U.S. patent application number 09/377894 was filed with the patent office on 2002-01-24 for apparatus and methods for removing material from a body lumen.
Invention is credited to BOYD, STEPHEN, FOLLMER, BRETT, WILLIS, ERIC.
Application Number | 20020010483 09/377894 |
Document ID | / |
Family ID | 23490944 |
Filed Date | 2002-01-24 |
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
|
Family ID: |
23490944 |
Appl. No.: |
09/377894 |
Filed: |
August 19, 1999 |
Current U.S.
Class: |
606/159 |
Current CPC
Class: |
A61B 10/06 20130101;
A61B 17/320783 20130101; A61B 17/32075 20130101; A61B 2017/003
20130101; A61B 2017/320791 20130101; A61B 17/3207 20130101 |
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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