U.S. patent application number 10/361217 was filed with the patent office on 2003-09-18 for blood filter and method for treating vascular disease.
This patent application is currently assigned to B. Braun Medical SA. Invention is credited to O'Connell, Paul T..
Application Number | 20030176888 10/361217 |
Document ID | / |
Family ID | 23175966 |
Filed Date | 2003-09-18 |
United States Patent
Application |
20030176888 |
Kind Code |
A1 |
O'Connell, Paul T. |
September 18, 2003 |
Blood filter and method for treating vascular disease
Abstract
A filter is provided that is convertible from a filter
configuration to an open, stent-like configuration. The filter
includes a plurality of intraluminal filter elements (filter legs)
that may be formed into a single cone or dual cone filter
structure. A retainer secures the filter legs in the filter
configuration upon initial deployment within a vessel. The retainer
is then either self-releasing or removable to permit the filter
legs to expand from the filter configuration into what may
generally be described as an open or stent-like configuration. A
filter web extends, at least in part, between the filter legs.
Inventors: |
O'Connell, Paul T.;
(Evanston, IL) |
Correspondence
Address: |
MARSHALL, GERSTEIN & BORUN
6300 SEARS TOWER
233 SOUTH WACKER
CHICAGO
IL
60606-6357
US
|
Assignee: |
B. Braun Medical SA
|
Family ID: |
23175966 |
Appl. No.: |
10/361217 |
Filed: |
February 10, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10361217 |
Feb 10, 2003 |
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09564141 |
May 3, 2000 |
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6517559 |
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09564141 |
May 3, 2000 |
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09304111 |
May 4, 1999 |
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6135464 |
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Current U.S.
Class: |
606/200 |
Current CPC
Class: |
A61F 2/012 20200501;
A61F 2210/0004 20130101; A61F 2/0103 20200501; A61F 2230/0069
20130101; A61F 2/0105 20200501; A61F 2/848 20130101; A61F 2230/005
20130101; A61F 2002/018 20130101; A61F 2230/0006 20130101; A61F
2002/016 20130101; A61F 2250/0071 20130101; A61F 2230/008 20130101;
A61F 2/86 20130101; A61F 2230/0078 20130101; A61F 2230/0067
20130101 |
Class at
Publication: |
606/200 |
International
Class: |
A61M 029/00 |
Claims
I claim:
1. A filter adapted for use in treating vascular disease, the
filter comprising: a plurality of interconnected intraluminal
filter elements, the intraluminal filter elements arranged to be
disposed in a filter configuration within the lumen of a blood
vessel, a releasable retainer joining the intraluminal filter
elements in the filter configuration, and wherein upon release of
the releasable retainer the intraluminal filter elements convert to
an open configuration.
2. The filter of claim 1, further comprising a spring formed
integrally with the plurality of intraluminal filter elements.
3. The filter of claim 1, further comprising a filter web
interconnecting the filter elements
4. The filter of claim 3, wherein the filter web extends between
each adjacent intraluminal filter element.
5. The filter of claim 3, wherein the filter web is formed
integrally with the intraluminal filter elements.
6. The filter of claim 1, further comprising means for passively
releasing the releasable retainer.
7. The filter of claim 1, further comprising means for releasing
the releasable retainer after a predetermined time period.
8. The filter of claim 1, wherein the releasable retainer comprises
a biodegradable material.
9. The filter of claim 1, further comprising means for actively
releasing the releasable retainer.
10. The filter of claim 1, wherein the releasable retainer
comprises a coupling formed with a plurality of catches, each of
the catches respectively engaged with one of the plurality of
intraluminal filter elements.
11. The filter of claim 1, wherein the releasable retainer
comprises a breakable band engaging each of the plurality of
intraluminal filter elements.
12. The filter of claim 1, further comprising means for releasing
the releasable retainer responsive to an energy stimulus.
13. The filter of claim 1, further comprising means for releasing
the releasable retainer responsive to a chemical stimulus.
14. A filter for use in treating vascular disease comprising: a
plurality of interconnected intraluminal filter elements each
having a superior end and an inferior end, a plurality of orienting
members secured to and extending from respective ones of the
intraluminal filter elements, a releasable retainer joining the
superior ends in a filter configuration, and wherein upon release
of the releasable retainer the intraluminal filter elements convert
to an open configuration.
15. The filter of claim 14, further comprising a plurality of
members joined to the intraluminal filter elements to restore the
superior ends to an open configuration upon release of the
retainer.
16. The filter of claim 14, further comprising a filter web
interconnecting the intraluminal filter elements.
17. The filter of claim 16, where in the filter web extends between
each adjacent intraluminal filter element.
18. The filter of claim 16, wherein the filter web is formed
integrally with the intraluminal filter elements.
19. The filter of claim 14, wherein each orienting member is formed
integrally with a respective intraluminal filter element.
20. The filter of claim 14, wherein each orienting member comprises
a portion of the respective intraluminal filter element extending
substantially parallel to an axis of filtration.
21. The filter of claim 14, wherein each orienting member comprises
an elongate portion of the respective intraluminal filter element
extending from the respective superior end and radially outwardly
from the retainer.
22. The filter of claim 14, wherein each orienting member comprises
a loop extending between the inferior ends of adjacent intraluminal
filter elements.
23. The filter of claim 14, further comprising means for passively
releasing the releasable retainer.
24. The filter of claim 14, wherein the releasable retainer
comprises a biodegradable material.
25. The filter of claim 14, further comprising means for actively
releasing the releasable retainer.
26. The filter of claim 14, wherein the releasable retainer
comprises a coupling formed with a plurality of catches, each of
the catches respectively engaged with one of the plurality of
intraluminal filter elements.
27. The filter of claim 14, wherein the releasable retainer
comprises a breakable band engaging each of the plurality of
intraluminal filter elements.
28. The filter of claim 14, further comprising means for releasing
the releasable retainer responsive to an energy stimulus.
29. The filter of claim 14, further comprising means for releasing
the releasable retainer responsive to a chemical stimulus.
30. A filter for the treatment of vascular disease comprising: a
plurality of interconnected intraluminal filter elements each
having a superior end and an inferior end, a releasable retainer
securing the intraluminal filter elements in a filter
configuration, the releasable retainer being disposed at a location
along the intraluminal filter elements between the superior and
inferior ends, and wherein upon release of the releasable retainer
the intraluminal filter elements convert to an open
configuration.
31. The filter of claim 30, further comprising a first member
secured to the intraluminal filter elements adjacent the superior
ends for retaining the superior ends.
32. The filter of claim 31, further comprising a second member
secured to the intraluminal filter elements adjacent the inferior
ends for retaining the inferior ends.
33. The filter of claim 30, further comprising a filter web
interconnecting the intraluminal filter elements.
34. The filter of claim 33, wherein the filter web extends between
each adjacent intraluminal filter element.
35. The filter of claim 33, wherein the filter web is formed
integrally with the intraluminal filter elements.
36. A filter adapted for use in treating vascular disease, the
filter comprising: a plurality of interconnected intraluminal
filter elements, the intraluminal filter elements each having a
first end and a second end and arranged to be disposed in a
basket-type configuration within the lumen of a blood vessel, a
releasable retainer joining the first ends and the second ends of
each intraluminal filter element, and wherein upon release of the
releasable retainer the intraluminal filter elements convert to an
open configuration.
37. The filter of claim 36, further comprising a plurality of
members joined to the plurality of intraluminal filter elements
which upon release of the releasable retainer join the intraluminal
filter elements in an open configuration.
38. The filter of claim 36, further comprising a filter web
interconnecting the intraluminal filter elements.
39. The filter of claim 38, wherein the filter web extends between
each adjacent intraluminal filter element.
40. The filter of claim 36, wherein the releasable retainer
comprises a first releasable retainer and a second releasable
retainer.
41. The filter of claim 40, further comprising means for releasing
the first releasable retainer after a first predetermined time
period and a means for releasing the second releasable retainer
after a second predetermined time period.
42. The filter of claim 40, wherein the first releasable retainer
comprises a biodegradable material.
43. The filter of claim 40, wherein the second releasable retainer
comprises a biodegradable material.
44. The filter of claim 40, wherein the first releasable retainer
comprises a first biodegradable material and the second releasable
retainer comprises a second biodegradable material.
45. The filter of claim 40, wherein the first releasable retainer
comprises a coupling formed with a plurality of catches, each of
the catches respectively engaged with one of the plurality of
intraluminal filter elements.
46. The filter of claim 40, wherein the second releasable retainer
comprises a coupling formed with a plurality of catches, each of
the catches respectively engaged with one of the plurality of
intraluminal filter elements.
47. The filter of claim 40, wherein the first releasable retainer
comprises a breakable band engaging each of the plurality of
intraluminal filter elements.
48. The filter of claim 40, wherein the second releasable retainer
comprises a breakable band engaging each of the plurality of
intraluminal filter elements.
49. The filter of claim 40, further comprising means for releasing
the first and second releasable retainers responsive to an energy
stimulus.
50. The filter of claim 40, further comprising means for releasing
the second releasable retainer responsive to an energy
stimulus.
51. The filter of claim 40, further comprising means for releasing
the first and second releasable retainers responsive to a chemical
stimulus.
52. The filter of claim 40, further comprising means for releasing
the second releasable retainer responsive to a chemical
stimulus.
53. A method for treating atherosclerosis comprising the steps of:
operatively disposing a filter within an artery, treating the
artery to remove plaque from an interior wall thereof, collecting
embolic and plaque material in the filter, removing embolic and
plaque material collected within the filter, and converting the
filter, in situ, to an open configuration.
54. The method of claim 53, wherein the step of converting
comprises, actively releasing a retainer member securing the filter
in the filter configuration.
55. The method of claim 53, wherein the step of converting
comprises, providing a passively releasable retainer securing the
filter in the filter configuration.
56. A method for treating vascular disease comprising the steps of:
operatively disposing a filter within a vessel, treating the
vascular disease, collecting the biological debris in the filter,
removing the biological material from the filter, and converting
the filter, in situ, to an open configuration.
57. The method of claim 56, wherein the step of converting
comprises, actively releasing a retainer member securing the filter
in the filter configuration.
58. The method of claim 56, wherein the step of converting
comprises, providing a passively releasable retainer securing the
filter in the filter configuration.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of application
Ser. No. 09/304,111, filed May 3, 1999.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The invention relates generally to devices for the treatment
vascular disease and, more particularly, the invention relates to a
filter device for placement within a blood vessel that is operable
to catch and retain embolic material dislodged during the treatment
of atherosclerotic disease.
[0004] 2. Description of the Related Technology
[0005] Atherosclerotic disease in the coronary and carotid
vasculature is one of the leading causes of morbidity and mortality
in the United States. Atherosclerotic disease can cause
insufficient circulation of oxygenated blood due to luminal
narrowing caused by formation of atherosclerotic plaque. In
addition, atherosclerotic disease can cause thromboembolism.
[0006] Atherosclerosis is a progressive, degenerative arterial
disease that leads to occlusion of affected blood vessels, thereby
reducing vessel patency, and hence, blood flow through them. During
the course of this vascular disease, plaques develop on the inner
lining of the arteries narrowing the lumen of the blood vessels.
Sometimes these plaques become hardened by calcium deposits,
resulting in a form of atherosclerosis called arteriosclerosis or
"hardening of the arteries." Atherosclerosis attacks arteries
throughout the body, but the most serious consequences involve
damage to the vessels of the brain and heart. In the brain,
atherosclerosis is the primary cause of strokes, whereas in the
heart, when total blockage of an artery occurs, portions of heart
muscle can die and disrupt the electrical impulses that make the
heart beat.
[0007] The internal carotid artery is an artery often affected by
atherosclerosis. When atherosclerosis is detected in the carotid
artery, physicians need to remove the plaque, thereby restoring
circulation to the brain and preventing a cerebral vascular
accident.
[0008] Treatment for atherosclerosis ranges from preventive
measures such as lowering fat intake and medication to
endarterectomy, balloon angioplasty or atherectomy. In
endarterectomy, the affected artery is surgically opened and plaque
deposits are removed from the lining of the arterial wall.
Occasionally during endarterectomy, large pieces of plaque break
away from the arterial walls and enter the blood stream.
Additionally, thrombotic material may develop if damage to the
arterial wall occurs from the removal of plaque. Dislodged plaque
deposits and thrombotic material, causing a condition called
thromboembolism, may occlude smaller vessels downstream resulting
in a vascular problems and potentially death. Thus, it is common
practice by one skilled in the art to capture dislodged plaque, or
any thrombotic material, by using a vacuuming procedure throughout
the duration of the endarterectomy procedure. Although a
significant percentage of plaque and thrombotic material is
captured by this vacuuming procedure, pieces of plaque as well as
thrombotic material inevitably escape.
[0009] Balloon angioplasty is a another method of treating
atherosclerosis. In balloon angioplasty, a balloon-tipped catheter
is inserted through the skin into the vessel and maneuvered to the
lesion in the artery. The balloon tipped catheter is threaded
through the lesion and inflated, increasing the vessel lumen to
improve blood flow at the site. After deflating the balloon, stents
are often inserted to keep the lumen of the vessel open, maintain
blood flow and provide a scaffolding for tissue growth. Although
balloon angioplasty and stenting are alternative methods of
treatment, recent studies have documented adverse side effects
associated with carotid stenting and, therefore, such procedures
may not be as desirable as endarterectomy.
[0010] An additional method of treatment, atherectomy, is a
procedure during which the plaque in coronary arteries is ground
into minuscule particles that the body can clean from the
bloodstream. Occasionally, during such procedures, large pieces of
plaque break away from the arterial walls and enter the blood
stream. As described above, this plaque debris can not be processed
by the body and, therefore, must be vacuumed from the bloodstream
to prevent the plaque from clogging arteries in the brain or
elsewhere.
[0011] The primary use of blood filters historically has been to
prevent pulmonary embolism. Blood filters are implanted within a
vein, typically the inferior vena cava, and are intended to trap
large blood clots while allowing blood to pass freely through the
filter around the clot. In most cases trapped blood clots will
normally dissolve over time.
[0012] Most often, blood filters are implanted within the inferior
vena cava from a variety of peripheral vein access sites, for
example, the jugular or femoral veins. An early example of such a
filter was the Mobin-Uddin (MU) umbrella filter, which was
developed and made available by American Edwards Laboratories in
Santa Monica, Calif. in the 1970s. The Mobin-Uddin umbrella was
composed of six flat ELGILOY spokes radiating from a hub and
partially covered by a web designed to capture blood clots. MU
filters were introduced into the body via a cutdown of the jugular
or femoral vein and subsequent passing of a catheter through the
access site to the filter implant site in the infrarenal inferior
vena cava. While this method was an improvement over previous
methods, the MU filter was associated with a high incidence of
occlusion of the inferior vena cava, in which blood flow through
the vena cava was completely obstructed.
[0013] In the mid-197's, the Kimray-Greenfield (KG) vena cava
filter was introduced. The original KG filter is conical in shape
and is composed of six stainless steel wires equally spaced with
its apex cephalad. Although the filter was originally placed using
a local cutdown of the jugular or femoral vein, it was later
adapted to be inserted percutaneously. The KG filter is designed to
capture clots 7 mm or greater in diameter, holding the clots in the
infrarenal vena cava until the body's own lytic system dissolves
the clot. The principal drawbacks of the KG filter are the
possibility of tilting and filter migration, often related to a
failure to open, or untimely ejection of the filter from the
introducer.
[0014] Subsequent versions of the so-called Greenfield filter were
developed to reduce the size of the introducer catheter to
facilitate percutaneous introduction. Other vena cava filters were
introduced in the United States in the late 1980s, including the
Vena Tech--LGM vena cava filter, the Bird's Nest vena cava filter,
and the Simon-Nitinol vena cava filter. The Vena Tech--LGM filter
is a conical filter made from the PHYNOX alloy, with longitudinal
stabilizing legs in addition to the intraluminal cone. The Bird's
Nest filter is a "nest" of stainless steel wire which is wound into
the vena cava, while the Simon Nitinol filter is a two-stage filter
made from nickel-titanium alloy with a conical lower section and a
petal-shaped upper section. All of these devices are permanent
implants which cannot be removed from the body without a major
surgical intervention.
[0015] Among numerous vena cava filters introduced in Europe but
never brought to the United States was the optimal central trapping
(OPCETRA) filter. The OPCETRA filter has two main parts: a main
basket with ten, long stainless steel wire arms and a distal basket
with five, short stainless steel wire arms. This design gives the
filter an hourglass shape which provides a self-orienting structure
for the filter within the lumen of a blood vessel. The OPCETRA
filter was also a permanently implanted vena cava filter.
[0016] All of the above-identified vena cava filters are inserted
into the body by passing the filter through a catheter to the site
of deployment in the infrarenal inferior vena cava. After ejection
from the catheter, these filters open or are manually deployed
until the filter anchoring elements engage the vessel wall. These
filters often have hooks or some other means by which the filter
becomes fixed permanently to the vessel wall.
[0017] For an important subset of patients, in particular young
trauma patients and patients undergoing total hip or knee
replacement surgery, the risk of embolism is short-term and limited
to a definable period of time. Because of the long-term risks
associated with implantation of a permanent blood filter, including
venous stasis due to caval occlusion and its related complications,
patients whose risk period is limited are not considered good
candidates for permanent blood filters. The search for an
appropriate temporary therapy for such patients lead to the
development of temporary, tethered removable filters.
[0018] Tethered temporary filters are attached to a catheter and
are implanted in the infrarenal vena cava with the tethering
catheter extending out of the puncture site in the neck or groin,
or buried subcutaneously within the soft tissues in the patient's
neck. The tether remains coupled to the filter after deployment.
The tether is then used to retrieve the filter. The potential for
septic complications associated with the tethering catheter exiting
the neck or groin require removal of such devices within fourteen
days of placement. Risk periods for embolism in such patients,
however, can extend up to twenty-one weeks.
[0019] Temporary retrievable filters which are not attached to a
tethering catheter have a construction similar to some versions of
permanent filters. A hook or similar grasping structure is provided
to allow a snare to engage the filter during the retrieval
procedure. The filter in its entirety is then retrieved using a
snare by drawing it into a catheter. However, to ensure the filter
does not migrate with the vessel, barbs, anchors or similar
structures must be used to engage the filter with the interior wall
of the vessel for retaining it in place. These anchors make removal
without injuring the vessel difficult. Moreover, after a relatively
short period of time the portion of the filter legs in contact with
the vessel wall are incorporated by endothelial tissue making
retrieval difficult or impossible.
[0020] More recently, it has been proposed to provide a removable
filter in two parts. An anchoring part of the filter engages the
vessel walls, and become incorporated by endothelial tissue. A
filter part is releasably coupled to the anchoring part. After the
risk of embolism has passed, the filter part may be retrieved using
a snare and catheter.
[0021] Thus, there is a need for a temporary, convertible blood
filter that can be inserted into a vessel to treat vascular
disease. Additionally, there is a need for a temporary, convertible
blood filter to catch and retain biological debris during
procedures such as endarterectomy, angioplasty, or atherectomy, yet
be openable to fully restore vessel patency following the
treatment.
SUMMARY OF THE INVENTION
[0022] The invention provides a filter arranged to be disposed
within a blood vessel. The filter includes intraluminal filter
elements and is convertible from a filter configuration to an open,
stent-like configuration.
[0023] The invention also provides a method of treating embolism
and atherosclerotic disease using a filter constructed in
accordance with the invention.
[0024] In a preferred embodiment, the filter device includes a
plurality of elements formed into a single cone or dual cone filter
structure. A retainer secures the elements in an intraluminal
filter configuration upon initial deployment within a vessel. The
retainer is then either self-releasing or removable to permit the
legs to expand from the filter configuration into what may
generally be described as an open or stent-like configuration
substantially, totally reopening the lumen.
[0025] To maintain stability within the lumen, superior and/or
inferior ends of the filter can be formed with a small barb or hook
that engages the interior wall of the vessel.
[0026] A single cone filter in accordance with the invention
includes a plurality of intraluminal filter elements, the superior
ends of which are joined by a releasable retainer. In one preferred
embodiment, a filter web extends between the plurality of
intraluminal elements. In another preferred embodiment, the single
cone filter has filter legs which are constrained in the filter
configuration. In yet another preferred embodiment, a spring member
couples to the legs of the single cone filter to urge them radially
outward and revert the filter to an open or stent-like
configuration. When in the open configuration, the lumen is
substantially unobstructed by the filter.
[0027] A dual cone filter in accordance with a preferred embodiment
of the invention has intraluminal filter elements joined by a
releasable retainer at a location between their superior and
inferior ends. In one embodiment, a filter web extends between the
intraluminal filter elements. This dual cone shape advantageously
improves the self-orienting mechanism of the filter. A spring may
join the legs to urge them from the dual cone or hourglass shape
into a stent-like configuration upon release of the retainer.
Alternatively, the legs may be formed to provide the restoring
force.
[0028] In still another embodiment, the filter device has
intraluminal elements made of a biodegradable material.
[0029] In yet another embodiment, the filter device has a
releasable retainer joining both ends of the of the intraluminal
elements to create a basket-like configuration. The retainer may be
self-releasing or removable to permit the intraluminal filter
elements to expand from a basket-like configuration into a single
cone configuration and subsequently into what may generally be
described as an open or stent-like configuration.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] The invention will be described with reference to the
following detailed description of several preferred embodiments
with reference to the drawings wherein like reference numerals are
used to represent like elements, and in which:
[0031] FIG. 1 is a side view of a filter in a filter configuration
within a blood vessel and having a dual cone structure in
accordance with a preferred embodiment of the invention;
[0032] FIG. 2 is a view of an intraluminal filter element of the
filter shown in FIG. 1 shown in an open configuration;
[0033] FIG. 3 is a detailed view of the small barb or hook on the
end of the intraluminal filter element of FIG. 1;
[0034] FIG. 4 is a cross-section view taken along line 4-4 of FIG.
3;
[0035] FIG. 5 is a view of the mesh of wires forming the filter
illustrated in FIG. 1;
[0036] FIG. 6 is a side view of the filter illustrated in FIG. 1
and further shown in an open, stent-like configuration;
[0037] FIG. 7 is a side view of a filter similar to that shown in
FIG. 1 and illustrating a releasable retainer restraining the
plurality of intraluminal filter elements in a filter configuration
at a location between the superior and inferior ends of the
elements;
[0038] FIG. 8 is an bottom view of the filter shown in FIG. 6;
[0039] FIG. 9 is an enlarged side view of a actively releasable
retainer that may be used with the filter illustrated in FIG.
1;
[0040] FIG. 10 is a cross-section view taken along line 10-10 of
FIG. 9;
[0041] FIG. 11 is a detailed view of the intraluminal filter
elements and tubular apertures of FIG. 10;
[0042] FIG. 12 is a side view of a single cone filter in a filter
configuration, the filter including axially extending orientation
members;
[0043] FIG. 13 is a side view of an actively releasable retainer
with a hook that may be used with the filter shown in FIG. 12;
[0044] FIG. 14 is a side view of a passively releasable retainer
that may be used with the filter shown in FIG. 12;
[0045] FIG. 15 is a top cross-sectional view of the restrained
intraluminal filter elements contained within the releasable
retainer shown in FIG. 13;
[0046] FIG. 16 is a top cross-sectional view of the restrained
intraluminal filter elements contained within the releasable
retainer shown in FIG. 14;
[0047] FIG. 17 is a cross-sectional view taken along line 17-17 or
FIG. 12;
[0048] FIG. 18 is a top view of the filter shown in FIG. 12 in an
open, stent-like configuration;
[0049] FIG. 19 is a side view of a filter in a filter configuration
having axially extending orientation members;
[0050] FIG. 20 is a cross-sectional view taken along line 20-20 or
FIG. 19;
[0051] FIG. 21 is a top view of the filter shown in FIG. 19 in an
open, stent-like configuration;
[0052] FIG. 22 is a side view of a filter in a filter configuration
having axially extending orientation members;
[0053] FIG. 23 is a side view of the filter shown in FIG. 22 in an
open, stent-like configuration;
[0054] FIG. 24 is a side view of a filter in a filter configuration
having a plurality of intraluminal filter elements that include a
corrugated structure;
[0055] FIG. 25 is a cross-sectional view taken along line 25-25 or
FIG. 24;
[0056] FIG. 26 is a top view of the filter shown in FIG. 24 in an
open, stent-like configuration;
[0057] FIG. 27 is a side view of a filter in a filter configuration
with a plurality of intraluminal filter elements having axially
extending orientation members;
[0058] FIG. 28 is a side view of a filter in a filter configuration
with adjacent intraluminal filter elements joined by axially
extending orientation members;
[0059] FIG. 29 is a side view of a filter in a filter configuration
having adjacent intraluminal filter elements joined by a wire mesh
and having axially extending orientation members;
[0060] FIG. 30 is a top view of the filter shown in FIG. 29;
[0061] FIG. 31 is a top view of the filter shown in FIG. 29 in an
open, stent-like configuration;
[0062] FIG. 32 is a side view of a device inserted into the lumen
near a filter in a filter configuration in accordance with the
invention for releasing the retainer;
[0063] FIG. 33 is a side view of the filter shown in FIG. 32 in an
open, stent-like configuration;
[0064] FIG. 34 is a side view of a filter having two retainers
which form a basket-type filter structure;
[0065] FIG. 35 is a side view of the filter in FIG. 34 in a single
cone configuration;
[0066] FIG. 36 is a side view of the filter in FIG. 34 in an open,
stent-like configuration;
[0067] FIG. 37 is a side view of a filter in a filter configuration
within a blood vessel and having a dual cone structure in
accordance with a preferred embodiment of the invention;
[0068] FIG. 38 is a side view of a filter in a filter configuration
having adjacent intraluminal filter elements joined by a filter web
and having axially extending orientation members;
[0069] FIG. 39 is a side view of an actively releasable retainer
that may used with the filter shown in FIG. 38;
[0070] FIG. 39A is a cross-section view of an actively releasable
retainer similar to the retainer shown in FIG. 10;
[0071] FIG. 40 is a top view of the intraluminal filter elements
connected by the filter web shown in FIG. 38 in a closed, filter
configuration;
[0072] FIG. 41 is a side view of a filter shown in FIG. 38 position
superior to the plaque in an arterial blood vessel;
[0073] FIG. 42 is a side view of the filter shown in FIG. 38
retaining dislodged plaque and thrombotic material;
[0074] FIG. 43 is a side view of the filter shown in FIG. 41 after
plaque has been removed from the filter; and
[0075] FIG. 44 is a side view of the filter shown in FIG. 41 in an
open, stent-like configuration.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0076] Referring generally to FIGS. 1-11, and particularly to FIG.
1, a dual cone blood clot filtration device (filter) 10 in a filter
configuration includes a plurality of intraluminal filter elements
(filter legs) 12, which may be formed using a suitable wire. As
used herein, the term "filter configuration" is used to refer to a
filter according to the invention where the intraluminal filter
elements are joined by a releasable retainer so as to form a filter
structure within the lumen. The term "open configuration" or
"stent-like configuration" is used to refer to a filter according
to the invention where the releasable retainer has been removed,
and the intraluminal filter elements are disposed substantially
adjacent an interior wall of the lumen.
[0077] With continued reference then to FIG. 1, the filter legs 12
each have a blunted superior end 16 and inferior end 18. Superior
and inferior are used in their ordinary sense to refer to the
filter's position within the body. The superior ends 16 are
positioned upstream relative to blood flow, and the inferior ends
18 are positioned downstream relative to blood flow. The direction
of blood flow is indicated in FIG. 1 by the arrow 20. The filter
legs 12 are joined by a releasable retainer 22 at some location
between the superior ends 16 and the inferior ends 18. In FIG. 1,
the releasable retainer 22 secures the filter legs 12 in a dual
cone filter configuration. The filter 10 may have a first spring 24
adjacent the superior ends 16 to urge them radially outwardly and a
second spring 26 adjacent the inferior ends 18 to likewise urge
them radially outward. Alternatively, the filter 10 may have a
plurality of annular, horizontal members joining the filter legs
12. The releasable retainer 22 retains the filter legs 12 in the
intraluminal dual cone filter configuration, e.g., resists the
force exerted on the filter legs 12 by the first spring 24 and the
second spring 26. The first spring 24 and the second spring 26 are
each shown as an expanding annular spring, however, alternative
spring configurations may be used, and several are described in
connection with alternate preferred embodiments of the invention
described below.
[0078] The filter 10 in FIG. 1 is shown inserted into a blood
vessel 28 by a physician using the commonly practiced Seldinger
technique. For percutaneous insertion of the filter 10, a vein is
punctured with a needle, and a guidewire is advanced into the blood
vessel 28 through the needle beyond the desired implantation site.
A catheter consisting of an inner, dilating cannula within an outer
sheath, up to 14 French in diameter, is then advanced into the
vein, over the guidewire. When the desired implantation site is
reached, the inner dilating cannula and guidewire are removed,
leaving the sheath behind. The sheath acts as a conduit to permit
the insertion of the filter. The filter 10, in a collapsed
configuration, is introduced into the sheath and advanced to the
implantation site. Once the filter 10 is in an appropriate
position, the filter 10 is pushed out of the sheath or uncovered
using a pushing catheter. Upon discharge, the filter legs 12 open
and engage the interior wall of the blood vessel 28.
[0079] The filter legs 12 may be a flexible wire and, in one
preferred embodiment, the wires are metallic and round. In such an
embodiment, the wires are preferably a radiopaque and
non-ferromagnetic metal which has been certified for use in
permanently implanted medical devices by the International
Standards Organization (ISO). The wires may, in particular, be a
high cobalt, low ferrous alloy, such as that known as and sold
under the registered trademarks of "PHYNOX" or "ELGILOY" which may
have the composition, by weight percent: cobalt 42%, chromium
21.5%, nickel 18%, iron 8.85%, molybdenum 7.5%, manganese 2% with
the balance made up of carbon and beryllium having a maximum of
0.15% carbon and 0.001% beryllium. The wires may also be composed
of 316L stainless steel or alloys of nickel and titanium known to
be shape-memory metals which are sold and manufactured under the
trademark "NITINOL" or an alloy of tantalum. Filter devices 10
constructed from metals will preferably withstand twelve million
respiratory cycles without mechanical failure and will be
non-thrombogenic.
[0080] FIG. 2 shows a single filter leg 12 of the filter 10. The
filter 10, and each filter leg 12 are constructed so as to
eliminate the possibility of entrapping a guide wire during
insertion of the filter 10 into the lumen of a blood vessel. When
not being restrained by the releasable retainer 22, each filter leg
12 is relatively straight, running parallel to the axis of the
vessel wall 28. Each blunted superior end 16 and inferior end 18
end is flattened and has a small hook or barb 32, best seen in FIG.
3 and FIG. 4, that engages the interior wall of the blood vessel
28, which retain the filter 10 at a desired position within the
blood vessel 28. Each filter leg 12 also includes a partially
corrugated portion 34. Within a relatively short period of time
after implantation, the small hooks or barbs 32 on the superior
ends 16 and inferior ends 18 of the filter legs 12, which are in
contact with the interior wall of the vessel 28, become permanently
connected with the interior wall of the blood vessel 28. The
corrugated portion 34 permits outward expansion of the filter leg
12 after release of the releasable retainer 22 without displacement
of the superior end 16 or the inferior end 18 as the filter is
converted to the stent-like configuration. This arrangement of the
filter leg 12 prevents ripping or tearing of the interior wall of
the blood vessel 28 upon opening of the filter 10 from the filter
configuration shown in FIG. 1 to the open, stent-like configuration
shown in FIG. 6. If the filter leg 12 did not included corrugated
portion 34 upon release of the releasable retainer 22 and as the
filter leg 12 tries to regain its original substantially straight
shape, and with each superior end 16 and interior end 18 engaging
the blood vessel 28, this movement of the filter leg 12 may cause
the superior end 16 and inferior end 18 to be pulled away from the
interior wall of the vessel 28 resulting in injury to the vessel
wall.
[0081] FIG. 5 shows a plurality of filter legs 12 joined by
horizontal connecting members 36 such as by laser welding.
Alternatively, a mesh of wires 38 may be formed by the cutting
application of a laser micro machining tool. In FIG. 6, the mesh of
wires 38 is formed into a stent-like, cylindrical configuration
when the ends of the mesh of wires 38 are permanently laser welded
together. In a preferred embodiment, the filtration device 10 must
be openable to a diameter of not less than "d", preferably about
3.0 cm, yet collapsible to a diameter of less than 12F (4.0 mm) for
percutaneous delivery via a catheter introducer system. In a
preferred embodiment, the filtration device will be of length "1",
preferably about 6-7 cm. As mentioned, the dual cone filter device
10 is self-anchoring on the interior of the vessel wall 28 because
of the small hook or barb 32 located on the superior ends 16 and
inferior ends 18, yet the blood filter device 10 will have
sufficient longitudinal flexibility to pass through fifty-five (55)
degrees of angulation and will not substantially distort the vessel
after deployment.
[0082] In a preferred embodiment of the filter device 10, the dual
cone filter configuration converts into an open or stent-like
configuration by actively removing the releasable retainer 22. As
depicted in FIG. 9, the releasable retainer 40 has a hook 42 with
which it can be captured by a snare or other capturing device and
pulled through a catheter for removal from the body. In this
embodiment, the releasable retainer 40 is cylindrical having
axially extending tubular apertures 44 extending its length into
which the filter legs 12 are slidably secured until removal of the
retainer 40. The releasable retainer 40 joins the filter legs 12 to
form the conical filter configuration. FIG. 10 shows a
cross-section of the releasable retainer 40 with the filter legs 12
secured within the apertures 44. FIG. 11 is an enlargement of the
cross-sectional view of the filter leg 12 within the tubular
aperture 44 of the releasable retainer 40. The diameter of the
filter leg 12 is less than the diameter of the tubular aperture 44
which enables the filter leg to be slidably released from the
releasable retainer 40 when the retainer 40 is snared. It will be
appreciated that this construction of the filter 10 offers the
possibility of providing a permanent filter, i.e., by leaving the
releasable retainer 40 in place, or converting the filter 10 to the
open configuration, and hence, substantially completely reopening
the lumen by removing the releasable member 40.
[0083] Referring again to FIG. 1, the releasable retainer 22 may
comprise a band of biodegradable material. Examples of such
materials are polylactic acid material or polyglycolic acid suture
material commonly used. The advantage of making the releasable
retainer 22 from a biodegradable material is that over time the
releasable retainer 22 will sufficiently degrade so as to permit
the filter legs 12 to move to the open configuration. Thus, the
filter device 10 passively converts from a filter configuration to
a stent-like configuration. Advantageously, this conversion occurs
without a subsequent invasive surgical procedure.
[0084] With reference now to FIG. 12, an alternate embodiment of
the invention is shown in a single cone filtration device (filter)
100. The filtration device 100 may again be inserted percutaneously
into the body using the aforementioned Seldinger technique or any
other commonly practiced and federally approved method of
insertion.
[0085] FIG. 12 shows the single cone filtration device 100 in its
expanded position and having a plurality of intraluminal filter
elements (filter legs) 102. The filter legs 102 are a flexible wire
and, in one preferred embodiment, the wires are metallic and may be
round or flattened wire. The wires may be made from a radiopaque,
non-thrombogenic, and non-ferromagnetic metal meeting the
certifications for permanently implanted medical devices according
to the ISO and will preferably be able to withstand twelve million
respiratory cycles. The wires may, in particular, consist
essentially of any of the aforementioned metals described with
respect to filter 10. In the filter 100 shown in FIG. 12, the
filter legs 102 are made of a flattened wire. Each leg 102 has a
blunted superior end 104, as discussed in the aforementioned
paragraphs describing the superior and inferior positioning within
the body, and has a small hook or barb 32 as seen in FIG. 3 and
FIG. 4.
[0086] The filter 100 has a releasable retainer 106 that joins the
superior ends 104 of the filter legs 102 forming a single, conical
filter configuration as shown in FIG. 12. In one preferred
embodiment, the retainer 106 is rounded or cap-shaped, however
alternative retainer configurations could be used. Two preferred
releasable filter embodiments are shown in FIG. 13 and FIG. 14. In
the embodiment depicted in FIG. 13, the cap-shaped releasable
retainer 106 includes a hook 108 which allows the retainer 106 to
be actively removed at any time. The hook 106 may be grasped by a
snare or other capturing device and the releasable retainer 106
removed from the body, thereby converting the single cone filter
100 to an open, tubular stent-like configuration. The embodiment
shown in FIG. 14 has a annular ring-shaped, releasable retainer
106' which may also be removed using a snare device.
[0087] As is seen in FIGS. 15 and 16, the releasable retainer 106
has a hollow interior for receiving and retaining the blunted
superior ends 104 of the filter legs 102. Upon release of the
retainer 106, the filter legs 102 are released converting the
filter 100 into an open or stent-like configuration. As seen in
FIG. 15 and FIG. 16, the interior of the cap-shaped, releasable
retainer 106 is hollow and holds the blunted superior ends 104 of
the filter legs 102 by frictional engagement.
[0088] Referring again to FIG. 12, the releasable retainer 106 may
be a band of biodegradable material such as polylactic acid
material or polyglycolic acid suture material. Similar advantages
as with filter device 10 are gained by making the releasable
retainer 22 from a biodegradable material. Namely, the filter
device 100 can be made to passively convert from a filter
configuration to a stent-like configuration. Advantageously, this
conversion occurs without a subsequent invasive surgical
procedure.
[0089] In FIG. 12, the single cone filter 100 includes axially
extending orientation members 110 to ensure centering of the filter
in the vessel and to securely engage the filter with the interior
wall of the blood vessel 28. Each orientation member 110 appears to
be an appendix on each inferior end 112 of each filter leg 102
which folds substantially toward the closed end of the cone 113 and
is substantially aligned with an axis "a" of the filter 100. In one
embodiment, each orientation member 110 may be welded or otherwise
permanently connected the blunted inferior end 112 of each filter
leg 102. In another embodiment, the orientation members 110 may be
formed from the same wire as the filter legs 102 by forming the
wire so that an acute angle is created between the filter leg
portion of the wire 102 and the orientation member portion of the
wire 110. Each axially extending orientation member 110 may have
one or more small hook or barbs 32 located along the length of the
leg 110 for engaging the interior wall of the vessel to maintain
the stability and positioning of the filter 100.
[0090] As seen in FIG. 12, the filter 100 may have a spring 114
adjacent the superior ends 104 to urge them radially outward,
thereby reverting the filter 100 to its stent-like configuration.
The spring force required to urge the filter legs 102 to the open
configuration, however, is most preferably provided by the
formation of the legs themselves in combination with the respective
orientation member 110. The releasable retainer 106 resists the
force exerted in the legs 102 by either the spring 114, or the
energy stored in the filter leg 102 itself, to retain the
filtration device 100 in the single cone filter configuration. In a
configuration of filter 100 not including a spring 114, an
additional member may be provided to join and retain the legs
together.
[0091] Referring now to FIG. 19, another embodiment of the
invention is shown in a single cone filtration device (filter) 200.
The filter 200 may be inserted percutaneously into the body using
the aforementioned Seldinger technique or by any other commonly
practiced and federally approved method of insertion.
[0092] FIG. 19 shows the filter 200 in its expanded position having
a plurality of intraluminal elements (filter legs) 202. In this
embodiment, the filter legs 202 are a flexible wire and may be
metallic and round. The wires may be made from a radiopaque,
non-thrombogenic, and non-ferromagnetic metal meeting the
certifications for permanently implanted medical devices according
to the ISO and will preferably be able to withstand twelve million
respiratory cycles. The wires may, in particular, consist
essentially of any of the aforementioned metals. Each filter leg
202 has a blunted superior end 204, and has a small hook or barb 32
as seen in FIG. 3 and FIG. 4.
[0093] The filter 200 includes a releasable retainer 206 that joins
the superior ends 204 of the filter legs 202 forming a single,
conical filter configuration as shown in FIG. 19. In one preferred
embodiment, the releasable retainer 206 is rounded or cap-shaped,
however alternative retainer configurations could be used. Two
preferred releasable retainers are releasable retainers 106 and
106' described above in connection with FIG. 13 and FIG. 14.
Equally preferred is the use of a biodegradable retainer as
discussed above. Upon release of the retainer 206, either actively
with a snaring or other capturing device or passively after
sufficient degradation of the biodegradable material, the filter
legs 202 are released converting the filter 200 into an open or
stent-like configuration.
[0094] In FIG. 19, the single cone filter 200 includes axially
extending orientation members 208 to ensure centering of the filter
in the vessel and to securely engage the filter with the interior
wall of the blood vessel 28. Each orientation member 208 appears to
be an appendix on the each inferior end 210 of each filter leg 202
which folds substantially backwards toward the tip or closed end of
the cone 211. In one embodiment, each orientation member 208 may be
welded or otherwise permanently connected to the blunted inferior
end 210 of each filter leg 202. In another embodiment, the
orientation members 208 may be formed from the same wire as the
filter legs 202 by forming the wire so that an acute angle is
created between the filter leg portion of the wire 202 and the
orientation member portion of the wire 208. Neighboring or adjacent
orientation members 208 are joined creating a wishbone-like
configuration. Such a configuration assists in maintaining filter
stability within the lumen. Each axially extending orientation
member 208 may have one or more small hook or barbs 32 located
along the length of the leg 208 for engaging the interior wall of
the vessel to maintain the stability and positioning of the filter
200. In FIG. 19, the single cone filtration device 200 may have a
spring 212 adjacent the superior ends 204 to urge them radially
outward. Alternatively, and more preferably, the configuration of
the filter legs 202 themselves in conjunction with the respective
orientation member 208 provides the energy to urge the filter legs
202 to the open configuration.
[0095] The releasable retainer 206 resists the force exerted in the
legs 202 by either the spring 212 or the filter legs themselves, to
retain the filtration device 200 in the single cone filter
configuration. FIG. 20 shows in cross-sectional view the spring 212
attached to and joining the filter legs 202 where the releasable
retainer 206 still retains the legs keeping them in a conical
configuration. FIG. 21 shows a cross-sectional view of the spring
212 urging the legs radially outwardly into an open and stent-like
configuration when the releasable retainer 206 is removed. The
small hook 32 on each blunted superior end 204 engages the wall of
the vessel for securely fixing the expanded filter within the blood
vessel.
[0096] Referring now to FIG. 22, in still another alternate
preferred embodiment, the filtration device is a single cone
filtration device 200. The filtration device 300 may be inserted
percutaneously into the body using the aforementioned Seldinger
technique or any other commonly practiced and federally approved
method of insertion not listed herein.
[0097] FIG. 22 shows the single cone filtration device 300 in its
expanded position having a plurality of filter legs 302. The legs
302 are a flexible wire and, in one preferred embodiment, the wires
are metallic and round. In another embodiment, the wires may be
flattened. The wires may be made from a radiopaque,
non-thrombogenic, and non-ferromagnetic metal meeting the
certifications for permanently implanted medical devices according
to the ISO and will preferably be able to withstand twelve million
respiratory cycles. The wires may, in particular, consist
essentially of any of the aforementioned metals. As shown in FIG.
22, each neighboring or adjacent filter leg 302 is joined at its
superior end 304. The filter 300 includes a releasable retainer 306
that joins the superior ends 304 of the filter legs 302 forming a
single, conical filter configuration as shown in FIG. 22. In one
preferred embodiment, the retainer 306 is rounded or cap-shaped,
however alternative retainer configurations could be used as
discussed above. Upon release of the retainer 306, either actively
with a snaring or other capturing device or passively after
sufficient degradation of the biodegradable retainer, the filter
legs 302 are released converting the filter 300 into an open or
stent-like configuration.
[0098] In FIG. 22, the single cone filter 300 includes axially
extending orientation members 308 to ensure centering of the filter
in the vessel and to securely engage the filter with the interior
wall of the blood vessel 28. Each orientation member 308 appears to
be an appendix on the each inferior end 310 of each filter leg 302
which folds substantially backwards toward the tip or closed end of
the cone 311 and is substantially aligned with an axis "a" of the
filter 300. In one embodiment, each orientation member 308 may be
welded or otherwise permanently connected to the blunted inferior
end 310 of each filter leg 302. In another embodiment, the
orientation members 308 may be formed from the same wire as the
filter legs 302 by forming the wire so that an acute angle is
created between the filter leg portion of the wire 302 and the
orientation member portion of the wire 308. Each axially extending
orientation member 308 may have one or more small hook or barb 32
located along the length of the leg 308 for engaging the interior
wall of the vessel to maintain the stability and positioning of the
filter 300. Preferably the force necessary to move the filter legs
302 is provide by the configuration of the filter legs 302 in
conjunction with the orientation members 308. However, in FIG. 22,
the single cone filtration device 300 may have a spring 312
adjacent the superior ends 304 to restore the filter to its
stent-like configuration by urging the filter legs 302 radially
outward. The releasable retainer 306 resists the force attempting
to return the filter legs 302 to the open configuration and retains
the filtration device 300 in the single cone filter configuration.
FIG. 23 shows the spring 312 urging the legs 302 radially outwardly
into an open and stent-like configuration after the releasable
retainer 306 has been removed. The small hook 32 of each blunted
superior end 304 engages the interior wall of the vessel 28 to
securely hold the converted filter against the wall of the vessel
28.
[0099] Referring to FIG. 24, in another alternate embodiment, the
filtration device is a single cone filtration device 400. The
filtration device 400 may be inserted percutaneously into the body
using the aforementioned Seldinger technique or any other commonly
practiced and federally approved method of insertion not listed
herein.
[0100] FIG. 24 shows the single cone filtration device 400 in its
expanded position having a plurality of filter legs 402. The legs
402 are a flexible wire and, in one preferred embodiment, the wires
are metallic and round. The wires may be made from a radiopaque,
non-thrombogenic, and non-ferromagnetic metal meeting the
certifications for permanently implanted medical devices according
to the ISO and will preferably be able to withstand twelve million
respiratory cycles. The wires may, in particular, consist
essentially of any of the aforementioned metals. The wire filter
legs 402 are corrugated to enhance filtering of blot clots. Each
leg 402 has a blunted superior end 404, as discussed in the
aforementioned paragraphs describing the superior and inferior
positioning within the body, and has a small hook or barb 32 as
seen in FIG. 3 and FIG. 4. The filter 400 includes a releasable
retainer 406 that joins the superior ends 404 of the filter legs
202 forming a single, conical filter configuration as shown in FIG.
24. In one preferred embodiment, the retainer 406 is rounded or
cap-shaped, however alternative retainer configurations could be
used as discussed above. Upon release of the retainer 406, either
actively with a snaring or other capturing device or passively
after sufficient degradation of the biodegradable retainer, the
filter legs 402 are released converting the filter 400 into an open
or stent-like configuration.
[0101] In FIG. 24, the single cone filter 400 may be configured to
include axially extending orientation members 408 to ensure
centering of the filter in the vessel and to securely engage the
filter with the interior wall of the blood vessel 28. Each
orientation member 408 appears to be an appendix on the each
inferior end 410 of each filter leg 402 which folds substantially
toward the closed end of the cone 411. In one embodiment, each
orientation member 408 may be welded or otherwise permanently
connected to the blunted inferior end 410 of each filter leg 402.
In another embodiment, the orientation members 408 may be formed
from the same wire as the filter legs 402 by forming the wire so
that an acute angle is created between the filter leg portion of
the wire 402 and the orientation member portion of the wire 408.
Each axially extending orientation member 408 may have one or more
small hook or barbs 32 located along the length of the leg 408 for
engaging the interior wall of the vessel to maintain the stability
and positioning of the filter 400. The configuration of the legs
402 and orientation members 408 may provide the force necessary to
revert the filter legs 402 to the open configuration. In FIG. 24,
the single cone filtration device 400 may have a spring 412
adjacent the superior ends 204 to revert the filter legs 402 to the
open configuration. The releasable retainer 406 resists the force
exerted in the legs 402 to retain the filtration device 400 in the
single cone filter configuration. FIG. 25 shows a cross-sectional
view of the spring 412 attached to and joining the filter legs 402
where the releasable retainer 406 still retains the legs keeping
them in a conical configuration. FIG. 26 shows a cross-sectional
view of the spring 412 urging the legs radially outwardly thereby
reverting them into an open and stent-like configuration when the
releasable retainer 406 is removed. The small hook 32 on each
blunted superior end 404 engages the wall of the vessel for
securely fixing the expanded filter within the blood vessel.
[0102] In certain preferred embodiments of a filter device
described above a spring in not needed to urge the filter legs
radially outwardly to restore the filter to its open configuration.
In FIG. 27, the single cone filter 500 is formed substantially the
same way as the single cone filter 100 shown in FIG. 12. The filter
legs, releasable retainer, and orientation members are in
accordance with the foregoing discussion associated with single
cone filter 100. In FIG. 28, the single cone filter 600 is formed
substantially the same way as single cone filter 200 shown in FIG.
19. The filter legs, releasable retainer, and orientation members
are in accordance with the discussion associated with single cone
filter 200. When the releasable retainer is removed from the single
cone filter 500 and single cone filter 600, the filters are
self-opening. Each filter leg and orientation member of filter 500
and filter 600 is formed from a single wire. The wire is bent
forming a hair-pin configuration. The energy stored in wires causes
the filter legs to self-open upon release of the retainer and
thereby create an open or stent-like configuration.
[0103] In FIG. 29, the single cone filter 700 is constructed
similarly to the aforementioned blood filters. In filter 700, each
neighboring or adjacent filter legs is connected at is superior end
and each neighboring or adjacent orientation member is connected.
Thus, filter 700 is formed from one continuous piece of wire that
has been formed into a stent-like configuration and then retained
by a releasable retainer in a filter configuration. If the wire of
filter 700 were broken at one point and the wire laid flat, the
shape of the wire may appear similar to a sinusoidal wave. In
filter 700, between each adjacent and connected filter leg, the
filter legs may have a mesh of wires to enhance filtering during
embolization. The meshed wires 703 are seen in FIG. 29.
[0104] In accordance with the preferred embodiments, the filter
legs of filters 500, 600 and 700 are retained in a releasable
retainer while in the single cone configuration. The releasable
retainer resists the force restoring the filter legs to the open
configuration and thus retains the filter legs in the single cone
filter configuration. FIG. 30 shows a cross-sectional view of the
filter legs of filters 500, 600 and 700 joined or retained by a
releasable retainer. FIG. 31 shows a cross-sectional view of the
filter legs of filters 500, 600 and 700 expanding radially
outwardly into an open and stent-like configuration when the
releasable retainer is removed. A small hook 32 on each blunted
superior end of each filter leg engages the wall of the vessel to
securely fix the expanded filter within the blood vessel. In this
expanded position, the interior of the blood vessel lumen is open
for the free-flow of blood.
[0105] As mentioned previously, the releasable retainer in each of
the aforementioned embodiments can be actively or passively
removed. FIG. 32 shows filter legs 800 that are restrained by a
releasable retainer 802 in the form of a band. The filter legs 800
form a conical filter configuration. In FIG. 32, the releasable
retainer 802 is a band the engages each of the filter legs. This
retainer 802 is generally biologically stabile, i.e., does not
degrade within the body, until being exposed to an energy stimulus
or a chemical stimulus. The waves 804 shown in FIG. 32 represent an
energy stimulus. An emitter 806 is depicted by the rod-like
structure in FIG. 32, but is not limited to such a structure
configuration. The waves 804 given off by the emitter 806 may be an
ultrasonic energy or an electrical current. In another embodiment,
the emitter 806 may release waves 804 of a chemical stimulus that
breaks or dissolves the retaining band 800. Preferably the band
remains structurally stable until it is exposed to the either the
mechanical, electrical or chemical stimulus. For example, a polymer
material responsive to ultrasound energy to initiate a degradation
process is described in U.S. Pat. No. 4,657,543, the disclosure of
which is incorporated by reference. In an alternative embodiment,
the retainer 802 is a stainless steel material that may be
electrolytically disintegrated as is known in the art. After
exposure to the energy stimulus, the retainer 802 begins to degrade
similar to the above-described biodegradable releasable retainers
or otherwise sufficiently structurally weakens so as to permit the
release of the filter legs 800. Upon release, as shown in FIG. 33,
the filter legs 800 expand to form the an open or stent-like
configuration when the retainer 802 degrades as a result of
exposure to either an energy stimulus or a chemical stimulus.
[0106] In FIG. 34, the basket-type filter 810 is constructed
similarly to the aforementioned single cone filters except that the
releasable retainer joins both ends of the filter 810. In this
embodiment, the releasable retainer may be a first releasable
retainer 812 and a second releasable retainer 814. The filter 810
may be inserted percutaneously into the body using the
aforementioned Seldinger technique or any other commonly practiced
and approved method of insertion. The intraluminal filter elements
(filter legs) 811 are a flexible wire and, in one preferred
embodiment, may be round or flattened wire. The wires may be made
from a radiopaque, non-thrombogenic, and non-ferromagnetic metal
meeting the certifications for permanently implanted medical
devices according to the ISO and will preferably be able to
withstand twelve million respiratory cycles. The wires may, in
particular, consist essentially of any of the aforementioned metals
described with respect to filter 10. The filter legs 811 are
gathered at one end by releasable retainer 812 and at the other end
by releasable retainer 814. A filter web 816 extends between the
filter legs 811. The filter web 816 may be made of woven metal or
may be a plurality individual members extending between the filter
legs 811. Because of the symmetric configuration of the basket-type
filter 810, the filter 810 does not have designated superior and
inferior ends as described previously in connection with the single
and dual cone filter configurations. For this reason, the filter
810 may be implanted in the vena cava from above or below. Each
retainer 812, 814 of filter 810 includes a hook 813, 815 which
allows the respective retainer 812, 814 to be actively removed at
any time like the retainer depicted in FIG. 13. The hooks 813, 815
may be grasped by a snare or other capturing device and the
retainer 812, 814 removed from the body. As is shown in FIG. 35,
the basket-type filter 810 converts to a single cone filter
configuration when the inferiorly positioned one of the retainers
812, 814 is removed. When the remaining superiorly positioned one
of the retainers 812, 814 is removed, the single cone configuration
converts to an open, stent-like configuration as is depicted in
FIG. 36. The superior retainer is the one of the retainers
positioned upstream relative to blood flow, and the inferior
retainer is the other of the retainers positioned downstream
relative to blood flow. In alterative embodiments of the invention,
the basket-type filter 810 may include biodegradable retainers
which, advantageously, allow the conversion to occur without a
subsequent invasive surgical procedure. In additional embodiments
of the invention, the basket-type filter 810 may include retainers
that are releasable upon exposure to a form of mechanical,
electrical or chemical stimulus.
[0107] In accordance with additional preferred embodiments of the
invention, a filter is placed in an artery downstream from the
diseased portion of the arterial vessel to prevent large pieces
dislodged plaque as well as any other potentially harmful embolic
material from occluding smaller vessels. A filter inserted
downstream catches plaque dislodged by during the treatment
procedure, such as endarterectomy, and retains it until the plaque
is removed from the filter by a vacuuming procedure. In addition to
catching dislodged plaque, the filters catches harmful blood clots
in the bloodstream. Such blood clots may develop as a result of
damage to the normal healthy lining of the blood vessel caused by
the plaque removal. For example, when blood platelets come into
contact with the site of vessel damage, they become activated,
adhering to the site and initiate the formation of a blood clot or
thrombus. The thrombus may enlarge until it blocks the vessel at
the site, or the continued flow of blood past the thrombus may
cause it to dislodge. Thromboembolism may have serious consequences
for patients suffering from atherosclerosis if the free floating
clot, or embolus, completely plugs a smaller vessel as it migrates
downstream. Thus, it is desirable to place filters in the
bloodstream to catch any potentially harmful pieces of plaque or
other embolic material.
[0108] Similarly, with balloon angioplasty, plaque may dislodge
from the arterial wall and enter the blood stream. As mentioned
previously, it would be desirable to catch the plaque in a filter
and remove it from the body before a cerebral vascular accident
occurs.
[0109] With reference to FIG. 37, a filter 820, in accordance with
an alternate preferred embodiment of the invention, is shown. The
filter 820 has a dual cone configuration and includes a plurality
of intraluminal filter elements (filter legs) 822. The filter 820
may be inserted percutaneously into the body using the
aforementioned Seldinger technique or any other commonly practiced
and approved method of insertion. The filter legs 822 are a
flexible wire and, in one preferred embodiment, may be round or
flattened wire. The wires may be made from a radiopaque,
non-thrombogenic, and non-ferromagnetic metal meeting the
certifications for permanently implanted medical devices according
to the ISO and will preferably be able to withstand twelve million
respiratory cycles. The wires may, in particular, consist
essentially of any of the aforementioned metals described with
respect to filter 10. The filter legs 822 each have a blunted
superior end 824 and inferior end 826. Superior and inferior are
used in their ordinary sense to refer to the filter's position
within the body. The superior ends 824 are positioned upstream
relative to blood flow, and the inferior ends 826 are positioned
downstream relative to blood flow. The direction of blood flow is
indicated in FIG. 37 and FIG. 38 by the arrow 828.
[0110] In FIG. 37, the filter legs 822 are joined by a releasable
retainer 830 at a location between the superior ends 824 and the
inferior ends 826. The releasable retainer 830 secures the filter
legs 822 in the dual cone configuration. The filter 820 may have a
first member 832 adjacent the superior ends 824 and a second member
834 adjacent the inferior ends 826. The first member 832 and the
second member 834 support the filter legs 822 radially and
axially.
[0111] The filter 820 has a filter web 836 extending between the
portion of the filter legs 822 that is disposed between the
releasable retainer 830 and the inferior ends 826. The filter web
836 is shown only extending between two of the plurality of filter
legs 822, but it should be understood that in a preferred
embodiment of the invention the filter web 836 may extend between
all of the filter legs 822, or some portion of the filter legs 822.
The filter web 836 may be made of woven metal or may be a plurality
of individual members extending between the filter legs 822. The
filter web 836 enhances the effectiveness of the filter 820 to
retain pieces of dislodged plaque and thrombotic material.
[0112] The releasable retainer 830 retains the filter legs 822 in
the intraluminal dual cone filter configuration, e.g., resists the
tendency of the filter legs 822 to return to an open configuration.
That is, the first member 832 and the second member 834 maintain
the relative spacing of the filter legs 822, and in general, retain
the filter legs 822 in a cylindrical or stent-like configuration
(similar to that of the filter 10 shown in FIG. 6). The releasable
retainer 830, by engaging the filter legs 822, restricts the
central portion of the filter legs 822 and retains the filter legs
822 in the dual cone filter configuration. By withdrawing the
releasable retainer 830 from the filter legs 822, the filter legs
822 are permitted to completely open into the cylindrical
configuration. The first member 832 and the second member 834 are
each shown as an expanding annular spring; however, one of ordinary
skill in the art will appreciate that alternative configurations
may be used.
[0113] Each of the filter legs 822 of the filter 820 may be
constructed similar to the single filter leg 12 of the filter 10 as
depicted in FIG. 2. Each blunted superior end 824 and inferior end
826 is flattened and may include a small hook or barb (such as barb
32, best seen in FIG. 3 and FIG. 4) that engages the interior wall
of the blood vessel 838. These barbs help secure the filter 820
within the lumen of an arterial blood vessel 838 and resist the
pressures of the blood pumping through the arterial system. It is
not necessary that each end, 824 and 826, of each filter leg 822
include a barb. Instead, the barbs may be disposed on alternating
ends, or may be disposed on preselected ones of the ends. Such an
arrangement of the filter 820, with barbs disposed on alternating
ends of the filter legs 822, may enhance deployment of the filter
into the vessel. In a filter having barbs disposed on the end of
each filter leg, it is possible that, as the filter is discharged
from the introducer catheter, the barbs of adjoining filter legs
may engage the vessel wall before they have expanded to their full
radial extension. The result is the filter may not fully deploy. By
providing barbs on alternating filter leg ends, or even fewer ends,
the tendency for the barbs to improperly engage the vessel is
reduced.
[0114] Each filter leg 822 may also include a partially corrugated
portion along its length (similar to the corrugated portion 34 of
the filter 10 illustrated in FIG. 2). Within a relatively short
period of time after implantation, the barbs on the superior ends
824 and inferior ends 826 of the filter legs 822, which are in
contact with the interior wall of the vessel 838, become
permanently connected with the interior wall of the blood vessel
838. The corrugated portion permits outward expansion of the filter
leg 822 after release of the releasable retainer 830 without
displacement of the superior end 824 or the inferior end 826 as the
filter is converted to the stent-like configuration. This
arrangement of the filter leg 822 reduces the likelihood of
damaging the interior wall of the blood vessel 838 upon opening of
the filter 820 from the filter configuration to the open,
stent-like configuration.
[0115] In a preferred embodiment, the filtration device 820 must be
openable to a diameter of not less than "d", about 2-10 mm, and
preferably about 4 mm, yet collapsible to a diameter of less than
8F (2.6 mm) for percutaneous delivery via a catheter introducer
system. In a preferred embodiment, the filtration device will be of
length "1", preferably about 2-10 mm. As mentioned, the dual cone
filter device 820 is self-anchoring on the interior of the vessel
wall 838 because of the barbs located on the superior ends 824 and
inferior ends 826, yet the blood filter device 820 will have
sufficient longitudinal flexibility to pass through fifty-five (55)
degrees of angulation and will not substantially distort the vessel
after deployment.
[0116] In a preferred embodiment of the filter device 820, the dual
cone filter configuration converts into an open or stent-like
configuration by actively removing the releasable retainer 830.
This conversion to a stent-like configuration is especially
desirable when treating atherosclerotic disease as described above.
For example, after a balloon angioplasty procedure, stents are
often inserted into the treated region of an artery to keep the
lumen open, maintain blood flow and provide a scaffolding for
tissue growth.
[0117] The releasable retainer 830 may be constructed similar to
the retainer 40 depicted in FIG. 9 and include a hook 842 with
which it can be captured by a snare or other capturing device and
pulled through a catheter for removal from the body. Like the
retainer in FIG. 9, the releasable retainer 830 may be cylindrical
having axially extending tubular apertures extending its length
into which the filter legs 822 are slidably secured until removal
of the retainer 830. As shown in FIG. 37, the releasable retainer
830 is a band, for example of suture material, that may be cut and
removed via a catheter. Alternatively, the releasable retainer 830
may be a band of biodegradable material. Examples of such materials
are polylactic acid material or polyglycolic acid suture material
commonly used. The advantage of making the releasable retainer 830
from a biodegradable material is that over time the releasable
retainer 830 will sufficiently degrade so as to permit the filter
legs 822 to move to the open configuration. Thus, the filter device
820 passively converts from a filter configuration to a stent-like
configuration, advantageously occuring without a subsequent
invasive surgical procedure.
[0118] Referring now to FIG. 38, in accordance with yet another
embodiment of the invention, a single cone filtration device
(filter) 900 is shown. The filter 900 may be inserted
percutaneously into the body using the aforementioned Seldinger
technique or by any other commonly practiced and approved method of
insertion.
[0119] FIG. 38 shows the filter 900 in its expanded position having
a plurality of intraluminal elements (filter legs) 902. In this
embodiment, the filter legs 902 are constructed from flexible wire
that may be metallic and round. The wires are preferably
radiopaque, non-thrombogenic, and non-ferromagnetic metal meeting
the certifications for permanently implanted medical devices
according to the ISO and will preferably be able to withstand
twelve million respiratory cycles. In particular, the wire may
consist essentially of any of the aforementioned metals.
[0120] Each filter leg 902 has a blunted inferior end 904, and each
inferior end 904 may be formed to include a barb. Other embodiments
of filter 900 may include alternating ends formed with a barb, or
each end of selected ones of the filter legs 902 including a barb.
The single cone filter illustrated in FIG. 38 may be formed
substantially the same way as single cone filter 200. As such, the
filter legs 902, and orientation members 906 are formed in
accordance with the discussion associated with single cone filter
200.
[0121] The filter 900 shown in FIG. 38 has a releasable retainer
908 that joins the superior ends of the filter legs 902 forming a
single, conical configuration as shown. In one preferred
embodiment, the retainer 908 is rounded or cap-shaped, however
alternate retainer configurations could be used. In the embodiment
depicted in FIG. 39, the cap-shaped releasable retainer 908
includes a hook 909 which allows the retainer 908 to be actively
removed at any time. The hook 909 may be grasped by a snare or
other capturing device and the releasable retainer 908 removed from
the body, thereby converting the single cone filter 900 to an open,
tubular, stent-like configuration. As shown in FIG. 39A, the
releasable retainer 908 may be formed to include axially extending
tubular apertures 903 into which the filter legs 902 are slidably
engaged similar to those shown in connection with retainer 40 of
FIG. 9.
[0122] When the releasable retainer 908 is removed from the single
cone filter 900, the filter is self-opening to an open, stent-like
configuration. Each filter leg 902 and orientation member 906 may
be formed from a single wire that is formed into a hairpin-like
configuration as shown in FIG. 38. Alternatively, all the filter
legs 902 and orientation members 906 may be formed from a
continuous piece of wire and retained by the releasable retainer
908 in a filter configuration. Upon release of the retainer 908
from the filter, the elastic energy stored in the wire(s) causes
the filter legs to self-open and thereby create an open or
stent-like configuration.
[0123] In accordance with the preferred embodiments of the
invention, the filter legs 902 are connected by a filter web 910
that consists of a wire mesh. This filter web enhances the
effectiveness of the filter 900 for retaining small pieces of
plaque during the treatment of vascular disease. As is best
illustrated in FIG. 40, when single cone filter 900 is in the
filter configuration the filter web 910 fills the lumen of the
blood vessel, contacting the interior wall of the arterial blood
vessel 838, to catch migrating pieces of dislodged plaque and
thrombotic material in the bloodstream.
[0124] In accordance with a method of treating atherosclerotic
disease by endarterectomy, balloon angioplasty, atherectomy or
other interventional methods, a filter, e.g., a filter 820 or a
filter 900, may be inserted into the vessel being treated and
downstream, relative to the direction of blood flow (indicated by
arrow 828 in FIGS. 41-44), from the area of the vessel being
treated. As shown in FIG. 41, a filter 900 may be placed downstream
from deposits of atherosclerotic plaque 912 that have accumulated
on the interior lining of an arterial blood vessel 838. As shown in
FIG. 42, the filter 900 catches harmful debris 914 in the
bloodstream including plaque dislodged by the treatment procedure
as well as thrombotic material. The filter 900 retains this debris
914 until the debris 914 is removed from the filter 900 by a
vacuuming procedure known by one skilled in the art. Some residual
atherosclerotic plaque 916 may remain on the interior lining of the
arterial blood vessel 838. In FIG. 43, at the completion of the
treatment, the residual plaque 916 is removed from the interior
lining (traces of plaque may still line the arterial wall yet are
not depicted in FIGS. 43 and 44) of the arterial blood vessel 838
and all debris 914 is removed from the filter 900. Finally, as
depicted in FIG. 44, the filter 900 may convert to its open,
stent-like configuration if of the releasable retainer is removed,
either passively or actively as described above in connection with
the vena cava filters. The filter 900 in the open, stent-like
configuration restores vessel patency, keeps the lumen open and
provides a scaffolding for the growth of new tissue on the interior
lining of the arterial blood vessel 838. While it is not
anticipated that the filter will be left for extended periods in
the filter configuration, and instead it is likely the filter will
be converted to the open, stent-like configuration shortly after
completing the treatment, such methods of treatment utilizing a
filter as shown herein are within the scope of the invention.
[0125] In an alternate embodiment, any of the aforementioned
filters may be made both passively self-opening and entirely
biodegradable based upon the materials selected to form the filter
structure. The filter itself, and particularly the intraluminal
elements (filter legs), the orientation members and the filter web,
where necessary, may be formed of a biodegradable material which
degrades within the body after a specified period of time. Such
materials are biocompatible with the body which means that they are
physiologically tolerable. Preferably, such biocompatible materials
do not cause undesirable physiological conditions that may result
in changes in the structure and function of living tissues in the
body. In one preferred embodiment, the filter may be composed
essentially of the biodegradable and biocompatible material
polylactic acid (pla). An alternate preferred material is the
copolymer of L-lactide and ..epsilon..-caprolactone as described in
U.S. Pat. No. 5,670,161, the disclosure of which is hereby
incorporated by reference. The releasable retainer used in
conjunction with the filters composed substantially of
biodegradable materials is made of a second biodegradable and
biocompatible material. In one preferred embodiment, the releasable
retainer is made of the biodegradable material polyglycolic acid
(pga). The biodegradable material selected for the filter structure
has a degradation rate (d1) preferably slower than a degradation
rate (d2) of the biodegradable material selected for the releasable
retainer(s). Thus, the releasable retainer(s) will degrade or
dissolve first thereby releasing the filter legs and converting the
filter into a stent-like configuration. The filter legs then move
into contact with the lumen walls and in relatively short period of
time are incorporated by endothelial tissue. After a further period
of time, i.e., the difference between the filter degradation rate
(d1) and the retainer degradation rate (d2), the filter will begin
to degrade within the body. A preferred first degradation rate (d1)
may be up to one year while a preferred second degradation rate
(d2) may be approximately 21 weeks. Advantageously, because of the
biodegradable composition of the filter and the retainer, none of
the filter materials will remain in the body. Thus, a filter
constructed in accordance with this embodiment of the invention may
be particularly preferred by surgeon wherein the risk of embolism
is transient. It will be further appreciated that the foregoing
described biodegradable materials, equivalent materials, and
improvements to such materials, suitable for use in forming a
filter structure are contemplated to be within the scope of the
invention.
[0126] The invention has been described in terms of several
preferred embodiments. The description of these embodiments should
in no way be considered limiting of the broad scope of the
invention set forth in the following claims.
* * * * *