U.S. patent application number 11/070446 was filed with the patent office on 2005-07-07 for ablation burr.
This patent application is currently assigned to Scimed Life Systems, Inc.. Invention is credited to Barry, Robert, Clement, Tom, Drummond, Denise, Hirst, Paul A., Kadavy, Tom, Kanz, Bill, Swinford, Gary, Wulfman, Edward, Wyzgala, Mark.
Application Number | 20050149084 11/070446 |
Document ID | / |
Family ID | 26758702 |
Filed Date | 2005-07-07 |
United States Patent
Application |
20050149084 |
Kind Code |
A1 |
Kanz, Bill ; et al. |
July 7, 2005 |
Ablation burr
Abstract
A catheter including an elongate drive shaft having a proximal
end and a distal end, an ablation burr disposed at the distal end
expandable between a first position and a second position, wherein
in the second position has a greater transverse dimension than in
the first position. The catheter of the present invention can
include a mechanism for positioning the burr eccentrically within a
vessel lumen. In this context, expansion means that the burr can
ablate a lumen having a larger diameter than the diameter of the
lumen of the guide catheter to which the device is advanced.
Inventors: |
Kanz, Bill; (Sacramento,
CA) ; Drummond, Denise; (North Ogden, UT) ;
Barry, Robert; (Kirkland, WA) ; Hirst, Paul A.;
(Liberty Lake, WA) ; Wyzgala, Mark; (Bellevue,
WA) ; Swinford, Gary; (Issaquah, WA) ;
Wulfman, Edward; (Woodinville, WA) ; Clement,
Tom; (Redmond, WA) ; Kadavy, Tom; (Bellevue,
WA) |
Correspondence
Address: |
CHRISTENSEN, O'CONNOR, JOHNSON, KINDNESS, PLLC
1420 FIFTH AVENUE
SUITE 2800
SEATTLE
WA
98101-2347
US
|
Assignee: |
Scimed Life Systems, Inc.
|
Family ID: |
26758702 |
Appl. No.: |
11/070446 |
Filed: |
March 1, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11070446 |
Mar 1, 2005 |
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10448476 |
May 29, 2003 |
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10448476 |
May 29, 2003 |
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09670416 |
Sep 26, 2000 |
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6596005 |
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09670416 |
Sep 26, 2000 |
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09262502 |
Mar 4, 1999 |
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6146395 |
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60076963 |
Mar 5, 1998 |
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Current U.S.
Class: |
606/159 |
Current CPC
Class: |
A61B 17/320758 20130101;
A61B 2017/320004 20130101; A61B 2017/00867 20130101; A61B 2017/003
20130101; A61B 2017/00557 20130101; A61B 2017/320733 20130101; A61B
17/320725 20130101; A61B 2017/320766 20130101 |
Class at
Publication: |
606/159 |
International
Class: |
A61B 017/22 |
Claims
1-22. (canceled)
23. A catheter assembly, comprising: an elongate drive shaft having
a proximal end and a distal end; and an ablation burr eccentrically
connected to the drive shaft at the distal end thereof.
24. The catheter assembly in accordance with claim 23, further
comprising a counter weight connected to the burr.
25. The catheter assembly in accordance with claim 23, wherein the
burr includes an abrasive surface.
26-31. (canceled)
32. A method of removing lesion material from a patient's blood
vessel, comprising the steps of: routing a catheter through a blood
vessel having a central axis, the catheter including an elongate
shaft having proximal and distal ends and defining a drive shaft
lumen, a driveshaft having proximal and distal ends disposed in the
drive shaft lumen, an ablation burr disposed on the distal end of
the driveshaft for rotation therewith, and first and second
inflation balloons disposed eccentrically on the shaft proximate
the burr, wherein inflation of the first balloon urges the ablation
burr in a first direction transverse of the central axis of the
blood vessel and inflation of the second balloon urges the ablation
burr in a second direction transverse of the central axis of the
blood vessel; inflating the first or second balloon to urge the
ablation burr in a direction transverse of the central axis of the
blood vessel and into contact with lesion material deposited on a
sidewall of the blood vessel; and rotating the burr.
33. The method of claim 32, further comprising: deflating the first
or second balloon; and inflating the other of the first or second
balloon to urge the ablation burr in another direction transverse
of the central axis of the blood vessel.
34. The method of claim 32, further comprising supporting a
proximal end of the ablation burr.
35. The method of claim 32, wherein the first and second balloons
are disposed on opposite sides of the shaft.
36. The method of claim 32, wherein the catheter further includes a
bearing positioned at the distal end of the shaft, the bearing
defining a bearing surface that is capable of supporting a proximal
end of the ablation burr.
37. The method of claim 36, wherein the bearing is cup shaped.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention generally relates to constructions for
intravascular treatment devices useful for removing vascular
occlusion material from a vascular occlusion or from a vascular
lumen. The invention more specifically relates to "expandable"
intravascular occlusion material removal devices, as well as to
methods of using those devices to treat vascular diseases. In this
context, "expandable" means that the burr can ablate a lumen having
a larger diameter than the diameter of the lumen of the guide
catheter to which the burr is advanced.
[0002] Vascular diseases, such as atherosclerosis and the like,
have become quite prevalent in the modern day. These diseases may
present themselves in a number of forms. Each form of vascular
disease may require a different method of treatment to reduce or
cure the harmful effects of the disease. Vascular diseases, for
example, may take the form of deposits or growths in a patient's
vasculature which may restrict, in the case of a partial occlusion,
or stop, in the case of a total occlusion, blood flow to a certain
portion of the patient's body. This can be particularly serious if,
for example, such an occlusion occurs in a portion of the
vasculature that supplies vital organs with blood or other
necessary fluids.
[0003] To treat these diseases, a number of different therapies are
being developed. While a number of invasive therapies are
available, it is desirable to develop non-invasive therapies as
well. Minimally invasive therapies may be less risky than invasive
ones, and may be more welcomed by the patient because of the
possibility of decreased chances of infection, reduced
post-operative pain, and less post-operative rehabilitation. One
type of non-invasive therapy for vascular diseases is
pharmaceutical in nature. Clot-busting drugs have been employed to
help break up blood clots which may be blocking a particular
vascular lumen. Other drug therapies are also available. Further,
minimally invasive intravascular treatments exist that are not only
pharmaceutical, but also revascularize blood vessels or lumens by
mechanical means. Two examples of such intravascular therapies are
balloon angioplasty and atherectomy which physically revascularize
a portion of a patient's vasculature.
[0004] Balloon angioplasty comprises a procedure wherein a balloon
catheter is inserted intravascularly into a patient through a
relatively small puncture, which may be located proximate the
groin, and intravascularly navigated by a treating physician to the
occluded vascular site. The balloon catheter includes a balloon or
dilating member which is placed adjacent the vascular occlusion and
then is inflated. Intravascular inflation of the dilating member by
sufficient pressures, on the order of 5 to 12 atmospheres or so,
causes the balloon to displace the occluding matter to
revascularize the occluded lumen and thereby restore substantially
normal blood flow through the revascularized portion of the
vasculature. It is to be noted, however, that this procedure does
not remove the occluding matter from the patient's vasculature, but
displaces it.
[0005] While balloon angioplasty is quite successful in
substantially revascularizing many vascular lumens by reforming the
occluding material, other occlusions may be difficult to treat with
angioplasty. Specifically, some intravascular occlusions may be
composed of an irregular, loose or heavily calcified material which
may extend relatively far along a vessel or may extend adjacent a
side branching vessel, and thus are not prone or susceptible to
angioplastic treatment. Even if angioplasty is successful, thereby
revascularizing the vessel and substantially restoring normal blood
flow therethrough, there is a chance that the occlusion may recur.
Recurrence of an occlusion may require repeated or alternative
treatments given at the same intravascular site.
[0006] Accordingly, attempts have been made to develop other
alternative mechanical methods of minimally invasive, intravascular
treatment in an effort to provide another way of revascularizing an
occluded vessel and of restoring blood flow through the relevant
vasculature. These alternative treatments may have particular
utility with certain vascular occlusions, or may provide added
benefits to a patient when combined with balloon angioplasty and/or
drug therapies.
[0007] One such alternative mechanical treatment method involves
removal, not displacement, as is the case with balloon angioplasty,
of the material occluding a vascular lumen. Such treatment devices,
sometimes referred to as atherectomy devices, use a variety of
means, such as lasers, and rotating cutters or ablaters, for
example, to remove the occluding material. The rotating cutters may
be particularly useful in removing certain vascular occlusions.
Since vascular occlusions may have different compositions and
morphology or shape, a given removal or cutting element may not be
suitable for removal of a certain occlusion.
[0008] Alternatively, if a patient has multiple occlusions in his
vasculature, a given removal element may be suitable for removing
only one of the occlusions. Suitability of a particular cutting
element may be determined by, for example, its size or shape. Thus,
a treating physician may have to use a plurality of different
treatment devices to provide the patient with complete treatment.
This type of procedure can be quite expensive because multiple
pieces of equipment may need to be used (such intravascular devices
are not reusable because they are inserted directly into the blood
stream), and may be tedious to perform because multiple pieces of
equipment must be navigated through an often-tortuous vascular path
to the treatment site.
SUMMARY OF THE INVENTION
[0009] The present invention pertains generally to devices for
performing atherectomy. In particular, various embodiments of an
atherectomy device are disclosed which can ablate a lumen having a
larger diameter than the diameter of the lumen of the guide
catheter through which the device is advanced.
[0010] In one embodiment, an elongate shaft is provided having a
proximal and a distal end. The shaft defines a lumen. A burr
deflector is disposed at the distal end of the shaft. The burr
deflector includes a burr engaging surface. An elongate rotatable
drive shaft extends through the lumen of the first shaft. The drive
shaft has a proximal end and a distal end. A burr is disposed at
the distal end of the drive shaft. The drive shaft and burr are
shiftable relative to the burr deflector. The drive shaft and burr
may be shifted between a first position and a second position,
wherein the burr is transversely shifted relative to the burr
deflector. Preferably, the deflection is co-linear to the length of
the drive shaft.
[0011] The burr engaging surface is preferably disposed at an acute
angle to the length of the first shaft. The burr preferably
includes an engaging surface disposed at an acute angle relative to
the drive shaft such that the engaging surfaces provide a path
along which the burr can shift transversely relative to the burr
deflector.
[0012] In yet another embodiment of a device in accordance with the
present invention an elongate shaft is provided which has a
proximal and a distal end. The shaft defines a lumen. An elongate
rotatable drive shaft extends through the lumen. The drive shaft
has a proximal end and a distal end. A burr is disposed at the
distal end of the drive shaft. A bushing is disposed around the
drive shaft proximate the burr. A steering line is connected to the
bushing. The steering line can be pulled by an operator to shift
the bushing and thus the burr and drive transversely.
[0013] In yet another embodiment of a device in accordance with the
present invention, an elongate rotatable drive shaft is provided
having a proximal and a distal end. An ablation burr is disposed at
the distal end of the drive shaft. The ablation burr includes a
mechanism which expands transversely in response to the centrifugal
force generated when the burr rotates.
[0014] In one embodiment, the mechanism is generally tubular and
has a proximal end and a distal end constrained against expansion.
The central portion of the tubular member is allowed to expand
under the influence of the centrifugal force. In yet another
embodiment of the mechanism, a member having a generally helical
cross-section is provided which tends to unwind, increasing its
transverse diameter as the burr rotates. In yet another embodiment
of the mechanism, a line is provided having a proximal end and a
distal end. The ends of the line are held a distance apart less
than the length of the line. An abrasive is disposed on the line.
As the burr is rotated, the line moves transversely. In yet another
embodiment of the mechanism includes a plurality of bristles which
can shift transversely under the influence of centrifugal
force.
[0015] In another embodiment of the atherectomy device in
accordance with the present invention, an elongate rotatable drive
shaft is provided having a proximal end and a distal end. A lumen
is defined through the elongate drive shaft. A balloon including an
outer surface and defining a balloon enclosure in fluid
communication with the inflation lumen is disposed at the distal
end of the drive shaft. An abrasive is disposed on the outer
surface of the balloon. The balloon can be dilated by pressure or
centrifugal force to increase the transverse dimension of the
abrasive surface.
[0016] In yet another embodiment of an atherectomy device in
accordance with the present invention, an elongate shaft is
provided having a proximal end and a distal end. The shaft defines
a drive shaft lumen and an inflation lumen. A rotatable drive
shaft, having a proximal end and a distal end, is disposed in the
drive shaft lumen. An ablating burr is disposed at the distal end
of the drive shaft. A balloon is disposed eccentrically on the
drive shaft proximate the burr. The balloon can be inflated to push
against the vessel wall and shift the drive shaft and burr
transversely within the vessel lumen.
[0017] In yet another embodiment of an atherectomy device in
accordance with the present invention, an elongate rotatable drive
shaft is provided having a proximal end and a distal end. An
ablation burr is eccentrically connected to the drive shaft at the
distal end of the shaft. A counterweight is disposed on the burr to
place the center of mass of the burr in line with the longitudinal
axis of the drive shaft. The presence of the counterweight dampens
whipping of the burr which might otherwise occur during rotation of
the drive shaft. This embodiment is related to that disclosed in
U.S. patent application Ser. No. 08/987,969, filed Dec. 10, 1997
and entitled ASYMMETRIC BURRS FOR ROTATIONAL ABLATION incorporated
herein by reference.
[0018] In yet another embodiment of the atherectomy device in
accordance with the present invention, an elongate shaft is
provided having a proximal end and a distal end. The shaft defines
a lumen therethrough. A rotatable drive shaft having a proximal end
and a distal end, is disposed through the lumen. A burr, including
a plurality of spring members is disposed at the distal end of the
drive. The drive shaft and the burr are shiftable between a first
position and a second position. In the first position, the spring
members are disposed at least in part within the lumen of the first
shaft and are transversely constrained thereby. In the second
position, the spring members are transversely restrained less than
in the first position such that the burr has a greater transverse
dimension in the second position than in the first position.
[0019] In yet another embodiment of an atherectomy device in
accordance with the present invention, an elongate rotatable drive
shaft is provided having a proximal end and a distal end, the drive
shaft includes a generally helical-shaped portion proximate the
distal end biased to expand when unconstrained. An abrasive is
disposed on the helical portion. The helical portion can be
advanced to the site where atherectomy will be performed in a
constrained and collapsed state through a guide catheter. When the
helical shaped portion exits the guide catheter, the helically
shaped portion, then unconstrained, will expand transversely.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 is a side view of a catheter assembly in accordance
with the present invention;
[0021] FIG. 2 is a side view of another embodiment of a catheter in
accordance with the present invention;
[0022] FIG. 3 is a side view of yet another embodiment of the
catheter in accordance with the present invention;
[0023] FIG. 4 is a longitudinal, cross-sectional view of yet
another embodiment of the catheter in accordance with the present
invention;
[0024] FIG. 5 is a fragmentary, cross-sectional view of yet another
catheter in accordance with the present invention;
[0025] FIG. 6 is a side view of yet another embodiment of the
catheter in accordance with the present invention;
[0026] FIG. 7 is a side view of yet another embodiment of the
catheter in accordance with the present invention;
[0027] FIG. 8 is a side view of yet another embodiment of the
catheter in accordance with the present invention;
[0028] FIG. 9 is a perspective view of yet another embodiment of
the catheter in accordance with the present invention;
[0029] FIG. 10 is a perspective view of yet another embodiment of
the catheter in accordance with the present invention;
[0030] FIG. 11 is a side view of yet another embodiment of the
catheter in accordance with the present invention;
[0031] FIG. 12 is a side view of yet another embodiment of the
catheter in accordance with the present invention;
[0032] FIG. 13 is a view of the embodiment of FIG. 12 in use;
[0033] FIG. 14 is a side view of yet another embodiment of the
catheter in accordance with the present invention;
[0034] FIG. 15 is a side view of yet another embodiment of the
catheter in accordance with the present invention;
[0035] FIG. 16 is a distal end view of the catheter of FIG. 15;
[0036] FIG. 17 is a cross-sectional view of the catheter of FIG.
15;
[0037] FIG. 18 is a side view of yet another embodiment of the
catheter in accordance with the present invention; and
[0038] FIG. 19 is a cross-sectional view of yet another embodiment
of the catheter in accordance with the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0039] Referring now to the drawings, wherein like reference
numerals refer to like reference elements throughout the several
views, FIGS. 1 is a side view of catheter 10 in accordance with the
present invention. As shown in FIG. 1, catheter 10 is disposed
within vessel 12 proximate a plaque deposit 14. Catheter 10
includes an elongate shaft 16. Shaft 16 includes an outer shaft 18
having a proximal end a distal end and defining a drive shaft lumen
therethrough. Catheter 16 also includes a drive shaft 20 having a
proximal end a distal end and extending through outer shaft 18.
Disposed at the distal end of outer shaft 18 is a burr deflector 22
having a burr engaging surface 24. Disposed at the distal end of
drive shaft 20 is a burr 26 rotatable by drive shaft 20, and
including an abrasive surface 28.
[0040] As will be appreciated by those skilled in the art, suitable
manifold and motor can be provided at the proximal end of catheter
10 to rotate burr 26 and facilitate the uses of catheter 10 as
herein described. Those skilled in the art will appreciate the
various biocompatible materials available to construct catheter 10
including burr 26. This is also true with respect to the various
embodiments of the catheters discussed below. Those skilled in the
art will recognize the various manifold, motor, infusion displays
control mechanisms and other devices that can advantageously be
connected to the proximal ends of the catheter to facilitate their
use. Additionally, those skilled in the art will recognize various
biocompatible materials, and methods available to construct each
embodiment.
[0041] In use, catheter 10 is advanced percutaneously to a coronary
lesion including plaque 14. Burr 26 is advanced to plaque as shown
by the arrow parallel to shaft 16. Burr 26 is then rotated by drive
shaft 26 as shown by the arrows such that plaque deposit 14 is
grounded to micro fine particles. Catheter 10 can be advanced to
the lesion through a guide catheter (not shown) having an inner
lumen at least slightly greater in diameter than the diameter of
burr 26.
[0042] As shown in FIG. 1, the inside diameter of vessel 12 is
greater than the diameter of burr 26. In order for burr 26 to be
positioned within vessel 12, to remove plaque 14, shaft 10 can be
drawn proximally to engage burr 26 against burr deflector surface
24. As burr 26 is forced into surface 24 it will tend to slide
proximally along surface 24 while simultaneously being displaced
transversely as shown by the arrow on burr 26. The greater the
transverse dimension of surface 24, the greater is the possible
transverse movement of burr 26. The transverse movement of burr 26
is preferably co-linear with the length of the drive shaft.
[0043] FIG. 2 is a view of an alternate embodiment of an
atherectomy catheter 50 in accordance with the present invention.
Catheter 50 includes an elongate shaft 56 including an outer shaft
58 defining a drive shaft lumen therethrough. A drive shaft 60
extends through the lumen. Drive shaft 60 includes a proximal end
and a distal end. Disposed at the distal end of drive shaft 60 is a
burr 66 having an abrasive coating 68. Disposed around a proximal
portion of burr 66 is a bushing 70. Bushing 70 can include an
inwardly disposed circumferential flange which engages a
circumferential groove (not shown) in burr 66 such that bushing 70
is fixedly connected to burr 66, yet burr 66 can rotate within
bushing 70. Connected to opposite sides of bushing 70 and extending
proximally through shaft 58 are steering wires 72 and 74.
[0044] Catheter 50 can be used as described above with respect to
catheter 10. Unlike catheter 10, however, rather than having a burr
deflector 22 to transversely move burr 26, burr 60 can be shifted
from side to side by pulling proximally a steering wire 72 or 74.
Pulling steering wire 74 proximally as steering wire 72 is allowed
to move distally will shift burr 66 transversely toward wire 74 as
shown by the arrow on burr 66. Similarly, burr 66 can be shifted
transversely in the opposite direction by pulling steering wire 72
proximally while allowing wires 74 to shift distally.
[0045] To perform an atherectomy procedure using catheter 50,
catheter 50 can be advanced to percutaneously to the cite of the
lesion through a guide catheter having an inside diameter at least
slightly greater than the transverse diameter of burr 66. Burr 66
can be rotated as shown by the arrow proximate drive shaft 60 and
be engaged with the lesion. Burr 66 can be moved transversely by
steering wires 72 and 74 as necessary to remove the plaque.
[0046] FIG. 3 is a view of yet another embodiment of an atherectomy
catheter 110 in accordance with the present invention. Catheter 110
includes an elongate drive shaft 120 having a proximal end and
distal end. Drive shaft 120 defines a lumen 121 therethrough.
Disposed at the distal end of drive shaft 120 is burr 126 having an
abrasive coating 128. Burr 126 includes a generally tubularly
shaped member 130 connected to burr 126 at the member's proximal
and distal ends. Burr 126 includes lumens 132 in fluid
communication with lumen 121 of shaft 120. Lumens 132 lead from
lumen 121 to the inside surface of member 130.
[0047] In use, catheter 110 is advanced to a lesion as described
above with respect to the other catheter embodiments. Rather than
including a mechanism for transversely shifting a burr however, the
tubular member 130 of burr 126 is sufficiently elastic to stretch
transversely under the influence of centrifugal force when tip 126
is rotated by shaft 120. Rotation of tip 126, thus will move
tubular member 130 from a first position A to a second position B.
In second position B, burr 126 can ablate a larger diameter path.
While member 130 is moving from position A to position B, fluid may
be introduced through lumens 121 and 132 as shown by the arrows
into the space created inside member 130.
[0048] FIG. 4 is a cross-sectional view of yet another embodiment
of a catheter 150 in accordance with the present invention.
Catheter 150 includes an elongate shaft 156 defining an inflation
lumen 157. Disposed proximate the proximal end of shaft 156 is a
balloon 166 defining a burr having an abrasive coating 168.
Catheter 150 can include a manifold 176 including lumens 178 in
fluid communication with lumen 157 and the interior space of
balloon 166.
[0049] In use, balloon 166 is advanced percutaneously to a lesion.
At the lesion, balloon 166 is inflated to increase its diameter.
Abrasive surface 168 is then advanced into engagement with the
plaque. Balloon 166 is then rotated to abrade plaque.
[0050] FIG. 5 is a partial, cross-sectional view of yet another
embodiment of a catheter 210 in accordance with the present
invention. Catheter 210 includes an elongate drive shaft 220 having
a proximal end and a distal end. A burr 226 is disposed at the
distal end of drive shaft 220. Burr 226 includes an abrasive
coating 228 and a distal flexible portion or skirt 229 which is
free to move generally transversely under the influence of
centrifugal force as burr 226 is rotated by shaft 220. The arrows
proximate skirt 229 show that the direction of the generally
transverse movement of skirt 229 to increase the effective diameter
of burr 226. The arrow proximate the distal end of burr 226 shows
the rotation of burr 226. While burr 226 is not rotating skirt 229
can be disposed generally parallel to shaft 220 and then
elastically stretch to the position shown in FIG. 5 when burr 226
is rotated.
[0051] FIG. 6 is a side view of yet another alternate embodiment of
a catheter 250 in accordance with the present invention. Catheter
250 is shown disposed within a vessel lumen 252. Catheter 250
includes an elongate shaft 256 having a proximal end and a distal
end. Catheter 256 includes an outer shaft 258 which defines the
drive shaft lumen and two inflation lumens 261. An elongate drive
shaft 260 is disposed through the drive shaft lumen. A cup shaped
bearing 265 is disposed at the distal end of shaft 256. A burr 266
is connected to the distal end of drive shaft 260. The distal end
of burr 266 can include an abrasive coating 268. The proximal end
of burr 266 can be nested within bearing 265. Connected to shaft
258 proximate burr 266 are balloons 263. Balloons 263 define a
balloon envelope in fluid communication with inflation lumens 261.
Additional balloons may be used to increase the positional control
of burr 266.
[0052] Catheter 250 is advanced as described above with respect to
the alternate embodiments in accordance with the present invention
to perform the atherectomy procedure. Likewise, burr 266 is rotated
to abrade plaque. In order to shift burr 266 transversely within
lumen 252, balloons 263 may be alternately inflated or deflated to
engage the wall of vessel 252 forcing burr 266 transversely in a
direction opposite the resultant force of balloons 263 incident the
wall of vessel 252.
[0053] FIG. 7 is a side view of yet another embodiment of a
catheter 310 in accordance with the present invention. Catheter 310
includes an elongate shaft 320. Shaft 320 includes a proximal end
and a distal end. A burr 326 is disposed eccentrically on shaft 320
proximate the distal end of shaft 320. Burr 326 includes an
abrasive coating 328. A counterweight 327 is disposed in burr 326.
The counterweight has a weight sufficient to shift the center of
mass of burr 326 such that it lies generally on the longitudinal
axis of shaft 320. The effect of counterweighting can also be
achieved by an asymmetrical shaping of the burr and/or creating
voids in the burr to shift the distribution of the burrs weight.
This allows burr 326 to be rotated by shaft 320 through a position
A and B as shown without whipping the distal end of shaft 322. By
eccentrically mounting burr 326 on shaft 320 it can be appreciated
by reference to positions A and B that a larger area can be
circumscribed by the surface of burr 326 as burr 326 is rotated by
shaft 320 than if the burr were rotated about its central axis.
[0054] FIG. 8 is a view of yet another embodiment of a catheter 350
in accordance with the present invention. Catheter 350 includes an
elongate shaft 356. Shaft 356 includes an outer shaft 358 having a
proximal end and a distal end and defining a drive shaft lumen
therethrough. Shaft 356 also includes a drive shaft 360 disposed
through the drive shaft lumen. A cone-shaped bearing 365 is
preferably disposed at the distal end of shaft 358. Bearing 356 has
a lumen extending longitudinally therethrough, and having a
diameter which generally increases distally. A burr 366 is disposed
at the distal end of drive shaft 360. Burr 366 can have an abrasive
coating (not shown). Burr 366 is preferably formed from a plurality
of spring members 380 joined at their respective proximal and
distal ends. Members 380 are preferably preformed to assume a
transversely expanded shape when unconstrained. The diameter of
burr 366 can be reduced by withdrawing burr 366 at least in part
into bearing 365. Burr 366 may be withdrawn at least partially into
bearing 365 by shifting drive shaft 360 proximally relative to
outer shaft 358. Burr 366 can be advanced to the cite of a lesion
in the constrained configuration and then expanded, and rotated to
abrade plaque.
[0055] FIG. 9 is an embodiment of yet another catheter 410 in
accordance with the present invention. Catheter 410 includes a
drive shaft 420 having a proximal end and a distal end. A generally
spiral shaped ablation burr 434 is disposed at the distal end of
drive shaft 420. Burr 434 can include an abrasive coating (not
shown). Upon rotation of drive shaft 420, burr 434 can generally
expand or unwind from a position A to a position B under the
influence of centrifugal force. Burr 434 as shown has a generally
circular cross section. Burr 434 can have a generally rectangular
cross section if burr 434 were formed from a ribbon shaped
member.
[0056] FIG. 10 is a view of yet another embodiment of a catheter
450 in accordance with the present invention. Catheter 450 includes
an elongate drive shaft 460 having a proximal end and a distal end.
A burr 466 is disposed proximate the distal end of shaft 460. Burr
466 can include an abrasive coating 468. A coil 482 can be formed
in drive shaft 460 proximate burr 466. Abrasive coating 484 can be
deposited on coil 482. Abrasive coating 484 can be deposited in the
configuration and plurality of burrs. Coil 482 can be stretched and
flattened to be advanced through a guide catheter. As the coil
portion of drive shaft 460 is advanced distally from a guide
catheter, that portion of drive shaft 460 resumes the coil shape
shown in FIG. 10.
[0057] FIG. 11 is a view of yet another catheter 510 in accordance
with the present invention. Catheter 510 includes drive shaft 520
having a proximal end and a distal end. A burr 526 is disposed at
the distal end of drive shaft 520. Burr 526 preferably includes an
abrasive coating 528. Burr 526 is preferably formed from a
generally tubular member 541 which is sealed at its distal end to
form an abrasive tip 543. Longitudinal slits 540 are formed in the
proximal end of tubular member 541 such that leaves 542 are
disposed therebetween. When burr 526 is rotated, leaves 542 will
move from a first position A to a second position B under the
influence of centrifugal force.
[0058] FIG. 12 is a view of yet another embodiment of a catheter
550 in accordance with the present invention. Catheter 550 includes
an elongate drive shaft 560 having a proximal end and a distal end.
Proximate the distal end of drive shaft 560 is a line 586 having a
proximal end and a distal end. The proximal end and distal ends of
line 586 are connected to drive shaft 560 at a spaced distance less
than the length of line 586. Abrasive burrs 588 are deposited along
line 586. In FIG. 12, line 586 is in a first position A. In FIG.
13, line 586 is shown in a second position B wherein line 586 is
shift transversely under the influence of centrifugal force as
drive shaft 560 is rotated.
[0059] FIG. 14 is a view of yet another catheter 610 in accordance
with the present invention. Catheter 610 includes a drive shaft 620
having a proximal end and a distal end. A burr 626 is disposed
proximate the distal end of shaft 620. Burr 626 preferably includes
an abrasive coating 628. A plurality of bristles extend from burr
626. Disposed at the outside end of each bristle 636 is a burr end
638 which may include an abrasive coating. Bristles 636 can be
configured to move from first position A to second position B under
the influence of centrifugal force as burr 626 is rotated.
Alternately, bristles 633 may be biased to expand between positions
A and B upon becoming unconstrained as they are advanced from a
guide catheter.
[0060] FIG. 15 is a side view of yet another catheter 650 in
accordance with the present invention. Catheter 650 includes an
elongate drive shaft 656 which can include a proximal, helical
shaft encased in a polymer. Shaft 656 can also include a distal
shaft portion 659 around which is disposed an elastomeric balloon
667. Elastomeric balloon 667 includes a distal portion which is
folded over into folds or leaflets 669. The distal end of catheter
650 including the folded region of balloon 667 is preferably coated
with an abrasive. FIG. 16 is a view of the distal end of catheter
650 of FIG. 15 and offers an alternate view of folds 669.
[0061] FIG. 17 is a cross-sectional view of catheter 650 of FIG.
15. The arrow to the right of the figure shows the direction of
rotation of balloon 667. In use, as can be seen by comparison of
FIG. 17 with FIG. 15, during rotation of balloon 667, the balloon's
distal portion including leaves 669 expands from a first position A
to a second position B. This is made possible as the space defined
between the balloon inner surface and shaft 659 is preferably
preloaded with a fluid such as saline prior to advancement to the
site of the lesion. The quantity of fluid preloaded into balloon
667 is such that when balloon 667 is not rotated, it will be in a
relatively reduced diameter, i.e., position A. Whereas, when
balloon 667 is rotated, the fluid with shift by centrifugal force
into that distal portion of balloon 667 including leaves 669,
expanding balloon 667 into the increased diameter configuration of
position B.
[0062] FIG. 18 shows yet another alternate embodiment of a catheter
710 in accordance with the present invention. Catheter 710 has an
elongate shaft 716 having a proximal end a distal end. Shaft 716
includes an outer sheath 718 defining a drive shaft lumen
therethrough. Shaft 716 includes an elongate drive shaft 720
disposed through the lumen. Sheath 718 includes a distal bearing
surface which preferably defines a lumen having an inside diameter
increasing distally. Disposed at the distal end of drive shaft 720
is an expandable burr 726 which preferably has an abrasive coating
(not shown). Burr 726 can be formed from a plurality of spring
member similar to the spring members 380 of catheter 350 shown in
FIG. 8. For clarity, in FIG. 18, only two spring members 740 are
shown.
[0063] An elastomeric shell is disposed within burr 726 to avoid an
increase in hemolysis or platelet aggregation. Shell 742 preferably
encloses a main body 743 and unidirectional ratchet 744 including
reverse positive stop 746. A threaded member 800 is threaded into a
sleeve 745. Threaded member 800 is fixably connected at its distal
end to stop 746 and fixably connected at its proximal end to
forward motion positive stop 747. Threaded member 800 is also
fixably connected to drive shaft 720. Spring members 740 are
connected at their proximal ends to sleeve 745 and fixably held in
position by collar 748. The distal ends of spring members 740 are
fixably connected to the distal end of main body 743. Main body 743
is connected at its proximal end about a pin 804 to ratchet 744.
Ratchet 744 includes teeth 802 and the main body portion includes
teeth 806. Teeth 802 and 806 are shown in FIG. 8 meshed along
angled surfaces 808 and longitudinally extended surfaces 810.
[0064] In use, ratchet 744 and main body 743 can be used to control
the transverse diameter D of burr 726. For example, a burr
advancable through an 8F guide catheter could be expanded between
2.0 mm and 3.5 mm in diameter, at 0.25 mm intervals or steps. The
ability to control the diameter of burrs 726 at such steps can be
considered indexing. To increase the diameter of burr 726 by
indexing, drive shaft 720 can be rotated such that teeth 802 and
806 engage each other along surfaces 808. Since surfaces 808 are
inclined, teeth 806 will tend to rise out from between 802
momentarily increasing the length of burr 726. As drive shaft 720
continues to rotate, the teeth will index and reengage the adjacent
teeth. As ratchet 744 was rotated, stop 746 will have moved toward
stay 745 shortening the distance between distal end 749 of burr 726
and sleeve 745, thus increasing the diameter of burr 726. This
assumes that the spring members 740 bias burr 726 toward its
largest diameter. This procedure can be repeated to step wise
increase the diameter of burr 726. It can be appreciated that burr
726 can be kept from rotating during indexing by engagement with
sheath 718 or the vessel or vessel lesion. When drive shaft 720 is
rotating in the opposite direction to engage teeth 802 and 806
along longitudinally extending surface 810, burr 726 can be rotated
to ablate a lesion.
[0065] The diameter of burr 726 can be reduced by merely
withdrawing it at least in part into sheath 718. Burr 726 can be
withdrawn into sheath 718 sufficiently such that teeth 802 and 806
will be unmeshed. When teeth 802 and 806 are unmeshed, drive shaft
720 can be rotated to advance stop 747 to sleeve 745. At that
point, burr 726 is reset to index from its smallest indexing
diameter to its largest as described above.
[0066] FIG. 19 is a cross-sectional view of yet another embodiment
of a catheter 750 in accordance with the present invention.
Catheter 750 includes an elongate drive shaft 760 having a proximal
end and a distal end. Drive shaft 760 can be, for example, formed
from a helical member surrounded by a polymer sheath. A burr 766 is
disposed at the distal end of shaft 760 connected to burr 766 is a
loosely spiraled ribbon member 767 which has a reduced length and
width as it spirals outwardly from shaft 760. Abrasive coating 768
can also be applied to ribbon member 767. Like the spiraling member
434 of catheter 410 of FIG. 9, ribbon member 767 will tend to
unwind and expand transversely when rotated in one direction.
[0067] Numerous advantages of the invention covered by this
document have been set forth in the foregoing description. It will
be understood, however, that this disclosure is, in many respects,
only illustrative. Changes may be made in details, particularly in
matters of shape, size, and arrangement of parts without exceeding
the scope of the invention. The inventions's scope is, of course,
defined in the language in which the appended claims are
expressed.
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