U.S. patent application number 17/576881 was filed with the patent office on 2022-05-05 for laser slotted grabbing device.
This patent application is currently assigned to STRYKER CORPORATION. The applicant listed for this patent is STRYKER CORPORATION. Invention is credited to E. Skott Greenhalgh, Michael P. Wallace.
Application Number | 20220133348 17/576881 |
Document ID | / |
Family ID | |
Filed Date | 2022-05-05 |
United States Patent
Application |
20220133348 |
Kind Code |
A1 |
Wallace; Michael P. ; et
al. |
May 5, 2022 |
LASER SLOTTED GRABBING DEVICE
Abstract
Mechanical atherectomy and/or thrombectomy devices configured to
remove obstructions (e.g., plaque material) of different
consistencies and/or sizes from blood vessels. The devices may
include a tractor comprising a flexible tube of material that
inverts as it rolls over itself while being drawn into the open
distal end of a catheter in a conveyor-like motion. The flexible
tube can include features that facilitate engagement with the
obstruction, enhance smooth tractor motion and/or promote movement
control of the device within the blood vessel.
Inventors: |
Wallace; Michael P.;
(Pleasanton, CA) ; Greenhalgh; E. Skott;
(Gladwyne, PA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
STRYKER CORPORATION |
Fremont |
CA |
US |
|
|
Assignee: |
STRYKER CORPORATION
Fremont
CA
|
Appl. No.: |
17/576881 |
Filed: |
January 14, 2022 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
16566393 |
Sep 10, 2019 |
11253291 |
|
|
17576881 |
|
|
|
|
62729311 |
Sep 10, 2018 |
|
|
|
International
Class: |
A61B 17/3207 20060101
A61B017/3207; A61B 17/22 20060101 A61B017/22 |
Claims
1. An atherectomy device for removing a plaque material from a
blood vessel, the device comprising: a catheter having a distal
edge defining an opening that provides access to a lumen within the
catheter; and a tractor comprising a flexible, laser-cut metallic
tube that at least partially covers and extends along an outer
surface of the catheter and inverts over the catheter distal edge,
such that a first end of the flexible, laser-cut metallic tube
extends through the opening into the lumen of the catheter, wherein
the flexible, laser-cut metallic tube comprises a plurality of
engagement features cut into an outer surface of the flexible,
laser-cut metallic tube and through the flexible, laser-cut
metallic tube to form a plurality of cutting edges and wherein the
flexible, laser-cut metallic tube is configured so that pulling the
first end of the flexible, laser-cut metallic tube proximally
through the catheter lumen causes the flexible, laser-cut metallic
tube to roll and invert over the catheter distal edge, thereby
exposing the cutting edges distally as the flexible tube rolls into
the catheter lumen.
2. The device of claim 1, wherein the cutting edges are aligned
along a length of the flexible, laser-cut metallic tube.
3. The device of claim 1, wherein the cutting edges are configured
scrape the plaque material on a wall of the blood vessel when the
first end of the flexible, laser-cut metallic tube is pulled
proximally through the catheter lumen.
4. The device of claim 1, wherein the cutting edges are configured
to gouge the plaque material on a wall of the blood vessel when the
first end of the flexible, laser-cut metallic tube is pulled
proximally through the catheter lumen.
5. The device of claim 1, wherein the plurality of engagement
features are arranged into a series of circumferential bands
extending along a length of the flexible, laser-cut metallic tube,
such that the respective bands of engagement features pass
sequentially over the distal edge of the catheter as the flexible
tube rolls into the catheter lumen.
6. The device of claim 5, further comprising a series of links,
wherein each link of the series extends between respective adjacent
bands of engagement features.
7. The device of claim 6, wherein the links are arranged in a
circumferentially offset pattern along the length of the flexible,
laser-cut metallic tube.
8. The device of claim 6, wherein the links are arranged in a
circumferentially aligned pattern along the length of the flexible,
laser-cut metallic tube.
9. The device of claim 1, wherein the engagement features comprise
a first set of features defined by having a first aspect ratio, and
a second set of features defined by having a second aspect ratio
that is different than the first aspect ratio.
10. The device of claim 1, wherein the engagement features comprise
a first set of features defined by having sharp engagement
surfaces, and a second set of features defined by having curved
engagement surfaces.
11. The device of claim 1, wherein engagement features of a first
set of the engagement features have a first shape configured for
shoveling the plaque material, and engagement features of a second
set of the engagement features have a second shape configured for
gouging the plaque material.
12. The device of claim 1, wherein engagement features of a first
set of the engagement features have a first shape configured for
cutting the plaque material, and engagement features of a second
set of the engagement features have a second shape configured for
gouging the plaque material.
13. The device of claim 1, wherein engagement features of a first
set of the engagement features have a first shape configured for
cutting the plaque material, engagement features of a second set of
the engagement features have a second shape configured for gouging
the plaque material, and engagement features of a third set of the
engagement features have a third shape configured for shoveling the
plaque material.
14. An atherectomy device for removing a plaque material from a
blood vessel, comprising: a catheter having a distal edge that
defines an opening that provides access to an internal lumen; and a
flexible tube that covers at least a portion of the distal edge and
enters the internal lumen of the catheter, the flexible tube
comprising a series of adjacent band regions extending radially
around the flexible tube each band region comprising a plurality of
metallic, laser-cut engagement features that are configured to
engage with the plaque material, wherein the band regions are
offset from each other along a length of the flexible tube so that
the engagement features of adjacent band regions are offset from
one another, wherein when the device is activated, each of the
engagement features passes over the distal edge such that the
engagement features protrude from the distal edge to engage with
and direct the plaque material toward the internal lumen.
15. The device of claim 14, wherein the engagement features of
adjacent band regions are offset from one another long the length
of the flexible tube.
16. The device of claim 14, wherein each band region has three to
five engagement features per centimeter length of the band
region.
17. The device of claim 14, wherein the flexible tube has two to
three bands per centimeter length of the flexible tube.
18. The device of claim 14, wherein the flexible tube comprises a
plurality of band connectors that connect the adjacent band
regions.
19. The device of claim 14, wherein the series of band regions form
a continuous spiral around the flexible tube.
20. The device of claim 18, wherein the band connectors are in an
offset arrangement with respect to each other within the flexible
tube.
21. The device of claim 18, wherein the band connectors are in an
aligned arrangement with respect to each other within the flexible
tube.
22. The device of claim 14, wherein a second portion of the band
regions have an aligned arrangement where the engagement features
of adjacent band regions are aligned with one another.
23. The device of claim 14, wherein the flexible tube comprises a
plurality of fastening elements that couple the flexible tube to a
puller that provides a pulling force to activate the device.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This patent application is a continuation of U.S. patent
application Ser. No. 16/566,393, filed Sep. 10, 2019, which claims
priority to U.S. provisional patent application No. 62/729,311,
filed on Sep. 10, 2018, titled "Laser Slotted Grabbing Device." The
foregoing applications are hereby incorporated by reference into
the present application in its entirety.
INCORPORATION BY REFERENCE
[0002] All publications and patent applications mentioned in this
specification are herein incorporated by reference in their
entirety to the same extent as if each individual publication or
patent application was specifically and individually indicated to
be incorporated by reference.
FIELD
[0003] The devices and methods described herein relate to
mechanical removal of objects within a body. In particular,
described herein are thrombectomy and atherectomy devices and
methods.
BACKGROUND
[0004] Maintenance of blood fluidity within the vascular system is
an important physiological process. Normally, blood flows freely
through a blood vessel to carry blood with oxygen and nutrients to
different tissues of the body. If the blood vessel is injured, the
body's normal response is to form a clot that serves to limit blood
hemorrhaging. This normal response is referred to as hemostasis. A
thrombus is a blood clot that results when hemostasis is
excessively activated in the absence of bleeding. A thrombus can
stem from any of a number of causes, such as trauma, various
conditions that cause abnormal blood flow or blood coagulation
conditions. A thrombus in a large blood vessel may decrease blood
flow through that vessel. In a small blood vessel, blood flow may
be completely cut off, resulting in death of tissue supplied by
that vessel.
[0005] A thrombectomy is a procedure for removing a blot clot from
a vessel to restore blood flow within the vessel. Catheter-based
thrombectomy techniques involve inserting a catheter through the
blood vessel in order to reach the clot and remove it from the
vessel. As with many medical procedures, it is desirable to reduce
the occurrence of damage to the tissues and cells during a
thrombectomy. For example, minimally invasive techniques may
include limiting the size of any incisions associated with the
procedure. For a thrombectomy, a minimally invasive procedure may
involve inserting a smaller catheter within the blood vessel to
lessen the amount of damage to the vessel and surrounding tissues.
Although catheter-based thrombectomy technologies may incorporate
minimally invasive techniques, challenges still remain. For
example, the catheter device should be able to effectively and
efficiently remove the blood clot from a blood vessel while
maintaining a small profile in order to reduce damage to tissues.
Therefore, there is a need for space efficient and effective
grabbing devices for catheter-based procedures.
SUMMARY OF THE DISCLOSURE
[0006] The present disclosure relates to grabbing devices suitable
for use in removing an obstruction from a blood vessel. The
grabbing devices can include a catheter having an inner cavity and
a flexible scraping tube (e.g., tractor) that is configured to
engage with an obstruction within a blood vessel and to direct the
obstruction toward the inner cavity of the catheter. The tractor
may be reciprocated. Described herein are various configurations of
the catheter, tractor and other features of the grabbing device
that can facilitate the capture and removal of an obstruction from
a blood vessel.
[0007] In some embodiments, the tractor comprises a flexible tube
that includes a number of engagement features that are configured
to engage with the obstruction. The engagement features are
configured to scrape against, so as to remove (e.g., by cutting,
taring, chipping, pulling, etc.) plaque from the vessel wall(s).
The engagement features may be arranged on a series of bands that
are held together by a number of band connectors. Features of the
tractor, such as the material, wall thickness, number and size of
bands, engagement feature shapes and sizes, and number and
placement of band connectors can be configured to emphasize or
optimize various functions of the grabbing device. The operation of
the grabbing device may be evaluated based on a number of
performance parameters, such as rolling force, grabbing strength,
maneuverability (e.g., within the blood vessel), durability and
radio-opacity.
[0008] As will be described in greater detail below, the tractor is
generally configured to roll from outside of the catheter into the
inner lumen of the catheter, everting over the distal end of the
catheter so that the engagement features extending from the tractor
(on all sides or just a sub-region, e.g., one side or region of the
tractor) may scrape against and/or remove plaque material. The
tractor may be continuously rolled (e.g., pulled into the catheter
or out of the catheter, through preferably into) and/or may be
reciprocated, e.g., rolled out of, then into, the catheter. In some
variations the tractor is moved in a ratcheting manner, so that it
is reciprocated, but with a net movement into the catheter, to
drawn in material removed by the engagement features. For example,
the tractor may be pulled or driven into the catheter distal end in
a first distance, then withdrawn out of the catheter distal end in
a second, opposite, direction, a second distance that is slightly
less than the first distance, resulting in a net overall movement
into the catheter.
[0009] By way of example and without limitation, in one exemplary
embodiment of the disclosed inventions, an atherectomy device for
removing a plaque material from a blood vessel includes a catheter
having a distal edge defining an opening that provides access to a
lumen within the catheter, and a tractor comprising a flexible tube
that at least partially covers and extends along an outer surface
of the catheter and inverts over the catheter distal edge, such
that a first end of the flexible tube extends through the opening
into the lumen of the catheter, wherein the flexible tube comprises
a plurality of engagement features cut at an acute angle into an
outer surface of the flexible tube to form a plurality of acute
cutting edges, and wherein the flexible tube is configured so that
pulling the first end of the flexible tube proximally through the
catheter lumen causes the flexible tube to roll and invert over the
catheter distal edge, thereby exposing the acute cutting edges
distally as the flexible tube rolls into the catheter lumen.
[0010] The acute cutting edges may be circumferentially spaced
apart or aligned, or some of each, along a length of the flexible
tube, and may be configured to scrape or gouge the plaque material
on a wall of the blood vessel when the first end of the flexible
tube is pulled proximally through the catheter lumen. By way of
example, the engagement features may be arranged into a series of
circumferential bands spaced apart longitudinally along a length of
the flexible tube, such that the respective bands of engagement
features pass sequentially over the distal edge of the catheter as
the flexible tube rolls into the catheter lumen. The atherectomy
device may further include respective links that extend between
adjacent bands of engagement features, wherein the links may be
arranged in a circumferentially offset pattern, a circumferentially
aligned pattern, or some of each, along the length of the flexible
tube.
[0011] By way of further examples, and without limitation, the
engagement features may include a first set of features defined by
having a first aspect ratio, and a second set of features defined
by having a second aspect ratio that is different than the first
aspect ratio. For example, the engagement features may include a
first set of features defined by having sharp engagement surfaces,
and a second set of features defined by having curved engagement
surfaces. Additionally, or alternatively, engagement features of a
first set of the engagement features may have a first shape
configured for shoveling the plaque material, and engagement
features of a second set of the engagement features may have a
second shape configured for gouging the plaque material. For
example, in one embodiment, engagement features of a first set of
the engagement features have a first shape configured for cutting
the plaque material, and engagement features of a second set of the
engagement features have a second shape configured for gouging the
plaque material. In another embodiment, engagement features of a
first set of the engagement features have a first shape configured
for cutting the plaque material, engagement features of a second
set of the engagement features have a second shape configured for
gouging the plaque material, and engagement features of a third set
of the engagement features have a third shape configured for
shoveling the plaque material.
[0012] In another exemplary embodiment of the disclosed inventions,
an atherectomy device for removing a plaque material from a blood
vessel includes a catheter having distal end portion configured for
entering the blood vessel, and a distal edge that defines an
opening that provides access to an internal lumen of the catheter,
and an activatable tractor comprising a flexible tube that at least
partially covers and extends along an outer surface of the distal
end portion of the catheter and inverts over the catheter distal
edge, such that an end portion of the flexible tube extends through
the opening into the internal lumen of the catheter, the flexible
tube having an outer surface comprising engagement features having
a plurality of different shapes, wherein when the tractor is
activated, the flexible tube moves around the catheter distal edge
such that the engagement features protrude from the distal edge to
engage with and direct the plaque material toward the internal
lumen. Without limitation, the tractor may be configured such that,
when the tractor is activated, the flexible tube moves around the
catheter distal edge in a reciprocating motion.
[0013] The engagement features may include a first set of
protruding features defined by having a first aspect ratio and a
second set of protruding features defined by having a second aspect
ratio different than the first aspect ratio. For example, the
engagement features may include a first set of protruding features
defined by having sharp engagement surfaces and a second set of
protruding features defined by having curved engagement
surfaces.
[0014] Additionally, or alternatively, engagement features of a
first set of the engagement features may have a first shape
configured for shoveling the plaque material, and engagement
features of a second set of the engagement features have a second
shape configured for gouging the plaque material. For example, a
first set of the engagement features may have a first shape
configured for cutting the plaque material, and a second set of the
engagement features may have a second shape configured for gouging
the plaque material. In one embodiment, engagement features of a
first set of the engagement features have a first shape configured
for cutting the plaque material, engagement features of a second
set of the engagement features have a second shape configured for
gouging the plaque material, and engagement features of a third set
of the engagement features have a third shape configured for
shoveling the plaque material.
[0015] In yet another exemplary embodiment of the disclosed
inventions, an atherectomy device for removing a plaque material
from a blood vessel includes a catheter having a distal edge that
defines an opening that provides access to an internal lumen; and
an activatable tractor comprising a flexible tube that covers at
least a portion of the distal edge and enters the catheter lumen,
the flexible tube having an outer surface comprising a series of
longitudinally spaced apart circumferential bands of engagement
features configured to engage with the plaque material, wherein the
engagement features of at least two adjacent bands are
circumferentially offset from one another, and wherein, when the
tractor is activated, the bands pass sequentially over the catheter
distal edge such that the engagement features protrude from the
distal edge to engage and direct the plaque material toward the
catheter lumen.
[0016] Without limitation, each band may have three to five
engagement features per centimeter length of the band, and the
flexible tube may have two to three bands per centimeter length of
the flexible tube. Links may be provided between respective
adjacent bands of engagement features, wherein the links may be
arranged in a circumferentially offset pattern, a circumferentially
aligned pattern, or some of each pattern along the length of the
flexible tube. The flexible tube may be provided with fastening
elements that couple the flexible tube to a puller disposed in the
catheter lumen.
[0017] Other and further aspects and features of the disclosed
inventions are described herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The novel features of the invention are set forth with
particularity in the claims that follow. A better understanding of
the features and advantages of the present invention will be
obtained by reference to the following detailed description that
sets forth illustrative embodiments, in which the principles of the
invention are utilized, and the accompanying drawings of which:
[0019] FIGS. 1A and 1B show a side view and a cross section view,
respectively, of a catheter.
[0020] FIG. 2 shows a side view of a catheter with a tractor having
grabbing surfaces.
[0021] FIGS. 3A and 3B show perspective views of tractors
indicating various tractor features.
[0022] FIGS. 4A-4I show plan views of various cutting patterns for
forming various engagement features of a tractor.
[0023] FIGS. 5A and 5B show different laser cutting operations for
forming engagement feature of a tractor.
[0024] FIGS. 6A and 6B illustrate one method of forming an
engagement feature of a tractor by cutting (e.g., in this example,
using a laser) at an angle relative to the surface of the tractor,
to form an acute cutting edge on one portion of the engagement
feature. FIG. 6A shows a view of the overall flexible tube (e.g., a
metal, such as Nitinol, or polymeric tube) while FIG. 6B shows an
enlarged region.
[0025] FIG. 7 shows a cross section view of a tractor having
engagement features with acute cutting edges (not necessarily to
scale).
[0026] FIGS. 8A and 8B show plan views of unrolled tractors having
different connector arrangements.
[0027] FIG. 9 shows a perspective view of a tractor that includes a
stretched portion.
[0028] FIG. 10 shows a plan view of a cut pattern for a tractor
with multiple openings and a network of struts.
[0029] FIGS. 11A-11B show a plan views of one variation of a strut
network having openings and struts that may form the tractor
portion of a device (e.g., an atherectomy device) as described
herein. FIG. 11B shows an enlarged view of section A of FIG.
11A.
[0030] FIG. 12 shows a plan views of one variation of a strut
network having openings and struts that may form the tractor
portion of a device (e.g., an atherectomy device) as described
herein.
[0031] FIGS. 13A-13B show a plan views of a variation of a strut
network having openings and struts that may form the tractor
portion of a device (e.g., an atherectomy device) as described
herein. FIG. 13B shows an enlarged view of section A of FIG. 13A;
the dimensions shown in FIGS. 13A-13B are intended only as one
example, actual dimensions may be different.
[0032] FIGS. 14A-14B show a plan views of a variation of a strut
network having openings and struts that may form the tractor
portion of a device (e.g., an atherectomy device) as described
herein. FIGS. 14A-14B shows an enlarged view of section B of FIG.
14A; the dimensions shown in FIG. 14B are intended only as one
example, actual dimensions may be different.
[0033] FIGS. 15A-15B show a plan views of a variation of a strut
network having openings and struts that may form the tractor
portion of a device (e.g., an atherectomy device) as described
herein. FIG. 15B shows an enlarged view of section B of FIG. 15A;
the dimensions shown in FIGS. 15A-15B are intended only as one
example, actual dimensions may be different.
[0034] FIGS. 16A-16B show a plan views of a variation of a strut
network having openings and struts that may form the tractor
portion of a device (e.g., an atherectomy device) as described
herein. FIG. 16B shows an enlarged view of section B of FIG. 16A;
the dimensions shown in FIGS. 16A-16B are intended only as one
example, actual dimensions may be different.
[0035] FIGS. 17A-17B show a plan views of a variation of a strut
network having openings and struts that may form the tractor
portion of a device (e.g., an atherectomy device) as described
herein. FIG. 17B shows an enlarged view of section B of FIG. 17A;
the dimensions shown in FIGS. 17A-17B are intended only as one
example, actual dimensions may be different.
[0036] FIGS. 18A-18B show a plan views of a variation of a strut
network having openings and struts that may form the tractor
portion of a device (e.g., an atherectomy device) as described
herein. FIG. 18B shows an enlarged view of section B of FIG. 18A;
the dimensions shown in FIGS. 18A-18B are intended only as one
example, actual dimensions may be different.
[0037] FIGS. 19A-19B show a plan views of a variation of a strut
network having openings and struts that may form the tractor
portion of a device (e.g., an atherectomy device) as described
herein. FIG. 19B shows an enlarged view of section B of FIG. 19A;
the dimensions shown in FIGS. 19A-19B are intended only as one
example, actual dimensions may be different.
[0038] FIGS. 20A-20B show a plan views of a variation of a strut
network having openings and struts that may form the tractor
portion of a device (e.g., an atherectomy device) as described
herein. FIG. 20B shows an enlarged view of section B of FIG. 20A;
the dimensions shown in FIGS. 20A-20B are intended only as one
example, actual dimensions may be different.
[0039] FIGS. 21A-21B show a plan views of a variation of a strut
network having openings and struts that may form the tractor
portion of a device (e.g., an atherectomy device) as described
herein. FIG. 21B shows an enlarged view of section B of FIG. 21A;
the dimensions shown in FIGS. 21A-21B are intended only as one
example, actual dimensions may be different.
[0040] FIGS. 22A-22B show a plan views of a variation of a strut
network having openings and struts that may form the tractor
portion of a device (e.g., an atherectomy device) as described
herein. FIG. 22B shows an enlarged view of section B of FIG. 22A;
the dimensions shown in FIGS. 22A-22B are intended only as one
example, actual dimensions may be different.
[0041] FIGS. 23A-23B show a plan views of a variation of a strut
network having openings and struts that may form the tractor
portion of a device (e.g., an atherectomy device) as described
herein. FIG. 23B shows an enlarged view of section B of FIG. 23A;
the dimensions shown in FIGS. 23A-23B are intended only as one
example, actual dimensions may be different.
[0042] FIGS. 24A-24B show a plan views of a variation of a strut
network having openings and struts that may form the tractor
portion of a device (e.g., an atherectomy device) as described
herein. FIG. 24B shows an enlarged view of section B of FIG. 24A;
the dimensions shown in FIGS. 24A-24B are intended only as one
example, actual dimensions may be different.
[0043] FIG. 25 shows a plan views of another variation of a strut
network having openings and struts that may form the tractor
portion of a device (e.g., an atherectomy device) as described
herein.
DETAILED DESCRIPTION
[0044] Described herein are catheter-based grabbing devices for
removing obstructions from a blood vessel. The devices may be
suitable for use in a thrombectomy and/or an atherectomy (e.g., a
plaque removal). A thrombectomy is a procedure for removing a blood
clot, also referred to as a thrombus, from a blood vessels. A blood
clot can contain a combination of blood components such as
platelets and red blood cells. An atherectomy is a procedure for
removing an atheroma, also referred to as an atheromatous plaque
(or simply plaque), from a blood vessel. An atheroma can contain an
accumulation of degenerative material, which may include macrophage
cells, or debris, containing lipids, calcium and a variable amount
of fibrous connective tissue.
[0045] The properties of blood vessel obstructions can vary
greatly. For example, some blood clots can have a soft jelly-like
consistency. More mature blood clots may have a firmer consistency,
similar to that of gummy bear candy. An atheroma may have a more
firm consistency, such as similar to that of wax, lipstick or even
as hard as hard candy. Some obstructions can be very large,
especially in peripheral regions such as the legs. In some cases,
the obstructions can be as long as tens of centimeters (e.g., 30
cm) in length. Other obstructions can be much smaller but may still
obstruct the flow of blood if they reside within smaller blood
vessels.
[0046] The grabbing devices described herein can be configured to
capture and remove blood vessel obstructions and/or plaques having
a wide range of sizes and consistencies. The grabbing devices may
include a tractor comprising a flexible tube of material that
inverts as it rolls over itself while being drawn into a catheter
in a conveyor-like motion. The flexible tube can have engagement
feature that are configured to protrude from a distal end of the
catheter in a rotating motion. The protruding engagement features
can engage with the obstruction and pull at least a portion of the
obstruction into the catheter. In some cases, the grabbing devices
are configured to capture the obstruction in whole. In some cases,
the grabbing devices are configured to break up the obstruction to
more manageably-sized pieces before or during the capturing
process. The shapes, sizes and rigidity of the engagement features
can be selected so as to increase the capture efficiency of the
grabbing device, which can be based at least in part on properties
of the obstruction.
[0047] The grabbing device (e.g., atherectomy device) can include a
number of grabbing surfaces, which are supported by a support
structure. In some embodiments, the support structure includes a
catheter. FIGS. 1A and 1B show a side view and a cross section
view, respectively, of a catheter 101 in accordance with some
embodiments. At least a portion of the catheter may be a tube
having an outer surface 109, inner surface, and an edge 105 (also
referred to as a rim) that at least partially defines an opening.
The opening can have any shape and size. For example, the opening
can have a round, oval or elliptical shape. The length and diameter
(outer diameter and/or inner diameter) of the catheter can vary,
depending on application requirement. For example, a catheter
having a smaller outer diameter (catheter OD 111) may be suitable
for inserting with smaller blood vessels, a catheter having a
larger outer diameter may be suitable for inserting with larger
blood vessels. The opening of the catheter can provide access to an
internal cavity within the catheter.
[0048] The grabbing device 100 can include a flexible material
(e.g., tractor tube), which can be configured to wrap around at
least a portion of the outer surface, and at least partially enter
the internal cavity of the catheter. In some cases, the flexible
material is configured to form a tube shape. FIG. 2 shows a side
view of a catheter 101 with a flexible tube 121, which can be part
of a tractor configured to pull an obstruction. The flexible tube
can have an inner diameter (flexible tube ID) in associated with
the outer diameter of the catheter. In some cases, the flexible
tube directly contacts the outer surface of the catheter. In some
cases, one or more intermediate layers (e.g., sleeves, not shown)
is/are between the flexible tube and the outer surface of the
catheter. In some cases, the outer surface of the catheter and/or
an inner surface of the flexible tube has a coating (e.g., low
friction coating). The coating may include a hydrophilic coating or
a lubricant. In some embodiments, the outer surface of the catheter
and/or an inner surface of the flexible tube has a smoothed (e.g.,
polished) surface. For example, a laser polishing process may be
used to smooth portions of the flexible tube.
[0049] The flexible tube may be any appropriate length. For
example, the flexible tube may be between 3 to 100 centimeters (cm)
long (e.g., between 3 and 50 cm, between 3 and 40 cm, between 3 and
30 cm, between 3 and 20 cm, between 10 and 100 cm, between 10 and
50 cm, between 20 and 100 cm, between 20 and 50 cm, etc.).
[0050] The flexible tube can have a first end 127, which can be
operationally coupled with one or more pulling devices to place a
pulling force on the flexible tube. Pulling device (puller 133) can
be a wire, rod, catheter, tube, etc.). The pulling force 135 can
cause the flexible tube to retract into the internal cavity of the
catheter, thereby inverting at least a portion of the flexible
tube. In some cases, the pulling force includes a vacuum force
and/or one or more mechanical pullers. In some embodiments, the
puller(s) includes one or more wires, catheters and/or strings. The
puller(s) may be positioned within the catheter and/or outside of
the catheter. The puller(s) may be operationally coupled with one
or more actuators and/or motors that drive the pulling force. In
some variations a second puller (not shown) may be attached to the
second end 129 to allow the flexible tube to be reciprocated over
(in/out) of the distal end of the catheter. The second puller may
be one or more wires, a tube or sleeve, etc. The amount of force
may vary depending on the application. In some cases, the one or
more actuators and/or motors is configured to apply less than 300
grams (g) of force (e.g., less than 400 g, less than 300 g of
force, less than 200 g of force, less than 100 g of force, less
than 90 g of force, less than 80 g of force, less than 70 g of
force, less than 60 g of force, less than 50 g of force, less than
10 g of force, etc.) to the first end of the flexible tube. The
force required to retract the flexible tube into the catheter
typically refers to the force required to roll the flexible tube
over the distal end of the catheter; an initial deployment force
(e.g., to release the end of the tractor outside of the catheter)
may be greater than the force required to retract the catheter
(e.g., greater than 100 g of force, 200 g of force, 300 g of force,
400 g of force, 500 g of force, 600 g of force, 700 g of force, 800
g of force, 900 g of force, 1000 g of force, 1500 g of force, 2000
g of force, etc.).
[0051] During operation, a pulling force 135 applied to the first
end 127 of the flexible tube can cause the flexible tube to pass
over the distal end edge of the catheter such that grabbing
surfaces extending from the distal end edge of the catheter in a
grabbing direction. When the flexible tube comes in contact with an
obstruction, the grabbing surfaces 123 can engage with and pull the
obstruction toward the internal cavity. In some variations, the
puller may push or push and pull, e.g., when reciprocating the
tractor. Thus, the flexible tube can act as a tractor that
cooperates with the catheter to apply a drawing force on the
obstruction. Once at least a portion of the obstruction is
sufficiently secured by the grabbing device, the grabbing device
can be removed from the blood vessel with the obstruction secured
within the cavity, thereby removing the obstruction from the blood
vessel. Once removed from the blood vessel, in some embodiments the
grabbing device is configured to release the obstruction material
137 from within the internal cavity by reversing the direction of
the tractor (e.g., in the grabbing direction 139). For example, a
pulling force can be applied to the second end of the flexible
tube, thereby causing the flexible tube to roll over the edge of
the catheter in a releasing direction that is opposite the grabbing
direction.
[0052] In some applications, the grabbing device is guided within a
least a portion of the blood vessel using a guide catheter. For
example, the grabbing device can be inserted co-axially through an
internal cavity of the guide catheter. In such cases, the grabbing
device can be configured to track/slide within the guide catheter
with minimal friction. For example, an outer surface of the
flexible tube (e.g., in contact with the inner surface of the guide
catheter) can include one or more low friction coatings (e.g.,
hydrophilic coating and/or lubricant). In some cases, one or more
intermediate layers (e.g., sleeves) is placed between the outer
surface of the flexible tube and the inner surface of the guide
catheter. In some embodiments, the outer surface of the flexible
tube has a smoothed (e.g., polished) surface. Such low friction
features can allow the grabbing device to be moved forward,
backward and/or axially rotated (twisted) with little force.
[0053] The grabbing features of the flexible tube can be configured
to engage with the obstruction in a manner that facilitates capture
of the obstruction within the grabbing device. FIGS. 3A and 3B show
perspective views of different flexible tubes, in accordance with
some embodiments. The grabbing features 306 can include a series of
bands (also referred to as hoops 308 or rows), which are connected
to each other via connectors 310 (also referred to as band
connectors, hoop connectors or row connectors or links). The hoops
can include multiple engagement features that are configured to
engage with the obstruction. FIG. 3B shows a portion of a flexible
tube having seven (7) consecutive hoops per centimeter 312 and
twenty (20) engagement features 306 per hoop perimeter. At least
some of the engagement features within a given hoop can be
configured to project from the distal end of the catheter 301 as
the hoop rolls over the edge 305 of the catheter. The first end
and/or the second end 329 of the flexible tube may include one or
more fastening elements 316 that are configured to facilitate the
coupling of the flexible tube with one or more pull and/or push
connectors (e.g., wires, strings, tubes, etc.). The fastening
elements may correspond to fingers that extend from the flexible
tube (e.g., from one of hoops), and that include one or more
openings configured to accept the pull and/or push
connector(s).
[0054] The flexible tube may be formed of any type of material,
such as fibrous material (e.g., natural and/or synthetic), polymer
material and/or metal material. Metal materials can include metal
alloys and/or pure metal material. In some cases, the type of
material may be chosen based on its rigidity or malleability. The
various engagement features, hoops, hoop connectors and/or
fastening elements can be formed using any process. In some
embodiments, a laser cutting process is used, which may provide
precision cutting of small dimensions. The laser cutting process
may involve directing a laser beam at a sheet or tube of material
(e.g., metal or plastic) to cut a pattern of openings (e.g., holes
and/or slits) within the sheet or tube. The material between the
openings form a network of struts, where at least some of the
struts correspond to the engagement features of the tractor. If the
material is in the form of sheet, the sheet may be rolled into a
tubular form with the ends of the sheet coupled using any technique
(e.g., welding, melting, gluing, etc.).
[0055] FIG. 10 shows a plan view of a cutting pattern for a
flexible tube with multiple openings 1044 and a network of struts
1043. FIGS. 11A-25 show plan views of various strut networks having
openings and struts with different sizes and shapes. The struts can
form a network of structures that perform various functions. For
example, referring to FIG. 11A and inset view of FIG. 11B, the
struts can form hoops 1108, hoop connectors 1110, engagement
features 1106 and fastening elements 1116, 1116'. The openings 1151
and struts can have any shape. The shape of the openings 1151
and/or struts can at least partially dictate how the flexible tube
moves, collapse, compresses, expands, etc. In some embodiments, the
openings have shape corresponding to slits (kerfs), polygons (e.g.,
diamond, triangular, square, rectangular, pentagonal and/or
hexagonal), circles, ovals, ellipses or irregular shapes. The shape
and sizes of the struts corresponding to engagement features can at
least partially dictate how the engagement features interact with
the obstruction (e.g., scooping, gouging, cutting, etc.).
[0056] The sizes and shapes of the engagement features can be
configured to engage with the obstruction in a prescribed manner,
which may depend in part on characteristics of the obstruction. In
some embodiments, an engagement feature has a shape in accordance
with a gouger, poker, needle, dagger, lance, lancet, sickle, point
or spear, which may provide a gouging action. In some embodiments,
an engagement feature has a shape in accordance with a scooper,
scraper, shovel, or spoon, which may provide a scooping or scraping
action. In some embodiments, an engagement feature has a shape in
accordance with a blade, cutter or knife, which may provide a
cutting action (e.g., for breaking up obstructions). Engagement
features that provide a combination of engagement actions (e.g.,
scooping, scraping, gouging and/or cutting) may be effective for
capturing some obstructions.
[0057] According to some embodiments, the engagement features are
formed by cutting a prescribed pattern of openings (e.g., holes
and/or slits) within a sheet or tube. FIGS. 4A-4I show plan views
of various cutting patterns for forming engagement features having
different shapes and sizes, according to some embodiments. FIGS. 4A
and 4C-4I show examples of various zig-zag cutting patterns for
forming engagement features having sharp engagement surfaces. FIG.
4B shows an example of cutting patterns for forming engagement
features having curved engagement surfaces. Sharper engagement
surfaces may provide more of a gouging and/or cutting action, and
curvier engagement features may provide more of a scooping or
shoveling action. The sharpness of an engagement feature may be
depend, in part, on an aspect ratio of a feature cut. Referring to
FIG. 4D, for example, an aspect ratio of an engagement feature can
refer to its width 475 divided by its height 477. Those engagement
features having higher aspect ratios may provide more of a gouging
action compared to engagement features having lower aspect ratios.
FIG. 4C shows an example cutting pattern that provide an engagement
feature having a first portion 471 having a first aspect ratio and
a second portion 473 having a second aspect ratio different (e.g.,
greater) than the first aspect ratio.
[0058] In some cases, the tractor has engagement features with
different shapes and sizes. For example, FIG. 4H shows a cutting
pattern for forming hoop (row) of engagement features having a
first type 481 and a second type 479, wherein the shapes (e.g.,
aspect ratios) of the first and second types of engagement features
are different. A tractor and include any combination of engagement
features having any of a number of different shapes and sizes. For
example, a hoop can include any combination of sharp (e.g., FIGS.
4A and 4C-4I) and curved (e.g., FIG. 4B) engagement features. In
some cases, a tractor includes a first hoop having a first type of
engagement features (e.g., having a first shape and/or size) and a
second hoop having a second type of engagement features (e.g.,
having a second shape and/or size). In some cases, a tractor
includes a first hoop having a first combination of engagement
features having different shapes and sizes, and a second hoop
having a second combination of engagement features. In some
embodiments, the engagement features include supplemental features
483, such as protruding barbs, holes, pores and/or nubs, which can
facilitate engagement with the obstruction. FIG. 4I shows an
example of engagement features having protruding barbs.
[0059] The laser cut path for cutting the various openings within
the tube/sheet of material can be modified to affect the grabbing
properties of the engagement features. FIGS. 5A and 5B show section
views of laser cutting operations according to some embodiments.
FIG. 5B shows a close-up view of FIG. 5A. The laser beam 508 may be
directed at the tube/sheet 510 at a substantially perpendicular
angle with respect to a surface of the tube/sheet. The resulting
strut/engagement feature will have a substantially 90 degree
cutting edge 512. FIGS. 6A and 6B show cross section views of a
laser cutting operation according to another embodiment, where the
laser beam 608 is directed at the tube/sheet 610 at a
non-perpendicular angle 612, 612' (e.g., 5, 10, 20, 30, 40, 45, 50,
60, 70 80, 85, 95, 100, 110, 120, 130, 135, 140, 150, 160, 170 or
175 degrees) with respect to a surface of the tube/sheet. The
resulting struts/engagement features will have correspondingly
non-perpendicular edges. This process can be used to form
engagement features having acute cutting edges, wherein the acute
cutting edges have angles of less than 90 degrees (e.g., 5, 10, 20,
30, 40, 45, 50, 60, 70, 80, 85 or 89 degrees).
[0060] FIG. 7 shows a cross sectional view of a tractor 721 having
engagement features 706 with acute cutting edges 714 as it rotates
(e.g., rolls) around an edge of a catheter (shown in cross-section
716, 716' at the distal end opening 718). When the flexible tube is
installed on the catheter, the acute cutting edges can be aligned
along the longitudinal axis of the catheter. When the tractor is
activated, the acute angle cutting edges can interact with the
obstruction differently than a perpendicular cutting edge. The
acute angle cutting edge may result in sharper engagement features
and more effective grabbing surfaces than perpendicular cutting
edges. In some cases, the acute angle cutting edge provides more of
a scraping action that is more effective for scraping a surface of
the obstruction compared to a perpendicular cutting edge. In some
cases, the acute angle cutting edge provides more of a gouging
action that is more effective for gouging the obstruction compared
to a perpendicular cutting edge. In some cases, the acute angle
cutting edge provides a higher grabbing strength to the tractor
compared to a perpendicular cutting edge.
[0061] According to some embodiments, a laser cutting technique is
used to form very small kerfs or slits with the tube/sheet. For
example, a laser beam can be used to form kerfs/slits having widths
of 0.001 inches or less (e.g., 0.0009, 0.0008, 0.0005 or 0.0001
inches). The opening between feature (e.g., engagement features) of
the tube/sheet can be spaced accordingly. Forming very small
kerfs/slits instead of larger openings may allow for formation of
the various features (e.g., engagement features) of the tractor
without substantial damage to surfaces of the tractor. Furthermore,
forming very small kerfs/slits increase the efficiency of forming
the tractor. Additionally, forming very small kerfs/slits may
result in substantially no removal of material, which can result in
cost savings of the manufacturing process.
[0062] In some cases, the arrangement of the hoop connectors is
configured to provide a prescribed flexibility to the tractor
during operation. FIGS. 8A and 8B show plan views of unrolled
tractors having two different hoop connector 810, 810'
arrangements. As used herein a hoop 808 may refer to a row of
engagement members 806, 806'. In some variations the `row` of
engagement members (engagement features) is a single continuous row
that spirals around the flexible tube body. In FIG. 8A, the links
(e.g., hoop connectors) line up in phase (three per
hoop/circumference) with three engagement features between each
hoop connector of a given hoop. In FIG. 8B, there are three hoop
connectors per hoop/circumference and three engagement features
between each hoop connector of a given hoop (similar to FIG. 8A),
but the hoop connectors are out of phase with respect to each
other. That is, at least some of the hoop connectors of adjacent
hoops do not line up along the same plane. The flexibility (e.g.,
collapsibility) of the tractors of FIGS. 8A and 8B may differ such
that the pulling force required to roll the tractor around the
catheter edge will differ. In some applications, the required
pulling force is minimized.
[0063] In some applications, the grabbing device may be used in
combination with one or more other devices for removing the
obstruction. Returning to FIG. 3A, for example, the engagement
features may project beyond the catheter edge as it rolls over the
catheter edge. As the engagement features project outward, they may
"score/etch/texture" the obstruction in a way that make stress
concentration lines within the blockage. These stress concentration
lines may improve the post blockage removal flow dynamics (boundary
layer) using, for example, an angioplasty balloon for further
vessel dilation. For example, the texture/scoring may help highly
calcified plaques crack open with less balloon pressure and create
more uniform vessel expansion. The extent to which the engagement
features project from the catheter edge can correspond to the
extent of scoring on the blockage. One way of controlling the
extent to which the engagement features project from the catheter
edge is to control the size (e.g., height) and/or stiffness
(malleability) of material the engagement features.
[0064] The catheter may have design features such as column
strength, torque transmission, ability to travel over a guide wire,
ability to reach distant treatment sites in small vessels through
highly curvy (tortuous vessel). According to some embodiments, the
tractor is configured to allow the catheter to move and be guided
within a blood vessel with little to no hindrance from presence of
the tractor. For instance, the tractor can be configured to allow
the catheter to bend and twist normally so as to negotiate a small
bend radius (tight curve). Properties of the tractor can be chosen
to prevent or minimize impediment of the motion of the catheter
while being guided through the blood vessel. For example, a smaller
tractor wall thickness may increase the maneuverability of the
catheter compared to a thicker tractor wall thickness. A tractor
having a smaller profile can add very little thickness to the
grabbing device compared to the thickness of the catheter alone. In
particular, a thin tractor may only minimally increase the outer
and inner diameters of the grabbing device compared to the catheter
alone. This can allow the grabbing device to maneuver within the
blood vessel while minimizing damage to the blood vessel and
surrounding tissues. Furthermore, the access hole used to introduce
the grabbing device into the patient would be minimized. That is,
catheter-based technologies using smaller outer diameter catheters
(e.g., French size) can translate into less invasive
procedures.
[0065] The material of the tractor may affect the operation of the
grabbing device. For example, a tractor made of a more ductile
material may be able to bend and change shape when exposed to
forces during operation. For example, the pulling force placed on
the tractor may stretch the network of struts such that some of the
hoops, engagement features and/or hoop connectors become elongated
along the longitudinal axis of the catheter. In some cases,
engagement with the obstruction may cause a change in shape of the
engagement features. In some applications, it is preferable to have
a more ductile tractor. For example, it may be desirable to have
portions of the tractor to transition from a compressed form to a
more elongated (stretched) for during operation. FIG. 9 shows a
perspective view of a tractor that includes stretched 980 and
compressed 982 portions, where the ductile properties of the
material of the tractor causes some of the hoops to become
elongated when a pulling force is applied. This may allow the
tractor to deform to a smaller diameter when in the elongated
state, thereby facilitating the entry of the tractor within the
internal cavity of the catheter. In some application, it is
preferable to have a stiffer tractor. For example, it may be
desirable for the tractor to rigidly maintain its dimensions during
operation. In some embodiments, tractors made of steel or alloys of
steel are more ductile than tractors made of harder alloys such as
nickel titanium.
[0066] The tractor can be configured to interact with the catheter
in a prescribed manner. In some embodiments, the flexible tube of
the tractor has an inner diameter that is equal to or slightly
smaller (undersized) than the outer diameter of the catheter prior
to installation onto the catheter, such that the tractor closely
hugs the catheter surface when installed. An undersized flexible
tube may provide the most communication between the tractor and the
catheter, such that the tractor is stabilized by the catheter and
remain in relatively fixed position in relation to the catheter
until a sufficiently high pulling force is applied. In some cases,
the tractor can having an inner diameter of 0.001 inches greater
than the outer diameter of the catheter or less (e.g., 0.0009,
0.0008, 0.0007, 0.0006 or 0.0005 inches greater) may provide a
hand-in-glove fit. In some embodiments, the flexible tube of the
tractor is sufficiently larger than the outer diameter of the
catheter such that friction between the tractor and the catheter is
minimal, thereby reducing the force (rolling force) needed to roll
the tractor over the catheter edge. In some cases, the tractor can
having an inner diameter of more than 0.001 inches greater than the
outer diameter of the catheter (e.g., 0.0011, 0.002, 0.003, 0.005,
0.01 or 0.1 inches greater) may provide a tractor with a minimal
required rolling force. In some embodiments, a first portion of the
flexible tube has an inner diameter of 0.001 inches greater than
the outer diameter of the catheter or less, and a second portion of
the flexible tube has an inner diameter of more than 0.001 inches
greater than the outer diameter of the catheter. Such combinations
of various tractor inner diameters may provide optimal stability
with minimal required rolling force in certain applications.
[0067] In some embodiments, different portions of the flexible tube
can be in various compressed and expanded states. The compressed
and expanded states can be associated with different amounts of
stored energy. Examples of different compressed and expanded states
are described in U.S. Patent Application Publication No.
2018/0070968 A1, which is incorporated by reference herein in its
entirety. A flexible tube (or portions of the flexible tube) in
compressed and expanded states can have different outer and/or
inner diameters. For example, the inner diameter of the flexible
tube (or a portion thereof) in an expanded state may be 1.5 times
greater than the outer diameter of the catheter or greater (e.g.,
1.6, 1.7, 1.8, 1.9, 2.0, 2.5, 3.0 or 4.0 times greater). In such
cases, the expanded diameter may increase the grabbing capacity of
the grabbing device. In some embodiments, the grabbing capacity may
increase by at least four times the volume for each double in
expansion of the outer diameter of the flexible tube relative to
the outer diameter of the catheter. In some applications, the outer
diameter of the flexible tube (or portions thereof) is configured
to expand when released from a compressed state. In such cases, the
grabbing device may be constrained by a delivery sheath to maintain
an outer diameter of the flexible tube until use (expansion).
[0068] In some cases, the flexible tube includes one or more
markers that can be used to identify a position of the grabbing
device within the blood vessel. In some instances, the marker(s) is
made of a radio-opaque material, which can be detectable using
radio transmission imaging. The marker(s) may be part of the
network of struts and hoops, or may be a separate member that is
added to the flexible tube. In some embodiments, the marker is a
band as part of the grabbing device. In some cases, the marker(s)
is located near a proximal end of the flexible tube within the
internal cavity of the catheter. Examples of markers are described
in U.S. Patent Application Publication No. 2018/0070968 A1 and U.S.
Pat. No. 10,028,759 B2, each of which is incorporated by reference
herein in its entirety.
[0069] Table 1 summarizes how some of properties of a grabbing
device may affect various functions of the grabbing device.
TABLE-US-00001 TABLE 1 Effect on Grabbing Device Stability/
Grabbing Grabbing Durability on Strength Strength Catheter outside
of Rolling Dense Soft tracking catheter (pre- Radio- Property force
Obstruction Obstruction (pre-roll) roll) opacity Material Steel
(304) higher increase No effect good best increase Nickel lower
decrease No effect better good decrease Titanium Wall thickness
thicker increase increase decrease worse increase increase thinner
decrease decrease increase better decrease decrease Number of
hoops/cm length increase No effect decrease increase better
increase No effect decrease No effect increase decrease worse
decrease No effect Number of Waves/cm increase decrease decrease
increase No effect No effect No effect decrease increase increase
decrease No effect No effect No effect Number of Connections per
perimeter increase No effect decrease increase decrease increase No
effect decrease No effect increase decrease increase decrease No
effect Hoop Minimal decrease Minimal decrease No effect No effect
Connection effect alignment Engagement Feature Height taller No
effect Significant increase decrease No effect No effect Increase
Engagement No effect increase No effect No effect Minimal No effect
Feature tip effect shape (pointy) Engagement Increase minimal
increase No effect Minimal increase Feature width effect (wider)
Proximal No effect No effect No effect No effect No effect increase
markers (bigger) Off axis laser No effect No effect No effect No
effect No effect No effect cut (non- perpendicular)
[0070] Regarding the type of material, Table 1 indicates that in
some cases a tractor (flexible tube) made of a relatively ductile
material (SAE 304 stainless steel) can provide a grabbing device
having a higher grabbing strength for a dense obstruction, higher
stability/durability, and higher radio-opacity compared to a
tractor made of a less ductile material (nickel titanium alloy).
Table 1 indicates that in some cases a tractor made of a relatively
rigid material (nickel titanium alloy) can provide a grabbing
device having a lower required rolling force and improved catheter
tracking (ability to allow catheter to move freely) compared to a
tractor made of a less rigid material (SAE 304 stainless steel).
Table 1 indicates that in some cases the tractor material has
substantially no effect on the grabbing strength for soft
obstructions of the grabbing device.
[0071] Regarding the wall thickness of the tractor, Table 1
indicates that in some cases a tractor (flexible tube) having a
relatively thick wall thickness can provide a grabbing device
having a higher grabbing strength for a dense obstruction, higher
stability/durability, and higher radio-opacity compared to a
tractor having a relatively thin wall thickness. Table 1 indicates
that in some cases a tractor having a relatively thin wall
thickness can provide a grabbing device having a lower required
rolling force, higher grabbing strength for a soft obstruction, and
improved catheter tracking compared to a tractor having a
relatively thin wall thickness.
[0072] Regarding the density of hoops, Table 1 indicates that in
some cases a tractor having a higher hoop density (greater number
of hoops per centimeter length) can provide a grabbing device
having a higher grabbing strength for soft obstructions, improved
catheter tracking, and higher stability/durability compared to a
tractor having a lower hoop density. Table 1 indicates that in some
cases a tractor having a lower hoop density (lower number of hoops
per centimeter length) can provide a grabbing device having a
higher grabbing strength for dense obstructions compared to a
tractor having a greater hoop density. Table 1 indicates that in
some cases the hoop density has substantially no effect on the
rolling force, and radio-opacity of the grabbing device.
[0073] Regarding the density of engagement features, Table 1
indicates that in some cases a tractor having a higher engagement
feature density (greater number of engagement features per
centimeter) can provide a grabbing device having a lower required
rolling force and a higher grabbing strength for soft obstructions
compared to a tractor having a lower engagement feature density.
Table 1 indicates that in some cases a tractor having a lower
engagement feature density (lower number of engagement features per
centimeter) can provide a grabbing device having a higher grabbing
strength for dense obstructions compared to a tractor having a
higher engagement feature density. Table 1 indicates that in some
cases the density of engagement features has substantially no
effect on the catheter tracking, stability/durability and the
radio-opacity of the grabbing device.
[0074] Regarding the density of hoop connectors, Table 1 indicates
that in some cases a tractor having a higher hoop connector density
(greater number of hoop connectors along a perimeter of the
tractor) can provide a grabbing device having a lower required
rolling force and a higher grabbing strength for soft obstructions
and higher stability/durability compared to a tractor having a
lower hoop connector density. Table 1 indicates that in some cases
a tractor having a lower hoop connector density (lower number of
hoop connectors along a perimeter of the tractor) can provide a
grabbing device having a higher grabbing strength for dense
obstructions and improved catheter tracking compared to a tractor
having a hoop connector density. Table 1 indicates that in some
cases the density of hoop connectors has substantially no effect on
the rolling force and the radio-opacity of the grabbing device.
[0075] Regarding the arrangement of hoop connectors, Table 1
indicates that in some cases a tractor having more hoop connectors
that are aligned (as opposed to offset from each other) can
decrease the grabbing strength of dense obstructions and decrease
the catheter tracking compared to a tractor having less hoop
connectors that are aligned. Table 1 indicates that in some cases a
tractor having more or less hoop connectors that are aligned has
minimal effect on the rolling force of the tractor and on the
grabbing strength of soft obstructions of the grabbing device.
Table 1 indicates that in some cases a tractor having more or less
hoop connectors that are aligned has substantially no effect on the
stability/durability and radio-opacity of the grabbing device.
[0076] Regarding the height of engagement features, Table 1
indicates that in some cases a tractor having engagement features
with greater heights (taller) can significantly increase the
grabbing strength of dense obstructions and increase the grabbing
strength of soft obstructions compared to a tractor having lesser
heights. Table 1 indicates that in some cases the height of the
engagement feature of a tractor has substantially no effect on the
rolling force, the stability/durability and the radio-opacity of
the grabbing device.
[0077] Regarding the shape of the engagement features, Table 1
indicates that in some cases a tractor having more pointed
engagement features (e.g., sharper) can significantly increase the
grabbing strength of dense obstructions and minimally effects the
stability/durability of the grabbing device. Table 1 indicates that
in some cases the pointedness (sharpness) of the engagement feature
of a tractor has substantially no effect on the rolling force,
grabbing strength of soft obstructions, catheter tracking and
radio-opacity of the grabbing device.
[0078] Regarding proximal markers, Table 1 indicates that in some
cases a tractor having a radio-opaque marker at or near the
proximal end of the flexible tube has substantially no effect on
the on the rolling force, grabbing strength of dense or soft
obstructions, catheter tracking and stability/durability of the
grabbing device.
[0079] Regarding the cross sectional angle of the cutting edges of
engagement features, Table 1 indicates that in some cases a tractor
having engagement features with a greater number of acute cutting
edges (e.g., less than 90 degrees) can have substantially no effect
on the rolling force, grabbing strength of dense or soft
obstructions, catheter tracking, stability/durability and
radio-opacity of the grabbing device.
[0080] According to some embodiments, a grabbing device effective
for capturing an obstruction from a blood vessel has a tractor with
3 to 5 engagement features per centimeter (cm) length, 2 to 3 hoops
per centimeter length, and 0.5 engagement features per millimeter
(mm) per hoop perimeter.
Example 1
[0081] A grabbing device was made according to the following
specification:
TABLE-US-00002 Material SAE 304 stainless steel Tractor wall
thickness 0.001 inches Tractor outer diameter 1.64 mm (0.64 inches)
Tractor inner diameter 1.6 mm (0.62 inches) Engagement feature
heights 3 mm Engagement feature widths 0.0015 inches Hoop density 3
hoops per cm Engagement feature density 18 engagement features per
hoop perimeter Hoop connector Repeated arrangement of Hoops 1 and
2, arrangement where: Hoop 1: 3 connectors equally spaced (5
engagement features between each hoop connector Hoop 2: 3
connectors shifted by 3 engagement features with respect to Hoop 1;
18 engagement features per perimeter
Example 2
[0082] A grabbing device was made according to the following
specification:
TABLE-US-00003 Material Nickel titanium alloy Tractor wall
thickness 0.001 inches Tractor outer diameter 1.64 mm (0.64 inches)
Tractor inner diameter 1.6 mm (0.62 inches) Engagement feature
heights 3 mm Engagement feature widths 0.002 inches Hoop density 3
hoops per cm Engagement feature density 18 engagement features per
hoop perimeter Hoop connector Repeated arrangement of Hoops 1 and
2, arrangement where: Hoop 1: 3 connectors equally spaced (5
engagement features between each hoop connector Hoop 2: 3
connectors shifted by 3 engagement features with respect to Hoop 1;
18 engagement features per perimeter
Example 3
[0083] A grabbing device was made according to the following
specification:
TABLE-US-00004 Material SAE 304 stainless steel Tractor wall
thickness 0.00075 inches Tractor outer diameter 1.64 mm (0.64
inches) Tractor inner diameter 1.6 mm (0.625 inches) Engagement
feature heights 3 mm Engagement feature widths 0.002 inches Hoop
density 3 hoops per cm Engagement feature density 18 engagement
features per hoop perimeter Hoop connector Repeated arrangement of
Hoops 1 and 2, arrangement where: Hoop 1: 3 connectors equally
spaced (5 engagement features between each hoop connector Hoop 2: 3
connectors shifted by 3 engagement features with respect to Hoop 1;
18 engagement features per perimeter
[0084] Any of the methods (including those associated with user
interfaces) described herein may be implemented as software,
hardware or firmware, and may be described as a non-transitory
computer-readable storage medium storing a set of instructions
capable of being executed by a processor (e.g., of a computer,
tablet, smartphone, etc.), that when executed by the processor
causes the processor to control perform any of the steps, including
but not limited to: displaying, communicating with the user,
analyzing, modifying parameters (including timing, frequency,
intensity, etc.), determining, alerting, or the like.
[0085] When a feature or element is herein referred to as being
"on" another feature or element, it can be directly on the other
feature or element or intervening features and/or elements may also
be present. In contrast, when a feature or element is referred to
as being "directly on" another feature or element, there are no
intervening features or elements present. It will also be
understood that, when a feature or element is referred to as being
"connected", "attached" or "coupled" to another feature or element,
it can be directly connected, attached or coupled to the other
feature or element or intervening features or elements may be
present. In contrast, when a feature or element is referred to as
being "directly connected", "directly attached" or "directly
coupled" to another feature or element, there are no intervening
features or elements present. Although described or shown with
respect to one embodiment, the features and elements so described
or shown can apply to other embodiments. It will also be
appreciated by those of skill in the art that references to a
structure or feature that is disposed "adjacent" another feature
may have portions that overlap or underlie the adjacent
feature.
[0086] Terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting of
the invention. For example, as used herein, the singular forms "a",
"an" and "the" are intended to include the plural forms as well,
unless the context clearly indicates otherwise. It will be further
understood that the terms "comprises" and/or "comprising," when
used in this specification, specify the presence of stated
features, steps, operations, elements, and/or components, but do
not preclude the presence or addition of one or more other
features, steps, operations, elements, components, and/or groups
thereof. As used herein, the term "and/or" includes any and all
combinations of one or more of the associated listed items and may
be abbreviated as "/".
[0087] Spatially relative terms, such as "under", "below", "lower",
"over", "upper" and the like, may be used herein for ease of
description to describe one element or feature's relationship to
another element(s) or feature(s) as illustrated in the figures. It
will be understood that the spatially relative terms are intended
to encompass different orientations of the device in use or
operation in addition to the orientation depicted in the figures.
For example, if a device in the figures is inverted, elements
described as "under" or "beneath" other elements or features would
then be oriented "over" the other elements or features. Thus, the
exemplary term "under" can encompass both an orientation of over
and under. The device may be otherwise oriented (rotated 90 degrees
or at other orientations) and the spatially relative descriptors
used herein interpreted accordingly. Similarly, the terms
"upwardly", "downwardly", "vertical", "horizontal" and the like are
used herein for the purpose of explanation only unless specifically
indicated otherwise.
[0088] Although the terms "first" and "second" may be used herein
to describe various features/elements (including steps), these
features/elements should not be limited by these terms, unless the
context indicates otherwise. These terms may be used to distinguish
one feature/element from another feature/element. Thus, a first
feature/element discussed below could be termed a second
feature/element, and similarly, a second feature/element discussed
below could be termed a first feature/element without departing
from the teachings of the present invention.
[0089] Throughout this specification and the claims which follow,
unless the context requires otherwise, the word "comprise", and
variations such as "comprises" and "comprising" means various
components can be co-jointly employed in the methods and articles
(e.g., compositions and apparatuses including device and methods).
For example, the term "comprising" will be understood to imply the
inclusion of any stated elements or steps but not the exclusion of
any other elements or steps.
[0090] In general, any of the apparatuses and methods described
herein should be understood to be inclusive, but all or a sub-set
of the components and/or steps may alternatively be exclusive, and
may be expressed as "consisting of" or alternatively "consisting
essentially of" the various components, steps, sub-components or
sub-steps.
[0091] As used herein in the specification and claims, including as
used in the examples and unless otherwise expressly specified, all
numbers may be read as if prefaced by the word "about" or
"approximately," even if the term does not expressly appear. The
phrase "about" or "approximately" may be used when describing
magnitude and/or position to indicate that the value and/or
position described is within a reasonable expected range of values
and/or positions. For example, a numeric value may have a value
that is +/-0.1% of the stated value (or range of values), +/-1% of
the stated value (or range of values), +/-2% of the stated value
(or range of values), +/-5% of the stated value (or range of
values), +/-10% of the stated value (or range of values), etc. Any
numerical values given herein should also be understood to include
about or approximately that value, unless the context indicates
otherwise. For example, if the value "10" is disclosed, then "about
10" is also disclosed. Any numerical range recited herein is
intended to include all sub-ranges subsumed therein. It is also
understood that when a value is disclosed that "less than or equal
to" the value, "greater than or equal to the value" and possible
ranges between values are also disclosed, as appropriately
understood by the skilled artisan. For example, if the value "X" is
disclosed the "less than or equal to X" as well as "greater than or
equal to X" (e.g., where X is a numerical value) is also disclosed.
It is also understood that the throughout the application, data is
provided in a number of different formats, and that this data,
represents endpoints and starting points, and ranges for any
combination of the data points. For example, if a particular data
point "10" and a particular data point "15" are disclosed, it is
understood that greater than, greater than or equal to, less than,
less than or equal to, and equal to 10 and 15 are considered
disclosed as well as between 10 and 15. It is also understood that
each unit between two particular units are also disclosed. For
example, if 10 and 15 are disclosed, then 11, 12, 13, and 14 are
also disclosed.
[0092] The examples and illustrations included herein show, by way
of illustration and not of limitation, specific embodiments in
which the subject matter may be practiced. As mentioned, other
embodiments may be utilized and derived there from, such that
structural and logical substitutions and changes may be made
without departing from the scope of this disclosure. Such
embodiments of the inventive subject matter may be referred to
herein individually or collectively by the term "invention" merely
for convenience and without intending to voluntarily limit the
scope of this application to any single invention or inventive
concept, if more than one is, in fact, disclosed. Thus, although
specific embodiments have been illustrated and described herein,
any arrangement calculated to achieve the same purpose may be
substituted for the specific embodiments shown. This disclosure is
intended to cover any and all adaptations or variations of various
embodiments. Combinations of the above embodiments, and other
embodiments not specifically described herein, will be apparent to
those of skill in the art upon reviewing the above description.
Therefore, the foregoing description is provided primarily for
exemplary purposes and should not be interpreted to limit the scope
of the invention as it is set forth in the claims.
* * * * *