U.S. patent application number 10/278172 was filed with the patent office on 2003-08-14 for emboli filtration system and methods of use.
Invention is credited to Bates, Mark C., Hogendijk, Michael.
Application Number | 20030150821 10/278172 |
Document ID | / |
Family ID | 34637094 |
Filed Date | 2003-08-14 |
United States Patent
Application |
20030150821 |
Kind Code |
A1 |
Bates, Mark C. ; et
al. |
August 14, 2003 |
Emboli filtration system and methods of use
Abstract
An emboli filtration apparatus is provided comprising a guide
wire having a filter element captured thereon, so that the guide
wire is free to rotate and translate while the filter element
remains stationary. The apparatus allows for movement and rotation
of the guide wire as devices are advanced over it to treat
occlusive disease, substantially without dislodging the filter
element. In a preferred embodiment, the guide wire comprises a
proximal stop configured to reposition the filter element during a
medical procedure without having to remove or insert additional
interventional devices.
Inventors: |
Bates, Mark C.; (Charleston,
WV) ; Hogendijk, Michael; (Palo Alto, CA) |
Correspondence
Address: |
FISH & NEAVE
1251 AVENUE OF THE AMERICAS
50TH FLOOR
NEW YORK
NY
10020-1105
US
|
Family ID: |
34637094 |
Appl. No.: |
10/278172 |
Filed: |
October 21, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10278172 |
Oct 21, 2002 |
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09774197 |
Jan 29, 2001 |
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6468291 |
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09774197 |
Jan 29, 2001 |
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09354897 |
Jul 16, 1999 |
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6179859 |
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Current U.S.
Class: |
210/767 ;
210/359; 210/780; 606/200 |
Current CPC
Class: |
A61F 2/0108 20200501;
A61F 2002/015 20130101; A61M 2025/09183 20130101; A61F 2/013
20130101; A61F 2230/0006 20130101; A61M 25/104 20130101; A61F 2/011
20200501; A61F 2002/018 20130101; A61F 2230/0067 20130101 |
Class at
Publication: |
210/767 ;
210/359; 606/200; 210/780 |
International
Class: |
B01D 035/00; B01D
037/00 |
Claims
1. Apparatus for filtering emboli from blood flowing through a
vessel, the apparatus comprising: a guide wire having proximal and
distal regions, and proximal and distal stops on the distal region;
and a filter element configured to rotate and translate on the
guide wire between the proximal and distal stops, wherein the
filter element and the proximal stop are configured to permit
advancement of the filter element from the proximal region by
passing in vivo over the proximal stop, the proximal stop
thereafter prohibiting proximal retraction of the filter element
over the proximal stop.
2. The apparatus of claim 1 wherein the distal stop limits
translation of the filter element in a distal direction.
3. The apparatus of claim 1 wherein the proximal stop has proximal
and distal ends and a taper disposed therebetween.
4. The apparatus of claim 3 wherein the proximal end has a first
diameter that is less than a second diameter of the distal end.
5. The apparatus of claim 3 wherein the filter element comprises a
compliant member configured to pass over the proximal stop.
6. The apparatus of claim 1 wherein the proximal stop and distal
stop are spaced apart such a distance that the filter element, when
deployed therebetween, will not be disturbed by incidental
longitudinal movements of the guide wire.
7. The apparatus of claim 1 wherein the proximal stop is configured
to abut against a proximal portion of the filter element, after the
filter element is moved to the distal region, when the guide wire
is advanced.
8. The apparatus of claim 1 further comprising a plurality of
self-expanding struts coupled between a capture ring and a filter
sac.
9. The apparatus of claim 1 wherein the proximal stop comprises at
least one depressible tab having proximal and distal ends, wherein
the proximal end is affixed to the guide wire.
10. The apparatus of claim 9 wherein the distal end of the
depressible tab is biased radially outward from the guide wire in a
relaxed state.
11. The apparatus of claim 10 wherein the distal end of the
depressible tab is configured to abut against the filter element
once the filter element is moved to the distal region.
12. The apparatus of claim 10 wherein the depressible tab further
comprises a contracted state in which the distal end is
substantially flush with an exterior surface of the guide wire.
13. The apparatus of claim 9 wherein the depressible tab is
configured to facilitate distal advancement of the filter element
over the proximal stop in the contracted state.
14. The apparatus of claim 1 wherein the proximal stop includes a
bent section of the guide wire, the bent section including a
proximal taper and a distal taper.
15. The apparatus of claim 14 wherein the proximal taper comprises
a first angle with respect to a longitudinal axis of the guide wire
and the distal taper comprises a second angle with respect to the
longitudinal axis, wherein the first angle is less than the second
angle.
16. A method for filtering emboli from blood flowing through a
vessel, the method comprising: providing apparatus comprising a
guide wire having a distal region including a distal stop, a
proximal stop disposed proximal of the distal stop, and a filter
element disposed for-translation on the guide wire; transluminally
inserting the guide wire into a vessel; distally advancing the
filter element in a contracted state over the proximal stop; and
deploying the filter element, distal of the proximal stop and
proximal of the distal stop, to engage a wall of the vessel and
filter emboli out of blood flowing through the vessel.
17. The method of claim 16 further comprising advancing a treatment
device along the guide wire to treat a portion of the vessel
proximal of the location of the filter element, wherein incidental
rotation or translation of the guide wire relative to the filter
element does not displace the filter element.
18. The method of claim 17 further comprising a step of, after use
of the treatment device is completed, pulling the guide wire
proximally so that the distal stop engages the filter element and
causes the filter element to return to the contracted state.
19. The method of claim 16 further comprising: distally advancing
the guide wire; and causing the proximal stop to abut and urge the
filter element distally.
20. The method of claim 16 wherein providing apparatus comprising a
proximal stop comprises providing a taper on the guide wire, the
method further comprising: distally advancing the filter element in
the contracted state over the taper; and causing a distal end of
the taper to abut and reposition the filter element when the guide
wire is advanced distally by a physician.
21. The method of claim 16 wherein providing apparatus comprising a
proximal stop comprises providing a bent section of the guide wire
having proximal and distal tapers, the method further comprising:
distally advancing the filter element in the contracted state over
the proximal and distal tapers; and causing the distal taper to
abut and reposition the filter element when the guide wire is
advanced distally by a physician.
22. The method of claim 16 wherein providing apparatus comprising a
proximal stop comprises providing at least one depressible tab
having a proximal end affixed to the guide wire and a distal end,
the method further comprising: providing the depressible tab in a
relaxed state wherein the distal end is biased radially outward
from an exterior surface of the guide wire; distally advancing the
filter element over the depressible tab to cause the distal end of
the depressible tab to be substantially flush with the exterior
surface of the guide wire; and returning the depressible tab to the
relaxed state after the filter element is advanced distal of the
proximal stop.
Description
REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a continuation-in-part of U.S.
patent application Ser. No. 09/774,197, filed Jan. 29, 2001, which
is a continuation-in-part of U.S. patent application Ser. No.
09/354,897, filed Jul. 16, 1999, now U.S. Pat. No. 6,179,859.
FIELD OF THE INVENTION
[0002] The present invention relates to apparatus and methods for
removing emboli from the blood stream that are generated during
treatment of vascular disease, such as angioplasty, atherectomy or
stenting. More particularly, an emboli filtration device and
methods are provided having a captured filter that enables movement
of a guide wire associated with the filter without displacing the
filter.
BACKGROUND OF THE INVENTION
[0003] Atherosclerosis and other vascular occlusive diseases are
becoming prevalent today in many developed countries. In such
diseases, the flow areas of blood vessels become narrowed or
occluded by the buildup of plaque on the walls of the vessels,
leading to ischemia, and depending upon the location of the vessel,
damage to the organ or limb. A number of surgical and percutaneous
procedures have been developed for treating stenosis in the
coronary arteries and carotid arteries, including endarterectomy,
angioplasty, atherectomy and stenting.
[0004] One problem frequently encountered during such procedures is
that pieces of plaque ("emboli") often are dislodged from the
stenosis or the vessel wall. Such emboli may travel into smaller
diameter regions of the vasculature, blocking blood vessels and
causing ischemic injury. This problem is especially severe where
the emboli are permitted to travel into the coronary arteries and
carotid arteries, and can result in infarction, stroke and even
death.
[0005] Emboli filtration devices are known in which filter elements
are deployed against the walls of a vessel distal of a stenosis.
Such filters typically comprise a polymer or wire sac mounted on a
distal region of a guide wire or angioplasty catheter, and permit
blood to flow through the filter while trapping emboli. Once
treatment of the stenosis is completed, the filter containing the
captured emboli is contracted and withdrawn from the vessel.
[0006] For example, U.S. Pat. No. 5,814,064 to Daniel et al.
(Daniel) describes an emboli capturing system having a radially
expandable mesh filter disposed on the distal end of a guide wire.
The filter is deployed distal of a region of stenosis, and any
interventional devices, such as an angioplasty balloon or stent
delivery system are advanced along the guide wire. The filter is
designed to capture emboli generated during treatment of the
stenosis while permitting blood to flow through the filter.
[0007] U.S. Pat. No. 4,723,549 to Wholey et al. (Wholey) describes
an angioplasty catheter having a filter element disposed on its
distal end. The filter is supported on a plurality of
circumferential struts, and is expanded against an interior wall of
a vessel, distal of a stenosis, by an inflation balloon. An
angioplasty balloon is disposed on the catheter proximal of the
filter for dilating the stenosis. The filter captures emboli
dislodged during the dilatation procedure, and then is contracted
and removed from the vessel with the angioplasty catheter.
[0008] A key disadvantage of previously known emboli filtration
systems, such as described in the foregoing patents, is that the
filters in those devices are fixedly attached to the guide wire or
angioplasty catheter, respectively. If the catheter or guide wire
is rotated, bumped or moved after the filter has been deployed,
there is a substantial risk that the filter will become temporarily
dislodged or skewed, thereby permitting emboli to escape past the
filter. Such motion is especially likely to occur when other
devices such as an angioplasty balloon catheter are deployed along
the guide wire after the filter is deployed, as in the Daniel
patent.
[0009] U.S. Pat. No. 6,336,934 to Gilson et al. (Gilson) describes
an embolic protection device having a collapsible filter element
that is mounted on a tubular sleeve, wherein the tubular sleeve is
slidable and rotatable on a guide wire between proximal and distal
stops. The filter element on the tubular sleeve is delivered in a
collapsed state within a catheter and self-deploys when the
catheter is retracted. In the deployed state, the tubular sleeve
facilitates some manipulation of the guide wire while potentially
reducing disruption of the filter element.
[0010] One drawback associated with the device described in the
Gilson patent is that the guide wire is delivered into the
patient's vessel with the filter element disposed in a collapsed
state between the proximal and distal stops near the distal end of
the guide wire. The placement of the filter element near the distal
end of the guide wire during delivery may make it difficult for the
guide wire to negotiate tortuous anatomy during delivery. It would
be advantageous to deliver the guide wire in an unencumbered manner
to the site of the occlusion, then subsequently deliver other
interventional devices including the filter element.
[0011] In view of these drawbacks of previously known devices, it
would be desirable to provide emboli filtration apparatus and
methods having a filter element that remains stationary once
deployed.
[0012] It also would be desirable to provide emboli filtration
apparatus and methods having a filter that may be deployed along a
guide wire, but is configured so that subsequent displacements or
rotation of the guide wire will not dislodge the filter.
[0013] It further would be desirable to provide emboli filtration
apparatus and methods that reduce the risk of emboli escaping from
a filter element.
[0014] It still further would be desirable to provide emboli
filtration apparatus and methods that reduce the risk of trauma to
vessel endothelium resulting from movement transferred to the
emboli filtration apparatus.
[0015] It still further would be desirable to provide emboli
filtration apparatus and methods that enable a filter element to be
repositioned during a medical procedure without having to remove or
insert additional interventional devices.
SUMMARY OF THE INVENTION
[0016] In view of the foregoing, it is an object of the present
invention to provide emboli filtration apparatus and methods having
a filter element that remains stationary once deployed.
[0017] It is another object of the present invention to provide
emboli filtration apparatus and methods having a filter that may be
deployed along a guide wire, but is configured so that subsequent
displacements or rotation of the guide wire will not dislodge the
filter.
[0018] It is also an object of this invention to provide emboli
filtration apparatus and methods that reduce the risk of emboli
escaping from a filter element.
[0019] It is a further object of the present invention to provide
emboli filtration apparatus and methods that reduce the risk of
trauma to vessel endothelium resulting from movement transferred to
the emboli filtration apparatus.
[0020] It is still a further object of the present invention to
provide emboli filtration apparatus and methods that enable a
filter element to be repositioned during a medical procedure
without having to remove or insert additional interventional
devices.
[0021] These and other objects of the present invention are
accomplished by providing emboli filtration apparatus comprising a
guide wire having a filter element captured thereon, so that the
guide wire is free to rotate and translate while the filter element
remains stationary. The apparatus thus allows for movement and
rotation of the guide wire as devices are advanced over it to treat
a stenosis, substantially without dislodging the filter element.
Accordingly, the risk of permitting emboli to escape during
temporary displacement or skewing of the filter element is reduced,
as well as movement-induced trauma of the vessel endothelium.
[0022] In a preferred embodiment, the apparatus comprises a guide
wire having a filter element captured for rotation and translation
on a distal end thereof. The filter element preferably comprises a
wire or polymer sac affixed to a plurality of self-expanding
struts. The filter element has a contracted state, suitable for
transluminal insertion disposed inside a retractable sheath, and a
deployed state, wherein an outer perimeter of the filter element
engages the walls of a vessel when the sheath is retracted
proximally.
[0023] The filter element includes a proximal capture ring having a
diameter that is larger than the diameter of the guide wire, but
smaller than the diameter of the distal tip of the guide wire. The
capture ring allows the guide wire to move freely relative to the
filter element over a limited range, so that movement or rotation
of the guide wire does not cause the filter to move or to scrape
against the walls of the vessel. When it is desired to retract the
filter element, the guide wire is pulled proximally so that the
distal tip of the guide wire engages the capture ring and pulls the
filter element back into a sheath to its contracted state.
[0024] Optionally, the filter element may include a cylindrical
sleeve that ensures that the filter forms an adequate seal against
the walls of the vessel in the deployed state, thus preventing
bypass flow around the filter. The sleeve also assists in orienting
the axis of the filter element parallel to the axis of the
vessel.
[0025] In a further alternative embodiment of the present
invention, the guide wire further comprises a proximal stop
disposed proximal of the distal tip. The proximal stop is
configured so that a filter element having an elastomeric capture
ring may be advanced distally over the proximal stop during
delivery of the filter element and locked distal of the proximal
stop. As a further alternative, the proximal stop may be configured
to permit the capture ring to pass distally over it, but prevent
proximal passage.
[0026] During a medical procedure, the filter element is advanced
to a central position between the proximal stop and distal tip.
Advantageously, if it becomes necessary to advance the filter
element distally during the medical procedure, the guide wire may
be advanced distally to cause the proximal stop to abut the capture
ring and urge the filter element distally. Using the proximal stop
of the guide wire, it is not necessary to remove interventional
devices or insert a push tube over the guide wire to reposition the
filter element.
[0027] Methods of using the apparatus of the present invention to
remove emboli during a surgical or percutaneous transluminal
procedure also are provided.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] Further features of the invention, its nature and various
advantages will be apparent from the accompanying drawings and the
following detailed description of the preferred embodiments, in
which:
[0029] FIG. 1 is a side view of the components of a first
embodiment of apparatus constructed in accordance with the
principles of the present invention;
[0030] FIGS. 2A-2B are, respectively, a perspective view and end
view of the filter element of FIG. 1;
[0031] FIGS. 3A-3E are side sectional views showing deployment, use
and removal of the apparatus of FIG. 1 in accordance with the
methods of the present invention;
[0032] FIGS. 4A-4B are, respectively, side sectional views of an
alternative embodiment of the apparatus of the present invention in
deployed and contracted states;
[0033] FIGS. 5A-5B are side sectional views depicting use of an
alternative embodiment of the present invention having a proximal
stop disposed on a guide wire;
[0034] FIGS. 6A-6C are, respectively, a side view of an alternative
embodiment of the proximal stop of FIGS. 5A-5B, and enlarged views
of the proximal stop in relaxed and contracted states; and
[0035] FIGS. 7A-7B are side views of a further alternative
embodiment of a proximal stop provided in accordance with
principles of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0036] The present invention is directed to an emboli filtration
system and methods that filter out emboli generated during surgical
or percutaneous interventional procedures. In accordance with the
principles of the present invention, a filter element is captured
on a guide wire so that the guide wire is capable of rotation and
translation, without disturbing the placement of the filter
element. Because the filter element is captured on the guide wire,
however, the filter element is readily removed by retracting the
guide wire into a sheath.
[0037] Referring to FIG. 1, apparatus 10 of a first embodiment of
the present invention comprises guide wire 11, delivery sheath 20
and filter element 30. In accordance with the principles of the
present invention, guide wire 11 includes enlarged diameter distal
region 12. Guide wire 11 may be constructed of material commonly
used in guide wire construction, such as stainless steel or a high
strength polymer. Distal region 12, which acts as a distal stop to
limit travel of filter element 30 in the distal direction,
comprises a soft metal or metal alloy coil or may be formed from a
flexible polymer, such as polyethylene or nylon, molded onto the
distal region of the guide wire. Alternatively, guide wire 11 and
distal region 12 may comprise a mechanism, such as are known in the
art, for steering distal region 12 through a patient's vasculature.
Illustratively, guide wire 11 may have a diameter of about 0.018
inches (0.46 mm) and the diameter of distal region 12 may be about
0.022 inches (0.56 mm).
[0038] Delivery sheath 20 comprises flexible catheter 21 having
proximal end 22, distal end 23, and interior lumen 24. Push tube 25
is disposed within lumen 24, and includes proximal end 26, distal
end 27 and guide wire lumen 28, to permit catheter 21 and push tube
25 to be advanced along guide wire 11. Proximal end 26 of push tube
25 extends through proximal end 22 of catheter 21, so that push
tube 25 may be translated in the distal and proximal directions
relative to catheter 21. Catheter 21 and push tube 25 preferably
comprise flexible materials such as are commonly used in catheter
construction, for example, polyethylene, polyurethane or nylon.
Delivery sheath 20 preferably has an outer diameter of about 4
Fr.
[0039] Referring now to FIGS. 2A and 2B, filter element 30
comprises funnel-shaped filter sac 31 coupled to plurality of
self-expanding struts 32 at proximal end 33 and soft elastomeric
cone 34 at distal end 35. Struts 32 are affixed to capture ring 36,
and self-expand from a contracted state, when filter element is
disposed in lumen 24 of catheter 21, and a deployed state, when
filter element is ejected from delivery sheath 20. In the deployed
state, struts 32 extend outward to urge the perimeter of sac 31
into engagement with the walls of a vessel.
[0040] Struts 32 may comprise a resilient metal or metal alloy,
such as stainless steel or nickel-titanium, or a resilient polymer.
It is expected that at least three struts 32 spaced equidistant
apart around the perimeter of sac 31 should be employed to provide
adequate expansion and control of the sac, although a greater
number may be used. Alternatively, struts 31 may comprise flexible
strands, and expansion of sac 31 may be accomplished by adding a
flexible and resilient self-expanding nickel-titanium hoop along
perimeter 38 of the sac.
[0041] Particulate matter, such as emboli, pass through struts 32
and are trapped against sac 31, which permits blood to pass freely
through. The size of emboli trapped by sac 31 is determined by the
pore size of the sac, and preferably is about 0.0012 inches (30
microns). Sac 31 may comprise a polymer sleeve affixed to struts 32
or a self-expanding wire mesh constructed from a resilient metal
alloy, for example, nickel-titanium.
[0042] Capture ring 36 has bore 37 with an inner diameter greater
than the diameter of guide wire 11, but smaller than the diameter
of distal region 12. This allows guide wire 11 to be rotated or
translated distally relative to filter element 30, without imposing
a force on the filter element that might temporarily dislodge the
filter element. Accordingly, various devices, such as angioplasty
catheters, atherectomy devices or stent delivery systems may be
exchanged on guide wire 11 without disturbing filter element 30 or
causing it to scrape against the walls of the vessel. As will of
course be understood, capture ring 36 need not be a tubular member,
but may have any suitable shape that allows guide wire 11 to pass
freely through it.
[0043] Elastomeric cone 34 is coupled to the distal end of sac 31
and includes a tapered central lumen that permits guide wire 11 to
freely pass through cone 34 with minimal clearance. Elastomeric
cone 34 preferably comprises a non-stick or slick surface, such as
polytetrafluoroethylene, and is designed so that emboli trapped in
sac 31 are prevented from passing out of the filter element through
the space between guide wire 11 and the lumen of elastomeric cone
34. Cone 34 is sufficiently soft and flexible so that its lumen can
expand to permit distal region 12 of guide wire 11 to be pulled
proximally through the cone, and then the lumen will seal itself to
prevent emboli from escaping through the lumen, as described
hereinafter.
[0044] Referring now to FIGS. 3, preferred methods of using the
apparatus of FIG. 1 are described. In FIG. 3A, guide wire 11 first
is percutaneously and transluminally inserted into vessel V, such
as a coronary artery or common carotid artery, so that distal
region 12 is disposed distal of stenosis S in the direction of
blood flow (indicated by arrow F).
[0045] In FIG. 3B, delivery sheath 20 with filter element 30 loaded
in lumen 24 in the contracted state is advanced along guide wire 11
until the filter element is disposed at a desired location distal
of the stenosis, as determined, for example, by fluoroscopy.
Proximal end 26 of push tube 25 is then held stationary while
catheter 21 is retracted in the proximal direction.
[0046] As catheter 21 is retracted, struts 32 of filter element 30
expand outward to urge the perimeter of sac 31 into engagement with
the walls of vessel V, as depicted in FIG. 3C. Delivery sheath 20
then is withdrawn proximally and removed from guide wire 11. Guide
wire 11 then may be advanced a short distal distally, so that any
incidental movement of the guide wire associated with exchanging
interventional instruments along guide wire 11 will not cause
distal region 12 to contact filter element 30.
[0047] In FIG. 3D, angioplasty catheter 40 is illustratively
advanced along guide wire 11 until balloon 41 is disposed across
the stenosis. Balloon 41 then is inflated and deflated for one or
several cycles, as in conventional, to dilate and disrupt the
plaque comprising stenosis S and increase the diameter of vessel V.
During this dilatation procedure, particles of plaque or emboli E
are generated. These emboli are carried by blood flow in direction
F into sac 31 of filter element 30, where they become trapped.
[0048] Insertion and advancement of angioplasty catheter 40 along
guide wire 11 may cause the guide wire to be translated over a
short range or rotated. Because filter element 30 is not affixed to
guide wire 11, however, such motion of the guide wire is not
transferred to the filter element. Instead, filter element 30
remains stationary even though the guide wire rotates or translates
relative to the filter element.
[0049] Once balloon 41 has dilated stenosis S, angioplasty catheter
40 is withdrawn along guide wire 11 while leaving the guide wire in
place. If desired, a stent delivery system (not shown) may be
advanced along guide wire 11 and one or more stents deployed across
the dilated stenosis to retain the patency of the dilated
vessel.
[0050] When treatment of the stenosis is completed, delivery sheath
20 (with push tube 25 removed) may again be advanced along guide
wire 11 to a position just proximal of filter element 30. Guide
wire 11 then is pulled proximally so that distal region 12 passes
through elastomeric cone 34 and bears against capture ring 36. The
lumen in cone 34 seals itself after distal region 12 passes through
it so that emboli trapped in sac 31 do not escape through the lumen
of cone 34.
[0051] When guide wire 11 is pulled further in the proximal
direction, with catheter 21 held stationary, struts 32 are forced
radially inward by the distal edge of the catheter. This in turn
causes sac 31 to disengage the vessel walls. As the guide wire
continues to be pulled proximally, struts 32 cause sac 31 to
collapse inward to its contracted position and the filter element
is retracted into lumen 24 of catheter 21. Emboli E are trapped and
retained in filter element 30 throughout treatment of the stenosis,
and are withdrawn from the vessel when the filter element is
retracted within catheter 21. Catheter 21 then is removed from the
vessel.
[0052] Referring now to FIGS. 4A and 4B, an alternative embodiment
of the filter element and guide wire of the present invention is
described. Guide wire 50 is similar in construction to guide wire
11 described with respect to FIG. 1, except that it includes flange
51 on enlarged diameter distal region 52 of guide wire 50, and
enlarged distal region 52 has length L.sub.1 that is longer than
the length of the filter element 60 in the contracted state.
[0053] Distal region 52 may be formed from a malleable material, a
coil spring, or a pliable thermoplastic material molded onto guide
wire 50, and preferably is covered with a smooth hydrophilic
coating to facilitate movement of filter element 60 as described
hereinafter. Alternatively, guide wire 50 and distal region 52 may
comprise a mechanism, such as are known in the art, for steering
distal region 52 through a patient's vasculature. Distal region 52
also may comprise a radiopaque material or may include a radiopaque
band (not shown) to assist in visualization and placement of the
guide wire.
[0054] Filter element 60 comprises self-expanding struts 61 coupled
to capture ring 62 and tubular sleeve 63. Sleeve 63 is affixed at
its distal end to funnel-shaped filter sac 64, which in turn is
coupled to distal ring 65. Capture ring 62 has bore 66 with an
inner diameter larger than the diameter of guide wire 50, but
smaller than the diameter of distal region 52. Accordingly, guide
wire 50 may freely translate and rotate through bore 66 of capture
ring 62 while the filter element remains stationary.
[0055] Distal ring 65 has bore 67 with a diameter slightly larger
than the diameter of distal region 52. This enables distal ring 65
to slide or rotate freely over distal region 52, but with minimal
clearance for emboli to escape from sac 64 through the annulus
between distal ring 65 and distal region 52. Distal region 52
includes flange 51, which has a diameter that is larger than the
diameter of bore 66 of capture ring 62. Thus, filter element 60 is
captured on guide wire 50 proximally by distal ring 65 abutting
against flange 51, and distally by capture ring 62 abutting against
flange 51.
[0056] Sleeve 63 and sac 64 filter blood passing through the
vessel, and preferably have a pore size selected to filter out
particles having a diameter greater than 0.0012 inches (30
microns). Sleeve 63 and sac 64 preferably comprise a flexible woven
metal alloy, polymer tube, or perforated fabric, and are expanded
to the deployed state, as shown in FIG. 4A, by struts 61.
Advantageously, sleeve 63 is designed so that its perimeter
conforms to the inner diameter of the vessel to seal against bypass
flow, even in curved vessels. In addition, sleeve 63 tends to
prevent skewing of the filter element and ensures that the filter
is properly oriented parallel to the axis of the vessel when the
filter element is deployed.
[0057] Filter element 60 is suitable for delivery percutaneously
and transluminally to a desired location in a vessel using delivery
sheath 20 of FIG. 1. In particular, struts 61 may be radially
compressed to collapse sleeve 63 and sac 64, as shown in FIG. 4B,
thereby permitting the filter element to be loaded into lumen 24 of
catheter 21 so that capture ring 62 abuts against distal end 27 of
push tube 25.
[0058] Deployment of filter element 60 is similar to the method
described with respect to FIGS. 3B and 3C. Specifically, delivery
sheath 20 is advanced through a vessel with distal region 52
extending beyond distal end 23 of catheter 21. Once distal region
52 has crossed the stenosis, as confirmed by fluoroscopy, push tube
25 is held place and catheter 21 is retracted proximally.
Alternatively, push tube 25 may be omitted and guide wire 50 may be
held stationary with filter element 60 held in position by flange
51. Retraction of catheter 21 uncovers filter element 60, allowing
struts 61 to expand outward and urge the perimeter of sleeve 63 and
sac 64 into engagement with the walls of the vessel.
[0059] Delivery sheath 20 then is removed, and one or more
interventional devices may be serially employed on guide wire 50.
Like the embodiment of FIG. 1, motion imparted to guide wire 50
during exchange of instruments along the guide wire causes the
guide wire to slide through filter element 60 without causing
skewing or displacement of the filter element. Advantageously, this
prevents emboli from escaping sac 64 or damage to the endothelium
caused by scraping of the filter element.
[0060] Once treatment of the stenosis is completed, the treatment
device (e.g., angioplasty catheter, etc.) is removed, and delivery
sheath 20 is again advanced along guide wire 50. When distal end 23
of catheter 21 is disposed adjacent to capture ring 62, guide wire
50 is pulled proximally. As a result of this motion, distal region
52 passes through filter element 60 until flange 51 abuts against
capture ring 62. Further proximal movement of guide wire 50 causes
struts 61 to be urged inward, collapsing sleeve 63 and sac 64 so
that they can be drawn into lumen 24 of catheter 21.
[0061] Unlike the embodiment of FIG. 1, where the distal region
passes through cone 34, length L.sub.1 is sufficiently long so that
distal ring 65 is still disposed over the enlarged diameter of
distal region 52 when the filter element is in the contracted
state. Accordingly, when filter element 60 is contracted for
removal, emboli cannot escape through bore 67 of distal ring 65,
since the bore continues to be substantially blocked by distal
region 52 of guide wire 50. Delivery sheath 20, guide wire 50 and
filter element 60 then are removed from the vessel with any emboli
trapped within the contracted filter element.
[0062] In a preferred embodiment of the apparatus of FIGS. 4, guide
wire 50 has a suitable length for transluminal percutaneous
applications and a diameter in a range of about 0.006 to 0.025
inches , and more preferably 0.012 inches. Distal region 52 of
guide wire 50 has a diameter larger than the diameter of guide wire
50, and preferably in a range of about 0.010 to 0.038 inches, more
preferably 0.018 inches.
[0063] While filter element 60 may comprise any length suitable for
an intended application, in one preferred embodiment, filter
element 60 has a deployed length of 3.5 cm and a maximum deployed
diameter of 12 mm. For this embodiment, length L.sub.1 of distal
region 52 preferably is 5.0 cm. For a guide wire having a diameter
of 0.012 inches and distal region having a diameter of 0.018
inches, capture ring 62 preferably has an inner diameter of 0.014
inches and an outer diameter of 0.018 inches. In this case distal
ring 65 preferably has an inner diameter of 0.0181 inches and an
outer diameter of 0.024 inches.
[0064] Referring now to FIGS. 5, apparatus 90 of an alternative
embodiment of the present invention comprises guide wire 100 and
filter element 102. Filter element 102 preferably is constructed in
accordance with filter element 30 of FIGS. 1-3. Specifically,
filter element 102 comprises funnel-shaped filter sac 105 coupled
to plurality of self-expanding struts 103 at a proximal end and
elastomeric cone 106 at a distal end. Struts 103 are affixed to
capture ring 104, as described in detail hereinabove with respect
to FIGS. 2. Optionally, filter element 102 also may comprise
cylindrical sleeve 63, as described hereinabove with respect to
FIGS. 4, disposed between struts 103 and sac 105.
[0065] Guide wire 100 comprises proximal stop 110 and distal region
112. Distal region 112 serves as a distal stop that limits the
distal movement of filter element 102 along guide wire 100, as
described hereinabove. Proximal stop 110 has proximal and distal
ends 114 and 115 and taper 111 disposed therebetween, as shown in
FIG. 5A. Taper 111 of guide wire 110 spans from proximal end 114,
which preferably has a guide wire diameter of about 0.018 inches,
to distal end 115, which preferably has an enlarged diameter of
about 0.022 inches. Proximal stop 110 and distal region 112 are
spaced apart such a distance that filter element 102, when deployed
therebetween, will not be disturbed by incidental longitudinal
movements of guide wire 100.
[0066] Apparatus 90 of FIGS. 5 preferably is deployed in the manner
described hereinabove with respect to apparatus 10 of FIGS. 1-3,
except as noted below. In a first step, guide wire 100 is
percutaneously and transluminally inserted into treatment vessel V
under fluoroscopy, with proximal stop 110 preferably being disposed
just distal of stenosis S. In a next step, filter element 102 is
advanced along guide wire 100 in a contracted state, preferably
being contracted within lumen 24 of catheter 21, as described
hereinabove with respect to FIG. 3B. Push tube 25 of FIG. 3B then
is advanced distally so that a distal end of push tube 25 abuts
capture ring 104 and advances filter element 102 distally over
guide wire 100.
[0067] As push tube 25 advances filter element 102, elastomeric
cone 106 is pushed distally over proximal stop 110 of guide wire
100. Elastomeric cone 106 is configured to be flexible enough to
radially expand over the enlarged diameter of distal end 115 of
proximal stop 110. After being advanced over distal end 115,
elastomeric cone 106 then substantially seals itself about guide
wire 100 to prevent emboli from subsequently escaping when a
medical procedure is performed.
[0068] As push tube 25 further is advanced, capture ring 104 then
is advanced over proximal stop 110. Capture ring 104 also is
compliant enough to expand over the enlarged diameter of distal end
115 when advanced distally, and then substantially seals itself
about guide wire 100 after it passes over proximal stop 110. Once
filter element 102 is disposed between proximal stop 110 and distal
region 112, filter element 102 is deployed, e.g., by proximally
retracting catheter 21 while holding push tube 25 stationary. The
catheter and push tube then may be removed from the patient's
vessel.
[0069] Once deployed, filter element 102 preferably is provided in
a central position between proximal stop 110 and distal region 112,
as depicted in FIG. 5A, either by proximally retracting or distally
advancing guide wire 100 under fluoroscopy. In this central
position, incidental movements of guide wire 100 will not
substantially disturb filter element 102.
[0070] If it becomes necessary to advance filter element 102
distally during the medical procedure, guide wire 100 may be
advanced distally by a physician until distal end 115 of proximal
stop 110 abuts capture ring 104 and gently urges filter element 102
distally, as shown in FIG. 5B. Advantageously, this enables filter
element 102 to be advanced distally without having to remove
angioplasty or stenting apparatus, then having to advance a push
tube over then length of guide wire 100. Upon repositioning of
filter element 102, guide wire 100 preferably is repositioned to
the central position depicted in FIG. 5A, so that incidental
movements of guide wire 100 do not disturb filter element 102.
[0071] When treatment of the stenosis is completed and any emboli
are captured within sac 105 of filter element 102, delivery sheath
20 (with push tube 25 removed) may be advanced to a location just
proximal of filter element 102. Guide wire 100 then is retracted
proximally so that distal region 112 passes through elastomeric
cone 106 and bears against capture ring 104, as described
hereinabove with respect to FIG. 3E. A lumen of cone 106 seals
itself after distal region 112 passes through to prevent emboli
from escaping downstream. Distal region 112 then abuts capture ring
104 and pulls filter element 102 in a proximal direction. With the
catheter held stationary, struts 103 are forced radially inward by
the distal edge of the catheter to cause filter element 102 and any
emboli captured therein to be removed via the catheter.
[0072] Advantageously, the one-way stop feature of proximal stop
110 allows guide wire 100 to be advanced through a patient's
vasculature without having filter element 102 disposed on the guide
wire. This facilitates advancement of guide wire 100 through a
patient's tortuous vasculature. Then, when guide wire 100 is
properly positioned in a vessel unencumbered, filter element 102
may be advanced distally over proximal stop 110, and securely
positioned between proximal stop 110 and distal region 112 during
the medical procedure.
[0073] Referring now to FIGS. 6, an alternative embodiment of
proximal stop 110 of the embodiment of FIGS. 5 is described. In
FIG. 6A, guide wire 120 preferably is provided substantially in
accordance with guide wire 11 of FIG. 1, and comprises enlarged
diameter distal region 122, which acts as a distal stop to limit
travel of filter element 102 in the distal direction, as described
hereinabove. Guide wire 120 further comprises proximal stop 130,
which includes at least one depressible tab 131 having proximal end
133 and distal end 134, as shown in FIGS. 6B-6C.
[0074] Proximal end 133 of depressible tab 131 is affixed to guide
wire 120, e.g., using a solder, while distal end 134 is biased to
extend slightly radially outward from guide wire 120 in a relaxed
state, as shown in FIG. 6B. Depressible tab 131 may comprise a
slight concave curvature to cause distal end 134 to be biased
radially outward or, alternatively, proximal end 133 may be affixed
to guide wire 120 in such a manner that allows distal end 134 to be
biased radially outward in the relaxed state.
[0075] Depressible tab 131 is flexible so that it may be
transformed between the relaxed state, shown in FIG. 6B, and a
contracted state, as shown in FIG. 6C. In the contracted state,
external compressive forces cause depressible tab 131 to be
substantially flush with an exterior surface of guide wire 120.
Guide wire 120 optionally may comprise a shallow slot (not shown)
disposed in a lateral surface that is adapted to receive
depressible tab 131 in the contracted state. When depressible tab
131 is contracted, as shown in FIG. 6C, the shallow slot serves to
ensure that depressible tab 131 does not extend radially beyond
guide wire 120.
[0076] Apparatus 110 of FIGS. 6 preferably is deployed in the
manner described hereinabove with respect to apparatus 10 of FIGS.
1-3, except as noted below. In a first step, guide wire 120 is
percutaneously and transluminally inserted until proximal stop 130
is disposed just distal of a stenosis. In a next step, filter
element 102 is advanced along guide wire 120 in a contracted state,
preferably being contracted within lumen 24 of catheter 21, as
described hereinabove with respect to FIG. 3B. Push tube 25 of FIG.
3B then is advanced distally so that a distal end of push tube 25
abuts capture ring 104 and advances filter element 102
distally.
[0077] As push tube 25 advances filter element 102, elastomeric
cone 106 is pushed distally over proximal stop 130. Depressible tab
131 assumes the contracted state, depicted in FIG. 6C, as filter
element 102 is advanced distally to facilitate advancement of
elastomeric cone 106 over proximal stop 130. Elastomeric cone 106
also may radially expand over proximal stop 130, if necessary, and
then substantially seal itself about guide wire 120 after it passes
over proximal stop 130. As push tube 25 further is advanced,
capture ring 104 then is advanced over proximal stop 130 in the
same manner as elastomeric cone 106.
[0078] After elastomeric cone 106 and capture ring 104 are advanced
distally over proximal stop 130, depressible tab 131 returns to the
relaxed state, depicted in FIG. 6B. Filter element 102 then is
deployed between proximal stop 130 and distal region 122, e.g., by
proximally retracting catheter 21 while holding push tube 25
stationary. The catheter and push tube then may be removed from the
patient's vessel.
[0079] Once deployed, filter element 102 preferably is provided in
a central position between proximal stop 130 and distal region 122
by proximally retracting or distally advancing guide wire 120 under
fluoroscopy. If it becomes necessary to advance filter element 102
distally during a medical procedure, guide wire 120 may be advanced
distally to cause distal end 134 of depressible tab 131 to abut
capture ring 104 and gently urge filter element 102 distally. Upon
completion of the medical procedure, catheter 21 may be advanced
distally over guide wire 120 to cause filter element 102 and any
emboli captured therein to be removed via the catheter, as
described in detail hereinabove with respect to FIG. 3E.
[0080] Referring now to FIGS. 7, a further alternative embodiment
of the present invention is described, whereby guide wire 11 of
FIG. 1 is slightly bent to comprise a one-way proximal stop
mechanism. Guide wire 150 of FIG. 7A comprises enlarged diameter
distal region 152, which acts as a distal stop to limit travel of
filter element 102 in the distal direction. Guide wire 150 further
comprises proximal stop 160, which includes bent section 161 of
guide wire 150 having proximal taper 163 and distal taper 164.
Proximal taper 163 comprises angle a with respect to longitudinal
axis 170 of guide wire 150, while distal taper 164 comprises angle
.beta. with respect to longitudinal axis 170, as depicted in FIG.
7B.
[0081] Proximal stop 160 is configured to facilitate distal
advancement of filter element 102 over bent section 161 of guide
wire 150 via proximal taper 163, while inhibiting movement of
filter element 102 in a proximal direction over bent section 161
via distal taper 164. In a preferred embodiment, angle .beta. is
greater than angle .alpha., as illustratively shown in FIG. 7B, to
permit advancement of filter element 102 in a distal direction
only.
[0082] Proximal stop 160 of guide wire 150 is flexible enough so
that proximal and distal tapers 163 and 164 may assume
substantially flat configurations, i.e., substantially parallel to
longitudinal axis 170 of guide wire 150, when elastomeric cone 106
and capture ring 104 are advanced distally over bent region 161.
Once filter element 102 is advanced distally over proximal stop
160, proximal and distal tapers 163 and 164 return to the bent
configurations depicted in FIG. 7A.
[0083] Apparatus 140 of FIGS. 7 preferably is deployed in the
manner described hereinabove with respect to apparatus 10 of FIGS.
1-3, except as noted below. In a first step, guide wire 150 is
percutaneously and transluminally inserted until proximal stop 160
is disposed just distal of a stenosis. In a next step, filter
element 102 is advanced along guide wire 150 in a contracted state,
preferably being contracted within lumen 24 of catheter 21, as
described hereinabove with respect to FIG. 3B. Push tube 25 of FIG.
3B then is advanced distally so that a distal end of push tube 25
abuts capture ring 104 and advances filter element 102
distally.
[0084] As push tube 25 advances filter element 102, elastomeric
cone 106 is pushed distally over proximal taper 163 of guide wire
150. Proximal and distal tapers 163 and 164 may assume
substantially flat configurations, i.e., substantially parallel to
longitudinal axis 170, to facilitate distal advancement of
elastomeric cone 106. As push tube 25 further is advanced distally,
capture ring 104 then is advanced over proximal stop 160 in the
same manner as elastomeric cone 106.
[0085] Once filter element 102 is disposed between proximal stop
160 and distal region 152, filter element 102 is deployed, as
described hereinabove. Filter element 102 preferably is provided in
a central position between proximal stop 160 and distal region 152,
as shown in FIG. 7A, by proximally retracting or distally advancing
guide wire 150 under fluoroscopy. If it becomes necessary to
advance filter element 102 distally during a medical procedure,
guide wire 150 may be advanced distally until distal taper 164 of
proximal stop 160 abuts capture ring 104 and gently urges filter
element 102 distally. Proximal stop 160 of guide wire 150 is
configured to retain the bent shape depicted in FIGS. 7 as distal
taper 164 urges filter element 102 distally. Upon completion of the
medical procedure, catheter 21 may be advanced distally over guide
wire 150 to cause filter element 102 and any emboli captured
therein to be removed via the catheter, as described in detail
hereinabove with respect to FIG. 3E.
[0086] While preferred illustrative embodiments of the invention
are described above, it will be apparent to one skilled in the art
that various changes and modifications may be made. The appended
claims are intended to cover all such changes and modifications
that fall within the true spirit and scope of the invention.
* * * * *