U.S. patent application number 16/196894 was filed with the patent office on 2019-12-19 for atherectomy devices and methods.
The applicant listed for this patent is Cardio Flow, Inc.. Invention is credited to Albert Selden Benjamin, Michael Kallok, Charles Anthony Plowe, Paul Joseph Robinson, Cassandra Ann Piippo Svendsen.
Application Number | 20190380737 16/196894 |
Document ID | / |
Family ID | 68838961 |
Filed Date | 2019-12-19 |
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United States Patent
Application |
20190380737 |
Kind Code |
A1 |
Kallok; Michael ; et
al. |
December 19, 2019 |
ATHERECTOMY DEVICES AND METHODS
Abstract
Rotational atherectomy devices and systems can remove or reduce
stenotic lesions in implanted grafts by rotating one or more
abrasive elements within the graft. The abrasive elements can be
attached to a distal portion of an elongate flexible drive shaft
that extends from a handle assembly that includes a driver for
rotating the drive shaft. In particular implementations, individual
abrasive elements are attached to the drive shaft at differing
radial angles in comparison to each other (e.g., configured in a
helical array). The centers of mass of the abrasive elements can
define a path that fully or partially spirals around the drive
shaft.
Inventors: |
Kallok; Michael; (St. Paul,
MN) ; Svendsen; Cassandra Ann Piippo; (Blaine,
MN) ; Robinson; Paul Joseph; (Mahtomedi, MN) ;
Plowe; Charles Anthony; (Blaine, MN) ; Benjamin;
Albert Selden; (St. Paul, MN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Cardio Flow, Inc. |
St. Paul |
MN |
US |
|
|
Family ID: |
68838961 |
Appl. No.: |
16/196894 |
Filed: |
November 20, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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16008136 |
Jun 14, 2018 |
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16196894 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B 2017/320766
20130101; A61B 17/320758 20130101; A61B 2017/320716 20130101; A61B
17/320725 20130101; A61B 2017/320733 20130101; A61B 2017/320004
20130101; A61B 2017/22069 20130101; A61B 2017/320008 20130101 |
International
Class: |
A61B 17/3207 20060101
A61B017/3207 |
Claims
1. A method for performing rotational atherectomy to remove
stenotic lesion material from an arteriovenous graft of a patient,
the method comprising: delivering a portion of a rotational
atherectomy system into the arteriovenous graft, wherein the
rotational atherectomy system comprises: an rotational atherectomy
device comprising: an elongate flexible drive shaft comprising a
torque-transmitting coil and defining a longitudinal axis, the
drive shaft being configured to rotate about the longitudinal axis;
and a helical array of abrasive elements attached to a distal end
portion of the drive shaft, each of the abrasive elements having a
center of mass that is offset from the longitudinal axis, the
centers of mass of each of the abrasive elements arranged along a
spiral path around the longitudinal axis; and a controller;
rotating the drive shaft about the longitudinal axis such that the
helical array of abrasive elements orbit around the longitudinal
axis; and selecting an input on a user interface of the controller
that corresponds to a specific graft size.
2. The method of claim 1, wherein the delivering comprises
translationally moving the drive shaft along the longitudinal
axis.
3. The method of claim 1, further comprising modifying a speed of
the drive shaft during the rotating.
4. The method of claim 3, wherein modifying the speed of the drive
shaft modifies a diameter of rotation.
5. The method of claim 1, wherein delivering the rotational
atherectomy device comprises delivering the rotational atherectomy
device with a distal portion of the rotational atherectomy device
positioned toward a vein of the patient.
6. The method of claim 1, wherein delivering the rotational
atherectomy device comprises delivering the rotational atherectomy
device with a distal portion of the rotational atherectomy device
positioned toward an artery of the patient to treat a lesion at an
arterial anastomosis.
7. The method of claim 1, further comprising means for compressing
a lesion against an inner wall of the arteriovenous graft.
8. The method of claim 1, further comprising a distal stability
element affixed to the drive shaft and having a center of mass
aligned with the longitudinal axis, the distal stability element
distally spaced apart from the helical array of abrasive
elements.
9. The method of claim 1, wherein the system includes means for
stabilizing the drive shaft.
10. The method of claim 1, wherein the system includes means for
extending a distal portion of the device.
11. The method of claim 1, wherein the system further comprises an
actuator handle assembly that includes a housing and a carriage
assembly.
12. The method of claim 11, further comprising slidably translating
the carriage assembly along the longitudinal axis of the handle
assembly.
13. The method of claim 11, further comprising controlling the
rotational atherectomy procedure using an electric handle coupled
to the carriage assembly.
14. The method of claim 11, further comprising driving rotations of
the drive shaft using an electric motor, wherein the electric motor
is coupled to the carriage assembly.
15. The method of claim 14, further comprising actuating an
electrical switch of the carriage assembly to drive the electric
motor.
16. The method of claim 1, further comprising positioning the
helical array of abrasive elements in a targeted position within
the arteriovenous graft.
17. (canceled)
18. A method for performing rotational atherectomy to remove
stenotic lesion material from an arteriovenous graft of a patient,
the method comprising: delivering a portion of a rotational
atherectomy system into the arteriovenous graft, wherein the
rotational atherectomy system comprises: an rotational atherectomy
device comprising: an elongate flexible drive shaft comprising a
torque-transmitting coil and defining a longitudinal axis, the
drive shaft being configured to rotate about the longitudinal axis;
and a helical array of abrasive elements attached to a distal end
portion of the drive shaft, each of the abrasive elements having a
center of mass that is offset from the longitudinal axis, the
centers of mass of each of the abrasive elements arranged along a
spiral path around the longitudinal axis; and a controller; and
rotating the drive shaft about the longitudinal axis such that the
helical array of abrasive elements orbit around the longitudinal
axis, wherein the controller determines the appropriate RPM for
rotating the helical array of abrasive elements in the
arteriovenous graft based on its diameter.
19. The method of claim 1, wherein the delivering comprises
delivering the rotational atherectomy device to the arteriovenous
graft located in a leg of a patient.
20. The method of claim 1, wherein said helical array of abrasive
elements attached to the distal end portion of the drive shaft
comprises a proximal-most eccentric abrasive element, a distal-most
eccentric abrasive element, and at least one intermediate eccentric
abrasive element positioned between the proximal-most eccentric
abrasive element and the distal-most eccentric abrasive element,
wherein both the proximal-most eccentric abrasive element and the
distal-most eccentric abrasive element are smaller in maximum outer
diameter than said at least one intermediate eccentric abrasive
element.
21. The method of claim 18, further comprising selecting an input
on a user interface of the controller that corresponds to a
specific graft size.
22. The method of claim 18, further comprising modifying a speed of
the drive shaft during the rotating.
23. The method of claim 18, further comprising a distal stability
element affixed to the drive shaft and having a center of mass
aligned with the longitudinal axis, the distal stability element
distally spaced apart from the helical array of abrasive
elements.
24. The method of claim 18, wherein the system further comprises an
actuator handle assembly that includes a housing and a carriage
assembly.
25. The method of claim 18, wherein said helical array of abrasive
elements attached to the distal end portion of the drive shaft
comprises a proximal-most eccentric abrasive element, a distal-most
eccentric abrasive element, and at least one intermediate eccentric
abrasive element positioned between the proximal-most eccentric
abrasive element and the distal-most eccentric abrasive element,
wherein both the proximal-most eccentric abrasive element and the
distal-most eccentric abrasive element are smaller in maximum outer
diameter than said at least one intermediate eccentric abrasive
element.
Description
CLAIM OF PRIORITY
[0001] This application is a continuation of U.S. patent
application Ser. No. 16/008,136, filed on Jun. 14, 2018, the entire
contents of which are hereby incorporated by reference.
TECHNICAL FIELD
[0002] This document relates to rotational atherectomy devices and
systems for removing or reducing stenotic lesions in blood vessels
and/or arteriovenous grafts, for example, by rotating an abrasive
element within the vessel to partially or completely remove the
stenotic lesion material.
BACKGROUND
[0003] Blood flow through the peripheral arteries (e.g., iliac,
femoral, renal etc.), can be affected by the development of
atherosclerotic blockages. Peripheral artery disease (PAD) can be
serious because without adequate blood flow, the kidneys, legs,
arms, and feet may suffer irreversible damage. Left untreated, the
tissue can die or harbor infection. Patients that have kidneys that
do not function properly may require hemodialysis to purify the
blood of the patient. To gain access to the blood for hemodialysis,
an arteriovenous fistula or a graft can be used to connect an
artery and a vein. Similar to blood vessels, fistulas and/or grafts
can become clogged with plaque.
SUMMARY
[0004] This document relates to rotational atherectomy devices,
systems, and methods for removing or reducing stenotic lesions in
an implanted graft (e.g., a synthetic arteriovenous (AV) graft) by
rotating one or more abrasive elements to abrade and breakdown the
lesion. Vascular access stenosis is a common issue found in
hemodialysis patients. In various embodiments, a graft can be
implanted into a hemodialysis patient to access blood vessels
capable of providing rapid extracorporeal blood flow during
hemodialysis. The implanted graft may be prone to vascular access
stenosis, which forms fibrous plaque-like lesions within the lumen
of the graft and extending into the native artery and vein attached
to the graft. Stenotic lesions that typically develop in
association with the implanted graft can contain non-calcified
neointimal hyperplasia and may lead to thrombosis and graft
occlusion.
[0005] Some embodiments of the systems and devices provided herein
can abrade stenotic lesions in the grafts by rotating the abrasive
element(s) according to a stable and predictable orbiting profile.
In some embodiments, the abrasive element(s) are attached to a
distal portion of an elongate flexible drive shaft that extends
from a handle assembly. In particular embodiments, a rotational
atherectomy device comprises an elongate flexible drive shaft with
multiple eccentric abrasive elements that are attached to the drive
shaft, and one or more stability elements are attached to the drive
shaft such that at least one stability element is distal of the
abrasive element. Optionally, the stability elements have a center
of mass that are axially aligned with a central longitudinal axis
of the drive shaft while the eccentric abrasive element(s)
has(have) a center(s) of mass that is(are) axially offset from
central longitudinal axis of the drive shaft.
[0006] In some embodiments, multiple abrasive elements are coupled
to the drive shaft and are offset from each other around the drive
shaft such that the centers of the abrasive elements are disposed
at differing radial angles from the drive shaft in relation to each
other. For example, in some embodiments a path defined by the
centers of mass of the abrasive elements defines a spiral around a
length of the central longitudinal axis of the drive shaft. A
flexible polymer coating may surround at least a portion of the
drive shaft, including the stability element(s) in some
embodiments. Also, in some optional embodiments, a distal extension
portion of the drive shaft may extend distally beyond the
distal-most stability element.
[0007] In one aspect, this disclosure is directed to a method for
performing rotational atherectomy to remove stenotic lesion
material from an arteriovenous graft of a patient. The method
includes delivering a rotational atherectomy device into the
arteriovenous graft. The rotational atherectomy device includes an
elongate flexible drive shaft that includes a torque-transmitting
coil and defines a longitudinal axis, the drive shaft being
configured to rotate about the longitudinal axis, and a helical
array of abrasive elements attached to a distal end portion of the
drive shaft, each of the abrasive elements having a center of mass
that is offset from the longitudinal axis, the centers of mass of
the abrasive elements arranged along a path that spirals around the
longitudinal axis. The method further includes rotating the drive
shaft about the longitudinal axis such that the abrasive elements
orbit around the longitudinal axis.
[0008] In another aspect, this disclosure is directed to a method
for performing rotational atherectomy to remove stenotic lesion
material from an arteriovenous graft of a patient. The method can
include delivering a rotational atherectomy device into the
arteriovenous graft. The rotational atherectomy device can include
an elongate flexible drive shaft that includes a
torque-transmitting coil and defines a longitudinal axis, the drive
shaft being configured to rotate about the longitudinal axis, and
first and second abrasive elements attached to a distal end portion
of the drive shaft and each having a center of mass offset from the
longitudinal axis, the center of mass of the first abrasive element
being offset from the longitudinal axis at a first radial angle,
the center of mass of the second abrasive element being offset from
the longitudinal axis at a second radial angle that differs from
the first radial angle. The method further includes rotating the
drive shaft about the longitudinal axis such that the abrasive
elements orbit around the longitudinal axis.
[0009] One or more of the methods can further include the
embodiments described herein. In some embodiments, the method can
include translationally moving the drive shaft along the
longitudinal axis. The method can include modifying a speed of the
drive shaft. Modifying the speed of the drive shaft can include
modifying a diameter of rotation. In some embodiments, delivering
the rotational atherectomy device can include delivering the
rotational atherectomy device with a distal portion of the
rotational atherectomy device positioned toward a vein of the
patient. Delivering the rotational atherectomy device can include
delivering the rotational atherectomy device with a distal portion
of the rotational atherectomy device positioned toward an artery of
the patient to treat a lesion at an arterial anastomosis. In some
embodiments, the method can further include inflating an inflatable
member on the rotational atherectomy device. In some embodiments,
the rotational atherectomy device can further include a distal
stability element affixed to the drive shaft and having a center of
mass aligned with the longitudinal axis, the distal stability
element distally spaced apart from the plurality of abrasive
elements.
[0010] In yet another aspect, this disclosure is directed to a
device for performing rotational atherectomy to remove stenotic
lesion material from an arteriovenous graft of a patient. The
device includes means for causing rotation along a longitudinal
axis of the device, a first means for removing stenotic lesion
material from the arteriovenous graft of the patient, the first
means having a first center of mass offset from the longitudinal
axis at a first radial angle, a second means for removing stenotic
lesion material from the arteriovenous graft of the patient, the
second means having a second center of mass offset from the
longitudinal axis at a second radial angle that differs from the
first radial angle, and means for mounting the means for
transmitting, the first means, and the second means.
[0011] In some embodiments, the device can further include a third
means for removing stenotic lesion material from the arteriovenous
graft of the patient, the third means having a third center of mass
offset from the longitudinal axis at a third radial angle that
differs from the first radial angle and the second radial angle. In
some embodiments, the second radial angle differs from the first
radial angle by at least 15 degrees, and the third radial angle
differs from the first radial angle and the second radial angle by
at least 15 degrees. In some embodiments, a proximal-most one of
the means for removing stenotic lesion material and a distal-most
means for removing stenotic lesion material are each smaller than
intermediate ones of the means for removing stenotic lesion
material. In some embodiments, the means for stabilizing include
means for removing stenotic lesion material. In some embodiments,
the device further includes means for receiving a guidewire along
the longitudinal axis. In some embodiments, the device also
includes means for causing translational movement of the device
along the longitudinal axis. In some embodiments, the device
includes means for extending a distal portion of the device. In
some embodiments, the device further includes means for stabilizing
the means for mounting, the means for stabilizing having a center
of mass aligned with the longitudinal axis.
[0012] Some of the embodiments described herein may provide one or
more of the following advantages. First, some embodiments of the
rotational atherectomy devices and systems operate with a stable
and predictable rotary motion profile for an atherectomy procedure
applied to an implanted graft (e.g., synthetic AV graft) for the
removal of stenotic plaque-like lesions from within the graft. That
is, when the device is being rotated in operation, the eccentric
abrasive element(s) follows a predefined, consistent orbital path
(offset from an axis of rotation of the device) while the stability
element(s) and other portions of the device remain on or near to
the axis of rotation for the drive shaft in a stable manner. This
predictable orbital motion profile can be attained by the use of
design features including, but not limited to, stability element(s)
that have centers of mass that are coaxial with the longitudinal
axis of the drive shaft, a polymeric coating on at least a portion
of the drive shaft, a distal-most drive shaft extension portion,
and the like. Some embodiments of the rotational atherectomy
devices and systems provided herein may include one or more of such
design features.
[0013] Second, the rotational atherectomy devices provided herein
may include a distal stability element that has an abrasive outer
surface that allows a rotational atherectomy device, when being
advanced within an implanted graft, to treat plaque-like lesions
that occlude or substantially occlude the graft. In such
applications, the abrasive outer surface on the distal stability
element may help facilitate passage of the distal stability element
through plaque-like lesions that occlude or substantially occlude
the graft. In some such cases, the drive shaft may be used to
rotate the distal stability element to help facilitate boring of
the distal stability element through such lesions in a drill-like
fashion.
[0014] Third, some embodiments of the rotational atherectomy
devices and systems provided herein can be used to treat various
graft sizes (e.g., large-diameter grafts having an internal
diameter that is multiple time greater than the outer diameter of
the abrasive element) while, in some embodiments, using a small
introducer sheath size for delivery of the devices and systems. In
other words, in some embodiments the rotating eccentric abrasive
element(s) traces an orbital path that is substantially larger than
the outer diameter of the rotational atherectomy device in the
non-rotating state. This feature improves the ability of the
rotational atherectomy devices provided herein to treat, in some
embodiments, very large grafts while still fitting within a small
introducer size. In some embodiments, this feature can be at least
partially attained by using a helical array of abrasive elements
that has a high eccentric mass (e.g., the centers of mass of the
abrasive elements are significantly offset from the central
longitudinal axis of the drive shaft). Further, in some embodiments
this feature can be at least partially attained by using multiple
abrasive elements that are radially offset from each other around
the drive shaft such that the centers of the abrasive elements are
not coaxial with each other.
[0015] Fourth, in some embodiments rotational atherectomy systems
described herein include user controls that are convenient and
straight-forward to operate. In one such example, the user controls
can include selectable elements that correspond to the diametric
size of the implanted graft(s) to be treated. When the
clinician-user selects the particular graft size, the system will
determine an appropriate rpm of the drive shaft to obtain the
desired orbit of the abrasive element(s) for the particular graft
size. Hence, in such a case the clinician-user conveniently does
not need to explicitly select or control the rpm of the drive
shaft. In another example, the user controls can include selectable
elements that correspond to the speed of drive shaft rotations. In
some such examples, the user can conveniently select "low,"
"medium," or "high" speeds.
[0016] The details of one or more embodiments of the invention are
set forth in the accompanying drawings and the description below.
Other features, objects, and advantages of the invention will be
apparent from the description and drawings, and from the
claims.
DESCRIPTION OF DRAWINGS
[0017] FIG. 1 shows an example rotational atherectomy system that
is being used to perform a rotational atherectomy procedure in an
arm of a patient.
[0018] FIG. 2 shows the example rotational atherectomy device of
FIG. 1 within a region of a lesion in a graft located in an arm of
a patient.
[0019] FIG. 3 shows the example rotational atherectomy device of
FIG. 1 within a region of a lesion in a graft located in an arm of
a patient.
[0020] FIG. 4 shows the example rotational atherectomy device of
FIG. 1 within a region of a lesion in a graft located in a chest of
a patient.
[0021] FIG. 5 shows the example rotational atherectomy device of
FIG. 1 within a region of a lesion in a graft located in a torso of
a patient.
[0022] FIG. 6 shows an example user control unit of a rotational
atherectomy system being operated by a clinician-user to perform a
rotational atherectomy procedure above the knee of a patient.
[0023] FIG. 7 shows the example rotational atherectomy device of
FIG. 1 within the region of the lesion.
[0024] FIG. 8 shows the rotational atherectomy device of FIG. 1
with the abrasive element being rotated with a first diameter of
orbit at a first longitudinal position.
[0025] FIG. 9 shows the rotational atherectomy device of FIG. 1
with the abrasive element being rotated with a second diameter of
orbit at the first longitudinal position.
[0026] FIG. 10 shows the rotational atherectomy device of FIG. 1
with the abrasive element being rotated with the second diameter of
orbit at a second longitudinal position.
[0027] FIG. 11 shows the example rotational atherectomy device of
FIG. 1 in use at a first longitudinal position in the region of the
lesion. A multi-portion abrasive element of the rotational
atherectomy device is being rotated along an orbital path to abrade
the lesion.
[0028] FIG. 12 shows the rotational atherectomy device of FIG. 1
with the abrasive element being rotated at a second longitudinal
position that is distal of the first longitudinal position.
[0029] FIG. 13 shows the rotational atherectomy device of FIG. 1
with the abrasive element being rotated at a third longitudinal
position that is distal of the second longitudinal position.
[0030] FIG. 14 is a longitudinal cross-sectional view of a distal
portion of an example rotational atherectomy device showing a
multi-portion abrasive element and a distal stability element with
an abrasive coating.
[0031] FIG. 15 is a side view of a distal portion of another
example rotational atherectomy device showing a multi-portion
abrasive element and a distal stability element with an abrasive
coating. The individual portions of the multi-portion abrasive
element are offset from each other around the drive shaft such that
the centers of mass of the abrasive element portions define a
spiral path around the drive shaft axis.
[0032] FIG. 16 is a transverse cross-sectional view of the
rotational atherectomy device of FIG. 15 taken along the
cutting-plane line 16-16.
[0033] FIG. 17 is a transverse cross-sectional view of the
rotational atherectomy device of FIG. 15 taken along the
cutting-plane line 17-17.
[0034] FIG. 18 is a transverse cross-sectional view of the
rotational atherectomy device of FIG. 15 taken along the
cutting-plane line 18-18.
[0035] FIG. 19 is a transverse cross-sectional view of the
rotational atherectomy device of FIG. 15 taken along the
cutting-plane line 19-19.
[0036] FIG. 20 is a transverse cross-sectional view of the
rotational atherectomy device of FIG. 15 taken along the
cutting-plane line 20-20.
[0037] Like reference symbols in the various drawings indicate like
elements.
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
[0038] Referring to FIG. 1, in some embodiments a rotational
atherectomy system 100 for removing or reducing stenotic lesions in
implanted grafts 32 (e.g., a synthetic AV graft) can include a
rotational atherectomy device 170 and a controller 150. In some
embodiments, the rotational atherectomy device 170 can include a
guidewire 134, an actuator handle assembly 110, and an elongate
flexible drive shaft assembly 130. The drive shaft assembly 130
extends distally from the handle assembly 110. The controller 150
can be connected to the handle assembly 110 via a cable assembly
160. The handle assembly 110 and controller 150 can be operated by
a clinician to perform and control the rotational atherectomy
procedure. In some embodiments, the actuator handle assembly 110
can be an electric handle that includes an electric motor, and can
include speed controls, actuator buttons, and other functions to
perform and control the rotational atherectomy procedure.
[0039] In the depicted embodiment, the elongate flexible drive
shaft assembly 130 includes a sheath 132 and a flexible drive shaft
136. A proximal end of the sheath 132 is fixed to a distal end of
the handle assembly 110. The flexible drive shaft 136 is slidably
and rotatably disposed within a lumen of the sheath 132. The
flexible drive shaft 136 defines a longitudinal lumen in which the
guidewire 134 is slidably disposed. As depicted, the flexible drive
shaft 136 includes a torque-transmitting coil that defines the
longitudinal lumen along a central longitudinal axis, and the drive
shaft 136 is configured to rotate about the longitudinal axis while
the sheath 132 remains generally stationary. Hence, as described
further below, during a rotational atherectomy procedure the
flexible drive shaft 136 is in motion (e.g., rotating and
longitudinally translating) while the sheath 132 and the guidewire
134 are generally stationary.
[0040] The rotational atherectomy device 170 can include one or
more abrasive elements 138 that are eccentrically-fixed to the
drive shaft 136 proximal of a distal stability element 140. In some
embodiments, the distal stability element 140 is
concentrically-fixed to the drive shaft 136 between the one or more
abrasive elements 138 and a distal drive shaft extension portion.
As such, the center of mass of the distal stability element 140 is
aligned with the central axis of the drive shaft 136 while the
center of mass of each abrasive element 138 is offset from the
central axis of the drive shaft 136.
[0041] Still referring to FIG. 1, the graft 32 to be treated is in
an arm 12 of a patient 10. For example, the graft 32 may be located
below an elbow of the patient 10. In the depicted example, the
graft 32 is a loop graft 32. In some embodiments, the distal
portion of the rotational atherectomy device 170 is introduced into
the vasculature by penetrating through a wall of the graft 32. In
some embodiments, the graft 32 may be connecting a radial artery or
a brachial artery 34 to a median cubital vein or a basilic vein 36.
As shown in the depicted embodiment, the rotational atherectomy
device 170 is inserted such that a distal portion of the rotational
atherectomy device 170 is pointed toward a venous vessel, such as a
median cubital or basilic vein 36. The abrasive elements 138 on the
drive shaft 136 of the rotational atherectomy device 170 can be
rotated to remove one or more lesions in the graft 32.
[0042] In some embodiments, the graft 32 is a self-healing graft,
such that punctures in the graft caused by insertion of the
rotational atherectomy device 170 will close and heal without
additional aid. In some embodiments, the graft 32 can have an outer
diameter of from about 4 millimeters (mm) to about 8 mm.
[0043] Referring to FIG. 2, in another example, the graft 32 to be
treated is in an arm 12 of a patient 10. For example, the graft 32
may be located below an elbow of the patient 10. In the depicted
example, the graft 32 is a straight graft 32. In some embodiments,
the graft 32 may be connecting a radial artery 34 to one of a
median cubital vein, a basilic vein, or a cephalic vein 36. In some
embodiments, the rotational atherectomy device 170 can be inserted
such that a distal portion of the rotational atherectomy device 170
is pointed toward the median cubital vein, the basilic vein, or the
cephalic vein 36. The abrasive elements on the rotational
atherectomy device 170 can be rotated to remove a lesion in the
graft 32.
[0044] Referring to FIG. 3, in some embodiments, the graft 32 to be
treated is in an arm 12 of a patient 10. For example, the graft 32
may be located below an elbow of the patient 10. In some examples,
the graft 32 is a loop graft 32. In some embodiments, the graft 32
may be connecting a radial artery or a brachial artery 34 to a
median cubital vein or a basilic vein 36. In some embodiments, the
rotational atherectomy device 170 can be inserted such that a
distal portion of the rotational atherectomy device 170 is pointed
toward the median cubital vein or the basilic vein 36. The abrasive
elements on the rotational atherectomy device 170 can be rotated to
remove a lesion in the graft 32.
[0045] Referring to FIG. 4, in some examples, the graft 32 to be
treated is in a torso 14 of a patient 10. For example, the graft 32
may be located across a chest of the patient 10. In some
embodiments, the graft 32 may be connecting an axillary artery 34
to an axillary vein 36. In the depicted embodiment, the rotational
atherectomy device 170 can be inserted such that a distal portion
of the rotational atherectomy device 170 is pointed toward the
axillary vein 36. The abrasive elements on the rotational
atherectomy device 170 can be rotated to remove a lesion in the
graft 32.
[0046] Referring to FIG. 5, in some examples, the graft 32 to be
treated is in a torso 14 of a patient 10. In some embodiments, the
graft 32 may be connecting an axillary artery 34 to a saphenous
vein 36 of the patient 10. In the depicted embodiment, the
rotational atherectomy device 170 can be inserted such that a
distal portion of the rotational atherectomy device 170 is pointed
toward the saphenous vein 36. The abrasive elements on the
rotational atherectomy device 170 can be rotated to remove a lesion
in the graft 32.
[0047] Referring back to FIG. 1, in some optional embodiments, an
inflatable member (not shown) can surround a distal end portion of
the sheath 132. Such an inflatable member can be selectively
expandable between a deflated low-profile configuration and an
inflated deployed configuration. The sheath 132 may define an
inflation lumen through which the inflation fluid can pass (to and
from the optional inflatable member). The inflatable member can be
in the deflated low-profile configuration during the navigation of
the drive shaft assembly 130 through the patient's graft to a
target location. Then, at the target location, the inflatable
member can be inflated so that the outer diameter of the inflatable
member contacts the wall of the vessel. In that arrangement, the
inflatable member advantageously stabilizes the drive shaft
assembly 130 in the vessel during the rotational atherectomy
procedure.
[0048] Still referring to FIG. 1, the flexible drive shaft 136 is
slidably and rotatably disposed within a lumen of the sheath 132. A
distal end portion of the drive shaft 136 extends distally of the
distal end of the sheath 132 such that the distal end portion of
the drive shaft 136 is exposed (e.g., not within the sheath 132, at
least not during the performance of the actual rotational
atherectomy).
[0049] In the depicted embodiment, the exposed distal end portion
of the drive shaft 136 includes one or more abrasive elements 138,
a (optional) distal stability element 140, and a distal drive shaft
extension portion 142. In the depicted embodiment, the one or more
abrasive elements 138 are eccentrically-fixed to the drive shaft
136 proximal of the distal stability element 140. In this
embodiment, the distal stability element 140 is
concentrically-fixed to the drive shaft 136 between the one or more
abrasive elements 138 and the distal drive shaft extension portion
142. As such, the center of mass of the distal stability element
140 is aligned with the central axis of the drive shaft 136 while
the center of mass of each abrasive element 138 is offset from the
central axis of the drive shaft 136. The distal drive shaft
extension portion 142, which includes the torque-transmitting coil,
is configured to rotate about the longitudinal axis extends
distally from the distal stability element 140 and terminates at a
free end of the drive shaft 136.
[0050] In some optional embodiments, a proximal stability element
(not shown) is included. The proximal stability element can be
constructed and configured similarly to the depicted embodiment of
the distal stability element 140 (e.g., a metallic cylinder
directly coupled to the torque-transmitting coil of the drive shaft
136 and concentric with the longitudinal axis of the drive shaft
136) while being located proximal to the one or more abrasive
elements 138.
[0051] In the depicted embodiment, the distal stability element 140
has a center of mass that is axially aligned with a central
longitudinal axis of the drive shaft 136, while the one or more
abrasive elements 138 (collectively and/or individually) have a
center of mass that is axially offset from central longitudinal
axis of the drive shaft 136. Accordingly, as the drive shaft 136 is
rotated about its longitudinal axis, the principle of centrifugal
force will cause the one or more abrasive elements 138 (and the
portion of the drive shaft 136 to which the one or more abrasive
elements 138 are affixed) to follow a transverse generally circular
orbit (e.g., somewhat similar to a "jump rope" orbital movement)
relative to the central axis of the drive shaft 136 (as described
below, for example, in connection with FIGS. 11-13). In general,
faster speeds (rpm) of rotation of the drive shaft 136 will result
in larger diameters of the orbit (within the limits of the graft
diameter). The orbiting one or more abrasive elements 138 will
contact the stenotic lesion to ablate or abrade the lesion to a
reduced size (i.e., small particles of the lesion will be abraded
from the lesion).
[0052] The rotating distal stability element 140 will remain
generally at the longitudinal axis of the drive shaft 136 as the
drive shaft 136 is rotated (as described below, for example, in
connection with FIGS. 11-13). In some optional embodiments, two or
more distal stability elements 140 are included. As described
further below, contemporaneous with the rotation of the drive shaft
136, the drive shaft 136 can be translated back and forth along the
longitudinal axis of the drive shaft 136. Hence, lesions can be
abraded radially and longitudinally by virtue of the orbital
rotation and translation of the one or more abrasive elements 138,
respectively.
[0053] The flexible drive shaft 136 of rotational atherectomy
system 100 is laterally flexible so that the drive shaft 136 can
readily conform to the non-linear grafts of the patient, and so
that a portion of the drive shaft 136 at and adjacent to the one or
more abrasive elements 138 will laterally deflect when acted on by
the centrifugal forces resulting from the rotation of the one or
more eccentric abrasive elements 138. In this embodiment, the drive
shaft 136 comprises one or more helically wound wires (or filars)
that provide one or more torque-transmitting coils of the drive
shaft 136 (as described below, for example, in connection with
FIGS. 14-15). In some embodiments, the one or more helically wound
wires are made of a metallic material such as, but not limited to,
stainless steel (e.g., 316, 316L, or 316LVM), nitinol, titanium,
titanium alloys (e.g., titanium beta 3), carbon steel, or another
suitable metal or metal alloy. In some alternative embodiments, the
filars are or include graphite, Kevlar, or a polymeric material. In
some embodiments, the filars can be woven, rather than wound. In
some embodiments, individual filars can comprise multiple strands
of material that are twisted, woven, or otherwise coupled together
to form a filar. In some embodiments, the filars have different
cross-sectional geometries (size or shape) at different portions
along the axial length of the drive shaft 136. In some embodiments,
the filars have a cross-sectional geometry other than a circle,
e.g., an ovular, square, triangular, or another suitable shape.
[0054] In this embodiment, the drive shaft 136 has a hollow core.
That is, the drive shaft 136 defines a central longitudinal lumen
running therethrough. The lumen can be used to slidably receive the
guidewire 134 therein, as will be described further below. In some
embodiments, the lumen can be used to aspirate particulate or to
convey fluids that are beneficial for the atherectomy
procedure.
[0055] In some embodiments, the drive shaft 136 includes an
optional coating on one or more portions of the outer diameter of
the drive shaft 136. The coating may also be described as a jacket,
a sleeve, a covering, a casing, and the like. In some embodiments,
the coating adds column strength to the drive shaft 136 to
facilitate a greater ability to push the drive shaft 136 through
stenotic lesions. In addition, the coating can enhance the
rotational stability of the drive shaft 136 during use. In some
embodiments, the coating is a flexible polymer coating that
surrounds an outer diameter of the coil (but not the abrasive
elements 138 or the distal stability element 140) along at least a
portion of drive shaft 136 (e.g., the distal portion of the drive
shaft 136 exposed outwardly from the sheath 132). In some
embodiments, a portion of the drive shaft 136 or all of the drive
shaft 136 is uncoated. In particular embodiments, the coating is a
fluid impermeable material such that the lumen of the drive shaft
136 provides a fluid impermeable flow path along at least the
coated portions of the drive shaft 136.
[0056] The coating may be made of materials including, but not
limited to, PEBEX, PICOFLEX, PTFE, ePTFE, FEP, PEEK, silicone, PVC,
urethane, polyethylene, polypropylene, and the like, and
combinations thereof. In some embodiments, the coating covers the
distal stability element 140 and the distal extension portion 142,
thereby leaving only the one or more abrasive elements 138 exposed
(non-coated) along the distal portion of the drive shaft 136. In
alternative embodiments, the distal stability element 140 is not
covered with the coating, and thus would be exposed like the
abrasive elements 138. In some embodiments, two or more layers of
the coating can be included on portions of the drive shaft 136.
Further, in some embodiments different coating materials (e.g.,
with different durometers and/or stiffnesses) can be used at
different locations on the drive shaft 136.
[0057] In the depicted embodiment, the distal stability element 140
is a metallic cylindrical member having an inner diameter that
surrounds a portion of the outer diameter of the drive shaft 136.
In some embodiments, the distal stability element 140 has a
longitudinal length that is greater than a maximum exterior
diameter of the distal stability element 140. In the depicted
embodiment, the distal stability element 140 is coaxial with the
longitudinal axis of the drive shaft 136. Therefore, the center of
mass of the distal stability element 140 is axially aligned
(non-eccentric) with the longitudinal axis of the drive shaft 136.
In alternative rotational atherectomy device embodiments, stability
element(s) that have centers of mass that are eccentric in relation
to the longitudinal axis may be included in addition to, or as an
alternative to, the coaxial stability elements 140. For example, in
some alternative embodiments, the stability element(s) can have
centers of mass that are eccentric in relation to the longitudinal
axis and that are offset 180 degrees (or otherwise oriented) in
relation to the center of mass of the one or more abrasive elements
138.
[0058] The distal stability element 140 may be made of a suitable
biocompatible material, such as a higher-density biocompatible
material. For example, in some embodiments the distal stability
element 140 may be made of metallic materials such as stainless
steel, tungsten, molybdenum, iridium, cobalt, cadmium, and the
like, and alloys thereof. The distal stability element 140 has a
fixed outer diameter. That is, the distal stability element 140 is
not an expandable member in the depicted embodiment. The distal
stability element 140 may be mounted to the filars of the drive
shaft 136 using a biocompatible adhesive, by welding, by press
fitting, and the like, and by combinations thereof. The coating may
also be used in some embodiments to attach or to supplement the
attachment of the distal stability element 140 to the filars of the
drive shaft 136. Alternatively, the distal stability element 140
can be integrally formed as a unitary structure with the filars of
the drive shaft 136 (e.g., using filars of a different size or
density, using filars that are double-wound to provide multiple
filar layers, or the like). The maximum outer diameter of the
distal stability element 140 may be smaller than the maximum outer
diameters of the one or more abrasive elements 138.
[0059] In some embodiments, the distal stability element 140 has an
abrasive coating on its exterior surface. For example, in some
embodiments a diamond coating (or other suitable type of abrasive
coating) is disposed on the outer surface of the distal stability
element 140. In some cases, such an abrasive surface on the distal
stability element 140 can help facilitate the passage of the distal
stability element 140 through vessel restrictions (such as
calcified areas of a blood vessel).
[0060] In some embodiments, the distal stability element 140 has an
exterior cylindrical surface that is smoother and different from an
abrasive exterior surface of the one or more abrasive elements 138.
That may be the case whether or not the distal stability element
140 have an abrasive coating on its exterior surface. In some
embodiments, the abrasive coating on the exterior surface of the
distal stability element 140 is rougher than the abrasive surfaces
on the one or more abrasive elements 138.
[0061] Still referring to FIG. 1, the one or more abrasive elements
138 (which may also be referred to as a burr, multiple burrs, or
(optionally) a helical array of burrs) can comprise a biocompatible
material that is coated with an abrasive media such as diamond
grit, diamond particles, silicon carbide, and the like. In the
depicted embodiment, the abrasive elements 138 includes a total of
five discrete abrasive elements that are spaced apart from each
other. In some embodiments, one, two, three, four, five, six,
seven, eight, nine, ten, eleven, twelve, thirteen, fourteen,
fifteen, or more than fifteen discrete abrasive elements are
included as the one or more abrasive elements 138. Each of the five
discrete abrasive elements can include the abrasive media coating,
such as a diamond grit coating.
[0062] In the depicted embodiment, the two outermost abrasive
elements are smaller in maximum diameter than the three inner
abrasive elements. In some embodiments, all of the abrasive
elements are the same size. In particular embodiments, three or
more different sizes of abrasive elements are included. Any and all
such possible arrangements of sizes of abrasive elements are
envisioned and within the scope of this disclosure.
[0063] Also, in the depicted embodiment, the center of mass of each
abrasive element 138 is offset from the longitudinal axis of the
drive shaft 136. Therefore, as the eccentric one or more abrasive
elements 138 are rotated (along an orbital path), at least a
portion of the abrasive surface of the one or more abrasive
elements 138 can make contact with surrounding stenotic lesion
material. As with the distal stability element 140, the eccentric
one or more abrasive elements 138 may be mounted to the filars of
the torque-transmitting coil of the drive shaft 136 using a
biocompatible adhesive, high temperature solder, welding, press
fitting, and the like. In some embodiments, a hypotube is crimped
onto the drive shaft and an abrasive element is laser welded to the
hypotube. Alternatively, the one or more abrasive elements 138 can
be integrally formed as a unitary structure with the filars of the
drive shaft 136 (e.g., using filars that are wound in a different
pattern to create an axially offset structure, or the like).
[0064] In some embodiments, the spacing of the distal stability
element 140 relative to the one or more abrasive elements 138 and
the length of the distal extension portion 142 can be selected to
advantageously provide a stable and predictable rotary motion
profile during high-speed rotation of the drive shaft 136. For
example, in embodiments that include the distal drive shaft
extension portion 142, the ratio of the length of the distal drive
shaft extension 142 to the distance between the centers of the one
or more abrasive elements 138 and the distal stability element 140
is about 1:0.5, about 1:0.8, about 1:1, about 1.1:1, about 1.2:1,
about 1.5:1, about 2:1, about 2.5:1, about 3:1, or higher than
3:1.
[0065] Still referring to FIG. 1, the rotational atherectomy system
100 also includes the actuator handle assembly 110. The actuator
handle assembly 110 includes a housing and a carriage assembly. The
carriage assembly is slidably translatable along the longitudinal
axis of the handle assembly 110 as indicated by the arrow 115. For
example, in some embodiments the carriage assembly can be
translated, without limitation, about 8 cm to about 12 cm, or about
6 cm to about 10 cm, or about 4 cm to about 8 cm, or about 6 cm to
about 14 cm. As the carriage assembly is translated in relation to
the housing, the drive shaft 136 translates in relation to the
sheath 132 in a corresponding manner.
[0066] In the depicted embodiment, the carriage assembly includes a
valve actuator. In some embodiments, an electric motor for driving
rotations of the drive shaft 136 is coupled to the carriage
assembly such that the valve actuator is an electrical switch
instead. In the depicted embodiment, the valve actuator is a button
that can be depressed to actuate a compressed gas control valve
(on/off; defaulting to off) mounted to the carriage assembly. While
the valve actuator is depressed, a compressed gas (e.g., air,
nitrogen, etc.) is supplied through the valve to a turbine member
that is rotatably coupled to the carriage assembly and fixedly
coupled to the drive shaft 136. Hence, an activation of the valve
actuator will result in a rotation of the turbine member and, in
turn, the drive shaft 136 (as depicted by arrow 137). In some
embodiments, the rotational atherectomy system 100 is configured to
rotate the drive shaft 136 at a high speed of rotation (e.g.,
20,000-160,000 rpm) such that the eccentric one or more abrasive
elements 138 revolve in an orbital path to thereby contact and
remove portions of a target lesion (even those portions of the
lesion that are spaced farther from the axis of the drive shaft 136
than the maximum radius of the one or more abrasive elements
138).
[0067] To operate the handle assembly 110 during a rotational
atherectomy procedure, a clinician can grasp the carriage assembly
and depress the valve actuator with the same hand. The clinician
can move (translate) the carriage assembly distally and proximally
by hand (e.g., back and forth in relation to the housing), while
maintaining the valve actuator in the depressed state. In that
manner, a target lesion(s) can be ablated radially and
longitudinally by virtue of the resulting orbital rotation and
translation of the one or more abrasive elements 138,
respectively.
[0068] During an atherectomy treatment, in some cases the guidewire
134 is left in position in relation to the drive shaft 136
generally as shown. For example, in some cases the portion of the
guidewire 134 that is extending beyond the distal end of the drive
shaft 136 (or extension portion 142) is about 4 inches to about 8
inches (about 10 cm to about 20 cm), about 8 inches to about 12
inches (about 20 cm to about 30 cm), about 4 inches to about 16
inches (about 10 cm to about 40 cm), or about 2 inches to about 20
inches (about 5 cm to about 50 cm). In some cases, the guidewire
134 is pulled back to be within (while not extending distally from)
the drive shaft 136 during an atherectomy treatment. The distal end
of the guidewire 134 may be positioned anywhere within the drive
shaft 136 during an atherectomy treatment. In some cases, the
guidewire 134 may be completely removed from within the drive shaft
during an atherectomy treatment. The extent to which the guidewire
134 is engaged with the drive shaft 136 during an atherectomy
treatment may affect the size of the orbital path of the one or
more abrasive elements 138.
[0069] In the depicted embodiment, the handle assembly 110 also
includes a guidewire detention mechanism 118. The guidewire
detention mechanism 118 can be selectively actuated (e.g., rotated)
to releasably clamp and maintain the guidewire 134 in a stationary
position relative to the handle assembly 110 (and, in turn,
stationary in relation to rotations of the drive shaft 136 during
an atherectomy treatment). While the drive shaft 136 and handle
assembly 110 are being advanced over the guidewire 134 to put the
one or more abrasive elements 138 into a targeted position within a
patient's graft 32, the guidewire detention mechanism 118 will be
unactuated so that the handle assembly 110 is free to slide in
relation to the guidewire 134. Then, when the clinician is ready to
begin the atherectomy treatment, the guidewire detention mechanism
118 can be actuated to releasably detain/lock the guidewire 134 in
relation to the handle assembly 110. That way the guidewire 134
will not rotate while the drive shaft 136 is rotating, and the
guidewire 134 will not translate while the carriage assembly is
being manually translated.
[0070] Still referring to FIG. 1, the rotational atherectomy system
100 also includes the controller 150. In the depicted embodiment,
the controller 150 includes a user interface that includes a
plurality of selectable inputs that correspond to a plurality of
vessel sizes (diameters). To operate the rotational atherectomy
system 100, the user can select a particular one of the selectable
inputs that corresponds to the diameter of the vessel being
treated. In response, the controller 150 will determine the
appropriate gas pressure for rotating the drive shaft 136 in a
vessel of the selected diameter (faster rpm for larger vessels and
slower rpm for smaller vessel), and supply the gas at the
appropriate pressure to the handle assembly 110.
[0071] In some embodiments, the controller 150 is pole-mounted. The
controller 150 can be used to control particular operations of the
handle assembly 110 and the drive shaft assembly 130. For example,
the controller 150 can be used to compute, display, and adjust the
rotational speed of the drive shaft 136.
[0072] In some embodiments, the controller 150 can include
electronic controls that are in electrical communication with a
turbine RPM sensor located on the carriage assembly. The controller
150 can convert the signal(s) from the sensor into a corresponding
RPM quantity and display the RPM on the user interface. If a speed
adjustment is desired, the clinician can increase or decrease the
rotational speed of the drive shaft 136. In result, a flow or
pressure of compressed gas supplied from the controller 150 to the
handle assembly 110 (via the cable assembly 160) will be modulated.
The modulation of the flow or pressure of the compressed gas will
result in a corresponding modulation of the RPM of the turbine
member and of the drive shaft 136.
[0073] In some embodiments, the controller 150 includes one or more
interlock features that can enhance the functionality of the
rotational atherectomy system 100. In one such example, if the
controller 150 does not detect any electrical signal (or a proper
signal) from the turbine RPM sensor, the controller 150 can
discontinue the supply of compressed gas. In another example, if a
pressure of a flush liquid supplied to the sheath 132 is below a
threshold pressure value, the controller 150 can discontinue the
supply of compressed gas.
[0074] Still referring to FIG. 1, the rotational atherectomy system
100 can include an electric handle with an electric motor. In some
embodiments, the electric handle can include a user interface that
includes a plurality of selectable inputs that correspond to a
plurality of vessel sizes (diameters). To operate the rotational
atherectomy system 100, the user can select a particular one of the
selectable inputs that corresponds to the diameter of the vessel
being treated. In response, the electric handle will determine the
appropriate rpm for rotating the drive shaft 136 in a vessel of the
selected diameter (faster rpm for larger vessels and slower rpm for
smaller vessel), and operate the electric motor accordingly.
[0075] Referring to FIG. 6, the rotational atherectomy system 100
also includes the controller 150. In the depicted embodiment, the
controller 150 includes a user interface that includes a plurality
of selectable inputs that correspond to a plurality of graft sizes
(diameters). Other types of user interfaces are also envisioned. To
operate the rotational atherectomy system 100, the user can select
a particular one of the selectable inputs that corresponds to the
diameter of the graft being treated. In response, the controller
150 will determine the appropriate gas pressure for rotating the
one or more abrasive elements 138 in a graft of the selected
diameter (faster RPM for larger grafts and slower RPM for smaller
grafts), and supply the gas at the appropriate pressure to the
handle assembly 110. In some embodiments, the driver for rotation
of the one or more abrasive elements 138 is an electrical motor
rather than the pneumatic motor included in the depicted example.
In the depicted example, the graft 32 to be treated is in a leg 16
of a patient. In particular, the graft 32 is above a knee (e.g.,
between a femoral artery and a saphenous vein, without
limitation).
[0076] In some embodiments, the user interface is configured such
that the user can simply select either "LOW," "MED," or "HIGH"
speed via the selectable inputs. Based on the user's selection of
either "LOW," "MED," or "HIGH," the controller 150 will provide a
corresponding output for rotating the drive shaft at a
corresponding rotational speed. It should be understood that the
user interfaces are merely exemplary and non-limiting. That is,
other types of user interface controls can also be suitably used,
and are envisioned within the scope of this disclosure.
[0077] Referring to FIGS. 7-13, the rotational atherectomy system
100 can be used to treat a graft 32 having a stenotic lesion 40
along an inner wall 38 of the graft 32. The rotational atherectomy
system 100 is used to fully or partially remove the stenotic lesion
40, thereby removing or reducing the blockage within the graft 32
caused by the stenotic lesion 40. By performing such a treatment,
the blood flow through the graft 32 may be thereafter increased or
otherwise improved. The graft 32 and lesion 40 are shown in
longitudinal cross-sectional views to enable visualization of the
rotational atherectomy system 100.
[0078] Briefly, in some implementations the following activities
may occur to achieve the deployed arrangement shown in FIGS. 7-13.
In some embodiments, an introducer sheath (not shown) can be
percutaneously advanced into the vasculature of the patient. The
guidewire 134 can then be inserted through a lumen of the
introducer sheath and navigated within the patient's graft 32 to a
target location (e.g., the location of the lesion 40). Techniques
such as x-ray fluoroscopy or ultrasonic imaging may be used to
provide visualization of the guidewire 134 and other atherectomy
system components during placement. In some embodiments, no
introducer sheath is used and the guidewire 134 is inserted without
assistance from a sheath.
[0079] Next, portions of the rotational atherectomy system 100 can
be inserted over the guidewire 134. For example, an opening to the
lumen of the drive shaft 136 at the distal free end of the drive
shaft 136 (e.g., at the distal end of the optional distal drive
shaft extension portion 142) can be placed onto the guidewire 134,
and then the drive shaft assembly 130 and handle assembly 110 can
be gradually advanced over the guidewire 134 to the position in
relation to the lesion 40. In some cases, the drive shaft 136 is
disposed fully within the lumen of the sheath 132 during the
advancing. In some cases, a distal end portion of the drive shaft
136 extends from the distal end opening 143 of the sheath 132
during the advancing. Eventually, after enough advancing, the
proximal end of the guidewire 134 will extend proximally from the
handle assembly 110 (via the access port 120 defined by the handle
housing).
[0080] In some cases (such as in the depicted example), the lesion
40 may be so large (i.e., so extensively occluding the vessel 10)
that it is difficult or impossible to push the distal stability
element 140 through the lesion 40. In some such cases, an abrasive
outer surface on the distal stability element 140 can be used to
help facilitate passage of the distal stability element 140 into or
through the lesion 40. In some such cases, the drive shaft 136 can
be rotated to further help facilitate the distal stability element
140 to bore into/through the lesion 40.
[0081] Next, as depicted by FIGS. 11-13, the rotation and
translational motions of the drive shaft 136 (and the one or more
abrasive elements 138) can be commenced to perform ablation of the
lesion 40.
[0082] In some implementations, prior to the ablation of the lesion
40 by the one or more abrasive elements 138, an inflatable member
can be used as an angioplasty balloon to treat the lesion 40. That
is, an inflatable member (on the sheath 132, for example) can be
positioned within the lesion 40 and then inflated to compress the
lesion 40 against the inner wall 38 of the graft 32. Thereafter,
the rotational atherectomy procedure can be performed. In some
implementations, such an inflatable member can be used as an
angioplasty balloon after the rotational atherectomy procedure is
performed. In some implementations, additionally or alternatively,
a stent can be placed at lesion 40 using an inflatable member on
the sheath 132 (or another balloon member associated with the drive
shaft assembly 130) after the rotational atherectomy procedure is
performed.
[0083] The guidewire 134 may remain extending from the distal end
of the drive shaft 136 during the atherectomy procedure as shown.
For example, as depicted by FIGS. 11-13, the guidewire 134 extends
through the lumen of the drive shaft 136 and further extends
distally of the distal end of the distal extension portion 142
during the rotation and translational motions of the drive shaft
136 (refer, for example, to FIGS. 11-13). In some alternative
implementations, the guidewire 134 is withdrawn completely out of
the lumen of the drive shaft 136 prior to during the rotation and
translational motions of the drive shaft 136 for abrading the
lesion 40. In other implementations, the guidewire 134 is withdrawn
only partially. That is, in some implementations a portion of the
guidewire 134 remains within the lumen of the drive shaft 136
during rotation of the drive shaft 136, but remains only in a
proximal portion that is not subject to the significant orbital
path in the area of the one or more abrasive elements 138 (e.g.,
remains within the portion of the drive shaft 136 that remains in
the sheath 132).
[0084] To perform the atherectomy procedure, the drive shaft 136 is
rotated at a high rate of rotation (e.g., 20,000-160,000 rpm) such
that the eccentric one or more abrasive elements 138 revolve in an
orbital path about an axis of rotation and thereby contacts and
removes portions of the lesion 40.
[0085] Still referring to FIGS. 11-13, the rotational atherectomy
system 100 is depicted during the high-speed rotation of the drive
shaft 136. The centrifugal force acting on the eccentrically
weighted one or more abrasive elements 138 causes the one or more
abrasive elements 138 to orbit in an orbital path around the axis
of rotation 139. In some implementations, the orbital path can be
somewhat similar to the orbital motion of a "jump rope." As shown,
some portions of the drive shaft 136 (e.g., a portion that is just
distal of the sheath 132 and another portion that is distal of the
distal stability element 140) can remain in general alignment with
the axis of rotation 139, but the particular portion of the drive
shaft 136 adjacent to the one or more abrasive elements 138 is not
aligned with the axis of rotation 139 (and instead orbits around
the axis 139). As such, in some implementations, the axis of
rotation 139 may be aligned with the longitudinal axis of a
proximal part of the drive shaft 136 (e.g., a part within the
distal end of the sheath 132) and with the longitudinal axis of the
distal extension portion 142 of the drive shaft 136.
[0086] In some implementations, as the one or more abrasive
elements 138 rotates, the clinician operator slowly advances the
carriage assembly distally (and, optionally, reciprocates both
distally and proximally) in a longitudinal translation direction so
that the abrasive surface of the one or more abrasive elements 138
scrapes against additional portions of the occluding lesion 40 to
reduce the size of the occlusion, and to thereby improve the blood
flow through the graft 32. This combination of rotational and
translational motion of the one or more abrasive elements 138 is
depicted by the sequence of FIGS. 11-13.
[0087] In some embodiments, the sheath 132 may define one or more
lumens (e.g., the same lumen as, or another lumen than, the lumen
in which the drive shaft 136 is located) that can be used for
aspiration (e.g., of abraded particles of the lesion 40). In some
cases, such lumens can be additionally or alternatively used to
deliver perfusion and/or therapeutic substances to the location of
the lesion 40, or to prevent backflow of blood from graft 32 into
sheath 132.
[0088] Referring to FIG. 14, a distal end portion of the drive
shaft 136 is shown in a longitudinal cross-sectional view. The
distal end portion of the drive shaft 136 includes the one or more
abrasive elements 138 that are eccentrically-fixed to the drive
shaft 136, the distal stability element 140 with an abrasive outer
surface, and the distal drive shaft extension portion 142.
[0089] In the depicted embodiment, the one or more abrasive
elements 138 includes a total of five discrete abrasive elements
that are spaced apart from each other. In some embodiments, one,
two, three, four, five, six, seven, eight, nine, ten, eleven,
twelve, thirteen, fourteen, fifteen, or more than fifteen discrete
abrasive elements are included as the one or more abrasive elements
138. Each of the five discrete abrasive elements can include the
abrasive media coating.
[0090] In the depicted embodiment, the two outermost abrasive
elements of the abrasive elements 138 are smaller in maximum
diameter than the three inner abrasive elements of the abrasive
elements 138. In some embodiments, all of the abrasive elements are
the same size. In particular embodiments, three or more different
sizes of abrasive elements 138 are included. Any and all such
possible arrangements of sizes of abrasive elements 138 are
envisioned and within the scope of this disclosure.
[0091] The one or more abrasive elements 138 can be made to any
suitable size. For clarity, the size of the one or more abrasive
elements 138 will refer herein to the maximum outer diameter of
individual abrasive elements of the one or more abrasive elements
138. In some embodiments, the one or more abrasive elements 138 are
about 2 mm in size (maximum outer diameter). In some embodiments,
the size of the one or more abrasive elements 138 is in a range of
about 1.5 mm to about 2.5 mm, or about 1.0 mm to about 3.0 mm, or
about 0.5 mm to about 4.0 mm, without limitation. Again, in a
single embodiment, one or more of the abrasive elements 138 can
have a different size in comparison to the other abrasive elements
138. In some embodiments, the two outermost abrasive elements are
about 1.5 mm in diameter and the inner abrasive elements are about
2.0 mm in diameter.
[0092] In the depicted embodiment, the one or more abrasive
elements 138, individually, are oblong in shape. A variety of
different shapes can be used for the one or more abrasive elements
138. For example, in some embodiments the one or more abrasive
elements 138 are individually shaped as spheres, discs, rods,
cylinders, polyhedrons, cubes, prisms, and the like. In some
embodiments, such as the depicted embodiment, all of the one or
more abrasive elements 138 are the same shape. In particular
embodiments, one or more of the abrasive elements 138 has a
different shape than one or more of the other abrasive elements
138. That is, two, three, or more differing shapes of individual
abrasive elements 138 can be combined on the same drive shaft
136.
[0093] In the depicted embodiment, adjacent abrasive elements of
the one or more abrasive elements 138 are spaced apart from each
other. For example, in the depicted embodiment the two distal-most
individual abrasive elements are spaced apart from each other by a
distance `X`. In some embodiments, the spacing between adjacent
abrasive elements is consistent between all of the one or more
abrasive elements 138. Alternatively, in some embodiments the
spacing between some adjacent pairs of abrasive elements differs
from the spacing between other adjacent pairs of abrasive
elements.
[0094] In some embodiments, the spacing distance X in ratio to the
maximum diameter of the abrasive elements 138 is about 1:1. That
is, the spacing distance X is about equal to the maximum diameter.
The spacing distance X can be selected to provide a desired degree
of flexibility of the portion of the drive shaft 136 to which the
one or more abrasive elements 138 are attached. In some
embodiments, the ratio is about 1.5:1 (i.e., X is about 1.5 times
longer than the maximum diameter). In some embodiments, the ratio
is in a range of about 0.2:1 to about 0.4:1, or about 0.4:1 to
about 0.6:1, or about 0.6:1 to about 0.8:1, or about 0.8:1 to about
1:1, or about 1:1 to about 1.2:1, or about 1.2:1 to about 1.4:1, or
about 1.4:1 to about 1.6:1, or about 1.6:1 to about 1.8:1, or about
1.8:1 to about 2.0:1, or about 2.0:1 to about 2.2:1, or about 2.2:1
to about 2.4:1, or about 2.4:1 to about 3.0:1, or about 3.0:1 to
about 4.0:1, and anywhere between or beyond those ranges.
[0095] In the depicted embodiment, the center of mass of each one
of the one or more abrasive elements 138 is offset from the
longitudinal axis of the drive shaft 136 along a same radial angle.
Said another way, the centers of mass of all of the one or more
abrasive elements 138 are coplanar with the longitudinal axis of
the drive shaft 136. If the size of each of the one or more
abrasive elements 138 is equal, the centers of mass of the one or
more abrasive elements 138 would be collinear on a line that is
parallel to the longitudinal axis of the drive shaft 136.
[0096] Referring to FIG. 15, according to some embodiments of the
rotational atherectomy devices provided herein, one or more
abrasive elements 144 are arranged at differing radial angles in
relation to the drive shaft 136. In such a case, a path defined by
the centers of mass of the one or more abrasive elements 144
spirals along the drive shaft 136. In some cases (e.g., when the
diameters of the one or more abrasive elements 144 are equal and
the adjacent abrasive elements are all equally spaced), the centers
of mass of the one or more abrasive elements 144 define a helical
path along/around the drive shaft 136. It has been found that such
arrangements can provide a desirably-shaped orbital rotation of the
one or more abrasive elements 144.
[0097] It should be understood that any of the structural features
described in the context of one embodiment of the rotational
atherectomy devices provided herein can be combined with any of the
structural features described in the context of one or more other
embodiments of the rotational atherectomy devices provided herein.
For example, the size and/or shape features of the one or more
abrasive elements 138 can be incorporated in any desired
combination with the spiral arrangement of the one or more abrasive
elements 144.
[0098] Referring also to FIGS. 16-20, the differing radial angles
of the individual abrasive elements 144a, 144b, 144c, 144d, and
144e can be further visualized. To avoid confusion, each figure of
FIGS. 17-21 illustrates only the closest one of the individual
abrasive elements 144a, 144b, 144c, 144d, and 144e (i.e., closest
in terms of the corresponding cutting-plane as shown in FIG. 16).
For example, in FIG. 17, abrasive element 144b is shown, but
abrasive element 144a is not shown (so that the radial orientation
of the abrasive element 144b is clearly depicted).
[0099] It can be seen in FIGS. 16-20 that the centers of mass of
abrasive elements 144a, 144b, 144c, 144d, and 144e are at differing
radial angles in relation to the drive shaft 136. Hence, it can be
said that the abrasive elements 144a, 144b, 144c, 144d, and 144e
are disposed at differing radial angles in relation to the drive
shaft 136.
[0100] In the depicted embodiment, the radial angles of the
abrasive elements 144a, 144b, 144c, 144d, and 144e differ from each
other by a consistent 37.5 degrees (approximately) in comparison to
the adjacent abrasive element(s). For example, the center of mass
of abrasive element 144b is disposed at a radial angle B that is
about 37.5 degrees different than the angle at which the center of
mass of abrasive element 144a is disposed, and about 37.5 degrees
different than the angle C at which the center of mass of abrasive
element 144c is disposed. Similarly, the center of mass of abrasive
element 144c is disposed at a radial angle C that is about 37.5
degrees different than the angle B at which the center of mass of
abrasive element 144b is disposed, and about 37.5 degrees different
than the angle D at which the center of mass of abrasive element
144d is disposed. The same type of relative relationships can be
said about abrasive element 144d.
[0101] While the depicted embodiment has a relative radial offset
of 37.5 degrees (approximately) in comparison to the adjacent
abrasive element(s), a variety of other relative radial offsets are
envisioned. For example, in some embodiments the relative radial
offsets of the adjacent abrasive elements is in a range of about 0
degrees to about 5 degrees, or about 5 degrees to about 10 degrees,
or about 10 degrees to about 15 degrees, or about 15 degrees to
about 20 degrees, or about 20 degrees to about 25 degrees, or about
25 degrees to about 30 degrees, or about 30 degrees to about 35
degrees, or about 10 degrees to about 30 degrees, or about 20
degrees to about 40 degrees, or about 20 degrees to about 50
degrees.
[0102] While in the depicted embodiment, the relative radial
offsets of the abrasive elements 144a, 144b, 144c, 144d, and 144e
in comparison to the adjacent abrasive element(s) are consistent,
in some embodiments some abrasive elements are radially offset to a
greater or lesser extent than others. For example, while angles B,
C, D, and E are all multiples of 37.5 degrees, in some embodiments
one or more of the angles B, C, D, and/or E is not a multiple of
the same angle as the others.
[0103] The direction of the spiral defined by the centers of mass
of the abrasive elements 144a, 144b, 144c, 144d, and 144e can be in
either direction around the drive shaft 136, and in either the same
direction as the wind of the filars or in the opposing direction as
the wind of the filars.
[0104] A number of embodiments of the invention have been
described. Nevertheless, it will be understood that various
modifications may be made without departing from the spirit and
scope of the invention. For example, design features of the
embodiments described herein can be combined with other design
features of other embodiments described herein. Accordingly, other
embodiments are within the scope of the following claims.
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