U.S. patent application number 09/916642 was filed with the patent office on 2002-02-21 for apparatus and methods for material capture and removal.
Invention is credited to Boyd, Stephen, Corvi, Tim, Doud, Darren G., Follmer, Brett, Snow, David W., Stine, John G..
Application Number | 20020022788 09/916642 |
Document ID | / |
Family ID | 23490904 |
Filed Date | 2002-02-21 |
United States Patent
Application |
20020022788 |
Kind Code |
A1 |
Corvi, Tim ; et al. |
February 21, 2002 |
Apparatus and methods for material capture and removal
Abstract
Catheters, kits, and methods are provided for removing material
from a body lumen. The catheters and methods may be used in a
variety of body lumens, including but not limited to coronary and
other arteries. In general, the catheter has a cutting element that
cuts material while the material is engaged by a material capture
device on the catheter body. Preferably, the material capture
device tensions the material during cutting, which reduces the
amount of cutting force required. The material capture device
typically follows a path that draws material into the catheter
body. Preferably, but not necessarily, the material capture device
may be arranged on the catheter body to advance along a path
outwardly from the catheter body into the material and then
inwardly towards the catheter body to tension the material. The
cutting element on the catheter body moves between a first position
and a second position to cut the material while in tension.
Inventors: |
Corvi, Tim; (Belmont,
CA) ; Boyd, Stephen; (Moss Beach, CA) ;
Follmer, Brett; (Santa Clara, CA) ; Stine, John
G.; (San Jose, CA) ; Snow, David W.; (San
Carlos, CA) ; Doud, Darren G.; (San Jose,
CA) |
Correspondence
Address: |
TOWNSEND AND TOWNSEND AND CREW, LLP
TWO EMBARCADERO CENTER
EIGHTH FLOOR
SAN FRANCISCO
CA
94111-3834
US
|
Family ID: |
23490904 |
Appl. No.: |
09/916642 |
Filed: |
July 27, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
09916642 |
Jul 27, 2001 |
|
|
|
09377884 |
Aug 19, 1999 |
|
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Current U.S.
Class: |
600/564 |
Current CPC
Class: |
A61B 17/320783 20130101;
A61B 2017/320791 20130101; A61B 2017/320064 20130101; A61B 10/04
20130101; A61B 10/0275 20130101 |
Class at
Publication: |
600/564 |
International
Class: |
A61B 010/00 |
Claims
What is claimed is:
1. A catheter for removing material from a body lumen, said
catheter comprising: a catheter body having a proximal end and a
distal end; a material capture device arranged on said catheter
body to engage said material; and a cutting element mounted near
the distal end of the catheter body to move between a first
position and a second position to cut said material while said
material is engaged by said material capture device, wherein motion
of the cutting element urges the material capture device to draw
cut material into the catheter body.
2. A catheter as in claim 1 wherein said catheter body comprises a
proximal, flexible portion and a distal, rigid portion containing
said cutting element.
3. A catheter as in claim 2 wherein said catheter body comprises a
inner cutter mounted coaxially within said distal, rigid portion,
said material capture device mounted on said inner cutter.
4. A catheter as in claim 2 wherein said catheter body comprises an
atraumatic distal tip mounted on said distal, rigid portion.
5. A catheter as in claim 1 wherein: said material capture device
is arranged on said catheter body to advance along a path outwardly
from the catheter body into said material and then inwardly towards
the catheter body to tension said material; and said cutting
element on said catheter body moving between said first position
and said second position to cut said material while in tension.
6. A catheter as in claim 5 wherein said path comprises a radially
curved path extending in an outward direction away from the
catheter body towards said material to be cut off.
7. A catheter as in claim 6 where in said material capture device
moving along said path does not exceed the outer diameter of the
catheter body.
8. A catheter as in claim 5 wherein said material capture device
travels in a slot on the catheter body to advance along said
path.
9. A catheter as in claim 5 wherein said material capture device
travels in a groove on the catheter body to advance along said
path.
10. A catheter as in claim 5 wherein said material capture device
comprises a bias element to urge said material capture device along
said path.
11. A catheter as in claim 5 wherein said material capture device
is configured to rotate about a pivot pin to deploy said material
capture device along said path.
12. A catheter as in claim 1 wherein said material capture device
comprises: a penetrating member pivotably mounted about a pin on
said cutting blade, said penetrating member movable between a
first, tissue-engaging position and a second tissue-retracting
position; and a cam surface disposed on said catheter body to
contact and rotate said penetrating member about said pivot point
when said cutting blade is advanced over the cam surface.
13. A catheter as in claim 12 wherein said cam surface is
configured to slidably contact a lower surface on said penetrating
member to guide said penetrating member over an accurate path as
the cutting blade is advanced.
14. A catheter as in claim 13 wherein said cam surface includes a
groove for mating with said penetrating member.
15. A catheter as in claim 13 wherein said cam surface includes a
first groove having a funneled opening and a second groove having a
second funneled opening.
16. A catheter as in claim 13 wherein said penetrating member
comprises a recess on said lower surface to facilitate positioning
of said member over said cam surface.
17. A catheter as in claim 1 wherein said material capture device
comprises: a penetrating member rotatably mounted on said cutting
element; and an abutment disposed on said catheter body to engage
one end of the penetrable member and cause rotation of the
penetrating member from a first, open position to a second, closed
position.
18. A catheter as in claim 17 further comprising a tether coupled
to said penetrating member to control positioning of the
penetrating member.
19. A catheter as in claim 1 wherein said material capture device
comprises a penetrating member rotatably mounted on said catheter
body and fixedly secured relative to said slidable cutting element;
a pushing element mounted on said cutting element to engage said
penetrating member to move said member between a first position to
a second tissue-engaging position.
20. A catheter as in claim 1 wherein said material capture device
is configured to be deployed from an aperture in the side wall of
the catheter body.
21. A catheter as in claim 20 wherein said cutting element includes
an material imaging device mounted to be in an imaging position
when said aperture is closed by said cutting element.
22. A catheter as in claim 1 wherein said cutting element includes
a first cutting blade having at least one penetrating point.
23. A catheter as in claim 1 wherein said cutting element has a
first cutting blade opposed to a second cutting blade for removing
said material.
24. A catheter as in claim 1 wherein said cutting element comprises
a tubular inner cutter slidably mounted within an outer cutter of
the catheter body, said inner cutter coupled to a drive wire
actuated by a user.
25. A catheter as in claim 1 wherein said material capture device
extends an extension distance outward from the catheter body to
engage material, said extension distance equal to the diameter of
the catheter body.
26. A catheter as in claim 1 wherein said material capture device
includes a barbed distal tip to retain material on the capture
device.
27. A catheter as in claim 1 wherein said cutting element further
comprises a material imaging device.
28. A catheter as in claim 27 wherein said material imaging device
comprises an ultrasound transducer array.
29. A catheter as in claim 1 wherein said material capture device
comprises means for penetrating said material.
30. A catheter as in claim 29 wherein said means for penetrating
material comprises a curved needle biased outwardly from the
catheter body.
31. A catheter as in claim 29 wherein said means for penetrating
material comprises a penetrating member rotatably mounted about a
pivot pin on said cutting element.
32. A catheter as in claim 29 wherein said means for penetrating
material is configured to engage a raised portion on said catheter
body to move said means to engage material and then retract
material into the catheter body.
33. A catheter as in claim 32 wherein said raised portion comprises
a cam surface having a plurality of tracks, wherein each track has
a funneled entrance to guide said penetrating member therein.
34. A catheter for removing material from the wall of a body lumen,
said catheter comprising: a catheter body having a proximal end and
a distal end; a side aperture on the catheter body; a cutting blade
adapted to advance past the aperture to sever material which
intrudes through the aperture; and a penetration member mounted to
extend through the aperture to penetrate material in advance of the
cutting blade and to draw material into the catheter body as the
cutting blade is advanced past the aperture.
35. A catheter as in claim 34 further comprising a cam surface
mounted on said catheter body, said cam surface having a surface
configured to guide said penetration member into said material when
said blade is advanced.
36. A catheter for removing material from a body lumen, said
catheter comprising: a catheter body having a proximal end and a
distal end; a material capture device arranged on said catheter
body to advance along a path radially outwardly from the catheter
body into said material and then inwardly towards the catheter body
to tension said material; and a cutting element on said catheter
body moving between a first position and a second position to cut
said material while said material is in tension.
37. A catheter for removing material from a body lumen, said
catheter comprising: a catheter body having a proximal end, a
distal end, and an aperture; a slidable, telescoping portion on
said catheter body configured to extend outwardly from said
aperture on the catheter body, said telescoping portion having a
first open position leaving a gap between one edge of said portion
and said catheter body to define a cutter window in which material
may intrude to be engaged and having a second closed position
wherein said cutting blade is positioned to cut off said
material.
38. A catheter as in claim 37 wherein said gap defines a
side-opening cutter window.
39. A catheter as in claim 37 wherein said aperture comprises a
forward facing, distal aperture on the catheter body.
40. A catheter as in claim 37 further comprising a material capture
device mounted on said telescoping portion, said portion moving
between a first position and a second position to cut said material
while said material is engaged by said material capture device,
wherein motion of the telescoping portion urges the material
capture device to draw cut material into the catheter body.
41. A catheter as in claim 40 wherein said material capture device
is rotatably mounted to said telescoping portion and configured to
engage a raised portion on said catheter body to rotate said
material capture device to engage material and then draw material
into the catheter body.
42. A method for excising occlusive material from within a body
lumen, said method comprising: capturing said occlusive material
with a material capture device on a catheter body; drawing said
device radially inwardly towards the catheter body to tension the
material; and advancing a blade through the tensioned material to
sever said material from the body lumen.
43. A method as in claim 42 wherein said engaging of said occlusive
material comprises extending said material capture device from said
catheter body in a radially outward direction.
44. A method as in claim 43 wherein said material capture device
does not extend beyond the outer diameter of the catheter body when
engaging said material.
45. A method as in claim 42 wherein said engaging of said occlusive
material comprises penetrating said material with said material
capture device.
46. A method as in claim 42 wherein said engaging of occlusive
material comprises radially extending said material capture device
outward from an aperture on the catheter body.
47. A method as in claim 46 wherein said engaging of said occlusive
material comprises guiding said material capture device against a
raised portion on the catheter body to direct said capture device
into said material.
48. A method as in claim 46 wherein said engaging of said occlusive
material comprises advancing said cutting blade to engage a pushing
element against said material capture device mounted on the
catheter body.
49. A method as in claim 46 wherein said engaging of said occlusive
material comprises penetrating said material in advance of the
blade and said drawing of said device into the catheter body occurs
as the cutting blade is advanced past the aperture.
50. A method as in claim 46 further comprising imaging said
material prior to cutting said material, wherein said imaging
occurs when said aperture is closed by said cutting blade.
51. A method as in claim 42 wherein said drawing of the device
comprises moving said material capture device radially towards said
catheter body while said material capture device remains in contact
with said material.
52. A method as in claim 51 wherein said drawing of said material
capture device occurs when said cutting element is advanced, said
cutting element pushing against said material capture device and
biasing it into the catheter body.
53. A method as in claim 51 wherein drawing of said material
capture device comprises positioning said material capture device
against a raised portion on the catheter body to guide said device
with the material into the catheter body.
54. A method as in claim 42 wherein said engaging and tensioning of
material are performed through a single motion by the user.
55. A method for removing material from a body lumen, said method
comprising: positioning a catheter within the lumen; extending a
distal portion of the catheter forwardly to open an aperture,
wherein material is invaginated into the aperture; and closing the
distal portion of the catheter to close the aperture and sever the
invaginated material.
56. A method as in claim 55, wherein the body lumen is a blood
vessel and the material is atheromatous material.
57. A method as in claim 55, further comprising penetrating the
tissue with a material capture device and drawing the captured
material into the aperture with the device as the distal portion of
the catheter body is closed.
58. A kit comprising: a catheter having a material capture device
and a cutting element; instructions for use in removing material
from a body lumen comprising engaging said material with a material
capture device and tensioning said material towards the catheter
while cutting said occlusive material with a cutting element; and a
package adapted to contain the device and the instructions for use.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates generally to apparatus and
methods for removing occluding materials from body lumens. More
particularly, the present invention relates to the construction and
use of atherectomy catheters for excising atheroma and other
materials from blood vessels.
[0002] Cardiovascular disease frequently arises from the
accumulation of atheromatous material on the inner walls of
vascular lumens, particularly arterial lumens of the coronary and
other vasculature, resulting in a condition known as
atherosclerosis. Atherosclerosis occurs naturally as a result of
aging, but may also be aggravated by factors such as diet,
hypertension, heredity, vascular injury, and the like. Atheromatous
and other vascular deposits restrict blood flow and can cause
ischemia which, in acute cases, can result in myocardial
infarction. Atheromatous deposits can have widely varying
properties, with some deposits being relatively soft and others
being fibrous and/or calcified. In the latter case, the deposits
are frequently referred to as plaque.
[0003] Atherosclerosis can be treated in a variety of ways,
including drugs, bypass surgery, and a variety of catheter-based
approaches which rely on intravascular widening or removal of the
atheromatous or other material occluding a blood vessel. Of
particular interest to the present invention, a variety of methods
for cutting or dislodging material and removing such material from
the blood vessel have been proposed, generally being referred to as
atherectomy procedures. Atherectomy catheters intended to excise
material from the blood vessel lumen generally employ a rotatable
and/or axially translatable cutting blade which can be advanced
into or past the occlusive material in order to cut and separate
such material from the blood vessel lumen. In particular,
side-cutting atherectomy catheters generally employ a housing
having an aperture on one side, a blade which is rotated or
translated by the aperture, and a balloon or other deflecting
structure to urge the aperture against the material to be
removed.
[0004] Although atherectomy catheters have proven to be very
successful in treating many types of atherosclerosis, some catheter
designs suffer from certain limitations. For example, many
side-cutting atherectomy catheters have difficulty in capturing
occluding material in the cutting aperture. To facilitate material
capture, the cutting aperture is frequently elongated. Although
improving material capture, such lengthening makes it more
difficult to introduce the distal end of the catheter through
torturous regions of the vasculature. Additionally, it is often
difficult for conventional atherectomy cutters to apply the
requisite pressure to cut off the targeted material. When higher
pressures are applied, damage to the artery (barotrauma) can occur.
High pressures can also compress plaque, subsequently reducing the
cutter's ability to capture the occlusive material. This decreases
the effectiveness of these cutters and limits the cutter and
catheter designs.
[0005] For these reasons, it is desired to provide atherectomy
catheters which can access small, tortuous regions of the
vasculature and which can remove atheromatous and other occluding
materials from within blood vessels in a controlled fashion with
minimum risk of injuring the blood vessel wall. In particular, it
is desired to provide atherectomy catheters which can facilitate
capturing of occlusive material. It would also be particularly
desirable to decrease the amount of force required to cut off
occlusive material from the body. At least some of these objectives
will be met by the catheter and method of the present invention
described hereinafter and in the claims.
SUMMARY OF THE INVENTION
[0006] The present invention provides catheters, kits, and methods
for removing material from a body lumen. The catheters and methods
of the present invention are for use in a variety of body lumens,
including but not limited to intravascular lumens such as the
coronary artery and other blood vessels. In general, the catheter
of the present invention has a cutting element that cuts material
engaged by a material capture device on the catheter body.
Preferably, the material capture device tensions the material
during cutting, which reduces the amount of cutting force required.
The material capture device typically follows a path that draws
material into the catheter body. Preferably, but not necessarily,
the material capture device is arranged on the catheter body to
advance along a path outwardly from the catheter body into the
material and then inwardly towards the catheter body to tension the
material. In some embodiments, the material capture device may
extend in an outwardly direction but not beyond the outer diameter
of the catheter body. The cutting element on the catheter body
moves between a first position and a second position to cut the
material while in tension, where motion of the cutting element
urges the material capture device to draw cut material into the
catheter body.
[0007] Desirably, the blade or blades of the catheter will be
actuable with the application of reasonable mechanical forces which
are capable of being transmitted along even rather lengthy
catheters. Further desirably, the catheters will be suitable for
directional removal of occluding material and may include
mechanisms for engaging cutting blades against selected portions of
a vascular wall. Optionally, the engaging mechanisms should permit
blood perfusion during performance of an atherectomy procedure.
[0008] In one embodiment, the catheter of the present invention
uses a material capture device in the form of a material capture
needle. The needle will be deployed in a radially outward direction
from the catheter body. Preferably, but not necessarily, the needle
will capture material while the catheter remains stationary. Some
embodiments may use a plurality of material capture needles. The
material capture needle may follow a path outwardly from the
catheter body in various manners. In one embodiment, the needle has
a portion that advances through an elongate slot on the catheter
body to move the needle along a path outwardly from the catheter
body. Another embodiment uses a curved needle rotatably mounted
about a pivot pin. As the needle is rotated, it will protrude
outwardly from the catheter body. A preferred embodiment uses a
needle having a bias element which urges the needle outwardly when
the catheter is in position. Typically, a material cutting element
will engage the material that has been captured and sheer off the
material into the catheter.
[0009] In a further embodiment, a material capture device of the
present invention uses a penetrating member mounted to extend
through an aperture on the catheter body to penetrate material in
advance of the cutting blade and to draw material into the catheter
body as the cutting blade is advanced past the aperture. The
penetrating member is rotatably mounted to the slidable cutting
blade on the catheter body. A cam surface on the catheter body
engages a surface of the penetrating member to guide the member
along a path to engage the material and draw the material into the
catheter body. In a still further embodiment, an abutment or raised
portion on the catheter body is mounted to engage one end of the
penetrating member. This contact caused the penetrating member to
rotate about its pivot point on the cutting blade and thus engage
material and draw material into the catheter body.
[0010] In another aspect of the present invention, a method is
provided for excising occlusive material from within a body lumen.
The method involves engaging the occlusive material with a material
capture device on a catheter body. The material is drawn in a
radially inward direction by the device to tension the material to
be cut. A blade is advanced through the tensioned material to sever
the material from the body lumen. As mentioned previously,
tensioning the material reduces the amount of cutting force
required. The tensioning of the occlusive material may also
comprise moving the material capture device towards a catheter body
while the material capture device is in contact with the occlusive
material. Typically, the engaging and tensioning steps may also be
performed with a single motion by the user to facilitate
cutting.
[0011] In a still further aspect, kits according to the present
invention will comprise a catheter having a material capture
device. The kits will further include instructions for use setting
forth a method as described above. Optionally, the kits will
further include packaging suitable for containing the catheter and
the instructions for use. Exemplary containers include pouches,
trays, boxes, tubes, and the like. The instructions for use may be
provided on a separate sheet of paper or other medium. Optionally,
the instructions may be printed in whole or in part on the
packaging. Usually, at least the catheter will be provided in a
sterilized condition. Other kit components, such as a guidewire,
may also be included.
[0012] A further understanding of the nature and advantages of the
invention will become apparent by reference to the remaining
portions of the specification and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a perspective view of an atherectomy catheter
constructed in accordance with the principles of the present
invention.
[0014] FIGS. 2-4 show various embodiments of a material capture
device and a material cutting element according to the present
invention.
[0015] FIGS. 5A-5C illustrate a material cutting sequence using one
embodiment of a material capture device and material cutting
element according to the present invention.
[0016] FIGS. 6A-6B show cross-sectional views of a further
embodiment of a material capture device and material cutting
element.
[0017] FIGS. 7-8 show still further embodiments of a material
capture device and material cutting element.
[0018] FIGS. 9-11 show cross-sectional views of a preferred
embodiment of the material capture device;
[0019] FIGS. 12, 13, 14, 14A-C, and 15 show alternative embodiments
of the device show in FIGS. 9-11.
[0020] FIGS. 16-18 depict various embodiments of a cam surface
according to the present invention.
[0021] FIGS. 19-22 are cross-sectional views of a telescoping
cutter having a material capture device according to the present
invention.
[0022] FIGS. 23-24 show a still further embodiment of the material
capture device.
[0023] FIG. 25 shows a kit according to the present invention.
[0024] FIGS. 26 and 27 illustrate a catheter having material
capture devices and material cutting elements oriented at various
angles on the catheter body.
[0025] FIG. 28 shows a preferred embodiment of the present
invention for use with a material imaging device according to the
present invention.
DESCRIPTION OF THE SPECIFIC EMBODIMENTS
[0026] The present invention provides devices, methods, and kits
for use in removing material from a body lumen. The present
invention may be used in a variety of body lumens, including but
not limited to coronary and other arteries. Advantageously, the
present invention reduces the amount of force required to cut
material and facilitates material capture into apertures of the
catheter.
[0027] Apparatus according to the present invention will comprise
catheters having catheter bodies adapted for intraluminal
introduction to the target body lumen. The dimensions and other
physical characteristics of the catheter bodies will vary
significantly depending on the body lumen which is to be accessed.
In the exemplary case of atherectomy catheters intended for
intravascular introduction, the catheter bodies will typically be
very flexible and suitable for introduction over a guidewire to a
target site within the vasculature. In particular, catheters can be
intended for "over-the-wire" introduction when a guidewire lumen
extends fully through the catheter body or for "rapid exchange"
introduction where the guidewire lumen extends only through a
distal portion of the catheter body.
[0028] Catheter bodies intended for intravascular introduction will
typically have a length in the range from 50 cm to 200 cm and an
outer diameter in the range from 1 French (0.33 mm; Fr.) to 12 Fr.,
usually from 3 Fr. to 9 Fr. In the case of coronary catheters, the
length is typically in the range from 125 to 200 cm, the diameter
is preferably below 8 Fr., more preferably below 7 Fr., and most
preferably in the range from 2 Fr. to 7 Fr. Catheter bodies will
typically be composed of an organic polymer which is fabricated by
conventional extrusion techniques. Suitable polymers include
polyvinylchloride, polyurethanes, polyesters,
polytetrafluoroethylenes (PTFE), silicone rubbers, natural rubbers,
and the like. Optionally, the catheter body may be reinforced with
braid, helical wires, axial filaments, or the like, in order to
increase rotational strength, column strength, toughness,
pushability, and the like. Suitable catheter bodies may be formed
by extrusion, with one or more lumens being provided when desired.
The catheter diameter can be modified by heat expansion and
shrinkage using conventional techniques. The resulting catheters
will thus be suitable for introduction to the vascular system,
often the coronary arteries, by conventional techniques.
[0029] The cutting blades used in the present invention will
usually be formed from a metal, but could also be formed from hard
plastics, ceramics, or composites of two or more materials, which
can be honed or otherwise formed into the desired cutting edge. In
the exemplary embodiments, the cutting blades are formed as coaxial
tubular blades with the cutting edges defined in aligned apertures
therein. It will be appreciated that the present invention is not
limited to such preferred cutting blade assemblies, in a variety of
other designs, such as the use of wiper blades, scissor blades or
the like. Optionally, the cutting edge of either or both the blades
may be hardened, e.g., by application of a coating. A preferred
coating material is titanium nitride, available from Brycoat, Inc.,
which may be applied according to manufacturer's instructions.
[0030] Referring now to FIG. 1, a catheter 10 constructed in
accordance with the principles of the present invention comprises a
catheter body 12 having a proximal end 14 and a distal end 16. A
cutting mechanism 18 comprises an outer cutter 20, an inner cutter
22 is attached to the distal end of the catheter body 12, and a
needle 23 as a material capture device. An atraumatic tip 24 is
attached to the distal end of the outer cutter 20, and a guidewire
lumen 25 extends through the entire catheter body, cutting
mechanism 18, and terminates in port 25 at the distal tip of tip
section 24. A proximal hub 30 is attached to the proximal end of
catheter body 12 and comprises a perfusion/aspiration connector 32,
a guidewire connector 34, and a slider 36. The slider 36 is
attached to the proximal end of an actuator rod 37 which extends
from the hub 30 through the lumen of catheter body 12 into the
cutting mechanism 18 where it is attached at a proximal end of the
inner cutter 22. In this way, manual actuation of slider 36 in the
direction of arrow 38 moves inner cutter 22 in the direction of
arrow 40.
[0031] Referring to FIGS. 2A and 2B, this embodiment of the
catheter 10 uses the material capture needle 23 to capture the
material and tension it towards the cutters 20 and 22. The material
capture needle 23 follows a path where the material capture needle
extends outwardly from the catheter body and moves inwardly towards
the catheter body to tension the material. In this embodiment, when
the material capture needle 23 is deployed, it angles out from the
aperture 42 and a portion of the material capture needle typically
runs parallel to the window with the sharpened tip located near the
proximal end of the aperture. The inner cutter or cutting element
22 is reciprocated to open and close the aperture 42 formed in the
wall of the catheter body 12. Movement of the inner cutter 22 also
controls the deployment of the material capture needle. When the
inner cutter 22 opens the aperture 42, the material capture needle
23 is biased outwardly from the catheter body 12. The material
capture needle 23 is preferably spring-loaded, where in its resting
condition, the material capture needle extends outwardly from the
catheter body 12. The material capture needle 23 is otherwise
constrained within the catheter body 12 when the inner cutter 22
closes aperture 42. The material capture needle 23 may be made of a
variety of materials such as stainless steel or a superelastic
material.
[0032] With the material capture needle 23 deployed as shown in
FIG. 2B, the material capture needle may penetrate into the
material when the catheter body 12 is pulled in the proximal
direction. The inner cutter 22 is then closed, as indicated by
arrow 40, to push the material capture needle 23 towards the
catheter body 12 as indicated by arrow 44. Preferably, closing of
cutter 22 will tension the material and draw it into the catheter
body 12 when the cutters 20 and 22 will shear off the material. It
is also preferred that the inner cutter 22, upon finishing the
closing motion, will wipe the piece of cut-off material off the
material capture needle 23 and into the catheter for storage. The
material capture needle 23 and cutting mechanism 18 may then be
readied to make a subsequent cut. The material capture needle 23
typically has a diameter between about 0.1 to 0.5 mm, preferably
0.2 to 0.3 mm, with a length between about 1 to 5 mm, preferably 3
to 4 mm.
[0033] Referring to FIGS. 3-4, a variety of catheter embodiments
may incorporate a needle as a material capture device. Like the
catheter of FIG. 2, these catheters rely on the motion of a cutter
to control positioning of the material capture needle during
cutting. The FIGS. 3A-3B show the distal portion of a catheter 50
having an outer cutter 52 which reciprocates to control the
deployment of the material capture needle 54. Additionally, in this
embodiment, the material capture needle 54 is deployed to have a
forward pointing sharpened tip. With the material capture needle 54
deployed, the catheter 50 would be pushed forward as indicated by
arrow 56 to penetrate target material T. The catheter 50 may also
incorporate a ski mechanism 58 to urge the cutting side of the
catheter radially against the target material T. Such a ski
mechanism is described in detail in commonly assigned, copending
U.S. patent application Ser. No. 08/982,231 (Attorney Docket No.
18489-000200) filed Dec. 17, 1997, the full disclosure of which is
incorporated herein by reference. All of the catheter structures
herein may optionally employ such mechanisms.
[0034] FIGS. 4A and 4B show a catheter 70 having a telescoping
cutter 72 for use with a material capture needle 74. The
telescoping cutter 72 is used to decrease the rigid length of the
catheter 70 and may be used to create a larger window or aperture
76 for removing greater amounts of material. As the telescoping
cutter 72 is drawn proximally, the material capture needle 74 will
be pushed into the aperture 76 as indicated by arrow 78, along with
material attached to the material capture needle. As seen in FIG.
4B, the material capture device 74 may also include one or more
barbs 79 which keep the material from sliding off once it is
excised.
[0035] The catheter 70 is quite useful and an improvement over
conventional atherectomy catheters even without incorporation of
the material capture needle 74. The decrease in the rigid length of
the distal portion of catheter 70 is a significant advantage,
particularly when the catheter is introduced to the highly tortuous
regions of the coronary vasculature. Once at a desired location,
however, the rigid cutter portion of the catheter can be extended
in length by 50% or more, with a theoretical limit of 100% for a
two-portion telescoping region. In the illustrated embodiment, the
cutting aperture 76 is defined only on one of the cutter blades. In
other embodiments, it will possible to define the aperture on both
of the cutting blades and/or in a variety of configurations. While
the cutting blades will preferably employ the cutting edges at each
end, the advantages of the telescoping cutter can be enjoyed even
without the cutting edges.
[0036] Referring now to FIGS. 5A-5C, another embodiment of an
atherectomy catheter 100 uses a material capture needle 102 which
rotates about a pivot pin 104. As indicated by arrow 106 in FIG.
5A, the material capture needle 102 will rotate upward as the
drawbar 108 is pulled proximally. As seen in the cross-section of
FIG. 5B, the drawbar 108 is coupled to slider 110 which has cutting
blade 112. A cam 106 about the pivot pin 104 will pull against the
material capture needle 102 as drawbar 108 is moved. The drawbar
108 will be retracted until the blade 112, as shown in FIG. 5C, has
sheared off any material captured by the material capture needle
102.
[0037] FIGS. 6A and 6B show a catheter embodiment similar to that
of FIGS. 5A-5C. The material capture needle 120 of FIG. 6A rotates
about a pivot 122 to engage material M to be excised from the
luminal wall. The needle actuator for this embodiment differs from
that of catheter 100. The material capture needle 120 of the
present embodiment sits between tabs 124 and 126 which are attached
to the drawbar 130. The drawbar 130 rotates the needle 120 while
pulling on slider 132 having blade 134. Of course, it should be
understood that the motion of the pivoting material capture needle
120 may be dependent or independent of the motion of the cutting
element or blade 134. The material capture needle 120 may also be
constructed of existing devices such as a suture needle used in
procedures such as coronary anastomoses.
[0038] FIG. 7 shows a material capture needle 150 mounted on a base
152 which slides within elongate slots or grooves 154 and 156. The
slots 154 and 156 guide the needle 150 along a path that carries
the needle outward and then inwardly towards the catheter body 158
after the needle has engaged the catheter body. The inner cutter
160 has a cut-out 162 which holds the base 152 as the cutter is
moved with the material capture needle 150. The base may move
vertically within the cut-out 162 to follow the slots 154 and
156.
[0039] In a still further embodiment of the cutting mechanism, FIG.
8 shows a cutter 170 which is controlled by a drawbar 172 which is
separate from the material capture needles 180 and drawbar 182. The
material capture needles 180 continue to pivot as indicated by
arrows 184. Pulling of the cutter drawbar 172 will reciprocate the
cutter 170 without interacting with the positioning of the material
capture needle 180. Such separate control may be desirable in
particular situations where the timing of the engagement of the
material capture needle 180 and the cutter 170 must be more
accurately controlled.
[0040] Referring now to FIG. 9, a preferred embodiment of the
present invention having a material capture device will now be
described in further detail. FIG. 9 shows an inner cutter 200
mounted coaxially within an outer cutter 202 and in a fully distal
position to open the window 204. The material capture device in
this embodiment comprises a penetrating member 206 and a cam
surface 208. The penetrating member 206 is pivotably mounted on the
inner cutter about a pivot pin 210. The penetrating member 206 has
a curved surface 212 that is designed to slide over the cam surface
208. The curved surface 212 is typically a lower or underside
surface of the penetrating member 206. As the inner cutter 200 is
advanced during the cutting motion, the cam surface 208 will guide
the penetrating member 206 in a radially outward direction along a
path that brings the member into engagement with targeted material.
By varying the shape of the curved surface 212 and the height of
the cam surface 208, the penetrating member 206 may have a variety
of material-engaging positions, e.g., where the sharpened tip 214
extends radially beyond the outer diameter of the outer cutter 202,
where the sharpened tip 214 is radially aligned with the outer
diameter of the outer cutter or the inner cutter 200, or where the
tip 214 is within the inner cutter. It should be understood that
the curved surface 212 may be also contain longitudinal grooves and
be contoured as desired to best follow and maintain contact with
the cam surface 208 during the cutting motion. As shown in FIG. 9,
the penetrating member 206 includes a lower protrusion 216 which
helps move tissue proximally away from the cutters after the tissue
has been excised.
[0041] Referring now to FIG. 10, a drive wire 220 mounted within a
drive tube 222 is used to move the inner cutter 200 from a first,
open position to a second, closed position. Of course, other
push/pull elements or separate push elements and pull elements may
be used to control the movement of the inner cutter 200. The drive
wire 220 may be made of material such as stainless steel or nickel
titanium. The drive tube 222 may also be made of a variety of
materials such as a polymer like polyimide, polyurethane, or
polyethylene or a flexible metal such as nickel titanium. The drive
tube 222 may also be made from a composite of metal and polymer, or
a metal that has material selectively removed to increase its
flexibility. Further details of the drive tube can be found in
commonly assigned, copending U.S. patent application Ser. No.
08/982,231 (Attorney Docket No. 18489-000200US), filed on Dec. 17,
1997, the full disclosure of which is incorporated herein by
reference.
[0042] As seen in FIGS. 10 and 11, the cam surface 208 is fixedly
secured to the outer cutter 202 and remains stationary relative to
the penetrating member 206 during the cutting motion. The inner
cutter 200 typically includes a slot or cut-out portion to
accommodate the cam surface 208. Movement of the inner cutter 200
brings the sharpened end 214 into contact with target material
which is pushed towards the first blade 224 (FIG. 10). Referring
now to FIG. 11 as the window 204 is closed, a second blade 226 on
the inner cutter 200 will complete the cutting motion by shearing
off the material against the first blade 224. The cam surface 208
will push against the lower surface 212 of the penetrating member
206 and force the sharpened tip 214 of the penetrating member to
retract into the inner cutter as shown in FIG. 11.
[0043] Referring now to FIGS. 12-14, other embodiments of the
penetrating member, cam surface, and inner cutter will now be
described. FIG. 12 shows an embodiment of the penetrating member
230 where the member has a more aggressively designed sharpened tip
232. The additional length of the tip 232 allows the penetrating
member 230 to engage materials further away from the outer cutter
202. The lower surface 234 of the penetrating member 230 includes a
recessed portion 236 that allows the penetrating member to be
retracted into the outer cutter 202 when the inner cutter 200 is in
its distal most position.
[0044] FIG. 13 shows a material capture device where the sharpened
tip 240 of the penetrating member 242 is even with the outer
diameter of the outer cutter 202 when the penetrating member is in
its tissue-engaging position. The cam surface 244 has a decreased
height and the location of the pivot pin 246 has also been lowered
to change the position of the sharpened tip 240. The extension
distance may vary depending on the desired function of the cutter.
For example, the extension distance of the penetrating member
(where the outer edge of the inner cutter is 0.000) may range
between about-0.05 to 0.10 inches (as shown in phantom), preferably
between about 0.00 to 0.04 inches, and most preferably between
about 0.01 to 0.02 inches for a 0.100 maximum diameter cutter. The
length of the sharpened tip 240 may also be used to change the
maximum extension distance of the material capture device.
[0045] FIG. 14 shows an embodiment of the penetrating member 250
used with a reduced length inner cutter 252. Using a shorter inner
cutter 252 can reduce the rigid length of the catheter and improve
tracking of the catheter through tortuous vasculature. Unlike the
inner cutters shown in FIGS. 9-11, the inner cutter 252 in FIG. 14
has the side-opening aperture 254 located at the proximal end of
the cutter. In other embodiments, this side-opening aperture is
located away from the ends of the cutter. Moving the aperture 254
to the end of the cutter 252 allows the reduction in rigid length.
In this embodiment, the drive wire 220 is repositioned to be on the
lower surface of the inner cutter 252.
[0046] The embodiments of FIGS. 12-14 may further be provided with
positioner wires as shown in FIGS. 14A-14C. The cutter mechanism
500 comprises a penetrating member 502, an inner cutter 504, an
outer tubular cutter 506, and a pair of positioner wires 510 (only
one of which is visible in the figures). The inner cutter 504 is
shown in if its closed (fully proximally advanced) configuration in
FIG. 14A. The penetrating member 502 is fully radially retracted
within the cutter assembly, and the positioning wires are also
fully retracted.
[0047] The positioning wires 510 form from a resilient material,
typically stainless steel ribbon or a shape memory alloy ribbon,
such as nitinol. The proximal ends of each wire are attached in
slots formed near the proximal end of the outer tubular cutter 506
and extend inwardly through openings (not shown) so that their
distal ends extend radially inwardly into the interior of the outer
tubular cutter, as shown in the left-hand side of FIG. 14A. With
the inner cutter 504 closed, as shown in FIG. 14A, the cutter
mechanism 500 can be advanced through the vasculature with a
minimum profile, i.e., neither the tissue-penetrating member 502
nor the positioner wires 510 extend out from the cutter
mechanism.
[0048] Once positioned at the treatment location, the inner cutting
blade 504 may be distally retracted, both opening a cutter window
514 and causing the cam surface 518 on the penetrating member 502
to engage a cam element 520, causing the penetrating tip of the
penetrating element 502 to emerge through the cutter window 514 as
generally described with the embodiments of FIGS. 12-14. Cutter
mechanism 500 differs from the earlier embodiments in that a lower
portion of the inner cutter 504 engages the curved distal ends 522
of the positioner wires 510, as best seen in FIG. 14B. In
particular, as the inner cutter 504 moves in a distal direction,
(i.e., toward the left in FIGS. 14A-14C), it depresses the curved
ends 522, causing the main body of the positioner wires 510 to
emerge from the outer cutter 506, as indicated at 530 in FIG. 14B.
As the inner cutter 504 moves further in the distal direction, the
positioner wires 510 are deployed fully outwardly, as best shown in
FIG. 14C. The cutter window 514 is fully opened and the penetrating
member 502 again retracted within the cutter mechanism 500. With
the positioner wires 510 fully deployed, the penetrating member 502
of the cutter mechanism is disposed to penetrate into target tissue
as the inner cutter member 504 is closed in the proximal direction.
Preferably, the positioner wires 510 will apply a very low amount
of force against the artery wall since the penetrating member 502
will be able to quickly engage and capture the tissue to be cut by
the mechanism 500. Additionally, if the lesion being treated has a
small diameter, the positioner wires will simply fold over as the
inner cutter is moved distally to open the cutter window 514.
During the cutting operation, the positioner wires 510 will quickly
spring back into the outer tubular cutter 506 since the
tissue-penetrating member will act to maintain contact with the
material to be cut during the remainder of the cutting
operation.
[0049] FIGS. 15-18 show a still further embodiment of the material
capture device using a penetrating member and a cam surface. In
FIG. 15, the penetrating member comprise a curved needle 260 which
is fixedly secured to the inner cutter 200 and biased against a cam
surface 262. The curved needle 260 may be integrally formed with
the inner cutter 200 or otherwise attached such as by welding or
other methods known in the art. As the inner cutter 200 is
advanced, the cam surface 262 will guide the needle 260 along a
path outwardly to engage target material and then it back towards
the catheter body. As discussed previously, the needle 260 need not
move beyond the outer cutter 202, instead remaining even with the
outer diameter of the outer cutter as the needle engages material.
The inner cutter 200 may also include a material imaging device 264
such as an ultrasound transducer or optical fibers which will image
tissue when the window 204 is closed by the cutter. The optical
fibers may be used for optical coherence tomography or optical
coherence reflectometry. A suitable ultrasound transducer or
transducer array may be found in commonly assigned, copending U.S.
patent application Ser. No. 09/____ (Attorney Docket No.
18489-001000US), filed ______, the full disclosure of which is
incorporated herein by reference.
[0050] FIGS. 16-18 shows various embodiments of the cam surface
262. FIG. 16 shows a perspective view of the cam surface 262 used
in the device of FIG. 15. FIGS. 17 and 18 show a cam surface 270
which has separate tracks 272 and 274 which can guide the needle
260 along different needle paths when the needle is advanced and
when the needle is retracted. The cam surface 270 has funneled
portions 276 and 278 for guiding the needle into the respective
tracks 272 and 274, depending on whether the needle is being
advanced or retracted.
[0051] Referring now to FIGS. 19-22, a telescoping cutting device
using a material capture device will be described in further
detail. As shown in FIG. 19, the telescoping portion 300 in this
embodiment of the cutting device extends outwardly from an aperture
302 on the catheter body 304. The catheter body 304 may include a
cutting blade 305 for shearing material drawn into the cutting
device. It should be understood, of course, that the blade may be
located in a variety of positions such as on the telescoping
portion 300 of the device or located on both the telescoping
portion and the catheter body. As shown in FIG. 19, the distal end
306 of the telescoping portion 300 is preferably adapted to mount a
soft, atraumatic distal tip (shown in phantom) to facilitate
passage of the device through body lumens. The tip may, in some
embodiments, be integrally formed with the telescoping portion
300.
[0052] As seen in FIG. 19, the telescoping portion 300 is in a
distal position where one edge 307 of the telescoping portion is
spaced apart from the catheter body and defines a cutting window
308. In some embodiments, the edge 307 may comprise a cutting blade
while in other embodiments the edge may be unsharpened, but pushing
material into the cutting window. The cutting window 308 is
preferably a directional cutting window which may open towards one
side of the catheter where material may intrude to be cut off. A
penetrating member 310 is preferably rotatably mounted about a
pivot pin 312 on the telescoping portion 300 to engage the
material. It should be understood that some embodiments of the
telescoping portion 300 may not include the penetrating member 310.
The penetrating member 310 is shown in FIG. 19 to be in a first,
tissue-engaging position. A tether or leash element 314 is
rotatably coupled to the penetrating member 310 and can be pulled
proximally as indicated by arrow 316 to rotate the member into the
tissue-engaging position. The tether 314 may be made of a variety
of materials such as stainless steel or a polymer like polyimide or
a fibrous material like Kevlar.RTM..
[0053] FIG. 20 shows the telescoping portion 300 being retracted by
a drive wire 318 as indicated by arrow 320. As one end of the
penetrating member 310 contacts abutment or deflection block 322,
the penetrating member 310 will begin to rotate as indicated by
arrow 324. Further retraction of the telescoping portion 300 will
cause the sharpened tip 326 of the penetrating member 310 to be
pushed within the boundaries of the catheter body. As seen in FIG.
21, the penetrating member 310 and telescoping portion 300 may be
substantially retracted into the catheter body 304. The tether 314
has a bent portion 330 that allows the penetrating member to
rotated to the position shown in FIG. 22. Retraction of the
penetrating member 310 into the catheter body as shown in FIG. 22
also functions to push tissue proximally into the catheter body
where it can be stored.
[0054] Referring now to FIGS. 23 and 24, a still further embodiment
of the tissue capture device will be described. FIG. 23 shows a
penetrating member 340 that is rotatably mounted to the outer
cutter 342, instead of the inner, slidable cutter 344 as shown in
previous embodiments. The inner cutter 344 can be reciprocated to
cut off materials captured in the window 346. The inner cutter 344
includes a pushing element 348 that contacts the penetrating member
340 to rotate the penetrating member into the target material and
then return to the inside of the outer cutter 342. The pushing
element 348 traverses over the top of the surface of the
penetrating member and wipes off any tissue, directing it into the
catheter. The penetrating member 340 may be reset to its starting
position by a variety of methods such as through the use of a leash
element as described above or by using a bias element to create a
return force.
[0055] Referring now to FIG. 25, the present invention will further
comprise kits including catheters 400, instructions for use 402,
and packages 404. Catheters 400 will generally be described above,
and the instruction for use (IFU) 402 will set forth any of the
methods described above. Package 404 may be any conventional
medical device packaging, including pouches, trays, boxes, tubes,
or the like. The instructions for use 402 will usually be printed
on a separate piece of paper, but may also be printed in whole or
in part on a portion of the packaging 404.
[0056] While all the above is a complete description of the
preferred embodiments of the inventions, various alternatives,
modifications, and equivalents may be used. For example, the
cutters and material capture devices may be oriented in a variety
of angles on the catheter body. As seen in FIGS. 26 and 27, the
catheters 430 and 440 have cutters 432 and 442 which are oriented
perpendicularly or at other inclined angles to a longitudinal axis
450 of the catheter. A plurality of material capture devices may be
used with a single or a plurality of cutting blades. Additionally,
as discussed above for FIG. 15, another embodiment of the device
includes an ultrasound transducer 460 as shown in FIG. 28. In place
of an ultrasonic transducer, the device may use one or more optical
fibers for optical coherence tomography or optical coherence
reflectometry. Although the foregoing invention has been described
in detail for purposes of clarity of understanding, it will be
obvious that certain modifications may be practiced within the
scope of the appended claims.
* * * * *