignment with the first outer tube, and
constrained in a radially compressed state.
27. The catheter of claim 18 further including: a prosthesis
release component mounted movably relative to the inner tubular
body.
28. The device of claim 27 wherein: the prosthesis release
component includes an elongate, flexible member contained inside
the inner tubular body.
29. A process for deploying a radially self-expanding prosthesis
within a body lumen, including: disposing a radially self-expanding
prosthesis in a radially compressed state within a catheter,
surrounded by a tubular wall of the catheter along a distal end
region of the catheter; moving the catheter intraluminally to
position the distal end region of the catheter near a selected
prosthesis deployment site within a body lumen; with the catheter
distal end region so positioned, initiating a release of the
prosthesis from the catheter, and during said release, using an
optical viewing device to optically view at least a proximal
portion of the prosthesis through the catheter wall, to visually
monitor a location of the prosthesis; and after completing the
release of the prosthesis, proximally withdrawing the catheter to
leave the prosthesis disposed within the body lumen.
30. The process of claim 29 wherein: the initiating of the release
of the prosthesis comprises positioning an elongate prosthesis
release member in contact with the prosthesis, and moving the
tubular catheter proximally while using the release member to
substantially prevent the prosthesis from moving proximally with
the catheter.
31. The process of claim 30 further including: while visually
monitoring a location of the prosthesis, further monitoring a
position of the elongate prosthesis release member relative to the
catheter.
32. The process of claim 29 further including: before initiating a
release of the prosthesis, using a visible indicium on the tubular
catheter to approximate a location of the proximal portion of the
prosthesis with respect to the body lumen.
33. A prosthesis delivery and deployment catheter, including: an
elongate, flexible inner tubular body; a flexible first outer tube
surrounding and integral with a distal end region of the inner
tubular body; and an elongate, flexible second outer tube
surrounding the inner tubular body, integral with the inner tubular
body, and disposed proximally of the first outer tube; wherein the
first outer tube is more flexible than the second outer tube, and
extends axially less than one-fourth of the length of the inner
tubular body, and wherein the second outer tube extends axially at
least three-fourths of the length of the inner tubular body.
34. The catheter of claim 33 wherein: the second outer tube has a
durometer hardness greater than that of the first outer tube.
35. The catheter of claim 33 further including: a flexible third
outer tube disposed between, and in contact with, the first outer
tube and the second outer tube.
36. The catheter of claim 35 wherein: the second outer tube and the
third outer tube are opaque, and the inner tubular body and the
first outer tubing are translucent.
Description
[0001] This application claims the benefit of priority of
Provisional Application No. 60/134,267 entitled "Translucent
Medical Device," filed May 14, 1999.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to medical devices for
delivering endoprostheses to predetermined treatment sites within
body cavities or lumens, and further deploying the endoprostheses
at the selected sites. More particularly, this invention relates to
such devices that are capable of enabling or facilitating a
tracking of the endoprostheses during deployment.
[0003] A variety of patient treatment and diagnostic procedures
involve the use of prostheses inserted into the body of a patient
and intraluminally implanted. Percutaneous translumenal coronary
angioplasty (PTCA) and other vascular treatments frequently involve
implanting prostheses such as stents to maintain vessel patency or
grafts to shunt blood. Similar implantations are used in
non-vascular procedures, e.g., enteral, billiary, and esophageal
applications.
[0004] There is a need to accurately characterize the intended
implant site to facilitate proper placement of the prosthesis.
There is a further need, just before deployment and during
deployment, to ascertain the location of the prosthesis relative to
the intended placement site. One known approach to such
characterizing and monitoring is angiography, which involves
supplying a radiopaque contrast fluid to the cavity or lumen, then
radiographically viewing the lumen. This approach, however,
provides only a monochromatic, two-dimensional image showing a
profile but no depth of field.
[0005] According to another approach, radiopaque markers can be
placed on the delivery/deployment device. Before deployment, the
position of the prosthesis within the device is known, and
determining the device position in effect accurately determines the
prosthesis position. This advantage is lost during deployment,
however, and again the image offers neither distinctions in color
nor depth of field.
[0006] According to yet another approach, the prosthesis can be
fabricated at least in part using a radiopaque material. For
example, the filaments of a stent can be formed of, or may
incorporate a core formed of, platinum, tantalum or another
radiopaque material. This approach likewise lacks the capacity for
distinction among colors, and imposes limitations upon the
materials used to form the prosthesis.
[0007] U.S. Pat. No. 5,411,016 discloses an intravascular balloon
catheter having a lumen containing an angioscope. A distal portion
of the catheter shaft, surrounded by the dilatation balloon, is
transparent, and index markers are provided along the balloon.
Thus, objects against which the balloon wall is pressed when the
balloon is inflated can be quantified. This structure requires
viewing the lumen through the catheter wall and the balloon wall,
and does not address the need for monitoring the position of a
prosthesis with respect to its delivery device during deployment.
This need is particularly apparent in connection with radially
self-expanding prostheses, which are constrained in radially
reduced configurations during delivery, and must be released from
their confining devices during deployment to permit radial
self-expansion.
[0008] Therefore, it is an object of the present invention to
provide a prosthesis delivery and deployment device that
substantially surrounds a prosthesis to retain the prosthesis
during delivery to a treatment site, yet facilitates an optical
viewing of the prosthesis before and during its deployment.
[0009] Another object is to provide a prosthesis delivery device
particularly well suited to negotiate tortuous intraluminal
pathways in the body, that incorporates a translucent carrier
segment through which a prosthesis carried within the device can be
optically viewed.
[0010] A further object is to provide a process for deploying a
radially self-expanding prosthesis within a body lumen in which an
optical viewing device is advantageously used to view at least a
proximal portion of the prosthesis to visually monitor a location
of the prosthesis during its deployment.
[0011] Yet another object is to provide a catheter or other device
for intraluminal delivery of a prosthesis, that incorporates a
prosthesis confining wall sufficiently light transmissive to enable
a viewing of the prosthesis through the wall, so that an optical
instrument positioned within a body lumen outside the catheter can
be used to observe the prosthesis contained in the delivery device,
as well as tissue surrounding the delivery device.
SUMMARY OF THE INVENTION
[0012] To achieve these and other objects, there is provided a
prosthesis delivery and viewing device. The device includes an
elongate, flexible catheter having a tubular catheter wall defining
a catheter lumen. The catheter, along a distal end region thereof,
is adapted to substantially surround a body insertable prosthesis
and thereby releasably retain the prosthesis within the catheter
lumen. The catheter wall, at least along the distal end region, is
translucent to allow an optical viewing of the body insertable
prosthesis through the catheter wall when the prosthesis is so
retained.
[0013] Most preferably, the distal end region of the wall is
substantially transparent, i.e., highly transmissive of wavelengths
in the visible spectrum. Satisfactory viewing is achieved, if the
distal end region wall merely is translucent; more particularly,
sufficiently light transmissive so that at least about 25% of light
impinging directly upon one side of the catheter wall is
transmitted through the wall to the other side. A polyether block
amide, for example as sold under the brand name Pebax, has been
found to be well suited as a catheter wall material, not only due
to its relative transparency, but also because it provides a
ductile or flexible catheter wall that bonds well with other
polymeric material. Certain nylons also can be used, although they
are not as ductile as the Pebax material.
[0014] The device is advantageously used as part of a system that
also includes an optical viewing device positionable proximate the
distal end of the catheter to facilitate an optical viewing of the
prosthesis and surrounding body lumen or cavity. An endoscope is
suitable as such a viewing device.
[0015] According to one particularly preferred construction, the
catheter includes an elongate, flexible translucent inner tubular
body. A flexible, translucent first outer tube surrounds and is
integral with a distal end region of the inner tubular body. An
elongate, flexible second outer tube surrounds the inner tubular
body, is integral with the inner tubular body, and is disposed
proximally of the first outer tube. If desired, a flexible third
outer tube is disposed between the first and second outer tubes,
and contacts the other outer tubes to provide a substantially
continuous profile composed of the three outer tubes. This
construction allows a tailoring of the catheter, to provide a
balance between two somewhat conflicting needs: sufficient
flexibility to negotiate serpentine pathways; and sufficient
columnar strength along the catheter length to provide the
necessary axial pushing force.
[0016] In particular, such tailoring can involve selecting
materials of different durometer hardness for the outer tubes. One
highly preferred example uses a 63 Shore D durometer Pebax material
in the first outer tube, and a 72 Shore D durometer Pebax material
in the second, proximal outer tube which comprises most of the
catheter length. To provide further columnar strength and
resistance to kinking, a support structure can be interposed
between the inner tubular layer and at least the second outer tube.
A preferred structure is a braid of helically wound metal
filaments, e.g., stainless steel or a cobalt-based alloy such as
that sold under the brand name Elgiloy. If desired, the wire braid
can extend distally beyond the second outer tube, and thus reside
between the inner tubular layer and a proximal portion of the first
outer tube, up to about one-half of the first outer tube length.
When a third, medial outer tube is employed, it is preferably
composed of a material having a 63 Shore D durometer hardness.
[0017] The delivery device further can include a prosthesis release
component mounted moveably with respect to the catheter to effect a
release of the prosthesis from within the catheter lumen. For
example, an elongate flexible member, which can be a tube if
desired, is disposed inside the catheter lumen and either abuts the
proximal end of the prosthesis, or is surrounded by the prosthesis
along its distal portion. In many cases the latter arrangement is
more desirable, because it enables a retraction of the prosthesis
after it is partially deployed, if repositioning is deemed
necessary.
[0018] The delivery device is particularly well suited for use in a
process for deploying a radially self-expanding prosthesis within a
body lumen, including:
[0019] a. disposing a radially self-expanding prosthesis in a
radially compressed state within a catheter, surrounded by a
tubular wall of the catheter along a distal end region of the
catheter;
[0020] b. moving the catheter intraluminally to position the distal
end region of the catheter near a selected prosthesis deployment
site within a body lumen;
[0021] c. with the catheter distal end region so positioned,
initiating a release of the prosthesis from the catheter, and
during the release, using an optical viewing device to optically
view at least a proximal portion of the prosthesis through the
catheter wall, to visually monitor a location of the prosthesis;
and
[0022] d. after completing the release of the prosthesis,
proximally withdrawing the catheter to leave the prosthesis
disposed within the body lumen.
[0023] Thus in accordance with the present invention, a prosthesis
can be optically viewed both before its release to insure an
accurate positioning within a body lumen, and during its release to
monitor its position both with respect to the lumen, and with
respect to the delivery/deployment catheter. An endoscope or other
suitable optical device can provide an image that enables the user
to distinguish among colors, which can be beneficial in recognizing
properties of the tissue at the treatment site. Optical images also
afford depth of field. The capability of optically viewing the
lumen and prosthesis when still contained within the catheter,
combined with fluoroscopic imaging of the catheter and the
prosthesis, provides particularly effective monitoring of the
deployment and positioning of the prosthesis.
[0024] In the Drawings
[0025] For a further understanding of the above and other features
and advantages, reference is made to the following detailed
description and to the drawings, in which:
[0026] FIG. 1 is a side elevation of a prosthesis delivery and
deployment device constructed in accordance with the present
invention;
[0027] FIG. 2 is an enlarged elevation, partially sectioned to show
further features of the device;
[0028] FIGS. 3, 4, 5 and 6 are sectional views taken respectively
along the lines 3-3, 4-4, 5-5, and 6-6 in FIG. 1;
[0029] FIG. 7 is a schematic view of a prosthesis deployment and
viewing system incorporating the deployment device;
[0030] FIG. 8 is a side elevation illustrating an alternative
embodiment deployment device; and
[0031] FIG. 9 is a side elevation illustrating another alternative
embodiment deployment device.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0032] Turning now to the drawings, there is shown a device 16 for
delivering a radially self-expanding prosthesis to a selected
treatment site within a body cavity or body lumen, and for
deploying the prosthesis, once it is positioned at the treatment
site. The device includes an elongate, flexible outer catheter 18
having a tubular catheter wall 20. A radiopaque marker 22 is
mounted to the catheter near its distal end 24.
[0033] Along its axial length, catheter wall 20 is divided into
three sections or regions: a distal region 26; a medial region or
transition region 28; and a proximal region 30. As indicated by the
break, the full length of proximal region 30 is not shown in FIG.
1. The proximal region is by far the longest of the three regions.
The diameter and axial length of catheter 18 can vary according to
the application and size of the body lumen involved. Some typical
ranges for enteral applications include a total catheter length of
135-230 cm in conjunction with a distal segment length of 7-18.5
cm, a transition region length of 6-7.5 cm, and a diameter of 5-22
French, i.e. about 1.7-3.0 mm.
[0034] Distal region 26 extends from distal end 24 to a junction 32
between two slightly different polymeric materials employed in
forming the catheter wall. Along the distal region, the catheter
wall preferably is transparent, exhibiting a high transmissivity of
energy in the visible spectrum. Less preferably but satisfactorily,
catheter wall 20 is translucent along the distal region, in the
sense that at least 25% of the energy in the visible spectrum
impinging directly upon catheter 18 is transmitted through catheter
wall 20 to the other side. A braid 34 formed of helically wound
intersecting filaments of stainless steel, a cobalt-based alloy or
other suitable metal, forms a layer of catheter wall 20 beginning
at a distal region that is visible due to the transparency of the
polymeric layer surrounding it. The braid extends proximally to a
proximal end 36 of the catheter, provides a reinforcing structure
that increases the columnar strength of medial region 28 and
proximal region 30, and also increases radial stability and
resistance to kinking when catheter 18 is bent.
[0035] FIG. 2 shows device 16, particularly the distal and medial
sections, in greater detail. Outer catheter 18 includes a catheter
lumen 38 that runs substantially the entire catheter length. An
inner catheter 40, contained in lumen 38, is movable axially
relative to outer catheter 18. Inner catheter 40 extends lengthwise
substantially along the entire length of the outer catheter. A
sleeve 42 surrounds inner catheter 40 along a distal portion of the
catheter comparable to catheter distal region 26 in its axial
length. A prosthesis, in particular a radially self-expanding stent
44, surrounds the inner catheter and sleeve along the distal
portion of the inner catheter. Stent 44 in turn is surrounded by
the distal region of outer catheter 18, constrained by the outer
catheter wall in a radially reduced, axially elongated state. Stent
44 is radially self-expanding, in that once free of the outer
catheter, the stent tends to shorten axially and expand radially to
a normal or unstressed shape in which the stent diameter is much
larger than the diameter of the outer catheter. Stent 44 is
somewhat similar to braid 34, in that the stent is composed of
oppositely directed helically wound filaments or wires that
intersect one another. However, because the filaments forming stent
44 typically are smaller in diameter than the filaments forming
braid 34, the filaments of the stent frequently are formed of
materials selected for enhanced radiopacity, e.g. a composite
construction including a tantalum core within an Elgiloy casing. A
radiopaque marker 45 is located along inner catheter 40, between
the inner catheter and the sleeve.
[0036] The layered, segmented construction of catheter wall 20 is
best seen in FIG. 2. Catheter wall 20 includes an inner layer, i.e.
a PTFE liner 46 that extends for the length of the catheter. Liner
46 is substantially translucent to transparent, typically with an
amber cast. Liner 46 typically is etched to improve bonding
adhesion to the layers that surround it.
[0037] The surrounding layers, or outer tubes, include a
transparent or translucent outer distal layer 48, an opaque outer
medial layer 50, and an opaque outer proximal layer 52. Marker 22
is disposed between liner 46 and distal outer layer 48. Beginning
near the proximal end of outer layer 48 and extending proximally
for the remainder of the catheter length, braid 34 is interposed
between outer layer 48, medial outer layer 50 and proximal outer
layer 52. The outer layers are bonded to the liner. Consequently,
the liner, outer layers, marker and braid are integral with one
another.
[0038] In accordance with the present invention, materials are
selected for the liner and outer layers to impart desired
properties that differ over the length of catheter 18. As noted
above, liner 46 is formed of PTFE. The inside surface of liner 46
preferably is coated with silicone, to provide a low-friction
surface to contact stent 44 and facilitate axial travel of inner
catheter 40 relative to the outer catheter. Liner 46 is
cylindrical, and can have for example an inner diameter of 0.117
inches and a radial thickness of 0.0015 inches.
[0039] Over the majority of the catheter length, the next radially
outward layer is composed of braid 34. The filaments of braid 34
can be stainless steel wires, having a diameter of about 0.015
inches. In one advantageous arrangement, 32 wires are wound
helically, interbraided in a two-over-two-under pattern, at about
52 pics per inch. The braid angle can be 110-150 degrees, i.e.
55-75 degree inclines from a longitudinal axis.
[0040] At the distal end of catheter 18, radiopaque marker 22 is
provided in the form of an annular band surrounding liner 46. The
band can be formed of a platinum/iridium alloy, and can have a
diameter of 0.127 inches and radial thickness of about 0.0015
inches.
[0041] Distal outer layer 48 surrounds and is bonded to liner 46.
The preferred material for the distal outer layer is a polyether
block amide available under the brand name "Pebax," with a 63 Shore
D durometer hardness. Outer layer 48 is substantially transparent.
Accordingly, liner 46 and outer layer 48 in combination provide a
catheter wall region that is substantially transparent, or at least
sufficiently translucent so that stent 44, when contained within
catheter 18 as shown in FIG. 2, is visible from outside the
catheter through the catheter wall. Another favorable property of
outer layer 48 is its relatively high flexibility, whereby the
distal region is well suited for initial tracking through
serpentine body passages as the catheter is moved toward an
intended treatment site. Distal outer layer 48 can have a diameter
of about 1.17 inches, and a thickness of about 0.010 inches.
[0042] Medial outer layer 50 also is preferably constructed of the
Pebax polyether block amide, having the same 63 Shore D durometer
hardness. The polymer is combined with a blue dye, and thus forms
an opaque layer. Outer layer 50 can have an axial length of about 5
cm, an inner diameter of about 0.129 inches, and a radial thickness
of about 0.012 inches. Due to the contrast between the translucent
outer layer 48 and the opaque outer layer 50, junction 32 provides
a clear visible marker that locates the proximal end of stent 44
when the stent is radially constrained by the outer catheter.
[0043] Transition region 28 includes the full length of outer layer
50, and in addition the length of braid 34 extending distally into
distal region 26. Although the visible distal extension of the
braid can include half the length of distal region 26 and even more
if desired, this extension typically is in the range of 1-2.5 cm.
The transition region thus combines braid 34 and the 63 D durometer
hardness Pebax polymer, with part of the polymer being translucent
and part being opaque. Transition region 28 is flexible, although
less flexible than the distal region. The braid reduces kink
potential.
[0044] Proximal outer layer 52 is formed of a Pebax polymer having
a 72 Shore D durometer hardness. The proximal outer layer can have
an inner diameter of 0.129 inches and a radial thickness of 0.012
inches, same as the medial outer layer. Also like the medial layer,
proximal outer layer 52 is combined with a blue dye to render this
region of the catheter opaque. The higher durometer hardness of the
proximal outer layer provides enhanced column strength, thus to
provide the axial pushing force necessary for advancing the
catheter distally through body passages.
[0045] Less highly preferred but satisfactory results may be
achieved when forming the various catheter wall components using
alternative materials. For example, several grades of nylon
including nylon 12 may be used to form outer layers 48, 50 and 52.
A suitable alternative material for liner 46 is polyurethane, e.g.
as available under the brand name Pellethane. A nylon available
under the brand name Arnitel is suitable for the outer layers,
although better suited for the opaque outer layers than translucent
outer layer 48.
[0046] Inner catheter 40 is preferably formed of polyether ether
ketone (PEEK). The polymer forming sleeve 42 preferably is
substantially softer and more flexible than the other polymers, so
that stent 44 when disposed between the catheters as shown in FIG.
2 tends to embed itself into the sleeve.
[0047] FIG. 7 illustrates a system 54, including device 16, for
delivering and deploying stent 44 within a body lumen 56. The
system includes an endoscope 58 positionable within body lumen 56
proximate distal region 26 of the catheter. Although the endoscope
is represented schematically, it is to be understood that the
endoscope can incorporate a light source 60, an optical fiber or
other suitable optical path to transmit light to the distal end of
the endoscope, an optical fiber, bundle of fibers or other suitable
path to transmit images proximally along the endoscope, and a
display terminal 62 for displaying the visible image. The proximal
end of outer catheter 18 is coupled to a manifold 64. A handle 66,
coupled to inner catheter 40 and movable relative to the manifold,
controls axial movement of the inner catheter relative to the outer
catheter. Additional fittings 68 are provided for a variety of
purposes depending on the procedure, potentially including
accommodating a guidewire, transmitting a therapeutic drug to the
distal end of the catheter, and accommodating a balloon inflation
fluid for a dilatation balloon.
[0048] System 54 is used in a stent implant procedure as follows.
First, a guidewire or guide canula is used to track endoscope 58 to
the selected implant site. Likewise, a guidewire (not shown) is
tracked to the site.
[0049] Next, device 16 is loaded onto the guidewire and tracked to
the site. The flexibility of the distal section improves cornering
through the body passages on the way to the site. Meanwhile,
proximal region 30 provides the column strength necessary to push
the device toward the site. Braid 34 provides resistance to
kinking, combined with the ability to track tight radii.
[0050] As distal end 24 of the device approaches the treatment
site, junction 32 between translucent and opaque regions provides a
reliable visible indication to locate the proximal end of the
constrained stent 44.
[0051] Once the catheter distal end is positioned as desired, stent
44 is deployed, by pulling outer catheter 18 proximally while
controlling handle 66 to maintain inner catheter 40 in place. Due
to the softness of sleeve 42 and the lubricity of silicone coated
liner 46, stent 44 tends to remain with the inner catheter rather
than moving proximally with the outer catheter.
[0052] As the outer catheter continues to move proximally, distal
end 24 is carried proximally with respect to the distal end of the
stent, thus partially freeing the stent for radial self-expansion.
Because of the translucency of the outer catheter wall along distal
end region 26, endoscope 58 can be used continuously during
deployment to monitor the position of stent 44, relative to body
lumen 56 and relative to inner catheter 40. Moreover, as outer
catheter 18 continues to move axially relative to inner catheter
40, radiopaque marker 22 likewise moves axially relative to marker
45, thus to permit a fluoroscopic monitoring of the outer catheter
axial position relative to the inner catheter. Markers 22 and 45
can be positioned such that as marker 22 approaches marker 45, a
limit approaches beyond which deployment cannot be reversed, i.e.
when the stent no longer can be drawn back into outer catheter 18
by advancing the outer catheter distally relative to the inner
catheter. The combined visual and fluoroscopic monitoring enables
the user to more precisely confirm an appropriate positioning of
the stent before exceeding the limit.
[0053] Beyond the limit, outer catheter 18 is moved proximately
until stent 44 is completely free of the outer catheter. This
leaves the stent free to radially self-expand to its nominal
diameter. The nominal diameter typically exceeds a diameter of body
lumen 56, so that the stent self-expands into an intimate contact
with a tissue wall 70 defining the body lumen. With the implant of
the stent thus complete, endoscope 58 and device 16 are proximally
withdrawn, leaving the stent implanted at the treatment site.
[0054] FIG. 8 illustrates a portion of an alternative embodiment
outer catheter 72 including a single liner 74 and several outer
layers including a distal outer layer 76, medial outer layer 78 and
proximal outer layer 80 as before. Outer catheter 72 differs from
outer catheter 18, in that all three of the outer layers are
translucent or substantially transparent, providing an outer
catheter that is translucent or substantially transparent over its
entire length.
[0055] FIG. 9 illustrates an outer catheter 82 of another
alternative embodiment device, including an inner liner 84 and a
single outer layer 86 running substantially the entire outer
catheter length. A body implantable stent 88 is constrained along
the distal region of the outer catheter, in a radially reduced
axially elongated state. An inner catheter 90 is contained within a
lumen 92 of the outer catheter. Rather than being surrounded by the
stent, inner catheter 90 is disposed proximally of the stent, and
movable distally relative to the outer catheter to engage the
proximal end of the stent. Catheter 90 deploys the stent by pushing
the stent distally relative to catheter 82. While this approach is
suitable for certain procedures, and may reduce the cost of the
device, it also lacks the capability of reversing stent deployment
to reposition the stent.
[0056] Thus, in accordance with the present invention, a prosthesis
can be visually monitored during its deployment, even when
substantially or entirely contained within the deployment catheter.
When provided with layers of differing flexibility over the
catheter length, the catheter can be sufficiently flexible at its
distal end for efficient tracking, yet sufficiently rigid along its
more proximal regions to insure adequate distal pushing force.
Further, radiopaque markers can be employed to enable fluoroscopic
monitoring of device components as well as visual monitoring of the
device and stent, to insure that the stent not only is properly
aligned at the outset of deployment, but remains in the desired
position as it is released from the deployment device.
* * * * *