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| United States Patent Application |
20020010483
|
| Kind Code
|
A1
|
|
FOLLMER, BRETT
;   et al.
|
January 24, 2002
|
APPARATUS AND METHODS FOR REMOVING MATERIAL FROM A BODY LUMEN
Abstract
Devices, methods, and kits for removing material from a body lumen. The
devices and methods may be used in a variety of body lumens, including
but not limited to coronary arteries and other blood vessels. In general,
the device or catheter has a scoop-shaped cutting blade mounted on a
catheter body for removing material from a body lumen. The cutting blade
has a cutting edge that travels a curved path about a pivot point of the
blade, preferably moving in an outward direction from the catheter body
to engage the target material for removal. The scoop-shaped blade has a
collection surface located behind the cutting edge to collect material
removed from said body lumen.. Advantageously, a scoop-shaped cutting
blade according to the present invention facilitates material engagement
and the collection surface may be used to bring material back into the
catheter body as the blade begins to part-off material. The cutting blade
is usually mounted to move in an inward direction towards the catheter
body after the cutting edge has engaged the material. The cutting blade
can also more easily engage occlusive material that is compressed against
the body lumen wall.
| Inventors: |
FOLLMER, BRETT; (SANTA CLARA, CA)
; BOYD, STEPHEN; (MOSS BEACH, CA)
; WILLIS, ERIC; (SANTA CRUZ, CA)
|
| Correspondence Address:
|
TOWNSEND AND TOWNSEND AND CREW
TWO EMBARCADERO CENTER
EIGHTH FLOOR
SAN FRANCISCO
CA
94111-3834
US
|
| Serial No.:
|
377894 |
| Series Code:
|
09
|
| Filed:
|
August 19, 1999 |
| Current U.S. Class: |
606/159 |
| Class at Publication: |
606/159 |
| International Class: |
A61B 017/22 |
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; and a
scoop-shaped cutting blade mounted on the catheter body, said cutting
blade having a cutting edge and a material collection surface; wherein
said cutting is configured to travel along a curved path about a pivot
point of said cutting blade and wherein said material collection surface
is located behind said cutting edge to urge material removed from said
body lumen towards the catheter body.
2. A catheter as in claim 1 wherein said cutting edge is mounted to move
along a portion of said path in an outward direction from the catheter
body to engage said material.
3. A catheter as in claim 1 wherein said cutting edge of the cutting blade
is mounted to move in an inward direction towards said catheter body
after said cutting edge has engaged said material.
4. A catheter as in claim 1 wherein said material collection surface
comprises a concave surface.
5. A catheter as in claim 1 wherein said cutting blade comprises a sphere
having an opening wherein an edge of the opening defines the cutting
edge.
6. A catheter as in claim 1 wherein said cutting blade is mounted on said
catheter body to reciprocate along a longitudinal path on said catheter
body.
7. A catheter as in claim 6 wherein said cutting blade use a guide for
defining said longitudinal path, said guide selected from the group
consisting of a slotted track, a rail, or a ramp on said catheter body.
8. A catheter as in claim 6 wherein said cutting blade is mounted to
reciprocate along said longitudinal path between a first position placing
said cutting edge outside of said catheter body and a second position
placing said cutting edge substantially within said catheter body.
9. A catheter as in claim 1 wherein said cutting blade is mounted on said
catheter body to rotate about an axis perpendicular to a longitudinal
axis of said catheter body.
10. A catheter as in claim 1 wherein said cutting blade includes a
material engaging member mounted on said cutting blade to engage said
material before said cutting edge contacts said material.
11. A catheter as in claim 1 wherein said cutting blade includes at least
one penetrating point mounted on said cutting blade to engage said
material before said cutting edge contacts said material.
12. A catheter as in claim 1 further comprising a second cutter mounted on
said catheter body to assist said cutting edge of the cutting blade in
partingoff of material.
13. A catheter as in claim 1 further comprising an actuator within said
catheter body to move the cutting blade along said curved path.
14. A catheter as in claim 13 wherein said actuator comprises a pullwire
coupled to said cutting blade.
15. A catheter as in claim 1 wherein said catheter body comprises a
catheter wall with an opening from which said cutting blade extends to
engage material.
16. A catheter as in claim 1 wherein said catheter body has a distal,
forward facing opening from which said cutting blade extends to engage
material.
17. A catheter as in claim 1 wherein the catheter body comprises an
atraumatic, tapered distal end with a forward facing opening at said
distal end.
18. A catheter as in claim 1 wherein said catheter body has a shaft
adaptor at said proximal end.
19. A catheter as in claim 1 wherein said catheter body comprises a
cutting mechanism, said cutting blade mounted on said cutting mechanism.
20. An atherectomy catheter comprising: a catheter body having a proximal
end and a distal end; a cutting mechanism mounted on said distal end of
the catheter body; and cutting means rotatably mounted on said cutting
mechanism for removing material from a body lumen.
21. A catheter as in claim 20 wherein said cutting means comprises a
scoop-shaped cutting blade having a cutting edge mounted to move along a
curved path about a pivot point of said cutting blade.
22. A catheter as in claim 21 wherein said cutting blade includes a
collection surface located behind said cutting edge in the cutting
direction.
23. A catheter as in claim 21 wherein said cutting blade is mounted to
move in an outward direction from the catheter body for a portion of said
curved path.
24. A method for removing material from a body lumen, the method
comprising: positioning a catheter body having a scoop-shaped cutting
blade adjacent to said target material in the body lumen, said cutting
blade having a cutting edge and a material collection surface; and
rotating said cutting blade about a pivot point to engage and cut said
target material while urging the material into the catheter body with
said material collection surface.
25. A method as in claim 24 further comprising reciprocating said cutting
blade along a longitudinal path on said catheter body to remove material.
26. A method as in claim 25 wherein said reciprocating of said cutting
blade along said longitudinal path occurs while said cutting blade is
being rotated.
27. A method as in claim 25 wherein said longitudinal moving step
reciprocates the cutting blade between a first position where the cutting
edge is outside the catheter body and a second position wherein the
cutting edge is within the catheter body.
28. A method as in claim 25 further comprising piercing said material with
a penetrating member in advance of engaging the material with said
cutting edge.
29. A method as in claim 25 wherein said rotating of the cutting blade
brings the cutting edge adjacent to a second cutting edge of a second
cutter.
30. A method as in claim 29 wherein said second cutter is mounted on said
catheter body.
31. A kit comprising: a catheter having a scoop-shaped cutting blade;
instructions for use in removing material from a body lumen comprising
positioning said catheter adjacent to said material in the body lumen,
said cutting blade having a cutting edge and a material collection
surface, and rotating said cutting blade about a pivot point to engage
and cut said material while urging the material into the catheter body
with said material collection surface; 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,
sidecutting 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 successful in
treating many types of atherosclerosis, known catheter designs may be
improved to farther enhanced performance. For example, many known
side-cutting atherectomy catheters have difficulty in capturing occluding
material in the cutting aperture. Conventional atherectomy catheters
typically use cutters mounted within openings on the sidewall of the
catheter body. Some of these conventional catheters are difficult to
position in the body lumen to engage the target tissue or material with
these sidewall openings since the catheter must typically be positioned
so that material will intrude into the opening. This may make it
difficult to remove certain types of obstructions which do not lend
themselves to being received in the catheter aperture. Furthermore,
catheters which require material to intrude into the catheter aperture
limit the aggressiveness with which materials can be removed in severe
occlusion type blockages. Additionally, it is often difficult for
conventional atherectomy cutters to apply the requisite pressure to cut
off the targeted tissue or 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 and parting-off of occlusive
material. It would also be particularly desirable to have catheters which
can remove occlusive material located near the catheter but do not
intrude into the catheter aperture. 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 devices, methods, and kits for
removing material from a body lumen. The catheters and methods of the
present invention may be used in a variety of body lumens, including but
not limited to coronary arteries and other blood vessels. In general, a
catheter of the present invention has a scoop-shaped cutting blade
mounted on a catheter body for removing material from a body lumen. The
cutting blade has a cutting edge that travels a curved path about a pivot
point of the blade, preferably moving in an outward direction from the
catheter body to engage the target material for removal. The scoop-shaped
blade has a collection surface located behind the cutting edge to collect
material removed from said body lumen. Advantageously, a scoop-shaped
cutting blade according to the present invention facilitates material
engagement, and the collection surface may be used to bring material back
into the catheter body as the blade begins to part-off material. The
cutting blade is usually mounted to move in an inward direction towards
the catheter body after the cutting edge has engaged the material. The
scoop-shaped cutting blade can also more easily engage occlusive material
that is compressed against the body lumen wall since the blade may be
mounted to extend outward from 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 will include mechanisms for engaging cutting blades against
selected portions of a vascular wall. Optionally, the catheter should
permit blood perfusion during performance of an atherectomy procedure.
Preferably, but not necessarily, the cutting edge of the cutting blade
will extend outside of the catheter body to engage material in a body
lumen. Typically, the cutting blade rotates to place the cutting edge in
the desired position. The arc defined by the rotation of the cutting
blade is usually large enough to place the cutting edge outside the
boundaries of the catheter body. The aperture from which the cutting
blade extends may be located at a variety of positions on the catheter
body, such as along the sidewall of the catheter or at the distal end of
the catheter body. Devices having the cutting blade located at the distal
end of the catheter may be used to bore through material in a
substantially occluded body lumen. Preferably, the cutting blade has a
mating surface on the catheter body to assist in the parting-off or
cutting of material.
[0008] According to the present invention, embodiments of the catheter may
have a scoop-shaped cutting blade that reciprocates longitudinally along
a guide, such as a slotted track, a rail, or a ramp, to a position
outside the catheter body. Furthermore, the cutting blade may be rotated
about its pivot point while the blade is reciprocated longitudinally. A
cutting blade that travels longitudinally while rotating about its pivot
point can simulate the movement of a surgical curette/bone scraping
device to remove greater amounts of material from the body lumen.
Advantageously, such a rotating and translating motion may allow the
catheter to lie stationary in the body lumen while the cutting blade
travels out from the catheter body to grab material and return towards
the catheter body to part it off. Rotation and translation also allows
material to be removed and collected in a simultaneous manner. Rotation
of the cutting blade may also increase the amount of force that may be
applied against the material (since both translational and rotational
force may be applied). The cutting blades used on the present invention
may also include needles or other sharpened points to penetrate into the
material to grasp the material before it is parted off.
[0009] In another aspect of the present invention, a method is provided
for excising occlusive material from within a body lumen. The method
comprises positioning a catheter body having a scoop-shaped cutting blade
adjacent to a target material in the body lumen. Material may be parted
off from the body lumen by rotating the cutting blade about a pivot point
to engage and cut the target material while urging the material into the
catheter body with a material collection surface on the cutting blade. Of
course, in some embodiments, the cutting blade may translate
longitudinally while being rotated about a pivot point of the cutting
blade. The longitudinal moving step usually involves reciprocating the
cutting blade between a first position where the cutting edge is outside
the catheter body and a second position where the cutting edge is
substantially within the catheter body.
[0010] 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.
[0011] 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
[0012] FIG. 1 is a perspective view of an atherectomy catheter constructed
in accordance with the principles of the present invention.
[0013] FIGS. 2-4 show cross-sectional views of a cutting blade according
to the present invention mounted in the catheter of FIG. 1.
[0014] FIGS. 5-8 show various views a cutting blade according to the
present invention mounted at the distal end of the catheter.
[0015] FIGS. 9-10 are cross-sectional views of a cutting blade which may
rotate and translate longitudinally along the catheter.
[0016] FIGS. 11 - 1 3 depict further embodiments of a cutting blade
according to the present invention which move along a longitudinal path.
[0017] FIGS. 14-17 show a cutting blade of FIG. 9 used to remove material
from a body lumen.
[0018] FIG. 18 shows a kit according to the present invention.
DESCRIPTION OF THE SPECIFIC EMBODIMENTS
[0019] 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 facilitates the
engagement and removal of materials in the body lumen. The invention may
also be adapted to remove larger amounts of material in each cutting
motion.
[0020] 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.
[0021] 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.
[0022] 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 chrome plating. A
preferred chrome plating material is ME-92, available from ME-92
Operations, Inc., which may be applied according to manufacturer's
instructions. Of course, other precision thin-film hard coatings such as
a titanium nitride layer from BryCoat.TM. may be used to engineer the
desired surface properties.
[0023] 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. The catheter body 12
typically includes a cutting mechanism 18 integrally formed with and
considered part of the catheter body. The cutting mechanism 18 may of
course be a separate part which is attached to the distal end of the
catheter body during manufacture. The cutting mechanism 18 comprises a
first cutter 20 and a second cutter 22 that provides a mating surface
against which material may be parted off. The first cutter 20 may be a
scoop-shaped cutting blade that cuts material that is near the vicinity
of the aperture 23. An atraumatic tip 24 is attached to the distal end of
the catheter body, 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 first cutter 20. In this
way, manual actuation of slider 36 in the direction of arrow 38 moves
first cutter 20 in the direction of arrow 40.
[0024] Referring now to FIGS. 2-4, the cutting motion of blade 20 will be
described in detail. In this embodiment of the cutting mechanism 18, the
first cutter or cutting blade 20 is a scoop-shaped cutting blade as seen
in FIG. 2. As the blade 20 rotates through its range of motion, the
cutting edge 50 of the blade will draw an arc (as indicated by the dotted
line 52) that extends outward from the aperture 23 for a portion of the
blade's path. As seen in FIG. 3, this allows the blade 20 to engage
material that has intruded into the aperture 23 or to move outside the
diameter of the catheter to engage those materials in the outward
vicinity of the aperture 23. Some cutting may occur along the cutting
edge 50 as the first blade 20 engages the material M. The parting-off of
the material is usually completed when the cutting edge 50 clears, or in
some cases engages, the mating surface or edge of the second cutter 22 as
shown in FIG. 4.
[0025] A material collection surface 54 is usually located behind the
cutting edge 50 on the cutting blade 20 in the direction of cutting. The
collection surface 54, as shown in FIGS. 3 and 4, will urge material M
towards the interior of the catheter. The collection surface 54 may be
concave or cupped surface which can more easily contain the material M
that is to be parted off. The scoop-shaped cutting blade 20 may assume
various shapes similar to a spoon, a bowl, a shovel blade, a claw, or the
like. The curved shape of the cutting blade 20 allows the blade to be
substantially contained within the catheter during delivery but extend
outside the boundaries of the catheter body to engage material during
cutting.
[0026] The first blade 20 may be actuated in various manners. As shown in
the sequence of FIGS. 2-4, a pullwire 55 is used to rotate the cutting
blade 20 about a pivot point 56. The pivot point 56 may be defined by a
pin passing through the blade 20 or by a protrusion on the blade which
sits in a recess on the body portion of the cutting mechanism. Spring
mechanisms, gears, or various cable-based systems of reduced size may
also be used to rotate the cutting blade 20.
[0027] Referring now to FIGS. 5-8, catheters having cutting blades located
at the distal end of the catheter body will now be described. FIGS. 5 and
6 show catheter 59 having a spherical or "scoop-shaped" cutting blade 60
with a cutting edge 62 that can extend outwardly from an aperture 64
located at the distal end of the catheter. Positioning the cutting blade
60 in this manner allows the catheter to bore through obstructions in the
body lumen. The cutting edge 62 can travel outward towards obstructive
material to engage and then part-off the material. The distal end 66 of
the catheter around the aperture 64 may be swaged to conform to the
curved contours of the cutting blade. This creates an atraumatic outer
surface that would advantageously allow the catheter to remove material
from the center of a tubular body lumen without damaging the wall of the
tubular member. The cutting zone in this embodiment would be spaced apart
from the walls of the tubular body lumen or member. Advantageously, such
a swaged distal end would enable the device to bore into a stenosis
within a stent and not contact the stent struts. Such a device, along
with the embodiment shown in FIGS. 1-5, creates a device having a reduced
rigid length since the rotating scoop-shaped cutter 20 and 60 rely on
rotational instead of translational motion. As seen in FIG. 6, the rigid
length is denoted by bracket 68. Like the device of FIGS. 2-4, a pullwire
70 is used to rotate the cutting blade 60.
[0028] The positioning and exposure of the cutting blade on the distal end
of the catheter may be varied. FIGS. 7 and 8 show that the aperture 100
and the distal end 102 of the catheter may be shaped to facilitate
material removal in a certain direction or for more aggressive material
removal. The aperture 100 in FIGS. 7 and 8 allows for more radial motion
of the cutting blade than the aperture 64 in the device of FIG. 5. The
aperture 100 may allow the device to remove larger amounts of material
with each cutting motion when more aggressive removal is desired. As seen
in FIG. 8, the cutting blade 104 uses a pivot pin or bar 106 to mount the
cutting blade to the distal end 102. The cutting blade 104 works in
conjunction with a second cutting edge 110 which mates with the cutting
edge 112 on the cutting blade. Preferably, the cutting edges 110 and 112
have teeth or penetrating point 114 which can penetrate the material and
allow the cutter to grasp the material and draw it inwards towards the
interior of the catheter. Again, it can be seen that the cutting
mechanism has a reduced rigid length 116 (FIG. 7) allowing the catheter
to navigate body lumens with tortuous configurations.
[0029] In another aspect of the present invention, the spherical or
scoop-shaped cutting blades according to the present invention may be
designed for both translational and rotational motion. Referring now to
FIGS. 9 and 10, one embodiment of a catheter with such a cutting
mechanism will be described. FIG. 9 shows a cutting mechanism 140 mounted
on a catheter 142 via a shaft adaptor 144. The cutting mechanism 140 has
a distal aperture 150 that opens along the side wall of the mechanism and
extends to the forward facing distal end of the mechanism. A cutting
blade 160 is mounted to reciprocate axialy within the aperture 150. The
cutting blade 160 has a stem 162 that slides within a slot 164 along the
wall of the cutting mechanism 140. The stem 162 places limits on the
motion of the cutting blade 160 to create rotational movement of the
cutting blade 160 at the distal-most and proximal-most positions. FIG. 9
shows the blade 160 at a distal-most position while FIG. 10 shows the
cutting blade at a proximal-most position. When the center extension rod
166 pushes the cutting blade 160 past the distal limit of the slot 164,
the cutting blade rotates forward. When the extension rod 166 pulls the
cutting blade 160 past the proximal limit of slot 164, the cutting blade
rotates backwards to complete the cutting motion. Moving the cutting
blade 160 longitudinally along the cutting mechanism increases the amount
of material that can parted off in each stroke of the cutting blade. As
the blade 160 extends outside the aperture 150 when positioned for
cutting, it may also engage material more easily.
[0030] Referring now to FIGS. 11-12, another catheter-mountable cutting
mechanism having a longitudinally reciprocating cutting blade will be
described. FIG. 11 shows a cutting mechanism 200 with a shaft adaptor 202
for coupling with a catheter body. The mechanism 200 has a ball-shaped
cutting blade 210 mounted on a rail 212 that guides the cutting blade
between a first position outside the diameter of the cutting mechanism
(FIG. 11) and a second position substantially within the cutting
mechanism (shown in phantom). By having a cutting blade 210 travel on a
rail and move outside the profile of the cutting mechanism 200 as shown
in FIG. 11, the catheter and cutting mechanism can advantageously lie
stationary while the blade travels outside the mechanism to capture and
part-off material. The cutting blade 210 as shown in FIG. 11 is mounted
with at least one needle 220 for penetrating material. The sharpened end
222 of the needle 220 is preferably located in front of the cutting edge
224 so that the needle can help the cutting blade 210 engage the
material. The blade 210 may be designed to have a plurality of material
penetrating members.
[0031] Referring now to FIGS. 12 and 13, another cutting mechanism with a
longitudinally moving cutting blade will now be described. FIG. 11 shows
a cutting mechanism 230 with a cutting blade 232 mounted in a ball or
scoop 233 that reciprocates along cutter tracks 234 formed in a housing
236. Like the device shown in FIG. 11, the cutting blade 232 travels
outside the diameter of the cutting housing 236 to engage material in the
body lumen. As seen in FIG. 13, the cutting blade 232 may be mounted with
a stem 240 to cause rotation of the cutting blade when it is moved to the
outermost position along the cutter track 234. The cutting blade 232 may
be actuated by various methods such as by pullwires, or the like. For
example, the cutting blade may be actuated by either a central or
off-center pullwire where the slot acts as a travel limit to cause
rotation of the cutting blade at the end of the blade's travel.
[0032] Referring now to FIGS. 14-17, the cutting motion of a translational
and rotational cutting blade as shown in FIG. 9 will be further
described. The cutting blade 260 on the cutting mechanism in FIG. 14 may
be mounted with an articulating or steerable catheter (shown in phantom)
to position the cutting blade as desired. This allows the cutting blade
260 to be more easily positioned against material in the body lumen and
also adjust the direction of material removal. As seen in FIG. 14, the
cutting blade 260 is usually delivered with the cutting blade in a closed
or retracted position. When the cutting mechanism nears the target
material M, the cutting blade is moved to the open position as seen in
FIG. 15. When a steerable or articulating catheter is used, the cutting
mechanism can be angled (FIG. 16) to more aggressively remove material
from the body lumen. The cutting blade 260 will retract and rotate to
part-off the body lumen material (FIG. 17). The cutting blade 260 may
rotate about its pivot point while it is being retracted or at the end of
the retraction. Where the cutting mechanism is mounted on a nonsteerable
catheter, the cutting mechanism may lie substantially parallel against
the body lumen wall, and the cutting blade 260 will move longitudinally
to scrape material from the body lumen wall.
[0033] Referring now to FIG. 18, the present invention will further
comprise kits including catheters 300, instructions for use 302, and
packages 304. Catheters 300 will generally be as described above, and the
instruction for use (IFU) 302 will set forth any of the methods described
above. Package 304 may be any conventional medical device packaging,
including pouches, trays, boxes, tubes, or the like. The instructions for
use 302 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 304.
[0034] 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 cutting blade may be oriented
to cut along a variety of angles relative to the longitudinal axis of the
catheter body. The cutting blade may be adapted for use with a tissue or
material capture device which is located in front of and sometimes spaced
apart from the cutting blade. A suitable capture device is described
further in commonly assigned, copending U.S. application No. 09/______
(Attorney Docket No. 18489-001600U.S.) filed on the same day as the
present application, the full disclosure of which is incorporated herein
by reference. In some embodiments, the scoop-shaped blade may appear
similar to a claw or a shovel. The term "scoop-shaped" as used herein
refers generally to a device that has a cutting edge and a collection
surface. Typically, the collection surface is a concave surface located
behind the cutting edge in the cutting direction. In some alternative
embodiments, the scoop-shaped cutting blade may have adjacent
perpendicular walls to form the collection surface. 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.
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