U.S. patent application number 11/115418 was filed with the patent office on 2006-04-06 for embolic protection system.
Invention is credited to Eamon Brady, Paul Gilson, Patrick Grirrin, John Nielan, Charles Taylor, David Vale.
Application Number | 20060074446 11/115418 |
Document ID | / |
Family ID | 38814537 |
Filed Date | 2006-04-06 |
United States Patent
Application |
20060074446 |
Kind Code |
A1 |
Gilson; Paul ; et
al. |
April 6, 2006 |
Embolic protection system
Abstract
An embolic protection system 1 comprises a guidewire 99 for
advancing through a vasculature, the guidewire 99 having a distal
end and a proximal end; an embolic protection filter 1 having a
filter body 41 with a distal end and a proximal end, the filter
body 41 providing for a collapsed configuration and an expanded
deployed configuration. The embolic protection filter body 41 has a
guidewire path for slidably receiving the guidewire 99 to permit
movement of the filter 1 relative to the guidewire 99 when the
filter 1 is in the collapsed configuration and the expanded
deployed configuration. A delivery catheter 2 is advanceable over
the guidewire 99 for delivery of the embolic protection filter 1;
the delivery catheter 2 having a proximal end and a distal end. The
filter 1 is deployed from the distal end of the delivery catheter 2
into the expanded deployed configuration. A retrieval catheter 3 is
also advancable over the guidewire 99 for retrieval of the filter
1, the retrieval catheter 3 having a distal end and a proximal end;
and engagement elements for engaging the embolic protection filter
1 with the guidewire 99 for retrieval of the filter 1 into the
retrieval catheter 3 in the collapsed configuration.
Inventors: |
Gilson; Paul; (Moycullen,
IE) ; Taylor; Charles; (West Sussex, GB) ;
Grirrin; Patrick; (Castlegar, IE) ; Nielan; John;
(Gort, IE) ; Vale; David; (Clontarf, IE) ;
Brady; Eamon; (Elphin, IE) |
Correspondence
Address: |
SUGHRUE MION, PLLC
2100 PENNSYLVANIA AVENUE, N.W.
SUITE 800
WASHINGTON
DC
20037
US
|
Family ID: |
38814537 |
Appl. No.: |
11/115418 |
Filed: |
April 27, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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|
09838545 |
Apr 20, 2001 |
|
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|
11115418 |
Apr 27, 2005 |
|
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09188472 |
Nov 9, 1998 |
6336934 |
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09838545 |
Apr 20, 2001 |
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Current U.S.
Class: |
606/200 |
Current CPC
Class: |
A61F 2/9522 20200501;
A61F 2230/0006 20130101; A61F 2002/015 20130101; A61F 2230/0067
20130101; A61F 2/0095 20130101; A61F 2002/018 20130101; A61F 2/013
20130101; A61B 17/221 20130101; A61F 2/011 20200501 |
Class at
Publication: |
606/200 |
International
Class: |
A61M 29/00 20060101
A61M029/00 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 8, 1998 |
IE |
980267 |
Nov 7, 1997 |
IE |
970789 |
Apr 20, 2000 |
WO |
PCT/IE00/00045 |
Mar 16, 2001 |
IE |
2001/0255 |
Mar 16, 2001 |
IE |
2001/0256 |
Mar 16, 2001 |
IE |
2001/0259 |
Mar 16, 2001 |
IE |
2001/0263 |
Claims
1-67. (canceled)
68. Apparatus for filtering emboli from blood flowing through a
vessel, the apparatus comprising: a guide wire having a distal
region and a docking member rigidly coupled to the distal region; a
distal cone disposed for translation on the guide wire, the docking
member limiting translation of the distal cone in a distal
direction; and a filter sac connected to the distal cone, wherein
the distal cone can be removably coupled to the docking member.
69. The apparatus of claim 68 wherein, when the filter sac is
deployed in the vessel, rotation or distal translation of the guide
wire relative to the distal cone does not displace the filter sac,
but retraction of the guide wire in a proximal direction causes the
docking member to abut against the distal cone.
70. The apparatus of claim 68 wherein the docking member contains a
grove and the distal cone contains a locking ring sized for
insertion into the grove.
71. Apparatus for filtering emboli from blood flowing through a
vessel, the apparatus comprising: a guide wire having a first
portion having a first diameter and a distal region having a second
diameter greater than the first diameter; and a filter element
having a distal cone disposed for translation on the first portion,
the distal cone having an aperture greater than the first diameter
but smaller than the second diameter, wherein rotation or distal
translation of the guide wire relative to the distal cone does not
displace the filter element, and distal cone can be removably
coupled to the docking member.
72. The apparatus of claim 71 wherein the guide wire further
comprises a flange disposed on the distal region having a diameter
larger than the diameter of the aperture in the distal cone.
73. Apparatus for filtering emboli during treatment of occlusive
disease in a vessel, the apparatus comprising: a guide wire having
a first diameter and a distal region having a second diameter
greater than the first diameter; a filter element having a sac
coupled to a distal cone, the distal cone having an aperture
greater than the first diameter but smaller than the second
diameter, wherein the filter element is disposed on the guide wire
and the guide wire extends through the aperture with the distal
region disposed distally of the distal cone, so that when the
filter element is deployed in the vessel, rotation or distal
translation of the guide wire does not displace the filter element,
but retraction of the guide wire in a proximal direction causes the
distal region to abut against the distal cone, and wherein the
distal cone can be removably coupled to the docking member.
74. A method of filtering emboli from blood flowing through a
vessel, the method comprising: providing a guide wire having a
distal region including a docking member, and a filter element
having a distal cone disposed for translation on the guide wire
proximal of the docking member, wherein the distal cone can be
removably coupled to the docking member; transluminally inserting
the guide wire and filter element into a vessel; deploying the
filter element to engage a wall of the vessel, the filter element
filtering emboli out of blood flowing through the vessel; advancing
a treatment device along the guide wire to treat a portion of the
vessel proximal to the location of the filter element, rotation or
distal translation of the guide wire relative to the filter element
imparted by the treatment device not displacing the filter
element.
75. The method of claim 74 wherein: the docking member contains a
grove and the distal cone contains a locking ring sized for
insertion into the grove; and the locking ring of the distal cone
is inserted into the grove of the docking member until the locking
ring is wholly within the grove.
76. The method of claim 74 further comprising: providing a delivery
sheath; and compressing the filter element to a contracted state to
insert the filter element within the delivery sheath.
77. The method of claim 76 wherein the filter element comprises an
expandable sac, and deploying the filter element comprises
expanding the expandable sac so that a perimeter of the expandable
sac contacts the wall of the vessel.
78. Apparatus for filtering emboli from blood flowing through a
vessel, the apparatus comprising: a guide wire having a distal
region; a filter element disposed for rotation on the distal region
of the guide wire, the filter element comprising a self-expanding
strut and a filter sac connected to the self-expanding strut; and a
docking member rigidly coupled to the distal region distal to the
filter element, the docking member limiting distal translation of
the filter element on the guide wire, wherein the filter element
can be removably coupled to the docking member.
79. The apparatus of claim 78 wherein, when the filter sac is
deployed in the vessel, rotation of the guide wire does not
displace the filter element.
80. The apparatus of claim 78 wherein the docking member contains a
groove and the filter element contains a locking ring sized for
insertion into the groove.
81. A method of filtering emboli from blood flowing through a
vessel, the method comprising: providing a guide wire having a
distal region including a docking member rigidly coupled to the
distal region, and a filter element disposed for translation on the
guide wire proximal to the docking member, the filter element
comprising a plurality of self-expanding struts having a filter sac
affixed thereto, wherein the filter element can be removably
coupled to the docking member; transluminally inserting the guide
wire and filter element into a vessel; deploying the filter element
so that the struts and filter sac expand to engage a wall of the
vessel, the filter sac filtering emboli out of blood flowing
through the vessel; and advancing a treatment device along the
guide wire to treat a portion of the vessel proximal to the
location of the filter element, rotation or distal translation of
the guide wire relative to the filter element imparted by the
treatment device not displacing the filter element.
82. The method of claim 81 further comprising retracting the guide
wire in a proximal direction to cause the docking member to abut
against the filter element.
83. The method of claim 81 wherein the docking member contains a
groove and the filter element contains a locking ring sized for
insertion into the groove.
84. The method of claim 81 further comprising: providing a
retrieval catheter having a recovery sock; advancing the retrieval
catheter over the guide wire until the recovery sock covers a mouth
of the filter element; and urging the retrieval catheter against
the self-expanding struts of the filter element to cause the filter
element to collapse.
Description
INTRODUCTION
[0001] This invention relates to a transvascular embolic protection
system for safely capturing and retaining embolic material released
during an interventional procedure while maintaining blood
flow.
[0002] WO-A-99/23976 describes various embolic protection systems
of this type. WO-A-99/51167 and WO-A-99/51166 describe delivery
catheters for delivery of an embolic protection filter to a desired
site in the vascular system. Various embolic filters are described
in WO-A-00/67668), WO-A-00/67669 WO-A-00/67670 and WO-A-00/67671. A
retrieval catheter for use with such embolic protection systems is
described in WO-A-01/12082.
[0003] There is an economical and clinical need to provide an
improved embolic protection system which will be easy and
convenient for a clinician to prepare for use, to deploy and to
retrieve. In addition there is a need to provide such a system
which will facilitate a wide range of clinical procedures to be
carried out.
STATEMENTS OF INVENTION
[0004] According to the invention there is provided an embolic
protection system comprising:-- [0005] a guidewire for advancing
through a vasculature, the guidewire having a distal end and a
proximal end; [0006] an embolic protection filter having a filter
body with a distal end and a proximal end, the filter body
providing for a collapsed configuration and an expanded deployed
configuration; [0007] the embolic protection filter body having a
guidewire path for slidably receiving the guidewire to permit
movement of the filter relative to the guidewire when the filter is
in the collapsed configuration and the expanded deployed
configuration; [0008] a delivery catheter advanceable over the
guidewire for delivery of the embolic protection filter; the
delivery catheter having a proximal end and a distal end, the
filter being deployed from the distal end of the delivery catheter
into the expanded deployed configuration; [0009] a retrieval
catheter advancable over the guidewire for retrieval of the filter,
the retrieval catheter having a distal end and a proximal end; and
[0010] engagement elements for engaging the embolic protection
filter with the guidewire for retrieval of the filter into the
retrieval catheter in the collapsed configuration.
[0011] In one embodiment of the invention the guidewire path is in
isolation from the embolic material captured within the filter
body.
[0012] In a preferred case the tubular guidewire path is defined by
a tubular sleeve. Ideally the tubular sleeve extends from the
proximal end to the distal end of the filter. Desirably the
guidewire path is a tubular guidewire path.
[0013] In another embodiment the engagement elements comprise a
guidewire engagement element on the guidewire and a filter
engagement element on the filter, the engagement elements
co-operating to provide selective engagement and positioning of the
filter with respect to the guidewire. Preferably the engagement
element of the guidewire comprises a guidewire abutment on the
guidewire.
[0014] The guidewire abutment may be located at the distal end of
the guidewire.
[0015] The guidewire abutment may be located proximal of the distal
and of the guidewire.
[0016] In a particularly preferred embodiment the engagement
element of the filter comprises a filter abutment on the
filter.
[0017] The filter abutment may be a distal abutment on the
filter.
[0018] The filter abutment may be a proximal abutment on the
filter.
[0019] Most preferably the tubular guidewire path is defined by a
sleeve and the filter abutment is provided by the sleeve.
[0020] In another embodiment of the invention the engagement
elements comprise releasable locking elements. Preferably the
releasable locking elements comprise a taper lock. Ideally the
guidewire engagement element comprises a locking ring on the
guidewire and the filter engagement element comprises a tapered
surface of the filter, the locking ring having a tapered surface
which is engageable with the tapered surface of the filter to lock
the filter to the guidewire. Most preferably the locking ring is a
split ring.
[0021] In another case the embolic protection system includes a
tube advancable over the guidewire, the locking ring being located
between a distal end of the tube and the filter for retrieval of
the filter.
[0022] Desirably the releasable locking means includes a tether
engageable with the filter for retrieving the filter into the
retrieval catheter.
[0023] In a preferred embodiment the embolic protection system
comprises deployment means for moving the collapsed filter relative
to the distal end of the delivery catheter. Preferably the
deployment means comprises a tube which is advancable over the
guidewire for engagement with the proximal end of the filter, the
tube being movable longitudinally relative to the delivery catheter
for deployment of the filter from the distal end of the delivery
catheter.
[0024] In another embodiment the embolic protection system includes
loading means for loading the filter into the delivery catheter.
Ideally the loading means comprises a funnel having a narrowed
portion disposed at the distal end of the delivery catheter and an
enlarged portion for receiving a proximal portion of the filter in
the expanded configuration, the filter being progressively
collapsed as it is moved through the funnel for loading into the
delivery catheter.
[0025] In a further embodiment the embolic protection system
includes engagement means for engaging the filter within the
retrieval catheter. Preferably the engagement means comprises a
frictional engagement between the filter body and an internal
surface of the distal end of the retrieval catheter. Most
preferably the engagement means comprises projections on the inner
surface of the retrieval catheter adjacent the distal end
thereof.
[0026] In another preferred embodiment the delivery catheter
includes an elongate slot disposed in a first sidewall thereof at a
first distal location which is spaced a relatively longer distance
from the proximal end of the delivery catheter than from the distal
end of the delivery catheter, and wherein the inner deployment
catheter includes an aperture disposed in a second sidewall thereof
at a second distal location which substantially corresponds with
said first distal location for said elongate slot, thereby
permitting co-operative movement of said filter with respect to
said guidewire and associated delivery and deployment catheters for
selective deployment of the filter while facilitating the rapid
exchange of said catheter and filter assembly over a guidewire
without the utilisation of exchange wires or extension wires.
[0027] The embolic protection filter may comprise a collapsible
filter body, the proximal inlet end of the filter body having one
or more inlet openings sized to allow blood and embolic material
enter the filter body, the distal outlet end of the filter body
having a plurality of outlet openings sized to allow through
passage of blood but to retain undesired embolic material within
the filter body. Ideally the filter comprises a collapsible filter
support frame having a proximal end and a distal end, the filter
support frame being movable between a collapsed position for
movement during delivery through the vascular system and an
extended outwardly projecting position to support the filter body
in an expanded position thereby urging the filter body into
apposition with the vasculature upon deployment. Most preferably
the embolic protection system comprises a guide olive provided at
the distal end of the filter body.
[0028] Desirably the embolic protection system comprises an inner
elongate sleeve to which the filter body and the filter support
frame are mounted, the sleeve having a proximal end and a distal
end, the guide olive extending distally of the sleeve distal
end.
[0029] the proximal end of the filter support frame and the inlet
end of the filter body are preferably attached to the proximal end
of the sleeve.
[0030] The guide olive may be integral with the filter body.
[0031] Ideally the guide olive tapers distally inwardly.
[0032] In another aspect the invention provides a method for the
capture and removal of embolic material from a blood vessel during
an interventional procedure comprising the steps of:-- [0033]
advancing a guidewire through a vasculature; [0034] crossing a
desired treatment location with the guidewire; [0035] introducing
over the guidewire a collapsible embolic protection filter having a
collapsed configuration, the collapsed configuration permitting
delivery and withdrawal of the filter; [0036] deploying the filter
distal to the treatment location; [0037] carrying out the
interventional procedure, embolic material generated during the
treatment procedure being captured by the deployed filter; [0038]
advancing a retrieval catheter over the guidewire; [0039]
collapsing the filter into the retrieval catheter and with it the
captured embolic material; [0040] withdrawing the retrieval
catheter and the collapsed filter from the vasculature leaving the
guidewire in the vasculature.
[0041] In one embodiment of the invention the method comprises the
step of providing a catheter over the guidewire after withdrawal of
the retrieval catheter.
[0042] In another embodiment the method includes the step of moving
the guidewire after withdrawal of the retrieval catheter and the
collapsed filter from the vasculature to re-position the guidewire
in the vasculature.
[0043] The catheter may be a catheter for delivery of a diagnostic
medium.
[0044] The catheter may be a catheter for delivery of a lytic
agent.
[0045] The filter is preferably slidably disposed on the guidewire
when the filter is in the expanded deployed configuration.
[0046] In one preferred case the filter is rotatably disposed on
the guidewire when the filter is in the expanded deployed
configuration.
[0047] In a further embodiment the method includes the steps of:--
[0048] loading the filter in a collapsed configuration within a
delivery catheter; [0049] advancing the delivery catheter and
filter over the guidewire to deliver the filter to a desired
location; and [0050] deploying the filter from the delivery
catheter at the desired location.
[0051] Preferably the method includes the steps of:-- [0052]
collapsing the filter from an expanded configuration for loading
the filter into the delivery catheter; [0053] the filter being
expanded to a deployment configuration on release from the delivery
catheter.
[0054] The treatment location may be a region of stenosis.
[0055] In one embodiment the interventional procedure includes a
balloon dilation of the stenosis while the filter is deployed.
[0056] In another embodiment the interventional procedure includes
a stenting of the treatment location while the filter is
deployed.
[0057] According to another aspect of the invention there is
provided a medical catheter for transvascular delivery and
deployment of an embolic protection filter, the catheter
comprising:-- [0058] an outer catheter tube defining a distal end;
and [0059] an inner catheter tube defining a distal end; [0060] the
outer tube being at least partially movable relative to the inner
tube between a delivery configuration in which the distal end of
the outer tube extends distally of the distal end of the inner tube
to define a reception space for an embolic protection filter within
the outer tube, and a deployment configuration in which the distal
end of the inner tube extends distally of the distal end of the
outer tube for deployment of the embolic protection filter; [0061]
the inner catheter tube providing compressive resistance and the
outer catheter tube providing stretch resistance.
[0062] In one embodiment the inner catheter tube at least partially
comprises a relatively stiff core encased in a more pliable
body.
[0063] In another embodiment the outer catheter tube at least
partially comprises a relatively stiff core encased in a more
pliable body.
[0064] The core is preferably oriented to prevent elongation of the
outer catheter tube and/or compression of the inner catheter
tube.
[0065] The core may comprise a mesh.
[0066] In one case the core comprises a plurality of longitudinally
oriented strips of a stiff material. In another case the core
comprises a plurality of circumferentially oriented strips of a
stiff material.
[0067] The core may be of a metallic material. The metal is
preferably stainless steel.
[0068] The pliable body may be of a plastics material. The plastic
is preferably polyamide.
[0069] In a further aspect the invention provides an embolic
protection device comprising: [0070] a collapsible filter element
for delivery through a vascular system of a patient; [0071] the
filter element comprising a collapsible filter body and a
collapsible filter support frame contacting the filter body; [0072]
the filter body having an inlet end and an outlet end, the inlet
end of the filter body having one or more inlet openings sized to
allow blood and embolic material enter the filter body, the outlet
end of the filter body having a plurality of outlet openings sized
to allow through passage of blood but to retain undesired embolic
material within the filter body; [0073] the filter support frame
being movable between a collapsed position for movement through the
vascular system and an extended outwardly projecting position to
support the filter body in an expanded position; [0074] the frame
having an intermediate section to urge the filter body in the
expanded position into apposition with a vessel wall, and a
proximal section extending radially inwardly of the intermediate
section; [0075] at least part of the proximal section of the frame
being spaced distally to accommodate inflow of embolic material
through the inlet openings in the expanded position.
[0076] In one embodiment of the invention the filter body comprises
one or more linking webs between adjacent inlet openings, and a
part of the proximal section of the frame extends radially inwardly
in alignment with the webs.
[0077] The frame proximal section preferably comprises one or more
frame elements, at least one frame element providing the part of
the proximal section spaced distally. Ideally at least one frame
element provides the part of the proximal section extending
radially inwardly in alignment with a linking web between adjacent
inlet openings. Most preferably the number of frame elements is
four, two frame elements extending radially inwardly in alignment
with two webs between two inlet openings, and two frame elements
spaced distally of the inlet openings.
[0078] Desirably the support frame is gold-plated and
electropolished.
[0079] According to the invention there is also provided an
assembly for loading a collapsible embolic protection filter into a
catheter, the assembly comprising: -- [0080] a catheter defining a
reception space at a distal end of the catheter for receiving a
collapsed embolic protection filter; [0081] a separate removable
pushing device for delivering the medical device into the reception
space.
[0082] In one embodiment the assembly comprises a separate loading
device to collapse the embolic protection filter, the loading
device defining an inlet end and an outlet end, the outlet end
being configured for co-operative alignment with the reception
space.
[0083] The pushing device may comprises a proximal stop for
engagement with the embolic protection filter. Preferably the
pushing device comprises a stem, the stem having a distal stop for
engaging the embolic protection filter. Ideally the pushing device
comprises a handle.
[0084] In another embodiment the loading device comprises means for
radially compressing the embolic protection filter.
[0085] the loading device preferably comprises a funnel, the inlet
end defining a larger cross sectional area than the outlet end.
Ideally the loading device comprises a main support having a
funnel-shaped bore formed from a frusto-conical embolic protection
filter receiving portion terminating in a cylindrical portion
formed by a loading tube projecting from the main support for
alignment with the reception space before loading.
[0086] The cone angle of the funnel is preferably between
15.degree. and 65.degree.. Most preferably the cone angle is
between 35.degree. and 45.degree..
[0087] In a preferred embodiment of the invention the loading
device extends into the reception space.
[0088] In another preferred embodiment of the invention the loading
device extends around the outside of the reception space.
[0089] In a further embodiment the assembly comprises a tray, the
tray comprising a first retaining means for releasably supporting
the pushing device in a disengaged position before delivering the
embolic protection filter into the catheter. Preferably the
assembly comprises a second retaining means for releasably
supporting the loading device in co-operative alignment with the
catheter during loading.
[0090] The retaining means may comprises a channel for receiving
the loading device and/or the catheter and/or the pushing device,
and at least one projection on the channel wall projecting inwardly
for snap retention of the loading device and/or the catheter and/or
the pushing device.
[0091] Ideally the tray comprises a liquid retaining bath formed by
a recess in the tray, the bath having a depth sufficient to
accommodate in a totally submerged state the reception space of the
catheter and the embolic protection device for submerged loading of
the embolic protection filter into the reception space.
[0092] The tray preferably has a catheter holding channel
communicating with the bath, the channel defining a pathway around
the tray which supports the catheter in a loading position on the
tray.
[0093] In another embodiment means for securing the catheter within
the channel comprises a number of retainers spaced-apart along the
channel, each retainer comprising two or more associated
projections which project inwardly from opposite side walls of the
channel adjacent a mouth of the channel, the projections being
resiliently deformable for snap engagement of the catheter within
the channel behind the projections.
[0094] A ramp may be provided at an end of the channel
communicating with the bath to direct the reception space of the
catheter towards a bottom of the bath.
[0095] Ideally means is provided within the bath for supporting the
reception space of the catheter above the bottom of the bath.
[0096] Said supporting means is preferably a step adjacent the
channel.
[0097] The first retaining means may be provided within the
bath.
[0098] Desirably the assembly comprises a flushing means. Most
preferably the flushing means comprises a syringe.
[0099] In a further aspect of the invention there is provided a
method of loading an embolic protection filter into a catheter, the
method comprising the steps of:-- [0100] providing an embolic
protection filter, the embolic protection device being collapsible;
[0101] providing a embolic protection catheter defining a reception
space at a distal end of the catheter for receiving the collapsed
embolic protection filter; [0102] providing a pushing device for
delivering the embolic protection filter into the reception space;
[0103] delivering the embolic protection filter into the reception
space using the pushing device; and [0104] removing the pushing
device from the reception space.
[0105] In one embodiment the method comprises the steps of: [0106]
providing a loading device to collapse the embolic protection
filter, the loading device defining an inlet end and an outlet end;
[0107] aligning the outlet end of the loading device in
co-operation with the reception space; and [0108] delivering the
embolic protection filter through the inlet end of the loading
device and into the reception space.
[0109] In a preferred case the catheter comprises an internal
proximal stop, and the method comprises the step of moving the
collapsed embolic protection filter proximally in the reception
space using the pushing device to engage the internal proximal stop
and disassociate the loaded catheter from the loading device before
removing the pushing device.
[0110] The catheter may be constrained relative to the loading
device before delivery of the embolic protection filter through the
loading device into the reception space, and the method comprises
the step of releasing the constraint to facilitate disassociation
of the loaded catheter from the loading device.
[0111] In another embodiment the pushing device comprises a wire
for threading through the embolic protection filter, the wire
defining a distal stop for engaging the embolic protection
filter.
[0112] The loading device may comprise an elongate neck at the
outlet end, and the method comprises the step of at least partially
positioning the elongate neck in the reception space before
delivering the embolic protection filter into the reception
space.
[0113] In a preferred embodiment the method comprises the step of
flushing the embolic protection filter before delivering the
embolic protection filter into the reception space.
[0114] Ideally the method comprises the step of flushing the
catheter before delivering the embolic protection filter into the
reception space.
[0115] In a preferred case the catheter comprises an outer catheter
tube and an inner catheter tube, the inner catheter tube defining
the internal proximal stop.
[0116] Desirably both the inner catheter tube and the outer
catheter tube are flushed before delivering the embolic protection
filter through the loading device.
[0117] In another aspect the invention provides a method of loading
an embolic protection filter into a catheter, the method comprising
the steps of: -- [0118] providing a embolic protection filter, the
embolic protection filter being collapsible; [0119] providing a
catheter defining a reception space at a distal end of the catheter
for receiving the collapsed embolic protection filter, the catheter
comprising at least one internal proximal stop; [0120] providing a
loading device to collapse the embolic protection filter, the
loading device defining an inlet end and an outlet end; [0121]
aligning the outlet end of the loading device with the reception
space; [0122] delivering the embolic protection filter through the
loading device and into the reception space; and [0123] moving the
collapsed embolic protection filter towards its proximal end in the
reception space to engage said at least one the internal proximal
stop and disassociate the loaded catheter from the loading
device.
[0124] In one embodiment the method comprises the steps of:--
[0125] providing a pushing device for delivering the embolic
protection filter through the loading device and into the reception
space, and for engaging the collapsed embolic protection filter
with the internal proximal stop; and [0126] removing the pushing
device after disassociating the loaded catheter from the loading
device.
[0127] In a preferred embodiment the pushing device comprises a
wire for threading through the embolic protection filter, the wire
defining a distal stop for engaging the embolic protection
filter.
[0128] The loading device preferably comprises an elongate neck at
the outlet end, and the method preferably comprises the step of at
least partially aligning the elongate neck with the reception space
before delivering the embolic protection filter through the loading
device.
[0129] The method may comprise the step of flushing the embolic
protection filter before delivering the embolic protection filter
through the loading device.
[0130] The method may comprise the step of flushing the catheter
before delivering the embolic protection filter into the reception
space.
[0131] In a preferred embodiment the catheter comprises an outer
catheter tube and an inner catheter tube, the inner catheter tube
defining the internal proximal stop.
[0132] Desirably both the inner catheter tube and the outer
catheter tube are flushed before delivering the embolic protection
filter through the loading device.
[0133] According to a further aspect of the invention there is
provided a removable device for loading a collapsible embolic
protection filter into a catheter, the device comprising a distal
stop for releasably engaging with the embolic protection filter to
push the embolic protection filter towards a proximal end of a
catheter thereby loading the embolic protection filter into the
catheter.
[0134] The distal stop is preferably provided on an elongate
stem.
[0135] Most preferably the distal stop is integral with the
stem.
[0136] In one case the distal stop comprises a step in the stem
from a small diameter portion proximal of the step to a large
diameter portion distal of the step.
[0137] The small diameter portion preferably has a diameter of
approximately 0.014'' (0.3556 mm).
[0138] The large diameter portion preferably has a diameter of
approximately 0.018'' (0.4572 mm).
[0139] The distal stop may be attached to the stem.
[0140] Ideally the stem comprises a wire.
[0141] The stem may comprise a low friction coating for ease of
threading through the medical device. Ideally the coating is of
polytetrafluoroethylene.
[0142] In one case the device comprises a handle.
[0143] The invention provides a clinician with the freedom to
select from different guidewires prior to selection of an embolic
filter.
[0144] Prior art assemblies suffer from the disadvantage that
different guidewires cannot be used with a particular filter during
an interventional procedure. A clinician is thus constrained to
discard both the guidewire and the filter if the guidewire proves
unsuitable, for example because it is too stiff or some other
mechanical property is undesirable.
[0145] An important advantage of the invention is that because the
filter is not attached to the guidewire in a collapsed
configuration for delivery, the guidewire which is first advanced
through the vasculature has a lower profile. Therefore the
guidewire alone can more easily navigate narrow and tortuous
regions of the vasculature.
[0146] Another important advantage of the invention is that because
the filter is not fixed to the guidewire, if the deployed filter is
mis-sized with respect to the region of the treatment site it is
free to be carried distally by blood flow to a narrow section of
the vasculature at which the filter effectively achieves apposition
with the vessel wall. This ensures that all blood flow with
entrained embolic material passes through the filter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0147] The invention will be more clearly understood from the
following description of some embodiments thereof, given by way of
example only, with reference to the accompanying drawings, in
which: --
[0148] FIG. 1 is a perspective view of an embolic protection system
pack;
[0149] FIG. 2 is a plan view of a delivery catheter of the embolic
protection system;
[0150] FIG. 3 is a side, partially cross-sectional view of the
delivery catheter of FIG. 2;
[0151] FIG. 4 is an enlarged view of part of the delivery catheter
of FIG. 3;
[0152] FIG. 4A is a perspective, partially cut-away view of the
delivery catheter;
[0153] FIG. 5 is a side, partially cross-sectional view of a handle
piece of the delivery catheter of FIG. 3;
[0154] FIG. 6 is an enlarged view of part of the handle piece of
FIG. 5;
[0155] FIG. 7 is an enlarged view of another part of the handle
piece of FIG. 5;
[0156] FIG. 8 is a perspective view of a female luer of the
delivery catheter of FIG. 3;
[0157] FIG. 9 is a plan view of an inner catheter of the embolic
protection system;
[0158] FIG. 10 is a side, partially cross-sectional view of the
inner catheter of FIG. 9;
[0159] FIG. 11 is an enlarged view of part of the inner catheter of
FIG. 10;
[0160] FIG. 12 is an enlarged view of another part of the inner
catheter of FIG. 10;
[0161] FIG. 12A is a perspective, partially cut-away view of the
inner catheter;
[0162] FIG. 13 is a plan view of the inner catheter and the
delivery catheter assembled;
[0163] FIG. 14 is a side, partially cross-sectional view of the
catheter assembly of FIG. 13;
[0164] FIG. 15 is an enlarged view of part of the catheter assembly
of FIG. 14;
[0165] FIG. 16 is an enlarged view of another part of the catheter
assembly of FIG. 14;
[0166] FIG. 17 is a side view of the catheter assembly of FIG. 14
with the inner catheter in a distal configuration of use;
[0167] FIG. 18 is a side, partially cross-sectional view of an
embolic protection device of the embolic protection system;
[0168] FIG. 19 is a plan view of the embolic protection device of
FIG. 18;
[0169] FIG. 20 is a side view of a pushing device of the embolic
protection system;
[0170] FIG. 21 is a side, cross-sectional view of a part of the
pushing device of FIG. 8;
[0171] FIG. 22 is a side, partially cross-sectional view of a
loading device of the embolic protection system;
[0172] FIG. 23 is an enlarged view of the detail of the loading
device of FIG. 22;
[0173] FIG. 23A is a cross sectional view of an alternative loading
device;
[0174] FIGS. 24 to 27 are schematic views illustrating release and
flushing of the catheter assembly of FIGS. 13 to 17;
[0175] FIGS. 28 and 29 are schematic views illustrating release of
the pushing device of FIGS. 20 and 21;
[0176] FIG. 29A is a cross sectional view on the line AA in FIG.
29;
[0177] FIGS. 30 to 32(b) are schematic views illustrating loading
of the embolic protection device of FIGS. 18 and 19 into the
catheter assembly of FIGS. 13 to 17;
[0178] FIGS. 33 and 34 are schematic views illustrating
disassociation of the loaded catheter assembly of FIG. 32(a) from
the loading device of FIGS. 22 and 23;
[0179] FIG. 35 is a side view of a guidewire of the embolic
protection system;
[0180] FIGS. 36 to 41 are schematic views illustrating delivery and
deployment of the embolic protection device of FIGS. 18 and 19 in a
vasculature;
[0181] FIGS. 42 and 43 are schematic views illustrating treatment
of the vasculature;
[0182] FIGS. 44 to 47 are schematic views illustrating retrieval of
the embolic protection device of FIGS. 18 and 19 from the
vasculature;
[0183] FIGS. 48 to 56 are side, partially cross-sectional views of
other embolic protection devices of the embolic protection
system;
[0184] FIGS. 57 and 58 are schematic views illustrating loading of
embolic protection devices into the catheter assembly of FIGS. 13
to 17;
[0185] FIGS. 59 to 61 are schematic views illustrating loading of
the embolic protection device of FIGS. 18 and 19 into the catheter
assembly of FIGS. 13 to 17 using a removable pulling device;
[0186] FIG. 62 is a side view of the loaded catheter assembly;
[0187] FIGS. 63 and 64 are schematic views illustrating loading of
embolic protection devices into the catheter assembly of FIGS. 13
to 17 using the pulling device of FIGS. 59 to 61;
[0188] FIGS. 65 to 69 are schematic views illustrating retrieval of
an embolic protection device from a vasculature;
[0189] FIG. 70 is a side view of another guidewire of the embolic
protection system;
[0190] FIGS. 71 to 74 are schematic views illustrating deployment
of an embolic protection device in a vasculature;
[0191] FIGS. 75 and 76 are schematic views illustrating deployment
of another embolic protection device in the vasculature using
tethers;
[0192] FIG. 77 is a schematic view illustrating release of a tether
of FIGS. 75 and 76;
[0193] FIGS. 78 to 81 are schematic views illustrating delivery and
deployment of an embolic protection device of a rapid exchange
embolic protection system in a vasculature;
[0194] FIG. 82 is a side, partially cross sectional view of another
embolic protection system;
[0195] FIG. 83 is a side, partially cross sectional view of a
further embolic protection device; and
[0196] FIGS. 84 and 85 are cross sectional views of a distal
portion of catheters.
DETAILED DESCRIPTION
[0197] Referring to the drawings there is illustrated a
transvascular embolic protection system according to the invention
for safely capturing and retaining embolic material released during
an interventional procedure while maintaining blood flow.
[0198] The embolic protection system comprises an embolic
protection device 1, a delivery catheter 2 for delivery of the
embolic protection device 1 to a desired location in the vascular
system and a proximal stop for deployment of the embolic protection
device 1. The device 1 is collapsible from an expanded deployed
configuration to a retracted delivery configuration. The delivery
catheter 2 has a pod 13 at the distal end to define a reception
space for the embolic protection device 1 in the collapsed delivery
configuration. The proximal stop in this case is provided by the
distal end 27 of an inner catheter 25 which extends towards the pod
13 of the delivery catheter 2 for deployment of the embolic
protection device 1 from the pod 13.
[0199] In use, the embolic protection device 1 is loaded into the
pod 13 of the delivery catheter 2 which is delivered over a
pre-positioned guidewire 99. At a desired location the inner
catheter 25 is moved relative to the delivery catheter 2 to deploy
the embolic protection device 1 from the pod 13. The delivery and
inner catheters 2, 25 are then withdrawn leaving a bare guidewire
99 over which various devices such as a dilation balloon and/or a
stent can be advanced to the treatment site. Embolic material
dislodged during the treatment procedure(s) is collected in the
embolic protection device 1. After treatment, the device 1 may be
retrieved into a retrieval catheter 3. The guidewire 99 may be left
in place for further catheter advancements or may be withdrawn with
or subsequent to the withdrawal of the retrieval catheter 3.
[0200] Referring in particular to FIG. 1 a pack 4 is provided to
safely store and prepare the embolic protection system for use. The
pack 4 comprises a vacuum-formed tray 5, typically of PETG. The
tray 5 has a channel 6 extending in a looped configuration around
the tray 5 for receiving the delivery catheter 2. The delivery
catheter 2 has a proximal end 11 and a distal end 12. A handle 14
is provided at the proximal end 11, and the inner catheter 25 which
extends through the delivery catheter 2 has a luer 36 at the
proximal end. The luer 36 is located in the tray 5 adjacent to the
handle 14. The pod 13 is provided at the distal end 12 of the inner
catheter 2. A loading device 7 in the form of a funnel piece is
mounted in the tray adjacent to and, in this case extending into
the pod 13. The embolic protection device 1 is mounted in its
expanded configuration in a well 90 in the tray 5 adjacent to and
extending into the loading device 7. A pushing device 8 for loading
the collapsible embolic protection device 1 is mounted in the tray
5 adjacent to the embolic protection device 1. A syringe 91 is also
mounted in a recess 92 of the tray 5. The syringe 91 is used to
flush the system and, after flushing, the pushing device 8 is used
to push the embolic protection device 1 through the loading device
7 and into the pod 13 of the delivery catheter 2 in the collapsed
configuration. The delivery catheter 2 is now ready for advancement
over the guidewire 99.
[0201] Referring now to FIGS. 2 to 8, the delivery catheter 2 is
illustrated in more detail. The delivery catheter 2 comprises a
tubular body 10, typically of polyimide, or nylon extending between
a proximal end 11 and a distal end 12. At the distal end 12 of the
tubular body 10 a pod 13 is provided, the pod 13 having a smaller
wall thickness and in this case a larger internal diameter, as
illustrated in FIG. 4, to define a reception space for receiving
the embolic protection device in a collapsed configuration. The
handl 14, illustrated in detail in FIGS. 5 to 7, is attached to the
proximal end 11 of the tubular body 10, with a strain relief member
15 extending from the handle 14 partially along the tubular body
10. The handle 14 defines a central lumen 16 extending between a
proximal opening 17 and a distal opening 18. A side port opening 19
is provided in the handle 14, the side port 19 being in
communication with the central lumen 16 (FIG. 3). A female luer 20,
as illustrated in FIG. 8, is also provided, the luer 20 being
fixedly mounted in the side port 19. A double-start thread is
provided at the free end of the luer 20 for threadable attachment
of, for example, a flushing syringe 91 to the luer 20.
[0202] In this case the proximal stop is provided by an inner
catheter 25. As illustrated in FIGS. 9 to 12, the inner catheter 25
comprises a tubular body extending between a proximal end 26 and a
distal end 27. The tubular body comprises an inner tubular stem 28
extending between the proximal end 26 and the distal end 27, and an
outer tubular stem 29, typically of polyimide, extending from the
proximal end 26 only partially along the inner stem 28, as
illustrated in FIG. 10. The outer stem 29 terminates in a
protruding O-ring shoulder 30. An annular collar 31 is slidably
mounted to the outer stem 29 proximally of the O-ring shoulder 30
(FIG. 12). The female winged luer piece 36 is attached to the
proximal end 26 of the stems 28, 29 by means of a flair connector
32. The winged luer 36 defines a central lumen 33 extending between
a proximal opening 34 and a distal opening 35.
[0203] As illustrated in FIGS. 13 to 17, the inner catheter 25 is
configured for insertion through the proximal opening 17 of the
handle 14 and advancement through the handle 14 and the tubular
body 10 until the collar 31 engages the handle 14 (FIG. 15) in the
region of the proximal opening 17. The collar 31 is fixedly
attached within the proximal opening 17 of the handle 14.
[0204] The inner catheter 25 is slidable relative to the delivery
catheter 2 between a retracted position, as illustrated in FIG. 14,
in which the distal end 27 of the inner catheter 25 is proximal of
the pod 13 defining the reception space in the delivery catheter 2
(FIG. 16), and an extended position, in which the distal end 27 of
the inner catheter 25 extends distally of the pod 13 of the
delivery catheter 2 (FIG. 17). Movement of the inner catheter 25
proximally relative to the delivery catheter 2 is limited by
engagement of the O-ring shoulder 30 with the collar 31 (FIGS. 14
and 15).
[0205] The pod 13 of the delivery catheter 2 and the inner stem 28
of the inner catheter 25 at least partially comprise a stiff core,
for example of a metallic material, such as stainless steel,
encased in a more pliable body, for example of a plastics material
such as polyimide. The cores comprise a mesh of longitudinally
oriented strips of the stiff material and circumferentially
oriented strips of the stiff material.
[0206] Accurate delivery of a filter to its intended location (a
non-diseased vessel area) is a particularly important concern in
tortuous anatomy where there is a limited area of non-diseased
vessel. The accuracy of deployment is related to the build up of
potential stain energy in delivery catheter systems. This strain
energy is primarily a combination of strain energy produced in the
outer and inner shaft during the deployment action. The designs
described below referring in particular to FIGS. 4A and 12A detail
a novel solution to these problems.
[0207] During the deployment action the outer shaft or delivery
catheter 2 is subjected to high levels of tensile strain. The
design/construction of the outer shaft 2 is such that the amount of
strain energy that can be stored within the outer shaft is
minimised. Low flexural stiffness is also desirable in catheter
design to ensure good catheter flexibility, trackability and low
insertion forces. These attributes are achieved by incorporating
high tensile elements 21 within the wall construction of the outer
shaft 2. These high tensile elements 2 can be high tensile
longitudinal steel wires as shown in the example below or they may
be flexible high tensile wires or fibers, carbon fibers and or
kevlar fibers. These fibers/wires are contained within the wall 22
of the catheter which may be a polymeric material (detailed in FIG.
4A is a polyimide wall). These wires/fibers provide the outer shaft
with high tensile modulus (minimal stretch) which results in a
shaft that can not store much strain energy. The inclusion of the
above high tensile elements 21 allows for a low profile outer shaft
2. This low wall thickness outer catheter shaft therefore also has
low flexural stiffness, good flexibility, trackability and
subsequently low insertion force. The inner surface 23 of the lumen
of this shaft 2 is a low friction (PTFE) material to minimise the
friction strain energy incurred during the deployment action.
[0208] During the deployment action the inner catheter shaft 25 is
subjected to high levels of compression strain. The
design/construction of the inner shaft 25 is such that the modulus
of compression is high which reduces the amount of strain energy
that can be stored within the inner shaft 25. This is achieved by
incorporating elements 24 with high compression modulus. These
elements are contained within a material matrix 24A that further
enhances the compression modulus of the inner shaft 25. The
inclusion of the above high compression elements allows for a low
profile outer shaft. The low wall thickness inner shaft will
therefore also have low flexural stiffness, good flexibility and
trackability. The example illustrated in FIG. 14A is a high
compression modulus steel wire braid 24 contained within a
polymeric matrix 24A. The inner lumen of the shaft 25 is made of a
low friction (PTFE) material layer 24B. The outer surface of the
shaft 25 is also provided with a low friction (FEP) material layer
24C. The layers 24 B and 24C minimise the frictional strain energy
incurred during delivery and deployment. Due to the combination of
the above inner and outer shaft 2,25 the amount of strain energy
that can be stored within the system during use is very low. Due to
the low strain energy build up within the system a precise,
controlled, low force deployment is achieved even in difficult
vessel paths.
[0209] In this case, the embolic protection device 1 comprises a
collapsible filter element 40 for delivery through a vascular
system of a patient and deployment at a desired location in the
vascular system. FIGS. 18 and 19 illustrate the filter element 40
in detail.
[0210] The filter element 40 comprises a collapsible filter body
41, a collapsible filter support frame 42 contacting the filter
body 41, and an inner elongate sleeve 43 to which both the filter
body 41 and the frame 42 are mounted. A proximal end 44 of the
filter body 41 and a proximal end 45 of the frame 42 are both
fixedly attached to a proximal end 46 of the sleeve 43, in this
case by means of an adhesive bond. A distal end 47 of the filter
body 41 and a distal end 48 of the frame 42 are free to slide over
a distal end 49 of the sleeve 43.
[0211] The filter body 41 has a proximal inlet end and a distal
outlet end. The inlet end of the filter body 41 has one or more, in
this case two, large inlet openings 50, and the outlet end has a
plurality of, in this case approximately three hundred, small
outlet openings 51 sized to allow through passage of blood but to
retain undesired embolic material within the filter body 41.
[0212] The filter support frame 42 is movable between a collapsed
position for movement of the filter element 40 through a vascular
system and an extended outwardly projecting position to support the
filter body 41 in an expanded position. The frame 42 has a distal
section 52, an intermediate section 53 for urging the filter body
41 in the expanded position into apposition with a vascular vessel
wall, and a proximal section 54 extending proximally and radially
inwardly of the intermediate section 53 (FIGS. 18 and 19).
[0213] At least part of the proximal section 54 of the frame is
spaced distally of the inlet openings 50 in the filter body 41 to
accommodate inflow of embolic material through the inlets 50 and
into the expanded filter body 41. The filter body 41 comprises one
or more, in this case two, linking webs 55 between adjacent inlets
50, and a part of the proximal section 54 of the frame extends
radially inwardly in alignment with the webs 55, as illustrated in
FIG. 19, to avoid occluding the inlets 50 to the filter body 41
when the filter body 41 is in the expanded position. In this manner
the possibility of embolic material becoming caught or hung-up on
the proximal section 54 of the frame as the embolic material flows
distally through the inlet openings 50 is minimised.
[0214] The proximal section 54 of the frame comprises one or more
frame elements, in this case four. At least one frame element, in
this case two, provides the part of the proximal section 54 which
is spaced distally of the inlets 50, and at least one frame
element, in this case two, provides the part of the proximal
section 54 extending radially inwardly in alignment with the webs
55.
[0215] The proximal section of the frame runs generally parallel
with a vessel wall and then turns radially inwards. The proximal
arm(s) of the frame have a section that is displaced distally. The
advantage of this displacement is that it creates an inlet path
which is offset and therefore larger.
[0216] The frame elements are preferably of a shape memory
material, such as Nitinol, or of a superelastic material, and may
have a plating of gold or other dense material around the Nitinol.
The frame elements facilitate movement of the frame 42 between the
collapsed position and the extended outwardly projecting position.
The frame 42 is electropolished.
[0217] The sleeve 43 defines a lumen 56 extending therethrough for
exchange of the filter element 40 over the guidewire 99. The distal
end 49 of the sleeve 43 is engageable with a stop such as a stop on
the guidewire 99. This is particularly useful for retrieval of the
filter element 40 from a vascular system. The sleeve 43 is
typically of polyimide.
[0218] The sleeve 43 acts as a barrier between the lumen 56 through
which a guidewire may be exchanged, and the internal annular volume
of the filter body 41 within which embolic material is retained. In
particular, the proximal end 46 of the sleeve 43 is proximal of the
inlets 50, and the distal end 49 of the sleeve 43 is distal of the
small outlets 51. This ensures that all blood flows into the filter
body 41 through the inlets 50, through the filter body 41 and out
of the filter body 41 through the small outlets 51 which are sized
to retain undesired embolic material within the filter body 41. The
sleeve 43 prevents escape of any embolic material from the filter
body 41 into the lumen 56, for example, during exchange of medical
devices over a guidewire received within the lumen 56, or during
retrieval of the filter element 40.
[0219] A guide olive 57 is provided for atraumatic delivery of the
filter element 40 through a vascular system, the guide olive 57
forms an extension of the distal end 47 of the filter body 41 and
tapering distally inwardly for a smooth transition profile. In this
case, the guide olive 57 is integral with the filter body 41 and is
of the material Pellethane. As illustrated in FIGS. 18 and 19, the
guide olive 57 extends distally of the distal end 49 of the sleeve
43.
[0220] In use, the region of a vasculature in which the filter
element 40 is deployed is substantially straight for a length at
least equal to the longitudinal length of the filter element 40 to
ensure apposition of the filter body 41 with the vasculature wall.
By directly mounting the guide olive 57 at the distal end 47 of the
filter body 41, the overall longitudinal length of the filter
element 40 is reduced to define a longitudinally compact filter
element 40. Thus, the user has greater freedom when choosing a site
in a vasculature to deploy the filter element 40 because the length
of the vasculature which is required to be straight is
correspondingly reduced.
[0221] As illustrated in FIGS. 18 and 19, the distal end 48 of the
frame 42 acts to reinforce the proximal section of the guide olive
57 and prevents flaring of the sleeve 43. The guide olive 57 has a
soft distal tip 58.
[0222] Two gold marker bands 59, 60 are provided mounted to the
sleeve 43. One marker band 59 is fixedly attached to the olive 51
and one marker band 60 is fixedly attached to the proximal end 45
of the frame 42. The marker bands 59, 60 assist in visualisation of
the filter element 40 during an interventional procedure.
[0223] A transition element 61 is fixedly mounted to the proximal
end 46 of the sleeve 43, in this case by means of an adhesive bond.
The transition element 61 is sized to fit made the lumen of the
delivery catheter 2 to provide a smooth stiffness transition and
prevent kinking.
[0224] Referring now to FIGS. 20 and 21, the pushing device 8 for
loading the collapsible filter element 40 into the pod 13 of the
delivery catheter 2 is illustrated. The pushing device 8 comprises
a handle 70 for gripping the pushing device 8 and an elongate stem
in this case provided by a wire 71, extending from the handle 70
for threading through the lumen 56 of the filter element 40. The
wire 71 defines a distal stop 72 for releasably engaging with the
distal end 49 of the sleeve 43 of the filter element 40 to push the
filter element 40 into the pod 13 of the delivery catheter 2.
[0225] As illustrated in FIG. 21 the distal stop 72 is provided by
an end 74 of an outer hypotube 73 which extends from the handle 70
partially along the wire 71. The free end 74 of the hypotube 73
forms a step from the small diameter wire 71 proximal of the step
to the larger diameter hypotube 73 distal of the step. The small
diameter is preferably approximately 0.014'' (0.3556 mm), and the
large diameter is preferably approximately 0.018'' (0.4572 mm). The
hypotube 73 may be attached to the wire 71 by any suitable means,
such as an adhesive means, or a mechanical keying means, or by
brazing, or soldering, or welding, or by any other suitable
means.
[0226] The wire 71 may have a low friction coating, for example of
polytetrafluoroethylene, for ease of threading of the wire 71
through the filter element 40. The handle 70 facilitates ease of
gripping and of use of the pushing device 8.
[0227] It will be appreciated that the distal stop 72 may be
provided integral with the wire 71, for example by machining a step
in the wire 71.
[0228] It will further be appreciated that the large diameter
portion distal of the step may be only a locally defined feature on
the wire 71 that does not extend distally to the handle 70.
[0229] The loading device 7 is illustrated in detail in FIGS. 22
and 23. The loading device 7 defines a funnel having an inlet end
80 and an outlet end 81, the inlet end 80 defining a larger
cross-sectional area than the outlet end 81, and the outlet end 81
being configured for co-operative alignment with the reception
space of the delivery catheter 2.
[0230] The loading device 7 has means for radially compressing the
filter element 40 from the extended outwardly projecting position
to the collapsed position. In this case, the loading device 7
comprises a main support 82 having a funnel-shaped bore formed from
a frusto-conical filter element receiving portion terminating in a
cylindrical portion formed by a thin walled loading tube 83
projecting from the main support 82 for positioning within the
reception space of the delivery catheter 2.
[0231] The cone angle of the bore is chosen from an angle in the
range of between 15.degree. and 65.degree., preferably between
35.degree. and 45.degree..
[0232] The loading tube 83 is preferably formed from
polyethyleneterephthalate (PET), and is mounted on a metal spigot
84, typically a grit blasted hypotube, by a combination of a
polyolefin shrink tube bond and an adhesive bond. The metal spigot
84 is adhesively fixed to the main support 82 which is formed from
"Perspex" or a similar material. The loading tube 83 may be coated
with a lubricant.
[0233] Referring to FIG. 23A there is illustrated an alternative
loading device 85 in which an outer support 86 is provided around
the pod 13 of the delivery catheter 2. A smooth transition is
provided by a funnel section 87 and the distal end of the pod 13.
The area between the outer support 86 and the pod 13 may be a
wetted annular space for ease of mounting and demounting.
[0234] Referring to FIGS. 1 and 24 to 29, the tray 5 will now be
described in more detail. The tray includes integral projections 9
that extend into various recesses. The projections 9 releasably
support the loading device 7 in co-operative alignment with the
delivery catheter 2 before loading and during the loading
procedure. In particular, the loading device 7 is supported with
the loading tube 83 extending proximally into the reception space
of the delivery catheter 2 before loading and during the loading
procedure. In addition, the projections 9 on the channel wall are
configured to releasably support the pushing device 8 in a position
in which the distal stop 72 does not engage the filter element 40
before the loading procedure commences.
[0235] The projections 9 are also configured to releasably support
the luer 20 of the delivery catheter 2 in the horizontal position
illustrated in FIGS. 1 and 24. In this position it is not possible
to slide the delivery catheter 2 proximally in the channel 6, or,
in the configuration illustrated, to flush the delivery catheter 2
through the luer 20.
[0236] A liquid retaining bath 90 is provided by recesses in the
tray 5, the bath 90 having a depth sufficient to accommodate in a
totally submerged state the reception space of the delivery
catheter 2 and the filter element 40 for submerged loading of the
filter element 40 through the loading device 7 and into the pod 13
of the delivery catheter 2. As illustrated in FIG. 1, the channel 6
communicates with the bath 90, and a ramp is provided at an end of
the channel 6 communicating with the bath 90 to direct the
reception space downwards towards the bottom of the bath 90 but
supporting the pod 13 of the delivery catheter 2 above the bottom
of the bath 90 by means of a step.
[0237] The syringe 91 is provided for flushing the delivery
catheter 2, the inner catheter 25, the loading device 7 and the
filter element 40. The recess 92 is provided in the tray 5 for snap
retention of the syringe 91 before use.
[0238] The components of the embolic protection system are placed
in the pack 4 in the following manner. The loading device 7 is
snapped into place in the channel 6, with the projections 9
releasably supporting the loading device 7 in the position
illustrated in FIG. 1.
[0239] The inner catheter 25 is inserted through the proximal
opening 17 of the handle 14, and advanced through the handle 14 and
the tubular body 10 until the collar 31 engages the proximal
opening 17 of the handle 14. The collar 31 is fixedly attached
within the proximal opening 17 of the handle 14 by pushing the
collar 31 home to create an interference fit between the collar 31
and the proximal opening walls. This catheter assembly is then
looped through the channel 6 and held in place so that the loading
tube 83 of the loading device 7 extends proximally into the pod 13
of the delivery catheter 2.
[0240] The wire 71 of the pushing device 8 is then threaded through
the filter element 40, a proximal end of the wire 71 is inserted
through the loading device 7 and extended partially through the
inner catheter 25. The handle 70 is snapped into place in the
channel 6 by the projections 9. In this configuration the filter
element 40 is slidable over the wire 71 but is normally positioned
within the bath 90, as illustrated in FIG. 1. The projections 9
retain the pushing device 8 in a position in which the distal stop
72 is spaced distally of the bath 90, and so the distal stop 72
does not engage the filter element 40 in this storage
configuration, as illustrated in FIG. 1.
[0241] The syringe 91 is snapped into place in the recess 92, and
the assembled pack 4 is now ready to be sealed and stored until
required for use.
[0242] In this storage configuration the filter element 40 is in
the expanded configuration. This is an advantageous arrangement. If
the filter element 40 was loaded into the delivery catheter 2 and
stored in the collapsed position for a long period of time, the
filter element 40 would be subject to material deformation, in
particular to material creep. The assembled pack 4 of the invention
may be safely stored for long periods in a packaged configuration
without risk of filter element material deformation. The pack 4 is
placed in a porch and sealed.
[0243] When the assembled pack 4 is required for use, the seal is
broken, the pack 4 is removed and the syringe 91 is removed from
the recess 92. The luer 20 of the delivery catheter 2 is rotated
through 90.degree. in a "bolt-action" to release the luer 20 from
the snap-fit retaining projections 9 in the tray 5, as illustrated
in FIGS. 24 and 25. The delivery catheter 2 is now slidable
proximally in the channel 6, and the luer 20 is now accessible for
flushing (FIG. 25). The syringe 91 is used to flush the delivery
catheter 2 through the luer 20 (FIG. 26) and to flush the inner
catheter 25 through the proximal opening 34 in the female luer
piece 36 of the inner catheter 25 (FIG. 27). A saline solution is
generally used for flushing the catheters 2, 25. The syringe 91 is
also used to fill the bath 90 with saline solution, thereby
immersing the filter element 40, the reception space of the
delivery catheter 2 and the loading device 7 in the saline
solution. This ensures all removed from the system.
[0244] This flushing step is performed shortly before intended use.
The filter element 40 is completely visible and accessible to the
user during prepping. In this way, the user can squeeze or pinch
parts of the filter element 40 to ensure the filter element 40 is
completely flushed of air. This is difficult if the filter element
40 was loaded into the delivery catheter 2 upon assembly and stored
for a potentially long period in the collapsed position.
[0245] The flushed filter element 40 is now ready for loading into
the pod 13 of the delivery catheter 2. The pushing device 8 is
rotated through 90.degree. in a "bolt-action" to release the handle
70 from the snap-fit retaining projections 9 in the tray 5, as
illustrated in FIGS. 28 and 29. In this configuration the pushing
device is still retained to the tray (FIG. 29A). The pushing device
8 is now free to slide proximally in the channel 6 (FIG. 30), until
the distal stop 72 engages with the distal end 49 of the sleeve 43
of the filter element 40 (FIGS. 31(a) and 31(b)). Continued pushing
of the pushing device 8 will push the filter element 40 proximally
towards the loading device 7 (FIG. 31(a)), through the loading
device 7, thereby collapsing the filter element 40 from the
extended outwardly projecting position of FIG. 31(a) to the
collapsed position of FIG. 32(a), and into the pod 13 of the
delivery catheter 2 (FIG. 32(a)) until the filter element 40 abuts
the distal end 27 of the inner stem 28 of the inner catheter 25.
Further pushing of the pushing device 8 moves the collapsed filter
element 40 and the inner catheter 25 proximally until the O-ring
shoulder 30 of the inner catheter 25 abuts the annular collar 31
fixed in the proximal opening 17 of the handle 14, as illustrated
in FIGS. 14 and 15. An O-ring 39 is also provided between the
shoulder 30 and the collar 31.
[0246] The loading device 7 has thus far remained in co-operative
alignment with the delivery catheter 2. Because the luer 20 of the
delivery catheter 2 has been released from the snap-fit retaining
projections 9 in the tray 5, as illustrated in FIG. 32(b), the
catheter assembly is free to slide proximally in the channel 6 away
from the loading device 7. When the pushing device 8 is further
pushed proximally, this causes the inner catheter 25 to move
proximally and with it the delivery catheter 2 due to the
engagement of the O-ring shoulder 30 with the handle 14. In this
manner, the delivery catheter 2, the inner catheter 25 and the
collapsed filter element 40 are all moved together proximally away
from the loading device 7, and thereby the loaded catheter assembly
is disassociated from the loading device 7 (FIG. 33).
[0247] The loaded catheter assembly is then removed from the
channel 6 leaving the loading device 7 and the pushing device 8
behind in the channel 6. The assembly of the loaded delivery
catheter 2 and the inner catheter 25, as illustrated in FIG. 34, is
now ready for insertion into a vascular system of a patient.
[0248] The filter element 40 is loaded into the pod 13 of the
delivery catheter 2 by a simple, single-direction pushing action.
This minimises potential loading difficulties.
[0249] The components of the pack 4 are retained in the correct
loading alignments by the tray 5. The pushing device 8 is
completely separated from the loaded catheter assembly after
completion of the loading procedure.
[0250] In addition, the loaded filter element 40 is not attached or
associated in any way with the pushing device 8. Thus, the user is
free to choose any suitable guidewire, as desired, for subsequent
delivery of the filter element 40 through a vascular system of a
patient.
[0251] Referring now to FIG. 35 the guidewire 99 of the embolic
protection system is illustrated in detail. The guidewire 99 is
suitable for the exchange of the filter element 40 through a
vascular system of a patient over the guidewire 99. The guidewire
99 defines a distal end 100 and comprises a distal stop 101 to
prevent relative movement of the filter element 40 distally of the
distal end 100 of the guidewire 99. The portion of the guidewire 99
proximally of the distal stop 101 is bare for exchange of the
filter element 40 and/or other medical devices over the guidewire
99.
[0252] In this case the distal stop 101 is provided by a wire coil
102 fixedly attached around the distal end 100 of the guidewire 99
(FIG. 35). The coil 102 has a larger outer diameter than the bare
portion of the guidewire 99 to define a step from the small
diameter bare portion of the guidewire 99 to the large diameter
coil portion of the guidewire 99. The small diameter is preferably
approximately 0.014'' (0.3556 mm), and the large diameter is
preferably 0.018'' (0.4572 mm). A curve is typically formed towards
the distal end 100 of the guidewire 99 to facilitate navigating
and/or positioning the guidewire 99 in a vasculature.
[0253] The coil 102 may be attached to the small diameter portion
of the guidewire 99 by an adhesive means, or by a mechanical keying
means, or by brazing, or soldering, or welding, or by any other
suitable means of attachment.
[0254] In this case, the guidewire 99 is partially of stainless
steel, and partially of a radiopoque material to aid the user in
positioning the guidewire 99 accurately in a vasculature. The
guidewire 99 has a coating of a low friction material, for example
of a fluoropolymer such as polytetrafluoroethylene, or of a
silicone material, or of a hydrophilic material, for ease of
advancement of the guidewire 99 through a vasculature and ease of
exchange of the filter element 40 and/or other medical devices over
the guidewire 99.
[0255] As illustrated in FIG. 35, the large diameter coil 102
extends distally of the step to the distal end 100 of the guidewire
99. However it will be appreciated that the large diameter portion
of the guidewire 99 may extend distally of the step only a part of
the distance to the distal end 101 of the guidewire 99. The large
diameter portion may taper distally inwardly back to the small
diameter in an arrow-head type shape or by gradually tapering.
[0256] Referring now to FIGS. 36 to 41, delivery and deployment of
the filter element 40 at a desired location within a vasculature
110 is illustrated. The guidewire 99 will be selected to suit the
geometry of the vasculature 110 to be negotiated, and/or the
disease site, and/or the preference of the user. The guidewire 99
is firstly inserted on its own into the vasculature system of a
patient and advanced through the vasculature 110 until the distal
stop 101 of the guidewire 99 is distal of a treatment site such as
a region of stenosis 111 in the vasculature 110 (FIG. 36).
[0257] The curved distal end 100 of the guidewire 99 is often
anchored in a bend in the vasculature 110 distally of the stenosed
region 111 (FIG. 41) to facilitate some straightening of the
anatomy by the user prior to delivery of the filter element 40.
[0258] The loaded delivery catheter assembly of FIG. 34 is then
inserted into the vasculature system and advanced over the
guidewire 99 through the vasculature 110, until the pod 13 of the
delivery catheter 2 with the collapsed filter element 40 therein is
positioned at a desired location of the vasculature 110 distally of
the stenosed region 111 (FIG. 37). At least part of the filter
element 40, in this case part of the distal end 58 of the guide
olive 57, protrudes distally out of the pod 13 of the delivery
catheter 2 during advancement of the delivery catheter 2 through
the vascular system to minimise trauma to the vessel walls. The
olive also provides a stiffness transition.
[0259] The delivery catheter 2 is retracted while maintaining the
position of the inner catheter 25 (FIG. 38). In this way the distal
end 27 of the inner stem 28 of the inner catheter 25 acts as a
proximal stop against which the transition element 61 of the filter
element 40 abuts, thus the distal end 27 of the inner stem 28 of
the inner catheter 25 prevents retraction of the collapsed filter
element 40 with the delivery catheter 2. As the restraining
delivery catheter 2 is withdrawn, the filter element 40 is freed to
expand from the collapsed, delivery configuration to the extended,
outwardly projecting position of FIG. 39.
[0260] The filter element 40 may alternatively be deployed by
advancing the inner catheter 25 while maintaining the position of
the delivery catheter 2. In this case the distal end 27 of the
inner stem 28 of the inner catheter 25 effectively acts as a pusher
to eject the collapsed filter element 40 from the pod 13 of the
delivery catheter 2, and thereby facilitate expansion of the filter
element 40 to the deployed configuration of FIG. 39.
[0261] It will be appreciated that the filter element 40 may be
deployed by any sufficient movement of the delivery catheter 2
proximally relative to the inner catheter 25, thereby engaging the
distal end 27 of the inner stem 28 of the inner catheter 25 with
the filter element 40 to facilitate deployment of the filter
element 40.
[0262] The construction of the pod 13 of the delivery catheter 2
and the inner stem 28 of the inner catheter 25 prevent deformation
of the pod 13 and the inner stem 28 during deployment of the filter
element 40. In particular, elongation of the pod 13 and compression
of the inner stem 28 are avoided. This ensures that the filter
element 40 is accurately and smoothly deployed in the desired
location in the vasculature 110.
[0263] In the extended outwardly projecting position the filter
body 41 is in complete circumferential apposition with the wall of
the vasculature 110 over a length substantially equal to the
intermediate section 53 of the filter support frame 42.
[0264] After deployment of the filter element 40 both the delivery
catheter 2 and the inner catheter 25 are retracted and withdrawn
from the vasculature 110, leaving the guidewire 1 in place in the
vasculature 110, and the deployed filter element 40 in place in the
vasculature 110 distally of the stenosed region 111 (FIGS. 40 and
41).
[0265] The guidewire 99 is not attached to the filter element 40,
and thus the guidewire 99 is free to rotate and/or to move
longitudinally relative to the deployed filter element 40. This is
highly advantageous as it prevents any accidental movement of the
guidewire 99 causing twisting and/or dislodging of the deployed
filter element 40. Thus, the user has more freedom to carry out a
treatment procedure on the stenosed region 111 without the risk of
intimal abrasion, or of the deployed filter element 40 becoming
dislodged or in some other way creating a potential flow path for
embolic material around the filter element 40.
[0266] In addition, the portion of the guidewire 99 in place in the
vasculature 110 proximal of the deployed filter element 40 is bare.
This bare portion of the guidewire 99 facilitates the exchange of a
wide variety of different medical devices, for example a treatment
means, over the bare guidewire 99 while the deployed filter element
40 remains in place in the vasculature 110. Examples of such
medical devices are atherectomy devices to carry out an atherectomy
procedure on the stenosed region 111, or an angioplasty balloon 112
to carry out an angioplasty procedure on the stenosed region 111,
as illustrated in FIG. 42, or a stent 113 to carry out a stenting
procedure on the stenosed region 111, as illustrated in FIG. 43, or
any possible combination of these procedures, or any other
therapeutic or diagnostic procedure. Any embolic material released
during such an interventional procedure will be collected and
safely retained in the filter element 40.
[0267] After completion of an interventional procedure, for example
a treatment of the stenosed region 111, the retrieval catheter 3 is
flushed, for example with a saline solution, using the syringe 91.
In this case, the retrieval catheter 3 comprises an elongate
tubular centring catheter 121. The centring catheter 121 has a
tapered distal tip 122 which protrudes distally of a distal end 120
of the retrieval catheter 3 during advancement through the
vasculature 110, as illustrated in FIG. 44, to prevent snagging of
the retrieval catheter 3 on the stent 113, and to minimise vessel
trauma.
[0268] The retrieval catheter 3 is inserted into the vascular
system and advanced over the bare guidewire 99 until the distal end
120 of the retrieval catheter 3 is distal of the stent 113 (FIG.
44). The retrieval catheter 3 is then further advanced distally
over the guidewire 99 while maintaining the position of the
centring catheter 121 until the distal end 120 of the retrieval
catheter 3 is immediately proximal of the deployed filter element
40. The guidewire 99 is retracted to engage the distal stop 101
with the distal end 49 of the sleeve 43 of the filter element
40.
[0269] The distal stop 101 of the guidewire 99 may alternatively be
engaged with the distal end 49 of the sleeve 43 of the filter
element 40 by advancing the retrieval catheter 3 further distally
to engage the deployed filter element 40 and push the deployed
filter element 40 distally until the distal end 49 of the sleeve 43
of the filter element 40 engages the distal stop 101 of the
guidewire 99. In this case no retraction of the guidewire 99 is
necessary to engage the distal stop 101 with the distal end 49 of
the sleeve 43 of the filter element 40.
[0270] It will be appreciated that any suitable combination of
advancement of the retrieval catheter 3 and retraction of the
guidewire 99 may be employed to effect engagement of the distal
stop 101 of the guidewire 99 with the distal end 49 of the sleeve
43 of the filter element 40.
[0271] With the distal stop 101 of the guidewire 99 engaging the
distal end 49 of the sleeve 43 of the filter element 40, the
retrieval catheter 3 is advanced while maintaining the position of
the guidewire 99 (FIG. 45). This causes the filter element 40 to
collapse into the retrieval catheter 3 until the filter element 40
is retrieved into the retrieval catheter 3 (FIG. 46).
[0272] The filter element 40 may alternatively be retrieved into
the retrieval catheter 3 by retracting the guidewire 99 while
maintaining the position of the retrieval catheter 3 to collapse
and retrieve the filter element 40 into the retrieval catheter 3.
In this case the guidewire 99 acts to pull the filter element 40
proximally into the retrieval catheter 3.
[0273] It will be appreciated that the filter element 40 may be
retrieved by any suitable movement of the retrieval catheter 3
distally relative to the guidewire 99.
[0274] The distal stop 101 facilitates retrieval of the filter
element 40 by preventing the filter element 40 moving distally of
the distal end 100 of the guidewire 99.
[0275] The guide olive 57 of the filter element 40 may or may not
protrude distally out of the distal end 120 of the retrieval
catheter 3 after collapse of the filter element 40.
[0276] The retrieval filter element 40 is then withdrawn from the
vasculature 110 by withdrawing the retrieval catheter 3 and the
centring catheter 121 together from the vasculature 110.
[0277] The guidewire 99 may be left in place in the vasculature 110
after the retrieval catheter 3, the centring catheter 121, and the
retrieval filter element 40 have been withdrawn from the
vasculature 110, as illustrated in FIG. 47. Alternatively the
guidewire 1 may be withdrawn from the vasculature 110 upon
withdrawal of the retrieval catheter 3, the centring catheter 121,
and the retrieval filter element 40.
[0278] When the bare guidewire 99 is left in place in the
vasculature 110 after withdrawal of the retrieval catheter 3, a
further treatment or diagnostic means may be advanced over the bare
guidewire 99 to access any desired location in the vasculature 110.
The position of the bare guidewire 99 may be adjusted proximally or
distally, as desired, to suit a further treatment or diagnostic
procedure. Otherwise a fluroscopic assessment of the treated vessel
may be made through the guiding catheter or sheath prior to
withdrawal of the guidewire. This is desirable.
[0279] The embolic protection system of the invention offers
considerable clinical advantages. The arrangement allows a
clinician to select a suitable guidewire from a range of such
guidewires. This provides enhanced flexibility by ensuring that
filter performance can be optimised. The embolic protection device
is not dedicated to a particular guidewire.
[0280] Because the embolic protection device is not attached to the
guidewire, the guidewire which is first advanced through a
vasculature can have a low profile and be tailored to the proposed
procedure or vasculature. Consequently, the guidewire can easily
navigate narrow and tortuous regions of the vasculature.
[0281] Thus, a clinician may readily select a particular type of
guidewire which provides the appropriate flexibility and
performance required for a particular vascular procedure being
performed. The system also facilitates the safe crossing of a
lesion not only in a first lesion.
[0282] Another important advantage is that because the embolic
protection device is not attached to the guidewire, if the embolic
protection device is under-sized with respect to the region of the
treatment site it is free to be carried by blood flow to a distal
narrowed section of the vasculature at which the embolic protection
device effectively achieves apposition with the vessel wall. This
ensures that all blood flow with entrained embolic material passes
through the embolic protection device. The guidewire distal stop
prevents movement of the embolic protection device distally off the
guidewire.
[0283] The possibility of successfully achieving filter deployment
at the intended site is significantly improved due to: [0284]
Initial crossing with a bare guidewire is easier as a bare
guidewire has an extremely low profile, is highly trackable and
highly pushable. [0285] Attempted crossing with a bare guidewire
presents a very low risk of an embolic event due to its low
profile, and atraumatic tip. [0286] Once the bare wire is across
the lesion, crossing with the filter delivery system is simplified.
Advancing the tip of the guidewire and positioning it in the distal
vasculature provides additional support to the filter delivery
catheter.
[0287] The possibility of successfully delivering other catheters
and interventional devices to the lesion area is enhanced because
of the independent movement compatibility of the deployed filter
and guidewire. The guidewire tip can be advanced into the distal
vasculature to provide anchorage during the advancement of
additional catheters and devices. The filter position is maintained
by visual apposition and blood flow forces. In this configuration
the wire provides extra support to the catheter or interventional
device being advanced. This increases the possibility of delivering
the catheter to the intended location and minimises the possibility
of an uncontrolled proximal movement of the guidewire/filter. This
uncontrolled proximal movement occurs when the guidewire has
insufficient support to guide an advancing catheter, through a
tortuous path. With fixed wire systems the filter may be quickly
withdrawn back into the lesion area with increased risk of an
embolic event or stent dislodgement. The design of this invention
substantially eliminates some of these serious clinical risks.
[0288] Referring now to FIGS. 48 to 56 there is illustrated other
embolic protection devices which are similar to the embolic
protection device of FIGS. 1 to 47, and similar elements are
assigned the same reference numerals in FIGS. 48 to 56.
[0289] In the case of the embolic protection devices of FIGS. 48 to
51 the lumen 56 of the sleeve 43 is of a diameter greater than the
outer diameter of the pushing device distal stop 72, and greater
than the diameter of the guidewire distal stop 101. Thus, the
distal end 49 of the sleeve 43 is not engageable with either the
distal stop 72 of the pushing device 8 or the distal stop 101 of
the guidewire 99. Instead an engagement grip 130 is provided on an
inner wall of the sleeve 43, the engagement grip 130 providing an
abutment for engagement with the distal stop 72 of the pushing
device 8, and for engagement with the distal stop 101 of the
guidewire 99.
[0290] The engagement grip 130 may be provided at the proximal end
46 of the sleeve 43 (FIGS. 48 and 50) or at the distal end 49 of
the sleeve 43, or at any suitable point along the length of the
sleeve 43 as desired (FIGS. 49 and 51).
[0291] The engagement grip 130 may be provided by a relatively
short stop rigidly attached to the inner wall of the sleeve 43, as
illustrated in FIGS. 48 and 49, for example by chemical means, such
as an adhesive, or by mechanical means, such as welding, or
brazing, or soldering, or keying means.
[0292] Alternatively the engagement grip 130 may be provided by
crimping a portion of the sleeve 43, as illustrated in FIGS. 50 and
51.
[0293] In the case of FIGS. 52 to 54, the distal end 49 of the
sleeve 43 is engageable with the distal stop 72 of the pushing
device 8, and the distal stop 101 of the guidewire 99. However, the
sleeve 43 does not extend along the length of the filter body 41 as
far distally as in the embolic protection device of FIGS. 1 to 51.
The sleeve 43 may terminate close to the distal end 47 of the
filter body 41 (FIG. 52), or close to the proximal end 44 of the
filter body 41 (FIG. 54), or at any suitable point along the filter
body 41 (FIG. 53).
[0294] In the case of FIGS. 55 and 56, a distal portion of the
lumen 56 of the sleeve 43 is of a diameter greater than the outer
diameter of the pushing device distal stop 72, and greater than the
diameter of the guidewire distal stop 101, and a proximal portion
of the lumen 56 of the sleeve 43 is of a smaller diameter to
facilitate engagement of the distal stop 72 of the pushing device 8
and engagement of the distal stop 101 of the guidewire 99 with a
step 140 in the sleeve 43. The step 140 may be provided by
overlapping a small diameter sleeve with a large diameter sleeve
(FIG. 55), or alternatively the step 140 may be provided integral
with the sleeve 43 for example by machining the step 140 into the
sleeve 43.
[0295] Referring to FIG. 57 there is illustrated the loading of an
embolic protection device, which is similar to that illustrated
above in FIG. 49, into the pod 13 at the distal end 12 of the
delivery catheter 2. The loading procedure is similar to that
described above with reference, in particular, to FIGS. 28 to 34.
In the case of FIG. 57, the distal stop 72 on the pushing device 8
engages the engagement grip 130 on the inner wall of the sleeve 43
to push the embolic protection device through the loading device 7
and into the delivery catheter reception space, thereby collapsing
the embolic protection device, as described previously.
[0296] FIG. 58 illustrates the loading of an embolic protection
device, which is similar to that illustrated above in FIG. 48, into
the pod 13 of the delivery catheter 2.
[0297] It will be appreciated that the engagement grip 130 may be
of any suitable configuration that facilitates engagement with the
distal stop 72 of the pushing device 8 for loading the embolic
protection device into the pod 13 of the delivery catheter 2.
[0298] Referring to FIGS. 59 to 62 there is illustrated an
alternative loading of the filter element 40 into the pod 13 at the
distal end 12 of the delivery catheter 2, which is similar to the
loading procedure described above with reference, in particular, to
FIGS. 28 to 36. In this case, a pulling device 150 is provided in
place of the pushing device 8. The pulling device 150 is similar to
the pushing device 8 described above, in particular with reference
to FIGS. 20 and 21. However, the wire 71 of the pulling device 150
extends proximally through the inner catheter 25, and out of the
proximal opening 34 of the catheter for manipulation by a user.
[0299] The filter element 40 is loaded by pulling the pulling
device 150 proximally to engage the distal stop 72 of the pulling
device 150 with the distal end 49 of the sleeve 43. Further pulling
of the pulling device 150 draws the filter element 40 through the
loading device 7 and into the pod 13 at the distal end 12 of the
delivery catheter 2, thereby collapsing the filter element 40, in a
manner similar to that described previously. Further pulling of the
pulling device 150 proximally disassociates the loaded catheter
assembly from the loading device 7 (FIG. 62), as described
previously.
[0300] Referring to FIG. 63 there is illustrated the loading of an
embolic protection device, which is similar to that illustrated
above in FIG. 49, into the pod 13 at the distal end 12 of the
delivery catheter 2. The loading procedure is similar to that
described above in FIGS. 59 to 62. In the case of FIG. 63, the
distal stop 72 of the pulling device 150 engages the engagement
grip 130 on the inner wall of the sleeve 43 to pull the embolic
protection device through the loading device 7 and into the
delivery catheter reception space, thereby collapsing the embolic
protection device.
[0301] FIG. 64 illustrates the loading of an embolic protection
device, which is similar to that illustrated above in FIG. 48, into
the pod 13 of the delivery catheter 2 using the pulling device
150.
[0302] Referring to FIGS. 65 to 69 there is illustrated the
retrieval of an embolic protection device, which is similar to that
described above in FIG. 48, into the retrieval catheter 3. The
retrieval procedure is similar to that described above with
reference, in particular, to FIGS. 44 to 47. In this case, the
distal stop 101 on the guidewire 99 engages the engagement grip 130
on the inner wall of the sleeve 43 to prevent the embolic
protection device moving distally relative to the distal stop 101
on the guidewire 1 during retrieval.
[0303] It will be appreciated that the engagement grip 130 may be
of any suitable configuration that facilitates engagement with the
distal stop 101 of the guidewire 99 for retrieving the deployed
embolic protection device into the retrieval catheter 3.
[0304] FIG. 70 illustrates another guidewire 160 of the embolic
protection system, which is similar to the guidewire 99 of FIGS. 1
to 69, and similar elements are assigned the same reference
numerals in FIG. 70. In this case, the guidewire 160 does not
comprise a step from a small diameter portion to a large diameter
portion.
[0305] FIGS. 71 to 74 illustrate the deployment of an embolic
protection device of the embolic protection system which has been
delivered over the guidewire 160 of FIG. 70. The delivery and
deployment procedure is similar to that described above with
reference, in particular to FIGS. 36 to 41. In this case, however,
a tapered ring 161 is provided slidably mounted on the guidewire
160 between the distal end 27 of the inner stem 28 of the inner
catheter 25 and a proximal end 163 of the embolic protection
device.
[0306] To deploy the embolic protection device at a desired
location in the vasculature 110, the delivery catheter 2 is
retracted while maintaining the position of the inner catheter 25.
The retraction of the delivery catheter 2 initially draws the
embolic protection device proximally due to the frictional force
acting between the pod 13 of the delivery catheter 2 and the
embolic protection device (FIG. 71). As the embolic protection
device is initially drawn proximally it abuts the tapered ring and
pushes the tapered ring 161 proximally until the tapered ring 161
abuts the distal end 27 of the inner stem 28 of the inner catheter
25 (FIG. 72). Further retraction of the delivery catheter 2 while
maintaining the position of the inner catheter 25 causes the
embolic protection device and the tapered ring 161 to slide
relative to one another along a tapered plane of contact 162. This
movement exerts an inward force on the tapered ring 161 to
lockingly engage the tapered ring 161 to the guidewire 160. In this
way the embolic protection device is taper-locked to the guidewire
160 by means of an interference fit between the embolic protection
device and the tapered ring 161, and by means of an interference
fit between the tapered ring 161 and the guidewire 160 (FIG. 73).
The delivery catheter 2 and the inner catheter 25 may then be
withdrawn from the vasculature 110 to leave the deployed embolic
protection device engaged to the bare guidewire 160 in place in the
vasculature 110 (FIG. 74).
[0307] The embolic protection device is retrieved in a manner
similar to that described previously with reference to FIGS. 44 to
47. The retrieval catheter 3 is advanced over the guidewire 160
until the retrieval catheter 3 is proximally adjacent the deployed
embolic protection device. The retrieval catheter 3 is then further
advanced while maintaining the position of the guidewire 160 to
collapse and retrieve the embolic protection device into the
retrieval catheter 3. Because the embolic protection device is
taper-locked to the guidewire 160 it is not necessary to provide a
distal stop on the guidewire 160 for abutment with the embolic
protection device. The taper-lock ensures no movement of the
deployed embolic protection device distally relative to the
guidewire 160 is possible, and thus facilitates retrieval of the
embolic protection device into the retrieval catheter 3. The
retrieved embolic protection device is then withdrawn from the
vasculature 110 by withdrawing the retrieval catheter 3 and the
guidewire 160 together.
[0308] Referring to FIGS. 75 to 77 there is illustrated an embolic
protection system which is similar to the embolic protection system
described above with reference to FIGS. 71 to 74, and similar
elements are assigned the same reference numerals in FIGS. 75 to
77. In this case the embolic protection system comprises two
tethers 170 with inwardly arcing hooks 172 at distal ends of the
tethers 170, the tethers 170 extending between the inner catheter
25 and the delivery catheter 2. The embolic protection device
comprises co-operating recesses 171 in the proximal end 163 of the
embolic protection device for receiving the tether hooks 172, as
illustrated in FIG. 76.
[0309] Deployment of the embolic protection device proceeds in a
manner similar to that described above with reference to FIGS. 71
to 74. During retraction of the delivery catheter 2, the tethers
170 are also retracted to ensure that the embolic protection device
is drawn proximally to effect a secure taper-lock of the embolic
protection device to the guidewire 160 (FIG. 76). The tethers 170
act in addition to the frictional force between the pod 13 of the
delivery catheter 2 and the embolic protection device to draw the
embolic protection device proximally.
[0310] After deployment and taper-locking of the embolic protection
device, the hooks 172 of the tethers 170 are unclipped by advancing
the inner catheter 25 (FIGS. 76 and 77). The distal end 27 of the
inner stem 28 of the inner catheter 25 engages the hooks 172 and
levers the hooks 172 outwardly disengaging the hooks 172 from the
co-operating recesses 171 (FIG. 77). The tethers 170 and the inner
catheter 25 are then withdrawn from the vasculature 110 to leave
the deployed embolic protection device in place in the vasculature
110 taper-locked to the bare guidewire 160.
[0311] Referring to FIGS. 78 to 81 there is illustrated a rapid
exchange embolic protection system which is similar to the embolic
protection systems of FIGS. 1 to 77, and similar elements are
assigned the same reference numerals in FIGS. 78 to 81. In this
case, the pod 13 of the delivery catheter 2 comprises an elongate
slit 180 and the inner stem 28 of the inner catheter 25 comprises a
rapid exchange aperture 181 for passage of a guidewire 182 through
the aperture 181 and the slit 180 (FIG. 78).
[0312] The embolic protection device is delivered to a desired
location in the vasculature 110 distally of the stenosed region 111
(FIG. 78) in a manner similar to that described previously with
reference to FIGS. 36 and 37. The embolic protection device is
deployed by retracting the delivery catheter 2 while maintaining
the position of the inner catheter 25 (FIGS. 79 to 81), which
facilitates deployment of the embolic protection device in a manner
similar to that described previously with reference to FIGS. 38 and
39.
[0313] The slit 180 in the pod 13 of the delivery catheter 2 is
aligned with the rapid exchange aperture 181 in the stem 28 of the
inner catheter 25 to prevent occlusion of the rapid exchange
aperture 181 during the relative movement of the delivery catheter
2 and the inner catheter 25.
[0314] The aperture 181 provided in a sidewall of inner stem 28 of
inner catheter is preferably located at a position along the length
of the inner catheter which is spaced a relatively longer distance
from the proximal end of the catheter than from the distal end of
the catheter. Additionally, delivery catheter 2 desirably
incorporates an elongate slit 180 which is located adjacent the
distal end the catheter and co-operates with aperture 181 and the
guide wire 182 which exits therethrough to facilitate a rapid
exchange of the catheter and filter assembly over the guide wire,
thereby promoting ease of exchange without the necessity of
utilising exchange wires or extension wires. As illustrated in
FIGS. 78-81, this arrangement permits use of rapid exchange wire
techniques as well as controlled deployment and retrieval of the
filter at the delivery pod portion 13 located at the distal end of
delivery catheter 2.
[0315] This is advantageous in that it facilitates single operator
use. A shorter guidewire may be used than for conventional systems
making the device less cumbersome.
[0316] Referring now to FIG. 82 there is illustrated another
embolic protection system 200 according to the invention. The
system is similar to these described above and like parts are
assigned the same reference numerals. In this case the guidewire 99
includes a proximal stop provided by a step 201 and the filter has
a proximal engagement element provided by integral projections 202
which extend radially inwardly. The projections 202 are configured
to pass over the proximal step 201 when the filter element is being
moved distally over the guidewire 99 for deployment but are
prevented from moving proximally over the proximal step 201. Thus,
the filter element, on deployment can move between the proximal and
distal stops on the guidewire. The arrangement may allow the filter
to be retrieved over the proximal step 202.
[0317] Referring to FIG. 83 there is illustrated a system 205
similar to that of FIG. 82 and like parts are assigned the same
reference numerals. In this case the proximal step on the guidewire
is provided by a proximally tapering element 206.
[0318] The embolic protection device is not restricted to use with
a particular guidewire because it is not attached or engaged with
the guidewire in any way as it is advanced over the guidewire. This
is a highly advantageous arrangement. If the guidewire proves
unsuitable for some reason, for example because it is too large or
not trackable enough to access a desired site in a vascular system,
the guidewire may be replaced with a more suitable guidewire, for
example a guidewire with greater flexibility. However, because the
embolic protection device is independent of the guidewire it may be
used with any suitable guidewire.
[0319] The invention gives greater freedom to a user by providing a
choice of guidewires to suit a patient anatomy without requiring
the user to select the embolic protection device to be used with
the guidewire until after successful crossing of a lesion with the
guidewire.
[0320] Numerous vascular catheter functions are facilitated by the
invention, such as:
(i) Permits Dye Injections:
[0321] After performing a therapeutic procedure (e.g. angioplasty
or atherectomy), the embolic protection device can be retrieved if
desired, in order to inject dye (over the remaining guidewire),
such that minimal obstruction or interference occurs with the
subsequent dye flow measurements. Alternatively, the wire can also
be safely partially-retracted "behind" or "upstream" of the treated
area, prior to performing the dye injection.
(ii) Delivery of Lytic Agents:
[0322] Depending upon therapeutic needs, lytic agents can be
site-specifically delivered to a region of interest, either with
the embolic protection device deployed, or with the embolic
protection device retrieved, if desired.
(iii) Facilitates Stent Procedures:
[0323] Assuming appropriate design considerations have been
incorporated, the retrieval sheath can also facilitate safe removal
of the embolic protection device following a stenting procedure.
For example, after deployment of an intravascular stent, the
process of removing the embolic protection device favours certain
sheath designs, such as a tapered distal tip. Specifically, the
distal tip of the sheath needs to permit easy crossing of the stent
in a manner which will not catch up or "snag" at the proximal edge
of the implanted stent, nor along any inwardly-projecting surface
of the interior of the implanted stent, as the sheath is being
introduced. More specifically, the distal region of the retrieval
sheath is also preferably formed of a material which permits radial
expansion at the distal tip in order to accommodate retrieval of
the embolic protection device.
(iv) Facilitates Guidewire Replacements:
[0324] Because this embolic protection system accommodates barewire
introduction, it is possible to replace a guidewire during a
procedure, if desired. For example, during treatment of two or
more, distally spaced-apart lesions, it may become necessary to
replace the initial guidewire during the procedure with another
guidewire offering improved steering or distal flexibility. The
present invention might support such guidewire replacements as
follows. First, the embolic protection device is retrieved into the
retrieval sheath (which has already crossed the first lesion area).
Then the wire can be withdrawn (or alternatively, the wire and
embolic protection device together can be withdrawn), while the
sheath remains across the lesion. Subsequently, a replacement
guidewire can be introduced through the sheath lumen to the area of
interest.
[0325] A number of engagement means between the embolic protection
device and the guidewire are described above which ensure that the
embolic protection device is anchored or tethered while the
retrieval sheath is advanced over the embolic protection device. It
is also envisaged that an engagement means may be provided between
the embolic protection device and the retrieval sheath after the
filter is retrieved, to ensure that there is a positive engagement
between the embolic protection device and the sheath. For example,
frictional engagement means may be provided on one or both of the
embolic protection device and sheath. For example, projections,
rings, or the like may be provided on the inner surface of the
retrieval sheath adjacent the distal end thereof to provide a
frictional fit with the retrieved embolic protection device.
Typical arrangements 210, 220 of this type are illustrated in FIGS.
84 and 85. The frictional engagement may be provided by projections
225 which may be of any type including continuous, discontinuous,
radially and/or longitudinally extending.
[0326] The invention is not limited to the embodiments hereinbefore
described, which may be varied in construction and detail.
* * * * *