U.S. patent application number 13/369969 was filed with the patent office on 2012-08-16 for material removal catheter and method.
Invention is credited to J. Christopher Flaherty, Motoya Hayase.
Application Number | 20120209173 13/369969 |
Document ID | / |
Family ID | 40810433 |
Filed Date | 2012-08-16 |
United States Patent
Application |
20120209173 |
Kind Code |
A1 |
Hayase; Motoya ; et
al. |
August 16, 2012 |
MATERIAL REMOVAL CATHETER AND METHOD
Abstract
A catheter device and methods useable to extract material from a
body conduit, e.g., a blood vessel, are provided. The catheter
comprises a flexible catheter advanceable into the body conduit, an
opening in a wall of the catheter in fluid communication with a
material collection chamber, and a controllably arcuate segment
near the distal tip of the catheter and the opening. The catheter
may include a sliding member, located within a lumen of the
catheter, used to move the material entering the catheter through
the arcuate segment opening, into the material collection chamber
and away from said opening. The catheter may include a single
mechanism utilized to both generate a vacuum to cause material to
enter the catheter at the arcuate segment opening and also cause
the sliding member to travel, inside the catheter, moving material
away from the opening and into the material collection chamber.
Inventors: |
Hayase; Motoya; (Boston,
MA) ; Flaherty; J. Christopher; (Auburndale,
FL) |
Family ID: |
40810433 |
Appl. No.: |
13/369969 |
Filed: |
February 9, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12246995 |
Oct 7, 2008 |
8133214 |
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13369969 |
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10615122 |
Jul 8, 2003 |
7449010 |
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12246995 |
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60396042 |
Jul 15, 2002 |
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Current U.S.
Class: |
604/93.01 |
Current CPC
Class: |
A61M 25/0108 20130101;
A61M 25/0069 20130101; A61M 25/0054 20130101; A61B 17/22 20130101;
A61M 2025/0063 20130101; A61M 25/0155 20130101; A61B 2017/22079
20130101 |
Class at
Publication: |
604/93.01 |
International
Class: |
A61M 25/00 20060101
A61M025/00 |
Claims
1. A catheter for insertion into a biological conduit, comprising:
an elongate catheter shaft having a proximal end and a distal end;
a material collection chamber located within the catheter shaft
distal end; a controllably arcuate segment of the distal end of the
catheter shaft configured to selectively transition between a
straight configuration and a curved configuration, without
substantially altering a cross-section of the controllably arcuate
segment, the controllably arcuate segment including at least one
opening that creates a fluid path between the material collection
chamber and an exterior portion of the catheter shaft.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation application of U.S.
patent application Ser. No. 12/246,995, filed Oct. 7, 2008, which
is a continuation of U.S. patent application Ser. No. 10/615,122,
filed Jul. 8, 2003, now U.S. Pat. No. 7,449,010, issued Nov. 11,
2008, which relies for priority upon U.S. Provisional Patent
Application Ser. No. 60/396,042, filed Jul. 15, 2002, now expired,
entitled MATERIAL REMOVAL CATHETER AND METHOD.
FIELD OF THE INVENTION
[0002] The present invention relates generally to medical devices,
systems and methods and more particularly to a material removal
catheter and methods that are useable to remove thrombus and other
undesired material from the vasculature or other internal conduit
of a patient, the apparatus being particularly well suited for
saphenous vein grafts, coronary arteries and the peripheral
vasculature.
BACKGROUND OF THE INVENTION
[0003] Human blood vessels often become partly or fully occluded by
various undesired materials including plaque, thrombi or other
substances that restrict the flow of blood within the vessel.
Depending on the location of the occlusion, serious injury or even
death can occur. When diagnosed, it is often advantageous to remove
the occlusive material in a safe and effective manner. Coronary
heart disease is an extremely common form of this occlusive
disease, and is the leading cause of death in the United
States.
[0004] Arteriosclerosis is a chronic disease characterized by
abnormal thickening and hardening of the arterial walls. As the
coronary arteries are first narrowed by plaque, at locations known
as stenoses, further constriction may be caused by the formation of
blood clots, or thrombi, on the rough surface of the plaque. A
severe complication of arteriosclerosis is a myocardial infarction,
or MI. An MI is the death of a section of heart muscle when its
blood supply is cut off, usually by a blood clot in a coronary
artery narrowed by arteriosclerosis. An MI can occur spontaneously
due to severely narrowed vasculature or due to an embolus, such as
a thrombus released from an upstream stenosis. An embolus can even
be caused in a medical procedure intended to reduce or remove a
stenosis.
[0005] Various types of interventional techniques have been
developed that can be utilized to reduce or remove a blockage in a
blood vessel. One technique, known as balloon angioplasty, involves
using a special catheter that includes a balloon near its distal
tip, advancing the balloon into the constricted area, and inflating
the balloon to expand the constriction. Other therapeutic options
include atherectomy, deployment of stents, infusion of therapeutic
medications and heart bypass surgery. All of these therapeutic
options involve the risk of dislodging a portion of the occlusive
material, causing embolus to move downstream thus causing further
complications.
[0006] Heart bypass surgery is an extremely invasive and traumatic
form of therapy to treat coronary occlusive disease. In one form of
bypass, a portion of vein taken from the patient's leg, the
saphenous vein, is connected between the aorta and a portion of the
blocked artery distal to the blockage, supplying oxygenated blood
to the portions of heart muscle supplied by the artery prior to its
being occluded. These saphenous vein grafts often used in heart
bypass procedures are also susceptible to occlusive disease, and
over time may become restricted by plaque and thrombus.
Atherosclerotic plaque in saphenous vein grafts tends to be softer
and more friable than their arterial counterparts and thus more
prone to embolizing during treatment.
[0007] Chemical thrombolytic drugs are available to treat saphenous
vein grafts but require the patient to be non-ambulatory throughout
their use and have numerous risks and complications. Balloon
angioplasty of saphenous vein grafts is associated with a higher
rate of embolus generation, potentially migrating downstream to
block a portion of the coronary artery to which it is attached and
causing a myocardial infarction. Directional Coronary Atherectomy,
or DCA catheters include cutting blades that can damage the vessel
wall and the systems have a propensity to become clogged and
generate embolus similar to balloon angioplasty. Adjunctive devices
are available to reduce the complications of embolization by
trapping the released emboli downstream. These devices are
expensive, and complicated to use. Vacuum extraction catheters have
been developed to treat saphenous vein grafts, however they tend to
be large and bulky and have had sub optimal results and numerous
complications.
[0008] Clearly, therefore, there is a need for improved devices,
systems and methods for removal of undesired material from an
internal body conduit such as a saphenous vein graft or coronary
artery that improve the efficiency of material removal and reduce
the risks to the patient.
SUMMARY OF THE INVENTION
[0009] The present invention is directed to a device and method
that simply and effectively removes undesired material from the
wall of a conduit, such as a blood vessel. The device is a catheter
with an elongate catheter shaft having a proximal end and a distal
end. The distal end of the catheter shaft has a diameter less than
the conduit containing the undesired material, said catheter shaft
including a controllably arcuate portion or segment which can be
directed toward and make contact with the undesired material prior
to extraction. The controllably arcuate segment includes one or
more openings into which the material is drawn by applying a
negative pressure, or suction from the inside of the opening. The
controllably arcuate segment can be transformed into both a
relatively straight and a relatively bowed geometry with operator
controls contained on the proximal end of the catheter device.
[0010] The catheter device of the present invention may be inserted
into various body conduits including but not limited to blood
vessels such as coronary vessels, peripheral vessels, coronary
bypass grafts and arteriovenous fistulas. The device may be used
for diagnostic applications, such as taking a material sample, or
therapeutic applications such as reducing an occlusion within a
saphenous vein graft. The device can be used in various hospital
and outpatient settings, and can be guided using fluoroscopy and
other imaging technologies. The device may include various markers
or other visualization elements, such as radiopaque fillings or
bands, ultrasound crystals or ultrasonic markers, or other markers
or indicators to aid in positioning and use of the device. Such
markers may include rotational orientation markers to indicate the
position of one or more openings in the controllably arcuate
segment. In addition or alternatively, the catheter device may
include an arcuate condition indicator providing visual or other
feedback to the operator as to the relatively straight or
relatively bowed geometric conditions of the controllably arcuate
segment. In a preferred embodiment, an audio signal is provided,
such as when the controllably arcuate segment is in the relatively
bowed geometry, to prevent the clinician from inadvertently
advancing or otherwise moving the catheter shaft when the
controllably arcuate segment should be in a relatively straight
geometry. In another preferred embodiment, the catheter device
includes a lumen, included along a minority or a majority of the
length of the catheter shaft, through which a guidewire can be
inserted for practice of over the wire interventional
techniques.
[0011] The openings in the controllably arcuate segment of the
device are in fluid communication with one or more ports or
chambers in the proximal, external portion of the device via one or
more lumens. Within or at the end of the lumens may exist one or
more valves oriented to permit flow of material in one direction
only. Located in a distal portion of the catheter, near to and in
fluid communication with the openings is a material collection
chamber. The material collection chamber is proximal or distal to
the openings, and is in fluid communication with the proximal,
aspirating portion of the device via a connecting lumen. In a
preferred embodiment, the material collection chamber is the
connecting lumen itself. Suction applied to the aspiration portion
is communicated to the openings in the controllably arcuate segment
via the material collection chamber.
[0012] In a preferred embodiment, the aspiration chamber may be
connected to a waste exit, such as by a one-way valve such that
when positive pressure is applied, material collected in the
aspiration chamber from the openings in the controllably arcuate
segment is evacuated from the aspiration chamber.
[0013] In a preferred embodiment, within a lumen of the catheter
shaft is a sliding member that is connected to a mechanical linkage
extending through the catheter shaft to the proximal portion of the
device. The linkage is connected to sliding or other controls on
the handle of the catheter device for advancement and retraction of
the sliding member. In a preferred embodiment, the sliding member
and mechanical linkage include a lumen permitting a guidewire to be
placed through each. The linkage system may include one or more
mechanical stops that limit the advancement or retraction. In the
fully advanced position, the tip of the sliding member, which
preferably is tapered, extends beyond the distal end of the
catheter. The tip of the sliding member may extend beyond the end
of the catheter in the fully retracted position as well. The
sliding member can be used to change the geometry of the
controllably arcuate segment. In a preferred embodiment, the
controllably arcuate segment is normally bowed, and placing the
sliding member within the lumen of the controllably arcuate segment
changes the segment into a relatively straight geometry. To
facilitate the change in shape of the controllably arcuate segment,
the sliding member is constructed to be less flexible than the
controllably arcuate segment. The sliding member, which may have a
sharpened end that is oriented toward the opening, is advanced or
retracted to move toward the opening thereby cutting and or pushing
material away from the opening and into the material collection
chamber. The one or more openings can have different cross
sectional profiles, such as round or oval perimeters, or various
angles of tapers, and may change geometry based on the geometry of
the controllably arcuate segment and or the position of the sliding
member. The material collection chamber may be located proximal or
distal to the opening of the controllably arcuate segment, whereby
the sliding member is retracted or advanced respectively to move
the material received through the opening into the material
collection chamber. In order to draw material from the outside of
the catheter shaft through the opening in the controllably arcuate
segment, a negative pressure or suction is applied at an opening on
the proximal end of the catheter device. Aspiration or negative
pressure may be maintained during the period of time that the
sliding member is advanced or retracted. The present invention
includes various means of providing the suction including
connections to attach to syringes or sophisticated vacuum and
material collection generators as well as integrated aspiration
systems. The present invention may include one or more valves to
prevent blood leakage, avoid over pressurization, allow one way
flow of fluid and other material into or out of various chambers or
other locations and other purposes.
[0014] In another preferred embodiment, the controllably arcuate
segment has a normally bowed bias which is converted to a
relatively straight geometric shape by integral straightening
means. The normally bowed bias can be created during manufacturing
with catheter shaping processes known to those of skill in the art,
or with embedded curved stiffeners. The sliding member can function
as the integral straightening means, as is described above, or an
embedded element can change the controllably arcuate segment from a
relatively bowed to a relatively straight geometry, on command, via
controls located on the proximal portion of the device. In another
preferred embodiment, the controllably arcuate segment has a
normally straight bias which is converted to a relatively bowed
geometric shape by integral curving means. Various curving means
are described including mechanical pull wires or embedded curving
elements that are attached, such as via electrical wires, to
control means located on the handle on the proximal end of the
device. An embedded battery and a switch located on the handle are
used to connect the curving elements to a power source driving the
shape change of the curving element. Multiple states, or
transitional geometric shapes may be formed in the controllably
arcuate segment in addition to a maximally straight and a maximally
bowed geometry. Curving elements may be constructed of shaped
memory components, such as shaped memory alloys or shaped memory
polymers, piezo material, or electromagnet assemblies. Curving
elements may have a filament shape, a tubular shape or a
non-uniform shape. Curving elements may consist of single or
multiple components that cause the controllably arcuate segment of
the catheter shaft to transform to the proper bowed geometry, thus
positioning the controllably arcuate segment's opening up against
the wall of the body conduit into which the catheter device of the
present invention is inserted. Curving or straightening elements
may work in combination with a sliding member to change the
geometry of the controllably arcuate segment. Changing curvature of
the controllably arcuate segment can cause the openings in the
segment to change shape including changing from a fluidly closed to
a fluidly open state.
[0015] In a preferred embodiment, the proximal end of the catheter
device includes a handle with an integrated plunger assembly.
Retraction of a grasper moves a syringe like shaft and plunger to
create a negative pressure at the opening in the controllably
arcuate segment. In addition, continued retraction continues the
aspirating pressures causing material to be drawn through one or
more lumens in the catheter device to a chamber in the handle.
Advancement of the grasper causes material to evacuate the chamber
through a waste exit. In this particular embodiment, the grasper
may also advance or withdraw a mechanical linkage connected to a
sliding member which is used to sever or otherwise move material
away from the opening in the controllably arcuate segment.
[0016] In a preferred embodiment, the catheter device includes a
thru lumen from the proximal handle to the distal tip, such that
material, such as thrombus, can be aspirated from the handle
through the catheter shaft and removed from a location where the
distal end of the catheter resides. Alternatively, a core assembly,
such as an assembly including the mechanical linkage and sliding
member, is removable wherein removal of the core creates the lumen
that can be used to aspirate material from the distal end of the
catheter. In another preferred embodiment, the catheter device
includes a lumen for injecting fluids, such as radiopaque dye or
blood thinning agents, wherein the lumen is attached to an input
port on the handle of a the device and an exit located at or near
the distal end of the catheter device. The lumen can also be used
to extract material from the distal end of the catheter.
[0017] In another preferred embodiment, the catheter device
includes an elongate catheter body with a proximal end and a distal
end, an aspiration chamber located near the proximal end, a
controllably arcuate segment including at least one opening, and an
aspiration lumen in fluid communication with the aspiration chamber
and one or more openings in the controllably arcuate segment. The
device may include a sliding member to move material drawn through
the opening under pressure, away from the opening. The device may
have a normally bowed or a normally straight bias. The device may
further include one or more curving elements, controllable from the
proximal end of the catheter device, for transforming the
controllably arcuate segment from one geometric shape to
another.
[0018] A preferred method of using any of the catheter embodiments
of the present invention is also disclosed. The method for removing
material from a biological conduit includes providing a catheter
device having an elongate catheter shaft having a proximal end and
a distal end, a controllably arcuate segment including at least one
opening in fluid communication with the proximal end and a sliding
member that moves material received through the arcuate segment
opening away from said opening. The device is percutaneously or
surgically advanced into a biological conduit, preferably with the
controllably arcuate segment in a relatively straight geometry,
after which suction is applied to cause negative pressure at the
one or more openings. The sliding member is then retracted to move
material away from the opening. The controllably arcuate segment is
changed to a relatively straight geometry prior to advancing,
retracting or rotating the catheter device. In another preferred
method, after the catheter device is used to first extract
material, it is rotated and additional material is removed, each
rotation accompanied by a predecessor step of changing to a
relatively straight geometry, and each extraction step accompanied
by a predecessor step of changing to a relatively bowed
geometry.
[0019] Another preferred method is disclosed for removing material
from a biological conduit comprising the steps of providing a
catheter device having an elongate catheter shaft having a proximal
end and a distal end, a controllably arcuate segment including at
least one opening in fluid communication with the proximal end,
percutaneously or surgically inserting and transluminally advancing
the catheter into the biological conduit, applying suction to the
at least one opening in the controllably arcuate segment and
changing the shape of the controllably arcuate segment from a
relatively bowed geometry to a relatively straight geometry.
Additional steps may include changing from a relatively bowed to a
relatively straight geometry prior to insertion of the catheter
device. The device may be changed from a relatively straight
geometry to a relatively bowed geometry prior to applying suction.
Additional steps may include use of radiopaque markers to position
the device within the body conduit.
[0020] The present invention, therefore, provides a catheter device
for removing undesirable material, such as thrombus, from a body
conduit, such as a saphenous vein graft or other blood vessel,
including a controllably arcuate segment which further includes an
opening that can be brought in contact with the undesired material
with sufficient force such than under suction, the material is
drawn through the opening into an lumen, cavity or chamber within
the catheter device. The use of the device is simple and
straightforward, and does not require bulky or expensive equipment
not otherwise included in the various hospital settings in which it
will be used.
[0021] These aspects of the invention together with additional
features and advantages thereof may best be understood by reference
to the following detailed descriptions and examples taken in
connection with the accompanying illustrated drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1A is a side view of a first exemplary embodiment of a
catheter device constructed in accordance with the present
invention showing a controllably arcuate segment in a relatively
straight geometry.
[0023] FIG. 1B is a side view of the device of FIG. 1A showing the
controllably arcuate segment in a relatively bowed geometry.
[0024] FIG. 2 is a cross-sectional view of the device of FIGS. 1A
and 1B showing the opening in the controllably arcuate segment
positioned at a site in a biological conduit prior to removal of
occlusive material.
[0025] FIG. 3 is a cross-sectional view of a preferred embodiment
of a catheter device constructed in accordance with the present
invention.
[0026] FIG. 3A is an enlarged sectional view of the proximal end of
the catheter device contained in circle 3A of FIG. 3.
[0027] FIG. 3B is an enlarged sectional view of a distal end of the
catheter device contained in circle 3B of FIG. 3.
[0028] FIG. 4 is a cross-sectional view of the catheter device of
FIG. 3 shown with a grasper of the handle assembly in a retracted
position.
[0029] FIG. 4A is an enlarged sectional view of the proximal end of
the catheter device contained in circle 4A of FIG. 4.
[0030] FIG. 4B is an enlarged sectional view of the distal end of
the catheter device contained in circle 4B of FIG. 4.
[0031] FIG. 5 is a cross-sectional view of another preferred
embodiment of a catheter device constructed in accordance with the
present invention.
[0032] FIG. 5A is an enlarged sectional view of the proximal end of
the catheter device of FIG. 5 shown with the grasper of the handle
assembly shown in a fully advanced position.
[0033] FIG. 5B is an enlarged sectional view of the proximal end of
the catheter device of FIG. 5 shown with the grasper of the handle
assembly shown in a partially retracted position.
[0034] FIG. 5C is an enlarged sectional view of the distal end of
the catheter device of FIG. 5 shown with the sliding member in the
partially retracted position corresponding to the grasper position
of FIG. 5B.
[0035] FIG. 5D is an enlarged sectional view of the proximal end of
the catheter device of FIG. 5 shown with the grasper of the handle
assembly shown in a fully retracted position.
[0036] FIG. 5E is an enlarged sectional view of the distal end of
the catheter device of FIG. 5 shown with the sliding member in the
fully retracted position corresponding to the grasper position of
FIG. 5D.
[0037] FIG. 5F is an enlarged sectional view of the proximal end of
the catheter device of FIG. 5 shown with the grasper of the handle
assembly shown in a partially advanced position.
[0038] FIG. 5G is an enlarged sectional view of the distal end of
the catheter device of FIG. 5 shown with the sliding member in the
a partially advanced position corresponding to the grasper position
of FIG. 5F.
[0039] FIG. 6 is a cross-sectional view of another preferred
embodiment of a catheter device constructed in accordance with the
present invention.
[0040] FIG. 6A is an enlarged sectional view of the distal end of
the catheter device of FIG. 6 shown with the controllably arcuate
segment in a relatively straight geometric shape.
[0041] FIG. 6B is an enlarged sectional view of the distal end of
the catheter device of FIG. 6 shown with the controllably arcuate
segment in a relatively bowed geometric shape.
[0042] FIG. 7 is an enlarged sectional view of the distal end of
another preferred embodiment of the catheter device of the present
invention.
[0043] FIG. 8 is an enlarged sectional view taken along line A-A of
FIG. 7 showing a preferred configuration of a curving element.
[0044] FIG. 9 is an enlarged sectional view taken along line A-A of
FIG. 7 showing another preferred configuration of a curving
element.
[0045] FIG. 10 is an enlarged sectional view taken along line A-A
of FIG. 7 showing yet another preferred configuration of a curving
element.
[0046] Like reference characters designate identical or
corresponding components and units throughout the several
views.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0047] Referring first to FIGS. 1A and 1B, there is illustrated an
exemplary embodiment of a catheter device 10 constructed in
accordance with the present invention. The catheter device 10
includes a catheter shaft 20 constructed of materials that are
biocompatible and also permit flexibility of the device required to
allow insertion into and advancement through the vasculature of a
patient. Catheter shaft 20 contains one or more hollow lumens
within its structure that allow flow of material such as blood or
thrombus, as well as permit controlling shafts, mechanical linkages
or flexible tubes or wires to slide back and forth. Fixedly
attached to the proximal end of catheter shaft 20 is a handle,
handle 70, which allows the user to advance and maintain the
position of the distal end of catheter device 10, as well as rotate
the catheter shaft 20.
[0048] Handle 20 includes aspiration port 75 that is in fluid
communication with an internal lumen of catheter shaft 20.
Aspiration port 75 can be connected to various means of creating a
vacuum or suction, such as a vacuum generator or simple syringe.
Aspiration port 75 may include standardized threads, such as
standard luer threads, or other mechanical connection means to
facilitate connection to the suction means, not shown. Aspiration
port 75 is in fluid communication with a hollow lumen of catheter
shaft 20 via a similar lumen, opening or cavity within handle 70,
all not shown, but described in detail in subsequent figures.
Exiting handle 70 is a mechanical linkage, linkage 30 which
terminates at its proximal end with a separate handle for the user
to grasp, grasper 60. Advancement and retraction of grasper 60
causes similar linear motion of linkage 30 that is slidingly
received through the handle 70 and into catheter shaft 20.
[0049] Attached to the distal end of linkage 30 is a cylindrical
element, sliding member 100. Preferably, both linkage 30 and
sliding member 100 contain a thru lumen such that a standard
interventional guidewire can be inserted therethrough, and catheter
device 10 advanced and retracted over the guidewire using standard
interventional over the wire techniques. The combined lengths of
linkage 30 and sliding member 100 are preferably chosen such that
when grasper 60 is in both a fully advanced and a fully retracted
position, the distal tip of sliding member 100 exits the distal end
of catheter shaft 20. Preferably, the distal end of sliding member
100 is tapered to allow atraumatic advancement of catheter device
10 through the vasculature or other body conduits.
[0050] Near the distal end of catheter shaft 20 is controllably
arcuate segment 40, a finite length of shaft 20, proximal to the
tip of catheter device 10, that can be controlled by the user to
transform on command from a relatively straight geometry or shape,
to a relatively bowed, or arcuate geometry. Included at or near the
mid-portion of controllably arcuate segment 40 is a hole, opening
50, which traverses from the outer surface of shaft 20 to an
internal cavity contained within shaft 20. Referring specifically
to FIG. 1A, grasper 60 and sliding member 100 are shown in a
retracted position, and the controllably arcuate segment 40 is
shown in a relatively straight geometry. Referring now to FIG. 1B,
grasper 60 and sliding member 100 are shown in a fully advanced
position, and the controllably arcuate segment 40 is shown in a
relatively bowed geometry. There are various means of achieving
control of the shape of controllably arcuate segment 40 including
embodiments in which the controllably arcuate segment 40 is
normally bowed and means are provided for transforming to a
relatively straight geometry, as well as embodiments in which the
controllably arcuate segment 40 is normally straight, and means are
provided for transforming to a relatively bowed geometry. Numerous
means of controlling the shape of controllably arcuate segment 40
for FIGS. 1A and 1B as well as additional figures are described in
detail herebelow.
[0051] FIGS. 1A and 1B depict a preferred embodiment in which a
controllably arcuate segment 40 is simply a portion of catheter
shaft 20 that has been formed or shaped in its manufacturing
process to have a relatively bowed geometry. A common process for
catheter shaping includes inserting a pre-shaped metal mandrel in
the catheter during manufacture, and heating the device with the
mandrel in place. The mandrel length and shape geometry would be
designed to cause the proper bow at the proper location along the
catheter shaft 20. After a cooling time, the mandrel is removed and
the catheter assumes the desired shape. This process is often used
to form complex catheter tip shapes common to various
cardiovascular guide catheters, and is an effective way of shaping
an elastomeric tube with one or more internal lumens. In FIGS. 1A
and 1B, the sliding member 100 acts as the means of transforming
the normally bowed controllably arcuate segment 40 from its
manufactured bowed geometry to a relatively straight geometry. When
the sliding member 100 is advanced beyond the length of the
controllably arcuate segment 40, controllably arcuate segment 40
assumes its bowed configuration established during the
manufacturing process. The material selection, thickness and other
geometric parameters of sliding member 100 are chosen such that
when grasper 60 is retracted, linkage 30 retracts sliding member
100 accordingly, causing a significant length of sliding member 100
to reside within the internal lumen of controllably arcuate segment
40, further causing controllably arcuate segment 40 to transform
into a relatively straight geometry. When the grasper 60 and
attached linkage 30 are advanced, the majority of length of sliding
member 100 slides out of the internal lumen of controllably arcuate
segment 40, allowing it to reassume its bowed geometry. Subsequent
advancement and retraction of grasper 60, correspondingly advances
and retracts linkage 30 and sliding member 100 such that
controllably arcuate segment 40 transforms to a relatively bowed
geometry to a relatively straight geometry respectively.
[0052] Referring again to FIGS. 1A and 1B, there is included near
the midpoint of controllably arcuate segment 40 an hole, opening
50, which extends from the outer surface of catheter shaft 20 to an
inner lumen. As described above, aspiration port 75 is in fluid
communication with an internal lumen of catheter shaft 20, this
particular lumen also in fluid communication with opening 50 such
that when a vacuum is applied to aspiration port 75 by way of a
syringe or other means, suction is applied at opening 50 causing
material in close proximity to opening 50 to be drawn into the
lumen of shaft 20 via opening 50. Controllably arcuate segment 40
construction materials and geometry and the geometry of opening 50
may be chosen such that when controllably arcuate segment 40 is in
its relatively bowed geometry, opening 50 is relatively open,
however when controllably arcuate segment 40 is in its relatively
straight geometry, opening 50 is relatively closed.
[0053] Referring now to FIG. 2, a preferred method of utilizing
catheter device 10 is depicted. The catheter device 10 of the
present invention can be placed percutaneously or intraoperatively,
and advanced through a body conduit such as the vascular system. In
a preferred embodiment, catheter device 10 is inserted
percutaneously into the vasculature to treat a blood vessel, such
as a coronary vessel or saphenous vein graft placed during coronary
artery bypass graft surgery. Typically a guide catheter, not shown,
is placed at a convenient vascular access point such as a femoral
artery, and advanced to a point proximal to a stenotic location
such as the ostium of an occluded saphenous vein graft. Typically a
guidewire, such as an 0.014 inch guidewire, guidewire 300, is
advanced through the guide catheter and into the lumen of the
vessel to be treated to a location past the stenosis.
[0054] Next the catheter device 10 of the present invention is
percutaneously inserted and transluminally advanced through the
guide catheter and over guidewire 300 into the vessel to be
treated, blood vessel 200, positioning the opening 50 of the
controllably arcuate segment 40 near the area of occlusive material
to be removed, occlusive material 210. Each time the catheter
device 10 is inserted with the controllably arcuate segment 40 in
the relatively straight geometric condition, shown in FIG. 2 at a
later step with the controllably arcuate segment 40 in the
relatively bowed geometry. The operator would assure and or change
to that relatively straight geometry condition not only prior to
insertion, but each time the device is transluminally advanced,
withdrawn or rotated. In this particular embodiment, the catheter
device of FIGS. 1A and 1B, the operator would simply retract
grasper 60 to cause the controllably arcuate segment 40 to be in
the relatively straight geometric shape. Other means for changing
the shape of controllably arcuate segment 40 are described with the
subsequent figures below. Catheter shaft 20 has a length
appropriately chosen such that a small portion of the proximal end
of catheter shaft 20 extends out of the guide catheter, placing
handle 70 in close proximity to the insertion site, when opening 50
is properly positioned at the location of the occlusive material
210.
[0055] The axial position of the guide catheter, guidewire 300 and
various components of catheter device 10 are known within the
vessel utilizing conventional techniques and equipment which may
include, for example, fluoroscopy, ultrasound, nuclear magnetic
resonance imaging (NMR), and other visualization techniques and
equipment commonly found in hospital operating rooms,
catheterization laboratories and other therapeutic and diagnostic
environments. In a preferred embodiment, catheter shaft 20 can be
visualized with visualization equipment such as fluoroscopy, or
catheter shaft 20 has been modified to be visualized. Insertion of
radiopaque agents, such as barium sulfate, in small amounts, allows
relatively thin catheter shafts to be visualized with x-ray
equipment such as fluoroscopy. Various surface modification or air
bubble impregnation techniques can be employed to make the
implantable materials be visualized with ultrasound and other
modifications can be accomplished to be compatible with other
visualization technologies. Catheter shaft 20 and controllably
arcuate segment 40 shall be modified such that the user can
differentiate when the controllably arcuate segment 40 is in its
relatively straight geometry versus its relatively bowed geometry.
In a preferred embodiment, a visualization marker, marker 51,
preferably a radiopaque band, is also included near or surrounding
opening 50 such that during rotation of catheter shaft 20, the
angular orientation as well as the longitudinal positioning of
opening 50 can be visualized. Additionally, the catheter device 10
may include an internal lumen or pathway, not shown, that allows
angiographic dye to be injected into it, exiting at a point at or
near the distal tip of catheter shaft 20, such as through the
guidewire lumen, around the guidewire lumen, or through opening
50.
[0056] Referring still to FIG. 2, the catheter device 10 has been
transluminally advanced over guidewire 300 such that opening 50 has
been positioned near the occlusive material 210. Note that at this
point in the procedure, controllably arcuate segment 40 remains in
the relatively straight geometry, not depicted in FIG. 2, that it
has maintained through the entire insertion process thus far. At
this time, the operator transforms the controllably arcuate segment
40 from the relatively straight geometry to the relatively bowed
geometry depicted in FIG. 2. With the particular embodiment of
FIGS. 1A and 1B, the operator would simply advance the grasper 60
to its fully advanced position. The outside diameter of catheter
shaft 20 is chosen to be somewhat less than the inner diameter of
the vessels it is advanced through, including the vessel diameter
at the stenosis. The radius of curvature and length of controllably
arcuate segment 40 in its maximally bowed geometric shape is chosen
such that opening 50 is pushed against the occlusive material with
some amount of force. Catheter device 10 will be manufactured with
not only various lengths and diameter profiles, but numerous radii
of curvature and segment lengths for controllably arcuate segment
40, to accommodate a range of body conduits to be treated,
specifically blood vessels such as saphenous vein grafts. Catheter
diameters, lengths and other geometric criteria are chosen based on
the path from the percutaneous entry site to the treatment site, as
well as the size and geometry of the vessel to be treated and the
size and geometry of the occlusive material to be removed. In its
maximally bowed geometry depicted in FIG. 2, the opening 50 of
controllably arcuate segment 40 is positioned such that as suction
is applied via aspiration port 75, occlusive material 210 is drawn
into an internal cavity of catheter shaft 20. In a preferred
embodiment, controllably arcuate segment 40 at the general area of
opening 50 would place a small amount of force against the
occlusive material when the controllably arcuate segment 40 is in
its relatively bowed geometric shape.
[0057] A next step for the operator is to retract grasper 60
causing linkage 30 and thus sliding member 100 to also retract. As
sliding member 100 retracts, its proximal end pushes, potentially
cutting, material projecting through opening 50 to a location away
from the opening, more proximal to the aspiration port 75. Vacuum
or suction may be maintained during the retraction of sliding
member 100. Optionally, grasper 60 can be advanced again, advancing
linkage 30 and sliding member 100 causing controllably arcuate
segment 40 to change from a relatively straight geometry to a
relatively bowed geometry and positioning opening 50 again against
any remaining occlusive material 210. Suction can be reapplied, and
grasper 60 again retracted, once again moving any material
protruding through opening 50 away from opening 50, as well as
causing controllably arcuate segment 40 to change from a relatively
bowed geometry to a relatively straight geometry.
[0058] When the controllably arcuate segment 40 has been placed in
its relatively straight geometry, the catheter device 10 can be
removed by retracting it back over guidewire 300 and out through
the guide catheter leaving guidewire 300 and the guide catheter in
place. Alternatively, also when the controllably arcuate segment 40
has been placed in its relatively straight geometry, the handle 70
can be rotated causing catheter shaft 20 to also rotate. When
opening 50 is rotated to its desired angular position, as may be
determined using fluoroscopy and marker 51, grasper 60 can be
advanced, again causing controllably arcuate segment 40 to change
to its relatively bowed condition and simultaneously positioning
opening 50 with a minimal level of force against additional
occlusive material. Suction can again be applied, causing
additional material to be drawn through opening 50, and grasper 60
can then be retracted, causing linkage 30 and thus sliding member
100 to simultaneously retract similarly pushing the additional
material protruding through opening 50 away from opening 50 as well
as causing controllably arcuate segment 40 to change from a
relatively bowed geometry to a relatively straight geometry.
[0059] A preferred method includes the steps of 1) changing
controllably arcuate segment 40 to its relatively bowed shape; 2)
applying suction; 3) retracting grasper 60 and thus also retracting
sliding member 100; 4) advancing grasper 60 and thus also advancing
sliding member 100 simultaneously causing controllably arcuate
segment 40 to change back to a relatively straight geometry and 5)
rotating handle 70 and thus catheter shaft 20. These steps can be
repeated through a 360 degree rotation or more to remove undesired
material present along the luminal walls of a body conduit. In
addition to the above steps, longitudinal positioning, forward or
back, may also be performed, again only with the controllably
arcuate segment 40 in its relatively straight geometric condition.
It should be noted that it might not be necessary to change the
controllably arcuate segment 40 from a bowed condition to a
maximally straight geometry for some forms of repositioning such as
rotation or transluminal advancement or retraction. Partial
straightening may suffice. Also, the above description include two
distinct shapes for controllably arcuate segment 40, it should be
noted that modifications to the controlling means, such as grasper
60, linkage 30 and sliding member 100 described hereabove, can be
made to allow the operator to place controllably arcuate segment 40
in multiple transitional shapes from a maximally bowed geometry to
a maximally straight geometry.
[0060] Although this system was described specifically for a
saphenous vein graft, it is readily applicable to any stenosis of a
vessel or other applicable tubular conduit in the body. For
example, the catheter device 10 could be used to open stenoses in
the other coronary vessels, a carotid artery, dialysis fistulas,
peripheral vasculature, etc. Although the present invention has
only been described for the removal of plaque or thrombus, the
catheter device 10 could also be used to remove other stenotic or
occluding material or tissue from ducts such as the ureters or the
fallopian tubes. Mammalian patients would include both humans and
other animal patients.
[0061] FIGS. 3, 3A and 3B show another preferred embodiment of
catheter device 10 which is similar to the catheter device of FIGS.
1A and 1B with grasper 60, linkage 30 and sliding member 100 all in
a fully advanced position and controllably arcuate segment 40 in
its maximally bowed geometry. Accordingly, elements of this
embodiment which are similar to elements of catheter device 10 of
FIGS. 1A and 1B are referenced with the same reference numerals.
Referring specifically to FIG. 3, catheter device 10 includes an
aspiration chamber 72 included in handle 70. Catheter shaft 20 is
fixedly attached to handle 70 while creating a fluid path from
aspiration port 75, into aspiration chamber 72 and continuing
through aspiration lumen 21 to material collection chamber 90.
Material collection chamber 90 is in fluid communication with
opening 50 of controllably arcuate segment 40. As shown in FIG. 3,
material collection chamber 90 may be a simple continuation of
aspiration lumen 21, or material collection chamber 90 may have a
specific geometry or cavity-like structure while still in fluid
communication with aspiration lumen 21.
[0062] Present within an internal lumen of catheter shaft 20 is a
flexible shaft, linkage 30, which is preferably a hollow tube
permitting a guidewire to be inserted through its internal lumen,
linkage lumen 31. Linkage 30 may be constructed of a flexible
metal, such as a flexible steel hypotube, or a superelastic
material such as Nitinol, a nickel titanium alloy in its
superelastic state. Alternatively, linkage 30 may be constructed of
a flexible plastic tube. As shown in FIGS. 3 and 3A, an opening
around linkage 30 provides fluid communication between aspiration
chamber 72 and aspiration lumen 21. At its proximal end, linkage 30
is fixed to grasper 60 that controls the advancement and retraction
of linkage 30 and its connected components. Linkage 30 is fixed at
its distal end to sliding member 100. The grasper 60, linkage 30
and sliding member 100 are shown in the fully advanced position and
the controllably arcuate segment 40 is shown in a maximally bowed
geometry.
[0063] Referring additionally to FIG. 3A, grasper 60 surrounds and
is fixedly attached to linkage 30. The proximal end of linkage 30
includes guidewire opening 32 into which a guidewire can be placed
and from which a guidewire can exit. Linkage lumen 31 may include a
valve, not shown, in its path to prevent leakage of blood once
inserted. Alternatively, the diameter of linkage lumen 31 is chosen
to be as small as possible, slightly larger than the outside
diameter of the guidewire it is to be placed over. Linkage 30
enters handle 70 such that a relatively fluid tight seal is
created. In order to prevent fluid leakage, a sealing element,
linkage seal 71, is included that preferably consists of an
elastomeric o-ring which seals between handle 70 and linkage 30 yet
allows linkage 30 to slide back and forth as grasper 60 is advanced
and retracted. Linkage 30 may include a mechanical stop, such as
linkage stop 35, included on the outer diameter of linkage 30 to
limit the maximum retraction distance of grasper 60. Linkage stop
35 is positioned along the outer diameter of linkage 30 such that
when grasper 60 is retracted, linkage stop 35 makes contact with
the inside surface of aspiration chamber 72 and linkage seal 71
limiting further retraction. At this maximally retracted state,
shown in FIGS. 4, 4A and 4B, sliding member 100 is positioned
within controllably arcuate segment 40.
[0064] As shown in FIG. 3A, aspiration port 75 may include a valve,
connector valve 76, such that when the attachable vacuum source,
such as a vacuum generator or syringe, is not attached, fluid will
not leak out of aspiration chamber 72. Aspiration lumen 21 is in
fluid communication with aspiration chamber 72 through a clearance
around linkage 30 and an opening in the distal end of handle 70
inside of the attachment point for catheter shaft 20.
[0065] Referring additionally to FIG. 3B, Sliding member 100
includes a thru lumen continuing the guidewire clearance lumen
provided by linkage 30. At the distal end of sliding member 100 is
guidewire exit 33, which allows the guidewire to be inserted into
or exit from the device during over the wire procedures. FIGS. 3,
3A and 3B show grasper 60 in its fully advanced position, and FIG.
3b depicts the corresponding location of sliding member 100 in its
fully forward or advanced position with controllably arcuate
segment 40 shown in its maximally bowed geometry. Located at the
midpoint of controllably arcuate segment 40 is opening 50 that
creates a fluid path from the outer portion of controllably arcuate
segment 40 to material collection chamber 90. Opening 50 is sized
to allow collection of occlusive material, such as thrombus,
utilizing various applicable vacuum pressures. Opening 50 may be a
single hole or multiple holes, the holes may be round, oval or
other shape. The holes may be of uniform geometry from inside to
outside, or the holes may be tapered or transform in shape as they
pass through the wall of controllably arcuate segment 40.
Furthermore, opening 50 may be designed such that an open fluid
path is created only when controllably arcuate segment 40 is in a
relatively bowed geometry and the fluid path through opening 50 is
closed or near closed when controllably arcuate segment 40 is in a
relatively straight geometry.
[0066] In a preferred embodiment, controllably arcuate segment 40
is normally bowed and is transformed to a relatively straight
geometry when sliding member 100 is retracted to reside within the
lumen of controllably arcuate segment 40. Controllably arcuate
segment 40 can be normally bowed by a treatment, such as a heat
treatment, in the manufacturing process as has been described
hereabove, via embedded curving elements in or near the
controllably arcuate segment 40 or via other curving means. Various
designs for curving elements can be provided such as internal
curving or bending members, the details of which are described in
subsequent embodiments in detail herebelow.
[0067] FIGS. 4, 4A and 4B show the catheter device 10 of FIGS. 3,
3A and 3B with grasper 60, linkage 30 and sliding member 100 all in
a fully retracted position and controllably arcuate segment 40 in
its maximally straight geometry. Accordingly, elements of this
embodiment which are similar to elements of catheter device 10 of
FIGS. 3, 3A and 3B are referenced with the same reference numerals.
Referring specifically to FIG. 4, grasper 60 has been pulled back
from its advanced position a distance equal to retraction distance
RD. Accordingly, linkage 30 and sliding member 100 have also
traveled in a direction toward the proximal end and away from the
distal end of catheter device 10 an equivalent distance equal to
retraction distance RD. Referring additionally to FIG. 4A, the
amount of retraction distance is limited by a radial projection,
linkage stop 35, which is fixedly attached to linkage 30 and stops
further retraction when linkage stop 35 contacts linkage seal 71
and or the proximal end of aspiration chamber 72. Referring
additionally to FIG. 4B, sliding member 100, in its fully retracted
position, has its proximal portion fully contained within an
internal lumen of controllably arcuate segment 40 causing
controllably arcuate segment 40, which is naturally biased to be in
a relatively bowed geometry, to be transformed into a relatively
straight geometry. Sliding member 100 may be made from a material
more rigid than the material of catheter shaft 20, such as a metal
or a more rigid plastic or elastomer, and or its geometric
construction chosen such that controllably arcuate segment 40 is
straightened by the straight sliding member 100 in its fully
retracted position. Sliding member 100 preferably includes a thru
lumen with an exit, guidewire exit 33, that is coaxial with a
linkage lumen 31 which is a thru lumen of linkage 30.
[0068] As grasper 60 is withdrawn from its fully advanced position,
as shown in FIGS. 3, 3A and 3B, to its fully retracted position, as
shown in FIGS. 4, 4A and 4B, the proximal end, cutting end 101 of
sliding member 100 retracts toward and reaches opening 50 of
controllably arcuate segment 40. With suction applied at aspiration
port 75 and communicated to opening 50 via aspiration lumen 21 and
material collection chamber 90, loose material near the outside
surface of catheter shaft 20 in the region of opening 50 will be
pulled through opening 50 to the inside of catheter shaft 20. As
grasper 60 is continually retracted, and sliding member 100
continues to retract past opening 50, the material pulled through
opening 50 by the suction is cut and or pushed by sliding member
100 away from opening 50 further into material collection chamber
90. Simultaneous with the retraction of sliding member 100 is the
transformation of controllably arcuate segment 40 from a relatively
bowed geometry to a relatively straight geometry. FIGS. 3 and 3B
and FIGS. 4 and 4B show a controllably arcuate segment 40 with a
symmetrical geometry, specifically wherein opening 50 is at the
midpoint of the semicircle of controllably arcuate segment 40 and
the two arcs on either side of opening 50 have the same radius of
curvature and length. It should be appreciated, and considered
within the scope of this application, that various other
non-symmetrical geometries are applicable, and may be preferred,
such as a geometry wherein the controllably arcuate segment 40 has
been minimally straightened when sliding member 100 reaches opening
50 and the majority of straightening of controllably arcuate
segment 40 occurs when sliding member 100 is further retracted to
the maximum retraction of grasper 60.
[0069] Opening 50 is covered and may be sealed by sliding member
100 when grasper 60, linkage 30 and sliding member 100 are in their
fully retracted position as is limited by linkage stop 35 and
sliding member 100 has its proximal portion contained within
controllably arcuate segment 40. Continued application of vacuum or
aspiration at aspiration port 75 for the purpose of evacuating the
material severed by cutting end 101 of sliding member 100 and
contained in material collection chamber 90 may best be
accomplished with inclusion of an additional thru lumen, not shown,
to aspiration lumen 21 such that a circulatory path is provided to
properly flush out the material from collection chamber 90 through
aspiration lumen 21 and into aspiration chamber 72 where it can
then be evacuated into the vacuum source connected to aspiration
port 75. Note that in FIGS. 3, 3A, 3B, 4, 4A and 4B aspiration
lumen 21 and material collection chamber 90 are a continuous
cross-section lumen with material collection chamber 90 simply the
part of that lumen closest to opening 50 of controllably arcuate
segment 40. It should be understood, and it may be desirable, for
material collection chamber 90 to have a larger cross sectional
area than aspiration lumen 71, or to have other alternative shapes
to facilitate the collection of body material that is pushed into
material collection chamber 90 each time 1) vacuum is applied to
aspiration port 75 with opening 50 positioned at a target stenotic
location of a vessel; 2) controllably arcuate segment 40 is in a
relatively bowed geometry; and 3) sliding member 100 is
retracted.
[0070] FIGS. 5 and 5A thru 5G show another preferred embodiment of
the catheter device of the present invention which is similar to
the catheter device 10 of FIGS. 1A and 1B further comprising an
integral aspiration or vacuum assembly and a connected waste
receptacle. Accordingly, elements of this embodiment which are
similar to elements of catheter device 10 of FIGS. 1A and 1B are
referenced with the same reference numerals. Referring specifically
to FIG. 5, catheter device 10A includes a catheter shaft 20 which
is fixedly attached to handle 70 and includes one or more lumens
extending from the proximal end to a point at or near the distal
end, and may additionally include enclosed cavities or chambers
which may be used to store collected occlusive material. A chamber
within handle 70, aspiration chamber 72 includes a syringe-like
piston and plunger, plunger assembly 65. A flexible linkage,
linkage 30, exits the proximal end of handle 70 and continues
through an internal lumen of catheter shaft 20 and is connected at
its distal end to sliding member 100, shown in FIG. 5 in its fully
advanced position. Linkage 30 contains a lumen therethrough,
linkage lumen 31, which is sized to fit over a standard guidewire,
such as an 0.014 guidewire. Linkage lumen 31 includes an opening at
its proximal end, guidewire opening 32.
[0071] Controllably arcuate segment 40, shown in its maximally
bowed geometry, is again showed with a normally curved bias which
can be caused by numerous means such as those described in detail
hereabove and herebelow. Alternatively, controllably arcuate
segment 40 may have a normally straight bias, with shape control
means changing controllably arcuate segment 40 to a bowed bias as
is shown and described in detail in subsequent figures and their
detailed descriptions provided herebelow. Controllably arcuate
segment 40 has, near its midsection, an opening 50 which traverses
from the outside surface of controllably arcuate segment 40 to an
internal lumen in fluid communication with a chamber, material
collection chamber 90, used to store previously occlusive material,
such as thrombus, which has been drawn via suction through opening
50 when the controllably arcuate segment 40 is in a relatively
bowed geometry. Material collection chamber 90 is shown in fluid
communication with a lumen of catheter shaft 20, aspiration lumen
21, which is in fluid communication with aspiration chamber 72.
[0072] Alternatively, not shown, material collection chamber 90 may
be a captured cavity, in fluid communication with opening 50 only,
sized to store an appropriate amount of extracted occlusive
material. In this particular embodiment, aspiration lumen 21 would
be fluidly connected to opening 50 to permit aspiration, or an
applied vacuum, to opening 50 to draw the occlusive material
through opening 50, and may include a valve, such as a flap valve,
also not shown, to isolate aspiration lumen 21 from opening 50 and
or material collection chamber 90 when a suction is not applied via
aspiration lumen 21. Such a valve would prevent collected material
from being drawn into the aspiration lumen 21 from the material
collection chamber 90 when suction is applied to aspiration lumen
21. Similar to previous embodiments, when sliding member 100 is
withdrawn, the protruding occlusive material would be pushed into
the closed cavity material collection chamber 90.
[0073] Still referring to FIG. 5, aspiration chamber 72 has an
attached evacuation chamber, waste chamber 80, connected to
aspiration chamber 72 via waste exit 81. Referring additionally to
FIG. 5A, plunger assembly 65 includes a longitudinal shaft, plunger
shaft 61 which is fixedly connected on its proximal end to grasper
60 and includes on its distal end a flexible covering, plunger 66,
which forms a seal with the inner walls of aspiration chamber 72.
Preferably, aspiration chamber 72 has a circular cross section,
however other cross sections are viable including oval, rectangular
as well as asymmetrical cross sections. The cross section of
aspiration chamber 72 is uniform along, at a minimum, the length of
travel of plunger assembly 65 in which plunger 66 contacts the
inner walls of aspiration chamber 72. Plunger shaft 61 is made from
a rigid material such as a rigid plastic commonly used in standard
syringes, and the distal end of plunger shaft 61 has a shape
approximating the shape of the cross-section of aspiration chamber
72. Plunger 66 covers the distal end of plunger shaft 61 and is
preferably made of a flexible material such as rubber or other
material with properties to facilitate a fluid seal between the
plunger assembly 65 and the walls of aspiration chamber 72. Plunger
66 is shown as a covering for a disk-like projecting end of plunger
shaft 61 but it should be understood that various other geometries
could be utilized to form the desired seal including a simple notch
along the outer diameter of plunger shaft 61 wherein plunger 66 is
a standard O-ring.
[0074] As shown specifically in FIG. 5A, catheter shaft 20,
preferably of circular cross section, is mechanically attached to
handle 70. Aspiration lumen 21 is in fluid communication with an
internal cavity of handle 70, aspiration chamber 72 via handle
aspiration lumen 78. Handle aspiration lumen 78 may include a one
way valve, such as a duck-bill valve, aspiration valve 79 shown.
Aspiration valve 79 allows fluid and material to pass from material
collection chamber 90 and aspiration lumen 21 into aspiration
chamber 72 when negative pressure or suction is applied within
aspiration chamber 72 however prevents material from entering
aspiration lumen 21 when positive pressure is applied within
aspiration chamber 72. Negative pressure is created when plunger
assembly 65 is retracted by the operator, and positive pressure is
created when plunger assembly 65 is advanced. When positive
pressure is created, liquid and material collected in aspiration
chamber 72 exits to waste chamber 80 via waste exit 81. Waste
chamber 80 may be a rigid or preferably flexible container such as
a flexible bag or pouch. Waste exit 81 may be a piece of tubing,
attached to handle 70 to cause a fluid path to aspiration chamber
72. Waste exit 81 may include an integrated one way valve, waste
valve 82, such as a duck-bill valve similar in construction and
performance to aspiration valve 79. When plunger assembly 65 is
advanced by advancing grasper 60, the positive pressure created
drives the liquid and other material from aspiration chamber 72
into waste exit 81 and eventually waste chamber 80. Waste chamber
80 may include a vent, not shown.
[0075] Plunger shaft 61 includes a lumen therethrough, which
provides some clearance around linkage 30. Plunger shaft 61 further
includes a projection, shaft projection 62, extending radially
inward from plunger shaft 61 while making minimal or no contact
with the outer surface of linkage 30. Linkage 30 includes a
projection, linkage projection 36 extending radially outward from
linkage 30 while making minimal or no contact with the inner
surface of plunger shaft 61. The projections, linkage projection 36
and shaft projection 62 are positioned to cause a specific series
of coordinated and timed linear movements of linkage 30 and sliding
member 100 as grasper 60 and connected plunger assembly 65 are
advanced and retracted by the operator. The linear movements are
described in detail herebelow with reference to FIGS. 5A thru 5G.
As shown in FIGS. 5 and 5A, grasper 60 and plunger assembly 65 is
shown in its maximally advanced positioned, advanced position P1.
Linkage 30 and sliding member 100 are also in their maximally
advanced position as caused by shaft projection 62 forcing linkage
projection 36 forward. Plunger 66 has a surface, proximal edge 67,
which faces linkage projection 36 and when plunger assembly 65 is
in advanced position P1, proximal edge 67 is offset from linkage
projection 36. Grasper 60 is maximally advanced when it makes
contact with handle 70. Linkage 30 may include another projection,
linkage stop 35A, to limit advancement of linkage 30. Linkage stop
35A also extends radially outward and positioned along linkage 30
to limit forward travel by making contact with the distal end of
aspiration chamber 72. Each of the projections, linkage stop 35A,
linkage projection 36 and shaft projection 62 may have a ring-like
structure fully surrounding their appropriate shafts or may be one
or more rectangular projections.
[0076] Referring now to FIG. 5B and 5C, Grasper 60 has been
partially retracting causing partial retraction of plunger assembly
65 to intermediate position P2. During retraction, negative
pressure is created in aspiration chamber 72 and this suction is
communicated from aspiration chamber 72 through handle aspiration
lumen 78 and its internal valve, aspiration valve 79, into
aspiration lumen 21, through material collection chamber 90 to
opening 50. Fluid communication, in other words the effect of the
negative pressure, is cut off from waste exit 81 by the action of
waste valve 82 oriented to prevent flow from waste exit 81 into
aspiration chamber 72. Since proximal edge 67 has just made contact
with linkage projection 36, movement of plunger assembly 65 from
advanced position P1 to intermediate position P2 has not caused any
retraction of linkage 30, therefore sliding member 100 has not
moved, and controllably arcuate segment 40 remains in its bowed
geometry. When appropriately placed in a blood vessel for material
extraction, relatively loose material, such as thrombus, in the
general proximity to opening 50 would be drawn through opening 50.
It should be appreciated and understood that configurations in
which aspiration lumen 21 communicates directly with opening 50 not
by way of material collection chamber 90, configurations not shown,
could be used and is another preferred embodiment of this
application.
[0077] Referring now to FIGS. 5D and 5E, Grasper 60 has been fully
retracting causing full retraction of plunger assembly 65 to
retracted position P3. During retraction, negative pressure
continued to be created in aspiration chamber 72 and this suction
is communicated from aspiration chamber 72 through handle
aspiration lumen 78 and its internal valve, aspiration valve 79,
into aspiration lumen 21, through material collection chamber 90 to
opening 50, similar to the suction created as plunger assembly 65
retracts from advanced position P1 to intermediate position P2.
Fluid communication, in other words the effect of the negative
pressure, remains to be cut off from waste exit 81 by the action of
waste valve 82 oriented to prevent flow from waste exit 81 into
aspiration chamber 72. Movement of plunger assembly 65 from
intermediate position P2 to retracted position P3 has now caused
linkage 30 to also retract, caused by an urging force generated by
proximal edge 67 of plunger 66 pushing on linkage projection 36 of
linkage 30, simultaneously causing sliding member 100, fixedly
attached to the end of linkage 30, to also retract. The retraction
of sliding member 100 is such that the proximal longitudinal
portion of sliding member 100 resides within controllably arcuate
segment 40 and sliding member 100 is of sufficient rigidity to
cause controllably arcuate segment 40 to transition from its
normally biased curved geometry to the relatively straight geometry
of sliding member 100. The material that was previously drawn via
suction through opening 50 is pushed away from opening 50 into
material collection chamber 90 as the sliding member 100 is
retracted by plunger assembly 65 moving from intermediate position
P2 to retracted position P3.
[0078] With grasper 60 in the fully retracted position, as
represented in FIGS. 5D and 5E, plunger assembly 65 as well as
sliding member 100 are also retracted and controllably arcuate
segment 40 is in a relatively straight geometry. In this state, the
catheter device 10A could be removed from patient's body and the
procedure completed. Alternatively, additional steps of an
alternative procedure may be performed wherein additional one or
more cycles of changing controllably arcuate segment 40 from
straight to bowed geometries and back, appropriately applying
suction and retraction of sliding member 100 moving material away
from opening 50. Performance of various components and assemblies
of catheter device 10A for such additional steps are described
immediately herebelow.
[0079] Referring now to FIGS. 5F and 5G, grasper 60 has been
advanced, causing plunger assembly 65 to advance from retracted
position P3 to second intermediate position P4. Proximal edge 67 of
plunger 66 has moved away from linkage projection 36 of linkage 30
and shaft projection 62 has reached and come in contact with
linkage projection 36 such that further advancement of plunger
assembly 65 will cause linkage 30 to advance. Linkage 30 did not
yet advance as plunger assembly 65 advanced from retracted position
P3 to intermediate position P4 therefore sliding member 100 remains
in its fully retracted position wherein the proximal portion of
sliding member 100 is contained within a lumen of controllably
arcuate segment 40 such that controllably arcuate segment 40 is in
a relatively straight geometry.
[0080] Advancement of plunger assembly 65 causes positive pressure
to be generated in aspiration chamber 72 causing fluid and other
material to be evacuated from aspiration chamber 72 thru waste
valve 82 and waste exit 81 and into waste chamber 80. One way
valve, aspiration valve 79 prevents the fluid and other material
contained in aspiration chamber 72 from entering aspiration lumen
21.
[0081] Further advancement of plunger assembly 65 from second
intermediate position P4 to advanced position P1, shown in FIGS. 5
and 5A, continue the generation of positive pressure to further
evacuate the equivalent volume of fluid and material from
aspiration chamber 72 into waste chamber 80. In addition to the
positive pressure and material evacuation, linkage 30 is advanced.
Because of the initial contact between shaft projection 62 and
linkage projection 36 that occurs when plunger assembly 65 reaches
second intermediate position P4, continued advancement to advanced
position P1 causes linkage 30 to advance due to an urging force
placed upon linkage projection 36 by shaft projection 62. Referring
back to FIGS. 5 and 5A, when grasper 60 is fully advanced, its
proximal end making contact with the distal end of handle 70,
linkage 30 is fully advanced causing sliding member 100 to be fully
advanced. As sliding member is advanced, the proximal portion moves
out of controllably arcuate segment 40 allowing controllably
arcuate segment 40 to transition from a relatively straight
geometry to a relatively arcuate or bowed geometric shape.
[0082] FIG. 6 depicts another preferred embodiment of catheter
device of the present invention which is similar to the catheter
device 10 of FIGS. 1A and 1B with grasper 60, linkage 30 and
sliding member 100 all in a fully advanced position. Accordingly,
elements of this embodiment which are similar to elements of
catheter device 10 of FIGS. 1A and 1B are referenced with the same
reference numerals. Referring specifically to FIG. 6, catheter
device 10B is shown with controllably arcuate segment 40 in its
maximally straight geometry, and in this particular also preferred
embodiment, controllably arcuate segment 40 is naturally biased to
be in a maximally straight geometry as opposed to the normally
curved bias of FIGS. 1A and 1b. Catheter device 10B includes an
aspiration chamber 72 included in handle 70. Catheter shaft 20 is
fixedly attached to handle 70 while creating a fluid path from
aspiration port 75, into aspiration chamber 72 and continuing
through aspiration lumen 21 to material collection chamber 90.
Material collection chamber 90 is in fluid communication with
opening 50 of controllably arcuate segment 40 and located proximal
to opening 50. As shown in FIG. 6, material collection chamber 90
may be a simple continuation of aspiration lumen 21, or material
collection chamber 90 may have a specific geometry or cavity-like
structure while still in fluid communication with aspiration lumen
21. Material collection chamber may alternatively be fluidly
isolated from aspiration lumen 21 such as by way of an integrated
valve that allows aspiration lumen 21 to be in fluid communication
with opening 50 when vacuum or suction is applied by way of
aspiration port 75.
[0083] Present within an internal lumen of catheter shaft 20 is a
flexible shaft, linkage 30, which is preferably a hollow tube
permitting a guidewire to be inserted through its internal lumen,
linkage lumen 31. Linkage 30 may be constructed of a flexible
metal, such as a flexible steel hypotube, or a superelastic
material such as Nitinol, a nickel titanium alloy in its
superelastic state. Alternatively, linkage 30 may be constructed of
a flexible plastic tube. As shown in FIG. 6, an opening around
linkage 30 provides fluid communication between aspiration chamber
72 and aspiration lumen 21. At its proximal end, linkage 30 is
fixed to grasper 60 which controls the advancement and retraction
of linkage 30 and its connected components. Linkage 30 is fixed at
its distal end to sliding member 100. The grasper 60, linkage 30
and sliding member 100 are shown in the fully advanced position and
the controllably arcuate segment 40 is shown in a maximally bowed
geometry. Sliding member 100 has a beveled, sharpened or otherwise
tapered end, tapered cutting end 102 which faces opening 50 such
that when sliding member 100 is retracted, material protruding
through opening 50 can be severed from attached material located
within opening 50 to prevent jamming of sliding member 100. In
alternative embodiments, wherein opening 50 is distal to sliding
member 100, tapered cutting end 102 would be located on the
opposite end of sliding member 100, the distal end, such that when
sliding member 100 is advanced, material protruding through opening
50 is similarly severed.
[0084] Grasper 60 surrounds and is fixedly attached to linkage 30.
The proximal end of linkage 30 includes guidewire opening 32 into
which a guidewire can be placed and from which a guidewire can exit
if inserted from the other end. Linkage lumen 31 may include a
valve, not shown, in its path to prevent leakage of blood or other
fluid once catheter device 10B is inserted into the body.
Alternatively, the diameter of linkage lumen 31 is chosen to be as
small as possible, slightly larger than the outside diameter of the
guidewire it is to be placed over. Linkage 30 enters handle 70 such
that a relatively fluid tight seal is created, such as that created
with an elastomeric o-ring which seals between handle 70 and
linkage 30 yet allows linkage 30 to slide back and forth as grasper
60 is advanced and retracted as was described in reference to FIGS.
3 and 3a. Linkage 30 may include a mechanical stop, such as linkage
stop 35, included on the outer diameter of linkage 30 to limit the
maximum retraction distance of grasper 60. Linkage stop 35 is
positioned along the outer diameter of linkage 30 such that when
grasper 60 is retracted till linkage stop 35 is in contact with the
inside surface of aspiration chamber 72, sliding member 100 is
properly positioned within controllably arcuate segment 40, the
advanced position shown in and described with FIGS. 6, 6A and 6B.
In this preferred embodiment, the distal end of sliding member 100
extends beyond the distal end of catheter device 10 throughout the
fully advanced and fully retracted travel of grasper 60 and linkage
30.
[0085] As mentioned previously, the catheter device 10B of FIG. 6
is constructed such that the normal bias of controllably arcuate
segment 40 is a straight geometry, generally along the longitudinal
axis of catheter shaft 20. It should be noted that in this and all
other embodiments of this application, controllably arcuate segment
40 while naturally biased to be bowed or straight, is relatively
flexible, i.e. flexible enough relative to its length to allow
insertion of catheter device 10B through the body, such as through
the vascular system, without disrupting or otherwise damaging the
inner walls of conduits such as blood vessels. This flexibility may
or may not be compromised when sliding member 100 is retracted to
reside within a lumen of controllably arcuate segment 40. The
catheter device 10B of FIG. 6 further includes means to change
controllably arcuate segment 40 from its naturally straight
geometry to a relatively bowed or curved geometry. Various curving
means are described in accordance with the FIGS. 6, 6A, 6B and 7
through 10 however it should be understood and considered within
the scope of this application, that numerous alternatives are
possible to cause, based on controls that can be activated from the
proximal end of catheter device 10, such as those on or near handle
70, shape transformation of controllably arcuate segment 40.
[0086] Again, referring specifically to FIG. 6 and additionally to
FIGS. 6A and 6B, contained or embedded within the walls of
controllably arcuate segment 40 is curving element 110 which can on
command convert controllably arcuate segment 40 from a relatively
straight geometry to a relatively bowed geometry. The curving
element 110 is preferably an electrically activatable component
such as a piezo element, an electromagnetic assembly or a shaped
memory component, such as a shaped memory alloy or shaped memory
polymer. When connected to an energy source applying a voltage and
or a driving current, curving element 110 changes its shape thus
causing controllably arcuate segment 40 to also change shape.
Curving element 110 is attached to controls in handle 70 by arcuate
control wires 113, preferably flexible electrical conductors, such
as wires, embedded in or on the inside diameter of shaft 20. At the
proximal end of arcuate control wires 113 is an energy source,
power source 112, which is preferably an integrated battery or
battery assembly. Completing the electrical circuit is a switch,
arcuate control switch 111, which when depressed by the user, fully
connects power source 112 to curving element 110 thus causing both
curving element 110 and controllably arcuate segment 40 to change
geometry such as changing from a relatively straight geometry to a
relatively curved geometry. It should be noted, however, that a
similar configuration of curving element 110 can be used to change
controllably arcuate segment 40 from a relatively bowed geometry to
a relatively straight geometry when power is applied to curving
element 110. FIG. 6A depicts curving element 110 without power
attached, i.e. arcuate control switch 111 not depressed, and
controllably arcuate segment 40 in a relatively straight geometry.
FIG. 6B depicts curving element 110 with power attached, i.e.
arcuate control switch 111 depressed by the operator, and
controllably arcuate segment 40 in a relatively bowed geometry. It
may be desirable to add an indicator, not shown, to indicate the
geometric shape of controllably arcuate segment 40 when the
catheter device of the present invention is inserted into the
patient, i.e. when the controllably arcuate segment 40 cannot be
directly visualized. The shape indicating means, all not shown, may
include a visual indicator, such as an indicator light located on
the handle of the device, and or an audio indicator such as an
electronic buzzer which generate feedback to the user to indicate
the geometric shape of controllably arcuate segment 40. For
example, since the catheter device of the present invention is
generally not to be advanced or retracted unless controllably
arcuate segment 40 is in a relatively straight geometric shape, an
audio indicator may be included which creates a buzzing sound
whenever the controllably arcuate segment 40 is not in a relatively
straight geometric shape.
[0087] Still referring to FIG. 6, sliding member 100 is shown in
its fully advanced position, since grasper 60 is fully advanced
causing linkage 30 to also be fully advanced. Controllably arcuate
segment 40 has a normally straight geometric bias, and is converted
to a relatively bowed geometry by activation of curving element 110
as well as being converted back to a relatively straight geometry
by deactivation of curving element 110. Unlike the catheter device
10 of FIG. 1, sliding member 100 does not have to be used to change
the shape of a pre-curved controllably arcuate segment 40. Sliding
member 100 in FIG. 6 still however provides the function of moving
material away from opening 50 when retracted, aided by a sharpened
leading edge, tapered cutting end 102. Since sliding member 100 of
catheter device 10B of FIG. 6 does not provide the function of
changing the shape of controllably arcuate segment 40, sliding
member 100 can be made of very flexible materials which do not
impact the shape of controllably arcuate segment 40 when sliding
member 100 enters and exits the lumen of controllably arcuate
segment 40. When controllably arcuate segment 40 is in its
maximally bowed geometry as caused by curving element 110, and
vacuum is applied at opening 50 thus drawing material through
opening 50, sliding member 100 can be retracted pushing material
away from opening 50 without altering the shape of controllably
arcuate segment 40.
[0088] Referring specifically to FIGS. 6A and 6B, catheter shaft 20
has a diameter, catheter diameter D, near its distal end. When
controllably arcuate segment 40 has a relatively curved geometry,
the maximum offset from the outside diameter of catheter shaft 20
is defined as axial offset AO. In cardiovascular applications,
catheter diameter D will typically between 1.5 and 4 millimeters.
Curving element 40 has a length and radius of curvature of both its
proximal and distal arc that are chosen to create a group of
products that provide a wide range of values for axial offset AO.
Typically catheter diameter D is chosen to be applicable to
navigate the tortuosity of the vasculature to reach the target
lesion to be treated, and axial offset AO is chosen to cause the
opening 50 to be in contact, with sufficient force, to the target
lesion when controllably arcuate segment 40 is in its maximally
bowed geometry. Some applications, such as interventional
neurological procedures, may require much smaller diameters and
axial offsets, while other applications may permit or require
larger diameters and offsets.
[0089] FIG. 7 depicts another preferred embodiment of catheter
device of the present invention which is similar to the catheter
device of FIG. 6 with an integral means for curving controllably
arcuate segment 40, curving means 110 embedded within the walls of
controllably arcuate segment 40. As described previously, curving
means 110 can be of various shape altering forms, such as shaped
memory components, piezo components, electromagnetic assemblies and
other electrically and non electrically activated shape changing
components known to those of skill in the art, and all considered
within the scope of this application. Curving means 110 is attached
to electrical controlling wires, arcuate control wires 113 which
connect to power and switching means contained in the proximal
handle. Controllably arcuate segment 40 also includes one or more
holes, opening 50 which are in fluid communication with a chamber,
material collection chamber 90, into which material received
through opening 50 is pushed by tapered cutting end 102 of sliding
member 100. Linkage 30 and sliding member 100 are shown in their
fully advanced position. FIG. 7 defines a cross-sectional view A-A
directed toward the distal end of catheter shaft 20.
[0090] FIG. 8 shows a preferred embodiment of the curving element
110 located near the distal end of catheter shaft 20 shown at the
cross-sectional view A-A of FIG. 7. The curving element 110 of FIG.
8 has a tubular construction, with a circular cross section
contained within the walls of catheter shaft 20 in the region of
controllably arcuate segment 40. Alternatively but not shown,
curving element 110 may be outside of the walls within the lumen of
catheter shaft 20. Curving element 110 would include a thru-hole or
opening, curving element opening 115 which is aligned with opening
50 to allow material to pass through opening 50 and curving element
opening 115 from the outside of catheter shaft 50 to an inner lumen
of catheter shaft 20 when suction is applied. Curving element 110
is controlled from the proximal end of catheter device 10, such as
has been described hereabove, and its tubular structure changes
shape to cause controllably arcuate segment 40 to change from a
relatively straight geometry to a relatively bowed geometry or
causes controllably arcuate segment 40 to change from a relatively
bowed geometry to a relatively straight geometry. Curving element
110 may be attached to electrical wires connected to a switch and
power supply as described in FIGS. 6, 6A and 6B or other activation
means controllable from the proximal end of catheter device 10.
[0091] FIG. 9 shows another preferred embodiment of the curving
element 110 located near the distal end of catheter shaft 20 shown
at the cross-sectional view A-A of FIG. 7. The curving element 110
of FIG. 8 has a filament-like construction, with a chord-like cross
section contained within the walls of catheter shaft 20 in the
region of controllably arcuate segment 40. Alternatively but not
shown, curving element 110 may be outside of the walls within the
lumen of catheter shaft 20. Curving element 110 would be placed
away from opening 50 such that material will pass through opening
50 from the outside of catheter shaft 20 to an inner lumen of
catheter shaft 20 when suction is applied. Curving element 110 is
controlled from the proximal end of catheter device 10, such as has
been described hereabove, and its filament-like structure changes
shape to cause controllably arcuate segment 40 to change from a
relatively straight geometry to a relatively bowed geometry or
cause controllably arcuate segment 40 to change from a relatively
bowed geometry to a relatively straight geometry. Curving element
110 may be attached to electrical wires connected to a switch and
power supply as described in FIGS. 6, 6A and 6B or other activation
means controllable from the proximal end of catheter device 10.
[0092] FIG. 10 shows yet another preferred embodiment of the
curving element 110 located near the distal end of catheter shaft
20 shown at the cross-sectional view A-A of FIG. 7. The curving
element of FIG. 10 consists of two curving elements, first curving
element 110A and second curving element 110B both of which have a
filament-like construction, with a chord-like cross section
contained within the walls of catheter shaft 20 in the region of
controllably arcuate segment 40. First curving element 110A and
second curving element 110B may have different lengths and or
cross-sectional geometries, and they may be controlled together or
independently. Alternatively but not shown, first curving element
110A and or second curving element 110B may be outside of the walls
within the lumen of catheter shaft 20. Both first curving element
110A and second curving element 110B would be placed away from
opening 50 such that material will pass through opening 50 from the
outside of catheter shaft 50 to an inner lumen of catheter shaft 20
when suction is applied. Both first curving element 110A and second
curving element 110B is controlled from the proximal end of
catheter device 10, such as has been described hereabove, and the
filament-like structures change shape to cause controllably arcuate
segment 40 to change from a relatively straight geometry to a
relatively bowed geometry or cause controllably arcuate segment 40
to change from a relatively bowed geometry to a relatively straight
geometry. Independent control of first curving element 110A and
second curving element 110B can be used to create multiple states
of curvature for controllably arcuate segment 40 such as to cause
different axial offsets as has been described hereabove. Both first
curving element 110A and second curving element 110B may be
attached to electrical wires connected to a switch and power supply
as described in FIGS. 6, 6A and 6B or other activation means
controllable from the proximal end of catheter device 10.
[0093] Referring collectively to all of the figures and their
descriptions included hereabove, the catheter devices of the
present invention are intended to enter the body of a mammalian
patient, such as via percutaneous or surgical means, to perform a
therapeutic or diagnostic procedure. To properly accomplish these
types of procedures, the devices would be provided in a sterile
condition, with appropriate packaging to maintain sterility up
until use. In addition, the catheter device may be part of a kit,
with numerous other components applicable to the procedure, such as
a guide catheter and guidewire, included in the sterile packaging
or in separate sterile packaging included in the same purchased
kit. The catheter device of the present invention may be inserted
into the body over a standard interventional guidewire to assist in
advancing the device to the intended location. The various figures
and included text have described configurations wherein the device
has a guidewire that enters and exits the catheter at or near the
distal and proximal ends. Devices with this configuration utilize
guidewires which are approximately twice the length of the over the
wire device to allow placement of the device with a pre-placed
guidewire and withdrawal of the device leaving the guidewire in
place. In an alternative catheter design, also considered within
the scope of this application, near the distal end of the catheter
device is included a small length of material attached to the
catheter shaft, similar to a sidecar, which consists of a single
lumen and its surrounding walls. In this configuration, a smaller
length guidewire can be inserted through the lumen of the sidecar
only, not through the entire length of the catheter device, and the
catheter device advanced and retracted over this shorter
guidewire.
[0094] The catheter of this invention may be a precursor to other
material removal or treatment procedures such as balloon
angioplasty, stenting or other procedures. Although this system was
described specifically for a saphenous vein graft, it is readily
applicable to any stenosis of a vessel or other applicable tubular
body conduit in the body. For example, the catheter device of the
present invention could be used to open stenoses in the carotid
artery, dialysis fistulas, peripheral vasculature, etc. Although
the present invention has only described the removal of plaque or
thrombus from human vessels, the catheter device of the present
invention could also be used to remove other stenotic or occluding
tissue from ducts such as the ureters or the fallopian tubes.
Mammalian patients would include both humans and other animals.
Also, although percutaneous procedures have been described,
catheter devices of the present invention, particularly those with
larger diameters or where the intended site is a body conduit that
is not a blood vessel, could be used intraoperatively by surgical
incision into an access point appropriate for the intended
site.
[0095] In order to draw material through opening 50, a negative
pressure is applied to the inner side of opening 50 which is
communicated through a lumen within catheter shaft 20. Various
means of causing this negative pressure, also referred to
synonymously throughout this application as vacuum, suction or
aspiration, can be used. Vacuum generators can be integral to
catheter device such as has been described in reference to FIGS. 5
and 5A through 5G, or external vacuum generators can be attached
including a simple syringe to more complex aspiration and material
collection devices. The various embodiments described hereabove
show a fluid communication between aspiration lumen 21 and opening
50 that is connected via material collection chamber 90. It should
be understood and considered within the scope of this application
that aspiration lumen 21 can be connected directly to opening 50
and material collection chamber 90 isolated from the negative
pressure by way of a valve or other means. This particular
configuration is another preferred embodiment and may be useful in
avoiding clogging or otherwise obstructing aspiration lumen 21 from
being able to apply the appropriate amount of suction at opening
50. Opening 50 may include one or more holes with various
cross-sectional geometries and tapers. Opening 50 may be designed
to be fluidly closed when controllably arcuate segment 40 is in a
relatively straight geometry and open as controllably arcuate
segment 40 transforms to a bowed geometry, or opening 50 may be
fluidly open at all times.
[0096] Also, it is intended for opening 50 to be brought in close
proximity to the material to be removed, and apply a finite amount
of force to the wall of the body conduit or on the material to be
removed by the portion of catheter shaft 20 immediately surrounding
the opening, each feature intended to enhance the ability of the
vacuum to draw material through opening 50. This proximity is
achieved when controllably arcuate segment 40 is changed from a
relatively straight geometry to a relatively bowed geometry. The
various embodiments described hereabove show various configurations
of relatively bowed geometries, however it should be understood and
considered within the scope of this application that any geometry
that causes an axial offset of opening 50 from the outer surface of
the majority of catheter shaft 20 would function to bring opening
50 towards the wall of the biological conduit into which it is
inserted. It also should be understood that controllably arcuate
segment 40 may be able to assume multiple geometries with multiple
axial offsets or other geometric configurations that provide
specific advantages for the various anatomies and disease states
and locations being treated. It is preferred that a portion of
catheter shaft 20 extend beyond controllably arcuate segment 40
such that a portion of non shape altering catheter shaft exists
between the distal tip of catheter shaft 20 and controllably
arcuate segment 40.
[0097] In the various procedures described hereabove, it may be
desirable to remove material such as thrombus that may be present
at the end of catheter shaft 20. To facilitate this function, a
lumen may be provided to support simple suction removal from the
end of the catheter shaft 20, or an internal mechanism or a
removable core, such as linkage 30 and sliding member 100 may be
removable to create a lumen to which suction can be applied to
remove material from the distal end of the catheter.
[0098] In another preferred embodiment of the present invention, a
catheter device includes an elongate catheter body or shaft having
a proximal end and a distal end, a controllably arcuate segment, an
aspiration chamber located near the proximal end of the catheter
shaft, a controllably arcuate segment including at least one
opening and an aspiration lumen in fluid communication with the
aspiration chamber and one or more of the openings in the
controllably arcuate segment. This particular catheter device may
include a separate lumen to allow over the wire insertion and a
lumen to allow aspiration from the distal tip of the catheter.
[0099] The various embodiments described hereabove, such as those
described in reference to FIGS. 5 and 5A through 5G, have described
a catheter device 10A wherein retraction of grasper 60 causes
linkage 30 and thus sliding member 100 to also retract to
accomplish one or more functions including moving material away
from opening 50 in a proximal direction and into material
collection chamber 90 which is proximal to opening 50. It should be
appreciated and considered within the scope of this application
wherein material collection chamber 90 is distal to opening 50, and
advancement of grasper 60 causes advancement of linkage 30 and thus
sliding member 100 such that material is moved away from opening 50
in a distal direction into material collection chamber 90. In this
particular configuration, sliding member 100 would not exit the
distal end of catheter shaft 20 but would remain within a lumen of
catheter shaft 20 in both its fully advanced and fully retracted
positions. Similar to other embodiments, material is drawn through
opening 50 via suction from the proximal end of catheter device 10,
such as via aspiration port 75 and aspiration lumen 71.
[0100] It is to be understood and appreciated that the invention
has been described herein with reference to certain presently
preferred embodiments and examples only, and no effort has been
made to exhaustively describe all possible embodiments and examples
of the invention. Indeed, as those killed in the art will
appreciate, various additions, deletions, modifications and
variations may be made to the particular embodiments and examples
described hereabove without departing from the intended spirit and
scope of the invention. In addition, wherever steps of a method
have been described, there is no intent for a required order unless
specifically described. Accordingly, it is intended that all such
additions, deletions, modifications and variations be included
within the scope of the following claims.
* * * * *