U.S. patent application number 13/452029 was filed with the patent office on 2012-11-22 for balloon visualization for traversing a tissue wall.
This patent application is currently assigned to HANSEN MEDICAL, INC.. Invention is credited to Daniel T. ADAMS, Frederic H. MOLL, Gregory J. STAHLER, Daniel T. WALLACE.
Application Number | 20120296161 13/452029 |
Document ID | / |
Family ID | 34915470 |
Filed Date | 2012-11-22 |
United States Patent
Application |
20120296161 |
Kind Code |
A1 |
WALLACE; Daniel T. ; et
al. |
November 22, 2012 |
BALLOON VISUALIZATION FOR TRAVERSING A TISSUE WALL
Abstract
Systems and methods for controllably traversing a tissue wall.
In one embodiment, a distal end of a catheter is positioned and/or
repositioned utilizing direct visualization out the distal end of
the catheter, as facilitated by an imaging element disposed within
the distal tip of the catheter. An inflatable balloon may comprise
a portion of the distal tip of the catheter for structural and/or
visualization media purposes. A tissue traversing element may be
forwarded through a working lumen defined by the catheter and
controllably pushed through a tissue wall as observed with the
imaging element. The tissue traversing element may comprise sensors
and the like to facilitate monitoring of changes in pressure,
color, oxygen saturation, flow rate, and echo timing, to determine
the position of the tissue traversing member relative to the tissue
wall.
Inventors: |
WALLACE; Daniel T.;
(Burlingame, CA) ; ADAMS; Daniel T.; (Palo Alto,
CA) ; MOLL; Frederic H.; (Woodside, CA) ;
STAHLER; Gregory J.; (San Jose, CA) |
Assignee: |
HANSEN MEDICAL, INC.
Mountain View
CA
|
Family ID: |
34915470 |
Appl. No.: |
13/452029 |
Filed: |
April 20, 2012 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
10949032 |
Sep 24, 2004 |
8172747 |
|
|
13452029 |
|
|
|
|
60506293 |
Sep 25, 2003 |
|
|
|
Current U.S.
Class: |
600/106 |
Current CPC
Class: |
A61B 1/00082 20130101;
A61B 5/0084 20130101; A61B 1/053 20130101 |
Class at
Publication: |
600/106 |
International
Class: |
A61B 1/018 20060101
A61B001/018; A61B 1/07 20060101 A61B001/07; A61B 1/06 20060101
A61B001/06; A61B 1/05 20060101 A61B001/05; A61B 1/12 20060101
A61B001/12 |
Claims
1. (canceled)
2. A method for traversing a tissue wall in a body, comprising:
endoluminally advancing a direct visualization elongate instrument
into a first cavity opposite a tissue wall from a second cavity,
wherein the elongate instrument comprises at its distal end an
imaging element and a component configured to provide a
substantially unobstructed field of view; approaching the tissue
wall with the elongate instrument; adjusting the relative
positioning between the distal end of the elongate instrument and
the tissue wall based upon direct visualization feedback; engaging
the tissue wall with the component, and providing a path to the
tissue wall with the lumen of the elongate instrument extending
through the component; controllably advancing a tissue traversing
member out of the lumen of the elongate instrument, through the
component, and through the tissue wall into the second cavity; and
upon traversing the tissue wall, confirming a position of the
traversing member in the second cavity using an imaging element or
sensing element positioned in the second cavity;
3. The method of claim 2, wherein approaching the tissue wall
comprises advancing the elongate instrument distal end to a
position adjacent the tissue wall with the elongate instrument
distal end in a contracted shape, and expanding the component into
an expanded shape such that a distal face of the component is
substantially normal to the longitudinal axis of the elongate
instrument to facilitate a larger direct visualization field of
view of the tissue wall.
4. The method of claim 2, wherein adjusting the relative
positioning comprises capturing images with an imaging element
positioned within an interior of the elongate instrument distal
end, the images representing one or both of structures located
immediately adjacent an exterior of the elongate instrument distal
end within a field of view of the imaging element, and structures
comprising the elongate instrument distal end within the field of
view of the imaging element.
5. The method of claim 2, wherein engaging the tissue wall
comprises advancing the elongate instrument toward the tissue wall
until contact is observed in the direct visualization feedback.
6. The method of claim 5, wherein engaging the tissue wall further
comprises ejecting saline between the elongate instrument distal
end and the tissue wall to displace blood or other fluids in order
to enhance visualization of the tissue wall.
7. The method of claim 2, wherein controllably advancing the tissue
traversing member comprises observing a relative positioning of the
tissue wall, the tissue traversing member, and the elongate
instrument distal end with direct visualization feedback.
8. The method of claim 2, wherein controllably advancing the tissue
traversing member comprises monitoring a variable selected from a
group consisting of pressure, color, oxygen saturation, flow rate,
and echo timing, in order to determine the position of the tissue
traversing member relative to the tissue wall.
9. The method of claim 2, wherein the tissue wall is an atrial
septum and approached from a right atrium, and wherein the tissue
traversing member is controllably advanced through the atrial
septum into a left atrium.
10. The method of claim 9, wherein adjusting the relative
positioning comprises locating the position of a fossa ovalis upon
the atrial septum.
11. The method of claim 2, where the traversing member further
includes a piercing tip and a traversing lumen, where the
traversing lumen provide access across the tissue wall after
withdrawing the elongate instrument away from the tissue wall.
12. The method of claim 11, further comprising advancing tools
through the traversing lumen.
13. The method of claim 2, wherein endoluminally advancing a direct
visualization elongate instrument comprises intravascularly
advancing a direct visualization elongate instrument.
14. The method of claim 2, wherein the component is a balloon.
15. A system to controllably traverse a tissue wall in a body,
comprising: an elongate tubular member having a distal end and
defining a working lumen; a component configured to provide a
substantially unobstructed field, of view coupled to the distal end
of the elongate tubular member, the component having a distal face
and a proximal end, where, when expanded the distal face is
substantially normal to the longitudinal axis of the working lumen;
a first imaging element disposed in an interior of the component or
at a distal end of the elongate tubular member or the component; a
lighting element disposed in the interior of the component or at a
distal end of the elongate tubular member or the component; a
tubular element defining a lumen between the distal end of the
component and a distal end of the working lumen of the elongate
tubular member; a tissue traversing element configured to advance
from a first cavity through and across a tissue wall into a second
cavity, wherein the tissue traversing element is disposed within
the working lumen of the elongate tubular member and positioned to
slidably extend through the working lumen and tubular element lumen
and beyond the component distal face within a field of view of the
first imaging element; and a sensing element or second imaging
element coupled to the tissue traversing member or to a sleeve
surrounding the tissue traversing member and configured for
detection in the second cavity to confirm a position of the
traversing member or the sleeve in the second cavity.
16. The system of claim 15, wherein the elongate tubular member
further defines at least one component sizing lumen to supply fluid
to expand the component.
17. The system of claim 15, wherein the elongate tubular member
further defines a lumen for transmitting light energy and image
data between one or more external devices and the respective
lighting and imaging elements.
18. The system of claim 15, wherein the first imaging element
comprises a charge-coupled device.
19. The system of claim 15, wherein the first imaging element
comprises an optical fiber.
20. The system of claim 15, wherein the lighting element comprises
a structure selected from the group consisting of an incandescent
light source, a light-emitting diode, and an optical fiber.
21. The system of claim 15, wherein the tissue traversing member
carries the sensing element which is configured to monitor a
variable selected from a group consisting of pressure, color,
oxygen saturation, flow rate, and echo timing.
22. The system of claim 15, wherein the first imaging element is
disposed adjacent the component proximal end.
23. The system of claim 15, wherein the first imaging element is
disposed adjacent the component distal end.
24. The system of claim 23, wherein a field of view of the first
imaging element does not include portions of the component.
25. The system of claim 15 wherein the distal end of the component
forms a concave surface out of which a field of view of the first
imaging element extends distally.
26. The system of claim 15, wherein the component is a balloon.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 10/949,032 filed on Sep. 24, 2004 which claims
the benefit of U.S. Provisional. Patent Application No. 60/506,293
filed Sep. 25, 2003, the contents of which are incorporated herein
by reference in their entirety.
BACKGROUND
[0002] One of the challenges in sending a medical device or portion
thereof across a an internal body tissue wall is ensuring that the
device is not advanced too far past the tissue wall, which can
damage adjacent tissue structures. The use of minimally invasive
surgical techniques, such as those employing catheters or other
elongate surgical probes, complicate this challenge by taking
certain aspects of a given medical procedure beyond the normal
field of view of the surgeon. For example, conventional minimally
invasive techniques for placing a trocar or needle across the
atrial septum of a heart involves pushing a transseptal needle,
such as those sold by Medtronic/AVE under the tradename
"Brockenbrough.TM.", out of a introducer sheath and across the
atrial septum, with guidance provided by a conventional imaging
modality, such as fluoroscopy.
[0003] While conventional techniques, such as "over-the-guidewire"
techniques, enable approximate positioning of a transseptal needle
adjacent a targeted location upon the atrial septum, there is still
no assurance that the needle is correctly positioned before
advancement through the tissue wall. Further, it is difficult
ascertaining whether the tip of the transseptal device been
advanced across the tissue wall and into an adjacent cavity, and
whether the cavity is, in fact, the targeted cavity.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] The invention is illustrated by way of example and is not
limited to the embodiments in the figures of the accompanying
drawings, in which like references indicate similar elements.
Further, features shown in the drawings are not intended to be
drawn to scale, nor are they intended to be shown in precise
positional relationship.
[0005] FIG. 1A depicts a side view of a catheter structure in
accordance with one embodiment of the invention.
[0006] FIG. 1B depicts a cross-sectional view of the structure of
FIG. 1A.
[0007] FIG. 1C depicts a cross-sectional view of a catheter
structure in accordance with another embodiment of the
invention.
[0008] FIG. 1D depicts a side view of a catheter structure in
accordance with yet another embodiment of the invention.
[0009] FIG. 1E depicts a side view of a catheter structure in
accordance with still another embodiment of the invention.
[0010] FIG. 1F depicts a side view of a catheter structure in
accordance with yet another embodiment of the invention.
[0011] FIG. 2 depicts a side view of a catheter structure in
accordance still another embodiment of the invention.
[0012] FIGS. 3A-3F are side views depicting various stages of yet
another catheter structure embodiment of the invention, including a
traversing member traversing a tissue wall in a body.
[0013] FIGS. 3G-3I are side views of a variation of the embodiment
of FIGS. 3A-F, in which sleeve is left positioned after withdrawal
of the tissue traversing member to function as an access lumen
across the tissue wall.
[0014] FIG. 4 is a side view depicting use of a catheter structure
embodiment similar to that depicted in FIG. 2.
[0015] FIGS. 5A-5N depict various structures for confirming a
position of a traversing member relative to a tissue wall in
accordance with various embodiments of the invention.
[0016] FIGS. 6A and 6B are flow charts illustrating two exemplary
procedures for traversing a tissue wall in accordance with
embodiments of the invention.
DETAILED DESCRIPTION
[0017] In the following detailed description of embodiments of the
invention, reference is made to the accompanying drawings in which
like references indicate similar elements. The illustrative
embodiments described herein are disclosed in sufficient detail to
enable those skilled in the art to practice the invention. The
following detailed description is therefore not to be taken in a
limiting sense, and the scope of the invention is to be defined and
limited only by the appended claims.
[0018] Referring to FIG. 1A, a side view of a distal portion (100)
of a catheter in accordance with the present invention is depicted.
The same structure is depicted in cross-sectional view in FIG. 1B.
In the depicted embodiment, a balloon (102) is disposed at the end
of an elongate tubular member (118) which defines various lumens
(120, 122, 124) and confines various structures (106, 112)
associated with balloon-based optical visualization. A working
lumen (124), defined in part by the elongate tubular member (118)
and in part by an associated tubular member (126), provides
continuous access down the longitudinal axis of the distal portion
(100) of the catheter. The tubular member (126) extends from the
elongate tubular member (118) to the distal end surface (104) of
the balloon, which in the depicted embodiment is substantially flat
with the balloon (102) in an inflated or expanded configuration
(128). The balloon (102), preferably comprising a translucent
polymeric material such as nylon and filled with saline (132) or
some other substantially translucent and biologically inert
low-viscosity fluid by inflation through one or more balloon sizing
lumens (120, 122), provides a medium through which an imaging
element (108) may capture images of the tubular member (126) and
adjacently positioned objects, such as tissue structures, which
fall within the field of view (114) of the imaging element. In
another embodiment, the balloon (102) may be inflated with carbon
dioxide or another relatively biologically inert gas.
[0019] The tubular member (126) also preferably comprises a
substantially translucent polymeric material, such as
polymethylmethacrylate ("PMMA") or polyimide, paired appropriately
with the imaging modality, to enable visualization into and across
the tubular member (126) with the imaging element (108). The
tubular member may comprise a separate tube component coupled to
the distal end of the elongate tubular member (118) utilizing
conventional techniques such as polymeric adhesive or stainless
steel clips, or may comprise an extension of the material
comprising the elongate tubular member (118).
[0020] The imaging element (108) may comprise a distal end of an
optical fiber, in which case the depicted image transmission line
(106) comprises an optical fiber, or it may comprise another image
capturing element, such as a charge-coupled-device (CCD) or
infrared imaging chip, in which case the image transmission line
(106) may comprise an electronic data transmission wire. A lighting
element (110) is paired with the imaging element to provide
illumination or radiation appropriate for capturing images in the
given tissue cavity. In the case of an optical fiber distal end as
an imaging element (108), the lighting element (110) preferably
comprises an emitter of light, such as a small light bulb, light
emitting diode, or end of another optical fiber distal end in
communication with an emitter or light. The light energy
transmission line (112) may comprise optical fiber, electronic lead
wire, or the like to transmit the appropriate lighting energy to
the lighting element (110). In another embodiment, the lighting
element (110) comprises an emitter of infrared-spectrum radiation
and the imaging element (108) comprises an infrared-detecting
imaging element to enable infrared-spectrum visualization within
the geometrically prescribed field of view (114). Suitable infrared
emitters and detectors are well known in the art and available from
suppliers such as CardioOptics of Boulder, Colo.
[0021] The imaging element (108) may comprise a lens, filter,
mirror, or other structure configured to control the field of view
(114) or focal length of the associated imaging element (108).
Further, a lens, filter, mirror, or other structure may be
positioned distally from the imaging element (108) within the
balloon portion (116) of the catheter distal end (100) for similar
purposes. The utilization of a imaging element (108) located at the
distal end of a medical instrument, such as a balloon catheter, for
purposes of visualizing objects from the point of interest is
referred to herein as "direct visualization". In other words,
"direct visualization" is used in reference to placing an imaging
"eye" distally to the location of tissue treatment interest.
[0022] Referring to FIG. 1B, a cross-sectional view of the
structures of FIG. 1A depicts the balloon sizing lumens (120, 122),
working lumen (124), imaging element (108), and lighting element
(110) in a substantially aligned configuration which is more
resistive to cantilever bending of the catheter distal end (100)
along the direction of the aligned configuration than in a
direction 90-degrees rotated from such alignment. In another
embodiment, as shown in FIG. 1C, such componentry is
cross-sectionally arranged as tightly as possible about the central
axis of the elongate tubular member (118) to facilitate easier and
more uniform cantilever bending. Such components may be arranged
within the elongate tubular member (118) to facilitate overall
mechanical performance goals given the mechanics of the components
themselves. For example, in an embodiment where high
cantilever-bending flexibility in all directions is desired, and
wherein the image transmission line (106) and light energy
transmission line (112) comprise relatively stiff optical fiber, it
is advantageous to position these two structures (106, 112) close
to the central axis of the elongate tubular member (118).
[0023] The elongate tubular member (118) preferably comprises a
conventional polymeric material, such as that sold under the trade
name "Pebax.TM." by Atofina Corporation, which is suitable for use
inside of animals and has desirable mechanical and manufacturing
properties. In the case of optical fiber, glass fibers, such as
those conventionally utilized in endoscopes, may be utilized, or
more flexible polymeric optical fibers, such as those available
from Nanoptics Corporation of Gainesville, Fla., may be
utilized.
[0024] FIG. 1D depicts a structure similar to that of FIG. 1A, with
the exception that the balloon (102) is in a deflated or contracted
configuration (130), as the result of a removal of saline (132)
from the balloon (102) via the balloon sizing lumens (120, 122). In
one embodiment, one of the balloon sizing lumens (120) is reserved
only for inflation, while the other (122) is reserved for
deflation. More or less than two balloon sizing lumens may be
suitable, depending upon the diameter of such structures and
desired rate of inflation and deflation, as would be apparent to
one skilled in the art. As shown in FIG. 1D, the contracted (130)
balloon preferably has an outer diameter roughly the same size as
the associated elongate tubular member (118) for atraumatic, smooth
endolumenal delivery while also facilitating a narrowed
forward-looking field of view (115) with the imaging element (108)
during delivery.
[0025] Referring to FIG. 1E, another embodiment is depicted wherein
the imaging element (108) is positioned forward within the balloon
(102) to gain better access to adjacent objects of interest
adjacent the distal end of the balloon (102) and within the field
of view (114) of the imaging element (108) and broadcast range of
the lighting element (110). With such a configuration the image
transmission line (106) extends beyond the distal end of the
elongate tubular member (118) and into the balloon (102), as
depicted in FIG. 1E. The portion of the image transmission line
(106) within the balloon (102) may be mechanically stabilized with
small polymer or metallic clips (134, 136), as shown.
[0026] Referring to FIG. 1F, another embodiment is depicted wherein
the lighting element (110) is positioned forward into the balloon
(102) with the imaging element (108) to minimize shadowing effects.
Mechanical stabilizers (138, 140) similar to those described in
reference to FIG. 1E may be utilized to maintain the relative
positioning of the balloon (102), tubular member (126), imaging
element (108), and lighting element (110).
[0027] Referring to FIG. 2, another embodiment is depicted wherein
the balloon (102) comprises a concave surface (144) distally upon
inflation, and wherein the imaging element (108) and lighting
element (110) are positioned for substantially immediate
visualization of adjacently positioned objects. With such a
configuration, it may be necessary or preferable to flush and fill
a volume defined by the concave surface (114) and an immediately
interfaced object with a translucent, high-viscosity, and
biologically inert fluid such as saline, or biologically inert gas,
utilizing additional fluid delivery lumens such as those depicted
(150, 152) in FIG. 2. Such lumens (150, 152) are extended through
the balloon (102) to the concave surface (144) by small tubular
members (154, 156), which may be stabilized along with the other
associated structures within the balloon (102) utilizing mechanical
stabilizers (146, 148) similar to those described in reference to
FIG. 1E, as shown in FIG. 2.
[0028] Referring to FIGS. 3A-3F, one embodiment of a method for
using structures such as those described in reference to FIGS.
1A-1F is depicted. Utilizing conventional techniques, the distal
end of the catheter (100) is positioned in the vicinity of a
targeted tissue structure or tissue wall (300). As shown in FIG.
3A, the distal end (100) may be advanced through a relatively tight
geometry between two tissue structures (306, 308) and into a first
enlarged cavity (302), which may be opposite the targeted tissue
wall (300) from a second enlarged cavity (304). A targeted region
of the tissue wall (300) may be identifiable by terrain or
substructures (310) comprising the surface of the targeted tissue
wall (300).
[0029] As the contracted (130) balloon (102) approaches the
substructures (310), a narrowed field of view (115) captured by the
imaging element (108) as facilitated by the lighting element (110)
may be utilized for navigating the balloon (102) into position
adjacent the tissue wall (300). In a substantially nontranslucent
media such as blood within the first cavity (302), visualization of
the substructures or tissue wall may not be useful until the distal
end of the balloon is very close to the tissue wall (300), whereas
in a more translucent media, such as saline or carbon dioxide,
targeted tissues and substructures may become visible as soon as
they are within a direct field of view, depending upon the focal
characteristics of the imaging element (108), as would be apparent
to one skilled in the art. Further, the translucent media within
the balloon (102) may comprise a contrast agent to facilitate
imaging. For example, in the case of a conventional fluoroscopic
imaging modality, the translucent media preferably comprises a
conventional contrast agent such as iodine.
[0030] Upon entry into a relatively large cavity (302), the balloon
may be inflated to provide a broadened field of view and
illumination, as shown in FIG. 3B. Positioning of the balloon (102)
relative to the first enlarged cavity (302) may be confirmed or
monitored using conventional techniques, such as ultrasound and
fluoroscopy.
[0031] Referring to FIG. 3C, the expanded balloon is advanced into
contact with the targeted tissue wall (300), where even with a
nontranslucent cavity (302) media such as blood, the tissue wall
(300) and substructures thereof (310) may be visualized through the
balloon (102) with the imaging element (108) and lighting element
(110). With such visualization, it may be preferable to fine-tune
the position of the balloon relative to the tissue wall (300).
[0032] Referring to FIG. 3D, a tissue traversing member, such as a
trocar or Brockenbrough.TM. needle, is advanced through the working
lumen (124) of the elongate tubular member (118) and tubular member
(126) to a position adjacent the targeted tissue wall (300). As
described in reference to FIGS. 1A and 1B, the tubular member (126)
preferably comprises a material through which the imaging element
(108) can "see" to provide the user with feedback regarding the
relative positioning of the traversing member (312), balloon (102),
and tissue wall (300). After confirmation of preferred alignment of
these structures, the traversing member (312) is advanced into and
across the tissue wall (300), as depicted in FIG. 3E. Visualization
of gradient markers (not shown) on the traversing member (312),
along with images of the pertinent structures from other
modalities, such as fluoroscopy and/or ultrasound, facilitate
precise positioning of a portion of the traversing member (312)
across and beyond (314) the subject tissue wall (300), into the
second cavity (304). Further details of the traversal positioning
and confirmation are described in reference to FIGS. 5A-5N. While
the illustrative description in reference FIGS. 3A-3E incorporates
a balloon catheter structure similar to that of FIG. 1A, such
description is applicable to embodiments such as those depicted in
FIGS. 1E and 1F and FIG. 2, with the exception that the structures
similar to FIG. 2 may involve additional steps, as further
described in reference to FIG. 4 and FIG. 6B.
[0033] Referring to FIG. 3F, subsequent to traversal and
confirmation of desired positioning of the traversing member (312),
the distal end of the catheter may be withdrawn, leaving behind the
(312). As depicted in FIG. 3G, in another embodiment, the
traversing member (312) is advanced into place accompanied with a
preferably tubular sleeve (500) which may be left in place along
with the traversing member (312) following withdrawal of the
catheter. Referring to FIGS. 3H and 3I, the traversing member (312)
may subsequently be withdrawn, leaving behind only the sleeve
(500), which provides an access lumen (501) over to the second
cavity (304), the access lumen being usable as a working lumen for
tools, injections, and the like which may be used to examine and
treat the second cavity (304), tissue wall (300), or other adjacent
tissues.
[0034] Referring to FIG. 4, a depiction of a catheter distal end
(101) similar to that depicted in FIG. 2 is illustrated in a
position analogous to the positioning of structures of FIG. 3C to
illustrate the notion that a flushing of substantially translucent
fluid (316) may be utilized to facilitate viewing by the imaging
element (108) and lighting element (110) through a volume (318)
captured between the concave surface (144) of the depicted
embodiment and a tissue wall (300).
[0035] Referring to FIG. 5A, a close-up side view depicting an
embodiment of a traversing member (312) positioned across a tissue
wall (300) is depicted. As shown in FIG. 5A, the traversing member
(312) is guided to the tissue wall (300) by the tubular member
(126). The distal tip (314) of the traversing member is positioned
in the cavity (304) opposite the cavity (302) in which the tubular
member (126) is positioned. Referring to FIG. 5B, a close-up side
view depicting an embodiment of a traversing member (312) with a
sleeve (500) is illustrated, with the sleeve (500) and traversing
member (312) both advanced into a position across the tissue wall
with distal protrusion (314) into the cavity (304) opposite the
cavity in which the tubular member (126) is positioned.
[0036] FIGS. 5C-5D, 5E-5F, 5G-5H, 5I-5J, 5K-5L, and 5M-5N depict
pairings of embodiments analogous to the sleeveless and sleeved
embodiments depicted in FIGS. 5A and 5B. Each of these pairings
features a different embodiment for confirming the position of a
traversing member (312) across a subject tissue wall (300) by
sensing or monitoring a difference known to be associated with a
desired second cavity (304) position or position within the
targeted tissue wall (300). For example, localized pressure within
a first cavity (302) may be substantially different than both the
localized pressure within the tissue wall (300) and within a second
cavity (304).
[0037] Likewise, for flow rate, oxygen saturation, etcetera, as
described in reference to FIGS. 5C-5N. Each of the different
monitoring variables is described separately in FIGS. 5C-5N, but,
as would be apparent to one skilled in the art, the monitoring
structures and modalities may be combined for increased position
determination capability. For example, in one embodiment it is
desirable to sense both pressure changes and echo timing for
redundancy in determining whether the distal tip (314) of a
traversing member (312) and/or sleeve (500) is within a first
cavity (302), tissue wall (300), second cavity (304), or perhaps an
undesirable location in a third cavity, such as a major blood
vessel with a substantially high flow rate as detected by Doppler
and distinguished from a targeted destination cavity.
[0038] Referring to FIG. 5C, the location of the traversing member
(312) may be determined by sampling fluid along a pathway (502)
through a lumen (317) formed in the traversing member (312), and
transporting sampled fluid proximally to a position outside of the
body for conventional testing, such as rapid chemical testing,
pulse oximetry, and the like. A traversing member (312) defining
such a lumen (317) could be formed using conventional technologies,
and purchased from suppliers of high-precision machined trocars and
similar structures such as Disposable Instrument Company, Inc. of
Shawnee Mission, Kans. FIG. 5D depicts a sleeved embodiment wherein
fluid is sampled along a pathway (504) between the traversing
member (312) and the sleeve (500). Referring back to FIG. 31, the
lumen (501) of an empty sleeve (500) may serve a similar
purpose.
[0039] Referring to FIG. 5E, a traversing member (312) having a
distally disposed pressure sensor (508) with a sensor lead (510)
may be utilized to monitor pressure changes at the distal portion
of the traversing member (312). Suitable small pressure sensors
(508) are known in the art and available from suppliers such as
Motorola Sensor Products of Phoenix, Ariz., and IC Sensors, a
division of Measurement Specialties, of Milpitas, Calif. FIG. 5F
depicts an embodiment wherein a pressure sensor (508) is coupled to
a sleeve (500).
[0040] Referring to FIG. 5G, a color shade sensor (512) is coupled
to the distal portion of a traversing member (312) to facilitate
monitoring of the color or graytone of local objects such as
aterial versus venous blood. The color shade sensor (512)
preferably comprises a CCD or CMOS-based image sensor, such as
those available from suppliers such as Eastman Kodak Image Sensor
Solutions, which is configured in this embodiment to transmit data
proximally through a sensor lead (514) as depicted. FIG. 5H depicts
an embodiment wherein a color shade sensor (512) is coupled to a
sleeve as opposed to directly to the traversing member (312). As
would be apparent to one skilled in the art, mirrors, lenses,
filters, and the like may be utilized to enhance or modify the
image sampling of such sensors.
[0041] Referring to FIG. 5I, an oxygen saturation sensor (516) is
coupled to the distal end of a traversing member (312) to
facilitate monitoring of the partial pressure of oxygen at the
oxygen saturation sensor (516) location utilizing a sensor lead
(518). As shown in FIG. 5J, an oxygen saturation sensor (516) may
also be positioned upon a sleeve (500). Small oxygen saturation
sensors, generally comprising a small radiation transmitter, such
as a laser diode, and a small radiation receiver, are available
from suppliers such as Nellcor Puritan Bennett of Pleasanton,
Calif.
[0042] Referring to FIG. 5K, an embodiment of a traversing member
is depicted with a flow sensor (520) disposed at the distal tip, in
a configuration selected to access flows straight ahead of the
advancing traversing member (312). FIG. 5L depicts a similar
embodiment with a flow sensor coupled to a sleeve (500). In each
embodiment, flow rate data is transmitted proximally, preferably
via a sensor lead (522). Small flow rate sensors, based upon
Doppler ultrasound or laser diode technology are well known in the
art and available from suppliers such as Transonic Systems, Inc. of
Ithaca, N.Y.
[0043] Referring to FIG. 5M, an embodiment of a traversing member
is depicted with an echo time sensor (524) disposed at the distal
tip, in a configuration selected to access flows straight ahead of
the advancing traversing member (312). FIG. 5N depicts a similar
embodiment with an echo time sensor (524) coupled to a sleeve
(500). In each embodiment, echo time data is transmitted
proximally, preferably via a sensor lead (526). An echo time sensor
(524), generally comprising a radiation emitter and detector
configured to detect the proximity of objects in a manner similar
to that of sonar technology, may be interfaced with a
computer-generated sound signal which changes frequency in
accordance with changes in echo time. With such a configuration,
for example, the sound frequency when the echo time sensor (524) is
positioned within a relatively high-density tissue wall (300) may
vary significantly from the sound frequency associated with a
relatively low density, open cavity (304), thereby facilitating
detection of the distal end of a traversing member (312) as it is
advanced across the tissue wall (300) and into the adjacent open
cavity (304).
[0044] Referring to FIG. 6A, an embodiment of a tissue wall
traversal process in accordance with the present invention is
summarized in flowchart format. Referring to FIG. 6A, a balloon
structure is positioned adjacent a tissue wall (530). Inflation of
the balloon optimizes visualization by providing a relatively
unobstructed field of view (532). Subsequent to confirming an
appropriate position upon the tissue wall or navigating to an
appropriate position utilizing visualization feedback (534), the
traversing member is advanced across the tissue wall while the
position is monitored for confirmation of appropriate positioning
(538). With the traversing member appropriately positioned across
the tissue wall, the balloon is deflated and retracted proximally
to leave the transecting member in place across the tissue wall
(540).
[0045] Referring to FIG. 6B, another embodiment of a tissue wall
traversal process in accordance with the present invention is
summarized in flowchart format, the embodiment of FIG. 6B differing
from that of FIG. 6A in that the embodiment of FIG. 6B comprises an
additional step of flushing a volume entrapped between a concave
balloon surface to provide better translucency for image capture,
in a process wherein a structure similar to that described in
reference to FIGS. 2 and 4 is utilized.
[0046] A process similar to that of FIG. 6A or 6B may be utilized,
for example, in a transseptal crossing procedure wherein safe
access to the left atrium of the heart is desired. Referring back
to FIG. 3A, in such an embodiment, tissue structures 306 and 308
may represent portions of the wall of a right atrium cavity (302),
the tissue wall (300) may represent the atrial septum, and the
second cavity (304) may represent the left atrium of the heart. In
accordance with the aforementioned techniques and structures, the
collapsed catheter distal end (100) may be advanced toward the
atrial septum, guided into position by wall (300) terrain (310)
such as the outline of the fossa ovalis.
[0047] Appropriate positioning of the working lumen (124) relative
to the outlines of the fossa ovalis may be confirmed utilizing
images from the imaging element (108) with a preferably fully
expanded (128) balloon (102) urged against the atrial septum,
subsequent to which a traversing member (312), such as a
Brockenbrough.TM. needle, may be advanced into the atrial septal
wall through the working lumen (124), as observed through the
tubular member (126), and preferably also through redundant
visualization modalities, such as ultrasound and/or fluoroscopy.
Further, the traversing member (312) may be instrumented with such
as a pressure, flow rate, color shade, or other sensor, to confirm
that the distal tip of the traversing member (312) is indeed where
the operator thinks it is.
[0048] Although the invention has been described herein with
reference to specific embodiments, many modifications therein will
readily occur to those of ordinary skill in the art without
departing from the inventive concepts taught herein. Accordingly,
all such variations and modifications are included within the
intended scope of the invention as defined by the following
claims.
* * * * *