U.S. patent application number 12/190319 was filed with the patent office on 2008-12-04 for vasculara device for emboli, thrombus and foreign body removal and methods of use.
This patent application is currently assigned to INCEPT LLC. Invention is credited to Jackson F. Demond, Leo N. Hopkins, Farhad Khosravi, Jeff A. Krolik, Jonah Lepak, Stephen Ramee, Richard Renati, Amr Salahieh.
Application Number | 20080300621 12/190319 |
Document ID | / |
Family ID | 24550140 |
Filed Date | 2008-12-04 |
United States Patent
Application |
20080300621 |
Kind Code |
A1 |
Hopkins; Leo N. ; et
al. |
December 4, 2008 |
VASCULARA DEVICE FOR EMBOLI, THROMBUS AND FOREIGN BODY REMOVAL AND
METHODS OF USE
Abstract
Apparatus and methods are provided for use in filtering emboli
from a vessel and/or performing thrombectomy and embolectomy,
wherein a vascular device comprises one or more support hoops
connected near a distal end of a guide wire, each support hoop
having an articulation region, and a blood permeable sac affixed to
the support hoop or hoops to form a mouth of the blood permeable
sac. The mouth of the sac closes when the apparatus is collapsed
for removal to prevent material from escaping from the sac.
Inventors: |
Hopkins; Leo N.; (Buffalo,
NY) ; Khosravi; Farhad; (San Mateo, CA) ;
Salahieh; Amr; (Campbell, CA) ; Demond; Jackson
F.; (Santa Cruz, CA) ; Lepak; Jonah; (Santa
Cruz, CA) ; Ramee; Stephen; (New Orleans, LA)
; Krolik; Jeff A.; (Campbell, CA) ; Renati;
Richard; (San Jose, CA) |
Correspondence
Address: |
CROMPTON, SEAGER & TUFTE, LLC
1221 NICOLLET AVENUE, SUITE 800
MINNEAPOLIS
MN
55403-2420
US
|
Assignee: |
INCEPT LLC
San Mateo
CA
|
Family ID: |
24550140 |
Appl. No.: |
12/190319 |
Filed: |
August 12, 2008 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
10302433 |
Nov 22, 2002 |
7410491 |
|
|
12190319 |
|
|
|
|
09636040 |
Aug 9, 2000 |
6544279 |
|
|
10302433 |
|
|
|
|
09364064 |
Jul 30, 1999 |
6530939 |
|
|
09636040 |
|
|
|
|
Current U.S.
Class: |
606/200 |
Current CPC
Class: |
A61B 2017/2212 20130101;
A61M 2025/1052 20130101; A61F 2002/018 20130101; A61M 25/0069
20130101; A61F 2230/0008 20130101; A61F 2/013 20130101; A61B
2017/00287 20130101; A61F 2/01 20130101; A61F 2/011 20200501; A61F
2230/008 20130101; A61M 2025/09183 20130101; A61M 2025/109
20130101 |
Class at
Publication: |
606/200 |
International
Class: |
A61M 29/02 20060101
A61M029/02 |
Claims
1. An embolic protection filtering device, comprising: an elongate
shaft having a proximal region and a distal region; a filter
affixed to the shaft adjacent the distal region; a nose assembly
having a proximal end and a distal end, the nose assembly affixed
to the shaft adjacent to and distal of the filter; and a delivery
sheath slidably disposed over the elongate shaft, the delivery
sheath having a first outer diameter along a majority of its
length, wherein the nose assembly has a diameter at its proximal
end substantially equal to the first outer diameter of the delivery
sheath.
2. The device of claim 1 wherein the nose assembly tapers from the
proximal end diameter to a smaller diameter at its distal end.
3. The device of claim 1 wherein the nose assembly curves from the
proximal end diameter to a smaller diameter at its distal end.
4. The device of claim 1 wherein the delivery sheath includes a
first lumen for the filter and a second lumen for a guidewire.
5. The device of claim 4 wherein the second lumen is the same
length as the first lumen.
6. The device of claim 4 wherein the second lumen is shorter than
the first lumen.
7. The device of claim 4 wherein the nose assembly includes a
guidewire lumen.
8. The device of claim 1 wherein the filter includes a hoop and a
blood permeable sac.
9. The device of claim 1 wherein the delivery sheath includes a
hemostatic fitting.
10. The device of claim 1 wherein the shaft extends distally from
the nose assembly.
11. Apparatus for deploying and retrieving a vascular device
disposed on an elongated member from within a lumen of a delivery
sheath, the apparatus comprising: means for selectively grasping
and releasing the elongated member; and a lumen flushing section
coupled to the handle to allow translation and rotation
therebetween, the lumen flushing section having a side port in
fluid communication with the lumen of the delivery sheath and
configured to allow the elongated member to pass therethrough to
the handle.
12. The apparatus of claim 11, wherein the vascular device further
comprises a support hoop attached to a distal region of the
elongated member, the support hoop having an articulation region
interposed between curved regions, and a blood permeable sac
affixed to the support hoop so that the support hoop forms a mouth
of the blood permeable sac.
13. Apparatus for filtering emboli or performing thrombectomy or
embolectomy, comprising: an elongated member having a distal
region; first and second support hoops coupled to the distal
region, each one of the first and second support hoops having an
articulation region disposed between curved regions; and a blood
permeable sac affixes at its proximal end to the first and second
support hoops so that the first and second support hoops define at
least in part a proximally facing opening of the blood permeable
sac.
14. The apparatus of claim 13 further comprising a third support
hoop.
15. The apparatus of claim 14 wherein the blood permeable sac is
affixed at its proximal end to the third support hoop.
16. The apparatus of claim 13 wherein each support hoop comprises a
wire having a thickness that tapers to a minimum thickness at the
articulation region.
17. The apparatus of claim 13 wherein the support hoops are folded
at their respective articulation regions when the apparatus is in a
contracted state.
18. The apparatus of claim 13 wherein the opposite sides of each
support hoop close towards one another when the apparatus is in a
contracted state.
19. Apparatus for filtering emboli or performing thrombectomy or
embolectomy, the apparatus comprising: an elongated member having a
distal region; a support hoop coupled to the distal region; and a
blood permeable having a first and second thickness of a material
at its proximal end to define a lumen between the first and second
thicknesses, wherein the support hoop is disposed in the lumen.
20. The apparatus of claim 1 wherein the support hoop includes an
articulation region comprising a gap interposed between curved
spines.
21. The apparatus of claim 1 wherein the material of the blood
permeable sack includes a plurality of pores having a diameter in a
range of 20 to 400 microns.
Description
REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 10/302,433 filed Nov. 22, 2002, which claims the benefit of
U.S. patent application Ser. No. 09/636,040 filed on Aug. 9, 2000,
U.S. patent application Ser. No. 09/364,064 filed Jul. 30, 1999,
U.S. patent application Ser. No. 09/430,211 filed Oct. 29, 1999,
U.S. patent application Ser. No. 09/470,681 filed Dec. 23, 1999,
U.S. patent Ser. No. 09/470,682 filed Dec. 23, 1999, U.S. patent
application Ser. No. 09/470,703 filed Dec. 23, 1999, U.S. patent
application Ser. No. 09/470,857 filed Dec. 23, 1999, and U.S.
patent application Ser. No. 09/611,428 filed Jul. 7, 2000, all of
which are incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to apparatus and methods for
filtering or removing matter from within a vascular system. More
particularly, the present invention provides a low profile
self-expanding vascular device useful for capturing emboli or
foreign bodies generated during interventional procedures, and for
thrombectomy and embolectomy.
BACKGROUND OF THE INVENTION
[0003] Percutaneous interventional procedures to treat occlusive
vascular disease, such as angioplasty, atherectomy and stenting,
often dislodge material from the vessel walls. This dislodged
material, known as emboli, enters the bloodstream, and may be large
enough to occlude smaller downstream vessels, potentially blocking
blood flow to tissue. The resulting ischemia poses a serious threat
to the health or life of a patient if the blockage occurs in
critical tissue, such as the heart, lungs, or brain.
[0004] The deployment of stents and stent-grafts to treat vascular
disease, such as aneurysms, also involves the introduction of
foreign objects into the bloodstream, and also may result in the
formation of clots or release of emboli. Such particulate matter,
if released into the bloodstream, also may cause infarction or
stroke.
[0005] Furthermore, interventional procedures may generate foreign
bodies that are left within a patient's bloodstream, thereby
endangering the life of the patient. Foreign bodies may include,
for example, a broken guide wire, pieces of a stent, or pieces of a
catheter.
[0006] Numerous previously known methods and, apparatus have been
proposed to reduce complications associated with embolism, release
of thrombus, or foreign body material generation. U.S. Pat. No.
5,833,644 to Zadno-Azizi et al., for example, describes the use of
a balloon-tipped catheter to temporarily occlude flow through a
vessel from which a stenosis is to be removed. Stenotic material
removed during a treatment procedure is evacuated from the vessel
before the flow of blood is restored. A drawback of such previously
known systems, however, is that occlusion of antegrade flow through
the vessel may result in damage to the tissue normally fed by the
blocked vessel.
[0007] U.S. Pat. No. 5,814,064 to Daniel et al. describes an emboli
filter system having a radially expandable mesh filter disposed on
the distal end of a guide wire. The filter is deployed distal to a
region of stenosis, and any interventional devices, such as
angioplasty balloons or stent delivery systems, are advanced along
the guide wire. The filter is designed to capture emboli generated
during treatment of the stenosis while permitting blood to flow
through the filter. Similar filter systems are described in U.S.
Pat. No. 4,723,549 to Wholey et al. and U.S. Pat. No. 5,827,324 to
Cassell et al.
[0008] One disadvantage of radially expandable filter systems such
as described in the foregoing patents is the relative complexity of
the devices, which typically comprise numerous parts. Connecting
more than a minimal number of such parts to a guide wire generally
increases delivery complications. The ability of the guide wire to
negotiate tortuous anatomy is reduced, and the profile of the
device in its delivery configuration increases. Consequently, it
may be difficult or impossible to use such devices in small
diameter vessels, such as are commonly found in the carotid artery
and cerebral vasculature. Moreover, such filter devices are
generally incapable of preventing material from escaping from the
filter during the process of collapsing the filter for removal.
[0009] International Publication No. WO 98/39053 describes a filter
system comprising an elongated member, a radially expandable hoop
and a cone-shaped basket. The hoop is affixed to the elongated
member, and the cone-shaped basket is attached to the hoop and the
elongated member, so that the hoop forms the mouth of the basket.
The filter system includes a specially configured delivery catheter
that retains the mouth of the basket in a radially retracted
position during delivery.
[0010] While the filter system described in the foregoing
International Publication reduces the number of components used to
deploy the cone-shaped basket, as compared to the radial strut-type
filter elements described hereinabove, it too has drawbacks. Chief
among these, it is expected that it will be difficult to reduce the
diameter of the radially expandable hoop to its retracted position.
In particular, as the hoop is contracted through smaller radii of
curvature, the stiffness of the hoop is expected to increase
dramatically. This increased stiffness prevents the hoop from being
contracted more tightly, and is expected to result in a delivery
profile too large to permit use of the device in critical regions
of the body, such as the smaller coronary arteries, carotid
arteries, and cerebral vasculature.
[0011] In view of the foregoing disadvantages of previously known
apparatus and methods, it would be desirable to provide a vascular
device, e.g., for use as a vascular filter, that overcomes such
disadvantages and employs few components.
[0012] It would be desirable to provide a reliable and
multi-functional delivery system for use with the vascular
device.
[0013] It would be desirable to provide an integrated vascular
device with a thrombectomy element and a vascular filter.
[0014] It also would be desirable to provide a vascular device that
is capable of being contracted to a small delivery profile, thus
permitting use of the device in small vessels.
[0015] It further would be desirable to provide a vascular device
that is capable of being contracted to a sufficiently small profile
that it may be retrieved using the guide wire lumen of previously
known treatment devices, and without the need for specialized
delivery catheters.
[0016] It still further would be desirable to provide a vascular
device that reduces the risk of emboli or thrombus removed from the
vessel wall escaping from the device when the device is collapsed
and removed.
[0017] It also would be desirable to provide a vascular device that
permits a rapid exchange deployment modality.
SUMMARY OF THE INVENTION
[0018] In view of the foregoing, it is an object of the present
invention to provide a vascular device that overcomes disadvantages
of previously known vascular filters, thrombectomy/embolectomy and
foreign body removal devices, and employs few components.
[0019] It is an object of the present invention to provide a
reliable and multi-functional delivery system for use with the
vascular device.
[0020] It is an object to provide an integrated vascular device
with a thrombectomy element and a vascular filter.
[0021] It also is an object of this invention to provide a vascular
device that is capable of being contracted to a small delivery
profile, thus permitting use of the device in small vessels.
[0022] It is a further object to provide a vascular device that is
capable of being contracted to a sufficiently small profile that it
may be retrieved using the guide wire lumen of previously known
treatment devices, and without the need for specialized delivery
catheters.
[0023] It is another object to provide a vascular device that
reduces the risk of emboli or thrombus removed from the vessel wall
escaping from the device when the device is collapsed and
removed.
[0024] It also is an object to provide a vascular device that
permits a rapid exchange deployment modality.
[0025] These and other objects of the present invention are
accomplished by providing a vascular device, suitable for use as a
vascular filter or thrombectomy/embolectomy device that comprises a
blood permeable sac affixed at its perimeter to a support hoop
having an articulation region. The support hoop is attached to a
distal region of an elongated member, such as a guide wire, and
supports a proximally-oriented mouth of the sac when the device is
deployed in a vessel. The device may also comprise a nose cone to
facilitate percutaneous introduction, and a delivery sheath having
one or more lumens. The lumens may further be configured for a
rapid exchange mode of introduction along the guide wire.
[0026] In a first embodiment, the support hoop includes one or more
reduced-thickness articulation regions that enable the support hoop
to be contracted to very small radii of curvature without the
problems of increased stiffness and kinking of previously known
devices. In an alternative embodiment, the articulation region may
comprise a gap in the support hoop bridged by the perimeter of the
blood permeable sac.
[0027] The support hoop preferably also has a curved profile that
prevents the articulation region, when folded, from damaging the
wall of the vessel. The curved profile permits the device to
effectively contact the walls of the vessel and reduce emboli or
thrombus removed from the vessel wall from bypassing the sac.
Moreover, the articulation region, when combined with a support
hoop having a curved profile, causes the sides of the support hoop
to fold inwards towards one-another when the vascular device is
collapsed into a sheath for removal. This, in turn, closes the
mouth of the sac and reduces the potential for emboli or thrombus
to be released from the vascular device during removal.
[0028] Advantageously, use of an articulation region permits
vascular devices of the present invention to be contracted to very
small diameters, thereby enabling the use of delivery catheters
having diameters as small as 3 Fr. Moreover, the vascular devices
may be retracted within the guide wire lumens of conventional
treatment devices, such as angioplasty catheters and stent delivery
systems, thereby obviating the need to re-insert a specialized
delivery catheter to remove the vascular device. However, a
retrieval sheath having a distal region that flares or expands
outwardly to receive the emboli-filled sac upon completion of an
interventional procedure, and which reduces risk of rupture to the
sac, optionally may be provided in accordance with the present
invention.
[0029] In embodiments suitable for use as embolic filters, the
vascular device may include a separate guide wire for introducing
treatment devices proximal of the deployed vascular device.
Additionally, the vascular device may have a second support hoop
attached to the distal end of the sac. During retrieval, multiple
hoops ensure that emboli are retained within the sac and prevent
the sac from bunching. Where multiple hoops are rotated, they may
be arranged such that they rotate independently of the guide wire,
thereby reducing risk that the sac wall will become twisted during
advancement.
[0030] In alternative embodiments, sac bunching is mitigated by
tapering the sac and attaching it to one or more support hoops, or
to the guide wire. Sac porosity may also be specified to ensure
passage of blood cells and capture of emboli, as well as to control
a pressure drop across the vascular device. In other embodiments, a
delivery sheath is provided that permits a lesion to first be
crossed with an unencumbered guide wire prior to passing the
vascular device across the lesion. In still further embodiments,
several support hoops may be provided at the mouth of a single sac
to facilitate opening and closing of the sac.
[0031] In thrombectomy applications, a separate thrombectomy
element may be provided in addition to the vascular filter. The
thrombectomy element may be attached to the elongated member
proximal of the vascular filter or may comprise a separate
catheter. In a preferred embodiment, the thrombectomy element is
similar in construction to the vascular filter and may be retracted
independently. Alternatively, the thrombectomy element may be any
conventional atherectomy device used in conjunction with the
vascular filter and may be advanced and retracted either in
conjunction or independently of the vascular filter.
[0032] A delivery system in accordance with the present invention,
configured for use with the vascular devices described herein, is
also provided. The delivery system integrates the functions of a
Touhy Borst, a torquer, and a pusher into a single device, thereby
facilitating introduction and retrieval of embodiments of the
present invention. The torqueing function allows a vascular device
to navigate tortuous anatomy. For example, the distal end of a
guide wire may be rotated to selectively orient the vascular device
in a selected branch of a bifurcated vessel. The Touhy-Borst
adapter permits liquid to be introduced or withdrawn through the
lumen of the vascular device delivery catheter. The pusher feature
of the delivery system allows deployment and retraction of the
vascular device from within the delivery catheter.
[0033] Methods of using embodiments of the present invention are
also provided, including use of novel radiopaque features, and use
of a previously known balloon catheter to arrest antegrade flow
through a vessel until the vascular device of the present invention
is deployed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0034] The above and other objects and advantages of the present
invention will be apparent upon consideration of the following
detailed description, taken in conjunction with the accompanying
drawings, in which like reference characters refer to like parts
throughout, and in which:
[0035] FIGS. 1A and 1B are, respectively, a side-sectional view of
a previously known vascular device contracted within a delivery
sheath, and an end view of that vascular device deployed in a
vessel;
[0036] FIGS. 2A and 2B are, respectively, a perspective view of a
vascular device constructed in accordance with the principles of
the present invention in a deployed state, and a detailed view of
the articulation region of the device of FIG. 2A;
[0037] FIG. 3 is a perspective view of the vascular device of FIG.
2 in a folded configuration, prior to removal;
[0038] FIG. 4 is a plan view of the vascular device of FIG. 2;
[0039] FIGS. 5A-5D are side sectional views depicting a method of
deploying, using, and retrieving the vascular device of FIGS.
2-4;
[0040] FIG. 6 is a perspective view of an alternative embodiment of
a vascular device of the present invention in a deployed state;
[0041] FIGS. 7A and 7B are, respectively, a perspective view and a
plan view of a further alternative embodiment of the present
invention in a deployed state;
[0042] FIGS. 8A-8E are sectional views of a vascular device
disposed within alternative embodiments of delivery sheaths of the
present invention;
[0043] FIG. 9 is a side view of a previously known balloon
catheter;
[0044] FIGS. 10A-10D are views illustrating the steps of using the
balloon catheter of FIG. 9 with the vascular device of FIG. 2;
[0045] FIGS. 11A-11C are perspective views of further alternative
embodiments of vascular devices constructed in accordance with the
principles of the present invention;
[0046] FIG. 12 is a perspective view of an alternative embodiment
of the vascular device of the present invention with two support
hoops, shown in a deployed state;
[0047] FIG. 13 is a perspective view of an alternative embodiment
of the vascular device of FIG. 12 with a smaller distal support
hoop;
[0048] FIG. 14 is a perspective view of a still further alternative
embodiment of the vascular device of FIG. 12 that allows the
vascular device to independently rotate with respect to the guide
wire;
[0049] FIG. 15 is a perspective view of an alternative embodiment
of the present invention with a tapered blood permeable sac, shown
in a deployed state;
[0050] FIG. 16 is a perspective view of a radiopaque support hoop
constructed in accordance with one aspect of the present
invention;
[0051] FIGS. 17A-17C illustrate another alternative embodiment of
the vascular device of the present invention in which the
articulation region comprises a gap in the support hoop bridged by
the perimeter of the blood permeable sac;
[0052] FIGS. 18A and 181B are side-sectional views depicting an
integrated vascular device of the present invention suitable for
thrombectomy, disposed, respectively, within a delivery sheath and
in a deployed state;
[0053] FIGS. 19A-19E are side-sectional views depicting a method of
deploying, using, and retrieving the integrated vascular device of
FIG. 18;
[0054] FIGS. 20A and 20B are side-sectional views depicting an
alternative embodiment of the integrated vascular device of FIG.
18, disposed, respectively, within a delivery sheath and in a
deployed state;
[0055] FIGS. 21A and 211B are side sectional views of a delivery
system constructed in accordance with the present invention coupled
to the vascular device of FIG. 5A, shown, respectively, in a
delivery configuration and in a deployed configuration;
[0056] FIGS. 22A-22E are side sectional views depicting a method of
deploying, using, and retrieving a vascular device of the present
invention in conjunction with a specially configured retrieval
sheath; and
[0057] FIGS. 23A and 23B are side sectional views depicting a
method of using and retrieving the vascular device in conjunction
with an alternative embodiment of the specially configured
retrieval sheath.
DETAILED DESCRIPTION OF THE INVENTION
[0058] Referring to FIGS. 1A and 1B, some of the disadvantages
associated with previously known vascular devices, such as the
emboli filters described in the above-mentioned International
Publication WO 98/39053, are described. In FIG. 1, the vascular
filter comprises guide wire 10 having hoop 12 coupled to its end.
Filter sac 14 is affixed to hoop 12, so that when delivery catheter
16 is retracted proximally and guide wire 10 is held stationary,
hoop 12 radially expands to contact the walls of vessel V.
[0059] As described hereinabove, one difficulty with such vascular
filters is that the hoop used to support the filter sac experiences
increased stiffness when contracted to small diameters, i.e., due
to the sharp directional change at the tip of the hoop, thereby
limiting the minimum delivery profile achievable for such
instruments. Although this effect may be reduced by decreasing the
thickness of the wire employed in hoop 12, at the point at which
the wire becomes sufficiently thin to accommodate the bending
stresses, the wire is too thin to effectively radially expand and
urge the filter sac into engagement with the vessel wall.
[0060] On the other hand, as shown in FIGS. 1A and 1B, the bending
stresses imposed upon the hoop of such previously known devices, if
drawn within a delivery catheter, may be sufficiently high to
result in the formation of kink 18 at the tip of the hoop. This
"kinking" effect becomes more severe in sheaths having a small
inner diameter. Thus, for example, applicant has observed that when
sheaths having inner diameters of 0.035'' or smaller are used, a
hoop of nitinol or multi-strand nitinol cable having a diameter of
0.0055'' will form kink 18. Kink 18 in turn may apply relatively
high localized pressure and friction against wall 17 of sheath 16,
thereby making the vascular filter difficult to deploy. In
particular, the kink may impale wall 17 of delivery sheath 16 and
may make it difficult or impossible to deploy the vascular filter,
especially in tortuous anatomy.
[0061] In addition, when the filter is subsequently deployed in
vessel V, as shown in FIG. 1B, kink 18 may deform the pre-formed
shape of hoop 12, impairing the ability of the filter to seal
against the walls of vessel V. This may in turn lead to the
presence of gaps G between the perimeter of the hoop and the vessel
wall, depending upon the severity of the kink. Consequently, emboli
may pass through the gaps with antegrade flow and significantly
reduce the efficacy of the filter. Additionally, kink 18 may be
sufficiently sharp to damage or dissect the wall of vessel V when
the filter is deployed.
[0062] The vascular device of the present invention solves the
above-described disadvantages, providing a vascular device,
suitable for use as a vascular filter or thrombectomy/embolectomy
device, with a self-expanding support hoop that is sufficiently
thick to radially expand and urge a blood permeable sac into
engagement with the vessel wall, but which includes an articulation
region that overcomes the problems associated with kinking. In
particular, the vascular device of the present invention includes a
reduced thickness articulation region and a pre-formed curved
profile that avoids the difficulties of previously known systems
while providing a high degree of efficacy in capturing emboli or
thrombus, and ease of deployment and retrieval.
[0063] Referring now to FIGS. 2A and 2B, vascular device 20
constructed in accordance with the principles of the present
invention, illustratively an embolic filter, comprises guide wire
22, support hoop 24 having articulation region 26, and blood
permeable sac 28 affixed to support hoop 24. Sac 28 is coupled to
support hoop 24 so that the support hoop 24 forms an opening for
the sac. Support hoop 24 preferably is connected to guide wire 22
near distal end 23 of the guide wire.
[0064] Sac 28 preferably is constructed of a thin, flexible
biocompatible material, such as polyethylene, polypropylene,
polyurethane, polyester, polyethylene tetraphlalate, nylon or
polytetrafluoroethylene, or combinations thereof. The material
should be sufficiently thin, such that the sac is non-thrombogenic.
Sac 28 includes openings or pores 30 that permit blood cells to
pass through the sac substantially unhindered, while capturing any
larger emboli, thrombus, or foreign bodies that may be released
during a procedure, such as angioplasty or stent placement. In a
preferred embodiment, sac 28 has openings or pores 30 in a range of
about 20 to 400 microns in diameter, and more preferably, about
approximately 80 microns. These pore sizes permit red blood cells
(which have a diameter of approximately 5 microns) to easily pass
through the sac, while capturing thrombus or emboli.
[0065] Pores 30 are preferably formed by a laser drilling process.
For example, a thin sheet of the flexible biocompatible material
may be thermoformed to create sac 28, for example, by stretching
the sheet over a mandrel, by dip forming, or by blow molding. Sac
28 may alternatively be fabricated from an extruded tube of the
biocompatible material. A flat metal mask, with tiny holes
approximately the size of pores 30, may then be placed in front of
the sac. A laser having a beam diameter equal to or greater than
the diameter of the material illuminates the mask. The laser beam
passes through the holes in the mask and strikes the material,
thereby forming pores 30 in sac 28.
[0066] Laser drilling may also be accomplished with a laser having
a beam diameter approximately the size of pores 30, in which case
pores 30 may drilled individually. Sac 28 may alternatively
comprise a woven material, for example, formed from the
above-mentioned polymers, having a pore diameter determined as a
function of the pattern and tightness of the weave.
[0067] Support hoop 24 comprises a hoop having a circular or
rectangular cross-section that is formed of a super-elastic
material, such as a nickel-titanium alloy ("nitinol"). During
deployment and retrieval of vascular device 20, described
hereinafter, support hoop 24 folds in half and collapses to fit
within a small diameter delivery sheath. When vascular device 20 is
in a deployed state, as depicted in FIG. 2A, support hoop 24
resumes its pre-formed shape. Support hoop 24 preferably comprises
nitinol wire, although it may also be formed from a multi-strand
nitinol cable, a spring tempered stainless steel, or other
super-elastic material.
[0068] In accordance with the principles of the present invention,
support hoop 24 includes one or more reduced-thickness articulation
regions 26, and pre-formed curved regions 34. As depicted in FIG.
2B, articulation region 26 includes a region having reduced
thickness t.sub.1 compared to thickness t of the remainder of
support hoop 24. Articulation region 26 and curved regions 34
enable support hoop 24 to fold with a pre-determined shape when
vascular device 20 is collapsed to a contracted state for delivery
or retrieval.
[0069] In FIG. 2B, articulation region 26 is depicted as a
localized reduction in the thickness of support hoop 24, as may be
achieved, for example, using conventional grinding, chemical
etching, or electroless polishing processes. Alternatively, support
hoop 24 may be continuously tapered along its circumference, so
that articulation region 26 results from a more gradual reduction
in the wall thickness of the support hoop. Tapering support hoop 24
may permit greater flexibility in the vicinity of articulation
region 26, thus enabling support hoop 24 to fold more easily at the
articulation region. Such tapering of the thickness of the support
hoop along a portion of its circumference also may reduce the
potential for stress-induced fracture typically associated with
abrupt changes in diameter.
[0070] In a preferred embodiment of vascular device 20 of the
present invention, vascular device 20 easily fits within a delivery
sheath having an inner diameter of 0.033'', and, more preferably,
may be used with a delivery sheath having an inner diameter as
small as 0.026''. The deployed diameter of support hoop 24
preferably is approximately 7 mm, while guide wire 22 preferably
has a diameter of 0.014''. The distal end of guide wire 22 also may
be tipped with a spring section or coil tip, as is per se
known.
[0071] Support hoop 24 preferably is constructed of 0.00551''
nitinol wire tapered (by a grinding, chemical etching, or
electroless polishing process) to 0.0025'' at articulation region
26. Specifically, articulation region 26 preferably consists of a
length about 0.05'' long and having a diameter of 0.0025'', coupled
on either side to curved regions 34. Each of curved regions 34
includes a length of wire that is tapered from a diameter of
0.055'' to a diameter of 0.0025'' over a length of about 0.025''.
Support hoop 24 also may include radiopaque features, such as gold
or platinum bands 33, spaced at intervals around the circumference
of support hoop 24, or a coil of radiopaque material wrapped around
the support hoop, as described hereinafter with respect to FIG. 16,
or a gold plated coating.
[0072] Referring to FIGS. 3 and 4, additional features of vascular
device 20 are described. FIG. 3 depicts vascular device 20 of FIG.
2A in a contracted state, while FIG. 4 illustrates a directional
change in support hoop 24 preferably caused by the presence of
curved regions 34. Advantageously, use of articulation region 26
and the curved profile of support hoop 24 introduced by curved
regions 34 also cause support hoop 24 to fold in half during
retrieval. As shown in FIG. 3, support hoop 24 folds in half,
effectively closing the mouth of blood permeable sac 28 and
preventing the escape of collected emboli or thrombus. This feature
also may permit the use of a smaller or shallower sac than would
otherwise be possible, without increasing the risk of material
escaping from the device when the sac is collapsed for retrieval.
Use of a smaller or shallower sac also enables vascular device 20
to be delivered in a smaller delivery sheath, having an inner
diameter as small as 0.026'' for the preferred embodiment.
[0073] Referring now to FIGS. 5A-5D, methods of using the vascular
device of the present invention as a vascular filter are described.
In FIG. 5A, guide wire 22 and delivery sheath 40 are manipulated
into position within vessel V using well-known percutaneous,
techniques. Vascular device 20 of FIG. 2A is disposed in its
contracted delivery state within distal end 42 of delivery sheath
40, and delivery sheath 40 is advanced through the vessel using
distal end 23 of guide wire 22. Articulation region 26 and curved
regions 34 of support hoop 24 enable the sides of the support hoop
to fold together and become elongated when drawn within delivery
sheath 40. The size of delivery sheath 40 and guide wire 22 have
been exaggerated to illustrate structure. In reality, the diameter
of delivery sheath 40 is approximately an order of magnitude
smaller than the internal diameter of vessel V.
[0074] With respect to FIG. 5B, once delivery sheath 40 is disposed
at a desired location within a patient's vessel V, such as a
coronary artery or carotid artery, as determined, for example, by
the position of radiopaque band 43 under a fluoroscope, guide wire
22 is held stationary while delivery sheath 40 is retracted
proximally. Alternatively, delivery sheath 40 may be held
stationary while guide wire 22 is advanced. In either case, when
vascular device 20 is no longer confined within delivery sheath 40,
support hoop 24 expands to seal against the walls of vessel V. When
in its deployed state, curved regions 34 of support hoop 24 orient
articulation region 26 concentrically against the inside wall of
the vessel, thus reducing the risk of impaling the vessel wall, as
might be expected of the kinked support hoop of FIG. 1B. Blood
continues to flow unimpeded through vessel V in direction D.
[0075] In FIG. 5C, once vascular device 20 is deployed in vessel V,
other interventional instruments, such as angioplasty catheters,
atherectomy devices, or stent delivery systems may be advanced
along guide wire 22 to position such devices at treatment zones
located proximally of vascular device 20. For example, in FIG. 5C,
angioplasty balloon catheter 44 has been advanced along guide wire
22 to a position proximal of vascular device 20 to trap emboli E,
i.e., pieces of plaque dislodged from the walls of vessel V by
balloon 46.
[0076] With respect to FIG. 5D, upon completion of the angioplasty
procedure using angioplasty balloon catheter 44, guide wire 22 is
pulled proximally to cause the sides of support hoop 24 to collapse
together to close the mouth of sac 28 (see FIG. 3). Additional
proximal retraction of guide wire 22 causes support hoop 24 and sac
28 to enter at least partially within the guide wire lumen of
angioplasty catheter 44. As depicted in FIG. 5D, only a portion of
support hoop 24, near articulation region 26, and a distal portion
of sac 28 extend out of the guide wire lumen of angioplasty
catheter 44. Alternatively, vascular device 20 may be fully
retracted within the guide wire lumen. Angioplasty catheter 44 then
is withdrawn with vascular device 20 and any trapped emboli E.
[0077] Advantageously, the compliant design of vascular device 20
permits the device to be contracted to its delivery state within
the guide wire lumen of conventional previously known
interventional devices. Accordingly, unlike previously known
vascular devices, which require removal of the interventional
device followed by re-insertion of a specially designed catheter to
retrieve the vascular device, the system of the present invention
reduces the time, effort and trauma of this additional step.
Instead, the vascular device may be readily closed and retrieved
upon completion of the interventional procedure.
[0078] Vascular device 20 alternatively may be used in performing
thrombectomy/embolectomy. In this case, the vascular device is
deployed in a vessel at a location distal to a lesion, in the
manner depicted in FIGS. 5A and 5B. Once support hoop 24 is
deployed into contact with the vessel wall, vascular device 20 may
be retracted proximally to scrape along the wall of the vessel, and
excise thrombus so that it is captured in sac 28. Delivery sheath
44 may then be re-inserted into the vessel along guide wire 22, and
vascular device 20 is retracted and removed from the vessel.
Additional thrombectomy embodiments are described hereinbelow with
respect to FIGS. 18-20.
[0079] As discussed hereinabove, sac 28 is porous so that blood
cells may pass through while emboli E are captured. As seen in FIG.
5B, if the sum of the area of all these pores A.sub.1 is less than
the internal cross-sectional area A.sub.2 of vessel V, a pressure
drop is expected across the vascular device. This may lead to
hemolysis and insufficient downstream flow. If A.sub.1 is greater
than or equal to A.sub.2, the pressure drop is expected to
decrease. Proper selection of pore diameter (in the range of 20-400
microns) and pore density ensures that A.sub.1 is greater than or
equal to A.sub.2.
[0080] Selection of a larger pore diameter within the provided
range may also reduce the pressure drop by decreasing drag as blood
passes through sac 28. Drag may further be decreased by providing
elliptical pores through the sac that project round relative to
bloodflow when sac 28 is deployed. Furthermore, the porosity of sac
28 may be specified such that, if distal pores become occluded with
thrombus, emboli, etc., proximal pores remain open to ensure
continuous blood flow. It should also be noted that flow through
vessel V is substantially unaffected by placement of sac 28 and
hoop 24 in the flow path.
[0081] Referring now to FIG. 6, an alternative embodiment of the
vascular device of the present invention, again illustratively a
vascular filter, is described. Vascular device 50 comprises guide
wire 51 and support hoops 52 and 53 connected to blood permeable
sac 54. As discussed hereinabove, vascular device 50 includes
articulation regions 55 and 56 formed at the intersection of
opposing curved regions 57 and 58 of support hoops 52 and 53. Sac
54 preferably also is connected to guide wire 51 along its entire
length, thereby providing more controlled deployment and removal of
vascular device 50. Support hoop 53 serves to stabilize and deploy
the distal portion of sac 54. In addition, affixing sac 54 to guide
wire 51 may provide a more compact arrangement within a delivery
sheath, and prevent bunching of the sac material.
[0082] In FIGS. 7A and 7B, a further alternative embodiment of the
vascular device of the present invention is described. Vascular
device 60, shown in the deployed state, comprises guide wire 61
having multi-turn helical support hoop 63 connected at weld point
62. Blood permeable sac 64 is affixed to the distal-most portion of
support hoop 63. Support hoop 63 includes one or more side turns 65
that terminate in curved regions 66, as described hereinabove.
Curved regions 66 in turn are joined together by articulation
region 67. Preferably, side turns 65 are coupled to one another and
to the distal region of guide wire 61, e.g., by a weld bead, at
point 68.
[0083] In accordance with this aspect of the present invention,
vascular device 60 may be contracted to small profile delivery
state. When deployed from a delivery catheter, such as delivery
sheath 40 of FIG. 5A, side turns 65 expand into contact with the
walls of the vessel proximal to the location at which curved
regions 66 contact the vessel wall. Side turns 65 serve to
stabilize the support hoop 63 and sac 64 when vascular device 60 is
deployed within a blood vessel. In addition, side turns 64 are
expected to assist in orienting the axis of support hoop 63 and sac
64 in alignment with the longitudinal axis of vessel V.
Accordingly, support hoop 63 is expected to reduce the risk of
tilting of the vascular device within the vessel, and thus enhance
the safety and reliability of the device.
[0084] Referring now to FIGS. 5A-8E, several embodiments of a
delivery sheath suitable for use with the vascular device of the
present invention are described. Each of these embodiments are
designed to permit the physician to first pass a guide wire across
a lesion before passing the vascular device of the present
invention across the lesion. Thus, the risk of generating emboli,
during the step of positioning the vascular device of the present
invention distal to a lesion, is expected to be reduced.
[0085] In particular, in FIG. 8A, vascular device 70 of the present
invention comprises guide wire 71, support hoop 72 and blood
permeable sac 73 folded in a contracted delivery state within lumen
74 of delivery sheath 75. Vascular device 70 is similar in design
to vascular device 20 of FIG. 2A, except that device 70 includes
nose cone 76 affixed to distal region 77 of guide wire 71. Delivery
sheath 75 includes hemostatic fitting 78 at its proximal end and
guide wire lumen 79.
[0086] In accordance with the methods of the present invention,
vascular device 70 and guide wire 80 are used as follows. First,
unencumbered guide wire 80 is advanced through a vessel until
distal region 81 of the guide wire crosses a lesion. The proximal
end of guide wire 80 then is inserted into the distal end of guide
wire lumen 79 of delivery sheath 75 using previously known "over
the wire" techniques.
[0087] Delivery sheath 75 then is advanced over guide wire 80,
which is held stationary, until nose cone 76 and a distal portion
of the delivery sheath cross the lesion. Once support hoop 72 and
sac 73 of vascular device 70 are positioned distal to the lesion,
guide wire 80 is withdrawn from the vessel and delivery sheath 75
is retracted proximally, thereby deploying vascular device 70 to
its deployed state. As will of course be understood, nose cone 76
remains in the vessel, distal to sac 73, during deployment of the
vascular device. Upon completion of use of vascular device 70,
delivery sheath 75 may once again be advanced along guide wire 71
and the support hoop and sac retracted within lumen 74 of delivery
sheath 75. Alternatively, an interventional device may be advanced
over guide wire 71 to perform a medical procedure, and the vascular
device may be retrieved within a guide wire lumen of the
interventional device, as discussed hereinabove with respect to
FIG. 5.
[0088] Vascular device 90 of FIG. 8B is similar in construction to
that of FIG. 8A, and includes guide wire 91, support hoop 92, blood
permeable sac 93 and nose cone 94. Delivery sheath 95 includes
lumen 96 housing device 90, guide wire lumen 97, and hemostatic
fitting 98. Guide wire lumen 97 opens through skive 99 in lateral
wall 100 of delivery sheath 95. Guide wire 101 therefore may be
used in accordance with well-known "rapid exchange" techniques,
wherein the length of unencumbered guide wire 101 may be
significantly shorter than in the case of the "over the wire"
arrangement depicted in FIG. 8B. Operation of delivery sheath 95
and vascular device 90 is similar to that described hereinabove
with respect to FIG. 8A, except that the proximal end of
unencumbered guide wire 101 is passed through the distal end of
lumen 97 and passes out through skive 99.
[0089] In FIG. 8C, delivery sheath 105 includes lumen 106 that
opens through the lateral wall via skive 107, and guide wire lumen
108 that opens through the lateral wall via skive 109. Accordingly,
as will be apparent to one of ordinary skill, both vascular device
110 and guide wire 112 may be used as described hereinabove with
respect to FIG. 8A and further in accordance with "rapid exchange"
techniques.
[0090] Vascular device 113 of FIG. 8D is similar in construction to
those described hereinabove. Delivery sheath 114 includes lumen
115, guide tube 116, and hemostatic fitting 117. Lumen 115 houses
device 113 during delivery and retrieval. Guide tube 116 comprises
guide wire lumen 118, which is configured to receive unencumbered
guide wire 119. In operation, the proximal end of guide wire 119 is
passed through guide wire lumen 118 of guide tube 116. Thus, guide
wire 119 may be used in accordance with "rapid exchange" techniques
described with respect to FIG. 8B and with "over the wire"
techniques described with respect to FIG. 5A.
[0091] Vascular device 120 of FIG. 5E is also similar to those
described hereinabove. Delivery sheath 121 includes lumen 122 and
hemostatic fitting 123. Lumen 122 houses device 120. Guide wire 124
is coupled to and terminates at the proximal end of delivery sheath
121. Thus, distal end 126 of guide wire 125 of vascular device 120
is first to cross the lesion. Then, nose cone 127, attached to
guide wire 125, and a distal portion of delivery sheath 121 cross
the lesion. Guide wire 124 and attached delivery sheath 121 are
retracted proximally, thereby deploying vascular device 120 to its
deployed state. Device 120 may then be retrieved within sheath 121
or within an interventional device, as discussed hereinabove.
[0092] Referring now to FIG. 9, a previously known balloon catheter
is described. Catheter 130 is constructed of materials typically
used in catheters, such as polyethylene or polyurethane, and
includes compliant balloon 131 disposed in distal region 132.
Compliant balloon, which may be formed of nylon or latex, is
inflated using inflation port 133 at proximal end 134 of the
catheter. Catheter 135 also includes hemostatic port 136 and an
interior lumen through which a delivery sheath may be advanced to
pass out of an opening in distal end 137.
[0093] With respect to FIGS. 10A-10C, a method of using catheter
130 of FIG. 9 in conjunction with the vascular device of the
present invention is described. In accordance with this aspect of
the present invention, antegrade blood flow through a vessel is
occluded while a vascular device constructed in accordance with the
present invention is advanced across a lesion. Once the vascular
device, illustratively a vascular filter, is deployed, the balloon
is deflated, thereby permitting antegrade flow to be established.
Importantly, because flow through the vessel is stopped prior to
deployment of the vascular device, few or no emboli are expected to
bypass the filter.
[0094] More particularly, with respect to FIG. 10A, catheter 130 is
disposed in vessel V at a location proximal to lesion L, with the
vascular device of the present invention disposed in its contracted
delivery state in delivery sheath 138. In FIG. 10B, balloon 131 is
inflated via inflation port 133 to engage the interior wall of
vessel V, thereby arresting antegrade flow in the vessel.
[0095] As shown in FIG. 10C, delivery sheath 130 then is advanced
across lesion L so that the support hoop and sac of the vascular
device will be disposed distal to lesion L when deployed. During
this step, delivery sheath 138 may generate emboli E as it passes
across the lesion. However, because antegrade flow in the vessel is
stopped, the emboli will not travel distally in the vessel.
[0096] With respect to FIG. 10D, once vascular device 140 is
deployed, so that support hoop 141 and sac 142 span vessel V,
balloon 131 is deflated. This, in turn, causes antegrade flow to
become re-established in vessel V, urging emboli E into sac 142.
Catheter 130 then may be withdrawn, and additional treatment
devices advanced along guide wire 143 of vascular device 140.
Removal of vascular device 140 may be by any of the methods
described hereinabove with respect to FIG. 5D.
[0097] Referring now to FIGS. 11A-11C, still further alternative
embodiments of vascular devices constructed in accordance with the
present invention are described. Each of the devices of FIGS.
11A-11C, which are shown in the deployed state, includes two or
more support hoops to support the blood permeable sac. Each of
those support hoops in turn includes an articulation region that
permits the sides of the support hoops to collapse inwards to each
other as described hereinabove with respect to FIGS. 3 and 4.
[0098] Specifically, in FIG. 11A vascular device 150,
illustratively an embolic filter, comprises guide wire 151, support
hoops 152 and 153 having articulation regions 154 and 155,
respectively, and blood permeable sac 156 affixed to support hoops
152 and 153. Sac 156 is coupled to support hoops 152 and 153 so
that the support hoops form an opening for the sac. Support hoops
152 and 153 preferably are connected to guide wire 151 near its
distal end.
[0099] Sac 156 is also attached to the distal end of guide wire 151
at point 157. Sac 156 preferably is constructed of a thin, flexible
biocompatible material, as for the embodiments described
hereinabove, and includes openings or pores 158 that permit blood
cells to pass through the sac substantially unhindered, while
capturing any larger material that may be released during a
procedure such as angioplasty or stent placement. Pore sizes are
selected as described hereinabove with respect to FIG. 2A.
[0100] Support hoops 152 and 153 comprise hoops having circular or
rectangular cross-sections that are formed of a super-elastic
material, such as a nickel-titanium alloy ("nitinol"). During
deployment and retrieval of vascular device 150, support hoops 152
and 153 fold in half and collapse to fit within a small diameter
delivery sheath. When the delivery sheath is retracted, support
hoops 152 and 153 resume their pre-formed shape and deploy the
perimeter of sac 156 into contact with the vessel walls. Support
hoops 152 and 153 preferably comprise a nitinol wire, but also may
be formed from a multistrand nitinol cable, or other super-elastic
material.
[0101] In accordance with the principles of the present invention,
support hoops 152 and 153 are affixed to guide wire 151 at ring 159
and include reduced-thickness articulation regions 154 and 155,
constructed as described hereinabove. More particularly, support
hoops 152 and 153 are pre-formed to form structures having curved
regions 160 and 161, respectively, so that articulation regions 154
and 155 are disposed in a portion of the support hoop that is
approximately concentric with a vessel wall when vascular device
150 is deployed. Articulation regions 154 and 155 and curved
regions 160 and 161 thus enable support hoops 152 and 153 to fold
with a pre-determined shape when vascular device 150 is collapsed
to a contracted state for delivery or retrieval.
[0102] In a preferred embodiment of vascular device 150 of the
present invention, vascular device 150 easily fits within a
delivery sheath having an inner diameter of 0.0331'', and more
preferably, may be used with a delivery sheath having an inner
diameter as small as 0.026''. The deployed diameter of vascular
device 150 preferably is approximately 7 mm.
[0103] Compared to vascular device 20 of FIGS. 2-4, vascular device
150 of FIG. 11A employs two support hoops instead of one and
provides central location of guide wire 151 and attachment of blood
permeable sac 156 to the distal end of the guide wire. These
differences may provide more controlled deployment and removal of
vascular device 150. In addition, affixing sac 156 to guide wire
151 may provide a more compact arrangement within a delivery
sheath, and prevent bunching of the sac material.
[0104] Referring now to FIG. 1l B, another alternative embodiment
of the vascular device of the present invention, again
illustratively a vascular filter, is described. Vascular device 170
is similar in construction to vascular device 150, except that
vascular device 170 employs three support hoops instead of two.
Device 170 comprises guide wire 151 and support hoops 171, 172 and
173 connected to blood permeable sac 156.
[0105] As discussed hereinabove, vascular device 170 includes
articulation regions 174, 175 and 176 formed at the intersection of
opposing curved regions 178, 179 and 180 of support hoops 171, 172
and 173. Support hoops 171, 172 and 173 preferably are connected to
the distal end of guide wire 151 at ring 177. Sac 156 preferably
also is connected to guide wire 151 at point 157. Vascular device
170 is expected to provide similar advantages to those contemplated
for vascular device 150.
[0106] With reference to FIG. 11C, yet another alternative
embodiment of the vascular device of the present invention, again
illustratively a vascular filter, is described. Vascular device 190
is similar in construction to vascular devices 150 and 170, except
that vascular device 190 employs four articulated support hoops.
Device 190 comprises guide wire 151 and support hoops 191, 192, 193
and 194 connected to blood permeable sac 156, with articulation
regions 195, 196, 197 and 198 formed at the intersection of
opposing curved regions 200, 201, 202 and 203 of the respective
support hoops 191-194. Support hoops 191-194 are preferably
connected to the distal end of guide wire 151 at ring 199.
[0107] Alternative embodiments of vascular devices of the present
invention have been described with one to four support hoops. As
will be apparent to one of ordinary skill in the art of
interventional device design, any number of support hoops may be
used with minor modifications to the designs described
hereinabove.
[0108] Referring now to FIGS. 12-15, further alternative
embodiments of the vascular device of the present invention are
described. In FIG. 12, vascular device 250, illustratively an
embolic filter, comprises guide wire 252, support hoops 253 and 254
having articulation regions 255 and 256, respectively, and blood
permeable sac 258 affixed to support hoops 253 and 254. Sac 258 is
coupled to support hoop 253 at its proximal end so that the support
hoop forms an opening for the sac. Sac 258 is coupled to support
hoop 254 at its distal end to prevent emboli from spilling from sac
258 during retrieval. Support hoops 253 and 254 preferably are
connected to guide wire 252 near distal end 259 of the guide wire.
Sac 258 has openings or pores 260 that permit red blood cells to
easily pass through the sac.
[0109] During deployment and retrieval of vascular device 250,
support hoops 253 and 254 expand and collapse as discussed
hereinabove with respect to support hoop 24 of FIG. 2. Support
hoops 253 and 254 are attached to guide wire 252 at attachment
points 261 and 262, respectively, and further comprise curved
regions 263 and 264, respectively. Support hoops 253 and 254 may
include radiopaque features, such as gold or platinum bands 265,
spaced at intervals around the circumference of the hoops.
[0110] Applicant expects that vascular device 250 may further
reduce the risk that captured emboli could spill during retrieval,
and also may provide a better seal against the artery.
[0111] With reference to FIG. 13, an alternative embodiment of
vascular device 250 that prevents bunching is disclosed that may
provide even further benefits. Vascular device 270 comprises guide
wire 272 on which proximal support hoop 273 and distal support hoop
274 are disposed. The proximal and distal portions of blood
permeable sac 275 are affixed to support hoops 273 and 274,
respectively. Proximal support hoop 273 is attached to distal end
271 of guide wire 272 at attachment point 276 and includes
articulation region 277 and curved regions 278. Likewise, distal
support hoop 274 is attached to guide wire 272 at attachment point
279 and includes articulation region 280 and curved regions 281.
Sac 275 includes blood permeable pores 282. Hoops 273 and 274 may
include radiopaque features, such as gold or platinum bands 283,
spaced at intervals around the circumference of the hoops.
[0112] Proximal support hoop 273 is significantly larger in
circumference than distal hoop 274. Proximal hoop 273 seals against
the artery walls and defines the diameter of the mouth of sac 275.
Smaller distal hoop 274 prevents emboli from spilling from sac 275
when retrieving device 270. It also allows the diameter of sac 275
to decrease along its length. This taper in sac 275 is expected to
reduce the risk that sac 275 will bunch when the sac is retrieved.
Sac 275 may further by attached to guide wire 272.
[0113] Applicant has determined that where multiple support hoops
are employed, as in the embodiments of FIGS. 12 and 13, twisting of
the guide wire during deployment may prevent the sac of the
vascular device from properly sealing against the vessel wall. For
example, if guide wire 252 in the embodiment of FIG. 12 is rotated
after distal hoop 254 has been deployed, but before proximal hoop
253 has been deployed, proximal hoop 253 may deploy at an angle
with respect to distal hoop 254. This, in turn, may constrict, or
all together close, the opening of sac 258, thereby rendering the
vascular device ineffective.
[0114] FIG. 14 discloses a vascular device in accordance with the
present invention that overcomes problems associated with twisting
of the guide wire during deployment. Vascular device 290 comprises
guide wire 292 with distal end 293, and support hoops 294 and 295.
Support hoops 294 and 295 further comprise articulation regions 296
and 297, respectively, and curved regions 298 and 299,
respectively. The proximal and distal portions of blood permeable
sac 300 are attached to support hoops 294 and 295, respectively.
Sac 300 includes pores 301. Support hoops 294 and 295 are attached
to sheath 302 at attachment points 303 and 304, respectively.
Sheath 302 preferably comprises a flexible, 0.001'' thick tube made
of a biocompatible material, such as polyamide or
polytetraethylene. Guide wire 292 passes through the lumen of
sheath 302. Sheath 302 is able to rotate with respect to guide wire
292 but is translationally restrained by stops 305 and 306, for
example, solder beads.
[0115] By attaching support hoops 294 and 295 to sheath 302,
rotational problems are mitigated. Sheath 302 only transmits
translational motion of guide wire 292 to support hoops 294 and
295. Thus, twisting moments applied to wire 292 will not affect the
performance of vascular device 290. Sac 300 may also be attached to
sheath 302.
[0116] With reference to FIG. 15, a further alternative embodiment
of the vascular device of the present invention is disclosed that
also prevents bunching. Vascular device 310 comprises guide wire
312 on which support hoop 313 is disposed. Tapered blood permeable
sac 314 is affixed to support hoop 313. Hoop 313 is attached to
distal end 311 of guide wire 312 at attachment point 315 and
includes articulation region 316 and curved regions 317. Tapered
sac 314 includes blood permeable pores 318. Hoop 313 may include
radiopaque features, such as gold or platinum bands 319, spaced at
intervals around the circumference of the hoop.
[0117] As with vascular device 270 of FIG. 13, the diameter of
tapered sac 314 decreases along its length to reduce the risk of
bunching when the sac is retrieved. Tapering also reduces the
amount of material that must fit within the lumen of a delivery
sheath, and thereby allows a delivery sheath of smaller profile to
be used. Furthermore, tapering the blood permeable sac reduces the
risk that the sac will snag on a stent during retrieval.
[0118] Because vascular device 310 lacks the distal support hoop of
the embodiments of FIGS. 12 and 13, there is a reduced risk of
problems associated with twisting. In a preferred embodiment, the
diameter at the distal end of tapered sac 314 is less than the
internal diameter of the retrieval sheath with which the apparatus
is used. Tapered sac 314 may optionally be attached to guide wire
312, for example, to further mitigate bunching.
[0119] Referring now to FIG. 16, a support hoop including a
radiopaque feature is disclosed. Support hoop 320, illustratively
shown in the deployed state, comprises articulation region 321,
curved regions 322, attachment point 323, and wound radiopaque wire
324. In the preferred embodiment, wire 324 is platinum and is
either round or a strip approximately 0.001'' in diameter. Wire 324
is wrapped around hoop 320 all along its circumference.
[0120] One method of making a vascular device radiopaque is to
electroplate platinum or gold onto the device. However,
electroplating can be complex and expensive, and may cause
manufacturing difficulties. Because the hoop must change shape
during deployment and retrieval, increased thickness or flaking of
plated gold are undesirable characteristics and may promote failure
of the support hoop. By wrapping wire 324, hoop 320 maintains its
strength and flexibility. Radiopaque wire 324 may be used in
conjunction with any of the vascular devices discussed herein.
Radiopaque wire 324 may further be used with a wide variety of
other vascular filter devices, as are known in the art.
[0121] Referring now to FIGS. 17A-17C, another alternative
embodiment of the vascular device of the present invention is
described. As illustrated in FIG. 17A, vascular device 330
comprises guide wire 332 with distal region 333, wishbone sup port
hoop 335, and blood permeable sac 336. Wishbone hoop 335 comprises
spines 337 and 338 separated by a gap that serves as articulation
region 339. Articulation region 339 is shown in greater detail in
FIG. 17B, which corresponds to the area circled in FIG. 17A taken
along section line B-B. Blood permeable sac 336 is wrapped around
and attached to itself all along its perimeter, creating hem bond
340 and lumen 341. Sac 336 includes pores 347. Lumen 341 is
configured to receive spines 337 and 338 and bridge the gap between
them. FIG. 17C is a sectional view taken along line C-C of FIG.
17A, showing hem bond 340 and lumen 341 with spine 338 passing
there through.
[0122] Referring again to FIG. 17A, wishbone support hoop 335 is
attached to sheath 343 at attachment point 344. Sheath 343 is
similar to sheath 302 of the embodiment of FIG. 14, and preferably
comprises a flexible, 0.001'' thick tube made of a biocompatible
material, such as polyamide or polytetraethylene. Distal end 333 of
guide wire 332 passes through the lumen of sheath 343. Sheath 343
may rotate with respect to guide wire 332 but is translationally
restrained by stops 345 and 346, for example, solder beads. Sheath
343 mitigates rotational problems by only transmitting
translational motion of guide wire 332 to wishbone hoop 335.
Twisting moments applied to wire 332 do not affect the performance
of vascular device 330.
[0123] The wishbone design of support hoop 335 advantageously
enables a wider variety of materials to be used to fabricate the
support hoop. Articulation region 339 allows vascular device 330 to
deploy and contract in a manner similar to that described above for
alternative embodiments. Deployment and retraction of wishbone hoop
335 induces minimal deformation of spines 337 and 338, thereby
permitting use of materials such as spring steel. As will of course
be apparent, the support hoop of the embodiment of FIGS. 17A-17C
may advantageously be incorporated in any of the foregoing
embodiments.
[0124] Referring now to FIGS. 18A and 18B, an integrated vascular
device suitable for thrombectomy is described. The integrated
device comprises a thrombectomy element and a vascular filter. In a
preferred embodiment, the thrombectomy element is similar in
construction to vascular filter 20 described above and is connected
to the guide wire proximal of the vascular filter. Alternatively,
the thrombectomy element may be disposed on a separate catheter.
The thrombectomy element may be retracted independently of the
vascular filter.
[0125] In FIG. 18, integrated vascular device 350 comprises guide
wire 351, thrombectomy element 352 including support hoop 353 and
blood permeable sac 354, and vascular filter element 355 including
support hoop 356 and blood permeable sac 357. Filter hoop 356 is
attached to guide wire 351 while thrombectomy hoop 353 is attached
to ring 358. Ring 358 is attached to pull wire 359 and has a bore
through which guide wire 351 passes. Ring 358 therefore acts as a
linear bearing and allows thrombectomy hoop 353 to be moved by pull
wire 359 independently of guide wire 351. Alternatively,
thrombectomy element 352 may omit sac 354 and simply comprise a
wire hoop; in this case severed thrombus is captured by vascular
filter 355.
[0126] In FIG. 18A, support hoops 353 and 356 and blood permeable
sacs 354 and 356 are contracted to a delivery state within lumen
360 of delivery sheath 361. Delivery sheath 361 includes nose cone
362 affixed to distal region 363 of guide wire 351. In FIG. 18B,
integrated vascular device 350 is shown deployed in a vessel. As
illustrated in FIG. 18B, vascular filter 355 expands to engage the
perimeter of the vessel and prevent thrombus from bypassing the
blood permeable sac, while thrombectomy element 352 engages the
vessel wall proximal of vascular filter 355. As described
hereinbelow, proximal movement of thrombectomy device 352 scrapes
thrombus from the wall of the vessel when pull wire 359 pulls ring
358 and support hoop 353 proximally.
[0127] Referring now to FIGS. 19A-19E, an illustrative method of
using the integrated vascular device of the present invention for
thrombectomy is described. In FIG. 19A, guide wire 351 is
manipulated into position proximal to thrombus T within vessel V
using well-known percutaneous techniques. Vascular device 350 of
FIGS. 18A and 18B is disposed in its contracted delivery state
within the distal end of delivery sheath 361 and the delivery
sheath is advanced through the vessel using distal end 363 of guide
wire 351. The sides of support hoops 353 and 356 are folded
together and become elongated when drawn within delivery sheath
361, as described with respect to vascular device 20 of FIGS.
2-4.
[0128] With respect to FIG. 19B, once delivery sheath 361 is
disposed at the desired location proximal to thrombus T within a
patient's vessel V, such as a coronary artery or carotid artery,
based on the position of, for example, radiopaque bands under a
fluoroscope, integrated vascular device 350 is advanced through
thrombus T. Distal end 363 of guide wire 351 is advanced through
the lesion, then nose cone 362 gradually increases the diameter of
the void within thrombus T so that the remainder of delivery sheath
361 can be advanced far enough that thrombectomy element 352 (still
within delivery sheath 361) is located distal to thrombus T.
[0129] With integrated vascular device 350 in position, guide wire
351 is held stationary while delivery sheath 361 is retracted
proximally, as seen in FIG. 19C. Alternatively, delivery sheath 361
may be held stationary while guide wire 351 is advanced. In either
case, when vascular device 350 is no longer confined within
delivery sheath 361, support hoops 353 and 356 expand to seal
against the walls of the vessel V and deploy blood permeable sacs
354 and 357, respectively. Blood continues to flow through vessel V
in direction A, impeded only by thrombus T.
[0130] In FIG. 19D, once vascular device 350 is deployed in vessel
V, thrombus T is removed in the following manner. Vascular filter
support hoop 353 is rigidly attached to guide wire 351, while
thrombectomy support hoop 353 is attached to pull wire 359 via ring
358. Thrombectomy element 352 then is retracted proximally to
scrape along the wall of the vessel V by motion at the proximal end
of pull wire 359. Thrombus T, located proximal to thrombectomy
element 352, is excised so that it is captured in blood permeable
sac 354 during the retraction.
[0131] With respect to FIG. 19E, once thrombus T has been captured
within sac 354, pull wire 359 is pulled proximally to cause the
sides of thrombectomy support hoop 353 to collapse together to
close the mouth of sac 354 (see FIG. 3). Additional proximal
retraction of pull wire 359 causes support hoop 353 and sac 354 to
enter within lumen 360 of delivery sheath 361, restoring normal
blood flow to vessel V. Meanwhile, vascular filter 355 is in a
position distal to thrombectomy element 352 to trap emboli E, i.e.,
pieces of plaque dislodged from either thrombus T or the walls of
vessel V by thrombectomy element 352. Once any emboli E have been
collected, filter hoop 356 and sac 357 are retracted into delivery
sheath 361 by motion at the proximal end of guide wire 351, in a
manner similar to the retraction of hoop 353 and sac 354. Once
guide wire 351 has been fully retracted, and nose cone 362 at the
distal end 363 of guide wire 351 is again in contact with delivery
sheath 361, the delivery sheath is withdrawn with integrated
vascular device 350, the trapped thrombus T, and any trapped emboli
E.
[0132] As with previous embodiments, the compliant design of
integrated vascular device 350 permits the device to be contracted
to its delivery state within the guide wire lumen of conventional
previously known interventional devices, thereby reducing time,
effort, and trauma. The vascular device may be readily closed and
retrieved upon completion of the interventional procedure.
[0133] Referring now to FIGS. 20A and 20B, an alternative
embodiment of the integrated vascular device is described.
Integrated vascular device 370 comprises guide wire 371,
thrombectomy element 372, and vascular filter 373 having support
hoop 374 and blood permeable sac 375. Filter hoop 374 is attached
to guide wire 371, while thrombectomy element 372 is disposed to
slide along guide wire 371. Alternatively, thrombectomy element 372
may be disposed on a separate catheter element that extends either
through lumen 377 of delivery sheath 378 or is separately disposed
proximal to vascular filter 373. FIG. 20A shows thrombectomy
element 372 and vascular filter 373 contracted in a delivery state
within lumen 377 of delivery sheath 378. Delivery sheath 378
includes nose cone 379 affixed to distal region 380 of guide wire
371. In FIG. 20B, integrated vascular device 370 is shown in the
deployed state.
[0134] Thrombectomy element 372 may comprise any of a family of
known thrombectomy, atherectomy, or, alternatively, drug delivery
devices suitable for use in conjunction with vascular filter 373.
Thrombectomy element 372 may, for example, comprise any of: a
rotary ablation device, such as described in U.S. Pat. Nos.
4,867,156 to Stack et al., 4,990,134 to Auth, and 5,314,407 to Auth
et al.; an atherectomy technology, such as described in U.S. Pat.
Nos. 5,181,920 to Mueller et al., and 5,074,841 to Ademovic et al.;
or a balloon embolectomy technology, such as described in U.S. Pat.
Nos. 3,923,065 to Nozick et al., 5,769,871 to Mers Kelly et al.,
5,192,290 to Hilal, 5,112,347 to Taheri, and 4,030,503 to Clark
III. All of the foregoing patents are incorporated herein by
reference. Thrombectomy element 372 may alternatively comprise a
wire loop or ring, such as described for the embodiment of FIGS.
18A and 18B, a laser ablation device, a chemical flushing system,
etc.
[0135] Referring now to FIGS. 21A and 211B, a delivery system
configured for use with embodiments of the present invention is
described. The delivery system facilitates deployment and retrieval
of the embodiments by integrating the functions of a torquer, a
Touhy Borst adapter, and a pusher into a single device. In FIG. 21,
the delivery system is illustratively used in conjunction with
vascular device 20 of FIGS. 2-5. In FIG. 21A, vascular device 20 is
in the retracted delivery configuration, while in FIG. 21B vascular
device 20 is in the expanded deployed configuration. Delivery
system 450 comprises proximal screw cap 452, collet 456, handle
460, rod 464, central screw cap 468, lumen flushing section 472,
distal hub 479, and nose piece 486.
[0136] Proximal screw cap 452 includes bore 453 with female screw
thread 454 and guide wire lumen 455. Bore 453 extends proximally
from the distal face of cap 452. Guide wire lumen 455 extends from
the proximal end of bore 453 to the proximal end of cap 452.
[0137] Handle 460 comprises proximal male screw thread 461
configured to engage female screw thread 454 of cap 452, and lumen
462 configured to receive collet 456 in its proximal end and rod
464 in its distal end. Lumen 462 has a reduced diameter at the
distal end of handle 460 that captures a step on the proximal end
of rod 464. Thus, while collet 456 is removable received within
lumen 462, rod 464 may translate and rotate within, but may not be
removed from, lumen 462. Guide wire 422 freely passes through
collet 456 when screw cap 452 is not securely fastened to handle
460. When cap 452 is securely fastened to handle 460, it causes
collet 456 to elastically deform, decreasing the diameter of the
lumen extending through the collet, and frictionally locking guide
wire 422 into rigid attachment with collet 456. Guide wire 422 is
thereby rigidly connected to handle 460.
[0138] Rod 464 further comprises guide wire lumen 465 extending
therethrough. Rod 464 has its distal end rigidly and permanently
affixed to central screw cap 468. Cap 468 comprises female screw
thread 469 and lumen 470. Lumen 470 includes a proximal
reduced-diameter step that captures rod 464 within the proximal end
of cap 468, and a distal portion that receives lumen flushing or
fluid port section 472.
[0139] Section 472 comprises male screw thread 473, side port 474,
bore 475, guide wire lumen 476, and fluid lumen 477. Male screw
thread 473 is configured to engage female thread 469 of cap 468.
Section 472 includes a flange disposed just distal of thread 473
that is captured within lumen 470 of cap 468. Thus, cap 468 may be
tightened onto and loosened from, but not removed from, section
472.
[0140] Rod 464 is received within bore 475 of section 472. Guide
wire 22 passes between bore 475 and fluid lumen 477 within guide
wire lumen 476. Fluid lumen 477 connects side port 474 to the guide
wire lumen of delivery sheath 40. O-rings 478 provide a fluid seal
at the distal end of lumen 477.
[0141] Distal hub 479 connects section 472 to nose piece 486. Hub
479 comprises bore 483, female screw thread 484, and annulus 485
containing tapered projection 481. Bore 483 includes flange 482
that rotatably receives section 472 in its proximal end. Nose piece
486 comprises male screw thread 487, tapered bore 488, and delivery
sheath lumen 489. Male screw thread 487 is configured to engage
female thread 484 in annulus 485 of hub 479. Tapered bore 488
allows tapered projection 481 of hub 479 to extend within nose
piece 486 and permit delivery sheath 40 from delivery sheath lumen
489 to extend therethrough. O-rings 478 are disposed between the
hub 479 and nose piece 486 and between hub 479 and section 472.
[0142] Delivery system 450 advantageously may be implemented in a
variety of ways. For example, the delivery system may be offered
with a delivery catheter or sheath pre-attached. In this
embodiment, proximal screw cap 452 is loosened, and the proximal
end of guide wire 22 may be passed through the delivery catheter or
sheath, and delivery system 450, until vascular device 20 is in its
retracted state within the delivery catheter or sheath. Insertion
of the vascular device into the patient may then proceed.
Alternatively, delivery system 450 may be commercially supplied in
the configuration shown in FIG. 5A, i.e., pre-loaded with a
delivery catheter or sheath, such as sheath 40, already attached
and a vascular device, such as vascular device 20, retracted
therein. As another alternative, delivery system 450 may be offered
without either a delivery sheath or vascular device attached, or
the delivery catheter or sheath may be an interventional
instrument, such as an angioplasty, atherectomy, or stent delivery
catheter.
[0143] Referring again to FIGS. 5A-5D in conjunction with FIGS. 21A
and 21B, a method of using the delivery system of the present
invention in conjunction with a vascular filter is described. With
vascular device 20 contracted within distal end 42 of delivery
sheath 40 (FIGS. 5A and 21A), delivery sheath 40 is attached to
delivery system 450 by loosening proximal screw cap 452 and
extending the proximal end of guide wire 22 through delivery system
450, with handle 460 in its proximal-most position (FIG. 21A).
Screw cap 452 is then tightened to cause collet 456 to engage guide
wire 22 to handle 460.
[0144] Delivery sheath 40 then is advanced through a patient's
vasculature using well-known percutaneous techniques using distal
end 23 of guide wire 22. If a vessel bifurcation is to be crossed
during advancement, handle 460 may be rotated to divert the distal
end of sheath 40 into the desired branch of the bifurcation. The
rotational moment or torque applied to handle 460 is transmitted to
guide wire 22 (when screw cap 452 is tightened), which causes
distal end 23 to rotate and facilitates positioning of vascular
device 20 in the proper side of the bifurcation. As shown in FIG.
5A, advancement continues until delivery sheath 40 is disposed at a
desired location within a patient's vessel V, such as a coronary or
carotid artery, as determined, for example, by the position of
radiopaque band 43 under a fluoroscope.
[0145] With the vascular device in position, handle 460, and thus
guide wire 22, is held stationary while section 472 and attached
delivery sheath 40 are retracted proximally. Alternatively, handle
460 may be advanced while section 472 and sheath 40 are held
stationary. In either case, when vascular device 20 is no longer
confined within delivery sheath 40, support hoop 24 expands to seal
against the walls of the vessel V, as depicted in FIGS. 5B and 21B.
Blood continues to flow unimpeded through vessel V in direction
A.
[0146] Depending on the medical procedure prescribed in conjunction
with the use of vascular device 20, delivery sheath 40 may retrieve
vascular device 20 at the conclusion of the procedure, or sheath 40
may be detached from delivery system 450 and removed from the
patient. If sheath 40 is detached, guide wire 22 may be removed
from delivery system 450 so that other interventional instruments,
such as angioplasty catheters, atherectomy devices, or stent
delivery systems may be advanced along guide wire 22 to position
such devices at treatment zones located proximally of vascular
device 20. Guide wire 22 and the interventional catheter then may
be passed through and fastened to delivery system 450. For example,
as shown in FIG. 5C, angioplasty balloon catheter 44 may be
advanced along guide wire 22 to a position proximal of vascular
device 20 so that device 20 may trap emboli E, i.e., pieces of
plaque dislodged from the walls of vessel V by balloon 46.
[0147] Upon completion of the angioplasty procedure using
angioplasty balloon catheter 44, handle 460 with attached guide
wire 22 is pulled proximally to cause the sides of support hoop 24
to collapse together to close the mouth of sac 28 (FIG. 3).
Additional proximal retraction of guide wire 22 causes support hoop
24 and sac 28 to enter at least partially within the guide wire
lumen of angioplasty catheter 44. As depicted in FIG. 4D, only a
portion of support hoop 24, near articulation region 26, and a
distal portion of sac 28 extend out of the guide wire lumen of
angioplasty catheter 44. Angioplasty catheter 44 then is withdrawn
with vascular device 20 and any trapped emboli E.
[0148] It also may be beneficial during a medical procedure to
introduce or withdraw fluids from the operative site. For example,
it may be beneficial to deliver medicaments, or draw suction to
remove blood. The delivery sheath lumen also may require flushing
with saline to prevent clotting within the lumen. These and other
procedures are made possible by side port 474 of section 472,
which, as described hereinabove, is in fluid communication with the
lumen of delivery sheath 40.
[0149] In addition to applications with vascular filters, delivery
system 450 may be used as part of the thrombectomy/embolectomy
procedure described herein above, as well as in a variety of other
procedures.
[0150] Embodiments of the present invention may optionally be used
in conjunction with a specially configured retrieval sheath.
Applicant has determined that bunching of sac 28 in FIG. 5D may
occur during retraction into catheter 44, resulting in a retrieval
profile that may be difficult to navigate through a patient's
vasculature. However, additional proximal retraction of guide wire
22 in an attempt to decrease the profile of sac 28 may generate
stress loads sufficient to tear sac 28 and release captured
emboli.
[0151] With reference to FIGS. 22A-22E, a specially configured
retrieval sheath and methods of use with the vascular device of the
present invention are described. As with FIG. 5, sizes have been
exaggerated to illustrate structure. In FIG. 22A, guide wire 556 is
positioned within vessel V using well-known percutaneous
techniques. Vascular device 550 is disposed in its contracted
delivery state within distal end 554 of delivery sheath 552.
Retrieval sheath 560 and guide catheter 562 are advanced over
delivery sheath 552 to a position located just proximal of distal
end 554.
[0152] Retrieval sheath 560 includes collapsible flared end region
564, which is shown in a contracted delivery state within catheter
562 in FIG. 22A. Flared end region 564 has a deployed state,
wherein the wall flares outward to form a frustum of a cone, and a
contracted state, wherein the wall is substantially cylindrical.
Flared end region 564 preferably includes radiopaque hand 566.
[0153] With respect to FIG. 22B, once delivery sheath 552 is
disposed at a desired location within a patients vessel V, guide
wire 556 is held stationary while delivery sheath 552 is retracted
proximally. Alternatively, delivery sheath 552 may be held
stationary while guide wire 556 is advanced. In either case, when
vascular device 550 is no longer confined within delivery sheath
552, support hoop 568 and attached blood permeable sac 570, expands
to seal against the walls of the vessel V. Sac 570 further
comprises radiopaque band 572. When in the deployed state, the
curved regions of support hoop orient its articulation region
concentrically against the inside wall of the vessel. Blood
continues to flow unimpeded through vessel V in direction A.
[0154] With vascular device 550 deployed, an interventional
procedure is performed proximal of the device. For example, guide
catheter 562 may be an angioplasty balloon catheter similar to
catheter 44 of FIGS. 5C and 5D. The interventional procedure
generates emboli E proximal of device 550, which travel downstream
and are captured in sac 570.
[0155] With respect to FIG. 22C, upon completion of the
interventional procedure, guide wire 556 is pulled proximally to
cause the sides of support hoop 568 to collapse together to close
the mouth of sac 570 (see FIG. 3). Additional proximal retraction
of guide wire 556 causes support hoop 568 and sac 570 to partially
enter within distal end 554 of delivery sheath 552. If bunching of
the sac is anticipated or suspected, flared sheath 560 may be
advanced distally to expand end region 564, which comprises a
suitable elastomeric material, such as latex, rubber, or a
synthetic variant thereof.
[0156] As depicted in FIG. 22D, delivery sheath 552 is retracted
proximally while retrieval sheath 560 is held stationary, until
radiopaque bands 572 and 566 are concentrically aligned, as
determined, for example, with a fluoroscope. Then, as illustrated
in FIG. 22E, sheaths 552 and 560 are simultaneously withdrawn
proximally while guide catheter 562 is held stationary. This motion
causes flared end region 564 to collapse sac 570 to its contracted
state. In so doing, flared end region 564 applies a distributed
load over the surface of sac 570, thereby decreasing the retrieval
profile of sac 570 with reduced risk of rupture of sac 570.
[0157] Vascular device 550 also may be used in performing
thrombectomy/embolectomy. In this case, vascular device 550 is
advanced in its retracted state within delivery sheath 552 to a
location distal of a lesion. Delivery sheath 552 is withdrawn
proximally, and vascular device 550 is deployed. With support hoop
568 in contact with the vessel wall, vascular device 550 may be
retracted proximally to scrape along the wall of the vessel and
excise thrombus so that it is captured in sac 570. Delivery sheath
552, as well as flared sheath 560 and guide catheter 562, then may
be reinserted into the vessel along guide wire 556, and vascular
device 550 may be retracted and removed from the vessel in the
manner described hereinabove.
[0158] With reference to FIGS. 23A and 23B, an alternative
embodiment of the specially configured retrieval sheath, and
methods of use with the vascular device of the present invention,
are described. Again, sizes have been exaggerated to illustrate
structure. In FIG. 23A, guide wire 582 has been positioned within
vessel V using well-known percutaneous techniques. Vascular device
580 has been expanded to its deployed state after delivery within
delivery sheath 584, in the manner discussed hereinabove. Support
hoop 586 seals against the walls of vessel V, and blood permeable
sac 588 is positioned to capture emboli E generated by, for
example, an upstream interventional procedure. Blood continues to
flow unimpeded through vessel V in direction A.
[0159] Delivery sheath 584 further comprises atraumatic expander
590 disposed on a distal end. Retrieval sheath 592 is advanced over
delivery sheath 584 to a position located just proximal of expander
590. Retrieval sheath 592 includes expandable end region 594, which
is shown in a contracted delivery state in FIG. 23A. Expandable end
region 594 has a deployed state, wherein the wall flares outward to
form a frustum of a cone, and a contracted state, wherein the wall
is substantially cylindrical. Expander 590 has a larger maximum
diameter than end region 594. Expandable end region 594 preferably
includes radiopaque band 596, while expander 590 preferably
includes radiopaque band 598 so that their positions relative to
one another may be accurately determined.
[0160] With respect to FIG. 23B, upon completion of the
interventional procedure, guide wire 582 is pulled proximally to
cause the sides of support hoop 586 to collapse together to close
the mouth of sac 588 (see FIG. 3). Additional proximal retraction
of guide wire 582 causes support hoop 586 and sac 588 to partially
enter within the distal end of delivery sheath 584.
[0161] If bunching of the sac is anticipated or suspected, delivery
sheath 584 may be retracted proximally while retrieval sheath 592
is held stationery to expand end region 594 of retrieval sheath 592
with expander 590. Delivery sheath 584 is retracted a sufficient
distance to protect sac 588 and its embolic contents within end
region 594. The distance may be determined by means of radiopaque
bands 596 and 598. End region 594 comprises a suitable elastomeric
material, such as latex, rubber or a synthetic variant thereof.
[0162] The profile of end region 594 in the expanded state allows
for retraction of retrieval sheath 592, as well as delivery sheath
584 and vascular device 580 disposed therein, in a manner that
mitigates dangerous interaction with the vascular wall. It also
allows vascular device 580 to be retrieved in a partially collapsed
state that reduces the risk of sac 588 tearing. As with vascular
device 550, vascular device 580 may be used in performing
thrombectomy/embolectomy.
[0163] The support hoops depicted herein illustratively are shown
as oval or heart-shaped in the deployed state, where the shape is
exaggerated for the sake of clarity. In preferred embodiments, the
support hoops are substantially round when deployed, to ensure
contact around the circumference of the support hoop and provide a
positive seal against the arterial wall.
[0164] Although preferred illustrative embodiments of the present
invention are described above, it will be evident to one skilled in
the art that various changes and modifications may be made without
departing from the invention. It is intended in the appended claims
to cover all such changes and modifications that fall within the
true spirit and scope of the invention.
* * * * *