U.S. patent application number 16/545842 was filed with the patent office on 2019-12-05 for devices and methods for minimally invasive tissue removal.
This patent application is currently assigned to ANGIOWORKS MEDICAL B.V.. The applicant listed for this patent is ANGIOWORKS MEDICAL B.V.. Invention is credited to Itzhak AVNERI, Shahar AVNERI, Rami LORE, Gonen YUVAL.
Application Number | 20190365411 16/545842 |
Document ID | / |
Family ID | 56507622 |
Filed Date | 2019-12-05 |
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United States Patent
Application |
20190365411 |
Kind Code |
A1 |
AVNERI; Itzhak ; et
al. |
December 5, 2019 |
DEVICES AND METHODS FOR MINIMALLY INVASIVE TISSUE REMOVAL
Abstract
A medical device for minimally invasive removal of tissue from a
body lumen, can include: a sheath having a proximal and a distal
end; and a tool configured to pass through the sheath and
configured to transition from a crimped state to a deployed state
and to a closed state, wherein the tool forms an aperture at a
distal end, the distal end of the tool having at least one tube
loop and at least one wire loop, wherein the tool is configured to
dissect tissue in the deployed state.
Inventors: |
AVNERI; Itzhak; (Tel Aviv,
IL) ; LORE; Rami; (Kiyat Tivon, IL) ; YUVAL;
Gonen; (Kiyat Tivon, IL) ; AVNERI; Shahar;
(Herzliya, IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ANGIOWORKS MEDICAL B.V. |
Amsterdam |
|
NL |
|
|
Assignee: |
ANGIOWORKS MEDICAL B.V.
Amsterdam
NL
|
Family ID: |
56507622 |
Appl. No.: |
16/545842 |
Filed: |
August 20, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
15639958 |
Jun 30, 2017 |
10426512 |
|
|
16545842 |
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15167629 |
May 27, 2016 |
9693795 |
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15639958 |
|
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62167089 |
May 27, 2015 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B 17/32056 20130101;
A61B 17/320725 20130101; A61B 2017/2215 20130101; A61B 17/221
20130101; A61B 2017/00778 20130101; A61B 2017/320741 20130101 |
International
Class: |
A61B 17/3207 20060101
A61B017/3207; A61B 17/3205 20060101 A61B017/3205; A61B 17/221
20060101 A61B017/221 |
Claims
1. A medical device for minimally invasive removal of tissue from a
body lumen, comprising: a sheath having a proximal and a distal
end; and a tool configured to pass through the sheath and
configured to transition from a crimped state to a deployed state
and to a closed state, wherein the tool forms an aperture at a
distal end, the distal end of the tool having at least one tube
loop and at least one wire loop, wherein the tool is configured to
dissect tissue in the deployed state.
2-30. (canceled)
31. The device of claim 1, wherein the tool in the deployed state
has a radial force and wherein the tool is configured to allow
adjustment of at least one of the radial force and the
aperture.
32. The device of claim 31, wherein the at least one tube loop has
an adjustable outward angle and wherein the adjustment of the
radial force takes place by pushing the at least one wire loop
along a longitudinal axis of the sheath.
33. The device of claim 31, wherein the at least one wire loop has
varying degrees of rigidity and wherein the adjustment of the
radial force is by shifting a location of segments of the at least
one wire loop.
34. The device of claim 1, the at least one tube loop and the at
least one wire loop comprises three levels of loops.
35. The device of claim 34, wherein the tool comprises a first
level of at least one tube loop and a second level of at least one
tube loop that proceeds from a distal end of the first level of the
at least one tube loop in the deployed state, and wherein the at
least one wire loop extends from the distal end of the second level
of at least one tube loop in the deployed state.
36. The device of claim 1, wherein the tool includes a directional
feature that ensures order and orientation of the at least one tube
loop.
37. The device of claim 36, further comprising a multilumen segment
that is configured to house at least a portion of the at least one
tube loop, wherein the directional feature includes the tube loop
having a portion with an oval cross-sectional shape and a central
lumen of the multilumen segment having an oval cross-sectional
shape.
38. The device of claim 1, further comprising a multilumen segment
that is configured to house at least a portion of the tube
loop.
39. The device of claim 38, further comprising connections between
each of adjacent tube loops, the connections being distal to the
multilumen segment.
40. The device of claim 1, wherein the at least one tube loop forms
a cross-section of the device that has a generally circular
shape.
41. The device of claim 1, wherein the at least one tube loop is
expandable.
42. The device of claim 41, wherein the at least one tube loop is
radially expandable.
43. The device of claim 1, wherein the tool is at least one of
self-expandably, slideably and rotatably disposed in the
sheath.
44. The device of claim 1, wherein the at least one tube loop is
configured to remove a plaque from an arterial wall.
45. The device of claim 1, wherein the at least one tube loop is
adjustable.
46. The device of claim 1, wherein the at least one tube loop
comprises a sharp element at the distal end.
47. The device of claim 46, wherein the distal end of the at least
one tube loop includes a blunt portion that is oriented away from
an arterial wall of the body lumen and a sharp portion having the
sharp element that protrudes into the tissue to be removed.
48. The device of claim 1, wherein the at least one tube loop is an
arch having two legs along a longitudinal axis of the sheath in the
deployed state.
49. The device of claim 48, wherein the arch has a curved
symmetrical structure spanning an opening.
50. The device of claim 1, wherein the at least one wire loop is a
monofilament wire of shape memory material.
51. The device of claim 50, wherein the at least one wire loop is
made of nitinol.
52. The device of claim 1, wherein the at least one tube loop is
hollow to surround the at least one wire loop in the crimped state,
and wherein the at least one wire loop is exit-able/extendible from
the at least one tube loop.
53. The device of claim 1, wherein a diameter of the at least one
wire loop is less than an inner diameter of the at least one tube
loop.
54. The device of claim 1, wherein the minimally invasive removal
of tissue is percutaneous access removal of tissue.
55. The device of claim 1, wherein the device is configured for the
minimally invasive removal of tissue in an endarterectomy.
56. The device of claim 1, wherein the device is configured for the
minimally invasive removal of blood clot in an embolectomy.
57. The device of claim 1, wherein the device is configured for the
minimally invasive removal of renal calculi in an urolithotomy.
58. The device of claim 1, wherein the device is configured for the
minimally invasive removal of tissue in a pulmonary embolism.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional
Application No. 62/167,089 filed May 27, 2015, which is
incorporated herein in its entirety by reference.
TECHNICAL FIELD
[0002] This application relates to devices and methods for
minimally invasive tissue removal, and specifically for removing
tissue using remote endarterectomy.
BACKGROUND
[0003] The normal human artery is composed of three main layers.
The innermost layer lining the artery, in contact with the blood,
is the intima. This is a single cell layer of endothelial cells,
which among other functions regulates vascular tone, platelet
activation and thrombus formation, monocyte adhesion and
inflammation and vascular remodeling. The media--the middle layer,
consists of several layers of smooth muscle cells and elastic
fibers. The outermost layer is the adventitia, which is mainly
composed of connective tissue containing small blood vessels and
nerves.
[0004] Atherosclerosis is one of the major causes of cardiovascular
cerebrovascular and peripheral vascular morbidity and mortality. It
is a disease of large and medium-sized muscular arteries, which is
characterized by the formation of discrete lesions called
atherosclerotic plaques, or atheromas, thought to be caused by
injury to the endothelium. An atheroma is a buildup of lipids,
cholesterol, calcium, and cellular debris within the 1intima of the
vessel wall. Atherosclerotic buildup also results in vascular
remodeling, acute and chronic luminal obstruction, abnormalities of
blood flow and diminished oxygen supply to target organs.
[0005] Manifestations of atherosclerotic disease depend on the
affected organs and the type of lesions. Chronically narrowed
arteries give rise to symptoms of insufficient blood flow such as
angina pectoris (chest pain during exertion), intermittent
claudication (leg pain during exertion), and chronic leg ulcers.
Acute events can occur as a result as of plaque rupture and
thrombosis, which might totally clog the artery as in most cases of
acute myocardial infarction (heart attack), or as a result of
distal embolization of plaque fragments, as in many cases of
stroke.
[0006] Treatment of atherosclerosis depends on many factors
including the location of symptomatic lesions, the severity of
symptoms, and their dynamics.
[0007] Acute obstruction events usually require acute intervention.
For acute coronary events, treatment is urgent percutaneous
angioplasty (balloon dilation of the obstructed artery) and
stenting. Depending on the time from the beginning of symptoms,
acute ischemic stroke is sometimes treated urgently by percutaneous
mechanical removal of the obstruction or injection of compounds
that lyse it (tPA, streptokinase), but in many such cases treatment
will only focus on the prevention of future events. Acute limb
ischemia is also treated by urgent revascularization, either
percutaneous or surgical.
[0008] The treatment of chronic obstruction can include an
interventional procedure, which may be surgical or percutaneous and
is aimed at revascularization of the target organs and removal of a
potential source of emboli, if present.
[0009] Surgical treatments include bypass surgery, more commonly
used for coronary and lower limb arteries, and endarterectomy,
which is used for limb and carotid arteries, and involves opening
the artery and removing the plaque along with the intima.
Obviously, the disadvantage of surgery is its highly invasive
nature, the need for anesthesia, and the pain and stress involved
which make it unsuitable for certain patients.
[0010] Percutaneous procedures enable treating the lesions using
long catheters inserted to the arteries at a distant point such as
the groin arteries. The most common of these is placement of a
stent, a metal structure which is inserted to the artery in a
closed state and expanded within the lesion so as to keep the lumen
patent. This can be done with or without balloon angioplasty
(inflation of a balloon in the lesion to enlarge the lumen prior to
or following stent placement). The main disadvantage of angioplasty
and stenting is that the plaque remains in the artery. This has
several deleterious consequences. First--in carotid stenting, many
of the post stenting strokes are caused not during the procedure,
but after it, and are probably related to plaque material squeezing
through the cells of the stent and embolizing to the brain (a
phenomenon known as the "mashed potato effect"). Second--in many
cases the plaque encroaches on the stent and does not enable
attainment of a normal vascular lumen. This in turn affects flow
dynamics and shear stress, which may enhance atherogenesis and
cause restenosis. Third--the plaque material itself contains many
inflammatory and prothrombotic substances. This may be the reason
for the high rate of restenosis experienced after stenting.
[0011] What is needed are methods, devices and systems for
improving procedures for removing tissue.
SUMMARY
[0012] A medical device for minimally invasive removal of tissue
from a body lumen, can include: a sheath having a proximal and a
distal end; and a tool configured to pass through the sheath and
configured to transition from a crimped state to a deployed state
and to a closed state, wherein the tool forms an aperture at a
distal end, the distal end of the tool having at least one tube
loop and at least one wire loop. The tool can be configured to
dissect tissue in the deployed state.
[0013] The tissue can be a lesion and the tool can be configured to
extend along the lesion and can be configured to dissect around the
lesion along a longitudinal axis of the body lumen.
[0014] The tool can be configured to close the aperture distal to
the dissected tissue to contain the tissue and the tool can be
configured to remove the tissue in the closed state.
[0015] The tool can include a plurality of tube loops and a
plurality of wire loops. The wire loops can be moveable to a
plurality of locations with respect to a radial axis of the sheath,
the wire loops can be configured to contact each other, and the
wire loops can be configured to close such that a scissor action
between adjacent wires is operable to cut intima of the tissue.
[0016] In a radial axis of the sheath, each wire loop can extend
under another wire loop and over another wire loop. Each tube loop
can have a first and a second wire loop, and from a distal end view
in the radial axis of the sheath, the second wire loop can extend
under the first wire loop in a clockwise direction of the radial
axis of the sheath.
[0017] Each of a first set of two opposing wire loops can extend
over one of a second set of opposing wire loops, and each of the
second set of opposing wire loops can extend under one of the first
set of opposing wire loops in a radial axis of the sheath. One wire
loop can extend over adjacent wire loops and an opposing wire loop
can extend under adjacent wire loops. Each wire loop can have a
pre-formed curvature around a radial axis of the sheath. The
curvature can be radially displaced from a longitudinal axis of the
sheath.
[0018] At least one of the wire loops can extend over at least
another wire loop and at least one of the wire loops can extend
under at least another of the wire loops in the radial axis of the
sheath.
[0019] A first wire loop can extend over all other wire loops and
other wire loops can be interlaced with adjacent wire loops in the
radial axis of the sheath. The first wire loop when retracted can
be configured to pass a center line of the body lumen.
[0020] Each tube loop can have a first wire loop that extends in a
counter-clockwise direction of the radial axis of the sheath and a
second wire loop that extends in a clockwise direction of the
radial axis of the sheath.
[0021] The first and second wire loops can cross each other in the
radial axis. The first and second wire loops may not cross each
other in the radial axis.
[0022] The at least one wire loop can be graded in the deployed
state. The graded wire loops can protrude from the distal end of
the sheath at varying distances.
[0023] The wire loops can have a graded distance between a most
distal wire loop distal end and a most proximal wire loop distal
end. The graded distance can provide improved entry of the tool to
subintimal space.
[0024] The at least one tube loop can have a window that allows for
passage of the at least one wire loop. The window of the at least
one tube loop can be a distal window and can outline two holes.
[0025] The at least one tube loop can have a longitudinal axis, and
the distal window can have a length along the longitudinal axis in
a range between about 0.5 to about 5 times a diameter of the at
least one tube loop.
[0026] The at least one tube loop can include four spatially
equidistant loops.
[0027] The at least one tube loop comprises anywhere from two
through eight loops. The device can further include: a handle at a
proximal portion of the sheath; and a multilumen tube disposed
inside at least a portion of the sheath, the multilumen tube being
configured to interface with the at least one tube loop. The tool
can be configured to pass through the distal end of the sheath
using movement of the handle. The handle can include an elongate
casing having a wire handle connected to the at least one tube loop
and a slot for the wire handle to slide, and the multilumen tube
can be disposed inside at least a portion of the casing.
[0028] The device can further include a sac that is configured to
enclose the at least one tube loop and at least one wire loop in
the closed state. At least a portion of the sac can be disposed
inside the sheath. At least a portion of the sac can be disposed
outside the sheath.
[0029] The device can further include a ring that is slideably
disposed between the multilumen tube and the sheath, where the sac
is connected to the ring. The sac can be connected to at least one
portion of the distal end of the at least one tube loop. The sac
can be connected to at least one portion of the distal end of the
at least one wire loop.
[0030] The device can further include a cutting element that is
located at the distal end of the at least one tube loop. The
cutting element can be configured to expand radially with expansion
of the aperture. The cutting element can surround the aperture of
the tool.
[0031] The cutting element can include a blunt and a sharp state.
The cutting element can be configured to transition between blunt
and sharp states upon the aperture substantially closing.
[0032] The tool in the deployed state can have a radial force and
the tool is configured to allow adjustment of at least one of the
radial force and the aperture. The at least one tube loop can have
an adjustable outward angle and the adjustment of the radial force
can take place by pushing the at least one wire loop along a
longitudinal axis of the sheath. The at least one wire loop can
have varying degrees of rigidity and the adjustment of the radial
force can be by shifting a location of segments of the at least one
wire loop.
[0033] The at least one tube loop and the at least one wire loop
can include three levels of loops. The tool can include a first
level of at least one tube loop and a second level of at least one
tube loop that proceeds from a distal end of the first level of the
at least one tube loop in the deployed state. The at least one wire
loop can extend from the distal end of the second level of at least
one tube loop in the deployed state.
[0034] The tool can include a directional feature that ensures
order and orientation of the at least one tube loop. The device can
further include a multilumen segment that is configured to house at
least a portion of the at least one tube loop. The directional
feature can include the tube loop having a portion with an oval
cross-sectional shape and a central lumen of the multilumen segment
having an oval cross-sectional shape.
[0035] The device can further include a multilumen segment that is
configured to house at least a portion of the tube loop. The device
can further include connections between each of adjacent tube
loops. The connections can be distal to the multilumen segment.
[0036] The at least one tube loop can form a cross-section of the
device that has a generally circular shape. The at least one tube
loop can be expandable. The at least one tube loop can be radially
expandable.
[0037] The tool can be at least one of self-expandably, slideably
and rotatably disposed in the sheath. The at least one tube loop
can be configured to remove a plaque from an arterial wall. The at
least one tube loop can be adjustable.
[0038] The at least one tube loop can include a sharp element at
the distal end. The distal end of the at least one tube loop can
include a blunt portion that is oriented away from an arterial wall
of the body lumen and a sharp portion having the sharp element that
protrudes into the tissue to be removed.
[0039] The at least one tube loop can be an arch having two legs
along a longitudinal axis of the sheath in the deployed state. The
arch can have a curved symmetrical structure spanning an
opening.
[0040] The at least one wire loop can be a monofilament wire of
shape memory material. The at least one wire loop can be made of
nitinol.
[0041] The at least one tube loop can be hollow to surround the at
least one wire loop in the crimped state, and the at least one wire
loop can be exit-able/extendible from the at least one tube
loop.
[0042] A diameter of the at least one wire loop can be less than an
inner diameter of the at least one tube loop. The minimally
invasive removal of tissue can be percutaneous access removal of
tissue.
[0043] The device can be configured for the minimally invasive
removal of tissue in an endarterectomy. The device can be
configured for the minimally invasive removal of blood clot in an
embolectomy. The device can be configured for the minimally
invasive removal of renal calculi in an urolithotomy. The device
can be configured for the minimally invasive removal of tissue in a
pulmonary embolism.
[0044] A method for minimally invasively removing tissue from a
body lumen, can include: passing a tool through a sheath that is
configured to transition from a crimped state to a deployed state
and to a closed state, a distal end of the tool having at least one
tube loop and at least one wire loop; forming an aperture at a
distal end of the tool in the deployed state; and dissecting tissue
in the deployed state.
[0045] The forming the aperture step can include extending the wire
loops. The extending the at least one wire loop can include
advancing the at least one wire loops through at least one window
of the at least one tube loop. The passing the tool through the
sheath includes transitioning to an expanded state.
[0046] In the method, the tissue can be a lesion and the method can
further include extending the tool along the lesion. The dissecting
can include dissecting the lesion along a longitudinal axis of the
body lumen.
[0047] The method can further include: closing the aperture distal
to the dissected tissue to contain the tissue; and removing the
tissue in the closed state.
[0048] In the method, the tool can include a handle at a proximal
portion of the sheath; and a multilumen tube disposed inside at
least a portion of the sheath, the multilumen tube being configured
to interface with the at least one tube loop, and the method can
further include passing the tool through the distal end of the
sheath using movement of the handle. The handle can include an
elongate casing having a wire handle connected to the at least one
tube loop and a slot for the wire handle to slide, and the
multilumen tube can be disposed inside at least a portion of the
casing.
[0049] The method can further include enclosing the loops with a
sac in the closed state. The method can further include passing the
at least one wire loop through windows of the at least one tube
loop in the deployed state.
[0050] The method can further include utilizing a cutting element
to remove the tissue. The method can further include inserting a
wire loop into the subintimal space of the tissue; and threading a
leading wire loop distal end over a wire which has been inserted
into the subintimal space of the tissue.
[0051] The method can further include: housing at least a portion
of the at least one tube loop with a multilumen segment; and
providing connections between each of adjacent tube loops distal to
the multilumen segment.
[0052] The at least one tube loop can have a graded distance of the
distal ends for the tool's improved entry to the subintimal space
of the tissue.
[0053] The minimally invasive removal of tissue can include an
endarterectomy. The minimally invasive removal of tissue can
include an embolectomy. The minimally invasive removal of tissue
can treat a pulmonary embolism. The minimally invasive removal of
tissue can include a percutaneous procedure. The minimally invasive
removal of tissue can include a urolithotomy.
[0054] Additional features, advantages, and embodiments of the
invention are set forth or apparent from consideration of the
following detailed description, drawings and claims. Moreover, it
is to be understood that both the foregoing summary of the
invention and the following detailed description are examples and
intended to provide further explanation without limiting the scope
of the invention as claimed.
BRIEF DESCRIPTION OF DRAWINGS
[0055] FIG. 1A shows a longitudinal cross-section view of a medical
device for percutaneous removal of tissue in a crimped state,
according to an embodiment of the invention.
[0056] FIG. 1B shows a longitudinal cross-section view of a medical
device for percutaneous removal of tissue in a deployed state,
according to an embodiment of the invention.
[0057] FIG. 2A shows a distal end of a medical device for
percutaneous removal of tissue in a deployed state, according to an
embodiment of the invention.
[0058] FIG. 2B shows a perspective view of a medical device in a
deployed state, according to an embodiment of the invention.
[0059] FIG. 2C is a perspective end view of a deployed device,
according to an embodiment of the invention.
[0060] FIG. 2D is an end view of a device in a closed device,
closed beyond dissected tissue, according to an embodiment of the
invention.
[0061] FIG. 2E is a perspective view of a distal end of a tool in a
closed state, according to an embodiment of the invention.
[0062] FIG. 2F is a simplified schematic longitudinal cross section
through the end of tool showing the scissoring action of the wire
loops, according to an embodiment of the invention. FIGS. 3A shows
the site of an intended procedure just before insertion of device,
according to an embodiment of the invention.
[0063] FIG. 3B shows the site of an intended procedure just after
insertion of device, according to an embodiment of the
invention.
[0064] FIG. 3C shows the site of a procedure during deployment of
device, according to an embodiment of the invention.
[0065] FIG. 3D shows the site of a procedure at the end of
expansion of aperture of device, according to an embodiment of the
invention.
[0066] FIG. 3E shows the site of a procedure following expansion of
aperture and during advancement of device, according to an
embodiment of the invention.
[0067] FIG. 3F shows the site of a procedure following advancement
of device beyond blockage, according to an embodiment of the
invention.
[0068] FIG. 3G shows the site of a procedure following closure of
device beyond blockage, according to an embodiment of the
invention.
[0069] FIG. 3H shows the site of a procedure during removal of
device containing blockage tissue, according to an embodiment of
the invention.
[0070] FIG. 4a shows a schematic distal-end view of loops of the
device, according to an embodiment of the invention.
[0071] FIG. 4B shows a schematic distal-end view of loops of the
device, according to an embodiment of the invention.
[0072] FIG. 4C shows a schematic distal-end view of loops of the
device, according to an embodiment of the invention.
[0073] FIG. 4D shows a schematic distal-end view of loops having
bends in the cross-section of the device, according to an
embodiment of the invention.
[0074] FIG. 4E shows a schematic distal-end view of loops having
bends in the cross-section of the device, according to an
embodiment of the invention.
[0075] FIG. 4F shows a schematic distal-end view of loops having
bends in the cross-section of the device, according to an
embodiment of the invention.
[0076] FIG. 4G depicts a window of a tube loop as a single slot,
according to an embodiment of the invention.
[0077] FIG. 4H shows a window including two discrete holes,
according to an embodiment of the invention.
[0078] FIG. 5A shows a close-up perspective view of wire loops
coming from a tube loop, according to an embodiment of the
invention.
[0079] FIG. 5B shows a cross section side view of the tip of a
device in a deployed state inside an artery at the distal end of a
lesion, according to an embodiment of the invention.
[0080] FIG. 5C shows a cross section side view of the tip of a
device in a less deployed state than FIG. 5B inside an artery at
the distal end of a lesion, according to an embodiment of the
invention.
[0081] FIG. 5D shows a cross section side view of the tip of a
device in a less deployed state than FIGS. 5B and 5C inside an
artery at the distal end of a lesion, according to an embodiment of
the invention.
[0082] FIG. 6A shows a perspective view of a distal end of a device
with a cutting element in a deployed state, according to an
embodiment of the invention.
[0083] FIG. 6B shows the device of FIG. 6A in an expanded state,
according to an embodiment of the invention.
[0084] FIG. 6C shows the device of FIG. 6B in a constricted state
containing the tissue, according to an embodiment of the
invention.
[0085] FIG. 6D shows the device of FIG. 6C after the cutting
element has sheared the tissue, according to an embodiment of the
invention.
[0086] FIG. 7A shows a side view of a distal end of the loops of a
device, according to an embodiment of the invention.
[0087] FIG. 7B shows a side view of a distal end of the loops of a
device, according to an embodiment of the invention.
[0088] FIG. 8 shows a device in a deployed state having a sac,
according to an embodiment of the invention.
[0089] FIG. 9 shows a device in a deployed state having three
layers of loops, according to an embodiment of the invention.
[0090] FIG. 10 shows a schematic longitudinal section of a device
in a crimped state, according to an embodiment of the
invention.
[0091] FIG. 11 shows schematic cross sectional view of device at
the middle of a multilumen segment having a directional feature,
according to an embodiment of the invention.
[0092] FIG. 12A is a schematic 3D depiction of the distal end of
tube loops 18 in an almost crimped state of the device, according
to an embodiment of the invention.
[0093] FIG. 12B is a schematic 3D depiction of the distal end of
tube loops 18 in an almost deployed state of the device, according
to an embodiment of the invention.
[0094] FIG. 13 shows a distal end of the medical device in a
deployed state having graded loops, according to an embodiment of
the invention.
DETAILED DESCRIPTION
[0095] Some embodiments of the current invention are discussed in
detail below. In describing embodiments, specific terminology is
employed for the sake of clarity. However, the invention is not
intended to be limited to the specific terminology so selected. A
person skilled in the relevant art will recognize that other
equivalent components can be employed and other methods developed
without departing from the broad concepts of the current invention.
All references cited anywhere in this specification, including the
Background and Detailed Description sections, are incorporated by
reference as if each had been individually incorporated.
[0096] In accordance with current needs, embodiments of the present
invention provide a low profile device for performing percutaneous
subintimal remote endarterectomy, by opening an "aperture" proximal
to an atherosclerotic lesion, extending it distally to a long
distance, while dissecting tissue around the interior of the vessel
and containing it within a sheath, then closing the "aperture"
beyond the lesion, or at an arbitrary point along the lesion, and
removing the excised tissue from the patient's body.
[0097] An embodiment of an improved percutaneous remote
endarterectomy device 10 is depicted in FIGS. 1A & 1B, which
are simplified schematic drawings of longitudinal sections of
device 10 in its crimped and deployed states respectively. FIGS. 1A
and 1B show a device for minimally invasive removal of tissue from
a body lumen that can include a sheath 12 having a proximal end 14
and a distal end 16. The device can include a tool 41 configured to
pass through the sheath 12, and transition from a crimped state to
a deployed state and to a closed state. The tool 41 can form an
aperture at a distal end. The tool 41 can be configured to dissect
tissue in the deployed state. In an embodiment, the tissue can be a
lesion and the tool can be configured to extend along the lesion
and can be configured to dissect the lesion along a longitudinal
axis of the body lumen. Further, the tool can be configured to
dissect around the lesion along the longitudinal axis of the body
lumen. The tool can be configured to close the aperture distal to
the dissected tissue to contain the tissue. The tool can be
configured to remove the tissue in the closed state. The tool can
be at least one of self-expandably, slideably and rotatably
disposed in the sheath.
[0098] The distal end 43 of the tool 41 can have a tube loop 18 and
a wire loop 28. The distal end 43 of the tool 41 can include a
plurality of tube loops 18 and a plurality of wire loops 24.
Reference that is made to a tube loop or a wire loop is also meant
to include a plurality of tube loops and/or a plurality of wire
loops, respectively. The one or more wire loops 24 can extend from
a distal end 22 of the one or more tube loops 18. In an embodiment,
the plurality of tube loops can include anywhere from two through
eight loops. The at least one tube loops can be expandable in the
longitudinal and radial axis of the sheath.
[0099] The one or more tube loops can have a substantially linear
shape at a proximal end 20 along the longitudinal axis of the
sheath 12. The at least one tube loops can be expandable in
relation to the sheath in both a longitudinal and radial direction.
The at least one tube loop can be adjustable in relation to the at
least one wire loop. That is, at a stationary position, the at
least one wire loop can expand longitudinally and/or radially with
regard to the at least one tube loop.
[0100] More particularly, FIG. 1A is a schematic longitudinal
section of device 10 in its crimped state, mainly comprising the
following parts, from proximal to distal: handle 40, which operates
a multilumen tube 30, one or more tube loops 18 and one or more
wire loops 24, which are slideably disposed within a sheath 12
having proximal end 14 and distal end 16, and optionally an
atraumatic tip 17.
[0101] Tube loops 18 have proximal ends 20, and distal ends 22
having window 23. Wire loops 24 are slideably disposed within tube
loops 18, and have proximal ends 26, and distal ends 28, protruding
outwardly and distally through window 23 of tube loop distal ends
22.
[0102] The number of tube loops 18 and wire loops 24 can be equal,
and may be one or more, but is typically 3-5, preferably 4. For the
sake of clarity, only two of tube loops 18 and wire loops 24 are
shown in FIGS. 1A and 1B.
[0103] Multilumen tube 30 having proximal end 32 and distal end 34
may be slideably disposed within sheath 12 proximal to tube loops
18. Multilumen tube 30 may have a central lumen 31, and peripheral
lumens 35, typically numbering double the number of tube loops 18.
Proximal end 20 of tube loops 18 may be connected to distal end 34
of multilumen catheter 30, such that the lumens of tube loops 18
and multilumen catheter 30 are continuous, and wire loops 24 pass
through multilumen catheter 30, exiting at its proximal end 32, and
connecting to connector 33.
[0104] In an embodiment, multilumen catheter 30 can be omitted and
tube loops 18 made longer so as to span the length of sheath 12,
although the prior design saves in tube length and is therefore
more economical.
[0105] Device 10 may be controlled by a handle 40 comprised of an
elongate casing 42 which may have a short slot 44, a long slot 46,
and an opening 48. Casing 42 may be attached to proximal end 14 of
sheath 12. A tube handle 50 may be provided in the form of a
protrusion from proximal end 32 of multilumen catheter 30, and a
wire handle 52 may be provided in the form of a protrusion from
connector 33. Tube handle 50 may protrude through casing 42 via
short slot 44, and wire handle 52 may protrude through casing 42
via long slot 46.
[0106] Device 10 typically has a through lumen along its center,
enabling passage of a guidewire for navigation, guidance,
stabilization, manipulation, or other uses. The guidewire may be
passed through distal tip 16 of sheath 12, and central lumen 31 of
multilumen tube 30, and may exit device 10 proximally through
opening 48. A dedicated tube (not shown) may optionally be further
added to device 10 to define the through lumen and facilitate
guidewire passage through the above route or any other route.
[0107] Thus, the device 10 can include a handle 40 at a proximal
portion 49 of the device 10 and a multilumen tube 30 disposed
inside at least a portion of the sheath. The multilumen tube 30 can
be configured to interface with the at least one tube loop. The
tool 41 can be configured to pass through the distal end 16 of the
sheath 12 using movement of the handle 40. The multilumen tube 30
can be a multilumen sheath or a multilumen catheter. The handle can
include an elongate casing 42 having a wire handle 52 connected to
the at least one tube loop and a slot for the wire handle to slide.
The multilumen tube 30 can be disposed inside at least a portion of
the casing 42.
[0108] The above design of the handle 40 is a simplified basic
design described just as an example. Various different designs for
handles of endovascular devices as known in the art may be used to
increase control and precision of deployment, for example using cog
wheels and toothed rods to advance multilumen tube 30, and various
types of sliding or rotating latches or buttons to advance
connector 33.
[0109] In the crimped state of device 10, the distance D between
tube handle 50 and distal end of short slot 44 may be approximately
equal to the length of tube loops 18. This distance defines the
maximal length of endarterectomy which may be achieved in a single
deployment of device 10.
[0110] In the crimped state of device 10, the distance between wire
handle 52 and proximal end 32 of multilumen tube 30 is E. This
distance determines the maximal radial opening of distal end 43 of
tool 41 in the deployed state, by affecting the distance between
distal ends 22 of tube loops 18.
[0111] FIG. 1B is a schematic longitudinal section of device 10 in
its deployed state, and shows the same parts depicted in FIG. 1A,
including, from proximal to distal: handle 40, multilumen tube 30,
sheath 12, optional atraumatic tip 17, tube loops 18 and wire loops
24.
[0112] More particularly, in FIG. 1B, tube handle 50 was pushed to
the distal end of short slot 44, moving multilumen tube 30
distally, and passing tube loops 18 beyond distal tip 16. Wire
handle 52 was also pushed to distal end of long slot 46, deploying
wire loops 24 out of tube loops 18, thus opening an "aperture" 5.
Aperture 5 is defined by the opening created between deployed wire
loop ends 28 and tube loop ends 22.
[0113] FIG. 2A is a 3D depiction of the distal end of device 10,
having four tube loops 18 and wire loops 24, at the beginning of
deployment.
[0114] More particularly, FIG. 2A shows distal end 16 of sheath 12,
tube loops 18 with tube loops distal ends 22, windows 23, and wire
loop distal ends 28 protruding therethrough.
[0115] In FIG. 2A, deployment is partial, as tube loops 18 have not
yet fully extended radially beyond the perimeter of sheath 12.
Ideally, at full deployment, tube loops 18 extend radially at least
3-4 times the diameter of sheath 12, as seen in FIG. 2B.
[0116] In use, crimped device 10 is typically inserted
percutaneously into an artery, and advanced over a guidewire or via
a guiding catheter, under fluoroscopic guidance, towards a
previously identified atherosclerotic lesion requiring treatment.
Thus, the minimally invasive removal of tissue can be through
percutaneous access. That is, the device can be configured to be
used in percutaneous procedures and techniques.
[0117] Once distal end 16 of sheath 12 is positioned proximal to
the target lesion, typically at a distance of about 1-2 cm from the
lesion, tool 41 is passed out of sheath 12 (e.g. by pushing tube
handle 50 distally). This causes tube loops ends 22 to move
distally out of sheath end 16. Pushing wire loops 24 distally (e.g.
by pushing wire handle 52 distally) causes wire loop distal ends 28
to move distally out of windows 23, and increase the distance
between tube loop distal ends 22. This causes the combined
structure of tube loop distal ends 22 and wire loop distal ends to
widen and extend radially, opening aperture 5 of device 10 into its
deployed state.
[0118] The radial force of the deployed wire loops and tube loops
pushes them against the artery and by the combined motion of distal
pushing and rotation applied by the user, the wire loops dissect
between a plaque and arterial wall into the subintimal space. Their
position can be verified angiographically.
[0119] Dissection is continued until either the lesion is passed,
or the maximal deployment distance (distance D) is reached. The
physician can then pull wire handle 52 proximally, thus contracting
aperture 5 at the distal end of the device. If the lesion was
completely traversed and normal intima was reached, closure of
aperture 5 may easily detach the dissected lesion from the distal
intimal lining. If the closure is performed at mid lesion, greater
pull force or one or more of the cutting elements and techniques
described below may need to be utilized in order to cut through the
lesion.
[0120] Once the aperture 5 has been closed, the lesion may become
enclosed within tube loops 18 and optionally sac 80. It can then be
pulled back towards the entry site. If too large to remove via the
access sheath, the device with lesion in it may be extracted by
removal of the sheath first, or using minimal surgical cut-down.
Thus, the at least one tube loop can be configured to remove a
plaque from an arterial wall.
[0121] FIG. 2C is a perspective end view of deployed device 10.
[0122] More particularly, FIG. 2C is a perspective end view of a
device 10 with four sets of loops, in its deployed state. FIG. 2C
shows that the at least one tube loop can form a cross-section of
the device that has a generally circular shape. Sheath 12 is seen
at the center. Tube loops are seen exiting from sheath 12, ending
at tube loop distal ends 22, with windows 23, from which are seen
protruding wire loop distal ends 28.
[0123] The specific arrangement of wire loops and tube loops shown
in the embodiment in FIG. 2C is the same as will be described
herein in FIG. 4C. According to this arrangement, one wire loop
distal end 28a may pass above adjacent wire loop distal ends 28c,
and the opposite wire loop 28b may pass under adjacent wire loop
distal ends 28c. As seen in FIG. 2C, aperture 5 may be formed by
the combined structure of tube loop distal ends 22 and wire loop
distal ends 28, and may have a substantially circular cross
section.
[0124] Tube loop distal ends from which exit wire loop distal end
28a, are labeled tube loop distal ends 22a, while tube loop distal
ends from which exit wire loop distal end 28b, are labeled tube
loop distal ends 22b. Sac 80 may cover the loops.
[0125] FIG. 2D is a perspective end view device 10, closed beyond
dissected tissue. More particularly, FIG. 2D is a perspective end
view of a device 10 with four sets of loops, in its closed state
beyond dissected tissue. From periphery to center, are seen: sac
80, covering tube loops 18 and containing dissected tissue, tube
loop distal ends 28a-b, with windows 23, from which exit wire loop
distal ends 28a-c.
[0126] The specific arrangement of wire loops and tube loops shown
in the embodiment in FIG. 2D is the same as will be described
herein in FIG. 4C, and as shown in FIG. 2C. According to this
arrangement, one wire loop distal end 28a may pass above adjacent
wire loop distal ends 28c, and the opposite wire loop 28b, may pass
under adjacent wire loop distal ends 28c.
[0127] At the center of FIG. 2D are seen wire loops 28a-c, creating
a complete closure of aperture 5. Due to the specific arrangement
of wires and loops, wire loop distal end 28a may be slightly above
(i.e., distal to) two wire loop distal ends 28c, both of which may
be at the same level, whereas wire loop distal end 28a may be
slightly below (i.e., proximal to) wire loop distal ends 28c. Tube
loop distal ends 28a may accordingly by slightly above tube loop
distal ends 28b. Sac 80 may cover the loops and contain dissected
tissue.
[0128] FIG. 2E is a perspective view of the distal end of tool 41,
closed beyond dissected tissue. More particularly, FIG. 2E is a
perspective view of a device 10 with four sets of loops, in its
closed state beyond dissected tissue. Tube loop distal ends 22a may
be slightly above (i.e., distal to) tube loop distal ends 22b, with
wire loop distal end 28a exiting window 23 of tube loop distal ends
22a, wire loop distal end 28b exiting window 23 of tube loop distal
ends 22b. Wire loop distal end 28c may pass between window 23 of
tube loop distal ends 22a to window 23 of tube loop distal ends
22a.
[0129] Wire loops 28a-c, create a complete closure of aperture 5.
Due to the specific arrangement of wires and loops, wire loop
distal end 28a may be slightly above (i.e., distal to) two wire
loop distal ends 28c, both of which may be at the same level,
whereas wire loop distal end 28a may be slightly below (i.e.,
proximal to) wire loop distal ends 28c. Tube loop distal ends 28a
may accordingly by slightly above tube loop distal ends 28b.
[0130] FIG. 2F is a simplified schematic longitudinal cross section
through the end of tool 41 showing the scissoring action of the
wire loops. More particularly, FIG. 2F is a simplified schematic
longitudinal cross section through wire loop distal end 28c, in a
plain parallel to that created by the arch of wire loop distal end
28c. Wire loop distal end 28a may be above (distal to) wire loop
distal end 28c, and wire loop distal end 28b may be below (proximal
to) wire loop distal end 28c. Intima 2, or any other tissue, may be
seen trapped between wire distal loop ends 28.
[0131] As shown in FIG. 2F, during closure of aperture 5, each of
wire loop distal end 28a and 28b may typically move towards each
other and pass each other, scissoring intima 2.
[0132] Reference to the term "wire" is mentioned herein, which may
refer to any of wires, braided wires or cables, strips, or any
other elongate element, having any cross sectional shape, and made
of any material.
[0133] Reference to the term "tubes" may refer to any elongate
hollow element, having any cross sectional profile, and made of any
material. The tube loop can be an arch along a longitudinal axis of
the sheath in the deployed state. The at least one tube loop can
also be an arch having two legs along a longitudinal axis of the
sheath in the deployed state. The arch can have a curved
symmetrical structure spanning an opening. The arch can be
substantially homogeneous and/or seamless such that at least a
portion of the surface of the arch is an uninterrupted material.
For example, in some embodiments the arch can include a curved tube
of a uniform surface with the exception of a distal window.
[0134] The at least one wire loop 28 can be a monofilament wire of
shape memory material. A shape memory material used in wire loops
can be made of a nickel titanium alloy known as nitinol, which is
composed of about 55% Ni and 44% Ti, with trace elements of Cu (150
ppm), Fe (110 ppm), and Mn (21 ppm). As a shape memory material,
nitinol central wires can have the characteristic of
superelasticity whereby they exhibit a superelastic tendency to
retain the shape in which they are formed when heat is applied to a
suitable presorting temperature. This characteristic serves to
reinforce the orientation toward the configuration into which wire
loops constructed in this manner are bent. Thus, the at least one
wire loop can be a monofilament wire of shape memory material. The
at least one wire loop can be made of nitinol.
[0135] The use of the composite construction with a nitinol
material and surrounding stainless steel strands are also
contemplated within broad inventive principles disclosed herein.
The composite construction can allow for ease of construction in
that the surrounding stainless steel strands can easily be soldered
to each other at joints, whereas nitinol material is not nearly so
readily joinable. In addition to the improvements in efficiency of
construction and enhanced durability and reliability of operation,
the use of the described composite construction also provides a
savings in cost of material over the use of a single superelastic
material for the forming of elastic wires.
[0136] It is to be noted that, while specific examples of wire loop
composition have been disclosed herein, other configurations are
suitable which fall within the scope of this invention.
[0137] In an embodiment used for peripheral endarterectomy for the
lower limbs, sheath 12 may be preferably made of a flexible polymer
with relatively high axial strength such as PEBAX or PEEK etc.,
with an outer diameter of approximately 3.4 mm and a wall thickness
of 0.1 mm, and a length of approximately 120-160 cm. Atraumatic tip
17 may be made of a softer material as known in the art. Tube loops
14 may preferably be made of a resilient material such as a
stainless steel braid, e.g. HHS .RTM. tube from Fort Wayne metals,
having a small outer diameter of approximately 0.014'' and wall
thickness of approximately 0.0019''. Wires 24 may preferably be
resilient wires or cables such as nitinol, stainless steel etc.,
with an OD of approximately 0.0078''.
[0138] For peripheral endarterectomy of the lower limbs, distance D
may typically be 10-40 cm, preferably 20-30 cm.
[0139] For carotid endarterectomy, distance D may typically be 5-15
cm, preferably 8-12 cm.
[0140] For coronary endarterectomy, distance D may typically be
0.5-10 cm, preferably 1-3 cm. The device can be configured for the
minimally invasive removal of tissue in an endarterectomy.
[0141] Of note, windows 23 may have a length, which is typically
0.5-5 times the diameter of tube loops 18, preferably 0.8-3 times
this diameter. A smaller diameter might cause excessive friction
between wires, a larger diameter interferes with complete closure
of aperture 5.
[0142] Each window 23 may be a longitudinal slot as depicted in
FIGS. 1A and 1B, or may alternatively consist of two separate holes
or openings in tube loop distal end 22, in which case the window
length mentioned above would refer to the distance between these
openings.
[0143] Using tube loops 18 as part of the design is beneficial in
several ways, as opposed to using a separate tube for each leg of
wire loops 24.
[0144] First, the tube loops provide support for the combined
tube-wire structure which forms aperture 5. If tube loops are
disconnected into separate tubes, the structure loses its stability
and typically flattens out.
[0145] Second, during advancement of device 10 for dissection of
the plaque, tube loops act as springs, which store energy when
pushed from the proximal end, and then release it, propelling the
distal end of the device further along the lesion.
[0146] Third, the tubes themselves provide support to the excised
tissue during removal from the body. Loops create closer pairs of
tubes that provide better support.
[0147] FIGS. 3A-3H describe the stages of a procedure using device
10.
[0148] All of FIGS. 3A-3H are simplified schematic longitudinal
sections of a hollow body organ, in which device 10 is seen in side
view. In all these figures, wall 1 of hollow body organ is seen,
covered by an internal layer 2, and having lumen 3 blocked by
blockage 4. Guiding catheter 6 is seen at the proximal end of the
hollow body organ.
[0149] In the case that the described procedure is a percutaneous
remote endarterectomy, the hollow body organ may be an artery, wall
1 may consist of the media and adventitia of the artery, layer 2
may be the intimal layer, and blockage 4 may be an atherosclerotic
lesion.
[0150] More particularly, FIG. 3A shows the site of an intended
procedure just before insertion of device 10. A guiding catheter 6
is shown in lumen 3, proximal to blockage 4, optionally having been
placed under fluoroscopic guidance or using other imaging
modalities.
[0151] FIG. 3B shows the site of an intended procedure just after
insertion of device 10 through guiding catheter 6, including the
same features and components shown in FIG. 3A. In addition, sheath
12 of device 10 is seen protruding distally out of guiding catheter
6, proximal to blockage 4. Distal end 16 of sheath 12 is distal to
guiding catheter 6 and proximal to blockage 4.
[0152] Note that use of guiding catheter 6 is optional. Device 10
may be inserted over a wire, or even without either a wire or a
guiding catheter.
[0153] In FIG. 3B, device 10 is seen in its initial/basic state,
with tool 41 still inside sheath 12.
[0154] FIG. 3C shows the site of a procedure during passage of tool
41 out of sheath 12, including the same features and components
shown in FIG. 3B. In addition, tube loop distal ends 22 are seen
protruding distally out of sheath 12, still proximal to blockage
4.
[0155] In FIG. 3C, tool 41 is still crimped, i.e., tube loop distal
ends 22 are seen protruding out of sheath 12, however wire loop
ends 28 have not yet pushed out, and aperture 5 has not yet
expanded.
[0156] FIG. 3D shows the site of a procedure at the end of
deployment, including the same features and components shown in
FIG. 3B. In addition, tube loop distal ends 22 are seen protruding
distally out of sheath 12, and wire loop distal ends 28 are seen
protruding distally out of tube loop distal ends 22, still proximal
to blockage 4.
[0157] In FIG. 3D, device 10 is seen in its deployed state, tube
loop distal ends 22 are seen protruding out of sheath 12 and
radially expanded, wire loop ends 28 are seen protruding out of
tube loop distal ends 22 and radially expanded, and aperture 5 is
fully expanded, such that tube loop distal ends 22 and wire loop
distal ends 28 are in contact with wall 1.
[0158] FIG. 3E shows the site of a procedure following deployment
and during advancement of device 10, including the same features
and components shown in FIG. 3B. In addition, tube loop distal ends
22 are seen protruding distally out of sheath 12, and wire loop
distal ends 28 are seen protruding distally out of tube loop distal
ends 22, now passing between blockage 4 and wall 1. In an
endarterectomy procedure, loops would now be within the subintimal
space.
[0159] In FIG. 3E, device 10 is seen in its deployed state, tube
loop distal ends 22 are seen protruding out of sheath 12, radially
expanded, and passing along and around blockage 4. Wire loop ends
28 are seen protruding out of tube loop distal ends 22 and radially
expanded, being advanced distally by the user, and passing around
and along blockage 4.
[0160] FIG. 3F shows the site of a procedure following advancement
of device 10 beyond blockage 4, including the same features and
components shown in FIG. 3B. In addition, tube loops 18 are seen
protruding distally out of sheath 12, and wire loop distal ends 28
are seen protruding distally out of tube loop distal ends 22,
having passed between blockage 4 and wall 1.
[0161] In FIG. 3F, device 10 is seen still in its deployed state,
tube loops 18 are seen protruding out of sheath 12, radially
expanded, and having been advanced along and around blockage 4,
beyond its distal end. Wire loop distal ends 28 are seen protruding
out of tube loop distal ends 22 and radially expanded, and passing
around and along blockage 4, beyond its distal end.
[0162] FIG. 3F shows that device 10 has now traversed blockage
4.
[0163] FIG. 3G shows the site of a procedure following closure of
device 10 beyond blockage 4, including the same features and
components shown in FIG. 3B. In addition, tube loops 18 are seen
protruding distally out of sheath 12, expanding radially, passing
along blockage 4, and coalescing distal to it.
[0164] In FIG. 3G, device 10 is seen in its closed state, tube
loops 18 are seen protruding out of sheath 12, radially expanded,
and passing along and around blockage 4, then joining together
beyond its distal end. Wire loop distal ends 28 are not seen as
they were pulled back into tube loop distal ends 22 in order to
close aperture 5, which is now closed.
[0165] FIG. 3H shows the site of a procedure during removal of
device 10, including the same features and components shown in FIG.
3B. In addition, tube loops 18 are seen protruding distally out of
sheath 12, expanding radially, passing along blockage 4, and
coalescing distal to it.
[0166] In FIG. 3H, device 10 is seen in its closed state, tube
loops 18 are seen protruding out of sheath 12, radially expanded,
and passing along and around blockage 4, then joining together
beyond its distal end. Wire loop distal ends 28 are not seen as
they were pulled back into tube loop distal ends 22 in order to
close aperture 5, which is now closed.
[0167] In FIG. 3H, device 10 in its closed state containing
blockage 4 or any excised tissue is seen being pulled proximally.
Device 10 may subsequently be removed from the body through the
percutaneous entry site.
[0168] Not shown (for clarity) is sac 80, which can contain
blockage 4 by the end of the procedure. FIGS. 4A-4F are schematic
front views of device 10 showing various configurations of wires
and tubes in accordance with the current invention. In the
following description, the terms "clockwise" and
"counter-clockwise" refer to directions relative to the center of
FIG. 4A, for example, from a distal end perspective.
[0169] As can be seen from FIGS. 4A-4F, the at least one tube loop
18 can have a window 23 that allows for passage of the at least one
wire loop 28. In some embodiments, the window of the at least one
tube loop can be a distal window. That is, the tube loop can have
the window at the distal end of the tube loop. The at least one
tube loop can be hollow to surround the at least one wire loop in
the crimped state. The wire loop can be exit-able and/or extendible
from the at least one tube loop. A diameter of the at least one
wire loop can be less than an inner diameter of the at least one
tube loop. Typically the diameter of the at least one wire loop
will be in close fit to the inner diameter of the at least one tube
loop.
[0170] The window can have a longitudinal axis. The at least one
tube loop can have a longitudinal axis, and the distal window can
have a length along the longitudinal axis in a range between about
0.5 to about 5 times a diameter of the at least one tube loop. In
some embodiments, the distal window can have a length along the
longitudinal axis of a range between about 0.8 to about 3 times a
diameter of the tube loop.
[0171] More particularly, FIG. 4A is a schematic front view of the
tip of device 10 with four tube loops 18 having distal ends 22 and
windows 23, each tube loop 18 having a "clockwise" oriented leg 19
and a "counter-clockwise" oriented leg 21. As can be seen, the at
least one tube loop can include four spatially equidistant
loops.
[0172] Wire loop distal ends 28 are shown, each with a
"counter-clockwise" leg threaded through window 23 and leg 21 of
one tube loop 18, and a "clockwise" leg threaded through window 23
and leg 19 of another tube loop 18, located adjacent to previous
loop 18 in a clockwise direction.
[0173] Each "counter-clockwise" leg of wire loop distal end 28
passes below adjacent wire loop distal end 28 when entering leg 21,
and each "clockwise" leg of wire loop distal end 28 passes above
adjacent wire loop distal end 28 when entering leg 19, such that
each wire loop distal end 28 spans between the two most distant
legs 21 and 19 of two adjacent tube loops 18. Thus, each tube loop
can have a first and a second wire loop. From a distal end view in
the radial axis of the sheath, the second wire loop can extend
under the first wire loop in a clockwise direction of the radial
axis of the sheath. Thus, in this embodiment, each of a first set
of two opposing wire loops extends over one of a second set of
opposing wire loops that are adjacent to the first set. Further,
each of the second set of opposing wire loops can extend under one
of the first set of opposing wire loops in a radial axis of the
sheath.
[0174] FIG. 4B describes another preferred embodiment with a
different arrangement of wires.
[0175] More particularly, FIG. 4B is a schematic front view of the
tip of device 10 showing the same features as FIG. 4A, except that
in this embodiment, two opposing wire loop distal ends 28 pass only
above adjacent wire loop distal ends 28. Thus, in this embodiment
each of a first set of opposing wire loops extends over both of a
second set of opposing wire loops that are adjacent to the first
set. Further, each of the second set of opposing wire loops extends
under the first set of adjacent opposing wire loops in a radial
axis of the sheath.
[0176] FIG. 4C describes yet another embodiment with a different
arrangement of wires.
[0177] More particularly, FIG. 4C is a schematic front view of the
tip of device 10 showing the same features as FIG. 4A, except that
in this embodiment, one wire loop distal end 28 (marked a in FIG.
4C) passes only above adjacent wires, and the opposing wire loop
distal end 28 (marked b in FIG. 4C) passes only below adjacent wire
loop ends 28. In this embodiment, one wire loop can extend over
adjacent wire loops and an opposing wire loop can extend under
adjacent wire loops.
[0178] FIG. 4D describes yet another embodiment with a different
arrangement of wires.
[0179] More particularly, FIG. 4D is a schematic front view of the
tip of device 10 showing the same features as FIG. 4A, except that
in this embodiment, each wire loop distal end 28 passes to the side
of the catheter opposite from where it exits window 23, such that
when tube loops 18 are advanced into the blood vessel, each said
wire loop end 18 remains adjacent the opposite side of the vessel.
When the wires are pulled back, each wire passes across the center
line of the vessel, thus creating a scissoring action and ensuring
the intima is cut. In this embodiment the wires do not cross each
other (i.e. are not interlaced). Each wire loop can have a
pre-formed curvature around a radial axis of the sheath. The
curvature can be radially displaced from a longitudinal axis of the
sheath. At least one of the wire loops can extend over at least
another wire loop and at least one of the wire loops can extend
under at least another of the wire loops in the radial axis of the
sheath.
[0180] The wire loops can be moveable to a plurality of locations
with respect to a radial axis of the sheath. The wire loops can be
configured to contact each other. The wire loops can be configured
to close such that a scissor action between adjacent wires is
operable to cut intima of the tissue. In a radial axis of the
sheath, each wire loop can extend under another wire loop and over
another wire loop.
[0181] FIG. 4E describes yet another embodiment with a different
arrangement of wires.
[0182] More particularly, FIG. 4E is a schematic front view of the
tip of device 10 showing the same features as FIG. 4D, except that
in this embodiment, three of the wires are interlaced with adjacent
wires. Only the top (i.e. most distal) wire is above all others and
not interlaced with any of them. This enables the wires to pass the
center line of the vessel when they are pulled, creating a
scissoring action between adjacent wires, ensuring the intima is
cut. Thus, as can be seen from FIG. 4E, a first wire loop can
extend over all other wire loops and other wire loops can be
interlaced with adjacent wire loops in the radial axis of the
sheath. The first wire loop when retracted can be configured to
pass a center line of the body lumen. Each expandable loop can have
a first wire loop that extends in a counter-clockwise direction of
the radial axis of the sheath and a second wire loop that extends
in a clockwise direction of the radial axis of the sheath. As shown
in FIG. 4E, the first and second wire loops can cross each other in
the radial axis.
[0183] FIG. 4F describes yet another embodiment with a different
arrangement of wires.
[0184] More particularly, FIG. 4F is a schematic front view of the
tip of device 10 showing the same features as FIG. 4A, except that
in this embodiment, each wire loop distal end 28 has a
"counter-clockwise" leg threaded through window 23 and leg 19 of
one tube loop 18, and a "clockwise" free end threaded through
window 23 and leg 21 of another tube loop 18, located adjacent to
previous loop 18 in a clockwise direction. In this configuration
each wire loop end spans between the two closest legs 21 and 19 of
two adjacent tube loops 18, such that no wires cross one over the
other. In this embodiment, the first and second wire loops do not
cross each other in the radial axis.
[0185] In practice, this configuration tends to naturally flip into
a configuration similar to that in FIG. 4A, unless tube loop ends
22 are intentionally kept in this orientation, for example by a
multilumen tube or other techniques as further described below.
[0186] Various other wire and tube configurations are possible and
are included in the scope of this invention.
[0187] Although in the embodiments described above, all of wire
loops 24, or all of tube loops 18 are typically advanced together
as one, in other embodiments, each wire loop 24 or tube loop 18 can
be advanced individually. This may provide greater control over the
stages of separation of the plaque. Optionally, wires can be
operated in groups, e.g. one group comprising two wires having wire
loops distal ends 28 running in parallel, and the other group
comprising the two other wires having wire loops distal ends 28
perpendicular to them. Alternatively one group may comprise three
wires, while the other group comprises the fourth wire. Clearly,
many different combinations exist, especially if more than four
loops are used.
[0188] Although in the embodiments described above, wire loops 24
are typically advanced by advancing both proximal ends 26 of wire
loop 24, in other embodiments one proximal end 26 is kept fixed in
relation to sheath 12, while only the other proximal end 26 of the
same wire loop 24 is advanced, such that wire loop distal end 28 of
wire loop 24 is formed of a different segment of wire loop 24 at
each given moment. This may be achieved for example by one proximal
wire loop end 26 being attached to tube loop 18 a short distance
(e.g. 1-5 cm) proximal to tube loop distal end 22. An advantage is
that while in the previously described embodiments, the segment of
wire loop 24 forming the bend at wire loop distal end 28 might
apply relatively low radial force when opening aperture 5,
according to the current embodiment, a new, unbent segment of wire
is pushed distally to form wire loop distal end 28, and will
therefore have greater radial force.
[0189] FIG. 4G shows an embodiment in which window 23 consists of a
single elongate slot.
[0190] More particularly, FIG. 4G is a schematic cross section of
tube loop distal end 22 showing wire loops 24 passing through it
and exiting its distal end through window 23. Window 23 has a
length 1. Typically, wire loop distal ends 28 will exit tube loop
distal end 22 at the two lateral edges of window 23. Tube loop
distal end 22 has a diameter d.
[0191] FIG. 4H shows an embodiment in which window 23 consists of
two discrete holes or openings. Thus, the window 23 of the at least
one tube loop can be a distal window. That is, the window can be
disposed at a distal position of the tube loop. Further, the window
can outline two holes or openings. In this embodiment, the two
holes can house two wire loops, for example. More particularly,
FIG. 4H is a schematic cross section of tube loop distal end 22
showing wire loops 24 passing through it and exiting its distal end
through a window 23 consisting of two separate holes. In this
embodiment, 1 indicates the distance between the farthest ends of
the two holes. Tube loop distal end 22 has a diameter d.
[0192] Of note, these are schematic drawings, which do not depict
the exact relationship between components. Typically, the inner
diameter of tube loops 18 would closely match the outer diameter of
wires 24.
[0193] One of the goals of the current invention is to provide
means for cutting the tissue at the distal end of the dissected
lesion, as an integral part of the same percutaneous device used
for dissection around the lesion. FIGS. 5-6 describe examples of
such means.
[0194] In an embodiment shown in FIG. 5, the inner side (the side
far from the vessel wall) of at least one of windows 23 of tube
loop end 22 has a sharp edge or element 60, configured to cut
intima or plaque.
[0195] More particularly, FIG. 5 is a perspective view of tube loop
distal end 22 of device 10, showing two legs of wire loop distal
ends 28 exiting window 23. Sharp element 60 may consist of a
sharpened edge of window 23 of tube loop distal end 28. Typically,
element 60 is located at the lumen side of window 23, so it does
not contact the vessel wall.
[0196] Optionally, element 60 is capable of transitioning between a
sharp and blunt state, for example, by changing its orientation
relative to the longitudinal axis of tube loop distal ends 22. The
sharp and blunt state can also be a cutting and non-cutting state,
respectively. In an embodiment, this transition is achieved by the
tightening of wire loops 24 during closure of aperture 5 of device
10. When the user wishes to excise the lesion, wires 24 are pulled
back, bringing sharp element 60 in contact with the outer side of
the intima, and cutting it, even if it is thickened and hardened
due to disease.
[0197] Use of this embodiment is depicted in FIGS. 5B-5D.
[0198] FIG. 5B depicts the situation before beginning the cutting
stage, FIG. 5C is a "snapshot" of the situation during the cutting
stage, just before the transition of sharp elements 60 to their
sharp state, and FIG. 5D is a "snapshot" of the situation at the
moment of cutting the intima, just after sharp elements 60 have
transitioned to their sharp state. Thus, the at least one tube loop
can include a sharp element at the distal end. The distal end of
the at least one tube loop can include a blunt portion that is
oriented away from an arterial wall of the body lumen and can
include a sharp portion having the sharp element that protrudes
into the tissue to be removed.
[0199] A detailed explanation of the cutting process follows:
[0200] FIG. 5B is a simplified schematic longitudinal cross
section-side view of the tip of device 10 in its deployed state,
inside an artery at the distal end of an atherosclerotic lesion,
with sharp elements 60 in their blunt state. This Fig. depicts the
situation at the end of the procedure, just before cutting the end
of the lesion.
[0201] More particularly, arterial wall 1 is shown with its intimal
layer 2 and arterial lumen 3. Inside arterial lumen 3, the tip of
device 10 is seen comprising tube loop distal ends 22 shown with
the plane of section passing through their middle. Wire loop distal
ends 28 are seen protruding outwardly through windows 23, extending
radially and engaging arterial wall 1, thus dissecting within the
subintimal space, between arterial wall 1 and intimal layer 2, and
separating plaque 4 seen at a more proximal location inside device
10. For the sake of clarity, only two tube loop distal ends 22, and
two wire loop distal ends 28, are shown, although the device may
consist of any number of these.
[0202] Sharp elements 60 are seen at the luminal side of windows
23, coiled towards their lateral side. Sharp elements 60 do not
engage the arterial wall because they do not protrude beyond the
lateral edge of window 23, and also because wire loop distal ends
28 push arterial wall 1 outwardly. Thus sharp elements 60 do not
interfere with dissection.
[0203] FIG. 5C is a simplified schematic longitudinal cross
section--side view of the tip of device 10 in its semi-deployed
state (or during transition from its deployed state to its closed
state), inside an artery at the distal end of an atherosclerotic
lesion, with sharp elements 60 still in their blunt state. This
figure depicts the situation during beginning of closure of
aperture 5, just before cutting the end of the lesion.
[0204] More particularly, arterial wall 1 is shown with its intimal
layer 2 and arterial lumen 3. Inside arterial lumen 3, the tip of
device 10 is seen comprising tube loop distal ends 22 shown with
the plane of section passing through their middle. Wire loop distal
ends 28 are seen protruding outwardly through windows 23, engaging
arterial wall 1 but not pushing it radially.
[0205] At this stage, wire loop distal ends 28 were drawn
proximally just enough to not protrude radially beyond tube loop
distal ends 22, and the device was advanced slightly distally, so
that points S, where intimal layer 2 separates from arterial wall 1
are as close as possible to sharp elements 60. This is done in
order to minimize the length of any intimal flap that might be
created.
[0206] For the sake of clarity, only two tube loop distal ends 22,
and two wire loop distal ends 28, are shown, although the device
may consist of any number of these.
[0207] Sharp elements 60 are seen at the luminal side of windows
23, coiled towards their lateral side. Sharp elements 60 do not
engage the arterial wall because they do not protrude beyond the
lateral edge of window 23.
[0208] FIG. 5D is a simplified schematic longitudinal cross
section--side view of the tip of device 10 in its almost closed
state (or towards the end of transition from its deployed state to
its closed state), inside an artery at the distal end of an
atherosclerotic lesion, with sharp elements 60 now in their sharp
state. This figure depicts the situation during closure of aperture
5, just at the moment of cutting the end of the lesion.
[0209] More particularly, arterial wall 1 is shown with its intimal
layer 2 and arterial lumen 3. Inside arterial lumen 3, the tip of
device 10 is seen comprising tube loop distal ends 22 shown with
the plane of section passing through their middle. Wire loop distal
ends 28 are seen exiting through windows 23, pulling tube loop
distal ends 22 towards each other. At this stage, wire loop distal
ends 28 were drawn further proximally, applying tension between
tube loop distal ends 22, and applying force on sharp elements 60',
which have now transitioned to their sharp state facing the luminal
side and have cut intimal layer 2.
[0210] For the sake of clarity, only two tube loop distal ends 22,
and two wire loop distal ends 28, are shown, although the device
may consist of any number of these.
[0211] Sharp elements 60 are seen at the luminal side of windows
23, now facing the luminal side.
[0212] Note that arterial wall 1 is depicted kinked at the cutting
point. This kink may occur temporarily during the cutting stage due
to the inward forces applied by the loops and sharp elements which
pull the intima and arterial wall, but may resolve immediately once
the intima has been cut.
[0213] In another embodiment, the inner edge of wire loop distal
ends 28 is made sharp, thus enhancing cutting capability.
[0214] In another embodiment shown in FIGS. 6A-6D, a cutting
element is positioned around the tip of device 10 so that at the
end of the procedure it is ideally located to cut the tissue at a
point beyond the dissected lesion.
[0215] Cutting element 70 may be a thin but durable wire, a strip
which is at least slightly sharp in the area of wire loop distal
ends 28, or any element configured for cutting tissue such as a
resistor which heats upon transfer of electrical current through
it, an optic fiber delivering laser light, or any other appropriate
cutting elements as known in the art.
[0216] FIGS. 6A-6D describe the cutting process using cutting
element 70. For the sake of clarity, only three tube loop distal
ends 22 and wire loop distal ends 28 are shown, the artery is not
shown, and in FIGS. 6A, 6C, and 6D, wire loop distal ends 28 are
not shown. Also for the sake of clarity, the cutting stage is
depicted as if occurring very close to sheath 12, whereas in
practice this is typically done at a significant distance from the
sheath.
[0217] FIG. 6A is a 3D depiction of the tip of device 10 in its
crimped state. Thus, the device can further include a cutting
element that is located at the distal end of the at least one tube
loop. The cutting element can be configured to expand radially with
expansion of the aperture, as shown in FIG. 6B. The cutting element
can surround the aperture of the tool.
[0218] FIG. 6B is a 3D depiction of the tip of device 10 in its
deployed state.
[0219] More particularly, distal end 16 of sheath 12 of device 10
is seen, from which protrude distally and radially tube loops 18
and from them protrude wire loop distal ends 28, forming aperture
5.
[0220] Cutting element 70 is shown passing along sheath 12 and
around tube loops distal ends 22, where it slidably passes through
at least one permanent connector 72 and at least one detachable
connector 71, said connectors typically attached to tube loops
distal ends 22. Alternatively, said connectors may be attached to
wire loop ends 28.
[0221] As evident from FIG. 6A, cutting element 70 expands radially
with expansion of aperture 5, and is thus located at the leading
edge of tube loops distal ends 22, surrounding any tissue dissected
free from the artery by wire loops distal ends 28.
[0222] FIG. 6C is a 3D depiction of the tip of device 10 in its
closed state around the tissue at the distal end of a lesion.
[0223] More particularly, tube loops 18 are seen protruding
distally out of sheath 12, and converging around tissue 100 which
may be an intimal layer, an atherosclerotic plaque, or a different
type of tissue if used for other applications.
[0224] Cutting element 70 is shown passing along sheath 12 and
around tube loops distal ends 22, where it slidably passes through
permanent connector 72 and detachable connectors 71. Not shown in
this figure are wire loop distal ends 28 which also surround and
constrict tissue 100.
[0225] The user now optionally activates cutting element 70, and
pulls it proximally, causing it to be released from detachable
connectors 71 and cut through tissue 100.
[0226] FIG. 6D is a 3D depiction of the tip of device 10 in its
closed state at the distal end of a lesion, after cutting element
70 has cut the tissue.
[0227] More particularly, tube loops 18 are seen protruding
distally out of sheath 12, and converging around tissue 100.
[0228] Cutting element 70 is shown passing along sheath 12 and
through permanent connector 72. It was released from detachable
connectors 71, and cut through tissue 100. Not shown in this figure
are wire loop distal ends 28 which also surround and constrict
tissue 100.
[0229] In use, when device 10 is deployed, cutting element 70
slides through connectors 71 and 72 and opens as a loop around tube
loops distal ends 22 (FIG. 6B). As it is thin, and does not
protrude significantly to any side, cutting element 70 does not
interfere with plaque separation.
[0230] Once separation of plaque is complete, wire loops 24 are
pulled proximally by the user, causing tube loop ends 22 and wire
loop ends 28 to tightly constrict around tissue 100 (FIG. 6C).
Cutting element 70 is also pulled slightly proximally, such that it
tightly encircles tissue 100.
[0231] As shown in FIG. 6D, cutting element 70 is then activated
(by pulling it proximally if it is a wire, by "shifting" the
leading segment to a sharp segment if it is a strip as described
below, by transferring electrical current or a different energy
form if it is an insulator, optic fiber or other means of energy
transfer). Typically, cutting element 70 is then pulled proximally,
slides through permanent connectors 72, and cuts detachable
connectors 71 and tissue 100. FIG. 6D shows device 10 around a
piece of tissue 100 after cutting element 70 was pulled proximally
and cut the tissue around tube distal ends 22. Thus, the cutting
element can include a blunt and a sharp state. In some embodiments,
the cutting element can include a cutting and a non-cutting state.
Further, the cutting element can be configured to transition
between blunt and sharp states upon the aperture substantially
closing.
[0232] Controlling the radial force at the aperture 5 adds
versatility to use of device 10. Embodiments enabling control of
the radial force, in either a predetermined, or an adjustable
manner, are described in FIGS. 7A and 7B.
[0233] In an embodiment shown in FIG. 7A, tube loop distal ends 22
have an outwardly oriented curve at an angle .alpha.. This serves
to increase the radial force applied to the arterial wall by the
combined structure formed by tube loop distal ends 22 and wire loop
distal ends 28. The greater the outward angle .alpha., the greater
the radial force.
[0234] More particularly, FIG. 7A is a schematic side view of the
working end of device 10. For the sake of clarity only two sets of
tube and wire loops are shown. Tube loops 18 are seen with wire
loop distal ends 28 protruding therefrom. Angle .alpha. is the
angle between the straight part of tube loop 18 and the outwardly
curved part, tube loop distal end 22.
[0235] In an embodiment, wire loops 24 additionally, or only, have
a similar curve to that described above.
[0236] In an embodiment, any of the above outward curves may be
achieved by heat treatment of the tube and/or wire material.
[0237] In another embodiment, a segment of the tube is replaced or
covered by a more rigid tube with the outwardly curved shape. In
yet another embodiment, at least one wire is connected to tube loop
distal ends 22, allowing control of the curvature, such that the
curve can be increased by pulling this wire proximally.
[0238] In an embodiment depicted in FIG. 7B, control of radial
force is achieved by replacing, or "shifting" the segment of wire
comprising wire loop distal end 28 (by pushing one side distally
and pulling the other proximally), using wire loops 24 that have
several segments with different levels of rigidity, shape or
curvature, and optionally varying sharpness. The segment of wire
loop 24 located at wire loop distal end 28 confers the desired
rigidity to the distal end of device 10 and determines its radial
force. Thus, the tool in the deployed state can have a radial force
and the tool can be configured to allow adjustment of at least one
of the radial force and the aperture. The at least one tube loop
can have an adjustable outward angle and the adjustment of the
radial force can take place by pushing the wire loop along a
longitudinal axis of sheath. Further, the at least one wire loop
can have varying degrees of rigidity/flexibility and the adjustment
of the radial force can be by shifting a location of segments of
the at least one wire loop.
[0239] Low rigidity and high flexibility are useful in the crimped
state. Increasing degrees of rigidity can confer increasing radial
force to the deployed device.
[0240] In an embodiment, one of the above segments may have a sharp
inner edge, and may be brought to the leading end of the loop only
when cutting of the end of the plaque is desired.
[0241] A control, which may for example consist of a rotating
button on handle 40, may allow shifting of the wire segment
comprising wire loop distal end 28, and thus determining the
characteristics of aperture 5.
[0242] More particularly, FIG. 7B is a schematic side view of the
working end of device 10 and handle 40. For the sake of clarity
only two sets of tube and wire loops are shown. Tube loops 18 are
seen with wire loop distal ends 28 protruding therefrom.
[0243] Wire loop proximal ends 26 are seen entering handle 40 and
connecting to a rotating control button 76. In the current example
button 76 has three positions each corresponding to the analogous
segment on wire loop 24. Rotating button 76 to any of the
positions, brings the corresponding wire segment to be at wire loop
distal end. Optionally, one such button 76 controls all wire loops
24. Alternatively, each wire loop 24 is controlled separately.
[0244] In an embodiment shown in FIG. 8, a "compartment/sac" is
used to contain the dissected plaque in order to remove it as a
whole and prevent debris from falling off during removal. Such
"compartment/sac" may for example consist of a thin sleeve made of
polyurethane, silicone, latex, or any other thin membrane, a fine
wire mesh, a fabric such as Gortex, etc.
[0245] More particularly, FIG. 8 is a schematic longitudinal
section--side view of a guiding catheter 6, through which was
passed the distal part of device 10 showing sheath 12 with tube
loops 18 extending distally out of its distal end 16, and wire loop
ends 28 protruding therefrom, creating aperture 5. Again for the
sake of clarity, only two sets of loops and wires are shown. Sheath
12 may be slideably disposed within guiding catheter 6. A ring 86
may be slideably disposed between guiding catheter 6 and sheath 12.
Sac 80, having distal end 82 and proximal end 84 may be slideably
disposed over sheath 12, with its proximal end 84 connected to ring
86, and its distal end 82 connected at least at one point to tube
loop distal ends 22. In another embodiment, sac 80 may be attached
to tube loops 18 from ends 22 to proximal ends 20 and may have
sufficient slack in it to allow for radial expansion of the loops
and containment of large plaques or other excised tissue.
[0246] In yet another embodiment, sac 80 may be connected in at
least one point to wire loop distal ends 28.
[0247] Sac 80 may further include a thickened or fortified rim at
its distal end 82. This is typically a slightly thicker ring of the
sac, made of the same material as the rest of the sac. For example,
if the sac is made of 0.01 mm polyurethane, the rim may be created
by folding sac 80 back and welding it to itself, so its thickness
is .about.0.02 mm. The rim may provide several advantages:
[0248] First, such fortified rim can serve as, or include, a
connection element aiding in connection of sac 80 to wire loop
distal ends 28.
[0249] Second, this fortified rim may cause sac 80 distal end 82 to
assume a circular cross sectional shape when aperture 5 opens,
instead of being stretched into assuming a polygonal cross section,
which could interfere with its ability to follow the path of
dissection taken by wire loop ends 28.
[0250] Returning to the embodiment shown in FIG. 8, sac 80 can
advance along sheath 12 as tube loops 18 are pushed distally out of
sheath 12. As it advances, the sac can surround and contain the
tissue dissected away from the artery by wire loop ends 28 and tube
loop ends 22. At the end of dissection, after the cutting stage,
the distal end 82 of sac 80 closes with the closure of aperture 5,
and the complete excised specimen may be removed as one, within sac
80.
[0251] Thus, as shown in FIG. 8, the device can include a sac 80 at
least a portion of which is either disposed inside the sheath 12 or
at least a portion of which is disposed outside a portion of the
sheath 12. The sac is configured to enclose the at least one tube
loop 18 and at least one wire loop 28 in the closed state. The sac
80 can be connected to at least one portion of the distal end 28 of
the tube loop 18. The tool 41 can also include a ring 86 that is
slideably disposed between the multilumen tube 30 and the sheath
12. The sac 80 can be connected to the ring 86. The sac can be
connected to at least one portion of the distal end of the at least
one tube loop.
[0252] In an embodiment shown in FIG. 9, device 10 has a
construction similar to that previously described in FIGS. 1-4, and
in addition comprises an additional level of tube loops.
[0253] More particularly, FIG. 9 is a three dimensional depiction
of the distal working end of device 10, showing only three sets of
each level of loops, for the sake of clarity. From proximal to
distal shown are the distal end of sheath 12, tube loops 18
protruding distally therefrom, having tube loops distal ends 22 and
windows 23. Protruding from windows 23 are wire loops 24 ending
with wire loop distal ends 28, however in this embodiment, these
elements are made of hollow tubes or sheaths instead of wires, and
have additional windows 113 at sheathwire loop distal ends 28.
Slideably disposed within these tubes 124 are wire loops 110 having
wire loop distal ends 112 protruding out of windows 113 in a manner
similar to that described above for wire loop distal ends 28,
windows 23, and tube loop distal ends 22.
[0254] The above configuration may be repeated many times with
additional levels of tubes. This construction may provide greater
versatility with a possibility of advancing each set of loops to
different distances, and better control of device behavior in
different areas, for example by widening the device to different
diameters at different locations.
[0255] In general, the most distal level, consisting of wire loops
may be used for dissection, whereas the more proximal levels
consisting of tube loops may be pushed distally in an alternating
fashion, which improves their ability to advance around the
tissue.
[0256] Controlling this action manually may provide delicate haptic
feedback to the physician, who can feel changes in resistance as
the loops are advanced.
[0257] In an embodiment, an engine could be used to advance the
various levels of loops by alternating motions, or by
vibration.
[0258] Thus, the at least one tube loop and the at least one wire
loop can include three levels of loops. For example, the tool can
include a first level of at least one tube loop and a second level
of at least one tube loop that proceeds from a distal end of the
first level of the at least one tube loop in the deployed state.
Further, the at least one wire loop can extend from the distal end
of the second level of the at least one tube loop in the deployed
state.
[0259] FIG. 10 shows device 10', which is generally similar to
device 10 previously described in FIGS. 1A and 1B, with various
modifications.
[0260] More particularly, FIG. 10 is a schematic longitudinal
section of a preferred embodiment of device 10 in its crimped
state, mainly comprising the following parts, from proximal to
distal: handle 40', cables 120 and 130, tube connector 121 and wire
connector 131, one or more tube loops 18 and one or more wire loops
24, which may be slideably disposed within a sheath 12 having
proximal end 14 and distal end 16, short multilumen segment 140
also slideably disposed within sheath 12, sac 80, and optionally an
atraumatic tip 17.
[0261] In this embodiment, tube cable 120 may have a distal end
connected to tube connector 121 which may be slideably disposed
within sheath 12, and a proximal end fixedly connected to elongate
casing 42. Tube loops 18 may all be connected to tube connector 121
at their proximal end 20.
[0262] Sheath 12 may be slideably disposed within elongate casing
42, and can be withdrawn proximally by a tube handle 51, to expose
tube loops 18.
[0263] Wire cable 130 may have a distal end connected to wire
connector 131 which is slideably disposed within sheath 12, and a
proximal end connected to wire handle 52. Wire loops 24 may all be
connected to wire connector 131 at their proximal end 26'. Thus,
pushing wire handle 52 distally, may deploy wire loop distal ends
28 and open aperture 5.
[0264] Wire handle 52 may protrude outwardly of casing 42 through
slot 47. Since in the current embodiment, handle 52 does not move
together with tube handle 50 as in the embodiment shown in FIG. 1,
slot 47 does not need to be long as did slot 46.
[0265] Short multilumen segment 140 (a few millimeters long) may
optionally be placed proximal to the distal end 16 of sheath 12,
such that tube loops 18 pass through its peripheral lumens 145,
maintaining an organized configuration of the tubes.
[0266] Sac 80 can be stored within sheath 12, folded in the gap
between distal end 16 and the short multilumen segment 140. Short
multilumen segment 140 can be pushed distally out of sheath 12 up
almost its whole length. Alternatively, short multilumen segment
140 may be fixedly connected to the interior of sheath 12.Thus, the
device can further include a multilumen segment that is configured
to house a portion of the at least one tube loop. The device can
further include connections between each of adjacent tube loops.
The connections can be distal to the multilumen segment.
[0267] An advantage of this design is that wire handle 52 does not
move relative to casing 42 during advancement of tube loops 18.
[0268] Another advantage of this design is that tube cable 120 and
wire cable 121 can be relatively thick and rigid yet flexible
wires, which are more resistant to buckling than long segments of
thin wire and tubes as in FIG. 1A, and are cheaper than multiple
thin wires, tubes, or multilumen catheter.
[0269] It should be noted that in this embodiment, advancement of
deployed wire loops 24 and tube loops 18 around the plaque may be
performed by moving the whole device handle 40 distally, which
increases the treating physician's ability to collect tactile
information from the device and control the procedure.
[0270] Adding control and accuracy to the opening and closing of
aperture 5 can be done by adding a threaded button 53 to handle 40.
As shown in FIG. 10, threaded button 53 may be slideably positioned
over elongate casing 42, having an inner thread, and may have a
slot for receiving handles 52. Elongate casing 42 may have an
external thread along slot 47. This construction allows exact
control of the deployment of wire loops 24 by rotating threaded
button 53, which may move wire connector 33 axially without
rotating it.
[0271] Another advantage of using this type of control is that it
allows application of tensile forces to wire loops 24, which are
typically made of nitinol and therefore are capable of great
elongation. This may necessitate pulling wire connector 33
proximally beyond its original position, for complete closure of
aperture 5, especially if closing it over tissue with a large
diameter or having tough consistency. To facilitate this, the
initial position of wire handle 52 in the crimped state of device
10 before use may not be at the proximal end of slot 47 and its
external thread, rather, there may be sufficient range of movement
to either side along slot 47, so as to allow for the compensation
for wire loop 24 elongation.
[0272] When high axial stresses are encountered by the leading edge
of the device (wire loop distal ends 28), there may sometimes be a
tendency of the more proximal tube loops 18 to buckle and collapse.
This buckling can occur within sheath 12, or distal to it.
[0273] Several ways of preventing this are described:
[0274] Prevention of tube loop buckling within sheath 12 can be
achieved for example by gradual reinforcement of tube loops 18
towards their proximal end. Such reinforcement can be done by
increasing tube wall thickness, adding a layer of braid, adding a
coating, using more rigid wires in the HHS braid, etc.
[0275] Another way of preventing buckling within sheath 12
comprises reducing the available space around the tubes. This can
be done either by minimizing the inner diameter of the sheath, or
by adding a central core, or tube, that will support tube loops 18,
such that they are compressed between it and the sheath.
[0276] Using an inflatable balloon instead of said core or tube,
may enable temporarily splinting tube loops 18 to the inner side of
sheath 12. Such splinting may also be beneficial for increasing the
torquability of the device. For example, if the user wishes to
rotate the working end of the device, inflating said balloon may
increase transfer of torque to wire loop distal ends 28, so that
they may rotate with rotation of handle 40.
[0277] A similar method of supporting tube loops 18 can be used
outside sheath 12, once the tubes have exited it and are within the
vessel lumen. Inflating an elongate balloon in the vessel just
distal to sheath distal end 16 may provide support to the tubes and
reduce their tendency to buckle.
[0278] Another problem that may occur with construction of the
device of the invention relates to correct opening of aperture
5.
[0279] If wire loops 24 and/or tube loops 18 are coiled at a
relatively small radius along their longitudinal axis, they may
tend to swivel to the same orientation around the long axis of the
device. If this occurs, when opening aperture 5, the structure
formed may not be an open aperture, rather it may be collapsed,
having a cross section shaped as a concave polygon.
[0280] Preventing this can be done by ensuring that the elongate
elements (wires, tubes, sheath) of the device are straight, or at
least have a large diameter of curvature--e.g. approximately 100 cm
diameter of curvature for a device with a 10 french (3.3 mm) outer
diameter. This may require keeping the device in an elongate or
large diameter packaging.
[0281] A modification mentioned previously--adding the short
multilumen segment 140 proximal to sheath distal end 16, can
maintain correct orientation and order of tube loops 18 and thus
assist in preventing this issue.
[0282] Another possible solution is including a directional feature
on tube loops 18 that forces them to maintain the correct
orientation.
[0283] FIG. 11 describes an example of this embodiment.
[0284] More particularly, FIG. 11 is a simplified schematic cross
sectional view of device 10' at the middle of short multilumen
segment 140, showing only two sets of tubes, for the sake of
clarity. From the periphery to the center of the figure are seen
sheath 12, short multilumen segment 140 slideably disposed therein,
said segment 140 having peripheral lumens 141 and central lumen
142. Peripheral lumens 141 may have an oval cross sectional shape.
Slideably disposed within peripheral lumens 141 are tube loops 18',
which may have an oval cross sectional shape too, corresponding to
that of peripheral lumens 141. Slideably disposed within tube loops
18' are wire loops 24.
[0285] The oval cross sectional shapes of tube loops 18' and
peripheral lumens 141 serve as directional features which may
ensure that the order and orientation of tube loop distal ends 22
are maintained at they pass distal end 16 of sheath 12, thereby
ensuring correct opening of aperture 5.
[0286] To create the oval cross sectional shape, tubes 18 may be
processed, for example by being compressed along at least a part of
their length so as to change their cross section from circular to
oval.
[0287] Other directional features that can be used instead of the
oval cross section include but are not limited to square, oblong,
triangular, crescent, and u shaped cross sections, as well as
longitudinal directional features. Thus, the tool can include a
directional feature that ensures order and orientation of the at
least one tube loop. A directional feature can include the tube
loop having a portion with an oval cross-sectional shape and a
central lumen of the multilumen segment having an oval
cross-sectional shape.
[0288] Another way to prevent the problem of the aperture opening
flatly is depicted in FIGS. 12A and 12B--that is, by adding
connections between each two adjacent tube loop ends, just distal
to short multilumen segment 140. The combination of this connection
between the tube loops, with passing the loops proximally through
the multilumen, ensures the orientation of the loops will be kept,
and chances of buckling can be significantly reduced.
[0289] FIG. 12A is a schematic 3D depiction of the distal of tube
loops 18 in an almost crimped state of the device.
[0290] More particularly, short multilumen segment 140 is seen,
through which may pass multiple tube loops 18, ending as tube loop
distal ends 22. Connections 160 are seen joining each two adjacent
tube loops 18, distal to short multilumen segment 140. Sheath 12 is
not shown, for clarity. Typically, short multilumen segment 140 is
positioned within sheath 12, a few centimeters proximal to its
distal end 16. Also not show are windows 23, and wire loop distal
ends 28.
[0291] FIG. 12B is a schematic 3D depiction of the distal of tube
loops 18 in an almost deployed state of the device.
[0292] More particularly, multiple tube loops 18 are seen, ending
as tube loop distal ends 22. Connections 160 are seen joining each
two adjacent tube loops 18.
[0293] Short multilumen segment 140, sheath 12, windows 23, and
wire loop distal ends 28 are not shown, for clarity.
[0294] Connections 160 may typically be made by laser welding tube
loops 18, adhesion, or any other method as known in the art.
[0295] Connections 160 reinforce the structure created by tube
loops 18, and when combined with short multilumen segment 140, this
structure becomes even stronger.
[0296] Connections 160 do not interfere with passage of loops 18
through short multilumen segment 140, as they are distal to it.
[0297] Another possible way of solving this issue may be creating a
weak adhesion between tube loops 18, such that they form one
elongate structure. Such a structure may be more resistant to
buckling, but may be easily separated from its distal end, when
aperture 5 is opened by pushing wire loops 24 distally. A drawback
of this method is that it may only work for a single
deployment.
[0298] The above embodiments assume that during use of device 10,
in its deployed state, the radial force applied by wire loop distal
ends 28 against the arterial wall combined with distal pushing and
rotation applied by the user, the wire loops will dissect between
the plaque and arterial wall into the subintimal space. In some
embodiments, the radial force of the wire loops and tube loops,
together with pushing forward and some rotation, can result in the
wire loops going into the path of least resistance, in the case of
an atherosclerotic plaque, into the subintimal space.
[0299] The following embodiments are intended to facilitate this
process.
[0300] FIG. 13 depicts an embodiment having a graded wire loop
distal ends structure to improve entry of device 10 into the SIS.
Thus, the at least one wire loop can be graded in the deployed
state. The graded wire loops can protrude from the distal end of
the sheath at varying distances. The at least one wire loop can
have a graded distance between a most distal wire loop distal end
and a most proximal wire loop distal end. The graded distance can
provide improved entry of the tool to the subintimal space.
[0301] More particularly, FIG. 13 is a 3D depiction of distal end
of device 10, showing sheath 12, with four tube loops 18 protruding
from sheath distal end 16. Wire loop distal ends 150 to 153 exit
tube loop distal ends 22 through windows 23, each protruding
gradually less distally than the wire loop distal end next to it,
such that wire loop distal end 150 may be the most distal, and wire
loop distal end 153 may be the most proximal, thus creating a
spiral formation.
[0302] In use, wire loop distal end 150 may be the first to enter
the subintimal space, and each adjacent loop may follow as the
device is advanced and rotated in the direction of arrow f.
[0303] To further improve entry into the SIS, a guidewire window
155 is provided at wire loop distal end 150, which in this case may
be made of a hollow tube or sheath.
[0304] In use, optionally, a guidewire may first be inserted into
the SIS under angiography as known in the art, and subsequently
device 10 may be inserted over the guidewire by passing the
guidewire into window 155 and all the way through device 10. This
may ensure that wire loop distal end 150 easily enters the SIS.
[0305] Although described in the context of percutaneous remote
endarterectomy, the devices of the invention may also be used and
are intended for use for various other medical applications,
including but not limited to the following:
[0306] Blood clot removal:
[0307] In situations where a blood clot clogs an artery or vein,
there is a need for a minimally invasive technique for removal of
such clot. This need is especially important in acute massive
pulmonary embolism, which is a severe, life threatening condition
due to hemodynamic compromise. Thus, the device can be configured
for the minimally invasive removal of tissue in a pulmonary
embolism.
[0308] Whereas various atherectomy devices have been used in an
attempt to treat pulmonary embolism, these devices are not ideally
suited for clot removal.
[0309] As described in the article: "Catheter-assisted pulmonary
embolectomy.", Sobieszczyk P, Circulation. 2012 Oct.
9;126(15):1917-22.
[0310] "The disadvantage of endovascular therapies lies in the size
mismatch between the caliber of the proximal pulmonary arteries and
the size of endovascular devices designed for thrombus removal from
much smaller coronary or peripheral vessels or dialysis fistulas.
In addition, to be accessible to catheter assisted embolectomy, the
pulmonary embolism has to be located in the main pulmonary arteries
or in the proximal segmental branches."
[0311] Thus, the device of embodiments of the invention can be
configured for the minimally invasive removal of tissue in an
embolectomy or thrombectomy.
[0312] The device of the invention is capable of removing and
containing fresh clot trapped in the pulmonary arteries or their
branches. In addition, it may also be used for removing older clot,
which typically becomes similar to atherosclerotic lesions. Use of
the device of the invention in these cases is similar to its use
for endarterectomy, as described above.
[0313] Urinary stone removal:
[0314] Devices for removing urinary calculi are often designed as
baskets. One of the drawbacks of some of these devices is that the
stones might fall between the struts of the baskets. The device of
the invention solves this issue by encasing the stone from all
sides by the tube loops 18 as well as by the sac 80. Thus, the
device can be configured for the minimally invasive removal of
tissue in a urolithotomy procedure.
[0315] Other applications:
[0316] The device of the invention may additionally be used for
removal of bezoars from the GI tract, removal of foreign bodies
from the bronchial tree or from any other body lumen.
[0317] Thus, methods of use and embodiments of the present
invention can be directed to a method for minimally invasively
removing tissue from a body lumen, which includes: passing a tool
through a sheath that is configured to transition from a crimped
state to a deployed state and to a closed state, a distal end of
the tool having at least one tube loop and at least one wire loop;
forming an aperture at a distal end of the tool in the deployed
state; and dissecting tissue in the deployed state.
[0318] The method can be such that the forming the aperture
includes extending the wire loops. The extending the at least one
wire loop can include advancing the at least one wire loops through
at least one window of the at least one tube loop. The passing the
tool through the sheath can include transitioning to an expanded
state. In some embodiments, passing the tool does not transition
the tool into the expanded state until the wire loops are
pushed.
[0319] The tissue can be a lesion and the method can further
include extending the tool along the lesion. The dissecting can
include dissecting the lesion along a longitudinal axis of the body
lumen.
[0320] The method can further include closing the aperture distal
to the dissected tissue to contain the tissue; and removing the
tissue in the closed state.
[0321] The tool can include a handle at a proximal portion of the
sheath; and a multilumen tube disposed inside at least a portion of
the sheath, the multilumen tube being configured to interface with
the at least one tube loop, and the method can further include
passing the tool through the distal end of the sheath using
movement of the handle.
[0322] The handle can include an elongate casing having a wire
handle connected to the at least one wire loop and a slot for the
wire handle to slide. The multilumen tube can be disposed inside at
least a portion of the casing. The method can further include
enclosing the loops with a sac in the closed state.
[0323] The method can further include passing the at least one wire
loop through windows of the at least one tube loop in the deployed
state.
[0324] The method can further include utilizing a cutting element
to remove the tissue. The method can further include inserting a
wire loop into the subintimal space of the tissue; and threading a
leading wire loop distal end over a wire which has been inserted
into the subintimal space of the tissue.
[0325] The method can further include: housing at least a portion
of the at least one tube loop with a multilumen segment; and
providing connections between each of adjacent tube loops distal to
the multilumen segment.
[0326] The at least one tube loop can have a graded distance of the
distal ends for the tool's improved entry to the subintimal space
of the tissue.
[0327] The minimally invasive removal of tissue can include an
endarterectomy. The minimally invasive removal of tissue can
include an embolectomy. The minimally invasive removal of tissue
can treat a pulmonary embolism. The minimally invasive removal of
tissue can include a percutaneous procedure. The minimally invasive
removal of tissue can include a urolithotomy.
[0328] The cutting element can be further defined as follows:
[0329] A cutting element, comprising:
[0330] a wire that is configured to extend around a distal portion
of a tool configured to pass through a sheath and configured to
transition from a crimped state to a deployed state and to a closed
state, the distal portion of the tool forming an aperture;
[0331] a plurality of connectors that is configured to receive the
wire,
[0332] wherein at least one of the plurality of connectors is a
permanent connector and at least one of the plurality of connectors
is a detachable connector, and
[0333] wherein when tension is exerted to the wire, the at least
one permanent connector is configured to pass the wire to radially
constrict the wire, and the at least one detachable connector is
configured to release the wire, wherein the wire is operable to cut
tissue inside the aperture.
[0334] While various exemplary embodiments have been described
above, it should be understood that they have been presented by way
of example only, and not limitation. Thus, the breadth and scope of
the present disclosure should not be limited by any of the
above-described exemplary embodiments, but should instead be
defined only in accordance with the following claims and their
equivalents.
* * * * *