U.S. patent application number 10/684942 was filed with the patent office on 2004-04-29 for systems and methods for vascular filter retrieval.
This patent application is currently assigned to INCEPT LLC. Invention is credited to Demond, Jackson F., Khosravi, Farhad, Krolik, Jeff A., Salahieh, Amr.
Application Number | 20040082968 10/684942 |
Document ID | / |
Family ID | 25071610 |
Filed Date | 2004-04-29 |
United States Patent
Application |
20040082968 |
Kind Code |
A1 |
Krolik, Jeff A. ; et
al. |
April 29, 2004 |
Systems and methods for vascular filter retrieval
Abstract
Apparatus and methods for retrieving a vascular filter from a
vessel are provided wherein a retrieval adapter is delivered to a
treatment site concurrently along with an interventional device to
reduce the number of steps required to remove the vascular filter.
The retrieval adapter also reduces the possibility of entangling
the vascular filter with a stent disposed within the vessel during
removal of the vascular filter. A separate retrieval catheter is
also described for use in conjunction with the retrieval
adapter.
Inventors: |
Krolik, Jeff A.; (Campbell,
CA) ; Salahieh, Amr; (Campbell, CA) ; Demond,
Jackson F.; (Santa Cruz, CA) ; Khosravi, Farhad;
(San Mateo, CA) |
Correspondence
Address: |
Glenn M. Seager
CROMPTON, SEAGER & TUFTE, LLC
Suite 800
1221 Nicollet Avenue
Minneapolis
MN
55403-2420
US
|
Assignee: |
INCEPT LLC
|
Family ID: |
25071610 |
Appl. No.: |
10/684942 |
Filed: |
October 14, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10684942 |
Oct 14, 2003 |
|
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09764732 |
Jan 16, 2001 |
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6663651 |
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Current U.S.
Class: |
606/200 |
Current CPC
Class: |
A61F 2230/0067 20130101;
A61F 2002/018 20130101; A61F 2230/008 20130101; A61F 2002/015
20130101; A61F 2230/0006 20130101; A61F 2230/0008 20130101; A61F
2/011 20200501 |
Class at
Publication: |
606/200 |
International
Class: |
A61M 029/00 |
Claims
What is claimed is:
1. Apparatus for use in conjunction with an interventional device
in retrieving a vascular filter disposed on a guidewire from a
vessel, the apparatus comprising: a tubular body having a proximal
end, a distal end and a lumen, the tubular body configured to be
disposed on a distal region of the guidewire only so that the
proximal end engages a distal end of the interventional device, the
tubular body configured to receive at least a portion of the
vascular filter within the lumen during retrieval of the vascular
filter from the vessel.
2. The apparatus of claim 1 wherein the tubular body comprises a
biocompatible material.
3. The apparatus of claim 1 wherein the tubular body comprises a
radiopaque material.
4. The apparatus of claim 3 wherein the radiopaque material
comprises a radiopaque coil embedded in the tubular body.
5. The apparatus of claim 1 wherein the proximal end is tapered to
facilitate engagement with a distal end of the interventional
device.
6. The apparatus of claim 5 wherein the tubular body is mounted on
the distal end of the interventional device.
7. The apparatus of claim 5 wherein the proximal end abuts against
the distal end of the interventional device.
8. The apparatus of claim 1 wherein the distal end of the tubular
body includes at least one slit.
9. The apparatus of claim 1 wherein the distal end of the tubular
body is perforated.
10. The apparatus of claim 1 wherein the tubular body has a length
less than about 50 mm.
11. A system for retrieving a vascular filter comprising: a
guidewire having a distal end; a vascular filter disposed on the
guidewire adjacent the distal end of the guidewire; an
interventional device having a distal end and a lumen extending
therethrough, the interventional device disposed on the guidewire
proximally of the vascular filter; and a retrieval adapter
slidingly disposed on the guidewire and interposed between the
vascular filter and the distal end of the interventional
device.
12. The system of claim 11 wherein the retrieval adapter includes a
lumen adapted to receive at least a portion of the vascular
filter.
13. The system of claim 11 wherein the retrieval adapter comprises
a biocompatible material.
14. The system of claim 11 wherein the retrieval adapter comprises
a radiopaque material.
15. The system of claim 14 wherein the radiopaque material
comprises a radiopaque coil embedded in the retrieval adapter.
16. The system of claim 11 wherein the retrieval adapter further
comprises a proximal region tapered to facilitate engagement with
the distal end of the interventional device.
17. The system of claim 16 wherein the retrieval adapter is
configured to be mounted on the distal end of the interventional
device.
18. The system of claim 11 wherein a distal end of the retrieval
adapter includes at least one slit.
19. The system of claim 11 wherein a distal end of the retrieval
adapter is perforated.
20. The system of claim 11 wherein the retrieval adapter has a
length of less than about 50 mm.
21. A system for retrieving a vascular filter comprising: a
guidewire having a distal end; a vascular filter disposed on the
guidewire adjacent the distal end of the guidewire, the vascular
filter comprising a suspension strut coupled to the guidewire, a
support hoop coupled to the suspension strut, and a blood permeable
sac coupled to the support hoop; an interventional device having a
distal end and a lumen extending therethrough, the interventional
device disposed on the guidewire proximally of the vascular filter;
and a retrieval adapter slidingly disposed on the suspension
strut.
22. The system of claim 21 wherein the retrieval adapter includes a
lumen adapted to receive at least a portion of the vascular
filter.
23. The system of claim 21 wherein the retrieval adapter comprises
a biocompatible material.
24. The system of claim 21 wherein the retrieval adapter comprises
a radiopaque material.
25. The system of claim 21 wherein a distal end of the retrieval
adapter is radially expandable.
26. The system of claim 21 further comprising a safety device that
inhibits inadvertent closing of the vascular filter.
27. A method of retrieving a vascular filter comprising: providing
a guidewire, a vascular filter, an interventional device and a
retrieval adapter; deploying the vascular filter on the guidewire
distal to a treatment site; disposing a retrieval adapter on the
guidewire in engagement with a distal end of the interventional
device; advancing the retrieval adapter and interventional device
along the guidewire to the treatment site; performing a diagnostic
or therapeutic procedure at the treatment site using the
interventional device; and upon completion of the diagnostic or
therapeutic procedure, advancing the interventional device distally
along the guidewire so that the retrieval adapter captures the
vascular filter.
28. The method of claim 27 wherein advancing the interventional
device distally along the guidewire causes the vascular filter to
be received at least partially within a lumen of the retrieval
adapter.
29. A method of retrieving a vascular filter comprising: providing
a guidewire, a vascular filter including a retrieval adapter and an
interventional device; deploying the vascular filter and retrieval
adapter on the guidewire distal to a treatment site; advancing the
interventional device along the guidewire to the treatment site;
performing a diagnostic or therapeutic procedure at the treatment
site using the interventional device; upon completion of the
diagnostic or therapeutic procedure, advancing the interventional
device distally along the guidewire so that the interventional
device abuts against the retrieval adapter; and advancing the
interventional device further distally along the guidewire so that
the interventional device causes the retrieval adapter to capture
the vascular filter.
30. The method of claim 29 wherein advancing the interventional
device distally along the guidewire causes the vascular filter to
be received at least partially within a lumen of the retrieval
adapter.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to apparatus and methods for
retrieving a vascular device, such as a filter, from within a
vessel. More particularly, the present invention provides apparatus
useful for retrieving a vascular filter used to prevent
embolization associated with diagnostic or therapeutic
interventional procedures, thrombectomy and embolectomy.
BACKGROUND OF THE INVENTION
[0002] 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.
[0003] The deployment of stents and stent-grafts to treat vascular
disease, such as aneurysms, 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.
[0004] Numerous blood filters are known that are designed to
capture material liberated from vessel walls during the treatment
of vascular disease. Such treatment procedures, such as
angioplasty, atherectomy and stenting, typically involve
transluminally inserting an interventional device to the treatment
site along a guidewire. Upon completion of the procedure, the
interventional device is removed from the patient's blood vessel,
and a retrieval mechanism, such as a sheath, is advanced along the
guidewire in order to retrieve the blood filter.
[0005] One drawback associated with using a sheath to retrieve a
filter is that the retrieval process requires two steps: (1) the
interventional device (e.g., angioplasty catheter) must be removed
and (2) the retrieval sheath must then be advanced along the
guidewire to retrieve the filter. This additional exchange adds
time to the length of the procedure, involves introduction of an
additional element (the retrieval catheter) into the patient's
vasculature, and enhances the risk of dislodging the filter and
permitting emboli to escape therefrom.
[0006] Moreover, as the retrieval sheath is advanced along the
guidewire, its distal end may become entangled with a stent
disposed within the patient's vessel. If, for example, a stent has
been deployed, the distal end of the retrieval sheath may
inadvertently engage a stent strut, preventing further advancement
of the retrieval sheath within the vessel, or even possibly causing
vessel dissection.
[0007] One disadvantage associated with attempting to retrieve a
vascular filter using the guidewire lumen of an interventional
device, such as an angioplasty catheter, is that the diameters of
such lumens are typically quite small, e.g., 0.014 inch.
Accordingly, it is not possible to retrieve previously known
vascular filters using the guidewire lumens of most interventional
devices.
[0008] In view of the foregoing, it would be desirable to provide
improved apparatus and methods that streamline retrieval of a
vascular filter.
[0009] It further would be desirable to provide improved apparatus
and methods that facilitate retrieval of a vascular filter, with
reduced risk of entangling a retrieval sheath in a deployed
stent.
SUMMARY OF THE INVENTION
[0010] In view of the foregoing, it is an object of the present
invention to provide improved apparatus and methods that streamline
retrieval of a vascular filter.
[0011] It is another object of the present invention to provide
improved apparatus and methods that facilitate retrieval of a
vascular filter, with reduced risk of entangling a retrieval sheath
in a deployed stent.
[0012] These and other objects of the present invention are
accomplished by providing a retrieval apparatus that reduces the
time and effort required to retrieve a vascular filter from a
patient's vessel.
[0013] In one preferred embodiment, the present invention includes
a retrieval adapter having a proximal end configured to be fitted
to the end of an interventional device, such as an angioplasty
catheter, and a radially expandable distal end. Upon completion of
an interventional procedure such as angioplasty, the balloon of the
angioplasty catheter is deflated and the angioplasty catheter then
is advanced along the guidewire until the adapter captures the
vascular filter.
[0014] Alternatively, upon completion of the interventional
procedure, the guidewire and attached vascular filter may be
withdrawn proximally until the vascular filter engages and is
caused to be collapsed by the adapter. Once the vascular filter is
collapsed, the vascular filter is partially withdrawn within the
adapter, and the vascular filter, adapter, interventional device
and guidewire are all removed from the vessel. This streamlined
procedure provides a substantial improvement over previously known
systems, which typically require exchanging the interventional
device for a retrieval sheath before retrieving the vascular filter
from the treatment site.
[0015] In another embodiment, the retrieval adapter of the present
invention may be loaded directly onto the guidewire having the
vascular filter so that the adapter is delivered to a treatment
site concurrently with the filter. After completion of a diagnostic
or therapeutic procedure involving an interventional device, such
as an angioplasty catheter, the interventional device is advanced
along the guidewire. As the distal end of the interventional device
moves distally, it abuts against the adapter and urges the adapter
into contact with the filter, thereby causing the adapter to
collapse and capture the vascular filter. Alternatively, as for the
previous embodiment, the interventional device may be held
stationary and the vascular filter and adapter retracted
proximally.
[0016] In yet another embodiment, the present invention includes a
retrieval catheter having proximal and distal ends. The proximal
end of the catheter is loaded onto the distal end of an
interventional device, and that assemblage then is loaded onto the
guidewire having the vascular filter. After completion of a
diagnostic or therapeutic procedure, such as stent deployment, the
retrieval catheter is advanced over the working element of the
interventional device (e.g., the deflated balloon) and the vascular
filter. Alternatively, the retrieval catheter may be held
stationary and the vascular filter and guidewire retracted
proximally to collapse and capture the filter in the retrieval
sheath.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] 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:
[0018] FIG. 1 is a perspective view of a first previously known
vascular filter suitable for use with the apparatus of the present
invention;
[0019] FIG. 2 is a perspective view of another previously known
vascular filter suitable for use with the apparatus of the present
invention;
[0020] FIG. 3 is a side view of yet another vascular filter
suitable for use with the apparatus of the present invention;
[0021] FIGS. 4A and 4B are, respectively, side sectional and side
views of apparatus of the present invention;
[0022] FIGS. 5A and 5B are side sectional views illustrating the
use of the apparatus of FIG. 4 to retrieve the vascular filter of
FIG. 3;
[0023] FIG. 6 is a side view of a retrieval catheter constructed in
accordance with the principles of the present invention;
[0024] FIGS. 7A-7C are side sectional views depicting a method of
retrieving the vascular filter of FIG. 3 using the retrieval
catheter of FIG. 6 in conjunction with the apparatus of FIG. 4;
[0025] FIGS. 8A-8B are side sectional views depicting a method of
retrieving the vascular filter of FIG. 3 using the retrieval
catheter of FIG. 6 alone;
[0026] FIG. 9 is a side sectional view of an alternative method of
using the apparatus of FIG. 4;
[0027] FIGS. 10A and 10B are side sectional views depicting an
alternative embodiment of the apparatus of FIG. 4;
[0028] FIGS. 11A and 11B are side sectional views depicting another
alternative embodiment of the apparatus of FIG. 4;
[0029] FIG. 12 is a side view of a further alternative embodiment
of the apparatus of FIG. 4 incorporated into the vascular filter of
FIG. 3;
[0030] FIGS. 13A-13C are side sectional views depicting a method of
using apparatus of FIG. 12;
[0031] FIG. 14 is a side view of yet another alternative embodiment
of the apparatus of FIG. 4 incorporated into the vascular filter of
FIG. 3; and
[0032] FIGS. 15A-15C are side sectional views depicting a method of
using apparatus of FIG. 14.
DETAILED DESCRIPTION OF THE INVENTION
[0033] The present invention is directed to apparatus and methods
for closing the mouth of a vascular filter or similar vascular
device so as to prevent emboli from escaping during contraction and
removal of the vascular filter or device, while reducing the number
of equipment exchanges associated with such removal.
[0034] A number of vascular filters are known for providing distal
protection against embolization in conjunction with a transluminal
diagnostic or therapeutic procedure, such as angioplasty. These
filters generally are deployed distal to a vascular lesion prior to
undertaking a diagnostic or therapeutic procedure, and are designed
to filter emboli liberated during the procedure from the patient's
blood. A brief description of a number of these filters is provided
as context for advantages achievable using the apparatus of the
present invention.
[0035] FIG. 1 shows vascular filter 10 described in U.S. Pat. No.
6,129,739 to Khosravi et al., which is incorporated herein in its
entirety. Vascular filter 10 includes articulated support hoop 11
carrying blood permeable sac 12. Support hoop 11 is attached to
tube 13 at point 14, and permits guidewire 15 to be rotated
independently of support hoop 11. Blood permeable sac 12 filters
emboli and other undesirable material from blood passing through
the filter, while permitting blood cells to pass freely
therethrough. When an interventional procedure, e.g., angioplasty
or stenting, is completed, vascular filter 10 is retrieved by
partially withdrawing support hoop 11 into the lumen of the
interventional device (e.g., angioplasty catheter), and removing
the catheter and vascular filter.
[0036] FIG. 2 depicts another type of vascular filter suitable for
use with the methods and apparatus of the present invention, and is
described in U.S. Pat. No. 6,152,946 to Broome et al., which is
incorporated herein by reference. Vascular filter 20 includes a
plurality of longitudinally-extending ribs 21 forming frame 22 that
supports mouth 23. Cone-shaped filter 24 is coupled to mouth 23.
Ribs 21 are coupled to collar 25, which is displaced distally along
guidewire 26 to expand and deploy frame 22 and filter 24. Filter 24
includes holes 27 that permit blood to pass through the filter,
while trapping emboli. Vascular filter 20 is collapsed for
retrieval by applying a load against ribs 21 that causes collar 25
to slide proximally, thereby closing the vascular filter.
[0037] Referring now to FIG. 3, another vascular filter suitable
for use with the apparatus and methods of the present invention is
described. Vascular filter 30 is described in detail in co-pending,
commonly assigned U.S. patent application Ser. No. ______, filed
______ (Attorney Docket No. EPI-002), and is summarily described
here.
[0038] Vascular filter 30 preferably includes self-expanding
support hoop 31 mounted on suspension strut 32, and supports blood
permeable sac 33. Blood permeable sac 33 comprises a biocompatible
polymeric material having a multiplicity of pores. Suspension strut
32 is affixed at proximal end 34 to tube 35, and positions support
hoop 31 approximately concentric to tube 35 when disposed in a
substantially straight length of vessel, but advantageously permits
the support hoop to become eccentrically displaced relative to
support tube 35 when the filter is deployed in a curved vessel.
[0039] Distal end 36 of blood permeable sac 33 is illustratively
mounted to nose cone 37, which is in turn mounted to tube 35.
Filter 30 is mounted on guidewire 38 between proximal stop 39 and
enlarged floppy tip 40 of the guidewire, which functions as a
distal stop. Tube 35 permits guidewire 38 to rotate independently
of filter 30, thereby permitting floppy tip 40 of the guidewire to
be directed within the vessel without causing the blood permeable
sac to become wrapped around guidewire 38.
[0040] Referring now to FIGS. 4A and 4B, apparatus constructed in
accordance with the principles of the present invention is
described. Apparatus 50 of the present invention, referred to
hereinafter as a "retrieval adapter," permits a conventional
interventional device, such as an angioplasty catheter or stent
delivery system, to be employed in retrieving a vascular filter of
the types shown in FIGS. 1-3.
[0041] Adapter 50 preferably includes curved distal end 51 having
expansion slits 52, opening 53, tubular body 54 having internal
lumen 55, and tapered proximal region 56. Optionally, adapter 50
may include helical coil 57 embedded in wall 58 to reinforce the
adapter. Adapter 50 preferably is constructed of a thin
biocompatible material, such as polyethylene, polypropylene,
polyurethane, polyester, polyethylene terephthalate, nylon,
polytetrafluoroethylene, or Pebax.RTM., however, any other suitable
biocompatible material or a combination of such materials may be
used, if desired.
[0042] Adapter 50 preferably is constructed so that it has
sufficient stiffness to be urged along guidewire 59 and through
curved vasculature within a patient's circulatory system. Tapered
proximal region 56 enables adapter 50 to be coupled to a
conventional interventional device, such as an angioplasty catheter
or stent delivery catheter. Adapter 50 has sufficient stiffness so
as to not buckle or kink when being urged into engagement with a
previously deployed vascular filter during filter retrieval.
[0043] Distal end 51 preferably has a smooth, rounded tip to reduce
the risk of adapter 50 from catching a flap of dissected tissue or
on a stent deployed within a vessel. Expansion slits 52 permit the
curved portions of distal end 51 to expand to accept a vascular
filter when adapter 50 is advanced along guidewire 59, so that
opening 53 at least partially accommodates a portion of a deployed
vascular filter. Adapter 50 optionally may comprise a radiopaque
material, e.g., a barium sulfate-infused (BaSO.sub.4) polymer or by
using metal markers, to permit viewing of the adapter using a
fluoroscope. In addition, coil 57 also may comprise a radiopaque
material.
[0044] Tapered region 56 is configured so that it engages the
interior or exterior surface of a conventional interventional
device, such as an angioplasty catheter or stent delivery system.
Tapered region 56 also aids in disposing adapter 50 concentric with
respect to guidewire 59. In accordance with the principles of the
present invention, adapter 50 is delivered at the same time as an
interventional device to be used for the diagnostic or therapeutic
treatment. Accordingly, adapter 50 provides a significant
improvement over previously known filter retrieval systems, by
eliminating the need for a separate catheter exchange to retrieve
the vascular filter.
[0045] Optionally, adapter 50 may be bonded to the distal end of
the interventional device using a standard biocompatible adhesive,
press fitting, or other suitable means. For example, the internal
surface of lumen 55 at tapered proximal end 56 may be coated with a
pressure-sensitive adhesive. A clinician may then couple adapter 50
to the distal end of an interventional device and apply pressure to
fix the adapter to the device. The adapter then is delivered with
the interventional device, and upon completion of the diagnostic or
therapeutic procedure, is used to retrieve the vascular filter.
Alternatively, adapter 50 may be provided in a kit including a
vascular filter mounted on a guidewire (not shown).
[0046] Referring now to FIGS. 5A and 5B, a method of employing the
adapter of FIG. 4 to recover a vascular filter is described. In
FIG. 5A, vascular filter 30 of FIG. 3 is shown deployed along
guidewire 38. After insertion of guidewire 38 and deployment of
vascular filter 30, adapter 50 is mounted to the distal end of
interventional device 60, illustratively an angioplasty catheter.
Adapter 50 and angioplasty catheter 60 then are advanced along
guidewire 38 to a location just proximal of, or in contact with,
the vascular filter, where angioplasty catheter 60 is used to treat
vascular disease. Inflation of the balloon of angioplasty catheter
60 causes emboli E to be liberated from the lesion, and be carried
by the blood flow into filter 30.
[0047] With respect to FIG. 5B, after the interventional procedure
is completed, the balloon of angioplasty catheter 60 is deflated
and catheter 60 is advanced distally along guidewire 38 to bring
adapter 50 into contact with filter 30. Filter 30 preferably is
received within distal end 51 of adapter 50 when the adapter is
advanced further in the distal direction. Alternatively, adapter 50
may receive at least a portion of filter 30 by retracting guidewire
38 proximally while holding angioplasty catheter 60 and adapter 50
stationary.
[0048] The degree to which vascular filter 30 is enclosed within
adapter 50 may be varied depending on treatment requirements. This
may be accomplished by altering the size of adapter 50 or by
controlling the movement of catheter 60 along guidewire 38. For
example, in some cases it may be sufficient to enclose the mouth of
filter 30 within adapter 50 to facilitate retrieval. In such a
situation, adapter 50 may be constructed so that it is somewhat
smaller than the length of filter 30, so only the mouth of the
device fits into the adapter. In other situations, however, it may
be desired to enclose some or all of filter 30 within adapter 50,
and in such a case adapter 50 may be constructed so that it is
somewhat larger than the length of vascular filter 30.
[0049] Referring now to FIG. 6, a retrieval catheter 70 constructed
in accordance with the principles of the present invention is
described. Catheter 70 preferably includes tubular body 71, support
wire 72, radiopaque marker 73 and opening 74. Body 71 and internal
lumen 74 preferably are constructed to a have a diameter sufficient
to accommodate an angioplasty catheter and a vascular filter such
as described hereinabove with respect to FIGS. 1-3.
[0050] Body 71 preferably is fabricated from a thin biocompatible
material, such as polyethylene, polypropylene, polyurethane,
polyester, polyethylene terephthalate, nylon,
polytetrafluoroethylene, polyimid, or Pebax.RTM.. Body 71 also is
sufficiently stiff to be advanced along a guidewire through curved
vasculature, and to retrieve a vascular filter, without buckling or
kinking. Retrieval catheter 70 may be made radiopaque by using
metal marker 73 or by constructing it of a radiopaque material such
as a barium sulfate-infused (BaSO.sub.4) polymer.
[0051] Retrieval catheter 70 may be mounted over a conventional
interventional devices, such as an angioplasty catheter or stent
delivery system, prior to inserting the interventional device into
the patient's vasculature. For example, to mount retrieval catheter
70 on an angioplasty catheter, the distal end of the angioplasty
catheter is inserted through distal end 75 of body 71, and the body
then is retracted proximally on the angioplasty catheter until body
71 is disposed proximally of the balloon of the angioplasty
catheter, as shown in FIG. 7A. Such backloading of the retrieval
catheter is required because the inflation port of a typical
angioplasty catheter precludes mounting retrieval catheter 70 from
the proximal end of the angioplasty catheter.
[0052] A first mode of using retrieval catheter 70 is now described
with respect to FIGS. 7A-7C. In FIG. 7A, an initial step of a
treatment procedure is depicted, wherein vascular filter 30 is
disposed at a distal end of guidewire 38, just distal of adapter
50, interventional device 60, and retrieval catheter 70. Adapter 50
and retrieval catheter 70 are mounted to interventional device 60
prior to insertion along guidewire 38. After completion of the
interventional procedure, the balloon of interventional device 60
is deflated, and the interventional device is urged in the distal
direction to cause adapter 50 to contact with filter 30.
[0053] As shown in FIG. 7B, filter 30 may be received within the
distal end 51 of adapter 50 when it is advanced further in the
distal direction. In particular, adapter 50 is advanced by moving
interventional device 60 along guidewire 38 so that it at least
partially surrounds filter 30. Alternatively, adapter 50 may
receive at least a portion of filter 30 by retracting guidewire 38
in the proximal direction while holding interventional device 60
stationary.
[0054] Next, as shown in FIG. 7C, retrieval catheter 70 is advanced
distally so that filter 30 and adapter 50 are received within lumen
74 of retrieval catheter 70. In this manner it is possible to
reduce the risk that the filter or adapter catches on other
material, e.g., a stent, deployed within the patient's vessel
during removal.
[0055] FIGS. 8A and 8B depict an alternative mode of using
retrieval catheter 70 to retrieve a vascular filter without using
adapter 50. In FIG. 8A, an initial step of a treatment procedure is
depicted, wherein vascular filter 30 is disposed at a distal end of
guidewire 38 followed by the balloon of an interventional device 60
and previously mounted retrieval catheter 70. After completing an
interventional procedure, the balloon of interventional device 60
is deflated and advanced toward filter 30.
[0056] As shown in FIG. 8B, retrieval catheter 70 is then advanced
distally so that the distal end of interventional device 60 and
filter 30 are received in lumen 74 of the retrieval catheter. In
this manner, the risk that emboli will escape from filter 30 is
reduced. In addition, because body 71 of retrieval catheter 70
completely encloses filter 30, the risk that a portion of the
filter sac could become entangled with a stent strut is also
diminished. Alternatively, retrieval catheter 70 may be held
stationary, and filter 30 retracted in the proximal direction into
lumen 74.
[0057] In FIG. 9, an alternative embodiment of a retrieval adapter
constructed in accordance with the principles of the present
invention is described. Adapter 80 is substantially similar to
retrieval adapter 50 of FIG. 4, except that tapered proximal end 81
is configured to abut against the distal end of interventional
device 60, rather than to couple together as shown in FIG. 5A.
[0058] FIGS. 10A and 10B depict another alternative embodiment of
the apparatus of the present invention. Adapter 90 is substantially
similar to adapter 50 of FIG. 4, except that distal end 91 is not
curved as in FIG. 4A, but instead includes a circular opening
having a smooth, rounded edge. Lumen 92 preferably is of sufficient
size to accommodate at least a portion of a deployed filter,
thereby forming a close fit around at least a portion of the mouth
of the filter.
[0059] FIGS. 11A and 11B depict yet another alternative embodiment
of the apparatus of the present invention. Adapter 100 is
substantially similar to adapter 50 of FIG. 4, except that distal
end 101 is not curved as in FIG. 4A, but instead includes an
oblique opening 102 into lumen 103. Opening 102 preferably includes
a smooth, rounded edge. As for the previously-described
embodiments, lumen 103 preferably is of sufficient size to
accommodate at least a portion of a deployed filter, and thus form
a close fit around at least a portion of the mouth of the
filter.
[0060] Each of adapters 50, 80, 90 and 100 may be coupled to (or
disposed adjacent to) the distal end of an interventional catheter
so that the adapter is delivered to a treatment site at the same
time as the working element (i.e., balloon or stent) of the
interventional device. Such concurrent delivery eliminates the
steps of removing the interventional device from the patient's
vessel and inserting a separate retrieval sheath to the treatment
site along the guidewire.
[0061] Referring now to FIG. 12, a further alternative embodiment
of the apparatus of the present invention is described. In this
embodiment, retrieval adapter 110 is similar in construction to
retrieval adapter 50 of FIG. 4, except that adapter 110 is
pre-mounted on suspension strut 32 of vascular filter 30. In
particular, adapter 110 includes lumen 112 and tapered proximal
region 114.
[0062] In operation, an interventional device may be advanced along
guidewire 38 until it abuts proximal end 114 of adapter 110,
pushing the adapter distally along suspension strut 32 towards
support hoop 31 of filter 30, until support hoop 31 is received
within lumen 112. The extent to which adapter 110 receives support
hoop 31 may of course be determined by the length of adapter 110.
Alternatively, adapter 110 may collapse and retrieve vascular
filter 30 by retracting guidewire 38 such that filter 30 is
retracted proximally towards the adapter while holding the
interventional device stationary.
[0063] FIGS. 13A-13C depict one method of using the apparatus of
FIG. 12. In FIG. 13A, during an initial step of an interventional
procedure, filter 30 with pre-mounted retrieval adapter 110 is
deployed in a vessel (not shown). A conventional interventional
device 60, illustratively an angioplasty catheter, is then advanced
along guidewire 38 until distal end 61 of the interventional device
is disposed just proximal of, or in contact with, the proximal end
of the adapter. Preferably, the adapter is positioned sufficiently
far from the proximal end of the vascular filter that small
longitudinal movements of interventional device 60 attendant upon
use of that device do not cause distal end 61 to impinge against
tapered proximal region 114 of adapter 110. It will of course be
recognized that in some applications, e.g., where the vessel is
short, some contact between the adapter and vascular filter can be
accommodated.
[0064] Interventional device 60 then is used to perform the desired
diagnostic or therapeutic treatment, during which emboli E may
become dislodged from the vessel wall. Those emboli travel with
antegrade blood flow and are captured in blood permeable sac 33 of
filter 30. After completion of this procedure, the balloon of the
interventional device is deflated and the interventional device is
advanced along guidewire 38 in the distal direction to bring distal
end 61 of the interventional device into abutment with tapered
proximal region 114 of adapter 110, as shown in FIG. 13B.
[0065] With respect to FIG. 13C, continued advancement of
interventional device 60 in the distal direction causes support
hoop 31 of filter 30 to at least partially enter lumen 112 of
adapter 110, thereby causing the support hoop to close and closing
the mouth of filter sac 33. Alternatively, adapter 110 may be
caused to at least partially surround support hoop 31 by retracting
guidewire 38 proximally while holding interventional device 60
stationary.
[0066] The degree to which vascular filter 30 is captured in
adapter 110 depends on the length of lumen 112 within adapter 110
and also is limited by the length of the support hoop when folded
over guidewire 38. Specifically, vascular filter 30 may be received
within lumen 112 of adapter 110 until the point on support hoop 31
opposite to the connection to suspension strut 32 is urged against
guidewire 38.
[0067] Because closing the vascular filter may prevent the vascular
device from being re-deployed, it may be desirable to prevent the
inadvertent closing of vascular filter 30. Such inadvertent closing
may be prevented by using a safety system deployed along guidewire
38, as shown in the embodiment of FIG. 14.
[0068] In FIG. 14, vascular filter 30 is disposed on guidewire 38
and includes adapter 110 disposed on suspension strut 32 in the
same manner as depicted in FIG. 12. In accordance with this aspect
of the present invention, guidewire 38 includes safety system 120
comprising screw 122, nut 124 and stop 126. Preferably, these
components are constructed of a high strength plastic or metal
alloy, such as stainless steel.
[0069] Safety system 120 is intended to prevent an interventional
device, such as a balloon catheter or stent delivery system, from
accidentally closing vascular filter 30. Screw 122 and stop 126
preferably are fixed on guidewire 38, while nut 124 is configured
to move freely along guidewire 38 between screw 122 and stop 126.
Stop 126 restricts movement of nut 124 in the proximal direction,
while screw 122 selectively restricts movement of nut 124 in the
distal direction.
[0070] Nut 124 may be advanced past screw 122 by rotating guidewire
38 such that the threads of the screw mesh with the threads of the
nut, thus advancing the nut over and past the screw until the nut
is disposed distally of the screw, i.e., between filter 30 and
screw 122. When nut 124 is disposed between screw 122 and stop 126,
it prevents the interventional device from advancing distally
toward adapter 110 until guidewire 38 is intentionally rotated.
Once the intended diagnostic or therapeutic procedure is completed,
however, nut 124 is moved to a position between filter 30 and screw
122 by rotating guidewire 38, and then the interventional device
may be advanced distally over stop 126 and screw 122 to urge nut
124 into engagement with adapter 110, thereby closing filter
30.
[0071] FIGS. 15A-15C depict a method of using the apparatus of FIG.
14. In FIG. 15A, during an initial step of an interventional
procedure, filter 30 is deployed in a vessel (not shown) and
includes adapter 110 disposed on suspension strut 32, and safety
system 120 disposed on guidewire 38. A conventional interventional
device 60, illustratively an angioplasty catheter, is advanced
along guidewire 38 and then used to effect a desired diagnostic or
therapeutic treatment, during which emboli E may become dislodged
from the vessel wall. Those emboli travel with antegrade blood flow
and are captured in blood permeable sac 33 of filter 30.
[0072] After completion of this procedure, the balloon of the
interventional device is deflated and the interventional device is
advanced along guidewire 38 in the distal direction and over stop
126 until distal end 61 of the interventional device contacts nut
124. The distal end of interventional device 61 may push nut 124
until it is in direct contact with screw 122.
[0073] Next, as shown in FIG. 15B, nut 124 is advanced over and
past screw 122 by rotating guidewire 38 so that the threads of nut
124 mesh with and advance over the threads of screw 122.
Interventional device 60 is then advanced distally over screw 122
to urge nut 124 into contact with the proximal end of adapter 110.
As shown in FIG. 15C, further advancement of interventional device
60 in the distal direction causes nut 124 to urge adapter 110
distally, whereby support hoop 31 is received at least partially
within lumen 112 of the adapter. In this manner filter 30 may be
collapsed for retrieval with little effort and without an
additional equipment exchange or additional retrieval sheath. As
for the previous embodiments, adapter 110 alternatively may be
caused to at least partially surround support hoop 31 by retracting
guidewire 38 proximally while holding interventional device 60
stationary.
[0074] Although the present invention is illustratively described
in the context of interventional devices such as angioplasty
catheters and stent delivery systems, the apparatus of the present
invention advantageously may be employed with atherectomy
catheters, embolectomy catheters, vascular mapping catheters or any
other suitable diagnostic or therapeutic interventional device, if
desired.
[0075] 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.
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