U.S. patent application number 11/672668 was filed with the patent office on 2007-08-16 for filter/emboli extractor for use in variable sized blood vessels.
This patent application is currently assigned to ENDOVASCULAR TECHNOLOGIES, INC.. Invention is credited to David Hancock, Christopher G. M. Ken, Olin J. Palmer, Larry Voss.
Application Number | 20070191866 11/672668 |
Document ID | / |
Family ID | 26837900 |
Filed Date | 2007-08-16 |
United States Patent
Application |
20070191866 |
Kind Code |
A1 |
Palmer; Olin J. ; et
al. |
August 16, 2007 |
FILTER/EMBOLI EXTRACTOR FOR USE IN VARIABLE SIZED BLOOD VESSELS
Abstract
An extraction device for the removal of clots and foreign bodies
from vasculature. The extractor device is connected to an elongate
mandrel and is located within a longitudinally extending lumen
defined by a catheter. A clot or foreign material extracted from a
vessel by moving the extraction device and catheter proximally
until the clot or foreign material does not perfuse a critical
organ.
Inventors: |
Palmer; Olin J.; (Mountain
View, CA) ; Hancock; David; (San Francisco, CA)
; Voss; Larry; (San Jose, CA) ; Ken; Christopher
G. M.; (San Mateo, CA) |
Correspondence
Address: |
FULWIDER PATTON LLP
HOWARD HUGHES CENTER
6060 CENTER DRIVE, TENTH FLOOR
LOS ANGELES
CA
90045
US
|
Assignee: |
ENDOVASCULAR TECHNOLOGIES,
INC.
3200 Lakeside Drive
Santa Clara
CA
95054
|
Family ID: |
26837900 |
Appl. No.: |
11/672668 |
Filed: |
February 8, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10212298 |
Aug 5, 2002 |
7179273 |
|
|
11672668 |
Feb 8, 2007 |
|
|
|
09599146 |
Jun 21, 2000 |
6458139 |
|
|
10212298 |
Aug 5, 2002 |
|
|
|
60140131 |
Jun 21, 1999 |
|
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Current U.S.
Class: |
606/127 |
Current CPC
Class: |
A61B 17/221 20130101;
A61B 2017/2212 20130101; A61B 2017/00526 20130101; A61B 2017/22038
20130101; A61B 17/22 20130101; A61B 2017/22034 20130101 |
Class at
Publication: |
606/127 |
International
Class: |
A61B 17/22 20060101
A61B017/22 |
Claims
1-7. (canceled)
8. A method for removing a clot of unwanted material from a body
vessel, comprising: providing an elongate wire and a delivery
catheter having a lumen through which the elongate wire extends;
positioning the distal end of the delivery catheter adjacent to the
clot of unwanted material; advancing the elongate wire through the
lumen of the delivery catheter and across the clot of unwanted
material; rotating the elongate wire; and withdrawing the elongate
wire and clot of unwanted material from the body vessel.
9. The method of claim 8, further including: moving the clot of
unwanted material into the lumen of the delivery catheter prior to
removal from the body vessel.
10. The method of claim 8, wherein the elongate wire pierces at
least a portion of the clot of unwanted material when the elongate
wire is advanced across the clot of unwanted material.
11. The method of claim 8, wherein the elongate wire includes a
radially extending structure attached thereto which is adapted to
contact the clot of unwanted material.
12. A method for removing a clot of unwanted material from a body
vessel, comprising: providing an elongate wire having radially
extending structure attached thereto and a delivery catheter having
a lumen through which the elongate wire extends; positioning the
distal portion of the delivery catheter adjacent to the clot of
unwanted material; advancing the distal portion of the delivery
catheter through the clot of unwanted material; advancing the
elongate wire through lumen of the delivery catheter to position
the radially extending structure distal of the clot of unwanted
material; withdrawing the elongate wire and clot of unwanted
material from the body vessel.
13. The method of claim 12, further including: moving the clot of
unwanted material into the lumen of the delivery catheter prior to
removal from the body vessel.
14. The method of claim 12, further including: removing the distal
portion of the delivery catheter from contact with the clot of
unwanted material.
15. The method of claim 12, further including: rotating the
elongate wire after the radially extending structure is positioned
distal to the clot of unwanted material.
16. The method of claim 12, wherein the elongate wire includes a
plurality of radially extending structures.
17. The method of claim 12, wherein the radially extending
structure originates from one side of the elongate wire.
18. The method of claim 17, wherein the radially extending
structures are affixed to the elongate wire such that rotation of
the wire entangles the radially extending structures in the clot of
unwanted material.
19. A method for removing a clot of unwanted material from a body
vessel, comprising: providing an elongate wire having radially
extending structure attached thereto and a delivery catheter having
a lumen through which the elongate wire extends; positioning the
distal portion of the delivery catheter adjacent to the clot of
unwanted material; advancing the radially extending structure into
the clot of unwanted material; and withdrawing the elongate wire
and clot of unwanted material from the body vessel.
20. The method of claim 19, further including: moving the clot of
unwanted material into the lumen of the delivery catheter prior to
removal from the body vessel.
21. The method of claim 19, further including: rotating the
elongate wire after the radially extending structure is in contact
with the clot of unwanted material.
22. The method of claim 19, wherein the elongate wire includes a
plurality of radially extending structures.
Description
CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 10/212,298, filed Aug. 5, 2002, now U.S. Pat. No. 7,179,273,
which is a divisional of U.S. application Ser. No. 09/599,146,
filed Jun. 21, 2000, now U.S. Pat. No. 6,458,139, and is based upon
provisional application Ser. No. 60/140,131 filed Jun. 21, 1999,
entitled "FILTER/EMBOLI EXTRACTOR FOR USE IN VARIABLE SIZED BLOOD
VESSELS."
BACKGROUND OF THE INVENTION
[0002] The present invention relates to medical devices that are
useful in treating thromboembolic disorders and for removal of
foreign bodies in the vascular system.
[0003] Thromboembolic disorders, such as stroke, pulmonary
embolism, peripheral thrombosis, atherosclerosis, and the like,
affect many people. These disorders are a major cause of morbidity
and mortality in the United States.
[0004] Thromboembolic events are characterized by an occlusion of a
blood vessel. The occlusion is caused by a clot which is
viscoelastic (jelly like) and is comprised of platelets, fibrinogen
and other clotting proteins.
[0005] When an artery is occluded by a clot, tissue ischemia (lack
of oxygen and nutrients) develops. The ischemia will progress to
tissue infarction (cell death) if the occlusion persists.
Infarction does not develop or is greatly limited if the flow of
blood is reestablished rapidly. Failure to reestablish blood-flow
can lead to the loss of limb, angina pectoris, myocardial
infarction, stroke or even death.
[0006] Occlusion of the venous circulation by thrombi leads to
blood stasis which can cause numerous problems. The majority of
pulmonary embolisms are caused by emboli that originate in the
peripheral venous system. Reestablishing blood flow and removal of
the thrombus is highly desirable.
[0007] There are many existing techniques employed to reestablish
blood flow in an occluded vessel. One common surgical technique, an
embolectomy, involves incising a blood vessel and introducing a
balloon-tipped device (such as the Fogarty catheter) to the
location of the occlusion. The balloon is then inflated at a point
beyond the clot and used to translate the obstructing material back
to the point of incision. The obstructing material is then removed
by the surgeon. While such surgical techniques have been useful,
exposing a patient to surgery may be traumatic and best avoided
when possible. Additionally, the use of a Fogarty catheter may be
problematic due to the possible risk of damaging the interior
lining of the vessel as the catheter is being withdrawn.
[0008] Percutaneous methods are also utilized for reestablishing
blood flow. A common percutaneous technique is referred to as
balloon angioplasty where a balloon-tipped catheter is introduced
to a blood vessel, typically through an introducing catheter. The
balloon-tipped catheter is then advanced to the point of the
occlusion and inflated in order to dilate the stenosis. Balloon
angioplasty is appropriate for treating vessel stenosis but is
generally not effective for treating acute thromboembolisms.
[0009] Another percutaneous technique is to place a microcatheter
near the clot and infuse streptokinase, urokinase or other
thrombolytic agents to dissolve the clot. Unfortunately,
thrombolysis typically takes hours to days to be successful.
Additionally, thrombolytic agents can cause hemorrhage and in many
patients the agents cannot be used at all.
[0010] Another problematic area is the removal of foreign bodies.
Foreign bodies introduced into the circulation can be fragments of
catheters, pace-maker electrodes, guide wires, and erroneously
placed embolic material such as thrombogenic coils. There exists
retrieval devices for the removal of foreign bodies, certain of
such devices form a loop that can ensnare the foreign material by
decreasing the size of the diameter of the loop around the foreign
body. The use of such removal devices can be difficult and
sometimes unsuccessful.
[0011] Various thrombectomy and foreign matter removal devices have
been disclosed in the art. However, such devices have been found to
have structures which are either highly complex or lacking in
sufficient retaining structure. Disadvantages associated with the
devices having highly complex structure include difficulty in
manufacturability as well as use in conjunction with microcatheter.
Other less complex devices tend to pull through clots due to in
part to the lack of experience in using the same or are otherwise
inadequate in capturing clots or foreign bodies.
[0012] Moreover, systems heretofore disclosed in the art are
generally limited by size compatibility and the increase in vessel
size as the emboli is drawn out in the distal vascular occlusion
location to a more proximal location near the heart. If the
embolectomy device is too large for the vessel it will not deploy
correctly to capture the clot or foreign body and if too small in
diameter, it cannot capture clots or foreign bodies across the
entire cross section of the blood vessel. Additionally, if the
embolectomy device is too small in retaining volume, as the device
is retracted, the excess material being removed can spill out and
be carried by flow back to occlude another distal vessel.
[0013] Thus, there exists a need for an extraction device that can
be easily deployed into the circulatory system for the effective
removal of clots and foreign bodies. There is also a need for a
device which could be used as a temporary arterial or venous filter
to capture and remove thromboemboli formed during endovascular
procedures.
SUMMARY OF THE INVENTION
[0014] The present invention is directed to devices that are useful
in removing clots and foreign bodies from vessels. Various
embodiments and method of use are disclosed for the effective
removal of clots or foreign bodies. It is contemplated that the
present invention may be used in all vasculature including the
neurovasculature.
[0015] In one aspect of the invention, an elongate generally linear
wire is provided for the removal of certain types of undesirable
matter found in a blood vessel. The elongate generally linear wire
is placed within the undesirable matter and rotated to thereby
catch the matter and wind it about the wire. Withdrawing the wire
within a receiving tube or directly through the vessel operates to
extract the undesirable matter from the patient's vasculature.
[0016] In another aspect of the invention, a staged filter/emboli
extractor is provided to remove clots or foreign material from a
vessel. In one embodiment, a plurality of spaced-apart radially
extending structures are configured on an elongate wire or tubular
mandrel proximal a distal end of the mandrel. The radially
extending structures are characterized by increasing in size from
the most proximal structure to the most distal structure. In a
presently preferred embodiment, each of the radially extending
structures are in the form of a plurality of loops or petals
arranged in an annular radial array about the circumference of the
mandrel. In an alternative embodiment, each of the plurality of
loops or petals originate from a common side of the mandrel and can
be concentrically arranged.
[0017] In yet a further aspect of the invention, a knitted or mesh
structure is provided for the removal of clots or foreign material
from a blood vessel. The knitted or mesh structure is configured
near the distal end portion of an elongate wire or tubular mandrel.
In one presently contemplated embodiment, the knitted or mesh
structure is affixed in a conventional manner to the distal end of
the mandrel. In another presently contemplated embodiment, the
knitted or mesh structure surrounds a distal portion of the mandrel
and may additionally embody structure enabling one end of the
knitted or meshed structure to be translated longitudinally with
respect to its other end which is held fixed. The knitted or mesh
structures disclosed are further characterized by having open or
closed ends or a basket-like configuration.
[0018] The invention also includes an elongate tubular delivery
catheter with at least one lumen for receiving an extractor device
and for retaining the distal portion thereof in a reduced profile.
The delivery catheter may be used in conjunction with an elongate
insertion catheter that is configured to be introduced into a large
vessel and advanced within a patient's vasculature.
[0019] Generally, the clot is extracted from a vessel by capturing
the same and withdrawing the clot or foreign material proximally
until it can be removed or released into a different vessel that
does not perfuse a critical organ. The structure disclosed can also
be used as a temporary arterial or venous filter to capture and
remove thromboemboli formed during endovascular procedures. By
removing the device from the body, the clot or foreign material is
also removed.
[0020] Other features and advantages of the present invention will
become apparent from the following detailed description, taken in
conjunction with the accompanying drawings, which illustrate, by
way of example, the principles of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1a is a schematic illustration depicting an occluded
vessel with a catheter shown partially in cross-section and a first
embodiment of an extraction device of the present invention;
[0022] FIG. 1b is a schematic illustration depicting the extraction
device of FIG. 1a inserted through an occlusion;
[0023] FIG. 1c is a schematic illustration depicting the extraction
device of FIG. 1b withdrawing a clot from a vessel;
[0024] FIG. 2a is a schematic illustration depicting the extraction
device of FIG. 1a encountering a clot in another area of
vasculature;
[0025] FIG. 2b is a schematic illustration depicting the extraction
device of FIG. 2a withdrawing the clot from a vessel;
[0026] FIG. 3a is a schematic illustration depicting an occluded
vessel with a catheter and a second embodiment of extraction device
of the present invention;
[0027] FIG. 3b is a schematic illustration depicting the catheter
of FIG. 3a shown in partial cross-section and being inserted
through an occlusion;
[0028] FIG. 3c is a schematic illustration depicting the extraction
device of 3a advanced longitudinally with respect to the
catheter;
[0029] FIG. 3d is a schematic illustration depicting withdrawing
the catheter and extraction device to ensnare a clot within an
occluded vessel;
[0030] FIG. 4 is a schematic illustration depicting the second
embodiment of the extraction device being deployed within an
occlusion;
[0031] FIG. 5a is a schematic illustration depicting a first step
in manufacturing the extraction device of FIG. 4;
[0032] FIG. 5b is a schematic illustration depicting a second step
of manufacturing the extraction device of FIG. 4;
[0033] FIG. 6 depicts a third embodiment of the extraction device
of the present invention;
[0034] FIG. 7 depicts a fourth embodiment of the extraction device
of the present invention;
[0035] FIG. 8 depicts a fifth embodiment of the extraction device
of the present invention;
[0036] FIG. 9 depicts a sixth embodiment of the extraction device
of the present invention;
[0037] FIG. 10 is a schematic illustration depicting a seventh
embodiment of the extraction device of the present invention;
[0038] FIG. 11 is a schematic illustration depicting an eighth
embodiment of the extraction device of the present invention;
[0039] FIG. 12 is a schematic illustration depicting a ninth
embodiment of the extraction device of the present invention;
[0040] FIG. 13 is a schematic illustration depicting a tenth
embodiment of the extraction device of the present invention;
and
[0041] FIG. 14 is a plan view of the present invention being
deployed within an insertion catheter with a side suction port.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0042] The present invention is useful for the removal of clots or
foreign material from vasculature. The present invention is
intended to be used in various sized vessels and in vessels having
varying degrees of tortuosity. Of particular significance is the
contemplated use of the preferred embodiment in the highly tortuous
neurovasculature. Moreover, the disclosed extraction devices are
characterized by having structure that is useful as filter
devices.
[0043] Referring to FIGS. 1a-c, there is shown a first embodiment
of the present invention being used to extract a clot or foreign
material 20 from a vessel 22. In the presently preferred first
embodiment, an elongate wire 24 embodies an extraction device. The
elongate wire 24 is configured longitudinally within a lumen 26
defined by an elongate tubular delivery catheter 28.
[0044] The elongate wire 24 may comprise a conventional guidewire
or other wire structure having similar properties. One material of
choice may be Nitinol. Its exterior may be scored or include other
surface irregularities (not shown) for the purpose of enhancing
engagement with certain types of clots or foreign bodies found in a
patient's vasculature. Its outer diameter is such that it can
easily slide within the lumen 26 of the catheter 28. Generally, the
elongate wire 24 has a length greater than that of the catheter 28
so that its proximal end can be grasped by an operator and so that
the elongate wire can be advanced and withdrawn independently of
the catheter 28.
[0045] The delivery catheter 28 can be any commercially available
catheter that is made out of any appropriate biologically
compatible material. Typically, the catheter will have a single
lumen 26 as constructed out of a flexible elastomeric material such
as silicone, rubber, polyvinylchloride, polyeurothanes, polyesters,
polytetrafluoroethylene and the like. The catheter has to be
flexible enough and long enough to navigate through blood vessels
to the occluded vessel where clots or other foreign bodies 20 are
located. Typically the catheter will range in length from about 20
to about 175 centimeters.
[0046] The outer diameter of the catheter can also vary. Typically,
the outer diameter will range from about 2 to about 10 F (1 F
equals 0.013 inch). The inner diameter will range from about 1 to
about 9 F.
[0047] In use, the elongate wire 24 and catheter 28 are inserted
into a patient's vasculature using conventional techniques, using
fluoroscopy or other conventional means. The elongate wire 24 and
catheter 28 are advanced within a patient's vasculature 22 to the
location proximal to the clot or foreign body 20 to be extracted.
The elongate wire 24 is then advanced independently of the delivery
catheter 28 and across the clot or foreign material 20. Next, the
elongate wire 24 is rotated to thereby catch the clot or foreign
material 20 and wind it about the elongate wire 24. Thereafter, the
elongate wire 24 with the clot or foreign material adhered thereto
is withdrawn within the delivery catheter 28 and both the elongate
wire and delivery catheter are removed from the patient's
vasculature. Alternatively, the elongate wire 24 is directly
removed from the patient's vasculature without first withdrawing it
within the delivery catheter 28.
[0048] It has been observed that the elongate wire 24 is
particularly useful in capturing fibrin clots. As shown in FIGS.
2a-b, the elongate wire 24 is useful even where there is just a
small amount of fibrin tendril 30 of a clot 31 extending from a
branch 32 into a parent lumen 34. In such a situation, the elongate
wire 24 is placed adjacent the fibrin tendril 30 and is rotated to
first catch the fibrin 30 and then wind the clot 31 about the
elongate wire 24. The clot 31 can then be removed from the
patient's vasculature by withdrawing the elongate wire 24.
[0049] A second preferred embodiment of the present invention is
shown in FIGS. 3a-d. The second embodiment is a staged
filter/emboli extractor 40 that includes a plurality of
spaced-apart radially extending structures 42 configured on a
mandrel 44. The radially extending structure 42 each embody a
plurality of loops or petals 46 arranged in an angular radial array
about the circumference of the mandrel 44. As shown in the
break-out illustration included in FIG. 3a which depicts an end
view of one radially extending structure 42, it is contemplated
that each loop or petal 46 be configured to overlay at least a
portion of the next adjacent petal in an over-under pattern such
that each loop/petal 46 supports another loop/petal 46. It is also
contemplated that each loop/petal can overlay/underlay two or more
petals in a supporting fashion.
[0050] The number of petals or loops 46 of a radially extending
structure 42 can range from 3-8 or more depending on the size of
the petal or loop. The petal or loop itself can have a circular or
generally oval configuration with its opening defining a space
having a cross-section ranging from 0.050 inches or smaller to
2.125 inches and larger across. The wire used to form the loops 46
can be made of NiTi wire having a diameter ranging from
0.002-0.0055 inches or more.
[0051] In a preferred embodiment of the staged filter/emboli
extractor 40, there are three spaced-apart radially extending
structures formed on the mandrel 44. The petals/loops are
configured to project from the mandrel 44 at a distally directed
angle and are characterized by increasing in size or
cross-sectional profile as one moves distally along the mandrel 44.
However, it is to be recognized that as few as one and as many as
eight or more radially extending structures can be configured on
the mandrel 44. Moreover, depending on the application, the petals
can project at a proximally directed angle and can either decrease
in size or cross-sectional profile or vary as one moves distally
along the mandrel 44.
[0052] The mandrel 44 has to be relatively stiff to support the
staged filter/emboli extractor 40. In the preferred embodiment, the
insertion mandrel is made out of stainless steel and is a solid
wire from about 0.005 to about 0.038 inches in diameter. Other
materials can be used such as hard plastic, Nitinol, and the like
to make the insertion mandrel. The insertion mandrel is 10-20
centimeters longer than the catheter such that the operator of the
device (typically a physician) can control the insertion mandrel 44
by gripping the proximal end which extends from the proximal end of
the delivery catheter 28 with which it is used.
[0053] With reference to FIGS. 5a-b, in order to manufacture the
staged filter/emboli extractor 40, the wire defining the
loops/petals is formed into a hoop 52 with its lead ends 54
inserted into an hypotube 56. The hoop portion 52 is placed over a
petal mandrel 58 having an outer diameter of a particular
dimension. Different sized petal mandrels are used for forming
different sized hoops. The hypotube 56 is slid towards the petal
mandrel 58 in order to form an appropriate sized hoop 52. Next, the
hoop 52 is angled to a desirable degree with respect to the petal
mandrel 58. Angles of 30.degree. degrees or less and 80.degree.
degrees or more are contemplated. Thereafter, the wire 50 is heated
for about thirty seconds with a heat gun to approximately
1100.degree. degrees Fahrenheit for the purpose of annealing the
wire 50 and setting the angle of the wire 50 with respect to the
petal mandrel 58. The hypotube 56 is removed and the lead ends 54
of the wire are cut to a desired length. A desired number of
loops/petals 46 are formed in this matter.
[0054] Next, a coil retainer 60 is slipped over a ceramic
(non-solderable) rod 62 projecting from a support 64. The remaining
lead ends 54 of the loops/petals 46 are then placed between the
ceramic rod 62 and coil retainer 60. Thereafter, the remaining lead
ends are soldered to the retainer 60. The soldered assembly is
removed from the ceramic rod 60 and is ready to be affixed to the
mandrel 44 in any conventional manner including soldering or using
adhesives.
[0055] Multiple loops/petals 46 can alternatively be simultaneously
manufactured using a similar procedure. Generally, manufacturing
the loops/petals 46 can be accomplished by looping a single wire 50
about a combination of rods that form the loops/petals as well as
an auxiliary rod from which the loops/petals originate. Thereafter,
the multiple loops can be affixed directly to a mandrel 44 or first
cut and then affixed thereto.
[0056] In operation (see FIGS. 3a-d), the staged filter/emboli
extractor 40 is placed longitudinally within a lumen 26 defined by
a catheter 28. It is to be recognized that when the staged
filter/emboli extractor 40 is placed within the catheter 28, the
individual loops/petals 46 are held in a compressed configuration.
That is, the radially projecting structures 42 define a smaller
cross-sectional profile when contained within the delivery catheter
28, the degree of reduction in profile being controlled by the
inner diameter of the delivery catheter.
[0057] The extractor 40 and catheter 28 are then inserted into a
patient's vasculature using conventional techniques. Using
fluoroscopy or other conventional means, the extractor 40 and
catheter 28 are advanced within a patient's vasculature 22 to a
location proximal to the clot or foreign body 20 to be extracted.
The delivery catheter 28 with extractor 40 contained therein is
then advanced so that the delivery catheter 28 traverses the clot
or foreign body 20 to be extracted. The staged filter/emboli
retractor 40 is then advanced independently of the delivery
catheter 28 so that the radially projecting structures 42 are
positioned distally with respect to the clot or foreign body
20.
[0058] When the extractor 40 is so positioned, the radially
projecting structures 42 are permitted to spring outwardly and
assume an uncompressed or less compressed configuration, the angle
of the loops/petals 46 with respect to the mandrel 44 being defined
during the manufacturing process.
[0059] Subsequently, the staged filter/emboli extractor 40 is
withdrawn into engagement with the clot or foreign material 20 for
the purpose of capturing the same. While withdrawing the extractor
40 rotational movement may be applied for the purpose of enhancing
the ability of the extractor 40 to capture the clot or foreign
material 20. As the extractor and delivery catheter 28 are
continued to be withdrawn proximally, the entirety of the clot or
foreign material 20 is removed from the vessel. It is contemplated
that the radially projecting structures 42 are relied upon to
extract the clot or foreign body 20 without the interaction of the
delivery catheter 28. Alternatively, it is also contemplated that
the extractor be withdrawn within the delivery catheter once it has
engaged and captured the clot or foreign material 20.
[0060] It is to be recognized that use of combined staged variable
sized elements in a single device such as the staged filter/emboli
extractor has a number of advantages. That is, when deployed in a
distal anatomy, distal to an emboli for an example, the correct
size radially extending structure 42 engages the emboli first. As
the emboli is retracted to larger vessels, if the first radially
extending structure 42 is too small in diameter or volume, any
"spilled" material can be caught by a subsequent radially extending
structure 42. Moreover, employing multiple radially extending
structures 42 on the extractor 40 inherently has the advantage of
engaging a clot or foreign material 20 a multiple of times, thereby
assuring that any undesirable matter left behind after a first pass
will be collected during subsequent passes.
[0061] With reference to FIG. 4, it is also to be recognized that
the staged filter/emboli extractor 40 can also be deployed directly
within a clot or foreign material 20 for the purpose of removing
the undesirable matter from the patient's vasculature. Thus, rather
than deploying the extractor 40 distal to the undesirable matter
and withdrawing the extractor 40 through the same, it is possible
to also release the extractor 40 directly within the clot or
foreign material 20. In practice, it may also be beneficial to
deploy the extractor 40 so that the appropriate sized radially
extending structure 42 first engages the clot or foreign matter 20.
Once the extractor 40 has engaged and captured the undesirable
matter, the extractor 40 can be withdrawn proximally to remove such
matter from the patient's vasculature.
[0062] Moreover, in certain situations it might be beneficial to
employ a mandrel 44 which further includes a lumen (not shown)
which extends substantially the length of the mandrel 44. Such a
mandrel 44 could then be threaded over an appropriate sized
guidewire in order to facilitate the advancement of the extractor
40 within a patient's vasculature.
[0063] Various other embodiments of extractors may be useful in
removing undesirable material from blood vessels. Such other
embodiments of extractors can be deployed distally with respect of
the undesirable material and withdrawn or they can be directly
deployed within such undesirable material and thereafter removed
from the blood vessel. Moreover, other such embodiments of
extractors may be used in conjunction with a delivery catheter 28
which operates to deliver the extractor to the repair site as well
as releasably hold the extractor in a compressed configuration.
[0064] As shown in FIG. 6, a third embodiment of an extractor 70
includes a plurality of spaced-apart asymmetric radially extending
structures 72 originating from one side of the mandrel 74. By
employing asymmetric radially extending structures, it maybe easier
to manufacture the same. Additionally, such asymmetric radially
extending structures may be compressed into a catheter lumen more
easily and may more effectively handle corners or tortuous
vasculature. As with the second embodiment of the present
invention, a mandrel 74 can embody a solid or tubular structure.
The asymmetric radially extending structures 72 can number from 1
to 8 or more and can each include a plurality of concentrically
arranged loops or petals 76. The concentrically arranged loops or
petals 76 of a particular asymmetric radially extending structure
72 can number from 2 to 5 or more depending on the application and
innermost loop 78 can be a first cross-sectional size with
subsequent loops concentrically arranged thereabout having ever
increasing cross-sectional profiles.
[0065] In certain circumstances, it may be desirable to have the
asymmetric radially extending structure 72 increasing in size as
one moves distally along the mandrel 74. However, in other
instances, the asymmetric radially extending structures 72 can
decrease or otherwise vary in profile as one moves distally along
the mandrel 74. Moreover, as with the second embodiment of the
present invention, the asymmetric radially extending structures 72
are contemplated to angle distally with respect to the mandrel but
can also be angled proximally. The same materials and similar
manufacturing steps can be employed to produce the extractor 70.
Furthermore, as stated, the extractor 70 can be used in conjunction
with the delivery catheter 28 according to the method set forth
above in connection with the prior embodiments of the present
invention.
[0066] Referring to FIGS. 7-13, extractors employing knitted or
mesh structures are shown. Such extractors can also be used in
conjunction with a delivery catheter according to the methods set
forth above in conjunction with the prior embodiments of the
present invention. In particular, such extractors may be used in
connection with a delivery catheter and can be rotated, and
withdrawn to capture undesirable material.
[0067] As shown in FIG. 7, a fourth embodiment of the present
invention embodies a knitted or mesh, hollow basket-like extractor
80 which includes a basket 82 attached to a mandrel 84. The mandrel
84 can be a solid or tubular structure. The basket 82 includes a
mesh or knitted portion 86 connected by conventional means such as
welding via a plurality of proximally extending arms 88 to the
distal end of the mandrel 84. The knitted or mesh portion 86 may
form a cone-like configuration with its most distal end 89 defining
the apex of the cone. It is to be recognized, however, that other
basket configurations may also be employed. The basket-like
extractor 80 is characterized by providing structure which may be
particularly useful in collecting matter in its hollow interior as
blood flows therethrough.
[0068] As shown in FIG. 8, a fifth embodiment in the present
invention includes a hollow knitted or mesh extractor 90 attached
to a distal end of a solid or tubular mandrel 92. In this
embodiment, the knitted or mesh portion has a cone-like proximal
portion 94 that is welded or otherwise affixed to the distal end of
the mandrel 92 as well as a generally cylindrical distal portion 96
which extends integrally from the proximal portion 94. The distal
most end 98 of the knitted or mesh structure terminates at a
generally right angle to a longitudinal axis of the knitted or mesh
portion and further defines an opening to the hollow interior of
the device. This device may provide a relatively larger
cross-section for blood to flow through its distal end while the
device continues to trap undesirable material in a blood vessel or
compress the same against the vessel wall.
[0069] A sixth embodiment of the present invention is shown in FIG.
9. In this presently preferred embodiment, a knitted or mesh
structure 100 is attached by conventional means such as welding to
a distal end of a solid or tubular mandrel 102. The knitted or mesh
structure 100 has a hollow interior and further includes a
proximally directed cone-like portion 104 attached to the mandrel
102, a generally cylindrical mid-section 106 extending integrally
from the proximal portion 104, and a distally directed cone-like
portion 108 extending integrally from the generally cylindrical
mid-section 106. Such a device may provide the advantage of
improved deployability in that it might be more easily ejected from
a delivery catheter and permitted to more fully expand.
[0070] A seventh embodiment of the present invention is shown in
FIG. 10. In this contemplated embodiment, a knitted or mesh
cup-like structure 110 is affixed to a solid or tubular mandrel 112
proximal to a distal end of the mandrel 112. The cup-like structure
110 includes a proximally directed, generally circular opening 114
which provides access to an interior of the hollow device. The
cup-like structure 110 also includes a distal end portion 116 that
narrows in a cone-like fashion, the distal most part 118 of which
is attached to the mandrel 112. In certain circumstances, it may be
desirable to employ a collar (not shown) to aid in so affixing the
device to the mandrel 112.
[0071] As shown in FIG. 11, an eighth embodiment of the present
invention embodies a basket-like extractor 120 which includes a
plurality of arms 122, one end of each of which being affixed to a
solid or tubular mandrel 124, the other end of each of which being
attached to or looped about a hollow basket 126. The basket 126
includes a proximal generally cylindrical portion 127 and a distal
portion 128 integrally extended therefrom in a cone-like matter.
The very distal end portion of the distal portion 128 surrounds the
mandrel 124 such that it can slide independently over the mandrel
124.
[0072] A ninth embodiment in the present invention is depicted in
FIG. 12. In this embodiment, the extractor includes a hollow
knitted or mesh structure 132 that has a generally cylindrical
mid-section 133, and proximal 134 and distal 135 portions
integrally extending from the mid-section 133 and which narrow in a
cone-like manner therefrom. The proximal portion 134 is welded or
otherwise affixed to a solid or tubular mandrel 136. The distal
portion 135 surrounds the mandrel 136 in a manner such that the
distal portion can slide independently of the mandrel 136. A collar
138 can be employed to aid in affixing the proximal end 134 to the
mandrel 136.
[0073] As shown in FIG. 13, a tenth embodiment of the present
invention includes a braided or knitted balloon 140. A distal end
142 of the balloon 140 is attached to a distal end of a central
mandrel 144, whereas its proximal end is attached to a distal end
145 of an elongate outer tube assembly 146. In the presently
preferred embodiment, the mandrel 144 is configured longitudinally
within the outer tube assembly 146. It is also contemplated that
the mandrel 144 have a length greater than the outer tube 146 so
that an operator can grasp both the mandrel 144 and outer tube
assembly 146 independently. Through manipulation of the outer tube
assembly 146 independently of the mandrel 144, the braided balloon
140 can be caused to expand or contract radially.
[0074] In order to manufacture the knitted or braided structure of
the aforementioned extractors, either a plurality of wires or a
single wire can be used. It is contemplated that the wires be
comprised of Nitinol or other materials having similar properties.
In the event a plurality of wires are used to form the knitted or
mesh structures, four spaced-apart wires for example, may be
wrapped in helical fashion in a clockwise direction about a mandrel
(not shown) having a desired profile. The forming mandrel itself is
used to define the profile of the resulting extractor
configuration. An additional like number of spaced wires could
simultaneously be helically wrapped in a counter clockwise
direction in an over/under pattern with the wires being wrapped
about the mandrel in a clockwise direction to thereby form the
desired knitted or mesh configuration. Alternatively, a single wire
can be wrapped in a helical fashion about a mandrel (not shown)
that includes a plurality of pegs extending from the ends of the
mandrel, the pegs being employed to aid in reversing the direction
of winding. An over/under pattern of winding may also be employed
to produce the desired knitted or mesh structures. A particular
advantage of using one wire to form the knitted or mesh structure
is that such a resultant structure is characterized by having
atraumatic ends, a high expansion ratio and high flexibility.
[0075] The size of the filament or wire employed to construct the
braid as well as angles between the filaments can be selected for
the particular application. Moreover, the radial and longitudinal
dimensions of the braid structure can likewise be varied for a
particular application. However, the same effective range of
dimensions contemplated for the second and third embodiments
described above would be acceptable for the knitted or braided
embodiments.
[0076] The extractors/filters and delivery catheter systems
heretofore described are also contemplated to be used with an
insertion catheter. A particularly useful insertion catheter is
illustrated in FIG. 14 (the extractor being schematically
represented at a distal end of the assembly). The insertion
catheter 150 is hollow with a single lumen and has a Y junction
towards its proximal end. The insertion catheter is a standard
commercially available catheter. The insertion catheter has two
ports, 152 and 154. Port 152 is in straight communication with the
longitudinal axis of the insertion catheter 150 and is useful for
the insertion of the delivery catheter 28 and an extractor of the
present invention and mandrels associated therewith. The other
port, which is angled away from the longitudinal axis of the
insertion catheter, is for the attachment to a suction line from a
vacuum source. Located at the distal end 156 of the insertion
catheter is a marker band 158 that can be located via radiographic
means while the insertion catheter is being used.
[0077] In practice, the insertion catheter 150 is inserted through
a large vessel and through the vascular system to a position near a
clot or foreign body in an occluded artery under fluoroscopic
guidance. The delivery catheter 28 is then inserted through port
152 and through the insertion catheter 150 such that the distal end
of the catheter 28 has passed the distal end 156 of the insertion
catheter 150. The delivery catheter 28 or extractor is then
translated across the clot or foreign body (not shown). The mandrel
is then translated proximally to ensnare the foreign body or clot
which is then translated toward the distal end 156 of the insertion
catheter 150. Once the clot or foreign body is at the distal end
156, suction is applied via port 154 to suck part of the same into
the distal end 156. Thereafter, the insertion catheter 150, the
delivery catheter 28, the extractor and undesirable material are
removed from the patient.
[0078] It is also contemplated that the present invention can be
used as a filter in a blood vessel. In such a situation, the
above-described extractors are deployed within a blood vessel and
held stationary for a period of time sufficient for the extractor
to remove unwanted material from a patient's bloodstream.
[0079] Thus, an extractor system is disclosed which allows for the
removal of thromboembolic material and foreign bodies from a blood
vessel. While several particular forms and applications of the
invention have been illustrated and described, it will be apparent
to those skilled in the art that many more modifications are
possible without departing from the spirit and scope of the
invention. The invention, therefore, is not to be restricted except
in the spirit of claims appended hereto.
* * * * *