U.S. patent number 4,875,897 [Application Number 07/180,728] was granted by the patent office on 1989-10-24 for catheter assembly.
This patent grant is currently assigned to Regents of University of California. Invention is credited to Garrett Lee.
United States Patent |
4,875,897 |
Lee |
October 24, 1989 |
**Please see images for:
( Certificate of Correction ) ** |
Catheter assembly
Abstract
A catheter assembly including a first catheter having distal and
proximal ends, and a second catheter which is positionable within
the first catheter. The second catheter has a smaller diameter and
is more flexible than the first catheter. The second catheter is
positionable within the first catheter so that its distal end is
extendable beyond the distal end of the first catheter. An
expandable balloon or inflatable means is affixed to the outer
surface of either the first or second catheters near the distal end
thereof. When inflated, the inflatable means sealingly engages the
interior walls of a body channel into which the catheter assembly
has been inserted. The catheter assembly may also include
associated fiber optics for viewing and removing obstructions.
Inventors: |
Lee; Garrett (Sacramento
County, CA) |
Assignee: |
Regents of University of
California (Berkeley, CA)
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Family
ID: |
27370520 |
Appl.
No.: |
07/180,728 |
Filed: |
April 6, 1988 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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63699 |
Jun 12, 1981 |
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913639 |
Sep 30, 1986 |
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778278 |
Sep 18, 1985 |
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326221 |
Dec 1, 1981 |
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Current U.S.
Class: |
604/536; 606/7;
606/15; 604/28; 606/17 |
Current CPC
Class: |
A61B
1/0053 (20130101); A61B 18/245 (20130101); A61M
25/0026 (20130101); G02B 6/4296 (20130101); A61B
2017/22051 (20130101); A61B 2017/22055 (20130101); A61M
25/0155 (20130101); A61M 2025/0079 (20130101) |
Current International
Class: |
A61B
18/20 (20060101); A61B 18/24 (20060101); A61B
1/005 (20060101); A61M 25/00 (20060101); G02B
6/42 (20060101); A61B 17/22 (20060101); A61M
25/01 (20060101); A61M 025/00 () |
Field of
Search: |
;604/283,164,165,20-22,27,28,35-38,43,53,96,101
;128/303.1,DIG.9 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Yasko; John D.
Attorney, Agent or Firm: Flehr, Hohbach, Test, Albritton
& Herbert
Parent Case Text
This application is a continuation of Ser. No. 063,699, filed June
12, 1987, which is a continuation of Ser. No. 913,639, filed Sept.
30, 1986, which is a continuation of Ser. No. 778,278, filed Sept.
18, 1985, which is a continuation of Ser. No. 326,721, filed Dec.
1, 1981, all now abandoned.
Claims
What is claimed is:
1. A catheter assembly, comprising:
an outer catheter for insertion into a body channel, said outer
catheter having distal and proximal ends;
an inner catheter positionable within said outer catheter and
having a distal end that is extendable toward the distal end of
said outer catheter;
an inflatable means affixed to the outer surface of at least one of
said catheters for forming a seal at the interior walls of the body
channel;
optical fibers extending through a portion of said inner catheter
for illuminating and viewing the area in front of the distal end of
said inner catheter; and
means for positioning said optical fibers relative to the axis of
said outer catheter.
2. The catheter assembly of claim 1 wherein said positioning means
includes a cable and pulley arrangement.
3. The catheter assembly of claim 1 wherein said optical fibers for
illuminating and viewing include:
a plurality of optical fibers extending through a portion of said
inner catheter and terminating within said inner catheter near the
distal end thereof for use in illuminating the area in front of the
distal end of said inner catheter; and
a fiber optic bundle extending through a portion of said inner
catheter and terminating within said inner catheter near the distal
end thereof for use in viewing the area in front of the distal end
of said inner catheter.
4. The catheter assembly of claim 1 further including a flushing
channel extending through a portion of said inner catheter and
terminating within said inner catheter near the distal end
thereof.
5. The catheter assembly of claim 1 further including an optical
fiber extending through a portion of said inner catheter for
transmitting laser energy therethrough for removing an obstruction
outwardly of the distal end of said inner catheter.
6. The catheter assembly of claim 5 further including means for
positioning said laser optical fiber relative to the central axis
of said outer catheter.
7. The catheter assembly of claim 6 wherein said positioning means
includes a cable arrangement.
8. The catheter assembly of claim 5 further including:
flushing and suction channels extending through a portion of said
inner catheter and terminating within said inner catheter near the
distal end thereof.
9. The catheter assembly of claim 5 wherein said viewing and
illuminating optical fibers include:
a plurality of optical fibers extending through a portion of said
inner catheter and terminating within said inner catheter near the
distal end thereof for use in illuminating the area in front of the
distal end of said inner catheter; and
a fiber optic bundle extending through a portion of said inner
catheter and terminating within said inner catheter near the distal
end thereof for use in viewing the area in front of the distal end
of said inner catheter.
10. The catheter assembly of claim 5 wherein said viewing and
illuminating optical fibers comprise:
a fiber optical bundle having a viewing bundle portion for viewing
the area in front of the distal end of said inner catheter, and a
light source bundle portion for illuminating said area.
11. The catheter assembly of claim 10 wherein there are two of said
fiber optical bundles disposed on opposite sides of the central
axis of said inner catheter.
12. A catheter assembly for use in removing an obstruction in a
blood vessel, comprising:
a first catheter for insertion into the blood vessel, sand first
catheter having distal and proximal ends;
a second catheter having distal and proximal ends and of smaller
diameter than said first catheter, said second catheter
positionable within said first catheter such that the distal end of
said second catheter is extendable toward the distal end of said
first catheter;
inflatable means affixed at the exterior surface of at least one of
said catheters near the distal end thereof for sealing against
interior walls of the blood vessel when inflated to prevent the
flow of blood into the area of the obstruction;
optical fibers extending through said second catheter and
terminating near the distal end thereof for use in illuminating and
viewing the obstruction;
at least one optical fiber extending through said second catheter
and terminating near the distal end of said second catheter for
transmitting laser energy therethrough to remove the obstruction;
and
means for positioning said viewing and illuminating optical fibers,
and said laser fiber relative to the central axis of the first
catheter.
13. The catheter assembly of claim 12 wherein said laser fiber is
positioned along the central axis of said second catheter.
14. The catheter assembly of claim 12 wherein that end of said
laser fiber terminating near the distal end of said second catheter
includes a lens for focusing a laser beam on the obstruction.
15. The catheter assembly of claim 12 wherein said positioning
means includes a cable arrangement.
16. The catheter assembly of claim 12 further including:
a flushing tube extending through a portion of said second catheter
and terminating within said second catheter near the distal end
thereof for injecting a flushing fluid, a gas, or a dye into the
area in front of the distal end of said second catheter; and
a suction tube extending through a portion of said second catheter
and terminating within said second catheter near the distal end
thereof for removing said injected fluid, dye and gas, or materials
and gases produced by removal of the obstruction.
17. A method for removing an obstruction in a blood vessel,
comprising:
inserting a first catheter into the blood vessel to a point near
the obstruction to act as a guide for a second catheter, said first
and second catheters having distal and proximal ends;
inserting said second catheter into said first catheter so that the
distal end of said second catheter extends toward the distal end of
said first catheter in proximate relation to the obstruction;
illuminating and viewing the obstruction by means of optical fibers
extending through a portion of said second catheter and terminating
near the distal end thereof;
inflating an expandable member affixed at the outer surface of at
least one of said catheters near the distal end thereof to seal
against the interior walls of the blood vessel so as to block the
flow of blood into the area of the obstruction;
positioning a laser optical fiber which extends through at least a
portion of the second catheter relative to the axis of the second
catheter; and
focusing and transmitting a laser beam through the laser optical
fiber to remove the obstruction.
18. The method of claim 17 further including injecting a fluid into
the area of the obstruction through a flushing tube extending
through said second catheter.
19. The method of claim 18 further including removing through a
suction tube extending through said second catheter said fluids,
and materials and gases produced by removal of the obstruction.
20. The catheter assembly of claim 12 wherein said viewing and
illuminating optical fibers comprise first and second fiber optic
bundles each having a viewing bundle portion for viewing the area
in front of the distal end of said second catheter and a light
source bundle portion for illuminating said area.
21. A catheter assembly, comprising:
an outer catheter for insertion into a body channel, said outer
catheter having distal and proximal ends;
an inner catheter positionable within said outer catheter and
having a distal end extendable toward the distal end of said outer
catheter;
an inflatable means associated with at least one of said catheters
for effecting a seal at the interior walls of the body channel;
optical fibers extending through at least a portion of said inner
catheter for illuminating and viewing the area in front of the
distal end of said inner catheter; and
means for positioning said optical fibers relative to the axis of
said outer catheter.
22. A catheter assembly, comprising:
a first catheter for insertion into a body channel, said first
catheter having distal and proximal ends;
a second catheter of smaller diameter than said first catheter and
positionable within said first catheter such that a distal end of
said second catheter is extendable toward the distal end of said
first catheter;
inflatable means associated with at least one of said catheters
near the distal end thereof for effecting a seal at the interior
walls of the body channel to prevent the flow of a body fluid
therepast; and
first and second fiber optical bundles for viewing the area in
front of the distal end of said second catheter and a light source
bundle for illuminating said area.
23. A catheter assembly for removing an obstruction,
comprising:
an outer catheter insertable into a body channel, said outer
catheter having distal and proximal ends;
an inner catheter having distal and proximal ends and of smaller
diameter than said outer catheter and positionable within said
outer catheter such that the distal end of said inner catheter is
extendable toward the distal end of said outer catheter;
inflatable means associated with at least one of said catheters for
effecting a seal at the interior walls of the body channel to
prevent the flow of a body fluid therepast and into the of the
obstruction;
means carried by said inner catheter for illuminating and viewing
the obstruction; and
means for transmitting laser energy through said inner catheter for
removing the obstruction.
24. The catheter assembly of claim 23 wherein said illuminating and
viewing means comprises optical fibers extending through said
second catheter and terminating near the distal end thereof;
and
said laser transmitting means comprises at least one optical fiber
extending through said second catheter and terminating near the
distal end thereof.
25. The catheter assembly of claim 23 further including means for
positioning said viewing and illuminating means and said laser
transmitting means relative to the central axis of said outer
catheter.
26. A catheter assembly comprising:
a catheter for insertion into a body channel, the catheter having
distal and proximal ends;
an inflatable means associated with the catheter for forming a seal
at the interior walls of a body channel;
optical fibers extending through at least a portion of the catheter
for illuminating and viewing the area in front of the distal end of
the catheter; and
mans for positioning aid optical fibers relative to the axis of the
catheter.
27. The catheter assembly of claim 26 wherein said positioning
means includes a cable means.
28. The catheter assembly of claim 26 further including a channel
extending through at least a portion of said catheter.
29. The catheter assembly of claim 26 further including an optical
fiber extending through at least a portion of the catheter for
transmitting laser energy therethrough for removing an obstruction
outwardly of the distal end of said catheter.
30. The catheter assembly of claim 29 further including means for
positioning said laser optical fiber relative to the central axis
of the catheter.
31. A method for removing an obstruction in a blood vessel,
comprising:
inserting a first catheter into the blood vessel to a point near
the obstruction to act as a guide for a second catheter, said first
and second catheters having distal and proximal ends;
inserting said second catheter into said first catheter so that the
distal end of said second catheter extends toward the distal end of
said first catheter in proximate relation to the obstruction;
illuminating and viewing the obstruction by means of optical fibers
extending through a portion of said second catheter and terminating
near the distal end thereof;
inflating an expandable member associated with at least one of said
catheters to effect a seal at the interior walls of the blood
vessel so as to block the flow of blood into the area of the
obstruction;
positioning a laser optical fiber which extends through at least a
portion of the second catheter relative to the axis of the first
catheter; and
focusing and transmitting a laser beam through the laser optical
fiber to remove the obstruction.
Description
The present invention relates generally to catheter assemblies, and
more particularly to a catheter assembly for diagnostic use or for
use in removing an obstruction in a blood vessel, body channel or
body cavity.
The American Heart Association has estimated that approximately
four million people in the United States suffer from
arteriosclerotic coronary artery disease. Many of these people are
likely to suffer or die from a myocardial infraction, commonly
known as a heart attack. Heart attacks are in fact the leading
cause of death in the United States. Thrombosis in the coronary
artery beyond the arteriosclerotic constriction is the usual cause
of heart attacks. A procedure which can open arteriosclerotic
constrictions, thereby permitting the normal flow of blood to the
heart, may reduce the many deaths and disabilities caused by heart
disease.
Constrictions in the coronary artery are caused by a build-up of
plaque, which may be "hard" or "soft". Plaque consists of calcium,
fibrous and fatty substances. If the plaque is of recent origin or
"soft", that is, it has a low concentration of calcium, a
"Gruntzig" balloon catheter may be used to clear the artery. The
"Gruntzig" catheter is inserted into the constricted area of the
artery, and the balloon is inflated to expand and compress the
plaque, thereby opening the artery and permitting an increased flow
of blood through the artery. The "Gruntzig" balloon catheter is
described in the following article: "Nonoperative Dilatation of
Coronary-Artery Stenosis", A.R. Gruntzig, M.D., A. Senning, M.D.,
and W.E. Siegenthaler, M.D., The New England Journal of Medicine,
Vol. 301, No. 2, July 12, 1979. See also U.S. Pat. No. 4,195,637,
Gruntzig, et al., issued Apr. 1, 1980.
The "Gruntzig" technique, however, does not work where the
constriction in the artery is very tight, where the plaque is "old"
and hard, or where the plaque forming the constriction has a high
concentration of calcium and thus is very hard. It is estimated
that the "Gruntzig" technique can be successfully used on only
about 5% of the patients suffering from arteriosclerotic coronary
disease.
Accordingly, the present invention is directed to a catheter
assembly which can remove (a) plaque, especially when hard, and (b)
operate in a very constricted area of an artery. The catheter
assembly of the present invention may also be used to remove
obstructions from other blood vessels and body channels or
cavities, as well as to view a region of a blood vessel or a
non-vascular body channel.
The present invention also provides a catheter assembly which is
able to temporarily interrupt the flow of blood to an occluded or
constricted region while such region is treated or observed.
The catheter assembly of the present invention includes a first or
outer catheter having distal and proximal ends, and a second or
inner catheter which is positionable within the first catheter. The
second catheter has a smaller diameter than the first catheter, and
preferably, the second catheter is more flexible. The second
catheter is positioned within the first catheter so that the second
catheter can be shifted or moved with respect to the first
catheter. Also, the distal end of the second catheter is extendable
past the distal end of the first catheter. Inflatable means such as
an expandable balloon is affixed to the outer surface of at least
one of the catheters near the distal end thereof. When inflated,
the balloon sealingly engages the interior walls of the blood
vessel or the like in which the catheter assembly is inserted. This
is done to stop the flow of blood into the area of the blood vessel
in front of the distal end of the second catheter and thus to
facilitate visualization of the obstructed or constricted
region.
A plurality of optical fibers extend through a portion of the
second catheter and terminate at a point within the second catheter
near its distal end. Usually one bundle of optical fibers is used
for illuminating and another bundle of optical fibers is used for
viewing the area in front of the distal end of the second
catheter.
Where the catheter assembly is to be used to remove an obstruction
in a blood vessel, such as plaque material in the coronary artery
or a clot, a special fiber capable of transmitting energy in the
form of a laser beam extends through a portion of the second
catheter and terminates near the distal end thereof. An appropriate
lens may be attached to that end of the "laser fiber" located at
the distal end of the second catheter. The lens focuses and
intensifies the laser beam. In order to remove the obstruction, the
laser has to deliver to the target area power sufficient to
destroy, vaporize or soften the obstruction.
Additionally, one or more channels may be provided within the
catheter assembly for removal of combustion material generated
during laser irradiation and for flushing of body fluids trapped
between an occlusion and the adjacent catheter assembly. Suitable
flushing fluids for this purpose are saline solutions, Ringer's
solution, and the like. These channels may also be used to infuse a
radio-opaque dye in the region.
Appropriate positioning means may also be provided within the
catheter assembly for positioning the laser fiber, and the viewing
and illuminating optical fibers relative to the central axis of the
catheter assembly.
The catheter assembly embodying the present invention may include
fiber optics for viewing and illuminating a body region, a fiber
optic for transmitting a laser beam to a region within the
patient's body, or both types of fiber optics, as desired.
Alternatively, both types of fiber optics may be omitted and the
catheter assembly of the present invention used to pretreat the
plaque, occlusion or clot with a chemotherapeutic substance. In
this later embodiment, the catheter assembly could be guided to the
occlusion or clot by such means as fluoroscopy. Fluoroscopy could
also be used to guide the catheter assembly to the target area
where the assembly includes only a laser fiber optic.
The catheter assembly of the present invention will be described in
more detail hereinafter in conjunction with the drawings
wherein:
FIG. 1A through 1C are schematic, side views, partly in section,
illustrating the positioning of the inner catheter within the outer
catheter of the catheter assembly of the present invention.
FIG. 2 is a schematic, sectional view of the catheter assembly of
the present invention.
FIG. 3 is a schematic, sectional view along the central axis of the
inner catheter of the catheter assembly of the present
invention.
FIG. 4 is a schematic, sectional view of an alternative embodiment
of the catheter assembly of the present invention.
FIGS. 5 and 6 are schematic views, partly in section, of a
positioning means used with the catheter assembly of the present
invention.
FIG. 7 is a schematic, sectional view along the central axis of the
inner catheter illustrating an alternative embodiment of the
catheter assembly of the present invention.
FIG. 8 is a schematic, side view of the catheter assembly of the
present invention wherein the inflatable means is affixed to the
outer surface of the outer catheter.
The present invention will be described in conjunction with its
most suitable use: the removal of plaque material from the coronary
artery. The catheter assembly of the present invention, however,
can also be used to remove occlusions, such as clots, in other
arteries and veins. The present invention is especially useful in
very constricted areas of blood vessels and for removing very hard
material. Further, the catheter assembly could be used where it is
necessary to temporarily stop the flow of blood to permit visual
inspection and to achieve successful removal of an occlusion. The
catheter assembly could also be used without its associated laser
apparatus where it is simply desired to view an area of a blood
vessel, some non-vascular body channel, or the interior of an organ
or cavity. The present invention could also be used to remove
obstructions from non-vascular body channels; for example, it could
be used to remove bladder, kidney and gall stones.
Referring now to the drawings, in which like components are
designated by like reference numerals throughout the various
figures, attention is first directed to FIGS. 1A through 1C. FIGS.
1A through 1C show catheter assembly 10 of the present invention
positioned for use in removing plaque 92 from coronary artery 90.
Catheter assembly 10 comprises a guide or outer catheter 12 and a
second or inner catheter 14. Guide catheter 12 has been inserted
into an arm, leg or other artery 96 to extend near orifice 94 of
the coronary artery. The guide catheter is guided through such
artery to the orifice by procedures well known in the art, such as
fluoroscopy. Alternatively, catheter 12 may be an existing
pre-formed catheter or articulated endoscope, adapted as described
herein.
Catheter 14 is positioned in coronary artery 90 by inserting it
through guide catheter 12. Catheter 12 guides catheter 14 from the
point of insertion, which is at the proximal end 12b of catheter
12, into coronary artery 90. To facilitate movement of catheter 14
within guide catheter 12, catheter 14 is more flexible than
catheter 12. Catheter 14 also has a smaller outside diameter than
the guide catheter. The outside diameter of catheter 12 is about
2.5 to 3.5 millimeters for use within the coronary artery. For
other blood vessels or body channels, the outside diameter of
catheter 12 may be selected accordingly. The outside diameter of
catheter 14 is approximately 1.5 to 2.5 millimeters. In instances,
where the catheter assembly does not include optical fibers for
viewing and illuminating, the outside diameter of catheter 14 can
be as small as about 1 to 2 millimeters.
In use, catheter 14 is inserted in and pushed through the guide
catheter until its distal end 14a extends beyond distal end 12a of
the guide catheter, see FIGS. 1A through 1C. Inflatable means 16,
discussed in more detail below, is affixed to inner catheter 14 at
the distal end thereof. The inflatable means is collapsed as the
inner catheter moves through the guide catheter, see FIGS. 1A and
1B. After distal end 14a of the inner catheter has been positioned
near plaque buildup 92 by such means as fluoroscopy and the viewing
and illuminating fiber optics, which are discussed below,
inflatable means 16 is inflated as shown in FIG. 1C. Radio-opaque
bands 56 may be located at distal end 14a so that the position of
distal end 14a and inflatable means 16 can be precisely determined
by use of the fluoroscope.
To illuminate stenotic obstruction 92, an optical fiber bundle
comprising a plurality of optical fibers 22 is provided within
catheter 14, see FIGS. 2 and 3. Optical fibers 22 originate at an
exterior intense viewing light source, which is not illustrated,
and extend from the proximal end 14b of catheter 14 to a point
within the catheter near its distal end 14a. Optical fibers 22 are
used to illuminate the area in front of the distal end of catheter
14.
Catheter 14 further includes an optical fiber bundle 20 consisting
of a plurality of optical fibers for viewing the area in front of
distal end 14a. Bundle 20 is connected to an appropriate eyepiece,
which is not illustrated, and extends from the proximal end 14b of
catheter 14 to terminate at a point within the catheter near distal
end 14a. If desired, a protective transparent shield may be
provided over the distal end of bundle 20. Viewing bundle 20 forms
an image that is produced and viewed by conventional means as in a
medical endoscope. Bundle 20, which is offset from central axis 17
of catheter 14, collects light through a tilted lens 32. Lens 32
permits observation of the central portion of the artery, the
surrounding area, and the occlusion.
A laser-beam transmitting fiber 26 for transmission of laser energy
from a laser source 34 is also carried by catheter 14.
Laser-transmitting fiber 26 extends from proximal end 14b of
catheter 14 to a point inwardly of but near the distal end of
catheter 14. Fiber 26 is preferably located along the central axis
of catheter 14, and may also be covered by a transparent shield if
desired.
Laser 34 is coupled to laser-transmitting fiber 26 by a lens 36,
which is either placed between the laser and the laser-transmitting
fiber, as illustrated, or which is incorporated into the optical
fiber. The exterior surface of laser transmitting fiber 26 is
coated with an anti-reflective coating for the laser wavelength of
interest. A shutter 38 between laser 34 and lens 36 permits control
of laser irradiation. Endoscopes used in conjunction with lasers
for the performance of surgery are discussed in U.S. Pat. No.
3,858,577, issued Jan. 7, 1975, Bass, et al., and U.S. Pat. No.
4,146,019, issued Mar.27, 1979, Bass, et al. The disclosures in
these two patents are hereby incorporated by reference.
Laser 34 has to deliver to the target area sufficient power at the
predetermined wavelength to destroy, vaporize or soften plaque
material 92. The laser beam should be conducted through optical
fiber 26 with as little power loss as feasible. Additionally, the
laser should interact with the plaque material rather than with the
surrounding normal tissue of the artery or any infrared liquid that
may be present. Several types of lasers can be used, for example,
argon-ion, carbon dioxide, and Neodynium YAG lasers. Lasers having
a wavelength capable of destroying or softening plaque but without
adverse effect on blood cells or tissue are preferred. For lasers
of certain wavelengths, for instance, carbon dioxide lasers, some
laser-transmitting guide other than an optical fiber might have to
be used.
To achieve the high intensities required for destruction of plaque
material 92, the laser is focused by a short-focal length lens 28.
Lens 28 is either spaced from the end of optical fiber 26, or, as
shown, affixed to the end of optical fiber 26. Lens 28 may comprise
a plurality of lenses.
The laser will destroy blood cells present and may produce blood
clotting in the area of the targeted occlusion. Clotting in the
occluded coronary artery would further compromise blood flow to the
heart. Thus, laser surgery in the coronary artery requires that
blood flow to the targeted occlusion be stopped. Catheter assembly
10 includes an inflatable or expandable balloon 16 for temporarily
stopping the flow of blood into the area in front of the distal end
of catheter 14. Blood flow in the coronary artery, however, cannot
be interrupted for more than 12 to 15 seconds without endangering
the patient's life. By temporarily interrupting the flow of blood,
blood can be excluded from the region, the obstructed or
constricted area can be viewed, and the obstruction can be
successfully removed. The region in front of the distal end of
catheter 14 can also be flushed with a solution, such as Ringer's
or saline, to dilute any blood present in that region. Perhaps, a
gas such as carbon dioxide could also be injected into this region
to expand the artery, and to clear blood from the ends of the
optical fibers.
Inflatable balloon 16 is circumferentially affixed about the
exterior surface of catheter 14, and is located near the distal end
of catheter 14. Prior to opening shutter 38, balloon 16 is inflated
to sealingly engage the interior walls of coronary artery 90,
thereby stopping the flow of blood into the area of targeted
occlusion 92, see FIG. 1C. The laser will vaporize the occlusion
within a time period of less than one second depending upon the
type and power of laser used. Afterwards, balloon 16 may be
deflated to permit blood flow through the coronary artery, or if
time permits, catheter 14 may be extended further to remove or
soften an additional section of plaque before the flow of blood is
restored.
As balloon 16 only has to stop the flow of blood and not expand the
artery, the balloon can be inflated by lower pressures and be
constructed of less rigid materials than a "Gruntzig"-type balloon.
Alternatively, balloon 16 may be constructed to stop blood flow as
well as to expand soft plaque or any other deformable construction
in an artery.
In an alternate embodiment, as illustrated in FIG. 8, catheter
assembly 10 may have inflatable means 16 circumferentially affixed
about the exterior surface of catheter 12 near the distal end 12a
thereof. This embodiment is particularly useful in the removal of
plaque or clot 102 found in a peripheral vessel 100, such as the
iliar and femoral arteries.
A pair of channels 18, see FIG. 2, extend through catheter 14 and
are connected to the interior of balloon 16 by means of a flexible
tubing 18a. A gas, such as carbon dioxide, or a liquid, such as
saline, is passed through channels 18 from a source, which is not
illustrated, to expand balloon 16. To deflate the balloon, the gas
or fluid may be withdrawn from the balloon by means of these
channels. Channels 18 may also be built into the wall of catheter
14.
A cable pulley arrangement is provided to position catheter 14
which carries the laser, illumination, and viewing fiber optics. As
shown in FIG. 2, the cables are attached at appropriate points 80
to a sheath 82 which is disposed circumferentially about optical
fibers 22, viewing bundle 20, and laser fiber 26. Sheath 82 may
extend the length of the optical fibers back to proximal end 14b of
catheter 14. Sheath 82 defines a grouping 30 of fiber optics within
the central section of catheter 14. The grouping includes viewing
bundle 20, laser optical fiber 26, and illumination optical fibers
22. As in gastroendoscopy, the cable pulley arrangement can be
operated to tilt grouping 30 or to cause it to move transversely
relative to the central axis of the catheter assembly. This permits
viewing and laser irradiation of sites in the artery which are not
centrally located with respect to catheter 14. Alternatively, as
shown in FIG. 8, cables 81 of the cable pulley arrangement may be
attached at appropriate points 80 to the outside surface of
catheter 14 at the distal end thereof. The illumination fiber
optics of catheter 10 have been described as comprising a plurality
of individual optical fibers 22 disposed within catheter 14. It is
to be understood, however, that a fiber optical bundle, like bundle
20, could be fashioned to include both illumination and viewing
optical fibers. Such an approach is described below.
An alternative embodiment of the catheter assembly of the present
invention is illustrated in FIGS. 4 through 7. In that embodiment,
catheter assembly 120 includes two fiber optical bundles 42 and 44
to provide binocular vision, and thus depth perception of the
target area. Each bundle 42 and 44 in turn includes an illumination
bundle portion connected to an intense light source for
illuminating the area in front of distal end 14a, and a viewing
bundle portion connected to an eyepiece for viewing the area in
front of distal end 14a.
Bundles 42 and 44 are located on either side of the central axis of
catheter 14, and they collect light through their own respective
tilted lenses 33 and 35. The lenses are suitably tilted to allow
observation of the central portion of the artery as well as the
surrounding area. This stereoscopic binocular approach permits
perception of depth within the artery. As in the embodiment
described above, bundles 42 and 44 permit observation of a wide
area of the coronary artery, as well as the .obstruction and laser
focal spot.
The embodiment illustrated in FIG. 7 also includes an intense
coherent light source 60 which is located between laser 34 and
laser fiber optic 26. Light source 60 is slightly offset from the
laser propagation axis. Light source 60 permits viewing of the
precise region of the laser focus as well as the exact size of the
focused laser beam. An optical filter 61 and a beam splitter 62 are
located between light source 60 and laser fiber optic 26 to help
distinguish the laser focal region from the region of general
illumination. Light source 60 serves as an aiming beam or target
light when lasers having an invisible wavelength are used.
Catheter assembly 120 further includes a flushing tube 70 and a
suction tube 72. Both of these tubes extend within catheter 14 from
its proximal end 14b to a point inwardly of distal end 14a, see
FIGS. 4 through 6.
Flushing tube 70 is provided for injecting a flushing fluid, such
as saline or Ringer's solution, into the area between the distal
end of catheter 14 and the occlusion. The flushing fluid can be
injected to dilute and/or remove any trapped blood, after blood
flow to the occlusion is stopped by balloon 16. A radio-opaque dye
may also be injected into this area through flushing tube 70 so
that the dye may be viewed on a fluoroscope to determine the site
of the obstruction. A gas such as carbon dioxide could also be
injected through flushing tube 70. Suction tube 72, which is
connected to an appropriate filtering system outside of catheter
14, is designed to remove the aforesaid diluted blood and flushing
fluid, dye, or any products that may form after the plaque material
has been vapored or otherwise removed by the laser.
Grouping 30 of catheter assembly 120 includes laser-transmitting
fiber optic 26, and fiber optic bundles 42 and 44. Grouping 30 also
includes flushing and suction tubes 70 and 72. To position grouping
30, a series of positioning balloons 50 are disposed
circumferentially about the grouping. Inflatable balloons 50 are
each operably connected to independent pressure sources, which are
not illustrated, via tubes, also not illustrated, extending from
the proximal end of catheter 14. As with the cable pulley
arrangement, inflatable balloons 50 permit grouping 30 to move
transversely and tilt relative to the central axis of the catheter
assembly. The positioning-balloon system permits viewing and laser
irradiation of sites that are not centrally located relative to the
central axis of catheter 14.
As shown in FIGS. 5 and 6, where reference numeral 39 represents
the central axis of grouping 30, by inflating some balloons and
deflating others, grouping 30 can be appropriately positioned
relative to the target area. FIG. 5 shows an arrangement where
grouping 30 has been moved transversely with respect to the central
axis of the catheter assembly. FIG. 6 shows an arrangement in which
grouping 30 has been moved transversely and tilted.
In other embodiments, the catheter assembly of the present
invention could employ more than one laser.
The laser-transmitting fiber could also be offset from the central
axis of the inner catheter and could use a tilted or nonsymmetrical
lens. Different configurations of the viewing and illuminating
optical fibers are also possible.
Although certain specific embodiments of the invention have been
described herein in detail, the invention is not to be limited to
only such embodiments, but rather only by the appendant claims.
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